Input: add support for Azoteq IQS7222A/B/C
authorJeff LaBundy <jeff@labundy.com>
Sat, 9 Apr 2022 02:15:20 +0000 (19:15 -0700)
committerDmitry Torokhov <dmitry.torokhov@gmail.com>
Sat, 9 Apr 2022 02:28:12 +0000 (19:28 -0700)
This patch adds support for the Azoteq IQS7222A/B/C family of
capacitive touch controllers.

Signed-off-by: Jeff LaBundy <jeff@labundy.com>
Link: https://lore.kernel.org/r/20220403221659.865997-3-jeff@labundy.com
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
drivers/input/misc/Kconfig
drivers/input/misc/Makefile
drivers/input/misc/iqs7222.c [new file with mode: 0644]

index dd5227c..a18ab73 100644 (file)
@@ -762,6 +762,16 @@ config INPUT_IQS626A
          To compile this driver as a module, choose M here: the
          module will be called iqs626a.
 
+config INPUT_IQS7222
+       tristate "Azoteq IQS7222A/B/C capacitive touch controller"
+       depends on I2C
+       help
+         Say Y to enable support for the Azoteq IQS7222A/B/C family
+         of capacitive touch controllers.
+
+         To compile this driver as a module, choose M here: the
+         module will be called iqs7222.
+
 config INPUT_CMA3000
        tristate "VTI CMA3000 Tri-axis accelerometer"
        help
index b92c53a..28dfc44 100644 (file)
@@ -44,6 +44,7 @@ obj-$(CONFIG_HP_SDC_RTC)              += hp_sdc_rtc.o
 obj-$(CONFIG_INPUT_IMS_PCU)            += ims-pcu.o
 obj-$(CONFIG_INPUT_IQS269A)            += iqs269a.o
 obj-$(CONFIG_INPUT_IQS626A)            += iqs626a.o
+obj-$(CONFIG_INPUT_IQS7222)            += iqs7222.o
 obj-$(CONFIG_INPUT_KEYSPAN_REMOTE)     += keyspan_remote.o
 obj-$(CONFIG_INPUT_KXTJ9)              += kxtj9.o
 obj-$(CONFIG_INPUT_M68K_BEEP)          += m68kspkr.o
diff --git a/drivers/input/misc/iqs7222.c b/drivers/input/misc/iqs7222.c
new file mode 100644 (file)
index 0000000..d800f71
--- /dev/null
@@ -0,0 +1,2445 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Azoteq IQS7222A/B/C Capacitive Touch Controller
+ *
+ * Copyright (C) 2022 Jeff LaBundy <jeff@labundy.com>
+ */
+
+#include <linux/bits.h>
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/gpio/consumer.h>
+#include <linux/i2c.h>
+#include <linux/input.h>
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/ktime.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/property.h>
+#include <linux/slab.h>
+#include <asm/unaligned.h>
+
+#define IQS7222_PROD_NUM                       0x00
+#define IQS7222_PROD_NUM_A                     840
+#define IQS7222_PROD_NUM_B                     698
+#define IQS7222_PROD_NUM_C                     863
+
+#define IQS7222_SYS_STATUS                     0x10
+#define IQS7222_SYS_STATUS_RESET               BIT(3)
+#define IQS7222_SYS_STATUS_ATI_ERROR           BIT(1)
+#define IQS7222_SYS_STATUS_ATI_ACTIVE          BIT(0)
+
+#define IQS7222_CHAN_SETUP_0_REF_MODE_MASK     GENMASK(15, 14)
+#define IQS7222_CHAN_SETUP_0_REF_MODE_FOLLOW   BIT(15)
+#define IQS7222_CHAN_SETUP_0_REF_MODE_REF      BIT(14)
+#define IQS7222_CHAN_SETUP_0_CHAN_EN           BIT(8)
+
+#define IQS7222_SLDR_SETUP_0_CHAN_CNT_MASK     GENMASK(2, 0)
+#define IQS7222_SLDR_SETUP_2_RES_MASK          GENMASK(15, 8)
+#define IQS7222_SLDR_SETUP_2_RES_SHIFT         8
+#define IQS7222_SLDR_SETUP_2_TOP_SPEED_MASK    GENMASK(7, 0)
+#define IQS7222_SLDR_SETUP_3_CHAN_SEL_MASK     GENMASK(9, 0)
+
+#define IQS7222_GPIO_SETUP_0_GPIO_EN           BIT(0)
+
+#define IQS7222_SYS_SETUP                      0xD0
+#define IQS7222_SYS_SETUP_INTF_MODE_MASK       GENMASK(7, 6)
+#define IQS7222_SYS_SETUP_INTF_MODE_TOUCH      BIT(7)
+#define IQS7222_SYS_SETUP_INTF_MODE_EVENT      BIT(6)
+#define IQS7222_SYS_SETUP_PWR_MODE_MASK                GENMASK(5, 4)
+#define IQS7222_SYS_SETUP_PWR_MODE_AUTO                IQS7222_SYS_SETUP_PWR_MODE_MASK
+#define IQS7222_SYS_SETUP_REDO_ATI             BIT(2)
+#define IQS7222_SYS_SETUP_ACK_RESET            BIT(0)
+
+#define IQS7222_EVENT_MASK_ATI                 BIT(12)
+
+#define IQS7222_COMMS_HOLD                     BIT(0)
+#define IQS7222_COMMS_ERROR                    0xEEEE
+#define IQS7222_COMMS_RETRY_MS                 50
+#define IQS7222_COMMS_TIMEOUT_MS               100
+#define IQS7222_RESET_TIMEOUT_MS               250
+#define IQS7222_ATI_TIMEOUT_MS                 2000
+
+#define IQS7222_MAX_COLS_STAT                  8
+#define IQS7222_MAX_COLS_CYCLE                 3
+#define IQS7222_MAX_COLS_GLBL                  3
+#define IQS7222_MAX_COLS_BTN                   3
+#define IQS7222_MAX_COLS_CHAN                  6
+#define IQS7222_MAX_COLS_FILT                  2
+#define IQS7222_MAX_COLS_SLDR                  11
+#define IQS7222_MAX_COLS_GPIO                  3
+#define IQS7222_MAX_COLS_SYS                   13
+
+#define IQS7222_MAX_CHAN                       20
+#define IQS7222_MAX_SLDR                       2
+
+#define IQS7222_NUM_RETRIES                    5
+#define IQS7222_REG_OFFSET                     0x100
+
+enum iqs7222_reg_key_id {
+       IQS7222_REG_KEY_NONE,
+       IQS7222_REG_KEY_PROX,
+       IQS7222_REG_KEY_TOUCH,
+       IQS7222_REG_KEY_DEBOUNCE,
+       IQS7222_REG_KEY_TAP,
+       IQS7222_REG_KEY_AXIAL,
+       IQS7222_REG_KEY_WHEEL,
+       IQS7222_REG_KEY_NO_WHEEL,
+       IQS7222_REG_KEY_RESERVED
+};
+
+enum iqs7222_reg_grp_id {
+       IQS7222_REG_GRP_STAT,
+       IQS7222_REG_GRP_CYCLE,
+       IQS7222_REG_GRP_GLBL,
+       IQS7222_REG_GRP_BTN,
+       IQS7222_REG_GRP_CHAN,
+       IQS7222_REG_GRP_FILT,
+       IQS7222_REG_GRP_SLDR,
+       IQS7222_REG_GRP_GPIO,
+       IQS7222_REG_GRP_SYS,
+       IQS7222_NUM_REG_GRPS
+};
+
+static const char * const iqs7222_reg_grp_names[] = {
+       [IQS7222_REG_GRP_CYCLE] = "cycle",
+       [IQS7222_REG_GRP_CHAN] = "channel",
+       [IQS7222_REG_GRP_SLDR] = "slider",
+       [IQS7222_REG_GRP_GPIO] = "gpio",
+};
+
+static const unsigned int iqs7222_max_cols[] = {
+       [IQS7222_REG_GRP_STAT] = IQS7222_MAX_COLS_STAT,
+       [IQS7222_REG_GRP_CYCLE] = IQS7222_MAX_COLS_CYCLE,
+       [IQS7222_REG_GRP_GLBL] = IQS7222_MAX_COLS_GLBL,
+       [IQS7222_REG_GRP_BTN] = IQS7222_MAX_COLS_BTN,
+       [IQS7222_REG_GRP_CHAN] = IQS7222_MAX_COLS_CHAN,
+       [IQS7222_REG_GRP_FILT] = IQS7222_MAX_COLS_FILT,
+       [IQS7222_REG_GRP_SLDR] = IQS7222_MAX_COLS_SLDR,
+       [IQS7222_REG_GRP_GPIO] = IQS7222_MAX_COLS_GPIO,
+       [IQS7222_REG_GRP_SYS] = IQS7222_MAX_COLS_SYS,
+};
+
+static const unsigned int iqs7222_gpio_links[] = { 2, 5, 6, };
+
+struct iqs7222_event_desc {
+       const char *name;
+       u16 mask;
+       u16 val;
+       u16 enable;
+       enum iqs7222_reg_key_id reg_key;
+};
+
+static const struct iqs7222_event_desc iqs7222_kp_events[] = {
+       {
+               .name = "event-prox",
+               .enable = BIT(0),
+               .reg_key = IQS7222_REG_KEY_PROX,
+       },
+       {
+               .name = "event-touch",
+               .enable = BIT(1),
+               .reg_key = IQS7222_REG_KEY_TOUCH,
+       },
+};
+
+static const struct iqs7222_event_desc iqs7222_sl_events[] = {
+       { .name = "event-press", },
+       {
+               .name = "event-tap",
+               .mask = BIT(0),
+               .val = BIT(0),
+               .enable = BIT(0),
+               .reg_key = IQS7222_REG_KEY_TAP,
+       },
+       {
+               .name = "event-swipe-pos",
+               .mask = BIT(5) | BIT(1),
+               .val = BIT(1),
+               .enable = BIT(1),
+               .reg_key = IQS7222_REG_KEY_AXIAL,
+       },
+       {
+               .name = "event-swipe-neg",
+               .mask = BIT(5) | BIT(1),
+               .val = BIT(5) | BIT(1),
+               .enable = BIT(1),
+               .reg_key = IQS7222_REG_KEY_AXIAL,
+       },
+       {
+               .name = "event-flick-pos",
+               .mask = BIT(5) | BIT(2),
+               .val = BIT(2),
+               .enable = BIT(2),
+               .reg_key = IQS7222_REG_KEY_AXIAL,
+       },
+       {
+               .name = "event-flick-neg",
+               .mask = BIT(5) | BIT(2),
+               .val = BIT(5) | BIT(2),
+               .enable = BIT(2),
+               .reg_key = IQS7222_REG_KEY_AXIAL,
+       },
+};
+
+struct iqs7222_reg_grp_desc {
+       u16 base;
+       int num_row;
+       int num_col;
+};
+
+struct iqs7222_dev_desc {
+       u16 prod_num;
+       u16 fw_major;
+       u16 fw_minor;
+       u16 sldr_res;
+       u16 touch_link;
+       u16 wheel_enable;
+       int allow_offset;
+       int event_offset;
+       int comms_offset;
+       struct iqs7222_reg_grp_desc reg_grps[IQS7222_NUM_REG_GRPS];
+};
+
+static const struct iqs7222_dev_desc iqs7222_devs[] = {
+       {
+               .prod_num = IQS7222_PROD_NUM_A,
+               .fw_major = 1,
+               .fw_minor = 12,
+               .sldr_res = U8_MAX * 16,
+               .touch_link = 1768,
+               .allow_offset = 9,
+               .event_offset = 10,
+               .comms_offset = 12,
+               .reg_grps = {
+                       [IQS7222_REG_GRP_STAT] = {
+                               .base = IQS7222_SYS_STATUS,
+                               .num_row = 1,
+                               .num_col = 8,
+                       },
+                       [IQS7222_REG_GRP_CYCLE] = {
+                               .base = 0x8000,
+                               .num_row = 7,
+                               .num_col = 3,
+                       },
+                       [IQS7222_REG_GRP_GLBL] = {
+                               .base = 0x8700,
+                               .num_row = 1,
+                               .num_col = 3,
+                       },
+                       [IQS7222_REG_GRP_BTN] = {
+                               .base = 0x9000,
+                               .num_row = 12,
+                               .num_col = 3,
+                       },
+                       [IQS7222_REG_GRP_CHAN] = {
+                               .base = 0xA000,
+                               .num_row = 12,
+                               .num_col = 6,
+                       },
+                       [IQS7222_REG_GRP_FILT] = {
+                               .base = 0xAC00,
+                               .num_row = 1,
+                               .num_col = 2,
+                       },
+                       [IQS7222_REG_GRP_SLDR] = {
+                               .base = 0xB000,
+                               .num_row = 2,
+                               .num_col = 11,
+                       },
+                       [IQS7222_REG_GRP_GPIO] = {
+                               .base = 0xC000,
+                               .num_row = 1,
+                               .num_col = 3,
+                       },
+                       [IQS7222_REG_GRP_SYS] = {
+                               .base = IQS7222_SYS_SETUP,
+                               .num_row = 1,
+                               .num_col = 13,
+                       },
+               },
+       },
+       {
+               .prod_num = IQS7222_PROD_NUM_B,
+               .fw_major = 1,
+               .fw_minor = 43,
+               .event_offset = 10,
+               .comms_offset = 11,
+               .reg_grps = {
+                       [IQS7222_REG_GRP_STAT] = {
+                               .base = IQS7222_SYS_STATUS,
+                               .num_row = 1,
+                               .num_col = 6,
+                       },
+                       [IQS7222_REG_GRP_CYCLE] = {
+                               .base = 0x8000,
+                               .num_row = 10,
+                               .num_col = 2,
+                       },
+                       [IQS7222_REG_GRP_GLBL] = {
+                               .base = 0x8A00,
+                               .num_row = 1,
+                               .num_col = 3,
+                       },
+                       [IQS7222_REG_GRP_BTN] = {
+                               .base = 0x9000,
+                               .num_row = 20,
+                               .num_col = 2,
+                       },
+                       [IQS7222_REG_GRP_CHAN] = {
+                               .base = 0xB000,
+                               .num_row = 20,
+                               .num_col = 4,
+                       },
+                       [IQS7222_REG_GRP_FILT] = {
+                               .base = 0xC400,
+                               .num_row = 1,
+                               .num_col = 2,
+                       },
+                       [IQS7222_REG_GRP_SYS] = {
+                               .base = IQS7222_SYS_SETUP,
+                               .num_row = 1,
+                               .num_col = 13,
+                       },
+               },
+       },
+       {
+               .prod_num = IQS7222_PROD_NUM_B,
+               .fw_major = 1,
+               .fw_minor = 27,
+               .reg_grps = {
+                       [IQS7222_REG_GRP_STAT] = {
+                               .base = IQS7222_SYS_STATUS,
+                               .num_row = 1,
+                               .num_col = 6,
+                       },
+                       [IQS7222_REG_GRP_CYCLE] = {
+                               .base = 0x8000,
+                               .num_row = 10,
+                               .num_col = 2,
+                       },
+                       [IQS7222_REG_GRP_GLBL] = {
+                               .base = 0x8A00,
+                               .num_row = 1,
+                               .num_col = 3,
+                       },
+                       [IQS7222_REG_GRP_BTN] = {
+                               .base = 0x9000,
+                               .num_row = 20,
+                               .num_col = 2,
+                       },
+                       [IQS7222_REG_GRP_CHAN] = {
+                               .base = 0xB000,
+                               .num_row = 20,
+                               .num_col = 4,
+                       },
+                       [IQS7222_REG_GRP_FILT] = {
+                               .base = 0xC400,
+                               .num_row = 1,
+                               .num_col = 2,
+                       },
+                       [IQS7222_REG_GRP_SYS] = {
+                               .base = IQS7222_SYS_SETUP,
+                               .num_row = 1,
+                               .num_col = 10,
+                       },
+               },
+       },
+       {
+               .prod_num = IQS7222_PROD_NUM_C,
+               .fw_major = 2,
+               .fw_minor = 6,
+               .sldr_res = U16_MAX,
+               .touch_link = 1686,
+               .wheel_enable = BIT(3),
+               .event_offset = 9,
+               .comms_offset = 10,
+               .reg_grps = {
+                       [IQS7222_REG_GRP_STAT] = {
+                               .base = IQS7222_SYS_STATUS,
+                               .num_row = 1,
+                               .num_col = 6,
+                       },
+                       [IQS7222_REG_GRP_CYCLE] = {
+                               .base = 0x8000,
+                               .num_row = 5,
+                               .num_col = 3,
+                       },
+                       [IQS7222_REG_GRP_GLBL] = {
+                               .base = 0x8500,
+                               .num_row = 1,
+                               .num_col = 3,
+                       },
+                       [IQS7222_REG_GRP_BTN] = {
+                               .base = 0x9000,
+                               .num_row = 10,
+                               .num_col = 3,
+                       },
+                       [IQS7222_REG_GRP_CHAN] = {
+                               .base = 0xA000,
+                               .num_row = 10,
+                               .num_col = 6,
+                       },
+                       [IQS7222_REG_GRP_FILT] = {
+                               .base = 0xAA00,
+                               .num_row = 1,
+                               .num_col = 2,
+                       },
+                       [IQS7222_REG_GRP_SLDR] = {
+                               .base = 0xB000,
+                               .num_row = 2,
+                               .num_col = 10,
+                       },
+                       [IQS7222_REG_GRP_GPIO] = {
+                               .base = 0xC000,
+                               .num_row = 3,
+                               .num_col = 3,
+                       },
+                       [IQS7222_REG_GRP_SYS] = {
+                               .base = IQS7222_SYS_SETUP,
+                               .num_row = 1,
+                               .num_col = 12,
+                       },
+               },
+       },
+       {
+               .prod_num = IQS7222_PROD_NUM_C,
+               .fw_major = 1,
+               .fw_minor = 13,
+               .sldr_res = U16_MAX,
+               .touch_link = 1674,
+               .wheel_enable = BIT(3),
+               .event_offset = 9,
+               .comms_offset = 10,
+               .reg_grps = {
+                       [IQS7222_REG_GRP_STAT] = {
+                               .base = IQS7222_SYS_STATUS,
+                               .num_row = 1,
+                               .num_col = 6,
+                       },
+                       [IQS7222_REG_GRP_CYCLE] = {
+                               .base = 0x8000,
+                               .num_row = 5,
+                               .num_col = 3,
+                       },
+                       [IQS7222_REG_GRP_GLBL] = {
+                               .base = 0x8500,
+                               .num_row = 1,
+                               .num_col = 3,
+                       },
+                       [IQS7222_REG_GRP_BTN] = {
+                               .base = 0x9000,
+                               .num_row = 10,
+                               .num_col = 3,
+                       },
+                       [IQS7222_REG_GRP_CHAN] = {
+                               .base = 0xA000,
+                               .num_row = 10,
+                               .num_col = 6,
+                       },
+                       [IQS7222_REG_GRP_FILT] = {
+                               .base = 0xAA00,
+                               .num_row = 1,
+                               .num_col = 2,
+                       },
+                       [IQS7222_REG_GRP_SLDR] = {
+                               .base = 0xB000,
+                               .num_row = 2,
+                               .num_col = 10,
+                       },
+                       [IQS7222_REG_GRP_GPIO] = {
+                               .base = 0xC000,
+                               .num_row = 1,
+                               .num_col = 3,
+                       },
+                       [IQS7222_REG_GRP_SYS] = {
+                               .base = IQS7222_SYS_SETUP,
+                               .num_row = 1,
+                               .num_col = 11,
+                       },
+               },
+       },
+};
+
+struct iqs7222_prop_desc {
+       const char *name;
+       enum iqs7222_reg_grp_id reg_grp;
+       enum iqs7222_reg_key_id reg_key;
+       int reg_offset;
+       int reg_shift;
+       int reg_width;
+       int val_pitch;
+       int val_min;
+       int val_max;
+       bool invert;
+       const char *label;
+};
+
+static const struct iqs7222_prop_desc iqs7222_props[] = {
+       {
+               .name = "azoteq,conv-period",
+               .reg_grp = IQS7222_REG_GRP_CYCLE,
+               .reg_offset = 0,
+               .reg_shift = 8,
+               .reg_width = 8,
+               .label = "conversion period",
+       },
+       {
+               .name = "azoteq,conv-frac",
+               .reg_grp = IQS7222_REG_GRP_CYCLE,
+               .reg_offset = 0,
+               .reg_shift = 0,
+               .reg_width = 8,
+               .label = "conversion frequency fractional divider",
+       },
+       {
+               .name = "azoteq,rx-float-inactive",
+               .reg_grp = IQS7222_REG_GRP_CYCLE,
+               .reg_offset = 1,
+               .reg_shift = 6,
+               .reg_width = 1,
+               .invert = true,
+       },
+       {
+               .name = "azoteq,dead-time-enable",
+               .reg_grp = IQS7222_REG_GRP_CYCLE,
+               .reg_offset = 1,
+               .reg_shift = 5,
+               .reg_width = 1,
+       },
+       {
+               .name = "azoteq,tx-freq-fosc",
+               .reg_grp = IQS7222_REG_GRP_CYCLE,
+               .reg_offset = 1,
+               .reg_shift = 4,
+               .reg_width = 1,
+       },
+       {
+               .name = "azoteq,vbias-enable",
+               .reg_grp = IQS7222_REG_GRP_CYCLE,
+               .reg_offset = 1,
+               .reg_shift = 3,
+               .reg_width = 1,
+       },
+       {
+               .name = "azoteq,sense-mode",
+               .reg_grp = IQS7222_REG_GRP_CYCLE,
+               .reg_offset = 1,
+               .reg_shift = 0,
+               .reg_width = 3,
+               .val_max = 3,
+               .label = "sensing mode",
+       },
+       {
+               .name = "azoteq,iref-enable",
+               .reg_grp = IQS7222_REG_GRP_CYCLE,
+               .reg_offset = 2,
+               .reg_shift = 10,
+               .reg_width = 1,
+       },
+       {
+               .name = "azoteq,iref-level",
+               .reg_grp = IQS7222_REG_GRP_CYCLE,
+               .reg_offset = 2,
+               .reg_shift = 4,
+               .reg_width = 4,
+               .label = "current reference level",
+       },
+       {
+               .name = "azoteq,iref-trim",
+               .reg_grp = IQS7222_REG_GRP_CYCLE,
+               .reg_offset = 2,
+               .reg_shift = 0,
+               .reg_width = 4,
+               .label = "current reference trim",
+       },
+       {
+               .name = "azoteq,rf-filt-enable",
+               .reg_grp = IQS7222_REG_GRP_GLBL,
+               .reg_offset = 0,
+               .reg_shift = 15,
+               .reg_width = 1,
+       },
+       {
+               .name = "azoteq,max-counts",
+               .reg_grp = IQS7222_REG_GRP_GLBL,
+               .reg_offset = 0,
+               .reg_shift = 13,
+               .reg_width = 2,
+               .label = "maximum counts",
+       },
+       {
+               .name = "azoteq,auto-mode",
+               .reg_grp = IQS7222_REG_GRP_GLBL,
+               .reg_offset = 0,
+               .reg_shift = 2,
+               .reg_width = 2,
+               .label = "number of conversions",
+       },
+       {
+               .name = "azoteq,ati-frac-div-fine",
+               .reg_grp = IQS7222_REG_GRP_GLBL,
+               .reg_offset = 1,
+               .reg_shift = 9,
+               .reg_width = 5,
+               .label = "ATI fine fractional divider",
+       },
+       {
+               .name = "azoteq,ati-frac-div-coarse",
+               .reg_grp = IQS7222_REG_GRP_GLBL,
+               .reg_offset = 1,
+               .reg_shift = 0,
+               .reg_width = 5,
+               .label = "ATI coarse fractional divider",
+       },
+       {
+               .name = "azoteq,ati-comp-select",
+               .reg_grp = IQS7222_REG_GRP_GLBL,
+               .reg_offset = 2,
+               .reg_shift = 0,
+               .reg_width = 10,
+               .label = "ATI compensation selection",
+       },
+       {
+               .name = "azoteq,ati-band",
+               .reg_grp = IQS7222_REG_GRP_CHAN,
+               .reg_offset = 0,
+               .reg_shift = 12,
+               .reg_width = 2,
+               .label = "ATI band",
+       },
+       {
+               .name = "azoteq,global-halt",
+               .reg_grp = IQS7222_REG_GRP_CHAN,
+               .reg_offset = 0,
+               .reg_shift = 11,
+               .reg_width = 1,
+       },
+       {
+               .name = "azoteq,invert-enable",
+               .reg_grp = IQS7222_REG_GRP_CHAN,
+               .reg_offset = 0,
+               .reg_shift = 10,
+               .reg_width = 1,
+       },
+       {
+               .name = "azoteq,dual-direction",
+               .reg_grp = IQS7222_REG_GRP_CHAN,
+               .reg_offset = 0,
+               .reg_shift = 9,
+               .reg_width = 1,
+       },
+       {
+               .name = "azoteq,samp-cap-double",
+               .reg_grp = IQS7222_REG_GRP_CHAN,
+               .reg_offset = 0,
+               .reg_shift = 3,
+               .reg_width = 1,
+       },
+       {
+               .name = "azoteq,vref-half",
+               .reg_grp = IQS7222_REG_GRP_CHAN,
+               .reg_offset = 0,
+               .reg_shift = 2,
+               .reg_width = 1,
+       },
+       {
+               .name = "azoteq,proj-bias",
+               .reg_grp = IQS7222_REG_GRP_CHAN,
+               .reg_offset = 0,
+               .reg_shift = 0,
+               .reg_width = 2,
+               .label = "projected bias current",
+       },
+       {
+               .name = "azoteq,ati-target",
+               .reg_grp = IQS7222_REG_GRP_CHAN,
+               .reg_offset = 1,
+               .reg_shift = 8,
+               .reg_width = 8,
+               .val_pitch = 8,
+               .label = "ATI target",
+       },
+       {
+               .name = "azoteq,ati-base",
+               .reg_grp = IQS7222_REG_GRP_CHAN,
+               .reg_offset = 1,
+               .reg_shift = 3,
+               .reg_width = 5,
+               .val_pitch = 16,
+               .label = "ATI base",
+       },
+       {
+               .name = "azoteq,ati-mode",
+               .reg_grp = IQS7222_REG_GRP_CHAN,
+               .reg_offset = 1,
+               .reg_shift = 0,
+               .reg_width = 3,
+               .val_max = 5,
+               .label = "ATI mode",
+       },
+       {
+               .name = "azoteq,ati-frac-div-fine",
+               .reg_grp = IQS7222_REG_GRP_CHAN,
+               .reg_offset = 2,
+               .reg_shift = 9,
+               .reg_width = 5,
+               .label = "ATI fine fractional divider",
+       },
+       {
+               .name = "azoteq,ati-frac-mult-coarse",
+               .reg_grp = IQS7222_REG_GRP_CHAN,
+               .reg_offset = 2,
+               .reg_shift = 5,
+               .reg_width = 4,
+               .label = "ATI coarse fractional multiplier",
+       },
+       {
+               .name = "azoteq,ati-frac-div-coarse",
+               .reg_grp = IQS7222_REG_GRP_CHAN,
+               .reg_offset = 2,
+               .reg_shift = 0,
+               .reg_width = 5,
+               .label = "ATI coarse fractional divider",
+       },
+       {
+               .name = "azoteq,ati-comp-div",
+               .reg_grp = IQS7222_REG_GRP_CHAN,
+               .reg_offset = 3,
+               .reg_shift = 11,
+               .reg_width = 5,
+               .label = "ATI compensation divider",
+       },
+       {
+               .name = "azoteq,ati-comp-select",
+               .reg_grp = IQS7222_REG_GRP_CHAN,
+               .reg_offset = 3,
+               .reg_shift = 0,
+               .reg_width = 10,
+               .label = "ATI compensation selection",
+       },
+       {
+               .name = "azoteq,debounce-exit",
+               .reg_grp = IQS7222_REG_GRP_BTN,
+               .reg_key = IQS7222_REG_KEY_DEBOUNCE,
+               .reg_offset = 0,
+               .reg_shift = 12,
+               .reg_width = 4,
+               .label = "debounce exit factor",
+       },
+       {
+               .name = "azoteq,debounce-enter",
+               .reg_grp = IQS7222_REG_GRP_BTN,
+               .reg_key = IQS7222_REG_KEY_DEBOUNCE,
+               .reg_offset = 0,
+               .reg_shift = 8,
+               .reg_width = 4,
+               .label = "debounce entrance factor",
+       },
+       {
+               .name = "azoteq,thresh",
+               .reg_grp = IQS7222_REG_GRP_BTN,
+               .reg_key = IQS7222_REG_KEY_PROX,
+               .reg_offset = 0,
+               .reg_shift = 0,
+               .reg_width = 8,
+               .val_max = 127,
+               .label = "threshold",
+       },
+       {
+               .name = "azoteq,thresh",
+               .reg_grp = IQS7222_REG_GRP_BTN,
+               .reg_key = IQS7222_REG_KEY_TOUCH,
+               .reg_offset = 1,
+               .reg_shift = 0,
+               .reg_width = 8,
+               .label = "threshold",
+       },
+       {
+               .name = "azoteq,hyst",
+               .reg_grp = IQS7222_REG_GRP_BTN,
+               .reg_key = IQS7222_REG_KEY_TOUCH,
+               .reg_offset = 1,
+               .reg_shift = 8,
+               .reg_width = 8,
+               .label = "hysteresis",
+       },
+       {
+               .name = "azoteq,lta-beta-lp",
+               .reg_grp = IQS7222_REG_GRP_FILT,
+               .reg_offset = 0,
+               .reg_shift = 12,
+               .reg_width = 4,
+               .label = "low-power mode long-term average beta",
+       },
+       {
+               .name = "azoteq,lta-beta-np",
+               .reg_grp = IQS7222_REG_GRP_FILT,
+               .reg_offset = 0,
+               .reg_shift = 8,
+               .reg_width = 4,
+               .label = "normal-power mode long-term average beta",
+       },
+       {
+               .name = "azoteq,counts-beta-lp",
+               .reg_grp = IQS7222_REG_GRP_FILT,
+               .reg_offset = 0,
+               .reg_shift = 4,
+               .reg_width = 4,
+               .label = "low-power mode counts beta",
+       },
+       {
+               .name = "azoteq,counts-beta-np",
+               .reg_grp = IQS7222_REG_GRP_FILT,
+               .reg_offset = 0,
+               .reg_shift = 0,
+               .reg_width = 4,
+               .label = "normal-power mode counts beta",
+       },
+       {
+               .name = "azoteq,lta-fast-beta-lp",
+               .reg_grp = IQS7222_REG_GRP_FILT,
+               .reg_offset = 1,
+               .reg_shift = 4,
+               .reg_width = 4,
+               .label = "low-power mode long-term average fast beta",
+       },
+       {
+               .name = "azoteq,lta-fast-beta-np",
+               .reg_grp = IQS7222_REG_GRP_FILT,
+               .reg_offset = 1,
+               .reg_shift = 0,
+               .reg_width = 4,
+               .label = "normal-power mode long-term average fast beta",
+       },
+       {
+               .name = "azoteq,lower-cal",
+               .reg_grp = IQS7222_REG_GRP_SLDR,
+               .reg_offset = 0,
+               .reg_shift = 8,
+               .reg_width = 8,
+               .label = "lower calibration",
+       },
+       {
+               .name = "azoteq,static-beta",
+               .reg_grp = IQS7222_REG_GRP_SLDR,
+               .reg_key = IQS7222_REG_KEY_NO_WHEEL,
+               .reg_offset = 0,
+               .reg_shift = 6,
+               .reg_width = 1,
+       },
+       {
+               .name = "azoteq,bottom-beta",
+               .reg_grp = IQS7222_REG_GRP_SLDR,
+               .reg_key = IQS7222_REG_KEY_NO_WHEEL,
+               .reg_offset = 0,
+               .reg_shift = 3,
+               .reg_width = 3,
+               .label = "bottom beta",
+       },
+       {
+               .name = "azoteq,static-beta",
+               .reg_grp = IQS7222_REG_GRP_SLDR,
+               .reg_key = IQS7222_REG_KEY_WHEEL,
+               .reg_offset = 0,
+               .reg_shift = 7,
+               .reg_width = 1,
+       },
+       {
+               .name = "azoteq,bottom-beta",
+               .reg_grp = IQS7222_REG_GRP_SLDR,
+               .reg_key = IQS7222_REG_KEY_WHEEL,
+               .reg_offset = 0,
+               .reg_shift = 4,
+               .reg_width = 3,
+               .label = "bottom beta",
+       },
+       {
+               .name = "azoteq,bottom-speed",
+               .reg_grp = IQS7222_REG_GRP_SLDR,
+               .reg_offset = 1,
+               .reg_shift = 8,
+               .reg_width = 8,
+               .label = "bottom speed",
+       },
+       {
+               .name = "azoteq,upper-cal",
+               .reg_grp = IQS7222_REG_GRP_SLDR,
+               .reg_offset = 1,
+               .reg_shift = 0,
+               .reg_width = 8,
+               .label = "upper calibration",
+       },
+       {
+               .name = "azoteq,gesture-max-ms",
+               .reg_grp = IQS7222_REG_GRP_SLDR,
+               .reg_key = IQS7222_REG_KEY_TAP,
+               .reg_offset = 9,
+               .reg_shift = 8,
+               .reg_width = 8,
+               .val_pitch = 4,
+               .label = "maximum gesture time",
+       },
+       {
+               .name = "azoteq,gesture-min-ms",
+               .reg_grp = IQS7222_REG_GRP_SLDR,
+               .reg_key = IQS7222_REG_KEY_TAP,
+               .reg_offset = 9,
+               .reg_shift = 3,
+               .reg_width = 5,
+               .val_pitch = 4,
+               .label = "minimum gesture time",
+       },
+       {
+               .name = "azoteq,gesture-dist",
+               .reg_grp = IQS7222_REG_GRP_SLDR,
+               .reg_key = IQS7222_REG_KEY_AXIAL,
+               .reg_offset = 10,
+               .reg_shift = 8,
+               .reg_width = 8,
+               .val_pitch = 16,
+               .label = "gesture distance",
+       },
+       {
+               .name = "azoteq,gesture-max-ms",
+               .reg_grp = IQS7222_REG_GRP_SLDR,
+               .reg_key = IQS7222_REG_KEY_AXIAL,
+               .reg_offset = 10,
+               .reg_shift = 0,
+               .reg_width = 8,
+               .val_pitch = 4,
+               .label = "maximum gesture time",
+       },
+       {
+               .name = "drive-open-drain",
+               .reg_grp = IQS7222_REG_GRP_GPIO,
+               .reg_offset = 0,
+               .reg_shift = 1,
+               .reg_width = 1,
+       },
+       {
+               .name = "azoteq,timeout-ati-ms",
+               .reg_grp = IQS7222_REG_GRP_SYS,
+               .reg_offset = 1,
+               .reg_shift = 0,
+               .reg_width = 16,
+               .val_pitch = 500,
+               .label = "ATI error timeout",
+       },
+       {
+               .name = "azoteq,rate-ati-ms",
+               .reg_grp = IQS7222_REG_GRP_SYS,
+               .reg_offset = 2,
+               .reg_shift = 0,
+               .reg_width = 16,
+               .label = "ATI report rate",
+       },
+       {
+               .name = "azoteq,timeout-np-ms",
+               .reg_grp = IQS7222_REG_GRP_SYS,
+               .reg_offset = 3,
+               .reg_shift = 0,
+               .reg_width = 16,
+               .label = "normal-power mode timeout",
+       },
+       {
+               .name = "azoteq,rate-np-ms",
+               .reg_grp = IQS7222_REG_GRP_SYS,
+               .reg_offset = 4,
+               .reg_shift = 0,
+               .reg_width = 16,
+               .val_max = 3000,
+               .label = "normal-power mode report rate",
+       },
+       {
+               .name = "azoteq,timeout-lp-ms",
+               .reg_grp = IQS7222_REG_GRP_SYS,
+               .reg_offset = 5,
+               .reg_shift = 0,
+               .reg_width = 16,
+               .label = "low-power mode timeout",
+       },
+       {
+               .name = "azoteq,rate-lp-ms",
+               .reg_grp = IQS7222_REG_GRP_SYS,
+               .reg_offset = 6,
+               .reg_shift = 0,
+               .reg_width = 16,
+               .val_max = 3000,
+               .label = "low-power mode report rate",
+       },
+       {
+               .name = "azoteq,timeout-ulp-ms",
+               .reg_grp = IQS7222_REG_GRP_SYS,
+               .reg_offset = 7,
+               .reg_shift = 0,
+               .reg_width = 16,
+               .label = "ultra-low-power mode timeout",
+       },
+       {
+               .name = "azoteq,rate-ulp-ms",
+               .reg_grp = IQS7222_REG_GRP_SYS,
+               .reg_offset = 8,
+               .reg_shift = 0,
+               .reg_width = 16,
+               .val_max = 3000,
+               .label = "ultra-low-power mode report rate",
+       },
+};
+
+struct iqs7222_private {
+       const struct iqs7222_dev_desc *dev_desc;
+       struct gpio_desc *reset_gpio;
+       struct gpio_desc *irq_gpio;
+       struct i2c_client *client;
+       struct input_dev *keypad;
+       unsigned int kp_type[IQS7222_MAX_CHAN][ARRAY_SIZE(iqs7222_kp_events)];
+       unsigned int kp_code[IQS7222_MAX_CHAN][ARRAY_SIZE(iqs7222_kp_events)];
+       unsigned int sl_code[IQS7222_MAX_SLDR][ARRAY_SIZE(iqs7222_sl_events)];
+       unsigned int sl_axis[IQS7222_MAX_SLDR];
+       u16 cycle_setup[IQS7222_MAX_CHAN / 2][IQS7222_MAX_COLS_CYCLE];
+       u16 glbl_setup[IQS7222_MAX_COLS_GLBL];
+       u16 btn_setup[IQS7222_MAX_CHAN][IQS7222_MAX_COLS_BTN];
+       u16 chan_setup[IQS7222_MAX_CHAN][IQS7222_MAX_COLS_CHAN];
+       u16 filt_setup[IQS7222_MAX_COLS_FILT];
+       u16 sldr_setup[IQS7222_MAX_SLDR][IQS7222_MAX_COLS_SLDR];
+       u16 gpio_setup[ARRAY_SIZE(iqs7222_gpio_links)][IQS7222_MAX_COLS_GPIO];
+       u16 sys_setup[IQS7222_MAX_COLS_SYS];
+};
+
+static u16 *iqs7222_setup(struct iqs7222_private *iqs7222,
+                         enum iqs7222_reg_grp_id reg_grp, int row)
+{
+       switch (reg_grp) {
+       case IQS7222_REG_GRP_CYCLE:
+               return iqs7222->cycle_setup[row];
+
+       case IQS7222_REG_GRP_GLBL:
+               return iqs7222->glbl_setup;
+
+       case IQS7222_REG_GRP_BTN:
+               return iqs7222->btn_setup[row];
+
+       case IQS7222_REG_GRP_CHAN:
+               return iqs7222->chan_setup[row];
+
+       case IQS7222_REG_GRP_FILT:
+               return iqs7222->filt_setup;
+
+       case IQS7222_REG_GRP_SLDR:
+               return iqs7222->sldr_setup[row];
+
+       case IQS7222_REG_GRP_GPIO:
+               return iqs7222->gpio_setup[row];
+
+       case IQS7222_REG_GRP_SYS:
+               return iqs7222->sys_setup;
+
+       default:
+               return NULL;
+       }
+}
+
+static int iqs7222_irq_poll(struct iqs7222_private *iqs7222, u16 timeout_ms)
+{
+       ktime_t irq_timeout = ktime_add_ms(ktime_get(), timeout_ms);
+       int ret;
+
+       do {
+               usleep_range(1000, 1100);
+
+               ret = gpiod_get_value_cansleep(iqs7222->irq_gpio);
+               if (ret < 0)
+                       return ret;
+               else if (ret > 0)
+                       return 0;
+       } while (ktime_compare(ktime_get(), irq_timeout) < 0);
+
+       return -EBUSY;
+}
+
+static int iqs7222_hard_reset(struct iqs7222_private *iqs7222)
+{
+       struct i2c_client *client = iqs7222->client;
+       int error;
+
+       if (!iqs7222->reset_gpio)
+               return 0;
+
+       gpiod_set_value_cansleep(iqs7222->reset_gpio, 1);
+       usleep_range(1000, 1100);
+
+       gpiod_set_value_cansleep(iqs7222->reset_gpio, 0);
+
+       error = iqs7222_irq_poll(iqs7222, IQS7222_RESET_TIMEOUT_MS);
+       if (error)
+               dev_err(&client->dev, "Failed to reset device: %d\n", error);
+
+       return error;
+}
+
+static int iqs7222_force_comms(struct iqs7222_private *iqs7222)
+{
+       u8 msg_buf[] = { 0xFF, 0x00, };
+       int ret;
+
+       /*
+        * The device cannot communicate until it asserts its interrupt (RDY)
+        * pin. Attempts to do so while RDY is deasserted return an ACK; how-
+        * ever all write data is ignored, and all read data returns 0xEE.
+        *
+        * Unsolicited communication must be preceded by a special force com-
+        * munication command, after which the device eventually asserts its
+        * RDY pin and agrees to communicate.
+        *
+        * Regardless of whether communication is forced or the result of an
+        * interrupt, the device automatically deasserts its RDY pin once it
+        * detects an I2C stop condition, or a timeout expires.
+        */
+       ret = gpiod_get_value_cansleep(iqs7222->irq_gpio);
+       if (ret < 0)
+               return ret;
+       else if (ret > 0)
+               return 0;
+
+       ret = i2c_master_send(iqs7222->client, msg_buf, sizeof(msg_buf));
+       if (ret < (int)sizeof(msg_buf)) {
+               if (ret >= 0)
+                       ret = -EIO;
+
+               /*
+                * The datasheet states that the host must wait to retry any
+                * failed attempt to communicate over I2C.
+                */
+               msleep(IQS7222_COMMS_RETRY_MS);
+               return ret;
+       }
+
+       return iqs7222_irq_poll(iqs7222, IQS7222_COMMS_TIMEOUT_MS);
+}
+
+static int iqs7222_read_burst(struct iqs7222_private *iqs7222,
+                             u16 reg, void *val, u16 num_val)
+{
+       u8 reg_buf[sizeof(__be16)];
+       int ret, i;
+       struct i2c_client *client = iqs7222->client;
+       struct i2c_msg msg[] = {
+               {
+                       .addr = client->addr,
+                       .flags = 0,
+                       .len = reg > U8_MAX ? sizeof(reg) : sizeof(u8),
+                       .buf = reg_buf,
+               },
+               {
+                       .addr = client->addr,
+                       .flags = I2C_M_RD,
+                       .len = num_val * sizeof(__le16),
+                       .buf = (u8 *)val,
+               },
+       };
+
+       if (reg > U8_MAX)
+               put_unaligned_be16(reg, reg_buf);
+       else
+               *reg_buf = (u8)reg;
+
+       /*
+        * The following loop protects against an edge case in which the RDY
+        * pin is automatically deasserted just as the read is initiated. In
+        * that case, the read must be retried using forced communication.
+        */
+       for (i = 0; i < IQS7222_NUM_RETRIES; i++) {
+               ret = iqs7222_force_comms(iqs7222);
+               if (ret < 0)
+                       continue;
+
+               ret = i2c_transfer(client->adapter, msg, ARRAY_SIZE(msg));
+               if (ret < (int)ARRAY_SIZE(msg)) {
+                       if (ret >= 0)
+                               ret = -EIO;
+
+                       msleep(IQS7222_COMMS_RETRY_MS);
+                       continue;
+               }
+
+               if (get_unaligned_le16(msg[1].buf) == IQS7222_COMMS_ERROR) {
+                       ret = -ENODATA;
+                       continue;
+               }
+
+               ret = 0;
+               break;
+       }
+
+       /*
+        * The following delay ensures the device has deasserted the RDY pin
+        * following the I2C stop condition.
+        */
+       usleep_range(50, 100);
+
+       if (ret < 0)
+               dev_err(&client->dev,
+                       "Failed to read from address 0x%04X: %d\n", reg, ret);
+
+       return ret;
+}
+
+static int iqs7222_read_word(struct iqs7222_private *iqs7222, u16 reg, u16 *val)
+{
+       __le16 val_buf;
+       int error;
+
+       error = iqs7222_read_burst(iqs7222, reg, &val_buf, 1);
+       if (error)
+               return error;
+
+       *val = le16_to_cpu(val_buf);
+
+       return 0;
+}
+
+static int iqs7222_write_burst(struct iqs7222_private *iqs7222,
+                              u16 reg, const void *val, u16 num_val)
+{
+       int reg_len = reg > U8_MAX ? sizeof(reg) : sizeof(u8);
+       int val_len = num_val * sizeof(__le16);
+       int msg_len = reg_len + val_len;
+       int ret, i;
+       struct i2c_client *client = iqs7222->client;
+       u8 *msg_buf;
+
+       msg_buf = kzalloc(msg_len, GFP_KERNEL);
+       if (!msg_buf)
+               return -ENOMEM;
+
+       if (reg > U8_MAX)
+               put_unaligned_be16(reg, msg_buf);
+       else
+               *msg_buf = (u8)reg;
+
+       memcpy(msg_buf + reg_len, val, val_len);
+
+       /*
+        * The following loop protects against an edge case in which the RDY
+        * pin is automatically asserted just before the force communication
+        * command is sent.
+        *
+        * In that case, the subsequent I2C stop condition tricks the device
+        * into preemptively deasserting the RDY pin and the command must be
+        * sent again.
+        */
+       for (i = 0; i < IQS7222_NUM_RETRIES; i++) {
+               ret = iqs7222_force_comms(iqs7222);
+               if (ret < 0)
+                       continue;
+
+               ret = i2c_master_send(client, msg_buf, msg_len);
+               if (ret < msg_len) {
+                       if (ret >= 0)
+                               ret = -EIO;
+
+                       msleep(IQS7222_COMMS_RETRY_MS);
+                       continue;
+               }
+
+               ret = 0;
+               break;
+       }
+
+       kfree(msg_buf);
+
+       usleep_range(50, 100);
+
+       if (ret < 0)
+               dev_err(&client->dev,
+                       "Failed to write to address 0x%04X: %d\n", reg, ret);
+
+       return ret;
+}
+
+static int iqs7222_write_word(struct iqs7222_private *iqs7222, u16 reg, u16 val)
+{
+       __le16 val_buf = cpu_to_le16(val);
+
+       return iqs7222_write_burst(iqs7222, reg, &val_buf, 1);
+}
+
+static int iqs7222_ati_trigger(struct iqs7222_private *iqs7222)
+{
+       struct i2c_client *client = iqs7222->client;
+       ktime_t ati_timeout;
+       u16 sys_status = 0;
+       u16 sys_setup = iqs7222->sys_setup[0] & ~IQS7222_SYS_SETUP_ACK_RESET;
+       int error, i;
+
+       for (i = 0; i < IQS7222_NUM_RETRIES; i++) {
+               /*
+                * Trigger ATI from streaming and normal-power modes so that
+                * the RDY pin continues to be asserted during ATI.
+                */
+               error = iqs7222_write_word(iqs7222, IQS7222_SYS_SETUP,
+                                          sys_setup |
+                                          IQS7222_SYS_SETUP_REDO_ATI);
+               if (error)
+                       return error;
+
+               ati_timeout = ktime_add_ms(ktime_get(), IQS7222_ATI_TIMEOUT_MS);
+
+               do {
+                       error = iqs7222_irq_poll(iqs7222,
+                                                IQS7222_COMMS_TIMEOUT_MS);
+                       if (error)
+                               continue;
+
+                       error = iqs7222_read_word(iqs7222, IQS7222_SYS_STATUS,
+                                                 &sys_status);
+                       if (error)
+                               return error;
+
+                       if (sys_status & IQS7222_SYS_STATUS_ATI_ACTIVE)
+                               continue;
+
+                       if (sys_status & IQS7222_SYS_STATUS_ATI_ERROR)
+                               break;
+
+                       /*
+                        * Use stream-in-touch mode if either slider reports
+                        * absolute position.
+                        */
+                       sys_setup |= test_bit(EV_ABS, iqs7222->keypad->evbit)
+                                  ? IQS7222_SYS_SETUP_INTF_MODE_TOUCH
+                                  : IQS7222_SYS_SETUP_INTF_MODE_EVENT;
+                       sys_setup |= IQS7222_SYS_SETUP_PWR_MODE_AUTO;
+
+                       return iqs7222_write_word(iqs7222, IQS7222_SYS_SETUP,
+                                                 sys_setup);
+               } while (ktime_compare(ktime_get(), ati_timeout) < 0);
+
+               dev_err(&client->dev,
+                       "ATI attempt %d of %d failed with status 0x%02X, %s\n",
+                       i + 1, IQS7222_NUM_RETRIES, (u8)sys_status,
+                       i < IQS7222_NUM_RETRIES ? "retrying..." : "stopping");
+       }
+
+       return -ETIMEDOUT;
+}
+
+static int iqs7222_dev_init(struct iqs7222_private *iqs7222, int dir)
+{
+       const struct iqs7222_dev_desc *dev_desc = iqs7222->dev_desc;
+       int comms_offset = dev_desc->comms_offset;
+       int error, i, j, k;
+
+       /*
+        * Take advantage of the stop-bit disable function, if available, to
+        * save the trouble of having to reopen a communication window after
+        * each burst read or write.
+        */
+       if (comms_offset) {
+               u16 comms_setup;
+
+               error = iqs7222_read_word(iqs7222,
+                                         IQS7222_SYS_SETUP + comms_offset,
+                                         &comms_setup);
+               if (error)
+                       return error;
+
+               error = iqs7222_write_word(iqs7222,
+                                          IQS7222_SYS_SETUP + comms_offset,
+                                          comms_setup | IQS7222_COMMS_HOLD);
+               if (error)
+                       return error;
+       }
+
+       for (i = 0; i < IQS7222_NUM_REG_GRPS; i++) {
+               int num_row = dev_desc->reg_grps[i].num_row;
+               int num_col = dev_desc->reg_grps[i].num_col;
+               u16 reg = dev_desc->reg_grps[i].base;
+               __le16 *val_buf;
+               u16 *val;
+
+               if (!num_col)
+                       continue;
+
+               val = iqs7222_setup(iqs7222, i, 0);
+               if (!val)
+                       continue;
+
+               val_buf = kcalloc(num_col, sizeof(__le16), GFP_KERNEL);
+               if (!val_buf)
+                       return -ENOMEM;
+
+               for (j = 0; j < num_row; j++) {
+                       switch (dir) {
+                       case READ:
+                               error = iqs7222_read_burst(iqs7222, reg,
+                                                          val_buf, num_col);
+                               for (k = 0; k < num_col; k++)
+                                       val[k] = le16_to_cpu(val_buf[k]);
+                               break;
+
+                       case WRITE:
+                               for (k = 0; k < num_col; k++)
+                                       val_buf[k] = cpu_to_le16(val[k]);
+                               error = iqs7222_write_burst(iqs7222, reg,
+                                                           val_buf, num_col);
+                               break;
+
+                       default:
+                               error = -EINVAL;
+                       }
+
+                       if (error)
+                               break;
+
+                       reg += IQS7222_REG_OFFSET;
+                       val += iqs7222_max_cols[i];
+               }
+
+               kfree(val_buf);
+
+               if (error)
+                       return error;
+       }
+
+       if (comms_offset) {
+               u16 comms_setup;
+
+               error = iqs7222_read_word(iqs7222,
+                                         IQS7222_SYS_SETUP + comms_offset,
+                                         &comms_setup);
+               if (error)
+                       return error;
+
+               error = iqs7222_write_word(iqs7222,
+                                          IQS7222_SYS_SETUP + comms_offset,
+                                          comms_setup & ~IQS7222_COMMS_HOLD);
+               if (error)
+                       return error;
+       }
+
+       if (dir == READ)
+               return 0;
+
+       return iqs7222_ati_trigger(iqs7222);
+}
+
+static int iqs7222_dev_info(struct iqs7222_private *iqs7222)
+{
+       struct i2c_client *client = iqs7222->client;
+       bool prod_num_valid = false;
+       __le16 dev_id[3];
+       int error, i;
+
+       error = iqs7222_read_burst(iqs7222, IQS7222_PROD_NUM, dev_id,
+                                  ARRAY_SIZE(dev_id));
+       if (error)
+               return error;
+
+       for (i = 0; i < ARRAY_SIZE(iqs7222_devs); i++) {
+               if (le16_to_cpu(dev_id[0]) != iqs7222_devs[i].prod_num)
+                       continue;
+
+               prod_num_valid = true;
+
+               if (le16_to_cpu(dev_id[1]) < iqs7222_devs[i].fw_major)
+                       continue;
+
+               if (le16_to_cpu(dev_id[2]) < iqs7222_devs[i].fw_minor)
+                       continue;
+
+               iqs7222->dev_desc = &iqs7222_devs[i];
+               return 0;
+       }
+
+       if (prod_num_valid)
+               dev_err(&client->dev, "Unsupported firmware revision: %u.%u\n",
+                       le16_to_cpu(dev_id[1]), le16_to_cpu(dev_id[2]));
+       else
+               dev_err(&client->dev, "Unrecognized product number: %u\n",
+                       le16_to_cpu(dev_id[0]));
+
+       return -EINVAL;
+}
+
+static int iqs7222_gpio_select(struct iqs7222_private *iqs7222,
+                              struct fwnode_handle *child_node,
+                              int child_enable, u16 child_link)
+{
+       const struct iqs7222_dev_desc *dev_desc = iqs7222->dev_desc;
+       struct i2c_client *client = iqs7222->client;
+       int num_gpio = dev_desc->reg_grps[IQS7222_REG_GRP_GPIO].num_row;
+       int error, count, i;
+       unsigned int gpio_sel[ARRAY_SIZE(iqs7222_gpio_links)];
+
+       if (!num_gpio)
+               return 0;
+
+       if (!fwnode_property_present(child_node, "azoteq,gpio-select"))
+               return 0;
+
+       count = fwnode_property_count_u32(child_node, "azoteq,gpio-select");
+       if (count > num_gpio) {
+               dev_err(&client->dev, "Invalid number of %s GPIOs\n",
+                       fwnode_get_name(child_node));
+               return -EINVAL;
+       } else if (count < 0) {
+               dev_err(&client->dev, "Failed to count %s GPIOs: %d\n",
+                       fwnode_get_name(child_node), count);
+               return count;
+       }
+
+       error = fwnode_property_read_u32_array(child_node,
+                                              "azoteq,gpio-select",
+                                              gpio_sel, count);
+       if (error) {
+               dev_err(&client->dev, "Failed to read %s GPIOs: %d\n",
+                       fwnode_get_name(child_node), error);
+               return error;
+       }
+
+       for (i = 0; i < count; i++) {
+               u16 *gpio_setup;
+
+               if (gpio_sel[i] >= num_gpio) {
+                       dev_err(&client->dev, "Invalid %s GPIO: %u\n",
+                               fwnode_get_name(child_node), gpio_sel[i]);
+                       return -EINVAL;
+               }
+
+               gpio_setup = iqs7222->gpio_setup[gpio_sel[i]];
+
+               if (gpio_setup[2] && child_link != gpio_setup[2]) {
+                       dev_err(&client->dev,
+                               "Conflicting GPIO %u event types\n",
+                               gpio_sel[i]);
+                       return -EINVAL;
+               }
+
+               gpio_setup[0] |= IQS7222_GPIO_SETUP_0_GPIO_EN;
+               gpio_setup[1] |= child_enable;
+               gpio_setup[2] = child_link;
+       }
+
+       return 0;
+}
+
+static int iqs7222_parse_props(struct iqs7222_private *iqs7222,
+                              struct fwnode_handle **child_node,
+                              int child_index,
+                              enum iqs7222_reg_grp_id reg_grp,
+                              enum iqs7222_reg_key_id reg_key)
+{
+       u16 *setup = iqs7222_setup(iqs7222, reg_grp, child_index);
+       struct fwnode_handle *reg_grp_node = *child_node;
+       struct i2c_client *client = iqs7222->client;
+       char reg_grp_name[16];
+       int i;
+
+       switch (reg_grp) {
+       case IQS7222_REG_GRP_CYCLE:
+       case IQS7222_REG_GRP_CHAN:
+       case IQS7222_REG_GRP_SLDR:
+       case IQS7222_REG_GRP_GPIO:
+       case IQS7222_REG_GRP_BTN:
+               /*
+                * These groups derive a child node and return it to the caller
+                * for additional group-specific processing. In some cases, the
+                * child node may have already been derived.
+                */
+               if (*child_node)
+                       break;
+
+               snprintf(reg_grp_name, sizeof(reg_grp_name), "%s-%d",
+                        iqs7222_reg_grp_names[reg_grp], child_index);
+
+               reg_grp_node = device_get_named_child_node(&client->dev,
+                                                          reg_grp_name);
+               if (!reg_grp_node)
+                       return 0;
+
+               *child_node = reg_grp_node;
+               break;
+
+       case IQS7222_REG_GRP_GLBL:
+       case IQS7222_REG_GRP_FILT:
+       case IQS7222_REG_GRP_SYS:
+               /*
+                * These groups are not organized beneath a child node, nor are
+                * they subject to any additional processing by the caller.
+                */
+               reg_grp_node = dev_fwnode(&client->dev);
+               break;
+
+       default:
+               return -EINVAL;
+       }
+
+       for (i = 0; i < ARRAY_SIZE(iqs7222_props); i++) {
+               const char *name = iqs7222_props[i].name;
+               int reg_offset = iqs7222_props[i].reg_offset;
+               int reg_shift = iqs7222_props[i].reg_shift;
+               int reg_width = iqs7222_props[i].reg_width;
+               int val_pitch = iqs7222_props[i].val_pitch ? : 1;
+               int val_min = iqs7222_props[i].val_min;
+               int val_max = iqs7222_props[i].val_max;
+               bool invert = iqs7222_props[i].invert;
+               const char *label = iqs7222_props[i].label ? : name;
+               unsigned int val;
+               int error;
+
+               if (iqs7222_props[i].reg_grp != reg_grp ||
+                   iqs7222_props[i].reg_key != reg_key)
+                       continue;
+
+               /*
+                * Boolean register fields are one bit wide; they are forcibly
+                * reset to provide a means to undo changes by a bootloader if
+                * necessary.
+                *
+                * Scalar fields, on the other hand, are left untouched unless
+                * their corresponding properties are present.
+                */
+               if (reg_width == 1) {
+                       if (invert)
+                               setup[reg_offset] |= BIT(reg_shift);
+                       else
+                               setup[reg_offset] &= ~BIT(reg_shift);
+               }
+
+               if (!fwnode_property_present(reg_grp_node, name))
+                       continue;
+
+               if (reg_width == 1) {
+                       if (invert)
+                               setup[reg_offset] &= ~BIT(reg_shift);
+                       else
+                               setup[reg_offset] |= BIT(reg_shift);
+
+                       continue;
+               }
+
+               error = fwnode_property_read_u32(reg_grp_node, name, &val);
+               if (error) {
+                       dev_err(&client->dev, "Failed to read %s %s: %d\n",
+                               fwnode_get_name(reg_grp_node), label, error);
+                       return error;
+               }
+
+               if (!val_max)
+                       val_max = GENMASK(reg_width - 1, 0) * val_pitch;
+
+               if (val < val_min || val > val_max) {
+                       dev_err(&client->dev, "Invalid %s %s: %u\n",
+                               fwnode_get_name(reg_grp_node), label, val);
+                       return -EINVAL;
+               }
+
+               setup[reg_offset] &= ~GENMASK(reg_shift + reg_width - 1,
+                                             reg_shift);
+               setup[reg_offset] |= (val / val_pitch << reg_shift);
+       }
+
+       return 0;
+}
+
+static int iqs7222_parse_cycle(struct iqs7222_private *iqs7222, int cycle_index)
+{
+       u16 *cycle_setup = iqs7222->cycle_setup[cycle_index];
+       struct i2c_client *client = iqs7222->client;
+       struct fwnode_handle *cycle_node = NULL;
+       unsigned int pins[9];
+       int error, count, i;
+
+       /*
+        * Each channel shares a cycle with one other channel; the mapping of
+        * channels to cycles is fixed. Properties defined for a cycle impact
+        * both channels tied to the cycle.
+        */
+       error = iqs7222_parse_props(iqs7222, &cycle_node, cycle_index,
+                                   IQS7222_REG_GRP_CYCLE,
+                                   IQS7222_REG_KEY_NONE);
+       if (error)
+               return error;
+
+       if (!cycle_node)
+               return 0;
+
+       /*
+        * Unlike channels which are restricted to a select range of CRx pins
+        * based on channel number, any cycle can claim any of the device's 9
+        * CTx pins (CTx0-8).
+        */
+       if (!fwnode_property_present(cycle_node, "azoteq,tx-enable"))
+               return 0;
+
+       count = fwnode_property_count_u32(cycle_node, "azoteq,tx-enable");
+       if (count > ARRAY_SIZE(pins)) {
+               dev_err(&client->dev, "Invalid number of %s CTx pins\n",
+                       fwnode_get_name(cycle_node));
+               return -EINVAL;
+       } else if (count < 0) {
+               dev_err(&client->dev, "Failed to count %s CTx pins: %d\n",
+                       fwnode_get_name(cycle_node), count);
+               return count;
+       }
+
+       error = fwnode_property_read_u32_array(cycle_node, "azoteq,tx-enable",
+                                              pins, count);
+       if (error) {
+               dev_err(&client->dev, "Failed to read %s CTx pins: %d\n",
+                       fwnode_get_name(cycle_node), error);
+               return error;
+       }
+
+       cycle_setup[1] &= ~GENMASK(7 + ARRAY_SIZE(pins) - 1, 7);
+
+       for (i = 0; i < count; i++) {
+               if (pins[i] > 8) {
+                       dev_err(&client->dev, "Invalid %s CTx pin: %u\n",
+                               fwnode_get_name(cycle_node), pins[i]);
+                       return -EINVAL;
+               }
+
+               cycle_setup[1] |= BIT(pins[i] + 7);
+       }
+
+       return 0;
+}
+
+static int iqs7222_parse_chan(struct iqs7222_private *iqs7222, int chan_index)
+{
+       const struct iqs7222_dev_desc *dev_desc = iqs7222->dev_desc;
+       struct i2c_client *client = iqs7222->client;
+       struct fwnode_handle *chan_node = NULL;
+       int num_chan = dev_desc->reg_grps[IQS7222_REG_GRP_CHAN].num_row;
+       int ext_chan = rounddown(num_chan, 10);
+       int error, i;
+       u16 *chan_setup = iqs7222->chan_setup[chan_index];
+       u16 *sys_setup = iqs7222->sys_setup;
+       unsigned int val;
+
+       error = iqs7222_parse_props(iqs7222, &chan_node, chan_index,
+                                   IQS7222_REG_GRP_CHAN,
+                                   IQS7222_REG_KEY_NONE);
+       if (error)
+               return error;
+
+       if (!chan_node)
+               return 0;
+
+       if (dev_desc->allow_offset) {
+               sys_setup[dev_desc->allow_offset] |= BIT(chan_index);
+               if (fwnode_property_present(chan_node, "azoteq,ulp-allow"))
+                       sys_setup[dev_desc->allow_offset] &= ~BIT(chan_index);
+       }
+
+       chan_setup[0] |= IQS7222_CHAN_SETUP_0_CHAN_EN;
+
+       /*
+        * The reference channel function allows for differential measurements
+        * and is only available in the case of IQS7222A or IQS7222C.
+        */
+       if (dev_desc->reg_grps[IQS7222_REG_GRP_CHAN].num_col > 4 &&
+           fwnode_property_present(chan_node, "azoteq,ref-select")) {
+               u16 *ref_setup;
+
+               error = fwnode_property_read_u32(chan_node, "azoteq,ref-select",
+                                                &val);
+               if (error) {
+                       dev_err(&client->dev,
+                               "Failed to read %s reference channel: %d\n",
+                               fwnode_get_name(chan_node), error);
+                       return error;
+               }
+
+               if (val >= ext_chan) {
+                       dev_err(&client->dev,
+                               "Invalid %s reference channel: %u\n",
+                               fwnode_get_name(chan_node), val);
+                       return -EINVAL;
+               }
+
+               ref_setup = iqs7222->chan_setup[val];
+
+               /*
+                * Configure the current channel as a follower of the selected
+                * reference channel.
+                */
+               chan_setup[0] |= IQS7222_CHAN_SETUP_0_REF_MODE_FOLLOW;
+               chan_setup[4] = val * 42 + 1048;
+
+               if (!fwnode_property_read_u32(chan_node, "azoteq,ref-weight",
+                                             &val)) {
+                       if (val > U16_MAX) {
+                               dev_err(&client->dev,
+                                       "Invalid %s reference weight: %u\n",
+                                       fwnode_get_name(chan_node), val);
+                               return -EINVAL;
+                       }
+
+                       chan_setup[5] = val;
+               }
+
+               /*
+                * Configure the selected channel as a reference channel which
+                * serves the current channel.
+                */
+               ref_setup[0] |= IQS7222_CHAN_SETUP_0_REF_MODE_REF;
+               ref_setup[5] |= BIT(chan_index);
+
+               ref_setup[4] = dev_desc->touch_link;
+               if (fwnode_property_present(chan_node, "azoteq,use-prox"))
+                       ref_setup[4] -= 2;
+       }
+
+       if (fwnode_property_present(chan_node, "azoteq,rx-enable")) {
+               /*
+                * Each channel can claim up to 4 CRx pins. The first half of
+                * the channels can use CRx0-3, while the second half can use
+                * CRx4-7.
+                */
+               unsigned int pins[4];
+               int count;
+
+               count = fwnode_property_count_u32(chan_node,
+                                                 "azoteq,rx-enable");
+               if (count > ARRAY_SIZE(pins)) {
+                       dev_err(&client->dev,
+                               "Invalid number of %s CRx pins\n",
+                               fwnode_get_name(chan_node));
+                       return -EINVAL;
+               } else if (count < 0) {
+                       dev_err(&client->dev,
+                               "Failed to count %s CRx pins: %d\n",
+                               fwnode_get_name(chan_node), count);
+                       return count;
+               }
+
+               error = fwnode_property_read_u32_array(chan_node,
+                                                      "azoteq,rx-enable",
+                                                      pins, count);
+               if (error) {
+                       dev_err(&client->dev,
+                               "Failed to read %s CRx pins: %d\n",
+                               fwnode_get_name(chan_node), error);
+                       return error;
+               }
+
+               chan_setup[0] &= ~GENMASK(4 + ARRAY_SIZE(pins) - 1, 4);
+
+               for (i = 0; i < count; i++) {
+                       int min_crx = chan_index < ext_chan / 2 ? 0 : 4;
+
+                       if (pins[i] < min_crx || pins[i] > min_crx + 3) {
+                               dev_err(&client->dev,
+                                       "Invalid %s CRx pin: %u\n",
+                                       fwnode_get_name(chan_node), pins[i]);
+                               return -EINVAL;
+                       }
+
+                       chan_setup[0] |= BIT(pins[i] + 4 - min_crx);
+               }
+       }
+
+       for (i = 0; i < ARRAY_SIZE(iqs7222_kp_events); i++) {
+               const char *event_name = iqs7222_kp_events[i].name;
+               u16 event_enable = iqs7222_kp_events[i].enable;
+               struct fwnode_handle *event_node;
+
+               event_node = fwnode_get_named_child_node(chan_node, event_name);
+               if (!event_node)
+                       continue;
+
+               error = iqs7222_parse_props(iqs7222, &event_node, chan_index,
+                                           IQS7222_REG_GRP_BTN,
+                                           iqs7222_kp_events[i].reg_key);
+               if (error)
+                       return error;
+
+               error = iqs7222_gpio_select(iqs7222, event_node,
+                                           BIT(chan_index),
+                                           dev_desc->touch_link - (i ? 0 : 2));
+               if (error)
+                       return error;
+
+               if (!fwnode_property_read_u32(event_node,
+                                             "azoteq,timeout-press-ms",
+                                             &val)) {
+                       /*
+                        * The IQS7222B employs a global pair of press timeout
+                        * registers as opposed to channel-specific registers.
+                        */
+                       u16 *setup = dev_desc->reg_grps
+                                    [IQS7222_REG_GRP_BTN].num_col > 2 ?
+                                    &iqs7222->btn_setup[chan_index][2] :
+                                    &sys_setup[9];
+
+                       if (val > U8_MAX * 500) {
+                               dev_err(&client->dev,
+                                       "Invalid %s press timeout: %u\n",
+                                       fwnode_get_name(chan_node), val);
+                               return -EINVAL;
+                       }
+
+                       *setup &= ~(U8_MAX << i * 8);
+                       *setup |= (val / 500 << i * 8);
+               }
+
+               error = fwnode_property_read_u32(event_node, "linux,code",
+                                                &val);
+               if (error) {
+                       dev_err(&client->dev, "Failed to read %s code: %d\n",
+                               fwnode_get_name(chan_node), error);
+                       return error;
+               }
+
+               iqs7222->kp_code[chan_index][i] = val;
+               iqs7222->kp_type[chan_index][i] = EV_KEY;
+
+               if (fwnode_property_present(event_node, "linux,input-type")) {
+                       error = fwnode_property_read_u32(event_node,
+                                                        "linux,input-type",
+                                                        &val);
+                       if (error) {
+                               dev_err(&client->dev,
+                                       "Failed to read %s input type: %d\n",
+                                       fwnode_get_name(chan_node), error);
+                               return error;
+                       }
+
+                       if (val != EV_KEY && val != EV_SW) {
+                               dev_err(&client->dev,
+                                       "Invalid %s input type: %u\n",
+                                       fwnode_get_name(chan_node), val);
+                               return -EINVAL;
+                       }
+
+                       iqs7222->kp_type[chan_index][i] = val;
+               }
+
+               /*
+                * Reference channels can opt out of event reporting by using
+                * KEY_RESERVED in place of a true key or switch code.
+                */
+               if (iqs7222->kp_type[chan_index][i] == EV_KEY &&
+                   iqs7222->kp_code[chan_index][i] == KEY_RESERVED)
+                       continue;
+
+               input_set_capability(iqs7222->keypad,
+                                    iqs7222->kp_type[chan_index][i],
+                                    iqs7222->kp_code[chan_index][i]);
+
+               if (!dev_desc->event_offset)
+                       continue;
+
+               sys_setup[dev_desc->event_offset] |= event_enable;
+       }
+
+       /*
+        * The following call handles a special pair of properties that apply
+        * to a channel node, but reside within the button (event) group.
+        */
+       return iqs7222_parse_props(iqs7222, &chan_node, chan_index,
+                                  IQS7222_REG_GRP_BTN,
+                                  IQS7222_REG_KEY_DEBOUNCE);
+}
+
+static int iqs7222_parse_sldr(struct iqs7222_private *iqs7222, int sldr_index)
+{
+       const struct iqs7222_dev_desc *dev_desc = iqs7222->dev_desc;
+       struct i2c_client *client = iqs7222->client;
+       struct fwnode_handle *sldr_node = NULL;
+       int num_chan = dev_desc->reg_grps[IQS7222_REG_GRP_CHAN].num_row;
+       int ext_chan = rounddown(num_chan, 10);
+       int count, error, reg_offset, i;
+       u16 *sldr_setup = iqs7222->sldr_setup[sldr_index];
+       u16 *sys_setup = iqs7222->sys_setup;
+       unsigned int chan_sel[4], val;
+
+       error = iqs7222_parse_props(iqs7222, &sldr_node, sldr_index,
+                                   IQS7222_REG_GRP_SLDR,
+                                   IQS7222_REG_KEY_NONE);
+       if (error)
+               return error;
+
+       if (!sldr_node)
+               return 0;
+
+       /*
+        * Each slider can be spread across 3 to 4 channels. It is possible to
+        * select only 2 channels, but doing so prevents the slider from using
+        * the specified resolution.
+        */
+       count = fwnode_property_count_u32(sldr_node, "azoteq,channel-select");
+       if (count < 3 || count > ARRAY_SIZE(chan_sel)) {
+               dev_err(&client->dev, "Invalid number of %s channels\n",
+                       fwnode_get_name(sldr_node));
+               return -EINVAL;
+       } else if (count < 0) {
+               dev_err(&client->dev, "Failed to count %s channels: %d\n",
+                       fwnode_get_name(sldr_node), count);
+               return count;
+       }
+
+       error = fwnode_property_read_u32_array(sldr_node,
+                                              "azoteq,channel-select",
+                                              chan_sel, count);
+       if (error) {
+               dev_err(&client->dev, "Failed to read %s channels: %d\n",
+                       fwnode_get_name(sldr_node), error);
+               return error;
+       }
+
+       /*
+        * Resolution and top speed, if small enough, are packed into a single
+        * register. Otherwise, each occupies its own register and the rest of
+        * the slider-related register addresses are offset by one.
+        */
+       reg_offset = dev_desc->sldr_res < U16_MAX ? 0 : 1;
+
+       sldr_setup[0] |= count;
+       sldr_setup[3 + reg_offset] &= ~IQS7222_SLDR_SETUP_3_CHAN_SEL_MASK;
+
+       for (i = 0; i < ARRAY_SIZE(chan_sel); i++) {
+               sldr_setup[5 + reg_offset + i] = 0;
+               if (i >= count)
+                       continue;
+
+               if (chan_sel[i] >= ext_chan) {
+                       dev_err(&client->dev, "Invalid %s channel: %u\n",
+                               fwnode_get_name(sldr_node), chan_sel[i]);
+                       return -EINVAL;
+               }
+
+               /*
+                * The following fields indicate which channels participate in
+                * the slider, as well as each channel's relative placement.
+                */
+               sldr_setup[3 + reg_offset] |= BIT(chan_sel[i]);
+               sldr_setup[5 + reg_offset + i] = chan_sel[i] * 42 + 1080;
+       }
+
+       sldr_setup[4 + reg_offset] = dev_desc->touch_link;
+       if (fwnode_property_present(sldr_node, "azoteq,use-prox"))
+               sldr_setup[4 + reg_offset] -= 2;
+
+       if (!fwnode_property_read_u32(sldr_node, "azoteq,slider-size", &val)) {
+               if (!val || val > dev_desc->sldr_res) {
+                       dev_err(&client->dev, "Invalid %s size: %u\n",
+                               fwnode_get_name(sldr_node), val);
+                       return -EINVAL;
+               }
+
+               if (reg_offset) {
+                       sldr_setup[3] = val;
+               } else {
+                       sldr_setup[2] &= ~IQS7222_SLDR_SETUP_2_RES_MASK;
+                       sldr_setup[2] |= (val / 16 <<
+                                         IQS7222_SLDR_SETUP_2_RES_SHIFT);
+               }
+       }
+
+       if (!fwnode_property_read_u32(sldr_node, "azoteq,top-speed", &val)) {
+               if (val > (reg_offset ? U16_MAX : U8_MAX * 4)) {
+                       dev_err(&client->dev, "Invalid %s top speed: %u\n",
+                               fwnode_get_name(sldr_node), val);
+                       return -EINVAL;
+               }
+
+               if (reg_offset) {
+                       sldr_setup[2] = val;
+               } else {
+                       sldr_setup[2] &= ~IQS7222_SLDR_SETUP_2_TOP_SPEED_MASK;
+                       sldr_setup[2] |= (val / 4);
+               }
+       }
+
+       if (!fwnode_property_read_u32(sldr_node, "linux,axis", &val)) {
+               u16 sldr_max = sldr_setup[3] - 1;
+
+               if (!reg_offset) {
+                       sldr_max = sldr_setup[2];
+
+                       sldr_max &= IQS7222_SLDR_SETUP_2_RES_MASK;
+                       sldr_max >>= IQS7222_SLDR_SETUP_2_RES_SHIFT;
+
+                       sldr_max = sldr_max * 16 - 1;
+               }
+
+               input_set_abs_params(iqs7222->keypad, val, 0, sldr_max, 0, 0);
+               iqs7222->sl_axis[sldr_index] = val;
+       }
+
+       if (dev_desc->wheel_enable) {
+               sldr_setup[0] &= ~dev_desc->wheel_enable;
+               if (iqs7222->sl_axis[sldr_index] == ABS_WHEEL)
+                       sldr_setup[0] |= dev_desc->wheel_enable;
+       }
+
+       for (i = 0; i < ARRAY_SIZE(iqs7222_sl_events); i++) {
+               const char *event_name = iqs7222_sl_events[i].name;
+               struct fwnode_handle *event_node;
+
+               /*
+                * The absence of a register offset means the remaining fields
+                * in the group represent gesture settings.
+                */
+               if (iqs7222_sl_events[i].enable && !reg_offset)
+                       sldr_setup[9] &= ~iqs7222_sl_events[i].enable;
+
+               event_node = fwnode_get_named_child_node(sldr_node, event_name);
+               if (!event_node)
+                       continue;
+
+               error = iqs7222_parse_props(iqs7222, &event_node, sldr_index,
+                                           IQS7222_REG_GRP_SLDR,
+                                           reg_offset ?
+                                           IQS7222_REG_KEY_RESERVED :
+                                           iqs7222_sl_events[i].reg_key);
+               if (error)
+                       return error;
+
+               error = fwnode_property_read_u32(event_node, "linux,code",
+                                                &val);
+               if (error) {
+                       dev_err(&client->dev, "Failed to read %s code: %d\n",
+                               fwnode_get_name(sldr_node), error);
+                       return error;
+               }
+
+               iqs7222->sl_code[sldr_index][i] = val;
+               input_set_capability(iqs7222->keypad, EV_KEY, val);
+
+               /*
+                * The press/release event is determined based on whether the
+                * coordinate field reports 0xFFFF and has no explicit enable
+                * control.
+                */
+               if (!iqs7222_sl_events[i].enable || reg_offset)
+                       continue;
+
+               sldr_setup[9] |= iqs7222_sl_events[i].enable;
+
+               error = iqs7222_gpio_select(iqs7222, event_node,
+                                           iqs7222_sl_events[i].enable,
+                                           1568 + sldr_index * 30);
+               if (error)
+                       return error;
+
+               if (!dev_desc->event_offset)
+                       continue;
+
+               sys_setup[dev_desc->event_offset] |= BIT(10 + sldr_index);
+       }
+
+       /*
+        * The following call handles a special pair of properties that shift
+        * to make room for a wheel enable control in the case of IQS7222C.
+        */
+       return iqs7222_parse_props(iqs7222, &sldr_node, sldr_index,
+                                  IQS7222_REG_GRP_SLDR,
+                                  dev_desc->wheel_enable ?
+                                  IQS7222_REG_KEY_WHEEL :
+                                  IQS7222_REG_KEY_NO_WHEEL);
+}
+
+static int iqs7222_parse_all(struct iqs7222_private *iqs7222)
+{
+       const struct iqs7222_dev_desc *dev_desc = iqs7222->dev_desc;
+       const struct iqs7222_reg_grp_desc *reg_grps = dev_desc->reg_grps;
+       u16 *sys_setup = iqs7222->sys_setup;
+       int error, i;
+
+       if (dev_desc->event_offset)
+               sys_setup[dev_desc->event_offset] = IQS7222_EVENT_MASK_ATI;
+
+       for (i = 0; i < reg_grps[IQS7222_REG_GRP_CYCLE].num_row; i++) {
+               error = iqs7222_parse_cycle(iqs7222, i);
+               if (error)
+                       return error;
+       }
+
+       error = iqs7222_parse_props(iqs7222, NULL, 0, IQS7222_REG_GRP_GLBL,
+                                   IQS7222_REG_KEY_NONE);
+       if (error)
+               return error;
+
+       for (i = 0; i < reg_grps[IQS7222_REG_GRP_GPIO].num_row; i++) {
+               struct fwnode_handle *gpio_node = NULL;
+               u16 *gpio_setup = iqs7222->gpio_setup[i];
+               int j;
+
+               gpio_setup[0] &= ~IQS7222_GPIO_SETUP_0_GPIO_EN;
+               gpio_setup[1] = 0;
+               gpio_setup[2] = 0;
+
+               error = iqs7222_parse_props(iqs7222, &gpio_node, i,
+                                           IQS7222_REG_GRP_GPIO,
+                                           IQS7222_REG_KEY_NONE);
+               if (error)
+                       return error;
+
+               if (reg_grps[IQS7222_REG_GRP_GPIO].num_row == 1)
+                       continue;
+
+               /*
+                * The IQS7222C exposes multiple GPIO and must be informed
+                * as to which GPIO this group represents.
+                */
+               for (j = 0; j < ARRAY_SIZE(iqs7222_gpio_links); j++)
+                       gpio_setup[0] &= ~BIT(iqs7222_gpio_links[j]);
+
+               gpio_setup[0] |= BIT(iqs7222_gpio_links[i]);
+       }
+
+       for (i = 0; i < reg_grps[IQS7222_REG_GRP_CHAN].num_row; i++) {
+               u16 *chan_setup = iqs7222->chan_setup[i];
+
+               chan_setup[0] &= ~IQS7222_CHAN_SETUP_0_REF_MODE_MASK;
+               chan_setup[0] &= ~IQS7222_CHAN_SETUP_0_CHAN_EN;
+
+               chan_setup[5] = 0;
+       }
+
+       for (i = 0; i < reg_grps[IQS7222_REG_GRP_CHAN].num_row; i++) {
+               error = iqs7222_parse_chan(iqs7222, i);
+               if (error)
+                       return error;
+       }
+
+       error = iqs7222_parse_props(iqs7222, NULL, 0, IQS7222_REG_GRP_FILT,
+                                   IQS7222_REG_KEY_NONE);
+       if (error)
+               return error;
+
+       for (i = 0; i < reg_grps[IQS7222_REG_GRP_SLDR].num_row; i++) {
+               u16 *sldr_setup = iqs7222->sldr_setup[i];
+
+               sldr_setup[0] &= ~IQS7222_SLDR_SETUP_0_CHAN_CNT_MASK;
+
+               error = iqs7222_parse_sldr(iqs7222, i);
+               if (error)
+                       return error;
+       }
+
+       sys_setup[0] &= ~IQS7222_SYS_SETUP_INTF_MODE_MASK;
+       sys_setup[0] &= ~IQS7222_SYS_SETUP_PWR_MODE_MASK;
+
+       sys_setup[0] |= IQS7222_SYS_SETUP_ACK_RESET;
+
+       return iqs7222_parse_props(iqs7222, NULL, 0, IQS7222_REG_GRP_SYS,
+                                  IQS7222_REG_KEY_NONE);
+}
+
+static int iqs7222_report(struct iqs7222_private *iqs7222)
+{
+       const struct iqs7222_dev_desc *dev_desc = iqs7222->dev_desc;
+       struct i2c_client *client = iqs7222->client;
+       int num_chan = dev_desc->reg_grps[IQS7222_REG_GRP_CHAN].num_row;
+       int num_stat = dev_desc->reg_grps[IQS7222_REG_GRP_STAT].num_col;
+       int error, i, j;
+       __le16 status[IQS7222_MAX_COLS_STAT];
+
+       error = iqs7222_read_burst(iqs7222, IQS7222_SYS_STATUS, status,
+                                  num_stat);
+       if (error)
+               return error;
+
+       if (le16_to_cpu(status[0]) & IQS7222_SYS_STATUS_RESET) {
+               dev_err(&client->dev, "Unexpected device reset\n");
+               return iqs7222_dev_init(iqs7222, WRITE);
+       }
+
+       if (le16_to_cpu(status[0]) & IQS7222_SYS_STATUS_ATI_ERROR) {
+               dev_err(&client->dev, "Unexpected ATI error\n");
+               return iqs7222_ati_trigger(iqs7222);
+       }
+
+       if (le16_to_cpu(status[0]) & IQS7222_SYS_STATUS_ATI_ACTIVE)
+               return 0;
+
+       for (i = 0; i < num_chan; i++) {
+               u16 *chan_setup = iqs7222->chan_setup[i];
+
+               if (!(chan_setup[0] & IQS7222_CHAN_SETUP_0_CHAN_EN))
+                       continue;
+
+               for (j = 0; j < ARRAY_SIZE(iqs7222_kp_events); j++) {
+                       /*
+                        * Proximity state begins at offset 2 and spills into
+                        * offset 3 for devices with more than 16 channels.
+                        *
+                        * Touch state begins at the first offset immediately
+                        * following proximity state.
+                        */
+                       int k = 2 + j * (num_chan > 16 ? 2 : 1);
+                       u16 state = le16_to_cpu(status[k + i / 16]);
+
+                       input_event(iqs7222->keypad,
+                                   iqs7222->kp_type[i][j],
+                                   iqs7222->kp_code[i][j],
+                                   !!(state & BIT(i % 16)));
+               }
+       }
+
+       for (i = 0; i < dev_desc->reg_grps[IQS7222_REG_GRP_SLDR].num_row; i++) {
+               u16 *sldr_setup = iqs7222->sldr_setup[i];
+               u16 sldr_pos = le16_to_cpu(status[4 + i]);
+               u16 state = le16_to_cpu(status[6 + i]);
+
+               if (!(sldr_setup[0] & IQS7222_SLDR_SETUP_0_CHAN_CNT_MASK))
+                       continue;
+
+               if (sldr_pos < dev_desc->sldr_res)
+                       input_report_abs(iqs7222->keypad, iqs7222->sl_axis[i],
+                                        sldr_pos);
+
+               for (j = 0; j < ARRAY_SIZE(iqs7222_sl_events); j++) {
+                       u16 mask = iqs7222_sl_events[j].mask;
+                       u16 val = iqs7222_sl_events[j].val;
+
+                       if (!iqs7222_sl_events[j].enable) {
+                               input_report_key(iqs7222->keypad,
+                                                iqs7222->sl_code[i][j],
+                                                sldr_pos < dev_desc->sldr_res);
+                               continue;
+                       }
+
+                       /*
+                        * The remaining offsets represent gesture state, and
+                        * are discarded in the case of IQS7222C because only
+                        * absolute position is reported.
+                        */
+                       if (num_stat < IQS7222_MAX_COLS_STAT)
+                               continue;
+
+                       input_report_key(iqs7222->keypad,
+                                        iqs7222->sl_code[i][j],
+                                        (state & mask) == val);
+               }
+       }
+
+       input_sync(iqs7222->keypad);
+
+       return 0;
+}
+
+static irqreturn_t iqs7222_irq(int irq, void *context)
+{
+       struct iqs7222_private *iqs7222 = context;
+
+       return iqs7222_report(iqs7222) ? IRQ_NONE : IRQ_HANDLED;
+}
+
+static int iqs7222_probe(struct i2c_client *client)
+{
+       struct iqs7222_private *iqs7222;
+       unsigned long irq_flags;
+       int error, irq;
+
+       iqs7222 = devm_kzalloc(&client->dev, sizeof(*iqs7222), GFP_KERNEL);
+       if (!iqs7222)
+               return -ENOMEM;
+
+       i2c_set_clientdata(client, iqs7222);
+       iqs7222->client = client;
+
+       iqs7222->keypad = devm_input_allocate_device(&client->dev);
+       if (!iqs7222->keypad)
+               return -ENOMEM;
+
+       iqs7222->keypad->name = client->name;
+       iqs7222->keypad->id.bustype = BUS_I2C;
+
+       /*
+        * The RDY pin behaves as an interrupt, but must also be polled ahead
+        * of unsolicited I2C communication. As such, it is first opened as a
+        * GPIO and then passed to gpiod_to_irq() to register the interrupt.
+        */
+       iqs7222->irq_gpio = devm_gpiod_get(&client->dev, "irq", GPIOD_IN);
+       if (IS_ERR(iqs7222->irq_gpio)) {
+               error = PTR_ERR(iqs7222->irq_gpio);
+               dev_err(&client->dev, "Failed to request IRQ GPIO: %d\n",
+                       error);
+               return error;
+       }
+
+       iqs7222->reset_gpio = devm_gpiod_get_optional(&client->dev, "reset",
+                                                     GPIOD_OUT_HIGH);
+       if (IS_ERR(iqs7222->reset_gpio)) {
+               error = PTR_ERR(iqs7222->reset_gpio);
+               dev_err(&client->dev, "Failed to request reset GPIO: %d\n",
+                       error);
+               return error;
+       }
+
+       error = iqs7222_hard_reset(iqs7222);
+       if (error)
+               return error;
+
+       error = iqs7222_dev_info(iqs7222);
+       if (error)
+               return error;
+
+       error = iqs7222_dev_init(iqs7222, READ);
+       if (error)
+               return error;
+
+       error = iqs7222_parse_all(iqs7222);
+       if (error)
+               return error;
+
+       error = iqs7222_dev_init(iqs7222, WRITE);
+       if (error)
+               return error;
+
+       error = iqs7222_report(iqs7222);
+       if (error)
+               return error;
+
+       error = input_register_device(iqs7222->keypad);
+       if (error) {
+               dev_err(&client->dev, "Failed to register device: %d\n", error);
+               return error;
+       }
+
+       irq = gpiod_to_irq(iqs7222->irq_gpio);
+       if (irq < 0)
+               return irq;
+
+       irq_flags = gpiod_is_active_low(iqs7222->irq_gpio) ? IRQF_TRIGGER_LOW
+                                                          : IRQF_TRIGGER_HIGH;
+       irq_flags |= IRQF_ONESHOT;
+
+       error = devm_request_threaded_irq(&client->dev, irq, NULL, iqs7222_irq,
+                                         irq_flags, client->name, iqs7222);
+       if (error)
+               dev_err(&client->dev, "Failed to request IRQ: %d\n", error);
+
+       return error;
+}
+
+static const struct of_device_id iqs7222_of_match[] = {
+       { .compatible = "azoteq,iqs7222a" },
+       { .compatible = "azoteq,iqs7222b" },
+       { .compatible = "azoteq,iqs7222c" },
+       { }
+};
+MODULE_DEVICE_TABLE(of, iqs7222_of_match);
+
+static struct i2c_driver iqs7222_i2c_driver = {
+       .driver = {
+               .name = "iqs7222",
+               .of_match_table = iqs7222_of_match,
+       },
+       .probe_new = iqs7222_probe,
+};
+module_i2c_driver(iqs7222_i2c_driver);
+
+MODULE_AUTHOR("Jeff LaBundy <jeff@labundy.com>");
+MODULE_DESCRIPTION("Azoteq IQS7222A/B/C Capacitive Touch Controller");
+MODULE_LICENSE("GPL");