--- /dev/null
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Rohm BU21029 touchscreen controller driver
+ *
+ * Copyright (C) 2015-2018 Bosch Sicherheitssysteme GmbH
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/delay.h>
+#include <linux/gpio/consumer.h>
+#include <linux/i2c.h>
+#include <linux/input.h>
+#include <linux/input/touchscreen.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/module.h>
+#include <linux/regulator/consumer.h>
+#include <linux/timer.h>
+
+/*
+ * HW_ID1 Register (PAGE=0, ADDR=0x0E, Reset value=0x02, Read only)
+ * +--------+--------+--------+--------+--------+--------+--------+--------+
+ * | D7 | D6 | D5 | D4 | D3 | D2 | D1 | D0 |
+ * +--------+--------+--------+--------+--------+--------+--------+--------+
+ * | HW_IDH |
+ * +--------+--------+--------+--------+--------+--------+--------+--------+
+ * HW_ID2 Register (PAGE=0, ADDR=0x0F, Reset value=0x29, Read only)
+ * +--------+--------+--------+--------+--------+--------+--------+--------+
+ * | D7 | D6 | D5 | D4 | D3 | D2 | D1 | D0 |
+ * +--------+--------+--------+--------+--------+--------+--------+--------+
+ * | HW_IDL |
+ * +--------+--------+--------+--------+--------+--------+--------+--------+
+ * HW_IDH: high 8bits of IC's ID
+ * HW_IDL: low 8bits of IC's ID
+ */
+#define BU21029_HWID_REG (0x0E << 3)
+#define SUPPORTED_HWID 0x0229
+
+/*
+ * CFR0 Register (PAGE=0, ADDR=0x00, Reset value=0x20)
+ * +--------+--------+--------+--------+--------+--------+--------+--------+
+ * | D7 | D6 | D5 | D4 | D3 | D2 | D1 | D0 |
+ * +--------+--------+--------+--------+--------+--------+--------+--------+
+ * | 0 | 0 | CALIB | INTRM | 0 | 0 | 0 | 0 |
+ * +--------+--------+--------+--------+--------+--------+--------+--------+
+ * CALIB: 0 = not to use calibration result (*)
+ * 1 = use calibration result
+ * INTRM: 0 = INT output depend on "pen down" (*)
+ * 1 = INT output always "0"
+ */
+#define BU21029_CFR0_REG (0x00 << 3)
+#define CFR0_VALUE 0x00
+
+/*
+ * CFR1 Register (PAGE=0, ADDR=0x01, Reset value=0xA6)
+ * +--------+--------+--------+--------+--------+--------+--------+--------+
+ * | D7 | D6 | D5 | D4 | D3 | D2 | D1 | D0 |
+ * +--------+--------+--------+--------+--------+--------+--------+--------+
+ * | MAV | AVE[2:0] | 0 | SMPL[2:0] |
+ * +--------+--------+--------+--------+--------+--------+--------+--------+
+ * MAV: 0 = median average filter off
+ * 1 = median average filter on (*)
+ * AVE: AVE+1 = number of average samples for MAV,
+ * if AVE>SMPL, then AVE=SMPL (=3)
+ * SMPL: SMPL+1 = number of conversion samples for MAV (=7)
+ */
+#define BU21029_CFR1_REG (0x01 << 3)
+#define CFR1_VALUE 0xA6
+
+/*
+ * CFR2 Register (PAGE=0, ADDR=0x02, Reset value=0x04)
+ * +--------+--------+--------+--------+--------+--------+--------+--------+
+ * | D7 | D6 | D5 | D4 | D3 | D2 | D1 | D0 |
+ * +--------+--------+--------+--------+--------+--------+--------+--------+
+ * | INTVL_TIME[3:0] | TIME_ST_ADC[3:0] |
+ * +--------+--------+--------+--------+--------+--------+--------+--------+
+ * INTVL_TIME: waiting time between completion of conversion
+ * and start of next conversion, only usable in
+ * autoscan mode (=20.480ms)
+ * TIME_ST_ADC: waiting time between application of voltage
+ * to panel and start of A/D conversion (=100us)
+ */
+#define BU21029_CFR2_REG (0x02 << 3)
+#define CFR2_VALUE 0xC9
+
+/*
+ * CFR3 Register (PAGE=0, ADDR=0x0B, Reset value=0x72)
+ * +--------+--------+--------+--------+--------+--------+--------+--------+
+ * | D7 | D6 | D5 | D4 | D3 | D2 | D1 | D0 |
+ * +--------+--------+--------+--------+--------+--------+--------+--------+
+ * | RM8 | STRETCH| PU90K | DUAL | PIDAC_OFS[3:0] |
+ * +--------+--------+--------+--------+--------+--------+--------+--------+
+ * RM8: 0 = coordinate resolution is 12bit (*)
+ * 1 = coordinate resolution is 8bit
+ * STRETCH: 0 = SCL_STRETCH function off
+ * 1 = SCL_STRETCH function on (*)
+ * PU90K: 0 = internal pull-up resistance for touch detection is ~50kohms (*)
+ * 1 = internal pull-up resistance for touch detection is ~90kohms
+ * DUAL: 0 = dual touch detection off (*)
+ * 1 = dual touch detection on
+ * PIDAC_OFS: dual touch detection circuit adjustment, it is not necessary
+ * to change this from initial value
+ */
+#define BU21029_CFR3_REG (0x0B << 3)
+#define CFR3_VALUE 0x42
+
+/*
+ * LDO Register (PAGE=0, ADDR=0x0C, Reset value=0x00)
+ * +--------+--------+--------+--------+--------+--------+--------+--------+
+ * | D7 | D6 | D5 | D4 | D3 | D2 | D1 | D0 |
+ * +--------+--------+--------+--------+--------+--------+--------+--------+
+ * | 0 | PVDD[2:0] | 0 | AVDD[2:0] |
+ * +--------+--------+--------+--------+--------+--------+--------+--------+
+ * PVDD: output voltage of panel output regulator (=2.000V)
+ * AVDD: output voltage of analog circuit regulator (=2.000V)
+ */
+#define BU21029_LDO_REG (0x0C << 3)
+#define LDO_VALUE 0x77
+
+/*
+ * Serial Interface Command Byte 1 (CID=1)
+ * +--------+--------+--------+--------+--------+--------+--------+--------+
+ * | D7 | D6 | D5 | D4 | D3 | D2 | D1 | D0 |
+ * +--------+--------+--------+--------+--------+--------+--------+--------+
+ * | 1 | CF | CMSK | PDM | STP |
+ * +--------+--------+--------+--------+--------+--------+--------+--------+
+ * CF: conversion function, see table 3 in datasheet p6 (=0000, automatic scan)
+ * CMSK: 0 = executes convert function (*)
+ * 1 = reads the convert result
+ * PDM: 0 = power down after convert function stops (*)
+ * 1 = keep power on after convert function stops
+ * STP: 1 = abort current conversion and power down, set to "0" automatically
+ */
+#define BU21029_AUTOSCAN 0x80
+
+/*
+ * The timeout value needs to be larger than INTVL_TIME + tConv4 (sample and
+ * conversion time), where tConv4 is calculated by formula:
+ * tPON + tDLY1 + (tTIME_ST_ADC + (tADC * tSMPL) * 2 + tDLY2) * 3
+ * see figure 8 in datasheet p15 for details of each field.
+ */
+#define PEN_UP_TIMEOUT_MS 50
+
+#define STOP_DELAY_MIN_US 50
+#define STOP_DELAY_MAX_US 1000
+#define START_DELAY_MS 2
+#define BUF_LEN 8
+#define SCALE_12BIT (1 << 12)
+#define MAX_12BIT ((1 << 12) - 1)
+#define DRIVER_NAME "bu21029"
+
+struct bu21029_ts_data {
+ struct i2c_client *client;
+ struct input_dev *in_dev;
+ struct timer_list timer;
+ struct regulator *vdd;
+ struct gpio_desc *reset_gpios;
+ u32 x_plate_ohms;
+ struct touchscreen_properties prop;
+};
+
+static void bu21029_touch_report(struct bu21029_ts_data *bu21029, const u8 *buf)
+{
+ u16 x, y, z1, z2;
+ u32 rz;
+ s32 max_pressure = input_abs_get_max(bu21029->in_dev, ABS_PRESSURE);
+
+ /*
+ * compose upper 8 and lower 4 bits into a 12bit value:
+ * +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
+ * | ByteH | ByteL |
+ * +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
+ * |b07|b06|b05|b04|b03|b02|b01|b00|b07|b06|b05|b04|b03|b02|b01|b00|
+ * +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
+ * |v11|v10|v09|v08|v07|v06|v05|v04|v03|v02|v01|v00| 0 | 0 | 0 | 0 |
+ * +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
+ */
+ x = (buf[0] << 4) | (buf[1] >> 4);
+ y = (buf[2] << 4) | (buf[3] >> 4);
+ z1 = (buf[4] << 4) | (buf[5] >> 4);
+ z2 = (buf[6] << 4) | (buf[7] >> 4);
+
+ if (z1 && z2) {
+ /*
+ * calculate Rz (pressure resistance value) by equation:
+ * Rz = Rx * (x/Q) * ((z2/z1) - 1), where
+ * Rx is x-plate resistance,
+ * Q is the touch screen resolution (8bit = 256, 12bit = 4096)
+ * x, z1, z2 are the measured positions.
+ */
+ rz = z2 - z1;
+ rz *= x;
+ rz *= bu21029->x_plate_ohms;
+ rz /= z1;
+ rz = DIV_ROUND_CLOSEST(rz, SCALE_12BIT);
+ if (rz <= max_pressure) {
+ touchscreen_report_pos(bu21029->in_dev, &bu21029->prop,
+ x, y, false);
+ input_report_abs(bu21029->in_dev, ABS_PRESSURE,
+ max_pressure - rz);
+ input_report_key(bu21029->in_dev, BTN_TOUCH, 1);
+ input_sync(bu21029->in_dev);
+ }
+ }
+}
+
+static void bu21029_touch_release(struct timer_list *t)
+{
+ struct bu21029_ts_data *bu21029 = from_timer(bu21029, t, timer);
+
+ input_report_abs(bu21029->in_dev, ABS_PRESSURE, 0);
+ input_report_key(bu21029->in_dev, BTN_TOUCH, 0);
+ input_sync(bu21029->in_dev);
+}
+
+static irqreturn_t bu21029_touch_soft_irq(int irq, void *data)
+{
+ struct bu21029_ts_data *bu21029 = data;
+ u8 buf[BUF_LEN];
+ int error;
+
+ /*
+ * Read touch data and deassert interrupt (will assert again after
+ * INTVL_TIME + tConv4 for continuous touch)
+ */
+ error = i2c_smbus_read_i2c_block_data(bu21029->client, BU21029_AUTOSCAN,
+ sizeof(buf), buf);
+ if (error < 0)
+ goto out;
+
+ bu21029_touch_report(bu21029, buf);
+
+ /* reset timer for pen up detection */
+ mod_timer(&bu21029->timer,
+ jiffies + msecs_to_jiffies(PEN_UP_TIMEOUT_MS));
+
+out:
+ return IRQ_HANDLED;
+}
+
+static void bu21029_put_chip_in_reset(struct bu21029_ts_data *bu21029)
+{
+ if (bu21029->reset_gpios) {
+ gpiod_set_value_cansleep(bu21029->reset_gpios, 1);
+ usleep_range(STOP_DELAY_MIN_US, STOP_DELAY_MAX_US);
+ }
+}
+
+static int bu21029_start_chip(struct input_dev *dev)
+{
+ struct bu21029_ts_data *bu21029 = input_get_drvdata(dev);
+ struct i2c_client *i2c = bu21029->client;
+ struct {
+ u8 reg;
+ u8 value;
+ } init_table[] = {
+ {BU21029_CFR0_REG, CFR0_VALUE},
+ {BU21029_CFR1_REG, CFR1_VALUE},
+ {BU21029_CFR2_REG, CFR2_VALUE},
+ {BU21029_CFR3_REG, CFR3_VALUE},
+ {BU21029_LDO_REG, LDO_VALUE}
+ };
+ int error, i;
+ __be16 hwid;
+
+ error = regulator_enable(bu21029->vdd);
+ if (error) {
+ dev_err(&i2c->dev, "failed to power up chip: %d", error);
+ return error;
+ }
+
+ /* take chip out of reset */
+ if (bu21029->reset_gpios) {
+ gpiod_set_value_cansleep(bu21029->reset_gpios, 0);
+ msleep(START_DELAY_MS);
+ }
+
+ error = i2c_smbus_read_i2c_block_data(i2c, BU21029_HWID_REG,
+ sizeof(hwid), (u8 *)&hwid);
+ if (error < 0) {
+ dev_err(&i2c->dev, "failed to read HW ID\n");
+ goto err_out;
+ }
+
+ if (be16_to_cpu(hwid) != SUPPORTED_HWID) {
+ dev_err(&i2c->dev,
+ "unsupported HW ID 0x%x\n", be16_to_cpu(hwid));
+ error = -ENODEV;
+ goto err_out;
+ }
+
+ for (i = 0; i < ARRAY_SIZE(init_table); ++i) {
+ error = i2c_smbus_write_byte_data(i2c,
+ init_table[i].reg,
+ init_table[i].value);
+ if (error < 0) {
+ dev_err(&i2c->dev,
+ "failed to write %#02x to register %#02x: %d\n",
+ init_table[i].value, init_table[i].reg,
+ error);
+ goto err_out;
+ }
+ }
+
+ error = i2c_smbus_write_byte(i2c, BU21029_AUTOSCAN);
+ if (error < 0) {
+ dev_err(&i2c->dev, "failed to start autoscan\n");
+ goto err_out;
+ }
+
+ enable_irq(bu21029->client->irq);
+ return 0;
+
+err_out:
+ bu21029_put_chip_in_reset(bu21029);
+ regulator_disable(bu21029->vdd);
+ return error;
+}
+
+static void bu21029_stop_chip(struct input_dev *dev)
+{
+ struct bu21029_ts_data *bu21029 = input_get_drvdata(dev);
+
+ disable_irq(bu21029->client->irq);
+ del_timer_sync(&bu21029->timer);
+
+ bu21029_put_chip_in_reset(bu21029);
+ regulator_disable(bu21029->vdd);
+}
+
+static int bu21029_probe(struct i2c_client *client,
+ const struct i2c_device_id *id)
+{
+ struct bu21029_ts_data *bu21029;
+ struct input_dev *in_dev;
+ int error;
+
+ if (!i2c_check_functionality(client->adapter,
+ I2C_FUNC_SMBUS_WRITE_BYTE |
+ I2C_FUNC_SMBUS_WRITE_BYTE_DATA |
+ I2C_FUNC_SMBUS_READ_I2C_BLOCK)) {
+ dev_err(&client->dev,
+ "i2c functionality support is not sufficient\n");
+ return -EIO;
+ }
+
+ bu21029 = devm_kzalloc(&client->dev, sizeof(*bu21029), GFP_KERNEL);
+ if (!bu21029)
+ return -ENOMEM;
+
+ error = device_property_read_u32(&client->dev, "rohm,x-plate-ohms",
+ &bu21029->x_plate_ohms);
+ if (error) {
+ dev_err(&client->dev,
+ "invalid 'x-plate-ohms' supplied: %d\n", error);
+ return error;
+ }
+
+ bu21029->vdd = devm_regulator_get(&client->dev, "vdd");
+ if (IS_ERR(bu21029->vdd)) {
+ error = PTR_ERR(bu21029->vdd);
+ if (error != -EPROBE_DEFER)
+ dev_err(&client->dev,
+ "failed to acquire 'vdd' supply: %d\n", error);
+ return error;
+ }
+
+ bu21029->reset_gpios = devm_gpiod_get_optional(&client->dev,
+ "reset", GPIOD_OUT_HIGH);
+ if (IS_ERR(bu21029->reset_gpios)) {
+ error = PTR_ERR(bu21029->reset_gpios);
+ if (error != -EPROBE_DEFER)
+ dev_err(&client->dev,
+ "failed to acquire 'reset' gpio: %d\n", error);
+ return error;
+ }
+
+ in_dev = devm_input_allocate_device(&client->dev);
+ if (!in_dev) {
+ dev_err(&client->dev, "unable to allocate input device\n");
+ return -ENOMEM;
+ }
+
+ bu21029->client = client;
+ bu21029->in_dev = in_dev;
+ timer_setup(&bu21029->timer, bu21029_touch_release, 0);
+
+ in_dev->name = DRIVER_NAME;
+ in_dev->id.bustype = BUS_I2C;
+ in_dev->open = bu21029_start_chip;
+ in_dev->close = bu21029_stop_chip;
+
+ input_set_capability(in_dev, EV_KEY, BTN_TOUCH);
+ input_set_abs_params(in_dev, ABS_X, 0, MAX_12BIT, 0, 0);
+ input_set_abs_params(in_dev, ABS_Y, 0, MAX_12BIT, 0, 0);
+ input_set_abs_params(in_dev, ABS_PRESSURE, 0, MAX_12BIT, 0, 0);
+ touchscreen_parse_properties(in_dev, false, &bu21029->prop);
+
+ input_set_drvdata(in_dev, bu21029);
+
+ irq_set_status_flags(client->irq, IRQ_NOAUTOEN);
+ error = devm_request_threaded_irq(&client->dev, client->irq,
+ NULL, bu21029_touch_soft_irq,
+ IRQF_ONESHOT, DRIVER_NAME, bu21029);
+ if (error) {
+ dev_err(&client->dev,
+ "unable to request touch irq: %d\n", error);
+ return error;
+ }
+
+ error = input_register_device(in_dev);
+ if (error) {
+ dev_err(&client->dev,
+ "unable to register input device: %d\n", error);
+ return error;
+ }
+
+ i2c_set_clientdata(client, bu21029);
+
+ return 0;
+}
+
+static int __maybe_unused bu21029_suspend(struct device *dev)
+{
+ struct i2c_client *i2c = to_i2c_client(dev);
+ struct bu21029_ts_data *bu21029 = i2c_get_clientdata(i2c);
+
+ if (!device_may_wakeup(dev)) {
+ mutex_lock(&bu21029->in_dev->mutex);
+ if (bu21029->in_dev->users)
+ bu21029_stop_chip(bu21029->in_dev);
+ mutex_unlock(&bu21029->in_dev->mutex);
+ }
+
+ return 0;
+}
+
+static int __maybe_unused bu21029_resume(struct device *dev)
+{
+ struct i2c_client *i2c = to_i2c_client(dev);
+ struct bu21029_ts_data *bu21029 = i2c_get_clientdata(i2c);
+
+ if (!device_may_wakeup(dev)) {
+ mutex_lock(&bu21029->in_dev->mutex);
+ if (bu21029->in_dev->users)
+ bu21029_start_chip(bu21029->in_dev);
+ mutex_unlock(&bu21029->in_dev->mutex);
+ }
+
+ return 0;
+}
+static SIMPLE_DEV_PM_OPS(bu21029_pm_ops, bu21029_suspend, bu21029_resume);
+
+static const struct i2c_device_id bu21029_ids[] = {
+ { DRIVER_NAME, 0 },
+ { /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(i2c, bu21029_ids);
+
+#ifdef CONFIG_OF
+static const struct of_device_id bu21029_of_ids[] = {
+ { .compatible = "rohm,bu21029" },
+ { /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, bu21029_of_ids);
+#endif
+
+static struct i2c_driver bu21029_driver = {
+ .driver = {
+ .name = DRIVER_NAME,
+ .of_match_table = of_match_ptr(bu21029_of_ids),
+ .pm = &bu21029_pm_ops,
+ },
+ .id_table = bu21029_ids,
+ .probe = bu21029_probe,
+};
+module_i2c_driver(bu21029_driver);
+
+MODULE_AUTHOR("Zhu Yi <yi.zhu5@cn.bosch.com>");
+MODULE_DESCRIPTION("Rohm BU21029 touchscreen controller driver");
+MODULE_LICENSE("GPL v2");
projects / platform / kernel / linux-rpi.git / commitdiff