IIO: Ingenic JZ47xx: Add touchscreen mode.
authorArtur Rojek <contact@artur-rojek.eu>
Sun, 19 Jul 2020 20:53:07 +0000 (22:53 +0200)
committerJonathan Cameron <Jonathan.Cameron@huawei.com>
Mon, 20 Jul 2020 09:28:39 +0000 (10:28 +0100)
The SADC component in JZ47xx SoCs provides support for touchscreen
operations (pen position and pen down pressure) in single-ended and
differential modes.

The touchscreen component of SADC takes a significant time to stabilize
after first receiving the clock and a delay of 50ms has been empirically
proven to be a safe value before data sampling can begin.

Of the known hardware to use this controller, GCW Zero and Anbernic RG-350
utilize the touchscreen mode by having their joystick(s) attached to the
X/Y positive/negative input pins.

JZ4770 and later SoCs introduce a low-level command feature. With it, up
to 32 commands can be programmed, each one corresponding to a sampling
job. It allows to change the low-voltage reference, the high-voltage
reference, have them connected to VCC, GND, or one of the X-/X+ or Y-/Y+
pins.

This patch introduces support for 6 stream-capable channels:
- channel #0 samples X+/GND
- channel #1 samples Y+/GND
- channel #2 samples X-/GND
- channel #3 samples Y-/GND
- channel #4 samples X+/X-
- channel #5 samples Y+/Y-

Being able to sample X-/GND and Y-/GND is useful on some devices, where
one joystick is connected to the X+/Y+ pins, and a second joystick is
connected to the X-/Y- pins.

All the boards which probe this driver have the interrupt provided from
Device Tree, with no need to handle a case where the IRQ was not provided.

Co-developed-by: Paul Cercueil <paul@crapouillou.net>
Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Signed-off-by: Artur Rojek <contact@artur-rojek.eu>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
drivers/iio/adc/Kconfig
drivers/iio/adc/ingenic-adc.c

index 12bb8b7..c331413 100644 (file)
@@ -465,6 +465,7 @@ config INA2XX_ADC
 config INGENIC_ADC
        tristate "Ingenic JZ47xx SoCs ADC driver"
        depends on MIPS || COMPILE_TEST
+       select IIO_BUFFER
        help
          Say yes here to build support for the Ingenic JZ47xx SoCs ADC unit.
 
index 16fc097..c5b0176 100644 (file)
@@ -8,7 +8,9 @@
 
 #include <dt-bindings/iio/adc/ingenic,adc.h>
 #include <linux/clk.h>
+#include <linux/iio/buffer.h>
 #include <linux/iio/iio.h>
+#include <linux/interrupt.h>
 #include <linux/io.h>
 #include <linux/iopoll.h>
 #include <linux/kernel.h>
 #define JZ_ADC_REG_CFG                 0x04
 #define JZ_ADC_REG_CTRL                        0x08
 #define JZ_ADC_REG_STATUS              0x0c
+#define JZ_ADC_REG_ADSAME              0x10
+#define JZ_ADC_REG_ADWAIT              0x14
 #define JZ_ADC_REG_ADTCH               0x18
 #define JZ_ADC_REG_ADBDAT              0x1c
 #define JZ_ADC_REG_ADSDAT              0x20
+#define JZ_ADC_REG_ADCMD               0x24
 #define JZ_ADC_REG_ADCLK               0x28
 
 #define JZ_ADC_REG_ENABLE_PD           BIT(7)
 #define JZ_ADC_REG_CFG_AUX_MD          (BIT(0) | BIT(1))
 #define JZ_ADC_REG_CFG_BAT_MD          BIT(4)
+#define JZ_ADC_REG_CFG_SAMPLE_NUM(n)   ((n) << 10)
+#define JZ_ADC_REG_CFG_PULL_UP(n)      ((n) << 16)
+#define JZ_ADC_REG_CFG_CMD_SEL         BIT(22)
+#define JZ_ADC_REG_CFG_TOUCH_OPS_MASK  (BIT(31) | GENMASK(23, 10))
 #define JZ_ADC_REG_ADCLK_CLKDIV_LSB    0
 #define JZ4725B_ADC_REG_ADCLK_CLKDIV10US_LSB   16
 #define JZ4770_ADC_REG_ADCLK_CLKDIV10US_LSB    8
 #define JZ4770_ADC_REG_ADCLK_CLKDIVMS_LSB      16
 
+#define JZ_ADC_REG_ADCMD_YNADC         BIT(7)
+#define JZ_ADC_REG_ADCMD_YPADC         BIT(8)
+#define JZ_ADC_REG_ADCMD_XNADC         BIT(9)
+#define JZ_ADC_REG_ADCMD_XPADC         BIT(10)
+#define JZ_ADC_REG_ADCMD_VREFPYP       BIT(11)
+#define JZ_ADC_REG_ADCMD_VREFPXP       BIT(12)
+#define JZ_ADC_REG_ADCMD_VREFPXN       BIT(13)
+#define JZ_ADC_REG_ADCMD_VREFPAUX      BIT(14)
+#define JZ_ADC_REG_ADCMD_VREFPVDD33    BIT(15)
+#define JZ_ADC_REG_ADCMD_VREFNYN       BIT(16)
+#define JZ_ADC_REG_ADCMD_VREFNXP       BIT(17)
+#define JZ_ADC_REG_ADCMD_VREFNXN       BIT(18)
+#define JZ_ADC_REG_ADCMD_VREFAUX       BIT(19)
+#define JZ_ADC_REG_ADCMD_YNGRU         BIT(20)
+#define JZ_ADC_REG_ADCMD_XNGRU         BIT(21)
+#define JZ_ADC_REG_ADCMD_XPGRU         BIT(22)
+#define JZ_ADC_REG_ADCMD_YPSUP         BIT(23)
+#define JZ_ADC_REG_ADCMD_XNSUP         BIT(24)
+#define JZ_ADC_REG_ADCMD_XPSUP         BIT(25)
+
 #define JZ_ADC_AUX_VREF                                3300
 #define JZ_ADC_AUX_VREF_BITS                   12
 #define JZ_ADC_BATTERY_LOW_VREF                        2500
 #define JZ4770_ADC_BATTERY_VREF                        6600
 #define JZ4770_ADC_BATTERY_VREF_BITS           12
 
+#define JZ_ADC_IRQ_AUX                 BIT(0)
+#define JZ_ADC_IRQ_BATTERY             BIT(1)
+#define JZ_ADC_IRQ_TOUCH               BIT(2)
+#define JZ_ADC_IRQ_PEN_DOWN            BIT(3)
+#define JZ_ADC_IRQ_PEN_UP              BIT(4)
+#define JZ_ADC_IRQ_PEN_DOWN_SLEEP      BIT(5)
+#define JZ_ADC_IRQ_SLEEP               BIT(7)
+
 struct ingenic_adc;
 
 struct ingenic_adc_soc_data {
@@ -69,6 +106,61 @@ struct ingenic_adc {
        bool low_vref_mode;
 };
 
+static void ingenic_adc_set_adcmd(struct iio_dev *iio_dev, unsigned long mask)
+{
+       struct ingenic_adc *adc = iio_priv(iio_dev);
+
+       mutex_lock(&adc->lock);
+
+       /* Init ADCMD */
+       readl(adc->base + JZ_ADC_REG_ADCMD);
+
+       if (mask & 0x3) {
+               /* Second channel (INGENIC_ADC_TOUCH_YP): sample YP vs. GND */
+               writel(JZ_ADC_REG_ADCMD_XNGRU
+                      | JZ_ADC_REG_ADCMD_VREFNXN | JZ_ADC_REG_ADCMD_VREFPVDD33
+                      | JZ_ADC_REG_ADCMD_YPADC,
+                      adc->base + JZ_ADC_REG_ADCMD);
+
+               /* First channel (INGENIC_ADC_TOUCH_XP): sample XP vs. GND */
+               writel(JZ_ADC_REG_ADCMD_YNGRU
+                      | JZ_ADC_REG_ADCMD_VREFNYN | JZ_ADC_REG_ADCMD_VREFPVDD33
+                      | JZ_ADC_REG_ADCMD_XPADC,
+                      adc->base + JZ_ADC_REG_ADCMD);
+       }
+
+       if (mask & 0xc) {
+               /* Fourth channel (INGENIC_ADC_TOUCH_YN): sample YN vs. GND */
+               writel(JZ_ADC_REG_ADCMD_XNGRU
+                      | JZ_ADC_REG_ADCMD_VREFNXN | JZ_ADC_REG_ADCMD_VREFPVDD33
+                      | JZ_ADC_REG_ADCMD_YNADC,
+                      adc->base + JZ_ADC_REG_ADCMD);
+
+               /* Third channel (INGENIC_ADC_TOUCH_XN): sample XN vs. GND */
+               writel(JZ_ADC_REG_ADCMD_YNGRU
+                      | JZ_ADC_REG_ADCMD_VREFNYN | JZ_ADC_REG_ADCMD_VREFPVDD33
+                      | JZ_ADC_REG_ADCMD_XNADC,
+                      adc->base + JZ_ADC_REG_ADCMD);
+       }
+
+       if (mask & 0x30) {
+               /* Sixth channel (INGENIC_ADC_TOUCH_YD): sample YP vs. YN */
+               writel(JZ_ADC_REG_ADCMD_VREFNYN | JZ_ADC_REG_ADCMD_VREFPVDD33
+                      | JZ_ADC_REG_ADCMD_YPADC,
+                      adc->base + JZ_ADC_REG_ADCMD);
+
+               /* Fifth channel (INGENIC_ADC_TOUCH_XD): sample XP vs. XN */
+               writel(JZ_ADC_REG_ADCMD_VREFNXN | JZ_ADC_REG_ADCMD_VREFPVDD33
+                      | JZ_ADC_REG_ADCMD_XPADC,
+                      adc->base + JZ_ADC_REG_ADCMD);
+       }
+
+       /* We're done */
+       writel(0, adc->base + JZ_ADC_REG_ADCMD);
+
+       mutex_unlock(&adc->lock);
+}
+
 static void ingenic_adc_set_config(struct ingenic_adc *adc,
                                   uint32_t mask,
                                   uint32_t val)
@@ -289,6 +381,72 @@ static const struct iio_chan_spec jz4740_channels[] = {
 
 static const struct iio_chan_spec jz4770_channels[] = {
        {
+               .type = IIO_VOLTAGE,
+               .indexed = 1,
+               .channel = INGENIC_ADC_TOUCH_XP,
+               .scan_index = 0,
+               .scan_type = {
+                       .sign = 'u',
+                       .realbits = 12,
+                       .storagebits = 16,
+               },
+       },
+       {
+               .type = IIO_VOLTAGE,
+               .indexed = 1,
+               .channel = INGENIC_ADC_TOUCH_YP,
+               .scan_index = 1,
+               .scan_type = {
+                       .sign = 'u',
+                       .realbits = 12,
+                       .storagebits = 16,
+               },
+       },
+       {
+               .type = IIO_VOLTAGE,
+               .indexed = 1,
+               .channel = INGENIC_ADC_TOUCH_XN,
+               .scan_index = 2,
+               .scan_type = {
+                       .sign = 'u',
+                       .realbits = 12,
+                       .storagebits = 16,
+               },
+       },
+       {
+               .type = IIO_VOLTAGE,
+               .indexed = 1,
+               .channel = INGENIC_ADC_TOUCH_YN,
+               .scan_index = 3,
+               .scan_type = {
+                       .sign = 'u',
+                       .realbits = 12,
+                       .storagebits = 16,
+               },
+       },
+       {
+               .type = IIO_VOLTAGE,
+               .indexed = 1,
+               .channel = INGENIC_ADC_TOUCH_XD,
+               .scan_index = 4,
+               .scan_type = {
+                       .sign = 'u',
+                       .realbits = 12,
+                       .storagebits = 16,
+               },
+       },
+       {
+               .type = IIO_VOLTAGE,
+               .indexed = 1,
+               .channel = INGENIC_ADC_TOUCH_YD,
+               .scan_index = 5,
+               .scan_type = {
+                       .sign = 'u',
+                       .realbits = 12,
+                       .storagebits = 16,
+               },
+       },
+       {
                .extend_name = "aux",
                .type = IIO_VOLTAGE,
                .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
@@ -491,13 +649,89 @@ static const struct iio_info ingenic_adc_info = {
        .of_xlate = ingenic_adc_of_xlate,
 };
 
+static int ingenic_adc_buffer_enable(struct iio_dev *iio_dev)
+{
+       struct ingenic_adc *adc = iio_priv(iio_dev);
+       int ret;
+
+       ret = clk_enable(adc->clk);
+       if (ret) {
+               dev_err(iio_dev->dev.parent, "Failed to enable clock: %d\n",
+                       ret);
+               return ret;
+       }
+
+       /* It takes significant time for the touchscreen hw to stabilize. */
+       msleep(50);
+       ingenic_adc_set_config(adc, JZ_ADC_REG_CFG_TOUCH_OPS_MASK,
+                              JZ_ADC_REG_CFG_SAMPLE_NUM(4) |
+                              JZ_ADC_REG_CFG_PULL_UP(4));
+
+       writew(80, adc->base + JZ_ADC_REG_ADWAIT);
+       writew(2, adc->base + JZ_ADC_REG_ADSAME);
+       writeb((u8)~JZ_ADC_IRQ_TOUCH, adc->base + JZ_ADC_REG_CTRL);
+       writel(0, adc->base + JZ_ADC_REG_ADTCH);
+
+       ingenic_adc_set_config(adc, JZ_ADC_REG_CFG_CMD_SEL,
+                              JZ_ADC_REG_CFG_CMD_SEL);
+       ingenic_adc_set_adcmd(iio_dev, iio_dev->active_scan_mask[0]);
+
+       ingenic_adc_enable(adc, 2, true);
+
+       return 0;
+}
+
+static int ingenic_adc_buffer_disable(struct iio_dev *iio_dev)
+{
+       struct ingenic_adc *adc = iio_priv(iio_dev);
+
+       ingenic_adc_enable(adc, 2, false);
+
+       ingenic_adc_set_config(adc, JZ_ADC_REG_CFG_CMD_SEL, 0);
+
+       writeb(0xff, adc->base + JZ_ADC_REG_CTRL);
+       writeb(0xff, adc->base + JZ_ADC_REG_STATUS);
+       ingenic_adc_set_config(adc, JZ_ADC_REG_CFG_TOUCH_OPS_MASK, 0);
+       writew(0, adc->base + JZ_ADC_REG_ADSAME);
+       writew(0, adc->base + JZ_ADC_REG_ADWAIT);
+       clk_disable(adc->clk);
+
+       return 0;
+}
+
+static const struct iio_buffer_setup_ops ingenic_buffer_setup_ops = {
+       .postenable = &ingenic_adc_buffer_enable,
+       .predisable = &ingenic_adc_buffer_disable
+};
+
+static irqreturn_t ingenic_adc_irq(int irq, void *data)
+{
+       struct iio_dev *iio_dev = data;
+       struct ingenic_adc *adc = iio_priv(iio_dev);
+       unsigned long mask = iio_dev->active_scan_mask[0];
+       unsigned int i;
+       u32 tdat[3];
+
+       for (i = 0; i < ARRAY_SIZE(tdat); mask >>= 2, i++) {
+               if (mask & 0x3)
+                       tdat[i] = readl(adc->base + JZ_ADC_REG_ADTCH);
+               else
+                       tdat[i] = 0;
+       }
+
+       iio_push_to_buffers(iio_dev, tdat);
+       writeb(JZ_ADC_IRQ_TOUCH, adc->base + JZ_ADC_REG_STATUS);
+
+       return IRQ_HANDLED;
+}
+
 static int ingenic_adc_probe(struct platform_device *pdev)
 {
        struct device *dev = &pdev->dev;
        struct iio_dev *iio_dev;
        struct ingenic_adc *adc;
        const struct ingenic_adc_soc_data *soc_data;
-       int ret;
+       int irq, ret;
 
        soc_data = device_get_match_data(dev);
        if (!soc_data)
@@ -512,6 +746,17 @@ static int ingenic_adc_probe(struct platform_device *pdev)
        mutex_init(&adc->aux_lock);
        adc->soc_data = soc_data;
 
+       irq = platform_get_irq(pdev, 0);
+       if (irq < 0)
+               return irq;
+
+       ret = devm_request_irq(dev, irq, ingenic_adc_irq, 0,
+                              dev_name(dev), iio_dev);
+       if (ret < 0) {
+               dev_err(dev, "Failed to request irq: %d\n", ret);
+               return ret;
+       }
+
        adc->base = devm_platform_ioremap_resource(pdev, 0);
        if (IS_ERR(adc->base))
                return PTR_ERR(adc->base);
@@ -551,7 +796,8 @@ static int ingenic_adc_probe(struct platform_device *pdev)
 
        iio_dev->dev.parent = dev;
        iio_dev->name = "jz-adc";
-       iio_dev->modes = INDIO_DIRECT_MODE;
+       iio_dev->modes = INDIO_DIRECT_MODE | INDIO_BUFFER_SOFTWARE;
+       iio_dev->setup_ops = &ingenic_buffer_setup_ops;
        iio_dev->channels = soc_data->channels;
        iio_dev->num_channels = soc_data->num_channels;
        iio_dev->info = &ingenic_adc_info;