Input: add support for the Samsung S6SY761 touchscreen

The S6SY761 touchscreen is a capicitive multi-touch controller
for mobile use. It's connected with i2c at the address 0x48.

This commit provides a basic version of the driver which can
handle only initialization, touch events and power states.

The controller is controlled by a firmware which, in the version
I currently have, doesn't provide all the possible
functionalities mentioned in the datasheet.
Signed-off-by: NAndi Shyti <andi.shyti@samsung.com>
Acked-by: NRob Herring <robh@kernel.org>
Signed-off-by: NDmitry Torokhov <dmitry.torokhov@gmail.com>

Documentation/devicetree/bindings/input/touchscreen/samsung,s6sy761.txt

+* Samsung S6SY761 touchscreen controller
+
+Required properties:
+- compatible		: must be "samsung,s6sy761"
+- reg			: I2C slave address, (e.g. 0x48)
+- interrupt-parent	: the phandle to the interrupt controller which provides
+			  the interrupt
+- interrupts		: interrupt specification
+- avdd-supply		: analogic power supply
+- vdd-supply		: power supply
+
+Optional properties:
+- touchscreen-size-x	: see touchscreen.txt. This property is embedded in the
+			  device. If defined it forces a different x resolution.
+- touchscreen-size-y	: see touchscreen.txt. This property is embedded in the
+			  device. If defined it forces a different y resolution.
+
+Example:
+
+i2c@00000000 {
+
+	/* ... */
+
+	touchscreen@48 {
+		compatible = "samsung,s6sy761";
+		reg = <0x48>;
+		interrupt-parent = <&gpa1>;
+		interrupts = <1 IRQ_TYPE_NONE>;
+		avdd-supply = <&ldo30_reg>;
+		vdd-supply = <&ldo31_reg>;
+		touchscreen-size-x = <4096>;
+		touchscreen-size-y = <4096>;
+	};
+};

drivers/input/touchscreen/Kconfig

@@ -404,6 +404,17 @@ config TOUCHSCREEN_S3C2410
 	  To compile this driver as a module, choose M here: the
 	  module will be called s3c2410_ts.
 
+config TOUCHSCREEN_S6SY761
+	tristate "Samsung S6SY761 Touchscreen driver"
+	depends on I2C
+	help
+	  Say Y if you have the Samsung S6SY761 driver
+
+	  If unsure, say N
+
+	  To compile this driver as module, choose M here: the
+	  module will be called s6sy761.
+
 config TOUCHSCREEN_GUNZE
 	tristate "Gunze AHL-51S touchscreen"
 	select SERIO

drivers/input/touchscreen/Makefile

@@ -67,6 +67,7 @@ obj-$(CONFIG_TOUCHSCREEN_PENMOUNT)	+= penmount.o
 obj-$(CONFIG_TOUCHSCREEN_PIXCIR)	+= pixcir_i2c_ts.o
 obj-$(CONFIG_TOUCHSCREEN_RM_TS)		+= raydium_i2c_ts.o
 obj-$(CONFIG_TOUCHSCREEN_S3C2410)	+= s3c2410_ts.o
+obj-$(CONFIG_TOUCHSCREEN_S6SY761)	+= s6sy761.o
 obj-$(CONFIG_TOUCHSCREEN_SILEAD)	+= silead.o
 obj-$(CONFIG_TOUCHSCREEN_SIS_I2C)	+= sis_i2c.o
 obj-$(CONFIG_TOUCHSCREEN_ST1232)	+= st1232.o

drivers/input/touchscreen/s6sy761.c

+/*
+ * Copyright (c) 2017 Samsung Electronics Co., Ltd.
+ * Author: Andi Shyti <andi.shyti@samsung.com>
+ *
+ * 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.
+ *
+ * Samsung S6SY761 Touchscreen device driver
+ */
+
+#include <asm/unaligned.h>
+#include <linux/delay.h>
+#include <linux/i2c.h>
+#include <linux/input/mt.h>
+#include <linux/input/touchscreen.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/module.h>
+#include <linux/pm_runtime.h>
+#include <linux/regulator/consumer.h>
+
+/* commands */
+#define S6SY761_SENSE_ON		0x10
+#define S6SY761_SENSE_OFF		0x11
+#define S6SY761_TOUCH_FUNCTION		0x30 /* R/W for get/set */
+#define S6SY761_FIRMWARE_INTEGRITY	0x21
+#define S6SY761_PANEL_INFO		0x23
+#define S6SY761_DEVICE_ID		0x52
+#define S6SY761_BOOT_STATUS		0x55
+#define S6SY761_READ_ONE_EVENT		0x60
+#define S6SY761_READ_ALL_EVENT		0x61
+#define S6SY761_CLEAR_EVENT_STACK	0x62
+#define S6SY761_APPLICATION_MODE	0xe4
+
+/* events */
+#define S6SY761_EVENT_INFO		0x02
+#define S6SY761_EVENT_VENDOR_INFO	0x07
+
+/* info */
+#define S6SY761_INFO_BOOT_COMPLETE	0x00
+
+/* firmware status */
+#define S6SY761_FW_OK			0x80
+
+/*
+ * the functionalities are put as a reference
+ * as in the device I am using none of them
+ * works therefore not used in this driver yet.
+ */
+/* touchscreen functionalities */
+#define S6SY761_MASK_TOUCH		BIT(0)
+#define S6SY761_MASK_HOVER		BIT(1)
+#define S6SY761_MASK_COVER		BIT(2)
+#define S6SY761_MASK_GLOVE		BIT(3)
+#define S6SY761_MASK_STYLUS		BIT(4)
+#define S6SY761_MASK_PALM		BIT(5)
+#define S6SY761_MASK_WET		BIT(6)
+#define S6SY761_MASK_PROXIMITY		BIT(7)
+
+/* boot status (BS) */
+#define S6SY761_BS_BOOT_LOADER		0x10
+#define S6SY761_BS_APPLICATION		0x20
+
+/* event id */
+#define S6SY761_EVENT_ID_COORDINATE	0x00
+#define S6SY761_EVENT_ID_STATUS		0x01
+
+/* event register masks */
+#define S6SY761_MASK_TOUCH_STATE	0xc0 /* byte 0 */
+#define S6SY761_MASK_TID		0x3c
+#define S6SY761_MASK_EID		0x03
+#define S6SY761_MASK_X			0xf0 /* byte 3 */
+#define S6SY761_MASK_Y			0x0f
+#define S6SY761_MASK_Z			0x3f /* byte 6 */
+#define S6SY761_MASK_LEFT_EVENTS	0x3f /* byte 7 */
+#define S6SY761_MASK_TOUCH_TYPE		0xc0 /* MSB in byte 6, LSB in byte 7 */
+
+/* event touch state values */
+#define S6SY761_TS_NONE			0x00
+#define S6SY761_TS_PRESS		0x01
+#define S6SY761_TS_MOVE			0x02
+#define S6SY761_TS_RELEASE		0x03
+
+/* application modes */
+#define S6SY761_APP_NORMAL		0x0
+#define S6SY761_APP_LOW_POWER		0x1
+#define S6SY761_APP_TEST		0x2
+#define S6SY761_APP_FLASH		0x3
+#define S6SY761_APP_SLEEP		0x4
+
+#define S6SY761_EVENT_SIZE		8
+#define S6SY761_EVENT_COUNT		32
+#define S6SY761_DEVID_SIZE		3
+#define S6SY761_PANEL_ID_SIZE		11
+#define S6SY761_TS_STATUS_SIZE		5
+#define S6SY761_MAX_FINGERS		10
+
+#define S6SY761_DEV_NAME	"s6sy761"
+
+enum s6sy761_regulators {
+	S6SY761_REGULATOR_VDD,
+	S6SY761_REGULATOR_AVDD,
+};
+
+struct s6sy761_data {
+	struct i2c_client *client;
+	struct regulator_bulk_data regulators[2];
+	struct input_dev *input;
+	struct touchscreen_properties prop;
+
+	u8 data[S6SY761_EVENT_SIZE * S6SY761_EVENT_COUNT];
+
+	u16 devid;
+	u8 tx_channel;
+};
+
+/*
+ * We can't simply use i2c_smbus_read_i2c_block_data because we
+ * need to read more than 255 bytes
+ */
+static int s6sy761_read_events(struct s6sy761_data *sdata, u16 n_events)
+{
+	u8 cmd = S6SY761_READ_ALL_EVENT;
+	struct i2c_msg msgs[2] = {
+		{
+			.addr	= sdata->client->addr,
+			.len	= 1,
+			.buf	= &cmd,
+		},
+		{
+			.addr	= sdata->client->addr,
+			.flags	= I2C_M_RD,
+			.len	= (n_events * S6SY761_EVENT_SIZE),
+			.buf	= sdata->data + S6SY761_EVENT_SIZE,
+		},
+	};
+	int ret;
+
+	ret = i2c_transfer(sdata->client->adapter, msgs, ARRAY_SIZE(msgs));
+	if (ret < 0)
+		return ret;
+
+	return ret == ARRAY_SIZE(msgs) ? 0 : -EIO;
+}
+
+static void s6sy761_report_coordinates(struct s6sy761_data *sdata,
+				       u8 *event, u8 tid)
+{
+	u8 major = event[4];
+	u8 minor = event[5];
+	u8 z = event[6] & S6SY761_MASK_Z;
+	u16 x = (event[1] << 3) | ((event[3] & S6SY761_MASK_X) >> 4);
+	u16 y = (event[2] << 3) | (event[3] & S6SY761_MASK_Y);
+
+	input_mt_slot(sdata->input, tid);
+
+	input_mt_report_slot_state(sdata->input, MT_TOOL_FINGER, true);
+	input_report_abs(sdata->input, ABS_MT_POSITION_X, x);
+	input_report_abs(sdata->input, ABS_MT_POSITION_Y, y);
+	input_report_abs(sdata->input, ABS_MT_TOUCH_MAJOR, major);
+	input_report_abs(sdata->input, ABS_MT_TOUCH_MINOR, minor);
+	input_report_abs(sdata->input, ABS_MT_PRESSURE, z);
+
+	input_sync(sdata->input);
+}
+
+static void s6sy761_report_release(struct s6sy761_data *sdata,
+				   u8 *event, u8 tid)
+{
+	input_mt_slot(sdata->input, tid);
+	input_mt_report_slot_state(sdata->input, MT_TOOL_FINGER, false);
+
+	input_sync(sdata->input);
+}
+
+static void s6sy761_handle_coordinates(struct s6sy761_data *sdata, u8 *event)
+{
+	u8 tid;
+	u8 touch_state;
+
+	if (unlikely(!(event[0] & S6SY761_MASK_TID)))
+		return;
+
+	tid = ((event[0] & S6SY761_MASK_TID) >> 2) - 1;
+	touch_state = (event[0] & S6SY761_MASK_TOUCH_STATE) >> 6;
+
+	switch (touch_state) {
+
+	case S6SY761_TS_NONE:
+		break;
+	case S6SY761_TS_RELEASE:
+		s6sy761_report_release(sdata, event, tid);
+		break;
+	case S6SY761_TS_PRESS:
+	case S6SY761_TS_MOVE:
+		s6sy761_report_coordinates(sdata, event, tid);
+		break;
+	}
+}
+
+static void s6sy761_handle_events(struct s6sy761_data *sdata, u8 n_events)
+{
+	int i;
+
+	for (i = 0; i < n_events; i++) {
+		u8 *event = &sdata->data[i * S6SY761_EVENT_SIZE];
+		u8 event_id = event[0] & S6SY761_MASK_EID;
+
+		if (!event[0])
+			return;
+
+		switch (event_id) {
+
+		case S6SY761_EVENT_ID_COORDINATE:
+			s6sy761_handle_coordinates(sdata, event);
+			break;
+
+		case S6SY761_EVENT_ID_STATUS:
+			break;
+
+		default:
+			break;
+		}
+	}
+}
+
+static irqreturn_t s6sy761_irq_handler(int irq, void *dev)
+{
+	struct s6sy761_data *sdata = dev;
+	int ret;
+	u8 n_events;
+
+	ret = i2c_smbus_read_i2c_block_data(sdata->client,
+					    S6SY761_READ_ONE_EVENT,
+					    S6SY761_EVENT_SIZE,
+					    sdata->data);
+	if (ret < 0) {
+		dev_err(&sdata->client->dev, "failed to read events\n");
+		return IRQ_HANDLED;
+	}
+
+	if (!sdata->data[0])
+		return IRQ_HANDLED;
+
+	n_events = sdata->data[7] & S6SY761_MASK_LEFT_EVENTS;
+	if (unlikely(n_events > S6SY761_EVENT_COUNT - 1))
+		return IRQ_HANDLED;
+
+	if (n_events) {
+		ret = s6sy761_read_events(sdata, n_events);
+		if (ret < 0) {
+			dev_err(&sdata->client->dev, "failed to read events\n");
+			return IRQ_HANDLED;
+		}
+	}
+
+	s6sy761_handle_events(sdata, n_events +  1);
+
+	return IRQ_HANDLED;
+}
+
+static int s6sy761_input_open(struct input_dev *dev)
+{
+	struct s6sy761_data *sdata = input_get_drvdata(dev);
+
+	return i2c_smbus_write_byte(sdata->client, S6SY761_SENSE_ON);
+}
+
+static void s6sy761_input_close(struct input_dev *dev)
+{
+	struct s6sy761_data *sdata = input_get_drvdata(dev);
+	int ret;
+
+	ret = i2c_smbus_write_byte(sdata->client, S6SY761_SENSE_OFF);
+	if (ret)
+		dev_err(&sdata->client->dev, "failed to turn off sensing\n");
+}
+
+static ssize_t s6sy761_sysfs_devid(struct device *dev,
+				struct device_attribute *attr, char *buf)
+{
+	struct s6sy761_data *sdata = dev_get_drvdata(dev);
+
+	return sprintf(buf, "%#x\n", sdata->devid);
+}
+
+static DEVICE_ATTR(devid, 0444, s6sy761_sysfs_devid, NULL);
+
+static struct attribute *s6sy761_sysfs_attrs[] = {
+	&dev_attr_devid.attr,
+	NULL
+};
+
+static struct attribute_group s6sy761_attribute_group = {
+	.attrs = s6sy761_sysfs_attrs
+};
+
+static int s6sy761_power_on(struct s6sy761_data *sdata)
+{
+	u8 buffer[S6SY761_EVENT_SIZE];
+	u8 event;
+	int ret;
+
+	ret = regulator_bulk_enable(ARRAY_SIZE(sdata->regulators),
+				    sdata->regulators);
+	if (ret)
+		return ret;
+
+	msleep(140);
+
+	/* double check whether the touch is functional */
+	ret = i2c_smbus_read_i2c_block_data(sdata->client,
+					    S6SY761_READ_ONE_EVENT,
+					    S6SY761_EVENT_SIZE,
+					    buffer);
+	if (ret < 0)
+		return ret;
+
+	event = (buffer[0] >> 2) & 0xf;
+
+	if ((event != S6SY761_EVENT_INFO &&
+	     event != S6SY761_EVENT_VENDOR_INFO) ||
+	    buffer[1] != S6SY761_INFO_BOOT_COMPLETE) {
+		return -ENODEV;
+	}
+
+	ret = i2c_smbus_read_byte_data(sdata->client, S6SY761_BOOT_STATUS);
+	if (ret < 0)
+		return ret;
+
+	/* for some reasons the device might be stuck in the bootloader */
+	if (ret != S6SY761_BS_APPLICATION)
+		return -ENODEV;
+
+	/* enable touch functionality */
+	ret = i2c_smbus_write_word_data(sdata->client,
+					S6SY761_TOUCH_FUNCTION,
+					S6SY761_MASK_TOUCH);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+static int s6sy761_hw_init(struct s6sy761_data *sdata,
+			   unsigned int *max_x, unsigned int *max_y)
+{
+	u8 buffer[S6SY761_PANEL_ID_SIZE]; /* larger read size */
+	int ret;
+
+	ret = s6sy761_power_on(sdata);
+	if (ret)
+		return ret;
+
+	ret = i2c_smbus_read_i2c_block_data(sdata->client,
+					    S6SY761_DEVICE_ID,
+					    S6SY761_DEVID_SIZE,
+					    buffer);
+	if (ret < 0)
+		return ret;
+
+	sdata->devid = get_unaligned_be16(buffer + 1);
+
+	ret = i2c_smbus_read_i2c_block_data(sdata->client,
+					    S6SY761_PANEL_INFO,
+					    S6SY761_PANEL_ID_SIZE,
+					    buffer);
+	if (ret < 0)
+		return ret;
+
+	*max_x = get_unaligned_be16(buffer);
+	*max_y = get_unaligned_be16(buffer + 2);
+
+	/* if no tx channels defined, at least keep one */
+	sdata->tx_channel = max_t(u8, buffer[8], 1);
+
+	ret = i2c_smbus_read_byte_data(sdata->client,
+				       S6SY761_FIRMWARE_INTEGRITY);
+	if (ret < 0)
+		return ret;
+	else if (ret != S6SY761_FW_OK)
+		return -ENODEV;
+
+	return 0;
+}
+
+static void s6sy761_power_off(void *data)
+{
+	struct s6sy761_data *sdata = data;
+
+	disable_irq(sdata->client->irq);
+	regulator_bulk_disable(ARRAY_SIZE(sdata->regulators),
+						sdata->regulators);
+}
+
+static int s6sy761_probe(struct i2c_client *client,
+			 const struct i2c_device_id *id)
+{
+	struct s6sy761_data *sdata;
+	unsigned int max_x, max_y;
+	int err;
+
+	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C |
+						I2C_FUNC_SMBUS_BYTE_DATA |
+						I2C_FUNC_SMBUS_I2C_BLOCK))
+		return -ENODEV;
+
+	sdata = devm_kzalloc(&client->dev, sizeof(*sdata), GFP_KERNEL);
+	if (!sdata)
+		return -ENOMEM;
+
+	i2c_set_clientdata(client, sdata);
+	sdata->client = client;
+
+	sdata->regulators[S6SY761_REGULATOR_VDD].supply = "vdd";
+	sdata->regulators[S6SY761_REGULATOR_AVDD].supply = "avdd";
+	err = devm_regulator_bulk_get(&client->dev,
+				      ARRAY_SIZE(sdata->regulators),
+				      sdata->regulators);
+	if (err)
+		return err;
+
+	err = devm_add_action_or_reset(&client->dev, s6sy761_power_off, sdata);
+	if (err)
+		return err;
+
+	err = s6sy761_hw_init(sdata, &max_x, &max_y);
+	if (err)
+		return err;
+
+	sdata->input = devm_input_allocate_device(&client->dev);
+	if (!sdata->input)
+		return -ENOMEM;
+
+	sdata->input->name = S6SY761_DEV_NAME;
+	sdata->input->id.bustype = BUS_I2C;
+	sdata->input->open = s6sy761_input_open;
+	sdata->input->close = s6sy761_input_close;
+
+	input_set_abs_params(sdata->input, ABS_MT_POSITION_X, 0, max_x, 0, 0);
+	input_set_abs_params(sdata->input, ABS_MT_POSITION_Y, 0, max_y, 0, 0);
+	input_set_abs_params(sdata->input, ABS_MT_TOUCH_MAJOR, 0, 255, 0, 0);
+	input_set_abs_params(sdata->input, ABS_MT_TOUCH_MINOR, 0, 255, 0, 0);
+	input_set_abs_params(sdata->input, ABS_MT_TOUCH_MAJOR, 0, 255, 0, 0);
+	input_set_abs_params(sdata->input, ABS_MT_TOUCH_MINOR, 0, 255, 0, 0);
+	input_set_abs_params(sdata->input, ABS_MT_PRESSURE, 0, 255, 0, 0);
+
+	touchscreen_parse_properties(sdata->input, true, &sdata->prop);
+
+	if (!input_abs_get_max(sdata->input, ABS_X) ||
+	    !input_abs_get_max(sdata->input, ABS_Y)) {
+		dev_warn(&client->dev, "the axis have not been set\n");
+	}
+
+	err = input_mt_init_slots(sdata->input, sdata->tx_channel,
+				  INPUT_MT_DIRECT);
+	if (err)
+		return err;
+
+	input_set_drvdata(sdata->input, sdata);
+
+	err = input_register_device(sdata->input);
+	if (err)
+		return err;
+
+	err = devm_request_threaded_irq(&client->dev, client->irq, NULL,
+					s6sy761_irq_handler,
+					IRQF_TRIGGER_LOW | IRQF_ONESHOT,
+					"s6sy761_irq", sdata);
+	if (err)
+		return err;
+
+	err = devm_device_add_group(&client->dev, &s6sy761_attribute_group);
+	if (err)
+		return err;
+
+	pm_runtime_enable(&client->dev);
+
+	return 0;
+}
+
+static int s6sy761_remove(struct i2c_client *client)
+{
+	pm_runtime_disable(&client->dev);
+
+	return 0;
+}
+
+static int __maybe_unused s6sy761_runtime_suspend(struct device *dev)
+{
+	struct s6sy761_data *sdata = dev_get_drvdata(dev);
+
+	return i2c_smbus_write_byte_data(sdata->client,
+				S6SY761_APPLICATION_MODE, S6SY761_APP_SLEEP);
+}
+
+static int __maybe_unused s6sy761_runtime_resume(struct device *dev)
+{
+	struct s6sy761_data *sdata = dev_get_drvdata(dev);
+
+	return i2c_smbus_write_byte_data(sdata->client,
+				S6SY761_APPLICATION_MODE, S6SY761_APP_NORMAL);
+}
+
+static int __maybe_unused s6sy761_suspend(struct device *dev)
+{
+	struct s6sy761_data *sdata = dev_get_drvdata(dev);
+
+	s6sy761_power_off(sdata);
+
+	return 0;
+}
+
+static int __maybe_unused s6sy761_resume(struct device *dev)
+{
+	struct s6sy761_data *sdata = dev_get_drvdata(dev);
+
+	enable_irq(sdata->client->irq);
+
+	return s6sy761_power_on(sdata);
+}
+
+static const struct dev_pm_ops s6sy761_pm_ops = {
+	SET_SYSTEM_SLEEP_PM_OPS(s6sy761_suspend, s6sy761_resume)
+	SET_RUNTIME_PM_OPS(s6sy761_runtime_suspend,
+				s6sy761_runtime_resume, NULL)
+};
+
+#ifdef CONFIG_OF
+static const struct of_device_id s6sy761_of_match[] = {
+	{ .compatible = "samsung,s6sy761", },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, s6sy761_of_match);
+#endif
+
+static const struct i2c_device_id s6sy761_id[] = {
+	{ "s6sy761", 0 },
+	{ },
+};
+MODULE_DEVICE_TABLE(i2c, s6sy761_id);
+
+static struct i2c_driver s6sy761_driver = {
+	.driver = {
+		.name = S6SY761_DEV_NAME,
+		.of_match_table = of_match_ptr(s6sy761_of_match),
+		.pm = &s6sy761_pm_ops,
+	},
+	.probe = s6sy761_probe,
+	.remove = s6sy761_remove,
+	.id_table = s6sy761_id,
+};
+
+module_i2c_driver(s6sy761_driver);
+
+MODULE_AUTHOR("Andi Shyti <andi.shyti@samsung.com>");
+MODULE_DESCRIPTION("Samsung S6SY761 Touch Screen");
+MODULE_LICENSE("GPL v2");