Message-id: <20170327130743.27783-3-andi.shyti@samsung.com>
Date:   Mon, 27 Mar 2017 22:07:43 +0900
From:   Andi Shyti <andi.shyti@...sung.com>
To:     Dmitry Torokhov <dmitry.torokhov@...il.com>,
        Rob Herring <robh+dt@...nel.org>
Cc:     Javier Martinez Canillas <javier@....samsung.com>,
        Andrzej Hajda <a.hajda@...sung.com>,
        Chanwoo Choi <cw00.choi@...sung.com>,
        linux-input@...r.kernel.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, Andi Shyti <andi.shyti@...sung.com>,
        Andi Shyti <andi@...zian.org>
Subject: [PATCH v3 2/2] Input: add support for the STMicroelectronics FingerTip
 touchscreen

The stmfts (ST-Microelectronics FingerTip S) touchscreen device
is a capacitive multi-touch controller mainly for mobile use.

It's connected through i2c bus at the address 0x49 and it
interfaces with userspace through input event interface.

At the current state it provides a touchscreen multitouch
functionality up to 10 fingers. Each finger is enumerated with a
distinctive id (from 0 to 9).

If enabled the device can support single "touch" hovering, by
providing three coordinates, x, y and distance.

It is possible to select the touchkey functionality which
provides a basic two keys interface for "home" and "back" menu,
typical in mobile phones.

Signed-off-by: Andi Shyti <andi.shyti@...sung.com>
---
 drivers/input/touchscreen/Kconfig  |  12 +
 drivers/input/touchscreen/Makefile |   1 +
 drivers/input/touchscreen/stmfts.c | 805 +++++++++++++++++++++++++++++++++++++
 3 files changed, 818 insertions(+)
 create mode 100644 drivers/input/touchscreen/stmfts.c

diff --git a/drivers/input/touchscreen/Kconfig b/drivers/input/touchscreen/Kconfig
index 33c62e5de4fa..f8631c64290d 100644
--- a/drivers/input/touchscreen/Kconfig
+++ b/drivers/input/touchscreen/Kconfig
@@ -1114,6 +1114,18 @@ config TOUCHSCREEN_ST1232
 	  To compile this driver as a module, choose M here: the
 	  module will be called st1232_ts.
 
+config TOUCHSCREEN_STMFTS
+	tristate "STMicroelectronics STMFTS touchscreen"
+	depends on I2C
+	depends on INPUT
+	depends on LEDS_CLASS
+	help
+	  Say Y here if you want support for STMicroelectronics
+	  STMFTS touchscreen.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called stmfts.
+
 config TOUCHSCREEN_STMPE
 	tristate "STMicroelectronics STMPE touchscreens"
 	depends on MFD_STMPE
diff --git a/drivers/input/touchscreen/Makefile b/drivers/input/touchscreen/Makefile
index 18e476948e44..6badce87037b 100644
--- a/drivers/input/touchscreen/Makefile
+++ b/drivers/input/touchscreen/Makefile
@@ -67,6 +67,7 @@ obj-$(CONFIG_TOUCHSCREEN_S3C2410)	+= s3c2410_ts.o
 obj-$(CONFIG_TOUCHSCREEN_SILEAD)	+= silead.o
 obj-$(CONFIG_TOUCHSCREEN_SIS_I2C)	+= sis_i2c.o
 obj-$(CONFIG_TOUCHSCREEN_ST1232)	+= st1232.o
+obj-$(CONFIG_TOUCHSCREEN_STMFTS)	+= stmfts.o
 obj-$(CONFIG_TOUCHSCREEN_STMPE)		+= stmpe-ts.o
 obj-$(CONFIG_TOUCHSCREEN_SUN4I)		+= sun4i-ts.o
 obj-$(CONFIG_TOUCHSCREEN_SUR40)		+= sur40.o
diff --git a/drivers/input/touchscreen/stmfts.c b/drivers/input/touchscreen/stmfts.c
new file mode 100644
index 000000000000..2e18b1456f42
--- /dev/null
+++ b/drivers/input/touchscreen/stmfts.c
@@ -0,0 +1,805 @@
+/*
+ * Copyright (c) 2017 Samsung Electronics Co., Ltd.
+ * Author: Andi Shyti <andi.shyti@...sung.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.
+ *
+ * STMicroelectronics FTS Touchscreen device driver
+ */
+
+#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/leds.h>
+#include <linux/module.h>
+#include <linux/pm_runtime.h>
+#include <linux/regulator/consumer.h>
+
+/* I2C commands */
+#define STMFTS_READ_INFO			0x80
+#define STMFTS_READ_STATUS			0x84
+#define STMFTS_READ_ONE_EVENT			0x85
+#define STMFTS_READ_ALL_EVENT			0x86
+#define STMFTS_LATEST_EVENT			0x87
+#define STMFTS_SLEEP_IN				0x90
+#define STMFTS_SLEEP_OUT			0x91
+#define STMFTS_MS_MT_SENSE_OFF			0x92
+#define STMFTS_MS_MT_SENSE_ON			0x93
+#define STMFTS_SS_HOVER_SENSE_OFF		0x94
+#define STMFTS_SS_HOVER_SENSE_ON		0x95
+#define STMFTS_MS_KEY_SENSE_OFF			0x9a
+#define STMFTS_MS_KEY_SENSE_ON			0x9b
+#define STMFTS_SYSTEM_RESET			0xa0
+#define STMFTS_CLEAR_EVENT_STACK		0xa1
+#define STMFTS_FULL_FORCE_CALIBRATION		0xa2
+#define STMFTS_MS_CX_TUNING			0xa3
+#define STMFTS_SS_CX_TUNING			0xa4
+
+/* events */
+#define STMFTS_EV_NO_EVENT			0x00
+#define STMFTS_EV_MULTI_TOUCH_DETECTED		0x02
+#define STMFTS_EV_MULTI_TOUCH_ENTER		0x03
+#define STMFTS_EV_MULTI_TOUCH_LEAVE		0x04
+#define STMFTS_EV_MULTI_TOUCH_MOTION		0x05
+#define STMFTS_EV_HOVER_ENTER			0x07
+#define STMFTS_EV_HOVER_LEAVE			0x08
+#define STMFTS_EV_HOVER_MOTION			0x09
+#define STMFTS_EV_KEY_STATUS			0x0e
+#define STMFTS_EV_ERROR				0x0f
+#define STMFTS_EV_CONTROLLER_READY		0x10
+#define STMFTS_EV_SLEEP_OUT_CONTROLLER_READY	0x11
+#define STMFTS_EV_STATUS			0x16
+#define STMFTS_EV_DEBUG				0xdb
+
+/* multi touch related event masks */
+#define STMFTS_MASK_EVENT_ID			0x0f
+#define STMFTS_MASK_TOUCH_ID			0xf0
+#define STMFTS_MASK_LEFT_EVENT			0x0f
+#define STMFTS_MASK_X_MSB			0x0f
+#define STMFTS_MASK_Y_LSB			0xf0
+
+/* key related event masks */
+#define STMFTS_MASK_KEY_NO_TOUCH		0x00
+#define STMFTS_MASK_KEY_MENU			0x01
+#define STMFTS_MASK_KEY_BACK			0x02
+
+#define STMFTS_EVENT_SIZE	8
+#define STMFTS_STACK_DEPTH	32
+#define STMFTS_DATA_MAX_SIZE	(STMFTS_EVENT_SIZE * STMFTS_STACK_DEPTH)
+#define STMFTS_MAX_FINGERS	10
+#define STMFTS_DEV_NAME		"stmfts"
+
+enum stmfts_regulators {
+	STMFTS_REGULATOR_VDD,
+	STMFTS_REGULATOR_AVDD,
+};
+
+struct stmfts_data {
+	struct i2c_client *client;
+	struct input_dev *input;
+	struct led_classdev led_cdev;
+	struct mutex mutex;
+
+	struct touchscreen_properties prop;
+
+	struct regulator_bulk_data regulators[2];
+
+	/* ledvdd will be used also to check
+	 * whether the LED is supported
+	 */
+	struct regulator *ledvdd;
+
+	u16 chip_id;
+	u8 chip_ver;
+	u16 fw_ver;
+	u8 config_id;
+	u8 config_ver;
+
+	u8 data[STMFTS_DATA_MAX_SIZE];
+
+	struct completion signal;
+
+	bool use_key;
+	bool led_status;
+	bool hover_enabled;
+	bool running;
+};
+
+static int stmfts_read_i2c_block_data(struct stmfts_data *sdata)
+{
+	struct i2c_msg msgs[2];
+	u8 cmd = STMFTS_READ_ALL_EVENT;
+
+	msgs[0].addr = sdata->client->addr;
+	msgs[0].flags = 0;
+	msgs[0].len = 1;
+	msgs[0].buf = &cmd;
+
+	msgs[1].addr = sdata->client->addr;
+	msgs[1].flags = I2C_M_RD;
+	msgs[1].len = STMFTS_DATA_MAX_SIZE - STMFTS_EVENT_SIZE;
+	msgs[1].buf = sdata->data + STMFTS_EVENT_SIZE;
+
+	return i2c_transfer(sdata->client->adapter, msgs, ARRAY_SIZE(msgs));
+}
+
+static void stmfts_brightness_set(struct led_classdev *led_cdev,
+					enum led_brightness value)
+{
+	struct stmfts_data *sdata = container_of(led_cdev,
+					struct stmfts_data, led_cdev);
+
+	if (value == sdata->led_status || !sdata->ledvdd)
+		return;
+
+	if (!value) {
+		regulator_disable(sdata->ledvdd);
+	} else {
+		int err = regulator_enable(sdata->ledvdd);
+
+		if (err)
+			dev_warn(&sdata->client->dev,
+				"failed to disable ledvdd regulator\n");
+	}
+
+	sdata->led_status = value;
+}
+
+static enum led_brightness stmfts_brightness_get(struct led_classdev *led_cdev)
+{
+	struct stmfts_data *sdata = container_of(led_cdev,
+						struct stmfts_data, led_cdev);
+
+	return !!regulator_is_enabled(sdata->ledvdd);
+}
+
+static void stmfts_parse_event(struct stmfts_data *sdata)
+{
+	u8 id, t_id;
+	u16 x, y, z, maj, min, orientation, area;
+	u8 *event;
+	int i;
+
+	for (i = 0; i < STMFTS_STACK_DEPTH; i++) {
+		event = &sdata->data[i*STMFTS_EVENT_SIZE];
+
+		id = event[0] & STMFTS_MASK_EVENT_ID;
+		t_id = (event[0] & STMFTS_MASK_TOUCH_ID) >> 4;
+
+		switch (id) {
+		case STMFTS_EV_NO_EVENT:
+			return;
+
+		case STMFTS_EV_MULTI_TOUCH_ENTER:
+		case STMFTS_EV_MULTI_TOUCH_LEAVE:
+		case STMFTS_EV_MULTI_TOUCH_MOTION:
+			if (id == STMFTS_EV_MULTI_TOUCH_ENTER)
+				input_mt_report_slot_state(sdata->input,
+							MT_TOOL_FINGER, true);
+			else if (id == STMFTS_EV_MULTI_TOUCH_LEAVE)
+				input_mt_report_slot_state(sdata->input,
+							MT_TOOL_FINGER, false);
+
+			x = event[1] | ((event[2] & STMFTS_MASK_X_MSB) << 8);
+			y = (event[2] >> 4) | (event[3] << 4);
+
+			maj = event[4];
+			min = event[5];
+			orientation = event[6];
+			area = event[7];
+
+			input_mt_slot(sdata->input, t_id);
+			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, maj);
+			input_report_abs(sdata->input, ABS_MT_TOUCH_MINOR, min);
+			input_report_abs(sdata->input, ABS_MT_PRESSURE, area);
+			input_report_abs(sdata->input, ABS_MT_ORIENTATION,
+								orientation);
+			input_sync(sdata->input);
+
+			break;
+
+		case STMFTS_EV_HOVER_ENTER:
+		case STMFTS_EV_HOVER_LEAVE:
+		case STMFTS_EV_HOVER_MOTION:
+			x = (event[2] << 4) | (event[4] >> 4);
+			y = (event[3] << 4) | (event[4] & STMFTS_MASK_Y_LSB);
+			z = event[5];
+			orientation = event[6] & STMFTS_MASK_Y_LSB;
+
+			input_report_abs(sdata->input, ABS_X, x);
+			input_report_abs(sdata->input, ABS_Y, y);
+			input_report_abs(sdata->input, ABS_DISTANCE, z);
+			input_sync(sdata->input);
+
+			break;
+
+		case STMFTS_EV_KEY_STATUS:
+			switch (event[2]) {
+			case 0:
+				input_report_key(sdata->input, KEY_BACK, 0);
+				input_report_key(sdata->input, KEY_MENU, 0);
+				break;
+
+			case STMFTS_MASK_KEY_BACK:
+				input_report_key(sdata->input, KEY_BACK, 1);
+				break;
+
+			case STMFTS_MASK_KEY_MENU:
+				input_report_key(sdata->input, KEY_MENU, 1);
+				break;
+
+			default:
+				dev_warn(&sdata->client->dev,
+						"unknown key event\n");
+			}
+
+			input_sync(sdata->input);
+			break;
+
+		case STMFTS_EV_ERROR:
+			dev_warn(&sdata->client->dev,
+					"error code: 0x%x%x%x%x%x%x",
+					event[6], event[5], event[4],
+					event[3], event[2], event[1]);
+			break;
+
+		default:
+			dev_err(&sdata->client->dev,
+				"unknown event 0x%x\n", event[0]);
+		}
+	}
+}
+
+static irqreturn_t stmfts_irq_handler(int irq, void *dev)
+{
+	struct stmfts_data *sdata = dev;
+	int ret;
+
+	mutex_lock(&sdata->mutex);
+	ret = i2c_smbus_read_i2c_block_data(sdata->client,
+						STMFTS_READ_ONE_EVENT,
+						STMFTS_EVENT_SIZE, sdata->data);
+
+	if (ret < 0 || ret != STMFTS_EVENT_SIZE)
+		goto exit;
+
+	switch (sdata->data[0]) {
+	case STMFTS_EV_CONTROLLER_READY:
+	case STMFTS_EV_SLEEP_OUT_CONTROLLER_READY:
+	case STMFTS_EV_STATUS:
+		complete(&sdata->signal);
+	case STMFTS_EV_NO_EVENT:
+	case STMFTS_EV_DEBUG:
+		break;
+
+	default:
+		if (unlikely(!sdata->input))
+			goto exit;
+
+		ret = stmfts_read_i2c_block_data(sdata);
+		if (ret < 0)
+			goto exit;
+
+		stmfts_parse_event(sdata);
+	}
+
+exit:
+	mutex_unlock(&sdata->mutex);
+	return IRQ_HANDLED;
+}
+
+static int stmfts_write_and_wait(struct stmfts_data *sdata, const u8 cmd)
+{
+	int err;
+
+	err = i2c_smbus_write_byte(sdata->client, cmd);
+	if (err)
+		return err;
+
+	err = wait_for_completion_timeout(&sdata->signal,
+					msecs_to_jiffies(1000));
+
+	return !err ? -ETIMEDOUT : 0;
+}
+
+static int stmfts_input_open(struct input_dev *dev)
+{
+	int ret;
+	struct stmfts_data *sdata = input_get_drvdata(dev);
+
+	ret = pm_runtime_get_sync(&sdata->client->dev);
+	if (ret < 0)
+		return ret;
+
+	ret = i2c_smbus_write_byte(sdata->client, STMFTS_MS_MT_SENSE_ON);
+	if (ret)
+		return ret;
+
+	mutex_lock(&sdata->mutex);
+	sdata->running = true;
+
+	if (sdata->hover_enabled) {
+		ret = i2c_smbus_write_byte(sdata->client,
+						STMFTS_SS_HOVER_SENSE_ON);
+		if (ret)
+			dev_warn(&sdata->client->dev,
+						"failed to enable hover\n");
+	}
+	mutex_unlock(&sdata->mutex);
+
+	if (sdata->use_key) {
+		ret = i2c_smbus_write_byte(sdata->client,
+						STMFTS_MS_KEY_SENSE_ON);
+		if (ret)
+			/* I can still use only the touch screen */
+			dev_warn(&sdata->client->dev,
+						"failed to enable touchkey\n");
+	}
+
+	return 0;
+}
+
+static void stmfts_input_close(struct input_dev *dev)
+{
+	int ret;
+	struct stmfts_data *sdata = input_get_drvdata(dev);
+
+	ret = i2c_smbus_write_byte(sdata->client, STMFTS_MS_MT_SENSE_OFF);
+	if (ret)
+		dev_warn(&sdata->client->dev,
+					"failed to disable touchscreen\n");
+
+	mutex_lock(&sdata->mutex);
+	sdata->running = false;
+
+	if (sdata->hover_enabled) {
+		ret = i2c_smbus_write_byte(sdata->client,
+					STMFTS_SS_HOVER_SENSE_OFF);
+		if (ret)
+			dev_warn(&sdata->client->dev,
+						"failed to disable hover\n");
+	}
+	mutex_unlock(&sdata->mutex);
+
+	if (sdata->use_key) {
+		i2c_smbus_write_byte(sdata->client, STMFTS_MS_KEY_SENSE_OFF);
+		if (ret)
+			dev_warn(&sdata->client->dev,
+					"failed to disable touchkey\n");
+	}
+
+	pm_runtime_put_sync(&sdata->client->dev);
+}
+
+static ssize_t stmfts_sysfs_chip_id(struct device *dev,
+				struct device_attribute *attr, char *buf)
+{
+	struct stmfts_data *sdata = dev_get_drvdata(dev);
+
+	return sprintf(buf, "0x%x\n", sdata->chip_id);
+}
+
+static ssize_t stmfts_sysfs_chip_version(struct device *dev,
+				struct device_attribute *attr, char *buf)
+{
+	struct stmfts_data *sdata = dev_get_drvdata(dev);
+
+	return sprintf(buf, "%u\n", sdata->chip_ver);
+}
+
+static ssize_t stmfts_sysfs_fw_ver(struct device *dev,
+				struct device_attribute *attr, char *buf)
+{
+	struct stmfts_data *sdata = dev_get_drvdata(dev);
+
+	return sprintf(buf, "%u\n", sdata->fw_ver);
+}
+
+static ssize_t stmfts_sysfs_config_id(struct device *dev,
+				struct device_attribute *attr, char *buf)
+{
+	struct stmfts_data *sdata = dev_get_drvdata(dev);
+
+	return sprintf(buf, "0x%x\n", sdata->config_id);
+}
+
+static ssize_t stmfts_sysfs_config_version(struct device *dev,
+				struct device_attribute *attr, char *buf)
+{
+	struct stmfts_data *sdata = dev_get_drvdata(dev);
+
+	return sprintf(buf, "%u\n", sdata->config_ver);
+}
+
+static ssize_t stmfts_sysfs_read_status(struct device *dev,
+				struct device_attribute *attr, char *buf)
+{
+	struct stmfts_data *sdata = dev_get_drvdata(dev);
+	u8 status[4];
+	int ret;
+
+	ret = i2c_smbus_read_i2c_block_data(sdata->client,
+					STMFTS_READ_STATUS, 4, status);
+
+	return sprintf(buf, "0x%x\n", status[0]);
+}
+
+static ssize_t stmfts_sysfs_hover_enable_read(struct device *dev,
+				struct device_attribute *attr, char *buf)
+{
+	struct stmfts_data *sdata = dev_get_drvdata(dev);
+
+	return sprintf(buf, "%u\n", sdata->hover_enabled);
+}
+
+static ssize_t stmfts_sysfs_hover_enable_write(struct device *dev,
+				struct device_attribute *attr,
+				const char *buf, size_t len)
+{
+	unsigned long value;
+	int err;
+	struct stmfts_data *sdata = dev_get_drvdata(dev);
+
+	if (kstrtoul(buf, 0, &value))
+		return -EINVAL;
+
+	mutex_lock(&sdata->mutex);
+
+	if (value & sdata->hover_enabled)
+		goto out;
+
+	if (!sdata->running) {
+		sdata->hover_enabled = !!value;
+		goto out;
+	}
+
+	if (value) {
+		err = i2c_smbus_write_byte(sdata->client,
+						STMFTS_SS_HOVER_SENSE_ON);
+		sdata->hover_enabled = !err;
+	} else {
+		err = i2c_smbus_write_byte(sdata->client,
+					STMFTS_SS_HOVER_SENSE_OFF);
+		sdata->hover_enabled = !!err;
+	}
+
+	if (err)
+		dev_warn(&sdata->client->dev, "failed to %s hover\n",
+						value ? "enable" : "disable");
+out:
+	mutex_unlock(&sdata->mutex);
+
+	return len;
+}
+
+static DEVICE_ATTR(chip_id, 0444, stmfts_sysfs_chip_id, NULL);
+static DEVICE_ATTR(chip_version, 0444, stmfts_sysfs_chip_version, NULL);
+static DEVICE_ATTR(fw_ver, 0444, stmfts_sysfs_fw_ver, NULL);
+static DEVICE_ATTR(config_id, 0444, stmfts_sysfs_config_id, NULL);
+static DEVICE_ATTR(config_version, 0444, stmfts_sysfs_config_version, NULL);
+static DEVICE_ATTR(status, 0444, stmfts_sysfs_read_status, NULL);
+static DEVICE_ATTR(hover_enable, 0644, stmfts_sysfs_hover_enable_read,
+					stmfts_sysfs_hover_enable_write);
+
+static struct attribute *stmfts_sysfs_attrs[] = {
+	&dev_attr_chip_id.attr,
+	&dev_attr_chip_version.attr,
+	&dev_attr_fw_ver.attr,
+	&dev_attr_config_id.attr,
+	&dev_attr_config_version.attr,
+	&dev_attr_status.attr,
+	&dev_attr_hover_enable.attr,
+	NULL
+};
+
+static struct attribute_group stmfts_attribute_group = {
+	.attrs = stmfts_sysfs_attrs
+};
+
+static int stmfts_power_on(struct stmfts_data *sdata)
+{
+	int err;
+	u8 reg[8];
+
+	err = regulator_bulk_enable(ARRAY_SIZE(sdata->regulators),
+							sdata->regulators);
+	if (err)
+		return err;
+
+	/*
+	 * the datasheet does not specify the power on time, but considering
+	 * that the reset time is < 10ms, I sleep 20ms to be sure
+	 */
+	msleep(20);
+
+	err = i2c_smbus_read_i2c_block_data(sdata->client,
+					STMFTS_READ_INFO, 8, reg);
+	if (err < 0)
+		return err;
+	if (err != 8)
+		return -EIO;
+
+	sdata->chip_id = (reg[6] << 8) | reg[7];
+	sdata->chip_ver = reg[0];
+	sdata->fw_ver = (reg[2] << 8) | reg[3];
+	sdata->config_id = reg[4];
+	sdata->config_ver = reg[5];
+
+	reinit_completion(&sdata->signal);
+
+	enable_irq(sdata->client->irq);
+	err = stmfts_write_and_wait(sdata, STMFTS_SYSTEM_RESET);
+	if (err)
+		return err;
+
+	err = stmfts_write_and_wait(sdata, STMFTS_SLEEP_OUT);
+	if (err)
+		return err;
+
+	/* optional tuning */
+	err = stmfts_write_and_wait(sdata, STMFTS_MS_CX_TUNING);
+	if (err)
+		dev_warn(&sdata->client->dev, "failed to perform mutual auto tune\n");
+
+	/* optional tuning */
+	err = stmfts_write_and_wait(sdata, STMFTS_SS_CX_TUNING);
+	if (err)
+		dev_warn(&sdata->client->dev, "failed to perform self auto tune\n");
+
+	err = stmfts_write_and_wait(sdata, STMFTS_FULL_FORCE_CALIBRATION);
+	if (err)
+		return err;
+
+	/* at this point no one is using the touchscreen
+	 * and I don't really care about the return value
+	 */
+	i2c_smbus_write_byte(sdata->client, STMFTS_SLEEP_IN);
+
+	return 0;
+}
+
+static void stmfts_power_off(void *data)
+{
+	struct stmfts_data *sdata = data;
+
+	disable_irq(sdata->client->irq);
+	regulator_bulk_disable(ARRAY_SIZE(sdata->regulators),
+						sdata->regulators);
+}
+
+/* This function is void because I don't want to prevent using the touch key
+ * only because the LEDs don't get registered
+ */
+static int stmfts_enable_led(struct stmfts_data *sdata)
+{
+	int err;
+
+	/* get the regulator for powering the leds on */
+	sdata->ledvdd = devm_regulator_get(&sdata->client->dev, "ledvdd");
+	if (IS_ERR(sdata->ledvdd))
+		return PTR_ERR(sdata->ledvdd);
+
+	sdata->led_cdev.name = STMFTS_DEV_NAME;
+	sdata->led_cdev.max_brightness = LED_ON;
+	sdata->led_cdev.brightness = LED_OFF;
+	sdata->led_cdev.brightness_set = stmfts_brightness_set;
+	sdata->led_cdev.brightness_get = stmfts_brightness_get;
+
+	err = devm_led_classdev_register(&sdata->client->dev, &sdata->led_cdev);
+	if (err) {
+		devm_regulator_put(sdata->ledvdd);
+		return err;
+	}
+
+	return 0;
+}
+
+static int stmfts_probe(struct i2c_client *client,
+			const struct i2c_device_id *id)
+{
+	int err;
+	struct stmfts_data *sdata;
+
+	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C |
+						I2C_FUNC_SMBUS_BYTE_DATA |
+						I2C_FUNC_SMBUS_I2C_BLOCK))
+		return -ENODEV;
+
+	if (!client->dev.of_node)
+		return -ENOENT;
+
+	sdata = devm_kzalloc(&client->dev, sizeof(*sdata), GFP_KERNEL);
+	if (!sdata)
+		return -ENOMEM;
+
+	i2c_set_clientdata(client, sdata);
+
+	mutex_init(&sdata->mutex);
+
+	sdata->regulators[STMFTS_REGULATOR_VDD].supply = "vdd";
+	sdata->regulators[STMFTS_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, stmfts_power_off, sdata);
+	if (err)
+		return err;
+
+	sdata->client = client;
+
+	init_completion(&sdata->signal);
+
+	/*
+	 * Do not enable interrupts by default.
+	 * One possible case when an IRQ can be already rased is e.g. if the
+	 * regulator is set as always on and the stmfts device sends an IRQ as
+	 * soon as it gets powered, de-synchronizing the power on sequence.
+	 * During power on, the device will be reset and all the initialization
+	 * IRQ will be resent.
+	 */
+	irq_set_status_flags(client->irq, IRQ_NOAUTOEN);
+	err = devm_request_threaded_irq(&client->dev, client->irq,
+					NULL, stmfts_irq_handler,
+					IRQF_ONESHOT | IRQF_TRIGGER_LOW,
+					"stmfts_irq", sdata);
+	if (err)
+		return err;
+
+	dev_info(&client->dev, "initializing ST-Microelectronics FTS...\n");
+	err = stmfts_power_on(sdata);
+	if (err)
+		return err;
+
+	sdata->use_key = of_property_read_bool(client->dev.of_node,
+						"touch-key-connected");
+
+	sdata->input = devm_input_allocate_device(&client->dev);
+	if (!sdata->input)
+		return -ENOMEM;
+
+	sdata->input->name = STMFTS_DEV_NAME;
+	sdata->input->id.bustype = BUS_I2C;
+	sdata->input->open = stmfts_input_open;
+	sdata->input->close = stmfts_input_close;
+
+	touchscreen_parse_properties(sdata->input, true, &sdata->prop);
+
+	input_set_abs_params(sdata->input, ABS_MT_POSITION_X, 0,
+						sdata->prop.max_x, 0, 0);
+	input_set_abs_params(sdata->input, ABS_MT_POSITION_Y, 0,
+						sdata->prop.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_ORIENTATION, 0, 255, 0, 0);
+	input_set_abs_params(sdata->input, ABS_MT_PRESSURE, 0, 255, 0, 0);
+	input_set_abs_params(sdata->input, ABS_DISTANCE, 0, 255, 0, 0);
+
+	if (sdata->use_key) {
+		input_set_capability(sdata->input, EV_KEY, KEY_MENU);
+		input_set_capability(sdata->input, EV_KEY, KEY_BACK);
+	}
+
+	err = input_mt_init_slots(sdata->input,
+				STMFTS_MAX_FINGERS, INPUT_MT_DIRECT);
+	if (err)
+		return err;
+
+	input_set_drvdata(sdata->input, sdata);
+	err = input_register_device(sdata->input);
+	if (err)
+		return err;
+
+	if (sdata->use_key) {
+		err = stmfts_enable_led(sdata);
+		if (err) {
+			/* even if the LEDs have failed to be initialized and
+			 * used in the driver, I can still use the device even
+			 * without LEDs. The ledvdd regulator pointer will be
+			 * used as a flag.
+			 */
+			dev_warn(&client->dev,
+					"unable to use touchkey leds\n");
+			sdata->ledvdd = NULL;
+		}
+	}
+
+	err = sysfs_create_group(&sdata->client->dev.kobj,
+					&stmfts_attribute_group);
+	if (err)
+		return err;
+
+	pm_runtime_enable(&client->dev);
+
+	return 0;
+}
+
+static int stmfts_remove(struct i2c_client *client)
+{
+	pm_runtime_disable(&client->dev);
+	sysfs_remove_group(&client->dev.kobj, &stmfts_attribute_group);
+
+	return 0;
+}
+
+static int stmfts_runtime_suspend(struct device *dev)
+{
+	int ret;
+	struct stmfts_data *sdata = dev_get_drvdata(dev);
+
+	ret = i2c_smbus_write_byte(sdata->client, STMFTS_SLEEP_IN);
+	if (ret)
+		dev_warn(dev, "failed to suspend device\n");
+
+	return ret;
+}
+
+static int stmfts_runtime_resume(struct device *dev)
+{
+	int ret;
+	struct stmfts_data *sdata = dev_get_drvdata(dev);
+
+	ret = i2c_smbus_write_byte(sdata->client, STMFTS_SLEEP_OUT);
+	if (ret)
+		dev_err(dev, "failed to resume device\n");
+
+	return ret;
+}
+
+static int __maybe_unused stmfts_suspend(struct device *dev)
+{
+	struct stmfts_data *sdata = dev_get_drvdata(dev);
+
+	stmfts_power_off(sdata);
+
+	return 0;
+}
+
+static int __maybe_unused stmfts_resume(struct device *dev)
+{
+	struct stmfts_data *sdata = dev_get_drvdata(dev);
+
+	return stmfts_power_on(sdata);
+}
+
+static const struct dev_pm_ops stmfts_pm_ops = {
+	SET_SYSTEM_SLEEP_PM_OPS(stmfts_suspend, stmfts_resume)
+	SET_RUNTIME_PM_OPS(stmfts_runtime_suspend, stmfts_runtime_resume, NULL)
+};
+
+static const struct of_device_id stmfts_of_match[] = {
+	{ .compatible = "st,stmfts", },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, stmfts_of_match);
+
+static const struct i2c_device_id stmfts_id[] = {
+	{ "stmfts", 0 },
+	{ },
+};
+MODULE_DEVICE_TABLE(i2c, stmfts_id);
+
+static struct i2c_driver stmfts_driver = {
+	.driver = {
+		.name = STMFTS_DEV_NAME,
+		.of_match_table = of_match_ptr(stmfts_of_match),
+		.pm = &stmfts_pm_ops,
+	},
+	.probe = stmfts_probe,
+	.remove = stmfts_remove,
+	.id_table = stmfts_id,
+};
+
+module_i2c_driver(stmfts_driver);
+
+MODULE_AUTHOR("Andi Shyti <andi.shyti@...sung.com>");
+MODULE_DESCRIPTION("STMicroelectronics FTS Touch Screen");
+MODULE_LICENSE("GPL v2");
-- 
2.11.0

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