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@samsung.com>
Reviewed-by: Javier Martinez Canillas <javier@osg.samsung.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

4 files changed, 877 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/input/touchscreen/st,stmfts.txt b/Documentation/devicetree/bindings/input/touchscreen/st,stmfts.txt
new file mode 100644
index 000000000000..9683595cd0f5
--- /dev/null
+++ b/Documentation/devicetree/bindings/input/touchscreen/st,stmfts.txt
@@ -0,0 +1,43 @@
+* ST-Microelectronics FingerTip touchscreen controller
+
+The ST-Microelectronics FingerTip device provides a basic touchscreen
+functionality. Along with it the user can enable the touchkey which can work as
+a basic HOME and BACK key for phones.
+
+The driver supports also hovering as an absolute single touch event with x, y, z
+coordinates.
+
+Required properties:
+- compatible            : must be "st,stmfts"
+- reg                   : I2C slave address, (e.g. 0x49)
+- interrupt-parent      : the phandle to the interrupt controller which provides
+                          the interrupt
+- interrupts            : interrupt specification
+- avdd-supply           : analogic power supply
+- vdd-supply            : power supply
+- touchscreen-size-x    : see touchscreen.txt
+- touchscreen-size-y    : see touchscreen.txt
+
+Optional properties:
+- touch-key-connected   : specifies whether the touchkey feature is connected
+- ledvdd-supply         : power supply to the touch key leds
+
+Example:
+
+i2c@00000000 {
+
+        /* ... */
+
+        touchscreen@49 {
+                compatible = "st,stmfts";
+                reg = <0x49>;
+                interrupt-parent = <&gpa1>;
+                interrupts = <1 IRQ_TYPE_NONE>;
+                touchscreen-size-x = <1599>;
+                touchscreen-size-y = <2559>;
+                touch-key-connected;
+                avdd-supply = <&ldo30_reg>;
+                vdd-supply = <&ldo31_reg>;
+                ledvdd-supply = <&ldo33_reg>;
+        };
+};
diff --git a/drivers/input/touchscreen/Kconfig b/drivers/input/touchscreen/Kconfig
index cf26ca49ae6d..64b30fe273fd 100644
--- a/drivers/input/touchscreen/Kconfig
+++ b/drivers/input/touchscreen/Kconfig
@@ -1114,6 +1114,17 @@ 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 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..802d0e82d034
--- /dev/null
+++ b/drivers/input/touchscreen/stmfts.c
@@ -0,0 +1,822 @@
+/*
+ * 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.
+ *
+ * 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];
+
+        /*
+         * Presence of 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 cmd_done;
+
+        bool use_key;
+        bool led_status;
+        bool hover_enabled;
+        bool running;
+};
+
+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);
+        int err;
+
+        if (value == sdata->led_status || !sdata->ledvdd)
+                return;
+
+        if (!value) {
+                regulator_disable(sdata->ledvdd);
+        } else {
+                err = regulator_enable(sdata->ledvdd);
+                if (err)
+                        dev_warn(&sdata->client->dev,
+                                 "failed to disable ledvdd regulator: %d\n",
+                                 err);
+        }
+
+        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);
+}
+
+/*
+ * We can't simply use i2c_smbus_read_i2c_block_data because we
+ * need to read more than 255 bytes (
+ */
+static int stmfts_read_events(struct stmfts_data *sdata)
+{
+        u8 cmd = STMFTS_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    = STMFTS_DATA_MAX_SIZE,
+                        .buf    = sdata->data,
+                },
+        };
+        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 stmfts_report_contact_event(struct stmfts_data *sdata,
+                                        const u8 event[])
+{
+        u8 slot_id = (event[0] & STMFTS_MASK_TOUCH_ID) >> 4;
+        u16 x = event[1] | ((event[2] & STMFTS_MASK_X_MSB) << 8);
+        u16 y = (event[2] >> 4) | (event[3] << 4);
+        u8 maj = event[4];
+        u8 min = event[5];
+        u8 orientation = event[6];
+        u8 area = event[7];
+
+        input_mt_slot(sdata->input, slot_id);
+
+        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, 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);
+}
+
+static void stmfts_report_contact_release(struct stmfts_data *sdata,
+                                          const u8 event[])
+{
+        u8 slot_id = (event[0] & STMFTS_MASK_TOUCH_ID) >> 4;
+
+        input_mt_slot(sdata->input, slot_id);
+        input_mt_report_slot_state(sdata->input, MT_TOOL_FINGER, false);
+
+        input_sync(sdata->input);
+}
+
+static void stmfts_report_hover_event(struct stmfts_data *sdata,
+                                      const u8 event[])
+{
+        u16 x = (event[2] << 4) | (event[4] >> 4);
+        u16 y = (event[3] << 4) | (event[4] & STMFTS_MASK_Y_LSB);
+        u8 z = event[5];
+
+        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);
+}
+
+static void stmfts_report_key_event(struct stmfts_data *sdata, const u8 event[])
+{
+        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: %#02x\n", event[2]);
+                break;
+        }
+
+        input_sync(sdata->input);
+}
+
+static void stmfts_parse_events(struct stmfts_data *sdata)
+{
+        int i;
+
+        for (i = 0; i < STMFTS_STACK_DEPTH; i++) {
+                u8 *event = &sdata->data[i * STMFTS_EVENT_SIZE];
+
+                switch (event[0]) {
+
+                case STMFTS_EV_CONTROLLER_READY:
+                case STMFTS_EV_SLEEP_OUT_CONTROLLER_READY:
+                case STMFTS_EV_STATUS:
+                        complete(&sdata->cmd_done);
+                        /* fall through */
+
+                case STMFTS_EV_NO_EVENT:
+                case STMFTS_EV_DEBUG:
+                        return;
+                }
+
+                switch (event[0] & STMFTS_MASK_EVENT_ID) {
+
+                case STMFTS_EV_MULTI_TOUCH_ENTER:
+                case STMFTS_EV_MULTI_TOUCH_MOTION:
+                        stmfts_report_contact_event(sdata, event);
+                        break;
+
+                case STMFTS_EV_MULTI_TOUCH_LEAVE:
+                        stmfts_report_contact_release(sdata, event);
+                        break;
+
+                case STMFTS_EV_HOVER_ENTER:
+                case STMFTS_EV_HOVER_LEAVE:
+                case STMFTS_EV_HOVER_MOTION:
+                        stmfts_report_hover_event(sdata, event);
+                        break;
+
+                case STMFTS_EV_KEY_STATUS:
+                        stmfts_report_key_event(sdata, event);
+                        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 %#02x\n", event[0]);
+                }
+        }
+}
+
+static irqreturn_t stmfts_irq_handler(int irq, void *dev)
+{
+        struct stmfts_data *sdata = dev;
+        int err;
+
+        mutex_lock(&sdata->mutex);
+
+        err = stmfts_read_events(sdata);
+        if (unlikely(err))
+                dev_err(&sdata->client->dev,
+                        "failed to read events: %d\n", err);
+        else
+                stmfts_parse_events(sdata);
+
+        mutex_unlock(&sdata->mutex);
+        return IRQ_HANDLED;
+}
+
+static int stmfts_command(struct stmfts_data *sdata, const u8 cmd)
+{
+        int err;
+
+        reinit_completion(&sdata->cmd_done);
+
+        err = i2c_smbus_write_byte(sdata->client, cmd);
+        if (err)
+                return err;
+
+        if (!wait_for_completion_timeout(&sdata->cmd_done,
+                                         msecs_to_jiffies(1000)))
+                return -ETIMEDOUT;
+
+        return 0;
+}
+
+static int stmfts_input_open(struct input_dev *dev)
+{
+        struct stmfts_data *sdata = input_get_drvdata(dev);
+        int err;
+
+        err = pm_runtime_get_sync(&sdata->client->dev);
+        if (err < 0)
+                return err;
+
+        err = i2c_smbus_write_byte(sdata->client, STMFTS_MS_MT_SENSE_ON);
+        if (err)
+                return err;
+
+        mutex_lock(&sdata->mutex);
+        sdata->running = true;
+
+        if (sdata->hover_enabled) {
+                err = i2c_smbus_write_byte(sdata->client,
+                                           STMFTS_SS_HOVER_SENSE_ON);
+                if (err)
+                        dev_warn(&sdata->client->dev,
+                                 "failed to enable hover\n");
+        }
+        mutex_unlock(&sdata->mutex);
+
+        if (sdata->use_key) {
+                err = i2c_smbus_write_byte(sdata->client,
+                                           STMFTS_MS_KEY_SENSE_ON);
+                if (err)
+                        /* 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)
+{
+        struct stmfts_data *sdata = input_get_drvdata(dev);
+        int err;
+
+        err = i2c_smbus_write_byte(sdata->client, STMFTS_MS_MT_SENSE_OFF);
+        if (err)
+                dev_warn(&sdata->client->dev,
+                         "failed to disable touchscreen: %d\n", err);
+
+        mutex_lock(&sdata->mutex);
+
+        sdata->running = false;
+
+        if (sdata->hover_enabled) {
+                err = i2c_smbus_write_byte(sdata->client,
+                                           STMFTS_SS_HOVER_SENSE_OFF);
+                if (err)
+                        dev_warn(&sdata->client->dev,
+                                 "failed to disable hover: %d\n", err);
+        }
+        mutex_unlock(&sdata->mutex);
+
+        if (sdata->use_key) {
+                err = i2c_smbus_write_byte(sdata->client,
+                                           STMFTS_MS_KEY_SENSE_OFF);
+                if (err)
+                        dev_warn(&sdata->client->dev,
+                                 "failed to disable touchkey: %d\n", err);
+        }
+
+        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, "%#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, "%#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 err;
+
+        err = i2c_smbus_read_i2c_block_data(sdata->client, STMFTS_READ_STATUS,
+                                            sizeof(status), status);
+        if (err)
+                return err;
+
+        return sprintf(buf, "%#02x\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)
+{
+        struct stmfts_data *sdata = dev_get_drvdata(dev);
+        unsigned long value;
+        int err = 0;
+
+        if (kstrtoul(buf, 0, &value))
+                return -EINVAL;
+
+        mutex_lock(&sdata->mutex);
+
+        if (value & sdata->hover_enabled)
+                goto out;
+
+        if (sdata->running)
+                err = i2c_smbus_write_byte(sdata->client,
+                                           value ? STMFTS_SS_HOVER_SENSE_ON :
+                                                   STMFTS_SS_HOVER_SENSE_OFF);
+
+        if (!err)
+                sdata->hover_enabled = !!value;
+
+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,
+                                            sizeof(reg), reg);
+        if (err < 0)
+                return err;
+        if (err != sizeof(reg))
+                return -EIO;
+
+        sdata->chip_id = be16_to_cpup((__be16 *)&reg[6]);
+        sdata->chip_ver = reg[0];
+        sdata->fw_ver = be16_to_cpup((__be16 *)&reg[2]);
+        sdata->config_id = reg[4];
+        sdata->config_ver = reg[5];
+
+        enable_irq(sdata->client->irq);
+
+        msleep(50);
+
+        err = stmfts_command(sdata, STMFTS_SYSTEM_RESET);
+        if (err)
+                return err;
+
+        err = stmfts_command(sdata, STMFTS_SLEEP_OUT);
+        if (err)
+                return err;
+
+        /* optional tuning */
+        err = stmfts_command(sdata, STMFTS_MS_CX_TUNING);
+        if (err)
+                dev_warn(&sdata->client->dev,
+                         "failed to perform mutual auto tune: %d\n", err);
+
+        /* optional tuning */
+        err = stmfts_command(sdata, STMFTS_SS_CX_TUNING);
+        if (err)
+                dev_warn(&sdata->client->dev,
+                         "failed to perform self auto tune: %d\n", err);
+
+        err = stmfts_command(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
+         */
+        (void) 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;
+
+        sdata = devm_kzalloc(&client->dev, sizeof(*sdata), GFP_KERNEL);
+        if (!sdata)
+                return -ENOMEM;
+
+        i2c_set_clientdata(client, sdata);
+
+        sdata->client = client;
+        mutex_init(&sdata->mutex);
+        init_completion(&sdata->cmd_done);
+
+        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;
+
+        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);
+
+        sdata->use_key = device_property_read_bool(&client->dev,
+                                                   "touch-key-connected");
+        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 = devm_request_threaded_irq(&client->dev, client->irq,
+                                        NULL, stmfts_irq_handler,
+                                        IRQF_ONESHOT,
+                                        "stmfts_irq", sdata);
+        if (err)
+                return err;
+
+        /* stmfts_power_on expects interrupt to be disabled */
+        disable_irq(client->irq);
+
+        dev_dbg(&client->dev, "initializing ST-Microelectronics FTS...\n");
+
+        err = stmfts_power_on(sdata);
+        if (err)
+                return err;
+
+        err = devm_add_action_or_reset(&client->dev, stmfts_power_off, sdata);
+        if (err)
+                return err;
+
+        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)
+{
+        struct stmfts_data *sdata = dev_get_drvdata(dev);
+        int ret;
+
+        ret = i2c_smbus_write_byte(sdata->client, STMFTS_SLEEP_IN);
+        if (ret)
+                dev_warn(dev, "failed to suspend device: %d\n", ret);
+
+        return ret;
+}
+
+static int stmfts_runtime_resume(struct device *dev)
+{
+        struct stmfts_data *sdata = dev_get_drvdata(dev);
+        int ret;
+
+        ret = i2c_smbus_write_byte(sdata->client, STMFTS_SLEEP_OUT);
+        if (ret)
+                dev_err(dev, "failed to resume device: %d\n", ret);
+
+        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)
+};
+
+#ifdef CONFIG_OF
+static const struct of_device_id stmfts_of_match[] = {
+        { .compatible = "st,stmfts", },
+        { },
+};
+MODULE_DEVICE_TABLE(of, stmfts_of_match);
+#endif
+
+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@samsung.com>");
+MODULE_DESCRIPTION("STMicroelectronics FTS Touch Screen");
+MODULE_LICENSE("GPL v2");