Re: [PATCH 2/3] Input: add support for the STMicroelectronics FingerTip touchscreen

From: Dmitry Torokhov
Date: Tue Jan 17 2017 - 16:25:36 EST


Hi Andi.

On Tue, Jan 17, 2017 at 10:54:40PM +0900, Andi Shyti wrote:
> 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, z. The z coordinate is
> related to the distance between the finger and the touchscreen
> itself.

No, we have dedicated ABS_DISTANCE event code for this, not ABS_Z.

>
> 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@xxxxxxxxxxx>
> ---
> drivers/input/touchscreen/Kconfig | 12 +
> drivers/input/touchscreen/Makefile | 1 +
> drivers/input/touchscreen/stmfts.c | 759 +++++++++++++++++++++++++++++++++++++
> 3 files changed, 772 insertions(+)
> create mode 100644 drivers/input/touchscreen/stmfts.c
>
> diff --git a/drivers/input/touchscreen/Kconfig b/drivers/input/touchscreen/Kconfig
> index 8650c94e29d0..18c2f919eb79 100644
> --- a/drivers/input/touchscreen/Kconfig
> +++ b/drivers/input/touchscreen/Kconfig
> @@ -1092,6 +1092,18 @@ 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 e41e3c7aa427..be7673f9c71a 100644
> --- a/drivers/input/touchscreen/Makefile
> +++ b/drivers/input/touchscreen/Makefile
> @@ -66,6 +66,7 @@ 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..abccc14d06d2
> --- /dev/null
> +++ b/drivers/input/touchscreen/stmfts.c
> @@ -0,0 +1,759 @@
> +/*
> + * Copyright (c) 2017 Samsung Electronics Co., Ltd.
> + * Author: Andi Shyti <andi.shyti@xxxxxxxxxxx>
> + *
> + * 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.h>
> +#include <linux/input/mt.h>
> +#include <linux/interrupt.h>
> +#include <linux/leds.h>
> +#include <linux/module.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_SLEEP_IN 0x91
> +#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
> +
> +/* 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_BACK 0x01
> +#define STMFTS_MASK_KEY_MENU 0x02
> +
> +#define STMFTS_EVENT_SIZE 8
> +#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_touch;
> + struct input_dev *input_key;
> + struct led_classdev led_cdev;
> + struct mutex mutex;
> + u32 x_size;
> + u32 y_size;
> +
> + struct regulator_bulk_data regulators[2];
> +
> + /* ledvdd will be used also to check
> + * whether the LED is supported
> + */
> + struct regulator *ledvdd;
> +
> + bool use_key;
> + bool signal;
> + bool led_status;
> + u8 users;
> +
> + u16 chip_id;
> + u8 chip_ver;
> + u16 fw_ver;
> + u8 config_id;
> + u8 config_ver;
> + u8 in_touch;
> +
> + wait_queue_head_t wq;
> +
> + bool hover_enabled;
> +};
> +
> +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)
> + 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 event[])
> +{
> + int ret;
> + u8 id, t_id = 0;
> + u16 x, y, z, maj, min, orientation, area;
> +
> + id = event[0];
> +
> + do {
> + mutex_lock(&sdata->mutex);
> + if (sdata->in_touch) {
> + id = event[0] & STMFTS_MASK_EVENT_ID;
> + t_id = (event[0] & STMFTS_MASK_TOUCH_ID) >> 4;
> + } else {
> + id = event[0];
> + t_id = 0;
> + }
> +
> + switch (id) {
> + case STMFTS_EV_NO_EVENT:
> + break;
> +
> + 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) {
> + if (!(sdata->in_touch++))
> + input_mt_report_slot_state(
> + sdata->input_touch,
> + MT_TOOL_FINGER, true);
> + } else if (id == STMFTS_EV_MULTI_TOUCH_LEAVE) {
> + if (!(--sdata->in_touch))
> + input_mt_report_slot_state(
> + sdata->input_touch,
> + 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_touch, t_id);
> + input_report_abs(sdata->input_touch,
> + ABS_MT_POSITION_X, x);
> + input_report_abs(sdata->input_touch,
> + ABS_MT_POSITION_Y, y);
> + input_report_abs(sdata->input_touch,
> + ABS_MT_TOUCH_MAJOR, maj);
> + input_report_abs(sdata->input_touch,
> + ABS_MT_TOUCH_MINOR, min);
> + input_report_abs(sdata->input_touch,
> + ABS_MT_PRESSURE, area);
> + input_report_abs(sdata->input_touch,
> + ABS_MT_ORIENTATION, orientation);
> + input_sync(sdata->input_touch);
> +
> + 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_touch, ABS_X, x);
> + input_report_abs(sdata->input_touch, ABS_Y, y);
> + input_report_abs(sdata->input_touch, ABS_Z, z);
> + input_sync(sdata->input_touch);
> +
> + break;
> +
> + case STMFTS_EV_KEY_STATUS:

Please use:
switch (event[2]) {
case 0:
...

case STMFTS_MASK_KEY_BACK:
...

case STMFTS_MASK_KEY_MENU:
...

default:
dev_warn(...);
break;
}

> + if (!event[2]) {
> + input_report_key(sdata->input_key, KEY_BACK, 0);
> + input_report_key(sdata->input_key, KEY_MENU, 0);
> + } else {
> + if (event[2] == STMFTS_MASK_KEY_BACK)
> + input_report_key(sdata->input_key,
> + KEY_BACK, 1);
> + else if (event[2] == STMFTS_MASK_KEY_MENU)
> + input_report_key(sdata->input_key,
> + KEY_MENU, 1);
> + else /* quite impossible */
> + break;
> + }
> + input_sync(sdata->input_key);
> + break;
> +
> + case STMFTS_EV_STATUS:
> + sdata->signal = true;
> + wake_up_interruptible(&sdata->wq);
> + break;
> +
> + case STMFTS_EV_ERROR:
> + dev_err(&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]);
> + }
> + mutex_unlock(&sdata->mutex);
> +
> + ret = i2c_smbus_read_i2c_block_data(sdata->client,
> + STMFTS_READ_ONE_EVENT,
> + STMFTS_EVENT_SIZE, event);
> + if (ret) {
> + i2c_smbus_write_byte(sdata->client,
> + STMFTS_CLEAR_EVENT_STACK);
> + break;
> + }
> +
> + } while (event[0]);
> +}
> +
> +static irqreturn_t stmfts_irq_handler(int irq, void *dev)
> +{
> + struct stmfts_data *sdata = dev;
> + int ret;
> + u8 event[STMFTS_EVENT_SIZE];
> +
> + ret = i2c_smbus_read_i2c_block_data(sdata->client,
> + STMFTS_READ_ONE_EVENT,
> + STMFTS_EVENT_SIZE, event);
> +
> + switch (event[0]) {
> + case STMFTS_EV_CONTROLLER_READY:
> + case STMFTS_EV_SLEEP_OUT_CONTROLLER_READY:
> + sdata->signal = true;
> + wake_up_interruptible(&sdata->wq);
> + break;
> + default:
> + stmfts_parse_event(sdata, event);
> + }
> +
> + 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;
> +
> + sdata->signal = false;

This is racy, interrupt may run before you get chance to set signal to
false. Also, please use wait_for_completion*() API.

> + err = wait_event_interruptible_timeout(sdata->wq, sdata->signal,
> + msecs_to_jiffies(1000));
> +
> + return !err ? -ETIMEDOUT : 0;
> +}
> +
> +static void stmfts_sleep_in(struct stmfts_data *sdata)
> +{
> + mutex_lock(&sdata->mutex);
> +
> + sdata->users--;
> + if (!sdata->users)
> + i2c_smbus_write_byte(sdata->client, STMFTS_SLEEP_IN);

This looks like somewhat homegrown runtime PM, please replace.

> +
> + mutex_unlock(&sdata->mutex);
> +}
> +
> +static int stmfts_sleep_out(struct stmfts_data *sdata, u8 cmd)
> +{
> + int ret = 0;
> +
> + mutex_lock(&sdata->mutex);
> +
> + if (!sdata->users)
> + ret = stmfts_write_and_wait(sdata, STMFTS_SLEEP_OUT);
> +
> + /* if sleep out succeeds users increments, otherwise not */
> + sdata->users += !ret;
> +
> + mutex_unlock(&sdata->mutex);
> +
> + ret = i2c_smbus_write_byte(sdata->client, cmd);
> + if (ret)
> + stmfts_sleep_in(sdata);
> +
> + return ret;
> +}
> +
> +static int stmfts_input_touch_open(struct input_dev *dev)
> +{
> + struct stmfts_data *sdata = input_get_drvdata(dev);
> +
> + return stmfts_sleep_out(sdata, STMFTS_MS_MT_SENSE_ON);
> +}
> +
> +static void stmfts_input_touch_close(struct input_dev *dev)
> +{
> + struct stmfts_data *sdata = input_get_drvdata(dev);
> +
> + i2c_smbus_write_byte(sdata->client, STMFTS_MS_MT_SENSE_OFF);
> +
> + stmfts_sleep_in(sdata);
> +}
> +
> +static int stmfts_input_key_open(struct input_dev *dev)
> +{
> + struct stmfts_data *sdata = input_get_drvdata(dev);
> +
> + return stmfts_sleep_out(sdata, STMFTS_MS_KEY_SENSE_ON);
> +}
> +
> +static void stmfts_input_key_close(struct input_dev *dev)
> +{
> + struct stmfts_data *sdata = input_get_drvdata(dev);
> +
> + i2c_smbus_write_byte(sdata->client, STMFTS_MS_KEY_SENSE_OFF);
> + stmfts_sleep_in(sdata);
> +}
> +
> +static ssize_t stmfts_sysfs_hwid(struct device *dev,
> + struct device_attribute *attr, char *buf)
> +{
> + struct stmfts_data *sdata = dev_get_drvdata(dev);
> +
> + return sprintf(buf, "ST-Microelectronics FTS 0x%x version %u\n",
> + sdata->chip_id, sdata->chip_ver);

sysfs attributes should have only 1 value. Please split into chip ID and
chip version and drop static strings.

> +}
> +
> +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 version %u\n",
> + sdata->config_id, sdata->config_ver);

Please split in 2.

> +}
> +
> +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;
> +
> + if (value & sdata->hover_enabled)
> + return len;
> +
> + if (value) {
> + err = stmfts_sleep_out(sdata, STMFTS_SS_HOVER_SENSE_ON);

Why setting hover explicitly wakes up controller? You shuld put it back
into sleep if nobody is listening, or postpone programming until there
are users.

> + sdata->hover_enabled = !err;
> + } else {
> + err = i2c_smbus_write_byte(sdata->client,
> + STMFTS_SS_HOVER_SENSE_OFF);
> + stmfts_sleep_in(sdata);
> + sdata->hover_enabled = !!err;
> + }
> +
> + return len;
> +}
> +
> +static DEVICE_ATTR(hwid, 0444, stmfts_sysfs_hwid, 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(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_hwid.attr,
> + &dev_attr_fw_ver.attr,
> + &dev_attr_config_id.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_parse_dt(struct stmfts_data *sdata)
> +{
> + int ret;
> + struct device_node *np = sdata->client->dev.of_node;
> +
> + if (!np)
> + return -ENOENT;
> +
> + ret = of_property_read_u32(np, "touchscreen-size-x", &sdata->x_size);
> + if (ret)
> + return ret;
> +
> + ret = of_property_read_u32(np, "touchscreen-size-y", &sdata->y_size);
> + if (ret)
> + return ret;

Please use touchscreen_parse_properties().

> +
> + sdata->use_key = of_property_read_bool(np, "touch-key-connected");
> +
> + return 0;
> +}
> +
> +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];
> +
> + 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;

Hmm, do you need to calibrate on boot, or maybe wait for the device to
be opened first?

> +
> + /* 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);
> +}
> +
> +static int stmfts_enable_key(struct stmfts_data *sdata)
> +{
> + int err;
> +
> + sdata->input_key = devm_input_allocate_device(&sdata->client->dev);
> + if (!sdata->input_key)
> + return -ENOMEM;
> +
> + sdata->input_key->name = "stmfts_key";
> + sdata->input_key->id.bustype = BUS_I2C;
> + sdata->input_key->open = stmfts_input_key_open;
> + sdata->input_key->close = stmfts_input_key_close;

If you want separate input device for keys I'd recommend setting ->phys
on them. Another option is to add keys to teh touchscreen device. Do you
expect different actors listening to these devices? Even with different
actors you can program event masks so that if process is not interested
in some events (like ABS_MT_* events) it is not woken up when dveice
generates them.

> +
> + input_set_capability(sdata->input_key, EV_KEY, KEY_MENU);
> + input_set_capability(sdata->input_key, EV_KEY, KEY_BACK);
> +
> + input_set_drvdata(sdata->input_key, sdata);
> + err = input_register_device(sdata->input_key);
> + if (err)
> + return err;
> +
> + /* get the regulator for powering the leds on */
> + sdata->ledvdd = devm_regulator_get(&sdata->client->dev, "ledvdd");
> + if (IS_ERR(sdata->ledvdd))
> + /* there is no LED connected to the touch key */
> + sdata->ledvdd = NULL;

As I mentioned, is it truly regulator, or just a GPIO?

> +
> + 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) {
> + dev_warn(&sdata->client->dev, "unable to register led, led might not work\n");
> + sdata->ledvdd = NULL;
> +
> + /* I don't want to prevent using the touch key
> + * only because the LEDs don't get registered
> + */
> + err = 0;
> + }
> +
> + return err;
> +}
> +
> +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);
> +
> + 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;
> +
> + err = stmfts_parse_dt(sdata);
> + if (err)
> + return err;
> +
> + init_waitqueue_head(&sdata->wq);
> +
> + err = sysfs_create_group(&sdata->client->dev.kobj,
> + &stmfts_attribute_group);

I do not see it being removed on errors.

> + if (err)
> + return err;
> +
> + 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;

What happens if interrupt is raised here?

> +
> + disable_irq(sdata->client->irq);
> +
> + dev_info(&client->dev, "initializing ST-Microelectronics FTS...\n");
> + err = stmfts_power_on(sdata);
> + if (err)
> + return err;
> +
> + sdata->input_touch = devm_input_allocate_device(&client->dev);
> + if (!sdata->input_touch)
> + return -ENOMEM;
> +
> + sdata->input_touch->name = STMFTS_DEV_NAME;
> + sdata->input_touch->id.bustype = BUS_I2C;
> + sdata->input_touch->open = stmfts_input_touch_open;
> + sdata->input_touch->close = stmfts_input_touch_close;
> +
> + input_set_capability(sdata->input_touch, EV_ABS, ABS_MT_POSITION_Y);
> + input_set_capability(sdata->input_touch, EV_ABS, ABS_MT_POSITION_X);
> + input_set_capability(sdata->input_touch, EV_ABS, ABS_MT_TOUCH_MAJOR);
> + input_set_capability(sdata->input_touch, EV_ABS, ABS_MT_TOUCH_MINOR);
> + input_set_capability(sdata->input_touch, EV_ABS, ABS_MT_ORIENTATION);
> + input_set_capability(sdata->input_touch, EV_ABS, ABS_MT_PRESSURE);
> + input_set_capability(sdata->input_touch, EV_ABS, ABS_MT_POSITION_X);
> +
> + input_set_abs_params(sdata->input_touch,
> + ABS_MT_POSITION_X, 0, sdata->x_size, 0, 0);

input_set_abs_params() implies input_set_capability(), you can drop the
calls above.

> + input_set_abs_params(sdata->input_touch,
> + ABS_MT_POSITION_Y, 0, sdata->y_size, 0, 0);
> + input_set_abs_params(sdata->input_touch,
> + ABS_MT_TOUCH_MAJOR, 0, 255, 0, 0);
> + input_set_abs_params(sdata->input_touch,
> + ABS_MT_TOUCH_MINOR, 0, 255, 0, 0);
> + input_set_abs_params(sdata->input_touch,
> + ABS_MT_ORIENTATION, 0, 255, 0, 0);
> + input_set_abs_params(sdata->input_touch,
> + ABS_MT_PRESSURE, 0, 255, 0, 0);
> + input_mt_init_slots(sdata->input_touch,
> + STMFTS_MAX_FINGERS, INPUT_MT_DIRECT);

Error handling please.

> +
> + /* for hover features */
> + input_set_capability(sdata->input_touch, EV_ABS, ABS_X);
> + input_set_capability(sdata->input_touch, EV_ABS, ABS_Y);

Not needed, input_mt_init_slots() will copy MT axis setup into ST axis
for INPUT_MT_DIRECT devices.

> + input_set_capability(sdata->input_touch, EV_ABS, ABS_Z);

ABS_DISTANCE

> + input_set_abs_params(sdata->input_touch, ABS_X, 0, sdata->x_size, 0, 0);
> + input_set_abs_params(sdata->input_touch, ABS_Y, 0, sdata->y_size, 0, 0);
> + input_set_abs_params(sdata->input_touch, ABS_Z, 0, 255, 0, 0);
> +
> + input_set_drvdata(sdata->input_touch, sdata);
> + err = input_register_device(sdata->input_touch);
> + if (err)
> + return err;
> +
> + if (sdata->use_key) {
> + err = stmfts_enable_key(sdata);
> + if (err)
> + dev_warn(&client->dev, "failed to enable touchkey\n");
> + }
> +
> + return 0;
> +}
> +
> +static int stmfts_remove(struct i2c_client *client)
> +{
> + struct stmfts_data *sdata = i2c_get_clientdata(client);
> +
> + sysfs_remove_group(&sdata->client->dev.kobj, &stmfts_attribute_group);
> +
> + return 0;
> +}
> +
> +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 SIMPLE_DEV_PM_OPS(stmfts_pm_ops, stmfts_suspend, stmfts_resume);
> +
> +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@xxxxxxxxxxx>");
> +MODULE_DESCRIPTION("STMicroelectronics FTS Touch Screen");
> +MODULE_LICENSE("GPL v2");
> --
> 2.11.0
>

Thanks.

--
Dmitry