Input: stmfts - add optional reset GPIO support

Add support for an optional "reset-gpios" property. If present, the
driver drives the reset line high at probe time and releases it during
power-on, after the regulators have been enabled.

Signed-off-by: Petr Hodina <petr.hodina@protonmail.com>
Co-developed-by: David Heidelberg <david@ixit.cz>
Signed-off-by: David Heidelberg <david@ixit.cz>
Link: https://patch.msgid.link/20260409-stmfts5-v4-8-64fe62027db5@ixit.cz
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

diff --git a/drivers/input/touchscreen/stmfts.c b/drivers/input/touchscreen/stmfts.c
index 1955419a0db53964f672766af74bfd67cfe9f531..43158d03ecc1cb36a9479e9b22295ad7749cfe94 100644 (file)
--- a/drivers/input/touchscreen/stmfts.c
+++ b/drivers/input/touchscreen/stmfts.c
@@ -5,6 +5,7 @@
 // Copyright (c) 2017 Andi Shyti <andi@etezian.org>
 
 #include <linux/delay.h>
+#include <linux/gpio/consumer.h>
 #include <linux/i2c.h>
 #include <linux/input/mt.h>
 #include <linux/input/touchscreen.h>
@@ -77,6 +78,7 @@ static const struct regulator_bulk_data stmfts_supplies[] = {
 struct stmfts_data {
        struct i2c_client *client;
        struct input_dev *input;
+       struct gpio_desc *reset_gpio;
        struct led_classdev led_cdev;
        struct mutex mutex;
 
@@ -539,6 +541,15 @@ static int stmfts_read_system_info(struct stmfts_data *sdata)
        return 0;
 }
 
+static void stmfts_reset(struct stmfts_data *sdata)
+{
+       gpiod_set_value_cansleep(sdata->reset_gpio, 1);
+       msleep(20);
+
+       gpiod_set_value_cansleep(sdata->reset_gpio, 0);
+       msleep(50);
+}
+
 static int stmfts_configure(struct stmfts_data *sdata)
 {
        int err;
@@ -585,6 +596,9 @@ static int stmfts_power_on(struct stmfts_data *sdata)
         */
        msleep(20);
 
+       if (sdata->reset_gpio)
+               stmfts_reset(sdata);
+
        err = stmfts_read_system_info(sdata);
        if (err)
                goto err_disable_regulators;
@@ -617,6 +631,10 @@ static void stmfts_power_off(void *data)
        struct stmfts_data *sdata = data;
 
        disable_irq(sdata->client->irq);
+
+       if (sdata->reset_gpio)
+               gpiod_set_value_cansleep(sdata->reset_gpio, 1);
+
        regulator_bulk_disable(ARRAY_SIZE(stmfts_supplies), sdata->supplies);
 }
 
@@ -672,6 +690,11 @@ static int stmfts_probe(struct i2c_client *client)
        if (err)
                return err;
 
+       sdata->reset_gpio = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH);
+       if (IS_ERR(sdata->reset_gpio))
+               return dev_err_probe(dev, PTR_ERR(sdata->reset_gpio),
+                                    "Failed to get GPIO 'reset'\n");
+
        sdata->input = devm_input_allocate_device(dev);
        if (!sdata->input)
                return -ENOMEM;