[PATCH WIP v3 08/11] Input: stmfts - add optional reset GPIO support

[David Heidelberg via B4 Relay <devnull+david.ixit.cz@kernel.org>]

From: Petr Hodina <petr.hodina@protonmail.com>

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>
---
 drivers/input/touchscreen/stmfts.c | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/drivers/input/touchscreen/stmfts.c b/drivers/input/touchscreen/stmfts.c
index 5f7de5e687da2..04110006f54a0 100644
--- a/drivers/input/touchscreen/stmfts.c
+++ b/drivers/input/touchscreen/stmfts.c
@@ -77,6 +77,7 @@ 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 +540,15 @@ 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_power_on(struct stmfts_data *sdata)
 {
 	int err;
@@ -548,6 +558,9 @@ static int stmfts_power_on(struct stmfts_data *sdata)
 	if (err)
 		return err;
 
+	if (sdata->reset_gpio)
+		stmfts_reset(sdata);
+
 	/*
 	 * The datasheet does not specify the power on time, but considering
 	 * that the reset time is < 10ms, I sleep 20ms to be sure
@@ -606,6 +619,10 @@ 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);
 }
@@ -662,6 +679,12 @@ 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;

-- 
2.53.0