Commit c3a39380 authored by Richard Leitner's avatar Richard Leitner Committed by Dmitry Torokhov
Browse files

Input: sx8654 - add reset-gpio support 



The sx8654 features a NRST input which may be connected to a GPIO.
Therefore add support for hard-resetting the sx8654 via this NRST.

If the reset-gpio property is provided the sx8654 is resetted via NRST
instead of the soft-reset via I2C.

Signed-off-by: default avatarRichard Leitner <richard.leitner@skidata.com>
Reviewed-by: default avatarRob Herring <robh@kernel.org>
Signed-off-by: default avatarDmitry Torokhov <dmitry.torokhov@gmail.com>
parent 4dbb7119

Documentation/devicetree/bindings/input/touchscreen/sx8654.txt

+4 −0
Original line number Diff line number Diff line
@@ -5,6 +5,9 @@ Required properties: 
- reg: i2c slave address

- interrupts: touch controller interrupt



Optional properties:

 - reset-gpios: GPIO specification for the NRST input



Example:



	sx8654@48 {
@@ -12,4 +15,5 @@ Example: 
		reg = <0x48>;

		interrupt-parent = <&gpio6>;

		interrupts = <3 IRQ_TYPE_EDGE_FALLING>;

		reset-gpios = <&gpio4 2 GPIO_ACTIVE_LOW>;

	};

drivers/input/touchscreen/sx8654.c

+38 −6
Original line number Diff line number Diff line
@@ -27,12 +27,14 @@ 
 *  published by the Free Software Foundation.

 */



#include <linux/input.h>

#include <linux/module.h>

#include <linux/of.h>

#include <linux/delay.h>

#include <linux/gpio/consumer.h>

#include <linux/i2c.h>

#include <linux/input.h>

#include <linux/interrupt.h>

#include <linux/irq.h>

#include <linux/module.h>

#include <linux/of.h>



/* register addresses */

#define I2C_REG_TOUCH0			0x00
@@ -74,6 +76,7 @@ 
struct sx8654 {

	struct input_dev *input;

	struct i2c_client *client;

	struct gpio_desc *gpio_reset;

};



static irqreturn_t sx8654_irq(int irq, void *handle)
@@ -124,6 +127,25 @@ out: 
	return IRQ_HANDLED;

}



static int sx8654_reset(struct sx8654 *ts)

{

	int err;



	if (ts->gpio_reset) {

		gpiod_set_value_cansleep(ts->gpio_reset, 1);

		udelay(2); /* Tpulse > 1µs */

		gpiod_set_value_cansleep(ts->gpio_reset, 0);

	} else {

		dev_dbg(&ts->client->dev, "NRST unavailable, try softreset\n");

		err = i2c_smbus_write_byte_data(ts->client, I2C_REG_SOFTRESET,

						SOFTRESET_VALUE);

		if (err)

			return err;

	}



	return 0;

}



static int sx8654_open(struct input_dev *dev)

{

	struct sx8654 *sx8654 = input_get_drvdata(dev);
@@ -186,6 +208,17 @@ static int sx8654_probe(struct i2c_client *client, 
	if (!sx8654)

		return -ENOMEM;



	sx8654->gpio_reset = devm_gpiod_get_optional(&client->dev, "reset",

						     GPIOD_OUT_HIGH);

	if (IS_ERR(sx8654->gpio_reset)) {

		error = PTR_ERR(sx8654->gpio_reset);

		if (error != -EPROBE_DEFER)

			dev_err(&client->dev, "unable to get reset-gpio: %d\n",

				error);

		return error;

	}

	dev_dbg(&client->dev, "got GPIO reset pin\n");



	input = devm_input_allocate_device(&client->dev);

	if (!input)

		return -ENOMEM;
@@ -206,10 +239,9 @@ static int sx8654_probe(struct i2c_client *client, 


	input_set_drvdata(sx8654->input, sx8654);



	error = i2c_smbus_write_byte_data(client, I2C_REG_SOFTRESET,

					  SOFTRESET_VALUE);

	error = sx8654_reset(sx8654);

	if (error) {

		dev_err(&client->dev, "writing softreset value failed");

		dev_err(&client->dev, "reset failed");

		return error;

	}

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