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Commit 12097957 authored by Laurent Pinchart's avatar Laurent Pinchart Committed by Wolfram Sang
Browse files

i2c: pca954x: Add reset GPIO support 



If a reset GPIO support is specified, request the GPIO and get the chip
out of reset at probe time.

Signed-off-by: default avatarLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: default avatarWolfram Sang <wsa@the-dreams.de>
parent 4215138e

Documentation/devicetree/bindings/i2c/i2c-mux-pca954x.txt

+4 −0
Original line number Diff line number Diff line
@@ -13,6 +13,10 @@ Required Properties: 
  - Standard I2C mux properties. See i2c-mux.txt in this directory.

  - I2C child bus nodes. See i2c-mux.txt in this directory.



Optional Properties:



  - reset-gpios: Reference to the GPIO connected to the reset input.





Example:

drivers/i2c/muxes/i2c-mux-pca954x.c

+19 −0
Original line number Diff line number Diff line
@@ -36,11 +36,13 @@ 
 */



#include <linux/device.h>

#include <linux/gpio.h>

#include <linux/i2c.h>

#include <linux/i2c-mux.h>

#include <linux/i2c/pca954x.h>

#include <linux/init.h>

#include <linux/module.h>

#include <linux/of_gpio.h>

#include <linux/slab.h>



#define PCA954X_MAX_NCHANS 8
@@ -185,6 +187,7 @@ static int pca954x_probe(struct i2c_client *client, 
{

	struct i2c_adapter *adap = to_i2c_adapter(client->dev.parent);

	struct pca954x_platform_data *pdata = dev_get_platdata(&client->dev);

	struct device_node *np = client->dev.of_node;

	int num, force, class;

	struct pca954x *data;

	int ret;
@@ -198,6 +201,22 @@ static int pca954x_probe(struct i2c_client *client, 


	i2c_set_clientdata(client, data);



	if (IS_ENABLED(CONFIG_OF) && np) {

		enum of_gpio_flags flags;

		int gpio;



		/* Get the mux out of reset if a reset GPIO is specified. */

		gpio = of_get_named_gpio_flags(np, "reset-gpio", 0, &flags);

		if (gpio_is_valid(gpio)) {

			ret = devm_gpio_request_one(&client->dev, gpio,

					flags & OF_GPIO_ACTIVE_LOW ?

					GPIOF_OUT_INIT_HIGH : GPIOF_OUT_INIT_LOW,

					"pca954x reset");

			if (ret < 0)

				return ret;

		}

	}



	/* Write the mux register at addr to verify

	 * that the mux is in fact present. This also

	 * initializes the mux to disconnected state.