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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: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
This commit is contained in:
Laurent Pinchart 2013-11-29 01:51:25 +01:00 committed by Wolfram Sang
parent 4215138e08
commit 12097957a9
2 changed files with 23 additions and 0 deletions
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4
Documentation/devicetree/bindings/i2c/i2c-mux-pca954x.txt
View File

@ -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:

19
drivers/i2c/muxes/i2c-mux-pca954x.c
View File

@ -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.