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i2c: mux: pca954x: force reset on probe if available 

Instead of just hogging the reset GPIO into deactivated state, activate and
then de-activate the reset. This allows for better recovery if the CPU was
reset halfway through an I2C transaction for example.

Signed-off-by: Mike Looijmans <mike.looijmans@topic.nl>
Signed-off-by: Peter Rosin <peda@axentia.se>
This commit is contained in:
Mike Looijmans 2018-05-01 13:42:12 +02:00 committed by Peter Rosin
parent fca700d6d2
commit a2f8445d4c
1 changed files with 9 additions and 2 deletions
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11
drivers/i2c/muxes/i2c-mux-pca954x.c
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@ -36,6 +36,7 @@
*/
#include <linux/device.h>
#include <linux/delay.h>
#include <linux/gpio/consumer.h>
#include <linux/i2c.h>
#include <linux/i2c-mux.h>
@ -389,10 +390,16 @@ static int pca954x_probe(struct i2c_client *client,
i2c_set_clientdata(client, muxc);
data->client = client;
/* Get the mux out of reset if a reset GPIO is specified. */
gpio = devm_gpiod_get_optional(&client->dev, "reset", GPIOD_OUT_LOW);
/* Reset the mux if a reset GPIO is specified. */
gpio = devm_gpiod_get_optional(&client->dev, "reset", GPIOD_OUT_HIGH);
if (IS_ERR(gpio))
return PTR_ERR(gpio);
if (gpio) {
udelay(1);
gpiod_set_value_cansleep(gpio, 0);
/* Give the chip some time to recover. */
udelay(1);
}
match = of_match_device(of_match_ptr(pca954x_of_match), &client->dev);
if (match)