Hi, On Thu, 29 Dec 2016 14:27:25 -0800 Steve Longerbeam wrote: > Add optional reset-gpios pin control. If present, de-assert the > specified reset gpio pin to bring the chip out of reset. > > Signed-off-by: Steve Longerbeam <steve_longerb...@mentor.com> > Cc: Linus Walleij <linus.wall...@linaro.org> > Cc: Alexandre Courbot <gnu...@gmail.com> > Cc: linux-g...@vger.kernel.org > Cc: linux-ker...@vger.kernel.org > > --- > > v2: > - documented optional reset-gpios property in > Documentation/devicetree/bindings/gpio/gpio-pca953x.txt. > --- > Documentation/devicetree/bindings/gpio/gpio-pca953x.txt | 4 ++++ > drivers/gpio/gpio-pca953x.c | 17 > +++++++++++++++++ > 2 files changed, 21 insertions(+) > > diff --git a/Documentation/devicetree/bindings/gpio/gpio-pca953x.txt > b/Documentation/devicetree/bindings/gpio/gpio-pca953x.txt > index 08dd15f..da54f4c 100644 > --- a/Documentation/devicetree/bindings/gpio/gpio-pca953x.txt > +++ b/Documentation/devicetree/bindings/gpio/gpio-pca953x.txt > @@ -29,6 +29,10 @@ Required properties: > onsemi,pca9654 > exar,xra1202 > > +Optional properties: > + - reset-gpios: GPIO specification for the RESET input > + > + > Example: > > > diff --git a/drivers/gpio/gpio-pca953x.c b/drivers/gpio/gpio-pca953x.c > index d5d72d8..d1c0bd5 100644 > --- a/drivers/gpio/gpio-pca953x.c > +++ b/drivers/gpio/gpio-pca953x.c > @@ -22,6 +22,7 @@ > #include <linux/of_platform.h> > #include <linux/acpi.h> > #include <linux/regulator/consumer.h> > +#include <linux/gpio/consumer.h> > > #define PCA953X_INPUT 0 > #define PCA953X_OUTPUT 1 > @@ -133,6 +134,7 @@ struct pca953x_chip { > const char *const *names; > unsigned long driver_data; > struct regulator *regulator; > + struct gpio_desc *reset_gpio; > > const struct pca953x_reg_config *regs; > > @@ -756,6 +758,21 @@ static int pca953x_probe(struct i2c_client *client, > } else { > chip->gpio_start = -1; > irq_base = 0; > + > + /* see if we need to de-assert a reset pin */ > + chip->reset_gpio = devm_gpiod_get_optional(&client->dev, > + "reset", > + GPIOD_OUT_LOW);
> + if (IS_ERR(chip->reset_gpio)) { > + dev_err(&client->dev, "request for reset pin failed\n"); > + return PTR_ERR(chip->reset_gpio); > + } > + > + if (chip->reset_gpio) { > + /* bring chip out of reset */ > + dev_info(&client->dev, "releasing reset\n"); > + gpiod_set_value(chip->reset_gpio, 0); > The pin is already initialized to the inactive state thru the GPIOD_OUT_LOW flag in devm_gpiod_get_optional(), so this call to gpiod_set_value() is useless. Lothar Waßmann _______________________________________________ devel mailing list de...@linuxdriverproject.org http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel