Re: [PATCH] gpio: pca953x: Add optional reset gpio control

[Steve Longerbeam]

On 01/04/2017 02:25 AM, Vladimir Zapolskiy wrote:
> Hi Steve,
>
> On 01/02/2017 11:07 PM, 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_longerbeam@xxxxxxxxxx>
> > Cc: Linus Walleij <linus.walleij@xxxxxxxxxx>
> > Cc: Alexandre Courbot <gnurou@xxxxxxxxx>
> > Cc: linux-gpio@xxxxxxxxxxxxxxx
> > Cc: linux-kernel@xxxxxxxxxxxxxxx
> > ---
> >   Documentation/devicetree/bindings/gpio/gpio-pca953x.txt |  4 ++++
> >   drivers/gpio/gpio-pca953x.c                             | 11 +++++++++++
> >   2 files changed, 15 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
> > +
> > +
> Drop the surplus empty line above.

done.

> >   Example:
> >   
> >   
> > diff --git a/drivers/gpio/gpio-pca953x.c b/drivers/gpio/gpio-pca953x.c
> > index d5d72d8..ca2ddea 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
> > @@ -754,8 +755,18 @@ static int pca953x_probe(struct i2c_client *client,
> >   		invert = pdata->invert;
> >   		chip->names = pdata->names;
> >   	} else {
> > +		struct gpio_desc *reset_gpio;
> > +
> >   		chip->gpio_start = -1;
> >   		irq_base = 0;
> > +
> > +		/* see if we need to de-assert a reset pin */
> > +		reset_gpio = devm_gpiod_get_optional(&client->dev, "reset",
> > +						     GPIOD_OUT_LOW);
> > +		if (IS_ERR(reset_gpio)) {
> > +			dev_err(&client->dev, "request for reset pin failed\n");
> I'm not confident that the error message is wanted here, you may consider either
> to remove it or at least print it out if (PTR_ERR(reset_gpio) != -EPROBE_DEFER).

no problem, I just removed it.


Steve