This adds support for the optional reset gpio to the ad2s1210 resolver
driver. If the gpio is present in the device tree, it is toggled during
driver probe before the reset of the device initialization. As per the
devicetree bindings, it is expected for the gpio to configured as active
low.

Suggested-by: Michael Hennerich <Michael.Hennerich@analog.com>
Signed-off-by: David Lechner <dlechner@baylibre.com>
---
 drivers/iio/resolver/ad2s1210.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/drivers/iio/resolver/ad2s1210.c b/drivers/iio/resolver/ad2s1210.c
index 8646389ec88d..a414eef12e5e 100644
--- a/drivers/iio/resolver/ad2s1210.c
+++ b/drivers/iio/resolver/ad2s1210.c
@@ -1426,6 +1426,7 @@ static int ad2s1210_setup_gpios(struct ad2s1210_state *st)
 {
 	struct device *dev = &st->sdev->dev;
 	struct gpio_descs *resolution_gpios;
+	struct gpio_desc *reset_gpio;
 	DECLARE_BITMAP(bitmap, 2);
 	int ret;
 
@@ -1481,6 +1482,17 @@ static int ad2s1210_setup_gpios(struct ad2s1210_state *st)
 					     "failed to set resolution gpios\n");
 	}
 
+	/* If the optional reset GPIO is present, toggle it to do a hard reset. */
+	reset_gpio = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH);
+	if (IS_ERR(reset_gpio))
+		return dev_err_probe(dev, PTR_ERR(reset_gpio),
+				     "failed to request reset GPIO\n");
+
+	if (reset_gpio) {
+		udelay(10);
+		gpiod_set_value(reset_gpio, 0);
+	}
+
 	return 0;
 }
 
-- 
2.42.0

> -----Original Message-----
> From: David Lechner <dlechner@baylibre.com>
> Sent: Montag, 16. Oktober 2023 17:43
> To: linux-iio@vger.kernel.org
> Cc: David Lechner <dlechner@baylibre.com>; Jonathan Cameron
> <jic23@kernel.org>; Hennerich, Michael <Michael.Hennerich@analog.com>;
> Sa, Nuno <Nuno.Sa@analog.com>; linux-kernel@vger.kernel.org
> Subject: [PATCH] iio: resolver: ad2s1210: add reset gpio support
> 
> 
> This adds support for the optional reset gpio to the ad2s1210 resolver driver. If
> the gpio is present in the device tree, it is toggled during driver probe before the
> reset of the device initialization. As per the devicetree bindings, it is expected for
> the gpio to configured as active low.
> 
> Suggested-by: Michael Hennerich <Michael.Hennerich@analog.com>
> Signed-off-by: David Lechner <dlechner@baylibre.com>
> ---

Acked-by: Michael Hennerich <michael.hennerich@analog.com>

>  drivers/iio/resolver/ad2s1210.c | 12 ++++++++++++
>  1 file changed, 12 insertions(+)
> 
> diff --git a/drivers/iio/resolver/ad2s1210.c b/drivers/iio/resolver/ad2s1210.c
> index 8646389ec88d..a414eef12e5e 100644
> --- a/drivers/iio/resolver/ad2s1210.c
> +++ b/drivers/iio/resolver/ad2s1210.c
> @@ -1426,6 +1426,7 @@ static int ad2s1210_setup_gpios(struct
> ad2s1210_state *st)  {
>  	struct device *dev = &st->sdev->dev;
>  	struct gpio_descs *resolution_gpios;
> +	struct gpio_desc *reset_gpio;
>  	DECLARE_BITMAP(bitmap, 2);
>  	int ret;
> 
> @@ -1481,6 +1482,17 @@ static int ad2s1210_setup_gpios(struct
> ad2s1210_state *st)
>  					     "failed to set resolution gpios\n");
>  	}
> 
> +	/* If the optional reset GPIO is present, toggle it to do a hard reset. */
> +	reset_gpio = devm_gpiod_get_optional(dev, "reset",
> GPIOD_OUT_HIGH);
> +	if (IS_ERR(reset_gpio))
> +		return dev_err_probe(dev, PTR_ERR(reset_gpio),
> +				     "failed to request reset GPIO\n");
> +
> +	if (reset_gpio) {
> +		udelay(10);
> +		gpiod_set_value(reset_gpio, 0);
> +	}
> +
>  	return 0;
>  }
> 
> --
> 2.42.0

On Tue, 17 Oct 2023 13:46:51 +0000
"Hennerich, Michael" <Michael.Hennerich@analog.com> wrote:

> > -----Original Message-----
> > From: David Lechner <dlechner@baylibre.com>
> > Sent: Montag, 16. Oktober 2023 17:43
> > To: linux-iio@vger.kernel.org
> > Cc: David Lechner <dlechner@baylibre.com>; Jonathan Cameron
> > <jic23@kernel.org>; Hennerich, Michael <Michael.Hennerich@analog.com>;
> > Sa, Nuno <Nuno.Sa@analog.com>; linux-kernel@vger.kernel.org
> > Subject: [PATCH] iio: resolver: ad2s1210: add reset gpio support
> > 
> > 
> > This adds support for the optional reset gpio to the ad2s1210 resolver driver. If
> > the gpio is present in the device tree, it is toggled during driver probe before the
> > reset of the device initialization. As per the devicetree bindings, it is expected for
> > the gpio to configured as active low.
> > 
> > Suggested-by: Michael Hennerich <Michael.Hennerich@analog.com>
> > Signed-off-by: David Lechner <dlechner@baylibre.com>
> > ---  
> 
> Acked-by: Michael Hennerich <michael.hennerich@analog.com>
Applied and pushed out as testing for 0-day to poke at it.

Thanks,

Jonathan

> 
> >  drivers/iio/resolver/ad2s1210.c | 12 ++++++++++++
> >  1 file changed, 12 insertions(+)
> > 
> > diff --git a/drivers/iio/resolver/ad2s1210.c b/drivers/iio/resolver/ad2s1210.c
> > index 8646389ec88d..a414eef12e5e 100644
> > --- a/drivers/iio/resolver/ad2s1210.c
> > +++ b/drivers/iio/resolver/ad2s1210.c
> > @@ -1426,6 +1426,7 @@ static int ad2s1210_setup_gpios(struct
> > ad2s1210_state *st)  {
> >  	struct device *dev = &st->sdev->dev;
> >  	struct gpio_descs *resolution_gpios;
> > +	struct gpio_desc *reset_gpio;
> >  	DECLARE_BITMAP(bitmap, 2);
> >  	int ret;
> > 
> > @@ -1481,6 +1482,17 @@ static int ad2s1210_setup_gpios(struct
> > ad2s1210_state *st)
> >  					     "failed to set resolution gpios\n");
> >  	}
> > 
> > +	/* If the optional reset GPIO is present, toggle it to do a hard reset. */
> > +	reset_gpio = devm_gpiod_get_optional(dev, "reset",
> > GPIOD_OUT_HIGH);
> > +	if (IS_ERR(reset_gpio))
> > +		return dev_err_probe(dev, PTR_ERR(reset_gpio),
> > +				     "failed to request reset GPIO\n");
> > +
> > +	if (reset_gpio) {
> > +		udelay(10);
> > +		gpiod_set_value(reset_gpio, 0);
> > +	}
> > +
> >  	return 0;
> >  }
> > 
> > --
> > 2.42.0  
>