[PATCH 1/5] fbdev: omap2: panel-dpi: in .disable first disable backlight then display

[PATCH 1/5] fbdev: omap2: panel-dpi: in .disable first disable backlight then display

[Uwe Kleine-König]

From: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>

This makes .disable operate in reverse order compared to .enable.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
---
 drivers/video/fbdev/omap2/displays-new/panel-dpi.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/video/fbdev/omap2/displays-new/panel-dpi.c b/drivers/video/fbdev/omap2/displays-new/panel-dpi.c
index f7be3489f744..06b6e611e4b2 100644
--- a/drivers/video/fbdev/omap2/displays-new/panel-dpi.c
+++ b/drivers/video/fbdev/omap2/displays-new/panel-dpi.c
@@ -102,12 +102,12 @@ static void panel_dpi_disable(struct omap_dss_device *dssdev)
 	if (!omapdss_device_is_enabled(dssdev))
 		return;
 
-	if (ddata->enable_gpio)
-		gpiod_set_value_cansleep(ddata->enable_gpio, 0);
-
 	if (gpio_is_valid(ddata->backlight_gpio))
 		gpio_set_value_cansleep(ddata->backlight_gpio, 0);
 
+	if (ddata->enable_gpio)
+		gpiod_set_value_cansleep(ddata->enable_gpio, 0);
+
 	in->ops.dpi->disable(in);
 
 	dssdev->state = OMAP_DSS_DISPLAY_DISABLED;
-- 
2.6.2

[PATCH 4/5] fbdev: omap2: panel-dpi: allow specification of a reset gpio

[Uwe Kleine-König]

From: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>

Some displays have a reset input. To assert that the display is
functional the reset gpio must be deasserted.

Teach the driver to get and drive such a gpio accordingly.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
---
 Documentation/devicetree/bindings/video/panel-dpi.txt | 1 +
 drivers/video/fbdev/omap2/displays-new/panel-dpi.c    | 7 +++++++
 2 files changed, 8 insertions(+)

diff --git a/Documentation/devicetree/bindings/video/panel-dpi.txt b/Documentation/devicetree/bindings/video/panel-dpi.txt
index a40180b05bab..1a1d8f6f884f 100644
--- a/Documentation/devicetree/bindings/video/panel-dpi.txt
+++ b/Documentation/devicetree/bindings/video/panel-dpi.txt
@@ -7,6 +7,7 @@ Required properties:
 Optional properties:
 - label: a symbolic name for the panel
 - enable-gpios: panel enable gpio
+- reset-gpios: GPIO to control the RESET pin
 
 Required nodes:
 - "panel-timing" containing video timings
diff --git a/drivers/video/fbdev/omap2/displays-new/panel-dpi.c b/drivers/video/fbdev/omap2/displays-new/panel-dpi.c
index 1216341a0d19..7e2f9e0813dc 100644
--- a/drivers/video/fbdev/omap2/displays-new/panel-dpi.c
+++ b/drivers/video/fbdev/omap2/displays-new/panel-dpi.c
@@ -32,6 +32,7 @@ struct panel_drv_data {
 	int backlight_gpio;
 
 	struct gpio_desc *enable_gpio;
+	struct gpio_desc *reset_gpio;
 };
 
 #define to_panel_data(p) container_of(p, struct panel_drv_data, dssdev)
@@ -83,6 +84,7 @@ static int panel_dpi_enable(struct omap_dss_device *dssdev)
 	if (r)
 		return r;
 
+	gpiod_set_value_cansleep(ddata->reset_gpio, 0);
 	gpiod_set_value_cansleep(ddata->enable_gpio, 1);
 
 	if (gpio_is_valid(ddata->backlight_gpio))
@@ -211,6 +213,11 @@ static int panel_dpi_probe_of(struct platform_device *pdev)
 	if (IS_ERR(ddata->enable_gpio))
 		return PTR_ERR(ddata->enable_gpio);
 
+	ddata->reset_gpio = devm_gpiod_get_optional(&pdev->dev,
+						    "reset", GPIOD_OUT_HIGH);
+	if (IS_ERR(ddata->reset_gpio))
+		return PTR_ERR(ddata->reset_gpio);
+
 	ddata->backlight_gpio = -ENOENT;
 
 	r = of_get_display_timing(node, "panel-timing", &timing);
-- 
2.6.2

Re: [PATCH 4/5] fbdev: omap2: panel-dpi: allow specification of a reset gpio

[Tomi Valkeinen]

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On 10/12/15 15:11, Uwe Kleine-König wrote:
> From: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
> 
> Some displays have a reset input. To assert that the display is
> functional the reset gpio must be deasserted.
> 
> Teach the driver to get and drive such a gpio accordingly.
> 
> Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
> ---
>  Documentation/devicetree/bindings/video/panel-dpi.txt | 1 +
>  drivers/video/fbdev/omap2/displays-new/panel-dpi.c    | 7 +++++++
>  2 files changed, 8 insertions(+)

DT changes should be posted to devicetree@vger.kernel.org. And, I think,
the binding document changes are usually as a separate patch.

> diff --git a/Documentation/devicetree/bindings/video/panel-dpi.txt b/Documentation/devicetree/bindings/video/panel-dpi.txt
> index a40180b05bab..1a1d8f6f884f 100644
> --- a/Documentation/devicetree/bindings/video/panel-dpi.txt
> +++ b/Documentation/devicetree/bindings/video/panel-dpi.txt
> @@ -7,6 +7,7 @@ Required properties:
>  Optional properties:
>  - label: a symbolic name for the panel
>  - enable-gpios: panel enable gpio
> +- reset-gpios: GPIO to control the RESET pin
>  
>  Required nodes:
>  - "panel-timing" containing video timings
> diff --git a/drivers/video/fbdev/omap2/displays-new/panel-dpi.c b/drivers/video/fbdev/omap2/displays-new/panel-dpi.c
> index 1216341a0d19..7e2f9e0813dc 100644
> --- a/drivers/video/fbdev/omap2/displays-new/panel-dpi.c
> +++ b/drivers/video/fbdev/omap2/displays-new/panel-dpi.c
> @@ -32,6 +32,7 @@ struct panel_drv_data {
>  	int backlight_gpio;
>  
>  	struct gpio_desc *enable_gpio;
> +	struct gpio_desc *reset_gpio;
>  };
>  
>  #define to_panel_data(p) container_of(p, struct panel_drv_data, dssdev)
> @@ -83,6 +84,7 @@ static int panel_dpi_enable(struct omap_dss_device *dssdev)
>  	if (r)
>  		return r;
>  
> +	gpiod_set_value_cansleep(ddata->reset_gpio, 0);
>  	gpiod_set_value_cansleep(ddata->enable_gpio, 1);
>  
>  	if (gpio_is_valid(ddata->backlight_gpio))
> @@ -211,6 +213,11 @@ static int panel_dpi_probe_of(struct platform_device *pdev)
>  	if (IS_ERR(ddata->enable_gpio))
>  		return PTR_ERR(ddata->enable_gpio);
>  
> +	ddata->reset_gpio = devm_gpiod_get_optional(&pdev->dev,
> +						    "reset", GPIOD_OUT_HIGH);
> +	if (IS_ERR(ddata->reset_gpio))
> +		return PTR_ERR(ddata->reset_gpio);
> +
>  	ddata->backlight_gpio = -ENOENT;
>  
>  	r = of_get_display_timing(node, "panel-timing", &timing);
> 

This looks a bit odd to me. This only ever sets the reset gpio to 0, on
panel enable. If we never toggle the reset, it could be set to 0 at
probe time, right?

Reset is a bit tricky. I've seen panels where you have to have only a
short reset pulse (reset high, wait a short time, reset low). If you
leave the reset high, the panel draws extra power.

So I think the best we can do in a generic way is just to ensure the
reset is not asserted.

 Tomi


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Re: [PATCH 4/5] fbdev: omap2: panel-dpi: allow specification of a reset gpio

[Uwe Kleine-König]

[Cc += devicetree@vger.kernel.org]

Hello Tomi,

On Wed, Dec 16, 2015 at 07:35:30PM +0200, Tomi Valkeinen wrote:
> 
> On 10/12/15 15:11, Uwe Kleine-König wrote:
> > From: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
> > 
> > Some displays have a reset input. To assert that the display is
> > functional the reset gpio must be deasserted.
> > 
> > Teach the driver to get and drive such a gpio accordingly.
> > 
> > Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
> > ---
> >  Documentation/devicetree/bindings/video/panel-dpi.txt | 1 +
> >  drivers/video/fbdev/omap2/displays-new/panel-dpi.c    | 7 +++++++
> >  2 files changed, 8 insertions(+)
> 
> DT changes should be posted to devicetree@vger.kernel.org. And, I think,
> the binding document changes are usually as a separate patch.

Right for devicetree@vger.kernel.org, but separate patches for bindings
is news to me. Anyhow, I can split this off if you prefer.

> > diff --git a/Documentation/devicetree/bindings/video/panel-dpi.txt b/Documentation/devicetree/bindings/video/panel-dpi.txt
> > index a40180b05bab..1a1d8f6f884f 100644
> > --- a/Documentation/devicetree/bindings/video/panel-dpi.txt
> > +++ b/Documentation/devicetree/bindings/video/panel-dpi.txt
> > @@ -7,6 +7,7 @@ Required properties:
> >  Optional properties:
> >  - label: a symbolic name for the panel
> >  - enable-gpios: panel enable gpio
> > +- reset-gpios: GPIO to control the RESET pin
> >  
> >  Required nodes:
> >  - "panel-timing" containing video timings
> > diff --git a/drivers/video/fbdev/omap2/displays-new/panel-dpi.c b/drivers/video/fbdev/omap2/displays-new/panel-dpi.c
> > index 1216341a0d19..7e2f9e0813dc 100644
> > --- a/drivers/video/fbdev/omap2/displays-new/panel-dpi.c
> > +++ b/drivers/video/fbdev/omap2/displays-new/panel-dpi.c
> > @@ -32,6 +32,7 @@ struct panel_drv_data {
> >  	int backlight_gpio;
> >  
> >  	struct gpio_desc *enable_gpio;
> > +	struct gpio_desc *reset_gpio;
> >  };
> >  
> >  #define to_panel_data(p) container_of(p, struct panel_drv_data, dssdev)
> > @@ -83,6 +84,7 @@ static int panel_dpi_enable(struct omap_dss_device *dssdev)
> >  	if (r)
> >  		return r;
> >  
> > +	gpiod_set_value_cansleep(ddata->reset_gpio, 0);
> >  	gpiod_set_value_cansleep(ddata->enable_gpio, 1);
> >  
> >  	if (gpio_is_valid(ddata->backlight_gpio))
> > @@ -211,6 +213,11 @@ static int panel_dpi_probe_of(struct platform_device *pdev)
> >  	if (IS_ERR(ddata->enable_gpio))
> >  		return PTR_ERR(ddata->enable_gpio);
> >  
> > +	ddata->reset_gpio = devm_gpiod_get_optional(&pdev->dev,
> > +						    "reset", GPIOD_OUT_HIGH);
> > +	if (IS_ERR(ddata->reset_gpio))
> > +		return PTR_ERR(ddata->reset_gpio);
> > +
> >  	ddata->backlight_gpio = -ENOENT;
> >  
> >  	r = of_get_display_timing(node, "panel-timing", &timing);
> > 
> 
> This looks a bit odd to me. This only ever sets the reset gpio to 0, on
> panel enable. If we never toggle the reset, it could be set to 0 at
> probe time, right?
> 
> Reset is a bit tricky. I've seen panels where you have to have only a
> short reset pulse (reset high, wait a short time, reset low). If you
> leave the reset high, the panel draws extra power.
> 
> So I think the best we can do in a generic way is just to ensure the
> reset is not asserted.

Good idea, will implement this in v2.

Best regards
Uwe

-- 
Pengutronix e.K.                           | Uwe Kleine-König            |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |

Re: [PATCH 1/5] fbdev: omap2: panel-dpi: in .disable first disable backlight then display

[Tomi Valkeinen]

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On 10/12/15 15:11, Uwe Kleine-König wrote:
> From: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
> 
> This makes .disable operate in reverse order compared to .enable.
> 
> Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
> ---
>  drivers/video/fbdev/omap2/displays-new/panel-dpi.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/video/fbdev/omap2/displays-new/panel-dpi.c b/drivers/video/fbdev/omap2/displays-new/panel-dpi.c
> index f7be3489f744..06b6e611e4b2 100644
> --- a/drivers/video/fbdev/omap2/displays-new/panel-dpi.c
> +++ b/drivers/video/fbdev/omap2/displays-new/panel-dpi.c
> @@ -102,12 +102,12 @@ static void panel_dpi_disable(struct omap_dss_device *dssdev)
>  	if (!omapdss_device_is_enabled(dssdev))
>  		return;
>  
> -	if (ddata->enable_gpio)
> -		gpiod_set_value_cansleep(ddata->enable_gpio, 0);
> -
>  	if (gpio_is_valid(ddata->backlight_gpio))
>  		gpio_set_value_cansleep(ddata->backlight_gpio, 0);
>  
> +	if (ddata->enable_gpio)
> +		gpiod_set_value_cansleep(ddata->enable_gpio, 0);
> +
>  	in->ops.dpi->disable(in);
>  
>  	dssdev->state = OMAP_DSS_DISPLAY_DISABLED;
> 

Thanks, queued for 4.5.

 Tomi


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