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

2015-12-20 Thread Uwe Kleine-König 
[Cc += devicet...@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 
> > 
> > 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 
> > ---
> >  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 devicet...@vger.kernel.org. And, I think,
> the binding document changes are usually as a separate patch.

Right for devicet...@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(>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", );
> > 
> 
> 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/  |
--
To unsubscribe from this list: send the line "unsubscribe linux-omap" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

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

2015-12-16 Thread Tomi Valkeinen 

On 10/12/15 15:11, Uwe Kleine-König wrote:
> From: Uwe Kleine-König 
> 
> 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 
> ---
>  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 devicet...@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(>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", );
> 

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



signature.asc
Description: OpenPGP digital signature

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

2015-12-10 Thread Uwe Kleine-König 
From: Uwe Kleine-König 

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 
---
 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(>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", );
-- 
2.6.2

--
To unsubscribe from this list: send the line "unsubscribe linux-omap" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html