| Message ID | 1449753107-11410-4-git-send-email-uwe@kleine-koenig.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
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
[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
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);