On Thu, Oct 20, 2016 at 11:43:37AM +0800, Chen-Yu Tsai wrote:
> Some rgb-to-vga bridges have an enable GPIO, either directly tied to
> an enable pin on the bridge IC, or indirectly controlling a power
> switch.
>
> Add support for it.
>
> Signed-off-by: Chen-Yu Tsai <wens@xxxxxxxx>
> ---
> .../bindings/display/bridge/dumb-vga-dac.txt | 2 ++
> drivers/gpu/drm/bridge/dumb-vga-dac.c | 28 ++++++++++++++++++++++
> 2 files changed, 30 insertions(+)
>
> diff --git a/Documentation/devicetree/bindings/display/bridge/dumb-vga-dac.txt b/Documentation/devicetree/bindings/display/bridge/dumb-vga-dac.txt
> index 003bc246a270..d3484822bf77 100644
> --- a/Documentation/devicetree/bindings/display/bridge/dumb-vga-dac.txt
> +++ b/Documentation/devicetree/bindings/display/bridge/dumb-vga-dac.txt
> @@ -16,6 +16,8 @@ graph bindings specified in Documentation/devicetree/bindings/graph.txt.
> - Video port 0 for RGB input
> - Video port 1 for VGA output
>
> +Optional properties:
> +- enable-gpios: GPIO pin to enable or disable the bridge
This should also define the active state.
> +static void dumb_vga_enable(struct drm_bridge *bridge)
> +{
> + struct dumb_vga *vga = drm_bridge_to_dumb_vga(bridge);
> +
> + if (vga->enable_gpio)
> + gpiod_set_value_cansleep(vga->enable_gpio, 1);
So the driver should allow either active high or low.
> +}
> +
> +static void dumb_vga_disable(struct drm_bridge *bridge)
> +{
> + struct dumb_vga *vga = drm_bridge_to_dumb_vga(bridge);
> +
> + if (vga->enable_gpio)
> + gpiod_set_value_cansleep(vga->enable_gpio, 0);
> +}
> +
--
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