Re: [PATCH 1/5] dt-bindings: display: panel-dpi: Add bits-per-color property

From: Rob Herring <robh@kernel.org>
To: Chen-Yu Tsai <wens@kernel.org>
Cc: Maxime Ripard <mripard@kernel.org>,
	Sam Ravnborg <sam@ravnborg.org>,
	Thierry Reding <thierry.reding@gmail.com>,
	David Airlie <airlied@linux.ie>, Daniel Vetter <daniel@ffwll.ch>,
	Chen-Yu Tsai <wens@csie.org>,
	linux-arm-kernel@lists.infradead.org, devicetree@vger.kernel.org,
	dri-devel@lists.freedesktop.org,
	Siarhei Siamashka <siarhei.siamashka@gmail.com>
Subject: Re: [PATCH 1/5] dt-bindings: display: panel-dpi: Add bits-per-color property
Date: Mon, 20 Jul 2020 20:10:26 -0600	[thread overview]
Message-ID: <20200721021026.GA3382460@bogus> (raw)
In-Reply-To: <20200714071305.18492-2-wens@kernel.org>

On Tue, Jul 14, 2020 at 03:13:01PM +0800, Chen-Yu Tsai wrote:
> From: Chen-Yu Tsai <wens@csie.org>
> 
> Some LCD panels do not support 24-bit true color, or 8bits per channel
> RGB. Many low end ones only support up to 6 bits per channel natively.

This should be implied by the panel's compatible property.

> Add a device tree property to describe the native bit depth of the
> panel. This is separate from the bus width or format of the connection
> to the display output.
> 
> Signed-off-by: Chen-Yu Tsai <wens@csie.org>
> ---
>  .../devicetree/bindings/display/panel/panel-dpi.yaml          | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/display/panel/panel-dpi.yaml b/Documentation/devicetree/bindings/display/panel/panel-dpi.yaml
> index 0cd74c8dab42..8eb013fb1969 100644
> --- a/Documentation/devicetree/bindings/display/panel/panel-dpi.yaml
> +++ b/Documentation/devicetree/bindings/display/panel/panel-dpi.yaml
> @@ -26,6 +26,9 @@ properties:
>    height-mm: true
>    label: true
>    panel-timing: true
> +  bits-per-color:
> +    description:
> +      Shall contain an integer describing the number of bits per color.
>    port: true
>    power-supply: true
>    reset-gpios: true
> @@ -42,6 +45,7 @@ examples:
>      panel {
>          compatible = "osddisplays,osd057T0559-34ts", "panel-dpi";
>          label = "osddisplay";
> +        bits-per-color = <8>;
>          power-supply = <&vcc_supply>;
>          backlight = <&backlight>;
>  
> -- 
> 2.27.0
> 