Re: [PATCH v1 1/7] dt-bindings: display: add STM32 LTDC driver

From: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
To: dri-devel@lists.freedesktop.org
Cc: Mark Rutland <mark.rutland@arm.com>,
	devicetree@vger.kernel.org,
	Alexandre TORGUE <alexandre.torgue@st.com>,
	Arnd Bergmann <arnd@arndb.de>,
	Russell King <linux@armlinux.org.uk>,
	Rob Herring <robh+dt@kernel.org>,
	Philippe Cornu <philippe.cornu@st.com>,
	Yannick Fertre <yannick.fertre@st.com>,
	Maxime Coquelin <mcoquelin.stm32@gmail.com>,
	Mickael Reulier <mickael.reulier@st.com>,
	Gabriel FERNANDEZ <gabriel.fernandez@st.com>,
	linux-arm-kernel@lists.infradead.org, kernel@stlinux.com
Subject: Re: [PATCH v1 1/7] dt-bindings: display: add STM32 LTDC driver
Date: Mon, 16 Jan 2017 22:30:49 +0200	[thread overview]
Message-ID: <2080174.sm3cyM9MmB@avalon> (raw)
In-Reply-To: <1484573344-11609-2-git-send-email-yannick.fertre@st.com>

Hi Yannick,

Thank you for the patch.

On Monday 16 Jan 2017 14:28:58 Yannick Fertre wrote:
> Signed-off-by: Yannick Fertre <yannick.fertre@st.com>
> ---
>  .../devicetree/bindings/display/st,ltdc.txt        | 57 ++++++++++++++++++
>  1 file changed, 57 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/display/st,ltdc.txt
> 
> diff --git a/Documentation/devicetree/bindings/display/st,ltdc.txt
> b/Documentation/devicetree/bindings/display/st,ltdc.txt new file mode
> 100644
> index 0000000..20e89da
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/display/st,ltdc.txt
> @@ -0,0 +1,57 @@
> +* STMicroelectronics STM32 lcd-tft display controller
> +
> +- st-display-subsystem: Master device for DRM sub-components
> +  This device must be the parent of all the sub-components and is
> responsible
> +  of bind them.

Why do you need this ? At a quick glance the ltdc node should be enough.

> +  Required properties:
> +  - compatible: "st,display-subsystem"
> +  - ranges: to allow probing of subdevices
> +
> +- ltdc_host: lcd-tft display controller host
> +  must be a sub-node of st-display-subsystem
> +  Required properties:
> +  - compatible: "st,ltdc"
> +  - reg: Physical base address of the IP registers and length of memory
> mapped region.
> +  - clocks: from common clock binding: handle hardware IP needed clocks,
> the
> +    number of clocks may depend of the SoC type.
> +    See ../clocks/clock-bindings.txt for details.
> +  - clock-names: names of the clocks listed in clocks property in the same
> +    order.

You need to define the required/optional clocks with their names here. If they 
vary depending on the SoC, the DT bindings document need to list them for each 
SoC.

> +  - resets: resets to be used by the device
> +    See ../reset/reset.txt for details.
> +  - reset-names: names of the resets listed in resets property in the same
> +    order.
> +  Required nodes:
> +    - Video port for RGB output.
> +
> +Example:
> +
> +/ {
> +	...
> +	soc {
> +	...
> +		st-display-subsystem {
> +			compatible = "st,display-subsystem";
> +			#address-cells = <1>;
> +			#size-cells = <1>;
> +			ranges;
> +			dma-ranges;
> +
> +			ltdc_host: stm32-ltdc@40016800 {
> +				compatible = "st,ltdc";
> +				reg = <0x40016800 0x200>;
> +				interrupts = <88>, <89>;
> +				resets = <&rcc 314>;
> +				clocks = <&rcc 1 8>;
> +				clock-names = "clk-lcd";
> +				status = "disabled";
> +
> +				port {
> +					ltdc_out_rgb: endpoint {
> +					};
> +				};
> +			};
> +		};
> +	...
> +	};
> +};

-- 
Regards,

Laurent Pinchart

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