linux-kernel - Re: [PATCH v3 2/2] [media] atmel-isc: DT binding for Image Sensor Controller driver

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Message-ID: <20160602231609.GA24529@rob-hp-laptop>
Date:	Thu, 2 Jun 2016 18:16:09 -0500
From:	Rob Herring <robh@...nel.org>
To:	Songjun Wu <songjun.wu@...el.com>
Cc:	g.liakhovetski@....de, laurent.pinchart@...asonboard.com,
	nicolas.ferre@...el.com, linux-arm-kernel@...ts.infradead.org,
	devicetree@...r.kernel.org, Kumar Gala <galak@...eaurora.org>,
	linux-kernel@...r.kernel.org,
	Ian Campbell <ijc+devicetree@...lion.org.uk>,
	Pawel Moll <pawel.moll@....com>,
	Mark Rutland <mark.rutland@....com>
Subject: Re: [PATCH v3 2/2] [media] atmel-isc: DT binding for Image Sensor
 Controller driver

On Tue, May 31, 2016 at 02:58:23PM +0800, Songjun Wu wrote:
> DT binding documentation for ISC driver.
> 
> Signed-off-by: Songjun Wu <songjun.wu@...el.com>
> ---
> 
> Changes in v3:
> - Remove the 'atmel,sensor-preferred'.
> - Modify the isc clock node according to the Rob's remarks.
> 
> Changes in v2:
> - Remove the unit address of the endpoint.
> - Add the unit address to the clock node.
> - Avoid using underscores in node names.
> - Drop the "0x" in the unit address of the i2c node.
> - Modify the description of 'atmel,sensor-preferred'.
> - Add the description for the ISC internal clock.
> 
>  .../devicetree/bindings/media/atmel-isc.txt        | 88 ++++++++++++++++++++++
>  1 file changed, 88 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/media/atmel-isc.txt
> 
> diff --git a/Documentation/devicetree/bindings/media/atmel-isc.txt b/Documentation/devicetree/bindings/media/atmel-isc.txt
> new file mode 100644
> index 0000000..2ae1d60
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/media/atmel-isc.txt
> @@ -0,0 +1,88 @@
> +Atmel Image Sensor Controller (ISC)
> +----------------------------------------------
> +
> +Required properties for ISC:
> +- compatible
> +	Must be "atmel,sama5d2-isc"
> +- reg
> +	Physical base address and length of the registers set for the device;
> +- interrupts
> +	Should contain IRQ line for the ISI;
> +- clocks
> +	List of clock specifiers, corresponding to entries in
> +	the clock-names property;
> +	Please refer to clock-bindings.txt.
> +- clock-names
> +	Required elements: "hclock", "ispck".
> +- pinctrl-names, pinctrl-0
> +	Please refer to pinctrl-bindings.txt.
> +- isc-ispck
> +	The clock for the ISC digital pipeline.
> +	- compatible
> +		Must be "atmel,sama5d2-isc-ispck".
> +	- clock-cells
> +		From common clock binding; should be set to 0.
> +	- clocks
> +		The clock source phandles.
> +- isc-mck
> +	The clock for the image sensor.
> +	- compatible
> +		Must be "atmel,sama5d2-isc-mck".
> +	- clock-cells
> +		From common clock binding; should be set to 0.
> +	- clocks
> +		The clock source phandles.
> +
> +ISC supports a single port node with parallel bus. It should contain one
> +'port' child node with child 'endpoint' node. Please refer to the bindings
> +defined in Documentation/devicetree/bindings/media/video-interfaces.txt.
> +
> +Example:
> +isc: isc@...08000 {
> +	compatible = "atmel,sama5d2-isc";
> +	reg = <0xf0008000 0x4000>;
> +	interrupts = <46 IRQ_TYPE_LEVEL_HIGH 5>;
> +	clocks = <&isc_clk>, <&isc_ispck>;
> +	clock-names = "hclock", "ispck";
> +
> +	port {
> +		#address-cells = <1>;
> +		#size-cells = <0>;
> +
> +		isc_0: endpoint {
> +			remote-endpoint = <&ov7740_0>;
> +			hsync-active = <1>;
> +			vsync-active = <0>;
> +			pclk-sample = <1>;
> +		};
> +	};
> +
> +	isc_ispck: isc-ispck@0 {

Drop the unit-address. You should only have one if you have a reg 
property.

> +		compatible = "atmel,sama5d2-isc-ispck";
> +		#clock-cells = <0>;
> +		clocks = <&isc_clk>, <&iscck>;
> +	};
> +
> +	isc_mck: isc-mck@1 {

ditto.

I still think these should be implied by atmel,sama5d2-isc and not in 
DT. The fact that you don't have any registers for them pretty much 
indicates that. It is also strange that isc-ispck is used by isc. If 
that is the only user, there is certainly no need to put it in DT.


> +		compatible = "atmel,sama5d2-isc-mck";
> +		#clock-cells = <0>;
> +		clocks = <&isc_clk>, <&iscck>, <&isc_gclk>;
> +	};
> +};
> +
> +i2c1: i2c@...28000 {
> +	ov7740: camera@21 {
> +	compatible = "ovti,ov7740";
> +	reg = <0x21>;
> +
> +	clocks = <&isc_mck>;
> +	clock-names = "xvclk";
> +	assigned-clocks = <&isc_mck>;
> +	assigned-clock-rates = <24000000>;
> +
> +	port {
> +		ov7740_0: endpoint {
> +			remote-endpoint = <&isc_0>;
> +		};
> +	};
> +};
> -- 
> 2.7.4
>