On Wed, May 18, 2016 at 03:46:29PM +0800, Songjun Wu wrote:
> DT binding documentation for ISC driver.
>
> Signed-off-by: Songjun Wu <songjun...@atmel.com>
> ---
>
> 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 | 100
> +++++++++++++++++++++
> 1 file changed, 100 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..9e65395
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/media/atmel-isc.txt
> @@ -0,0 +1,100 @@
> +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 ISC;
> +- 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.
> +- clk-in-isc
> + ISC internal clock node, it includes two clock nodes,
> + isc-ispck and isc-mck.
And you need to describe each of these nodes and the properties they
have. But more on this below...
> +- atmel,sensor-preferred
> + ISC may convert the raw format to the specified format when the sensor
> + outputs the raw format, and the sensor may output the specified format
> + directly. If sensor is preferred to output the specified format
> + directly, the value should be 1 (1-preferred, 0-not).
> + The default value is 1.
I don't think this belongs in DT. It sounds more like a configuration
and userspace decision. It is still not clear what you mean by
"specified format".
> +
> +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.
> +
> +Required properties for the ISC internal clocks:
> +- #address-cells
> + should be 1 (reg is used to encode clk id).
> +- #size-cells
> + should be 0 (reg is used to encode clk id).
> +- name
> + device tree node describing a ISC internal clock.
> + * #clock-cells: from common clock binding; should be set to 0.
> + * reg: clock id, there are two values,
> + <0> is ISP clock, <1> is master clock.
> + * clocks: shall be the isc internal clock source phandles.
> + e.g. clocks = <&isc_clk>, <&iscck>, <&isc_gclk>;
> +
> +Example:
> +isc: isc@f0008000 {
> + compatible = "atmel,sama5d2-isc";
> + reg = <0xf0008000 0x4000>;
> + interrupts = <46 IRQ_TYPE_LEVEL_HIGH 5>;
> + clocks = <&isc_clk>, <&isc_ispck>;
> + clock-names = "hclock", "ispck";
> + atmel,sensor-preferred = <1>;
> +
> + port {
> + #address-cells = <1>;
> + #size-cells = <0>;
> +
> + isc_0: endpoint {
> + remote-endpoint = <&ov7740_0>;
> + hsync-active = <1>;
> + vsync-active = <0>;
> + pclk-sample = <1>;
> + };
> + };
> +
> + clk-in-isc {
Is this really separate from the rest of the isc block. It would be
much more simple to define all the input clocks at the parent and then
reference these 2 clocks with <&isc 0> and <&isc 1>.
> + #address-cells = <1>;
> + #size-cells = <0>;
> +
> + isc_ispck: isc-ispck@0 {
These would need a compatible string otherwise.
> + #clock-cells = <0>;
> + reg = <0>;
Are 0 and 1 meaningful in terms of the hardware description?
> + clocks = <&isc_clk>, <&iscck>;
> + };
> +
> + isc_mck: isc-mck@1 {
> + #clock-cells = <0>;
> + reg = <1>;
> + clocks = <&isc_clk>, <&iscck>, <&isc_gclk>;
> + };
> + };
> +};
