Re: [PATCH v8 10/14] dt-bindings: Document the Rockchip ISP1 bindings

Laurent Pinchart
2019-08-16T00:21:54Z

Hi Helen,

Thank you for the patch.

On Tue, Jul 30, 2019 at 03:42:52PM -0300, Helen Koike wrote:
> From: Jacob Chen <jacob2.chen@rock-chips.com>
>
> Add DT bindings documentation for Rockchip ISP1
>
> Signed-off-by: Jacob Chen <jacob2.chen@rock-chips.com>
> Reviewed-by: Rob Herring <robh@kernel.org>
> [update for upstream]
> Signed-off-by: Helen Koike <helen.koike@collabora.com>
>
> ---
>
> Changes in v8: None
> Changes in v7:
> - update document with new design and tested example
>
> .../bindings/media/rockchip-isp1.txt | 71 +++++++++++++++++++
> 1 file changed, 71 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/media/rockchip-isp1.txt
>
> diff --git a/Documentation/devicetree/bindings/media/rockchip-isp1.txt b/Documentation/devicetree/bindings/media/rockchip-isp1.txt
> new file mode 100644
> index 000000000000..a97fef0f189f
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/media/rockchip-isp1.txt

If there wasn't enough work on your plate already I'd propose converting
this to yaml, but I'll refrain from doing so :-)

> @@ -0,0 +1,71 @@
> +Rockchip SoC Image Signal Processing unit v1
> +----------------------------------------------
> +
> +Rockchip ISP1 is the Camera interface for the Rockchip series of SoCs
> +which contains image processing, scaling, and compression funcitons.

s/funcitons/functions/

> +
> +Required properties:
> +- compatible: value should be one of the following
> + "rockchip,rk3288-cif-isp";
> + "rockchip,rk3399-cif-isp";
> +- reg : offset and length of the register set for the device.
> +- interrupts: should contain ISP interrupt.
> +- clocks: phandle to the required clocks.
> +- clock-names: required clock name.
> +- iommus: required a iommu node.
> +- phys: the phandle for the PHY port
> +- phy-names: must contain "dphy"
> +
> +port node
> +-------------------
> +
> +The device node should contain one 'ports' child node, with children 'port'
> +with child 'endpoint'.

Extra . and line break ?

> +nodes, according to the bindings defined in Documentation/devicetree/bindings/
> +media/video-interfaces.txt.
> +
> +- endpoint(mipi):
> + - remote-endpoint: Connecting to Rockchip MIPI-DPHY,
> + which is defined in rockchip-mipi-dphy.txt.
> +
> +The port node must contain at least one endpoint, either parallel or mipi.

If I understand things correctly, each ISP has a single CSI-2 receiver
and a single parallel output, and can select one of them at runtime.
This should be modelled as two separate ports. In addition to this,
multiple CSI-2 sensors can be connected to the same CSI-2 receiver as
long as all but one of them is held in reset (this is a poor man's CSI-2
switch, which exists in device out in the market, so we have to support
that). This should be modelled by multiple endpoints in the CSI-2 port.

> +It could have multiple endpoints, but please note the hardware don't support
> +two sensors work at a time, they are supposed to work asynchronously.

I assume you meant "are supposed to be mutually exclusive" or something
similar ?

> +
> +Device node example
> +-------------------
> +
> + isp0: isp0@ff910000 {
> + compatible = "rockchip,rk3399-cif-isp";
> + reg = <0x0 0xff910000 0x0 0x4000>;
> + interrupts = <GIC_SPI 43 IRQ_TYPE_LEVEL_HIGH 0>;
> + clocks = <&cru SCLK_ISP0>,
> + <&cru ACLK_ISP0>, <&cru ACLK_ISP0_WRAPPER>,
> + <&cru HCLK_ISP0>, <&cru HCLK_ISP0_WRAPPER>;
> + clock-names = "clk_isp",
> + "aclk_isp", "aclk_isp_wrap",
> + "hclk_isp", "hclk_isp_wrap";
> + power-domains = <&power RK3399_PD_ISP0>;
> + iommus = <&isp0_mmu>;
> + phys = <&dphy>;
> + phy-names = "dphy";
> +
> + ports {
> + #address-cells = <1>;
> + #size-cells = <0>;
> +
> + port@0 {
> + mipi_in_wcam: endpoint@0 {
> + reg = <0>;
> + remote-endpoint = <&wcam_out>;
> + data-lanes = <1 2>;
> + };
> +
> + mipi_in_ucam: endpoint@1 {
> + reg = <1>;
> + remote-endpoint = <&ucam_out>;
> + data-lanes = <1>;
> + };

What are wcam and ucam ? It would help if you showed the sensor nodes in
the example.

> + };
> + };
> + };

--
Regards,

Laurent Pinchart