Re: [PATCH v9 1/4] dt-bindings: display: xlnx: Add ZynqMP DP subsystem bindings

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

Hi Rob,

On Thu, Sep 26, 2019 at 09:57:29AM -0500, Rob Herring wrote:
> On Thu, Sep 26, 2019 at 9:23 AM Laurent Pinchart wrote:
> > On Thu, Sep 26, 2019 at 09:15:01AM -0500, Rob Herring wrote:
> > > On Wed, Sep 25, 2019 at 6:56 PM Laurent Pinchart wrote:
> > > >
> > > > From: Hyun Kwon <hyun.kwon@xilinx.com>
> > > >
> > > > The bindings describe the ZynqMP DP subsystem. They don't support the
> > > > interface with the programmable logic (FPGA) or audio yet.
> > > >
> > > > Signed-off-by: Hyun Kwon <hyun.kwon@xilinx.com>
> > > > Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> > > > ---
> > > > Changes since v8:
> > > >
> > > > - Convert to yaml
> > > > - Rename aclk to dp_apb_clk
> > >
> > > /builds/robherring/linux-dt-review/Documentation/devicetree/bindings/display/xlnx/xlnx,zynqmp-dpsub.example.dt.yaml:
> > > display@fd4a0000: clock-names:2: 'dp_vtc_pixel_clk_in' was expected
> >
> > If you allow me to steal a bit of your brain time, could you help me
> > expressing the clocks constraint ?
> >
> >   clocks:
> >     description:
> >       The AXI clock and at least one video clock are mandatory, the audio clock
> >       optional.
> >     minItems: 2
> >     maxItems: 4
> >     items:
> >       - description: AXI clock
> >       - description: Audio clock
> >       - description: Non-live video clock (from Processing System)
> >       - description: Live video clock (from Programmable Logic)
> >   clock-names:
> >     minItems: 2
> >     maxItems: 4
> >     items:
> >       - const: dp_apb_clk
> >       - const: dp_aud_clk
> >       - const: dp_vtc_pixel_clk_in
> >       - const: dp_live_video_in_clk
> >
> > dp_apb_clk is required, dp_aud_clk is optional, and at least one of
> > dp_vtc_pixel_clk_in and dp_live_video_in_clk is required.
> 
> I'm hoping people's inability to express the schema will prevent
> complicated ones like this in the first place...
> 
> clock-names:
>   oneOf:
>     - minItems: 3
>       maxItems: 4
>       items:
>         - const: dp_apb_clk
>         - const: dp_aud_clk
>         - enum: [ dp_vtc_pixel_clk_in, dp_live_video_in_clk ]
>         - enum: [ dp_vtc_pixel_clk_in, dp_live_video_in_clk ]
>     - minItems: 2
>       maxItems: 3
>       items:
>         - const: dp_apb_clk
>         - enum: [ dp_vtc_pixel_clk_in, dp_live_video_in_clk ]
>         - enum: [ dp_vtc_pixel_clk_in, dp_live_video_in_clk ]

The above would make

	clock-names = "dp_apb_clk", "dp_vtc_pixel_clk_in", "dp_vtc_pixel_clk_in";

valid. I've investigated a little bit and found uniqueItems which solves
my issue.

Would the following simpler solution be acceptable ?

clock-names:
    minItems: 2
    maxItems: 4
    items:
      - const: dp_apb_clk
      - enum: [ dp_vtc_pixel_clk_in, dp_live_video_in_clk ]
      - const: dp_aud_clk
      - enum: [ dp_vtc_pixel_clk_in, dp_live_video_in_clk ]
    uniqueItems: true

> Strictly speaking, that leaves items clocks wrong, but 'description'
> doesn't do anything. So I'd just leave it as is.

Speaking of which, there doesn't seem to be anything that validates the
size of clocks and clock-names being identical. Is that a known issue ?

-- 
Regards,

Laurent Pinchart