Re: [PATCH/RFC 4/6] dt-bindings: display: rockchip: dw-hdmi: Convert binding to YAML

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

Hi Maxime,

On Tue, Apr 07, 2020 at 09:12:51AM +0200, Maxime Ripard wrote:
> On Mon, Apr 06, 2020 at 08:50:28PM +0300, Laurent Pinchart wrote:
> > On Mon, Apr 06, 2020 at 07:09:15PM +0200, Maxime Ripard wrote:
> > > On Mon, Apr 06, 2020 at 02:19:27PM +0300, Laurent Pinchart wrote:
> > > > On Mon, Apr 06, 2020 at 10:00:32AM +0200, Maxime Ripard wrote:
> > > > > On Mon, Apr 06, 2020 at 02:39:33AM +0300, Laurent Pinchart wrote:
> > > > > > Convert the Rockchip HDMI TX text binding to YAML.
> > > > > >
> > > > > > Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
> > > > > > ---
> > > > > >  .../display/rockchip/dw_hdmi-rockchip.txt     |  74 --------
> > > > > >  .../display/rockchip/rockchip,dw-hdmi.yaml    | 178 ++++++++++++++++++
> > > > > >  2 files changed, 178 insertions(+), 74 deletions(-)
> > > > > >  delete mode 100644 Documentation/devicetree/bindings/display/rockchip/dw_hdmi-rockchip.txt
> > > > > >  create mode 100644 Documentation/devicetree/bindings/display/rockchip/rockchip,dw-hdmi.yaml
> > > > > >
> > > > > > diff --git a/Documentation/devicetree/bindings/display/rockchip/dw_hdmi-rockchip.txt b/Documentation/devicetree/bindings/display/rockchip/dw_hdmi-rockchip.txt
> > > > > > deleted file mode 100644
> > > > > > index 3d32ce137e7f..000000000000
> > > > > > --- a/Documentation/devicetree/bindings/display/rockchip/dw_hdmi-rockchip.txt
> > > > > > +++ /dev/null
> > > > > > @@ -1,74 +0,0 @@
> > > > > > -Rockchip DWC HDMI TX Encoder
> > > > > > -============================
> > > > > > -
> > > > > > -The HDMI transmitter is a Synopsys DesignWare HDMI 1.4 TX controller IP
> > > > > > -with a companion PHY IP.
> > > > > > -
> > > > > > -These DT bindings follow the Synopsys DWC HDMI TX bindings defined in
> > > > > > -Documentation/devicetree/bindings/display/bridge/dw_hdmi.txt with the
> > > > > > -following device-specific properties.
> > > > > > -
> > > > > > -
> > > > > > -Required properties:
> > > > > > -
> > > > > > -- compatible: should be one of the following:
> > > > > > -		"rockchip,rk3228-dw-hdmi"
> > > > > > -		"rockchip,rk3288-dw-hdmi"
> > > > > > -		"rockchip,rk3328-dw-hdmi"
> > > > > > -		"rockchip,rk3399-dw-hdmi"
> > > > > > -- reg: See dw_hdmi.txt.
> > > > > > -- reg-io-width: See dw_hdmi.txt. Shall be 4.
> > > > > > -- interrupts: HDMI interrupt number
> > > > > > -- clocks: See dw_hdmi.txt.
> > > > > > -- clock-names: Shall contain "iahb" and "isfr" as defined in dw_hdmi.txt.
> > > > > > -- ports: See dw_hdmi.txt. The DWC HDMI shall have a single port numbered 0
> > > > > > -  corresponding to the video input of the controller. The port shall have two
> > > > > > -  endpoints, numbered 0 and 1, connected respectively to the vopb and vopl.
> > > > > > -- rockchip,grf: Shall reference the GRF to mux vopl/vopb.
> > > > > > -
> > > > > > -Optional properties
> > > > > > -
> > > > > > -- ddc-i2c-bus: The HDMI DDC bus can be connected to either a system I2C master
> > > > > > -  or the functionally-reduced I2C master contained in the DWC HDMI. When
> > > > > > -  connected to a system I2C master this property contains a phandle to that
> > > > > > -  I2C master controller.
> > > > > > -- clock-names: See dw_hdmi.txt. The "cec" clock is optional.
> > > > > > -- clock-names: May contain "cec" as defined in dw_hdmi.txt.
> > > > > > -- clock-names: May contain "grf", power for grf io.
> > > > > > -- clock-names: May contain "vpll", external clock for some hdmi phy.
> > > > > > -- phys: from general PHY binding: the phandle for the PHY device.
> > > > > > -- phy-names: Should be "hdmi" if phys references an external phy.
> > > > > > -
> > > > > > -Optional pinctrl entry:
> > > > > > -- If you have both a "unwedge" and "default" pinctrl entry, dw_hdmi
> > > > > > -  will switch to the unwedge pinctrl state for 10ms if it ever gets an
> > > > > > -  i2c timeout.  It's intended that this unwedge pinctrl entry will
> > > > > > -  cause the SDA line to be driven low to work around a hardware
> > > > > > -  errata.
> > > > > > -
> > > > > > -Example:
> > > > > > -
> > > > > > -hdmi: hdmi@ff980000 {
> > > > > > -	compatible = "rockchip,rk3288-dw-hdmi";
> > > > > > -	reg = <0xff980000 0x20000>;
> > > > > > -	reg-io-width = <4>;
> > > > > > -	ddc-i2c-bus = <&i2c5>;
> > > > > > -	rockchip,grf = <&grf>;
> > > > > > -	interrupts = <GIC_SPI 103 IRQ_TYPE_LEVEL_HIGH>;
> > > > > > -	clocks = <&cru  PCLK_HDMI_CTRL>, <&cru SCLK_HDMI_HDCP>;
> > > > > > -	clock-names = "iahb", "isfr";
> > > > > > -	ports {
> > > > > > -		hdmi_in: port {
> > > > > > -			#address-cells = <1>;
> > > > > > -			#size-cells = <0>;
> > > > > > -			hdmi_in_vopb: endpoint@0 {
> > > > > > -				reg = <0>;
> > > > > > -				remote-endpoint = <&vopb_out_hdmi>;
> > > > > > -			};
> > > > > > -			hdmi_in_vopl: endpoint@1 {
> > > > > > -				reg = <1>;
> > > > > > -				remote-endpoint = <&vopl_out_hdmi>;
> > > > > > -			};
> > > > > > -		};
> > > > > > -	};
> > > > > > -};
> > > > > > diff --git a/Documentation/devicetree/bindings/display/rockchip/rockchip,dw-hdmi.yaml b/Documentation/devicetree/bindings/display/rockchip/rockchip,dw-hdmi.yaml
> > > > > > new file mode 100644
> > > > > > index 000000000000..8ff544ae0ac2
> > > > > > --- /dev/null
> > > > > > +++ b/Documentation/devicetree/bindings/display/rockchip/rockchip,dw-hdmi.yaml
> > > > > > @@ -0,0 +1,178 @@
> > > > > > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> > > > > > +%YAML 1.2
> > > > > > +---
> > > > > > +$id: http://devicetree.org/schemas/display/rockchip/rockchip,dw-hdmi.yaml#
> > > > > > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > > > > > +
> > > > > > +title: Rockchip DWC HDMI TX Encoder
> > > > > > +
> > > > > > +maintainers:
> > > > > > +  - Mark Yao <mark.yao@rock-chips.com>
> > > > > > +
> > > > > > +description: |
> > > > > > +  The HDMI transmitter is a Synopsys DesignWare HDMI 1.4 TX controller IP
> > > > > > +  with a companion PHY IP.
> > > > > > +
> > > > > > +allOf:
> > > > > > +  - $ref: ../bridge/synopsys,dw-hdmi.yaml#
> > > > > > +
> > > > > > +properties:
> > > > > > +  compatible:
> > > > > > +    enum:
> > > > > > +      - rockchip,rk3228-dw-hdmi
> > > > > > +      - rockchip,rk3288-dw-hdmi
> > > > > > +      - rockchip,rk3328-dw-hdmi
> > > > > > +      - rockchip,rk3399-dw-hdmi
> > > > > > +
> > > > > > +  reg: true
> > > > > > +
> > > > > > +  reg-io-width:
> > > > > > +    const: 4
> > > > > > +
> > > > > > +  clocks:
> > > > > > +    minItems: 2
> > > > > > +    maxItems: 5
> > > > > > +    items:
> > > > > > +      - description: The bus clock for either AHB and APB
> > > > > > +      - description: The internal register configuration clock
> > > > > > +      - description: The HDMI CEC controller main clock
> > > > > > +      - description: Power for GRF IO
> > > > > > +      - description: External clock for some HDMI PHY
> > > > > > +
> > > > > > +  clock-names:
> > > > > > +    minItems: 2
> > > > > > +    maxItems: 5
> > > > > > +    items:
> > > > > > +      - const: iahb
> > > > > > +      - const: isfr
> > > > > > +      - enum:
> > > > > > +        - cec
> > > > > > +        - grf
> > > > > > +        - vpll
> > > > > > +      - enum:
> > > > > > +        - cec
> > > > > > +        - grf
> > > > > > +        - vpll
> > > > > > +      - enum:
> > > > > > +        - cec
> > > > > > +        - grf
> > > > > > +        - vpll
> > > > >
> > > > > IIRC Rob wanted us to standardize the order of the clocks if possible,
> > > > > since it's a pain to support properly here, and your description won't
> > > > > match what you describe here either (and in general it's just a best
> > > > > practice), so if all your DTs have the same order you should just set
> > > > > that order in stone.
> > > >
> > > > But how do we handle the case where any of the cec, grf and vpll clocks
> > > > can be set ? Assuming, for instance, that
> > > >
> > > > 	clock-names = "iahb", "isfr", "cec";
> > > > 	clock-names = "iahb", "isfr", "vpll";
> > > > 	clock-names = "iahb", "isfr", "cec", "vpll";
> > > >
> > > > would all be valid.
> > >
> > > It would be painful then...
> > >
> > > The easiest way to do so would be to simply use an enum there, and not
> > > bother checking the array at all. You'll get a warning if there's
> > > multiple occurences of the same string, and I guess that's what you
> > > would be really concerned about.
> > >
> > > However, now that I think about it, what's the interaction between the
> > > generic binding and this one when it comes to the third clock? The
> > > generic one expects it to be cec, and here you have other options?
> >
> > I'm not too familiar with the platform, but as far as I understand, any
> > of the cec, grf and vpll clock is optional (if someone could confirm
> > that, it would be useful). I don't care so much about the order, but
> > iahb and isfr are mandatory, and thus need to be specified as two const
> > items in the beginning as far as I understand. It would be nice to set
> > something along the lines of
> >
> >   minItems: 2
> >   maxItems: 5
> >   items:
> >     - const: iahb
> >     - const: isfr
> >     - enum:
> >       - cec
> >       - grf
> >       - vpll
> 
> I guess you could do something like:
> 
> in the generic schema:
> 
> clock-names:
>   allOf:
>     - minItems: 2
>     - enum:
>        - iahb
>        - isfr
>        - cec
>       additonalItems: true
>     - items:
>       - iahb
>       - isfr
> 
> Or something along those lines, I haven't tested it, but the basic
> idea is that you want to enforce that:
>   a) there's a minimum of two clocks
>   b) valid clock names are iahb, isfr and cec, but we will allow more
>   c) the first two clocks are iahb and isfr

Interesting idea. I've tried

  clock-names:
    allOf:
      - minItems: 2
      - enum:
        - iahb
        - isfr
        - cec
        additionalItems: true
      - items:
        - const: iahb
        - const: isfr

in the base synopsys,dw-hdmi.yaml schema, and

  clock-names:
    maxItems: 2

in renesas,dw-hdmi.yaml, which resulted in the following validation
errors:

Documentation/devicetree/bindings/display/bridge/renesas,dw-hdmi.example.dt.yaml: hdmi@fead0000: clock-names: ['iahb', 'isfr'] is too long

This is caused by the enum entry.

> Now, on the rockchip binding, we can simply have:
> 
> clock-names:
>   enum:
>     - iahb
>     - isfr
>     - cec
>     - grf
>     - vpll
> 
> This way, here we enforce the available clock names, while keeping the
> constraints set in the generic binding.

-- 
Regards,

Laurent Pinchart
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