Re: [PATCH v2 02/12] dt-bindings: display: mediatek: add MT8195 hdmi bindings

[Guillaume Ranquet <granquet@baylibre.com>]

On Thu, 03 Nov 2022 13:45, Krzysztof Kozlowski
<krzysztof.kozlowski@linaro.org> wrote:
>On 02/11/2022 09:31, Guillaume Ranquet wrote:
>> On Fri, 14 Oct 2022 18:08, Krzysztof Kozlowski
>> <krzysztof.kozlowski@linaro.org> wrote:
>>> On 14/10/2022 11:15, Guillaume Ranquet wrote:
>>>> Add mt8195 SoC bindings for hdmi and hdmi-ddc
>>>>
>>>> Signed-off-by: Guillaume Ranquet <granquet@baylibre.com>
>>>> ---
>>>>  .../bindings/display/mediatek/mediatek,hdmi.yaml   | 67 +++++++++++++++++-----
>>>>  .../display/mediatek/mediatek,mt8195-hdmi-ddc.yaml | 51 ++++++++++++++++
>>>>  2 files changed, 104 insertions(+), 14 deletions(-)
>>>>
>>>> diff --git a/Documentation/devicetree/bindings/display/mediatek/mediatek,hdmi.yaml b/Documentation/devicetree/bindings/display/mediatek/mediatek,hdmi.yaml
>>>> index bdaf0b51e68c..955026cd7ca5 100644
>>>> --- a/Documentation/devicetree/bindings/display/mediatek/mediatek,hdmi.yaml
>>>> +++ b/Documentation/devicetree/bindings/display/mediatek/mediatek,hdmi.yaml
>>>> @@ -21,26 +21,21 @@ properties:
>>>>        - mediatek,mt7623-hdmi
>>>>        - mediatek,mt8167-hdmi
>>>>        - mediatek,mt8173-hdmi
>>>> +      - mediatek,mt8195-hdmi
>>>>
>>>>    reg:
>>>>      maxItems: 1
>>>>
>>>> -  interrupts:
>>>> -    maxItems: 1
>>>> -
>>>
>>> This change is not really explained in commit msg...
>>>
>>>>    clocks:
>>>> -    items:
>>>> -      - description: Pixel Clock
>>>> -      - description: HDMI PLL
>>>> -      - description: Bit Clock
>>>> -      - description: S/PDIF Clock
>>>> +    minItems: 4
>>>> +    maxItems: 4
>>>>
>>>>    clock-names:
>>>> -    items:
>>>> -      - const: pixel
>>>> -      - const: pll
>>>> -      - const: bclk
>>>> -      - const: spdif
>>>> +    minItems: 4
>>>> +    maxItems: 4
>>>> +
>>>> +  interrupts:
>>>> +    maxItems: 1
>>>>
>>>>    phys:
>>>>      maxItems: 1
>>>> @@ -58,6 +53,9 @@ properties:
>>>>      description: |
>>>>        phandle link and register offset to the system configuration registers.
>>>>
>>>> +  power-domains:
>>>> +    maxItems: 1
>>>> +
>>>>    ports:
>>>>      $ref: /schemas/graph.yaml#/properties/ports
>>>>
>>>> @@ -86,9 +84,50 @@ required:
>>>>    - clock-names
>>>>    - phys
>>>>    - phy-names
>>>> -  - mediatek,syscon-hdmi
>>>>    - ports
>>>>
>>>> +allOf:
>>>> +  - if:
>>>> +      properties:
>>>> +        compatible:
>>>> +          contains:
>>>> +            const: mediatek,mt8195-hdmi
>>>> +    then:
>>>> +      properties:
>>>> +        clocks:
>>>> +          items:
>>>> +            - description: APB
>>>> +            - description: HDCP
>>>> +            - description: HDCP 24M
>>>> +            - description: Split HDMI
>>>> +        clock-names:
>>>> +          items:
>>>> +            - const: hdmi_apb_sel
>>>> +            - const: hdcp_sel
>>>> +            - const: hdcp24_sel
>>>> +            - const: split_hdmi
>>>> +
>>>> +      required:
>>>> +        - power-domains
>>>> +    else:
>>>> +      properties:
>>>> +        clocks:
>>>> +          items:
>>>> +            - description: Pixel Clock
>>>> +            - description: HDMI PLL
>>>> +            - description: Bit Clock
>>>> +            - description: S/PDIF Clock
>>>> +
>>>> +        clock-names:
>>>> +          items:
>>>> +            - const: pixel
>>>> +            - const: pll
>>>> +            - const: bclk
>>>> +            - const: spdif
>>>> +
>>>> +      required:
>>>> +        - mediatek,syscon-hdmi
>>>> +
>>>>  additionalProperties: false
>>>>
>>>>  examples:
>>>> diff --git a/Documentation/devicetree/bindings/display/mediatek/mediatek,mt8195-hdmi-ddc.yaml b/Documentation/devicetree/bindings/display/mediatek/mediatek,mt8195-hdmi-ddc.yaml
>>>> new file mode 100644
>>>> index 000000000000..0fe0a2a2f17f
>>>> --- /dev/null
>>>> +++ b/Documentation/devicetree/bindings/display/mediatek/mediatek,mt8195-hdmi-ddc.yaml
>>>> @@ -0,0 +1,51 @@
>>>> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
>>>> +%YAML 1.2
>>>> +---
>>>> +$id: http://devicetree.org/schemas/display/mediatek/mediatek,mt8195-hdmi-ddc.yaml#
>>>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
>>>> +
>>>> +title: Mediatek HDMI DDC for mt8195
>>>> +
>>>> +maintainers:
>>>> +  - CK Hu <ck.hu@mediatek.com>
>>>> +  - Jitao shi <jitao.shi@mediatek.com>
>>>> +
>>>> +description: |
>>>> +  The HDMI DDC i2c controller is used to interface with the HDMI DDC pins.
>>>> +
>>>> +properties:
>>>> +  compatible:
>>>> +    enum:
>>>> +      - mediatek,mt8195-hdmi-ddc
>>>
>>> I think I wrote it - you already have bindings for HDMI DDC. I doubt
>>> that these are different and it looks like you model the bindings
>>> according to your driver. That's not the way.
>>
>> Hi Krzysztof,
>>
>> I've made a separate binding as this new IP is integrated into the
>> HDMI hw block.
>> The difference it makes is that the hw is slightly simpler to describe
>> as the IP doesn't
>> have it's own range of registers or an interrupt line.
>>
>> I can use the "legacy mediatek mtk ddc binding" if I modify it to have
>> the reg and
>> interrupt properties not being required for mt8195.
>
>OK, it is reasonable - such stuff should be in commit msg, so we won't
>keep asking.
>

I'll sum this up in the commit msg for V3 then.

>>
>> Would that work better for you?
>>
>>>
>>>> +
>>>> +  clocks:
>>>> +    maxItems: 1
>>>> +
>>>> +  clock-names:
>>>> +    items:
>>>> +      - const: ddc
>>>> +
>>>> +  mediatek,hdmi:
>>>> +    $ref: /schemas/types.yaml#/definitions/phandle
>>>> +    description:
>>>> +      A phandle to the mt8195 hdmi controller
>>>> +
>>>> +required:
>>>> +  - compatible
>>>> +  - clocks
>>>> +  - clock-names
>>>> +
>>>> +additionalProperties: false
>>>> +
>>>> +examples:
>>>> +  - |
>>>> +    #include <dt-bindings/interrupt-controller/arm-gic.h>
>>>> +    #include <dt-bindings/interrupt-controller/irq.h>
>>>> +    hdmiddc0: ddc_i2c {
>>>
>>> Node names should be generic - ddc.
>>> https://devicetree-specification.readthedocs.io/en/latest/chapter2-devicetree-basics.html#generic-names-recommendation
>>>
>>> No underscores in node names.
>>>
>>> Additionally I2C devices have addresses on the bus. Why this one doesn't?
>>>
>>
>> This is an i2c adapter, not a device.
>> And as it lives inside the HDMI hw block, I've omitted using an address here.
>>
>> Is this valid? or should this be expressed differently?
>
>What is an I2C adapter? Did you mean I2C controller (master)?

Yes, a controller.
This is an I2C controller connected to the HDMI connector, it is used
to exchange data on the Display Data Channel with
the display (such as EDID).

Thx,
Guillaume.

>
>Best regards,
>Krzysztof
>