Re: [PATCH v4 3/4] dt-bindings: display: rockchip: Add schema for RK3588 HDMI TX Controller

[Cristian Ciocaltea <cristian.ciocaltea@collabora.com>]

On 8/21/24 6:07 PM, Conor Dooley wrote:
> On Tue, Aug 20, 2024 at 11:12:45PM +0300, Cristian Ciocaltea wrote:
>> On 8/20/24 7:14 PM, Conor Dooley wrote:
>>> On Tue, Aug 20, 2024 at 03:37:44PM +0300, Cristian Ciocaltea wrote:
>>>> On 8/19/24 7:53 PM, Conor Dooley wrote:
>>>>> On Mon, Aug 19, 2024 at 01:29:30AM +0300, Cristian Ciocaltea wrote:
>>>>>> +  rockchip,grf:
>>>>>> +    $ref: /schemas/types.yaml#/definitions/phandle
>>>>>> +    description:
>>>>>> +      Most HDMI QP related data is accessed through SYS GRF regs.
>>>>>> +
>>>>>> +  rockchip,vo1-grf:
>>>>>> +    $ref: /schemas/types.yaml#/definitions/phandle
>>>>>> +    description:
>>>>>> +      Additional HDMI QP related data is accessed through VO1 GRF regs.
>>>>>
>>>>> Why are these required? What prevents you looking up the syscons by
>>>>> compatible?
>>>>
>>>> That is for getting the proper instance:
>>>
>>> Ah, that makes sense. I am, however, curious why these have the same
>>> compatible when they have different sized regions allocated to them.
>>
>> Good question, didn't notice.  I've just checked the TRM and, in both
>> cases, the maximum register offset is within the 0x100 range.  Presumably
>> this is nothing but an inconsistency, as the syscons have been added in
>> separate commits.
> 
> Is that TRM publicly available? I do find it curious that devices sound
> like they have different contents have the same compatible. In my view,
> that is incorrect and they should have unique compatibles if the
> contents (and therefore the programming model) differs.

Don't know if there's an official location to get it from, but a quick
search on internet shows a few repos providing them, e.g. [1].

Comparing "6.14 VO0_GRF Register Description" at pg. 777 with "6.15 VO1_GRF
Register Description" at pg. 786 (from Part1) reveals the layout is mostly
similar, with a few variations though.

[1] https://github.com/FanX-Tek/rk3588-TRM-and-Datasheet

>>
>>>> 	vo0_grf: syscon@fd5a6000 {
>>>> 		compatible = "rockchip,rk3588-vo-grf", "syscon";
>>>> 		reg = <0x0 0xfd5a6000 0x0 0x2000>;
>>>> 		clocks = <&cru PCLK_VO0GRF>;
>>>> 	};
>>>>
>>>> 	vo1_grf: syscon@fd5a8000 {
>>>> 		compatible = "rockchip,rk3588-vo-grf", "syscon";
>>>> 		reg = <0x0 0xfd5a8000 0x0 0x100>;
>>>> 		clocks = <&cru PCLK_VO1GRF>;
>>>> 	};
>