Re: [PATCH 1/9] dt-bindings: msm/dp: drop extra p1 region

[Kuogee Hsieh <quic_khsieh@quicinc.com>]

On 7/8/2022 12:38 PM, Abhinav Kumar wrote:
> + kuogee
>
> On 7/8/2022 12:27 PM, Stephen Boyd wrote:
>> Quoting Dmitry Baryshkov (2022-07-07 20:46:43)
>>> On 08/07/2022 04:28, Stephen Boyd wrote:
>>>> Quoting Dmitry Baryshkov (2022-07-07 14:31:56)
>>>>> The p1 region was probably added by mistake, none of the DTS files
>>>>> provides one (and the driver source code also doesn't use one). 
>>>>> Drop it
>>>>> now.
>>>>
>>>> Yes, looks like the driver doesn't use it.
>>>>
>>>>>
>>>>> Fixes: 687825c402f1 ("dt-bindings: msm/dp: Change reg definition")
>>>>> Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
>>>>> ---
>>>>> Documentation/devicetree/bindings/display/msm/dp-controller.yaml | 
>>>>> 1 -
>>>>>    1 file changed, 1 deletion(-)
>>>>>
>>>>> diff --git 
>>>>> a/Documentation/devicetree/bindings/display/msm/dp-controller.yaml 
>>>>> b/Documentation/devicetree/bindings/display/msm/dp-controller.yaml
>>>>> index 94bc6e1b6451..d6bbe58ef9e8 100644
>>>>> --- 
>>>>> a/Documentation/devicetree/bindings/display/msm/dp-controller.yaml
>>>>> +++ 
>>>>> b/Documentation/devicetree/bindings/display/msm/dp-controller.yaml
>>>>> @@ -29,7 +29,6 @@ properties:
>>>>>          - description: aux register block
>>>>>          - description: link register block
>>>>>          - description: p0 register block
>>>>> -      - description: p1 register block
>>>>
>>>> The p1 registers exist on sc7180. They start where the example starts,
>>>> at 0xae91400.
>>>
>>> Do they exist on e.g. sc7280? In other words, should we add the region
>>> to the DTS? For now I'm going to mark it as optional.
>>>
>>
>> Yes I see the same address for P1 on sc7280. Maybe it's a typo? Abhinav,
>> can you confirm?
>
> P1 block does exist on sc7280 and yes its address is same as the 
> address mentioned in sc7180. So its not a typo.
>
> Yes, we are not programming this today but I would prefer to keep this 
> as optional.
>
> I did sync up with Kuogee on this change this morning, we will check a 
> few things internally on the P1 block's usage as to which use-cases we 
> need to program it for and update here.
>
P1 block is for dp MST application.  This allow two dp streams can be 
mux into same DP phy.

We should keep it since we may support MST later.

> The idea behind having this register space listed in the yaml is thats 
> how the software documents have the blocks listed so dropping P1 block 
> just because its unused seemed wrong to me. Optional seems more 
> appropriate.
>
> Thanks
>
> Abhinav