Re: [v1 1/3] dt-bindings: msm/dsi: Add yaml schema for 7nm DSI PHY

From: rajeevny@codeaurora.org
To: Jonathan Marek <jonathan@marek.ca>
Cc: Rob Herring <robh@kernel.org>,
	robh+dt@kernel.org, dri-devel@lists.freedesktop.org,
	linux-arm-msm@vger.kernel.org, freedreno@lists.freedesktop.org,
	devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
	sean@poorly.run, robdclark@gmail.com, abhinavk@codeaurora.org,
	kalyan_t@codeaurora.org, mkrishn@codeaurora.org
Subject: Re: [v1 1/3] dt-bindings: msm/dsi: Add yaml schema for 7nm DSI PHY
Date: Fri, 18 Jun 2021 16:09:17 +0530	[thread overview]
Message-ID: <a736c5e48907bc2da064f98d94dff9da@codeaurora.org> (raw)
In-Reply-To: <a453734a-ab1f-bf35-9272-0b94c713f05b@marek.ca>

On 17-06-2021 20:37, Jonathan Marek wrote:
> On 6/16/21 1:50 AM, rajeevny@codeaurora.org wrote:
>> On 03-06-2021 01:32, rajeevny@codeaurora.org wrote:
>>> On 02-06-2021 02:28, Rob Herring wrote:
>>>> On Mon, May 31, 2021 at 07:03:53PM +0530, Rajeev Nandan wrote:
>>> 
>>>>> +
>>>>> +properties:
>>>>> +  compatible:
>>>>> +    oneOf:
>>>>> +      - const: qcom,dsi-phy-7nm
>>>> 
>>>> When would one use this?
>>> This is for SM8250.
>>> 
>>>> 
>>>>> +      - const: qcom,dsi-phy-7nm-7280
>>>>> +      - const: qcom,dsi-phy-7nm-8150
>>>> 
>>>> These don't look like full SoC names (sm8150?) and it's
>>>> <vendor>,<soc>-<block>.
>>> 
>>> Thanks, Rob, for the review.
>>> 
>>> I just took the `compatible` property currently used in the DSI PHY 
>>> driver
>>> (drivers/gpu/drm/msm/dsi/phy/dsi_phy.c), and added a new entry for 
>>> sc7280.
>>> A similar pattern of `compatible` names are used in other variants of 
>>> the
>>> DSI PHY driver e.g. qcom,qcom,dsi-phy-10nm-8998, 
>>> qcom,dsi-phy-14nm-660 etc.
>>> 
>>> The existing compatible names "qcom,dsi-phy-7nm-8150" (SoC at the 
>>> end) make
>>> some sense, if we look at the organization of the dsi phy driver 
>>> code.
>>> I am new to this and don't know the reason behind the current code
>>> organization and this naming.
>>> 
>>> Yes, I agree with you, we should use full SoC names. Adding
>>> the SoC name at the end does not feel very convincing, so I will 
>>> change this
>>> to the suggested format e.g. "qcom,sm8250-dsi-phy-7nm", and will 
>>> rename the
>>> occurrences in the driver and device tree accordingly.
>>> Do I need to make changes for 10nm, 14nm, 20nm, and 28nm DSI PHY too?
>>> Bindings doc for these PHYs recently got merged to msm-next [1]
>>> 
>>> 
>>> [1]
>>> https://gitlab.freedesktop.org/drm/msm/-/commit/8fc939e72ff80116c090aaf03952253a124d2a8e
>> 
>> Hi Rob,
>> 
>> I missed adding "robh+dt@kernel.org" earlier in this thread.
>> 
>> Please check my response to your review comments. Regarding your 
>> suggestion to use <vendor>,<soc>-<block> format for compatible 
>> property, should I also upload a new patch to make changes in 10nm, 
>> 14nm, 20nm, and 28nm DSI PHY DT bindings?
>> 
>> Thanks,
>> Rajeev
>> 
> 
> Hi,
> 
> I missed this and ended up sending a similar patch a week later (as
> part of my cphy series, because I needed it to add a "phy-type"
> property).
> 
> "qcom,dsi-phy-7nm" and "qcom,dsi-phy-7nm-8150" aren't new compatibles,
> they were previously documented in the .txt bindings, which are
> getting removed, but the new .yaml bindings didn't include them.
> Documenting them is just a fixup to that patch [1] which is already
> R-B'd by RobH (and has similar compatibles such as "qcom,dsi-phy-10nm"
> and "qcom,dsi-phy-10nm-8998
> ").
> 
> You can use a different/better naming scheme for sc7280, but changing
> the others has nothing to do with adding support for sc7280.
> 
> [1]
> https://gitlab.freedesktop.org/drm/msm/-/commit/8fc939e72ff80116c090aaf03952253a124d2a8e

Hi Jonathan,

I will discard this patch and will add the bindings for the sc7280 on 
top of your patch [1].

[1] 
https://lore.kernel.org/linux-arm-msm/20210617144349.28448-2-jonathan@marek.ca/

Thanks,
Rajeev