linux-kernel - Re: [PATCH v1 4/4] drm/panel: ili9806e: Break some CMDS into helper functions

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Message-ID: <4f3b24d6-9638-49d0-8308-00da09c7ed76@linaro.org>
Date: Fri, 12 Jul 2024 16:56:30 +0200
From: neil.armstrong@...aro.org
To: Doug Anderson <dianders@...omium.org>,
 cong yang <yangcong5@...qin.corp-partner.google.com>
Cc: Michael Walle <mwalle@...nel.org>, quic_jesszhan@...cinc.com,
 linus.walleij@...aro.org, airlied@...il.com, dmitry.baryshkov@...aro.org,
 dri-devel@...ts.freedesktop.org, devicetree@...r.kernel.org,
 linux-kernel@...r.kernel.org
Subject: Re: [PATCH v1 4/4] drm/panel: ili9806e: Break some CMDS into helper
 functions

On 11/07/2024 21:36, Doug Anderson wrote:
> Hi,
> 
> On Wed, Jul 10, 2024 at 6:09 PM cong yang
> <yangcong5@...qin.corp-partner.google.com> wrote:
>>
>> Hi,
>>
>> Michael Walle <mwalle@...nel.org> 于2024年7月11日周四 03:38写道：
>>>
>>> On Wed Jul 10, 2024 at 9:12 PM CEST, Doug Anderson wrote:
>>>> Hi,
>>>>
>>>> On Wed, Jul 10, 2024 at 2:02 AM Michael Walle <mwalle@...nel.org> wrote:
>>>>>
>>>>> On Wed Jul 10, 2024 at 10:47 AM CEST, Cong Yang wrote:
>>>>>> Break select page cmds into helper function.
>>>>>
>>>>> Why though? I don't find that anything easier to read. In fact, I
>>>>> deliberately chose not to factor that out into a function. It's just
>>>>> a sequence of magic commands, taken straight from the datasheet. So,
>>>>> I'd like to keep it that way.
>>>>
>>>> The consensus of previous discussion on the lists was that folks
>>>> agreed that we should, where possible, make it more obvious what these
>>>> magic sequences of commands were doing. IMO separating out the page
>>>> switch command helps. Certainly I'm always happy to hear other
>>>> opinions, though.
>>>
>>> Fair enough, but in that case, one should take the datasheet (which
>>> you can find online) and replace all the magic numbers with the
>>> correct command names from it. E.g. 0xff is the ENEXTC register. To
>>> be clear, I'm not just talking about the "switch page command".
>>>
>>> As patch stands, I don't see much value, TBH. On the contrary, you
>>> make it harder to compare it with the Ortustech panel datasheet.
>>>
>>> just my 2c,
>>> -michael
>>
>> If all drivers replace all the magic numbers with the correct command names,
>> it will be a huge amount of work (assuming that the datasheet can be found).
>>   I am afraid I don't have enough time to complete it.  Thanks.
> 
> Makes sense. I'd be interested in hearing the opinion of others in the
> DRM community about whether they'd prefer to land something long this
> patch as-is or drop it.

I don't have a strong opinion, but I think only changing the switch
page operations doesn't make a lot of sense by itself.

Having a much larger register coverage would be preferred.

Neil

> 
> -Doug