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

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Message-ID: <6766a3b3-82bf-4c37-8631-48a8173d8131@linaro.org>
Date: Wed, 24 Jul 2024 09:59:56 +0200
From: neil.armstrong@...aro.org
To: Doug Anderson <dianders@...omium.org>
Cc: cong yang <yangcong5@...qin.corp-partner.google.com>,
 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 12/07/2024 17:50, Doug Anderson wrote:
> Hi,
> 
> On Fri, Jul 12, 2024 at 7:56 AM <neil.armstrong@...aro.org> wrote:
>>
>> 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.
> 
> Does that mean you think we should drop this whole series? For the
> "panel-ilitek-ili9806e.c" driver dropping seems fine since the switch
> page command (and many of the other blocks of commands) is commented,
> but for the other panels in this series IMO even just getting the
> switch page adds to the readability... I'm happy to just apply patches
> #1-#3 or just drop the series.

Well since we already have the changes, clean and reviewed, let's apply them!

Neil

> 
> -Doug