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

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Message-ID: <CAD=FV=V5fYweYUoeYD=8qa_jTpF2P_ZjHKJrz0o3ikgrH4XJKQ@mail.gmail.com>
Date: Fri, 12 Jul 2024 08:50:33 -0700
From: Doug Anderson <dianders@...omium.org>
To: neil.armstrong@...aro.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

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.

-Doug