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

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Message-ID: <CAHwB_NJ+YEMoL18Sr9HFmTVH_ErDztyF7vxxPFAE0Y2ta3dO0A@mail.gmail.com>
Date: Thu, 11 Jul 2024 09:08:56 +0800
From: cong yang <yangcong5@...qin.corp-partner.google.com>
To: Michael Walle <mwalle@...nel.org>
Cc: Doug Anderson <dianders@...omium.org>, quic_jesszhan@...cinc.com, 
	neil.armstrong@...aro.org, 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,

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.

>
> > > -michael
> > >
> > > > Signed-off-by: Cong Yang <yangcong5@...qin.corp-partner.google.com>
> > > > ---
> > > >  drivers/gpu/drm/panel/panel-ilitek-ili9806e.c | 14 ++++++++++----
> > > >  1 file changed, 10 insertions(+), 4 deletions(-)
> > > >
> > > > diff --git a/drivers/gpu/drm/panel/panel-ilitek-ili9806e.c b/drivers/gpu/drm/panel/panel-ilitek-ili9806e.c
> > > > index e4a44cd26c4d..68fb9a1a4d80 100644
> > > > --- a/drivers/gpu/drm/panel/panel-ilitek-ili9806e.c
> > > > +++ b/drivers/gpu/drm/panel/panel-ilitek-ili9806e.c
> > > > @@ -35,6 +35,12 @@ struct ili9806e_panel {
> > > >       enum drm_panel_orientation orientation;
> > > >  };
> > > >
> > > > +#define ILI9806E_DCS_SWITCH_PAGE     0xff
> > > > +
> > > > +#define ili9806e_switch_page(ctx, page) \
> > > > +     mipi_dsi_dcs_write_seq_multi(ctx, ILI9806E_DCS_SWITCH_PAGE, \
> > > > +                                  0xff, 0x98, 0x06, 0x04, (page))
> > > > +
> > > >  static const char * const regulator_names[] = {
> > > >       "vdd",
> > > >       "vccio",
> > > > @@ -227,7 +233,7 @@ static void ili9806e_dsi_remove(struct mipi_dsi_device *dsi)
> > > >  static void com35h3p70ulc_init(struct mipi_dsi_multi_context *ctx)
> > > >  {
> > > >       /* Switch to page 1 */
> > > > -     mipi_dsi_dcs_write_seq_multi(ctx, 0xff, 0xff, 0x98, 0x06, 0x04, 0x01);
> > > > +     ili9806e_switch_page(ctx, 0x01);
> >
> > I think with your change you should remove the "Switch to page X"
> > comments since they're now obvious. Other than that, I'm happy with:
> >
> > Reviewed-by: Douglas Anderson <dianders@...omium.org>
>