Re: [PATCH] drm/dsi: Add _NO_ to MIPI_DSI_* flags disabling features

[Nicolas Boichat <drinkcat@chromium.org>]

On Mon, Feb 22, 2021 at 3:08 AM Laurent Pinchart
<laurent.pinchart@ideasonboard.com> wrote:
>
> Hi Nicolas,
>
> Thank you for the patch.
>
> On Thu, Feb 11, 2021 at 11:33:55AM +0800, Nicolas Boichat wrote:
> > Many of the DSI flags have names opposite to their actual effects,
> > e.g. MIPI_DSI_MODE_EOT_PACKET means that EoT packets will actually
> > be disabled. Fix this by including _NO_ in the flag names, e.g.
> > MIPI_DSI_MODE_NO_EOT_PACKET.
> >
> > Signed-off-by: Nicolas Boichat <drinkcat@chromium.org>
>
> This looks good to me, it increases readability.
>
> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
>
> Please however see the end of the mail for a comment.
>
> > ---
> > I considered adding _DISABLE_ instead, but that'd make the
> > flag names a big too long.
> >
> > Generated with:
> > flag=MIPI_DSI_MODE_VIDEO_HFP; git grep $flag | cut -f1 -d':' | \
> >   xargs -I{} sed -i -e "s/$flag/MIPI_DSI_MODE_VIDEO_NO_HFP/" {}
> > flag=MIPI_DSI_MODE_VIDEO_HBP; git grep $flag | cut -f1 -d':' | \
> >   xargs -I{} sed -i -e "s/$flag/MIPI_DSI_MODE_VIDEO_NO_HBP/" {}
> > flag=MIPI_DSI_MODE_VIDEO_HSA; git grep $flag | cut -f1 -d':' | \
> >   xargs -I{} sed -i -e "s/$flag/MIPI_DSI_MODE_VIDEO_NO_HSA/" {}
> > flag=MIPI_DSI_MODE_EOT_PACKET; git grep $flag | cut -f1 -d':' | \
> >   xargs -I{} sed -i -e "s/$flag/MIPI_DSI_MODE_NO_EOT_PACKET/" {}
> > (then minor format changes)
>
> Ever tried coccinelle ? :-)

Fun project for next time ,-)

>
> >  drivers/gpu/drm/bridge/adv7511/adv7533.c             | 2 +-
> >  drivers/gpu/drm/bridge/analogix/anx7625.c            | 2 +-
> >  drivers/gpu/drm/bridge/cdns-dsi.c                    | 4 ++--
> >  drivers/gpu/drm/bridge/tc358768.c                    | 2 +-
> >  drivers/gpu/drm/exynos/exynos_drm_dsi.c              | 8 ++++----
> >  drivers/gpu/drm/mcde/mcde_dsi.c                      | 2 +-
> >  drivers/gpu/drm/mediatek/mtk_dsi.c                   | 2 +-
> >  drivers/gpu/drm/msm/dsi/dsi_host.c                   | 8 ++++----
> >  drivers/gpu/drm/panel/panel-asus-z00t-tm5p5-n35596.c | 2 +-
> >  drivers/gpu/drm/panel/panel-dsi-cm.c                 | 2 +-
> >  drivers/gpu/drm/panel/panel-elida-kd35t133.c         | 2 +-
> >  drivers/gpu/drm/panel/panel-khadas-ts050.c           | 2 +-
> >  drivers/gpu/drm/panel/panel-leadtek-ltk050h3146w.c   | 2 +-
> >  drivers/gpu/drm/panel/panel-leadtek-ltk500hd1829.c   | 2 +-
> >  drivers/gpu/drm/panel/panel-novatek-nt35510.c        | 2 +-
> >  drivers/gpu/drm/panel/panel-osd-osd101t2587-53ts.c   | 2 +-
> >  drivers/gpu/drm/panel/panel-samsung-s6d16d0.c        | 2 +-
> >  drivers/gpu/drm/panel/panel-samsung-s6e63j0x03.c     | 2 +-
> >  drivers/gpu/drm/panel/panel-samsung-s6e63m0-dsi.c    | 2 +-
> >  drivers/gpu/drm/panel/panel-samsung-s6e8aa0.c        | 4 ++--
> >  drivers/gpu/drm/panel/panel-sharp-ls043t1le01.c      | 2 +-
> >  drivers/gpu/drm/panel/panel-simple.c                 | 2 +-
> >  drivers/gpu/drm/panel/panel-sony-acx424akp.c         | 2 +-
> >  drivers/gpu/drm/panel/panel-xinpeng-xpp055c272.c     | 2 +-
> >  include/drm/drm_mipi_dsi.h                           | 8 ++++----
> >  25 files changed, 36 insertions(+), 36 deletions(-)
> >
> > []
> > diff --git a/include/drm/drm_mipi_dsi.h b/include/drm/drm_mipi_dsi.h
> > index 360e6377e84b..ba91cf22af51 100644
> > --- a/include/drm/drm_mipi_dsi.h
> > +++ b/include/drm/drm_mipi_dsi.h
> > @@ -119,15 +119,15 @@ struct mipi_dsi_host *of_find_mipi_dsi_host_by_node(struct device_node *node);
> >  /* enable hsync-end packets in vsync-pulse and v-porch area */
> >  #define MIPI_DSI_MODE_VIDEO_HSE              BIT(4)
>
> We're mixing bits that enable a feature and bits that disable a feature.
> Are these bits defined in the DSI spec, or internal to DRM ? In the
> latter case, would it make sense to standardize on one "polarity" ? That
> would be a more intrusive change in drivers though.

Yes, that'd require auditing every single code path and reverse the
logic as needed. I'm not volunteering for that ,-P (hopefully the
current change is still an improvement).

Hopefully real DSI experts can comment (Andrzej?), I think the default
are sensible settings?


>
> >  /* disable hfront-porch area */
> > -#define MIPI_DSI_MODE_VIDEO_HFP              BIT(5)
> > +#define MIPI_DSI_MODE_VIDEO_NO_HFP   BIT(5)
> >  /* disable hback-porch area */
> > -#define MIPI_DSI_MODE_VIDEO_HBP              BIT(6)
> > +#define MIPI_DSI_MODE_VIDEO_NO_HBP   BIT(6)
> >  /* disable hsync-active area */
> > -#define MIPI_DSI_MODE_VIDEO_HSA              BIT(7)
> > +#define MIPI_DSI_MODE_VIDEO_NO_HSA   BIT(7)
> >  /* flush display FIFO on vsync pulse */
> >  #define MIPI_DSI_MODE_VSYNC_FLUSH    BIT(8)
> >  /* disable EoT packets in HS mode */
> > -#define MIPI_DSI_MODE_EOT_PACKET     BIT(9)
> > +#define MIPI_DSI_MODE_NO_EOT_PACKET  BIT(9)
> >  /* device supports non-continuous clock behavior (DSI spec 5.6.1) */
> >  #define MIPI_DSI_CLOCK_NON_CONTINUOUS        BIT(10)
> >  /* transmit data in low power */
>
> --
> Regards,
>
> Laurent Pinchart