On Tue, Feb 03, 2026 at 11:11:50AM +0100, Luca Ceresoli wrote: > On Tue Feb 3, 2026 at 2:31 AM CET, Damon Ding wrote: > > On 2/2/2026 10:54 AM, Damon Ding wrote: > >> On 1/31/2026 8:33 PM, Luca Ceresoli wrote: > >>> On Wed Dec 17, 2025 at 10:33 AM CET, Damon Ding wrote: > >>>> As suggested by Dmitry, the DRM legacy bridge driver can be pulled > >>>> out of imx/ subdir for multi-platform use. The driver is also renamed > >>>> to make it more generic and suitable for platforms other than i.MX. > >>>> > >>>> Signed-off-by: Damon Ding <[email protected]> > >>>> Suggested-by: Dmitry Baryshkov <[email protected]> > >>>> Tested-by: Marek Szyprowski <[email protected]> > >>>> > >>>> --- > >>>> > >>>> Changes in v7: > >>>> - Rename legacy-bridge to of-display-mode-bridge. > >>>> - Remove unnecessary API drm_bridge_is_legacy(). > >>> > >>> ... > >>> > >>>> --- a/drivers/gpu/drm/bridge/Kconfig > >>>> +++ b/drivers/gpu/drm/bridge/Kconfig > >>>> @@ -244,6 +244,16 @@ config DRM_NXP_PTN3460 > >>>> help > >>>> NXP PTN3460 eDP-LVDS bridge chip driver. > >>>> > >>>> +config DRM_OF_DISPLAY_MODE_BRIDGE > >>>> + tristate > >>>> + depends on DRM_BRIDGE && OF > >>>> + help > >>>> + This is a DRM bridge implementation that uses > >>>> of_get_drm_display_mode > >>>> + to acquire display mode. > >>>> + > >>>> + Newer designs should not use this bridge and should use proper > >>>> panel > >>>> + driver instead. > >>> > >>> "Newer designs should not use this bridge", but in patch 8 you are > >>> introducing a new use ot devm_drm_of_display_mode_bridge(). Shouldn't you > >>> instead "use proper panel driver instead" in patch 8? > >>> > >>> Can you point to the conversation where the converstaion where Dmitry > >>> suggested this change? Maybe it already contains the answer to my > >>> qustion. Also adding a link to that conversation in the commit message > >>> woule be useful. > >>> > >> > >> First of all, thanks for your reviews on this patch series. > >> > >> link: https://lore.kernel.org/all/ > >> xwenycscalzdlpuxytorbiyvej3k7pv3lhxwtadilxq65ipwsv@x5rxm53w5e22/ > >> > >> I think it may be a misleading issue caused by directly copying the > >> previous Kconfig description. Now that the new > >> devm_drm_of_display_mode_bridge() helper has been added, drivers using > >> the panel-bridge framework can rely on it to maintain compatibility with > >> legacy display mode parsing. > > Ah, I think I got the point: the mode description in device tree is legacy, > but the driver itself is not legacy and will be current until we need to > support legacy device tree. Correct? > > If that's correct, this patch looks OK to me with a new Kconfig help text.
The devm_drm_of_display_mode_bridge() function needs documentation though, with a warning that tells it must not be used in new drivers. Catching new users in checkpatch.pl (or somewhere else) would be ideal. I would also not create a separate module for this and move the function to drm_bridge.c, but I don't mind that much if the consensus is that a separate module is better. > >> It would be better to update the comment as follows: > >> > >> This is a DRM bridge implementation that uses of_get_drm_display_mode to > >> acquire display mode. > >> > >> It exists for compatibility with legacy display mode parsing, in order > >> to conform to the panel-bridge framework. > >> > > > > Dmitry, what's you take on this? > > Dmitry's opinion would be much more relevant than mine. I don't know much > myself about this driver. -- Regards, Laurent Pinchart
