[PATCH v3 0/4] drm/dp: Make DP AUX bus usage easier; use it on ps8640

Doug Anderson dianders at chromium.org
Tue May 31 21:03:56 UTC 2022


On Tue, May 10, 2022 at 12:30 PM Douglas Anderson <dianders at chromium.org> wrote:
> This patch is v3 of the first 2 patches from my RFC series ("drm/dp: Improvements
> for DP AUX channel") [1]. I've broken the series in two so we can make
> progress on the two halves separately.
> v2 of this series tries to incorporate all the feedback from v1. Hopefully
> things are less confusing and simpler this time around. The one thing that got
> slightly more confusing is that the done_probing() callback can't return
> -EPROBE_DEFER in most cases so we have to adjust drivers a little more.
> v3 takes Dmitry's advice on v2. This now introduces
> devm_drm_bridge_add() (in an extra patch), splits some fixups into
> their own patch, uses a new name for functions, and requires an
> explicit call to done_probing if you have no children.
> The idea for this series came up during the review process of
> Sankeerth's series trying to add eDP for Qualcomm SoCs [2].
> This _doesn't_ attempt to fix the Analogix driver. If this works out,
> ideally someone can post a patch up to do that.
> NOTE: I don't have any ps8640 devices that _don't_ use the aux panel
> underneath them, so I'm relying on code inspection to make sure I
> didn't break those. If someone sees that I did something wrong for
> that case then please yell!
> [1] https://lore.kernel.org/r/20220409023628.2104952-1-dianders@chromium.org/
> [2] https://lore.kernel.org/r/1648656179-10347-2-git-send-email-quic_sbillaka@quicinc.com/
> Changes in v3:
> - Adapt to v3 changes in aux bus.
> - Don't call done_probing() if there are no children; return -ENODEV.
> - Patch ("drm/bridge: Add devm_drm_bridge_add()") new for v3.
> - Patch ("drm/dp: Export symbol / kerneldoc fixes...") split for v3.
> - Split out EXPORT_SYMBOL and kerneldoc fixes to its own patch.
> - Use devm_drm_bridge_add() to simplify.
> - Used Dmitry's proposed name: of_dp_aux_populate_bus()
> Changes in v2:
> - Change to assume exactly one device.
> - Have a probe callback instead of an extra sub device.
> - Rewrote atop new method introduced by patch #1.
> Douglas Anderson (4):
>   drm/dp: Export symbol / kerneldoc fixes for DP AUX bus
>   drm/dp: Add callbacks to make using DP AUX bus properly easier
>   drm/bridge: Add devm_drm_bridge_add()
>   drm/bridge: parade-ps8640: Handle DP AUX more properly
>  drivers/gpu/drm/bridge/parade-ps8640.c   |  74 +++++---
>  drivers/gpu/drm/display/drm_dp_aux_bus.c | 211 +++++++++++++++--------
>  drivers/gpu/drm/drm_bridge.c             |  23 +++
>  include/drm/display/drm_dp_aux_bus.h     |  34 +++-
>  include/drm/drm_bridge.h                 |   1 +
>  5 files changed, 238 insertions(+), 105 deletions(-)

I'm hoping to get some review for this series. Anyone? Dmitry: I know
you looked at earlier versions of this series. I guess you're happy
enough with it now but don't feel enough ownership to give a full


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