[RFC PATCH 0/6] drm/dp: Improvements for DP AUX channel

From: Douglas Anderson <dianders@chromium.org>
To: dri-devel@lists.freedesktop.org
Cc: Robert Foss <robert.foss@linaro.org>,
	Hsin-Yi Wang <hsinyi@chromium.org>,
	Dmitry Baryshkov <dmitry.baryshkov@linaro.org>,
	Abhinav Kumar <quic_abhinavk@quicinc.com>,
	Sankeerth Billakanti <quic_sbillaka@quicinc.com>,
	Philip Chen <philipchen@chromium.org>,
	Stephen Boyd <swboyd@chromium.org>,
	Douglas Anderson <dianders@chromium.org>,
	Andrzej Hajda <andrzej.hajda@intel.com>,
	Daniel Vetter <daniel@ffwll.ch>, David Airlie <airlied@linux.ie>,
	Jani Nikula <jani.nikula@intel.com>,
	Jernej Skrabec <jernej.skrabec@gmail.com>,
	Jonas Karlman <jonas@kwiboo.se>,
	Kees Cook <keescook@chromium.org>,
	Laurent Pinchart <Laurent.pinchart@ideasonboard.com>,
	Linus Walleij <linus.walleij@linaro.org>,
	Lyude Paul <lyude@redhat.com>, Maxime Ripard <maxime@cerno.tech>,
	Neil Armstrong <narmstrong@baylibre.com>,
	Sam Ravnborg <sam@ravnborg.org>,
	Thierry Reding <thierry.reding@gmail.com>,
	Thomas Zimmermann <tzimmermann@suse.de>,
	linux-kernel@vger.kernel.org
Subject: [RFC PATCH 0/6] drm/dp: Improvements for DP AUX channel
Date: Fri,  8 Apr 2022 19:36:22 -0700	[thread overview]
Message-ID: <20220409023628.2104952-1-dianders@chromium.org> (raw)

This patch addresses pre-existing issues that came up during the
review process of Sankeerth's series trying to add eDP for Qualcomm
SoCs [1].

It's really sorta two series but jammed into one. The first two
patches fix a problem with ps8640 when the panel doesn't finish
probing right away. The rest of the patches attempt to improve how eDP
panel drivers deal with the HPD signal. NOTE: if everyone hates the
"generic driver" that I added in the first patch, I have a different
version that just adds uses the Linux auxiliary bus stright in
ps8640. I'm happy to switch back to that, but it seemed like a buncha
copy-pasta that I was hoping to avoid.

I haven't done a crazy amount of testing with this, but it seems to
work and I wanted to get something out there. I'll try to do some more
testing next week. This is why I added the tag "RFC". It's entirely
possibled that I've actually caught all the bugs and this is great,
but I just wanted to be sure.

This _doesn't_ attempt to fix the Analogix driver. If this works out,
ideally someone can post a patch up to do that.

[1] https://lore.kernel.org/r/1648656179-10347-2-git-send-email-quic_sbillaka@quicinc.com/

Douglas Anderson (6):
  drm/dp: Helpers to make it easier for drivers to use DP AUX bus
    properly
  drm/bridge: parade-ps8640: Break probe in two to handle DP AUX better
  drm/dp: Add is_hpd_asserted() callback to struct drm_dp_aux
  drm/panel-edp: Take advantage of is_hpd_asserted() in struct
    drm_dp_aux
  drm/panel: atna33xc20: Take advantage of is_hpd_asserted() in struct
    drm_dp_aux
  drm/bridge: parade-ps8640: Provide is_hpd_asserted() in struct
    drm_dp_aux

 drivers/gpu/drm/bridge/parade-ps8640.c        |  87 +++++----
 drivers/gpu/drm/dp/drm_dp_aux_bus.c           | 165 +++++++++++++++++-
 drivers/gpu/drm/panel/panel-edp.c             |  37 +++-
 .../gpu/drm/panel/panel-samsung-atna33xc20.c  |  35 +++-
 include/drm/dp/drm_dp_aux_bus.h               |  58 ++++++
 include/drm/dp/drm_dp_helper.h                |  14 ++
 6 files changed, 353 insertions(+), 43 deletions(-)

-- 
2.35.1.1178.g4f1659d476-goog