[PATCH v3 0/4] drm/dp: Introduce wait_hpd_asserted() for the DP AUX bus

[Douglas Anderson <dianders@chromium.org>]

This is the 2nd four 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 changes to add wait_hpd_asserted() instead of
is_hpd_asserted(). This allows us to move the extra delay needed for
ps8640 into the ps8640 driver itself.

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.

[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:
- Don't check "hpd_asserted" boolean when unset.
- Handle errors from gpiod_get_value_cansleep() properly.

Changes in v2:
- Change is_hpd_asserted() to wait_hpd_asserted()

Douglas Anderson (4):
  drm/dp: Add wait_hpd_asserted() callback to struct drm_dp_aux
  drm/panel-edp: Take advantage of wait_hpd_asserted() in struct
    drm_dp_aux
  drm/panel: atna33xc20: Take advantage of wait_hpd_asserted() in struct
    drm_dp_aux
  drm/bridge: parade-ps8640: Provide wait_hpd_asserted() in struct
    drm_dp_aux

 drivers/gpu/drm/bridge/parade-ps8640.c        | 34 +++++++++------
 drivers/gpu/drm/panel/panel-edp.c             | 33 ++++++++++-----
 .../gpu/drm/panel/panel-samsung-atna33xc20.c  | 41 +++++++++++++------
 include/drm/dp/drm_dp_helper.h                | 26 ++++++++++++
 4 files changed, 98 insertions(+), 36 deletions(-)

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