The primary goal of this series is to try to properly fix EDID reading for eDP panels using the ti-sn65dsi86 bridge.
Previously we had a patch that added EDID reading but it turned out not to work at bootup. This caused some extra churn at bootup as we tried (and failed) to read the EDID several times and also ended up forcing us to use the hardcoded mode at boot. With this patch series I believe EDID reading is reliable at boot now and we never use the hardcoded mode.
High level note: in this series the EDID reading is driven by the panel driver, not by the bridge chip driver. I believe this makes a reasonable amount of sense since the panel driver already _could_ drive reading the EDID if provided with the DDC bus and in future planned work we'll want to give the panel driver the DDC bus (to make decisions based on EDID) and the AUX bus (to control the backlight). There are also planned patches from Laurent to make ti-sn65dsi86 able to drive full DP monitors. In that case the bridge chip will still be in charge of reading the EDID, but it's not hard to make this dynamic.
This series is the logical successor to the 3-part series containing the patch ("drm/bridge: ti-sn65dsi86: Properly get the EDID, but only if refclk") [1].
This patch was tested against drm-misc-next commit a596fcd9cbc7 ("drm/panel: panel-simple: Add missing pm_runtime_dont_use_autosuspend() calls") on a sc7180-trogdor-lazor device.
At v8 now, the bindings patches have been beefed up from v7 and review/ack tags were added. Also allmodconfig was fixed.
Between v2 and v3, high-level view of changes: - stop doing the EDID caching in the core.
Between v3 and v4, high-level view of changes: - EDID reading is actually driven by the panel driver now. See above. - Lots of chicken-and-egg problems solved w/ sub-devices.
Between v4 and v5, high-level view of changes. - Some of the early patches landed, so dropped from series. - New pm_runtime_disable() fix (fixed a patch that already landed). - Added Bjorn's tags to most patches - Fixed problems when building as a module. - Reordered debugfs patch and fixed error handling there. - Dropped last patch. I'm not convinced it's safe w/out more work.
Between v5 and v6, high-level view of changes: - Added the patch ("drm/dp: Allow an early call to register DDC i2c bus") - Many patches had been landed, so only a few "controversial" ones left.
Between v6 and v7, high-level view of changes: - New AUX DP bus!
Between v7 and v8, high-level view of changes: - More bindings work. - Fixed allmodconfig.
[1] https://lore.kernel.org/r/20210304155144.3.I60a7fb23ce4589006bc95c64ab8d15c7...
Changes in v8: - Allow dp-aux-bus to be a module to fix allmodconfig builds - Explain better why HPD needs to be in panel-simple in commit msg. - Separate DP AUX bus binding is new for v8. - ti-sn65dsi86 references the new aux bus bindings.
Changes in v7: - Adjusted commit message to talk about DP AUX bus. - Beefed up commit message in context of the DP AUX bus. - List hpd properties bindings patch new for v7. - Panel now under bridge chip instead of getting a link to ddc-i2c - Patch introducing the DP AUX bus is new for v7. - Patch to allow panel-simple to be DP AUX EP new for v7. - Patch to support for DP AUX bus on ti-sn65dsi86 new for v7. - Patch using the DP AUX for DDC new for v7. - Remove use of now-dropped drm_dp_aux_register_ddc() call. - Set the proper sub-device "dev" pointer in the AUX structure. - ti-sn65dsi86: Add aux-bus child patch new for v7.
Changes in v6: - Use new drm_dp_aux_register_ddc() calls.
Douglas Anderson (11): dt-bindings: display: simple: List hpd properties in panel-simple dt-bindings: drm: Introduce the DP AUX bus dt-bindings: drm/bridge: ti-sn65dsi86: Add aux-bus child dt-bindings: drm/aux-bus: Add an example drm: Introduce the DP AUX bus drm/panel: panel-simple: Allow panel-simple be a DP AUX endpoint device drm/panel: panel-simple: Stash DP AUX bus; allow using it for DDC drm/bridge: ti-sn65dsi86: Promote the AUX channel to its own sub-dev drm/bridge: ti-sn65dsi86: Add support for the DP AUX bus drm/bridge: ti-sn65dsi86: Don't read EDID blob over DDC arm64: dts: qcom: sc7180-trogdor: Move panel under the bridge chip
.../bindings/display/bridge/ti,sn65dsi86.yaml | 20 +- .../bindings/display/dp-aux-bus.yaml | 102 ++++++ .../bindings/display/panel/panel-simple.yaml | 2 + arch/arm64/boot/dts/qcom/sc7180-trogdor.dtsi | 30 +- drivers/gpu/drm/Kconfig | 5 + drivers/gpu/drm/Makefile | 2 + drivers/gpu/drm/bridge/Kconfig | 1 + drivers/gpu/drm/bridge/ti-sn65dsi86.c | 111 ++++-- drivers/gpu/drm/drm_dp_aux_bus.c | 326 ++++++++++++++++++ drivers/gpu/drm/panel/Kconfig | 1 + drivers/gpu/drm/panel/panel-simple.c | 64 +++- include/drm/drm_dp_aux_bus.h | 57 +++ 12 files changed, 665 insertions(+), 56 deletions(-) create mode 100644 Documentation/devicetree/bindings/display/dp-aux-bus.yaml create mode 100644 drivers/gpu/drm/drm_dp_aux_bus.c create mode 100644 include/drm/drm_dp_aux_bus.h