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[v4,00/15] eDP: Support probing eDP panels dynamically instead of hardcoding

Message ID 20210909210032.465570-1-dianders@chromium.org
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Series eDP: Support probing eDP panels dynamically instead of hardcoding | expand

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Doug Anderson Sept. 9, 2021, 9 p.m. UTC 
The goal of this patch series is to move away from hardcoding exact
eDP panels in device tree files. As discussed in the various patches
in this series (I'm not repeating everything here), most eDP panels
are 99% probable and we can get that last 1% by allowing two "power
up" delays to be specified in the device tree file and then using the
panel ID (found in the EDID) to look up additional power sequencing
delays for the panel.

This patch series is the logical contiunation of a previous patch
series where I proposed solving this problem by adding a
board-specific compatible string [1]. In the discussion that followed
it sounded like people were open to something like the solution
proposed in this new series.

In version 2 I got rid of the idea that we could have a "fallback"
compatible string that we'd use if we didn't recognize the ID in the
EDID. This simplifies the bindings a lot and the implementation
somewhat. As a result of not having a "fallback", though, I'm not
confident in transitioning any existing boards over to this since
we'll have to fallback to very conservative timings if we don't
recognize the ID from the EDID and I can't guarantee that I've seen
every panel that might have shipped on an existing product. The plan
is to use "edp-panel" only on new boards or new revisions of old
boards where we can guarantee that every EDID that ships out of the
factory has an ID in the table.

Version 3 of this series now splits out all eDP panels to their own
driver and adds the generic eDP panel support to this new driver. I
believe this is what Sam was looking for [2].

Version 4 of this series is mostly small fixes / renames from review
feedback. It's largely the same as v3. Other than naming /
description / comment changes, the differences are:
- Dropped the MIPS config patch as per request.
- Reorder config patches first.
- Added a new patch to use the panel ID scheme for quirks.
- Landed the reorder of logicpd_type_28 / mitsubishi_aa070mc01
It could possibly be ready to land?

[1] https://lore.kernel.org/r/YFKQaXOmOwYyeqvM@google.com/
[2] https://lore.kernel.org/r/YRTsFNTn%2FT8fLxyB@ravnborg.org/

Changes in v4:
- "u8 *edid" => "void *edid" to avoid cast.
- ("Use new encoded panel id style for quirks matching") new for v4.
- Don't put kmalloc() in the "if" test even if the old code did.
- Don't refer to "panel-simple" in commit message.
- PANEL_SIMPLE_EDP => PANEL_EDP
- Remove "non-eDP" in panel-simple description.
- Reordered config patches to be before code patch
- decode_edid_id() => drm_edid_decode_panel_id()
- drm_do_get_edid_blk0() => drm_do_get_edid_base_block()
- drm_get_panel_id() => drm_edid_get_panel_id()
- encode_edid_id() => drm_edid_encode_panel_id()
- panel-simple-edp => panel-edp
- split panel id extraction out to its own function.

Changes in v3:
- ("Better describe eDP panel delays") new for v3.
- ("Don't re-read the EDID every time") moved to eDP only patch.
- ("Non-eDP panels don't need "HPD" handling") new for v3.
- Add AUO B116XAN06.1 to table.
- Add Sharp LQ116M1JW10 to table.
- Adjust endianness of product ID.
- Change init order to we power at the end.
- Decode hex product ID w/ same endianness as everyone else.
- Fallback to conservative delays if panel not recognized.
- Fix "prepare_to_enable" patch new for v3.
- Generic "edp-panel" handled by the eDP panel driver now.
- Move wayward panels patch new for v3.
- Rename delays more generically so they can be reused.
- Split eDP panels patch new for v3.
- Split the delay structure out patch just on eDP now.

Changes in v2:
- Add "-ms" suffix to delays.
- Don't support a "fallback" panel. Probed panels must be probed.
- No longer allow fallback to panel-simple.
- Not based on patch to copy "desc"--just allocate for probed panels.

Douglas Anderson (15):
  dt-bindings: drm/panel-simple-edp: Introduce generic eDP panels
  drm/edid: Break out reading block 0 of the EDID
  drm/edid: Allow querying/working with the panel ID from the EDID
  drm/edid: Use new encoded panel id style for quirks matching
  ARM: configs: Everyone who had PANEL_SIMPLE now gets PANEL_EDP
  arm64: defconfig: Everyone who had PANEL_SIMPLE now gets PANEL_EDP
  drm/panel-edp: Split eDP panels out of panel-simple
  drm/panel-edp: Move some wayward panels to the eDP driver
  drm/panel-simple: Non-eDP panels don't need "HPD" handling
  drm/panel-edp: Split the delay structure out
  drm/panel-edp: Better describe eDP panel delays
  drm/panel-edp: hpd_reliable shouldn't be subtraced from hpd_absent
  drm/panel-edp: Fix "prepare_to_enable" if panel doesn't handle HPD
  drm/panel-edp: Don't re-read the EDID every time we power off the
    panel
  drm/panel-edp: Implement generic "edp-panel"s probed by EDID

 .../bindings/display/panel/panel-edp.yaml     |  188 ++
 arch/arm/configs/at91_dt_defconfig            |    1 +
 arch/arm/configs/exynos_defconfig             |    1 +
 arch/arm/configs/imx_v6_v7_defconfig          |    1 +
 arch/arm/configs/lpc32xx_defconfig            |    1 +
 arch/arm/configs/multi_v5_defconfig           |    1 +
 arch/arm/configs/multi_v7_defconfig           |    1 +
 arch/arm/configs/omap2plus_defconfig          |    1 +
 arch/arm/configs/qcom_defconfig               |    1 +
 arch/arm/configs/realview_defconfig           |    1 +
 arch/arm/configs/sama5_defconfig              |    1 +
 arch/arm/configs/shmobile_defconfig           |    1 +
 arch/arm/configs/sunxi_defconfig              |    1 +
 arch/arm/configs/tegra_defconfig              |    1 +
 arch/arm/configs/versatile_defconfig          |    1 +
 arch/arm/configs/vexpress_defconfig           |    1 +
 arch/arm64/configs/defconfig                  |    1 +
 drivers/gpu/drm/drm_edid.c                    |  281 ++-
 drivers/gpu/drm/panel/Kconfig                 |   16 +-
 drivers/gpu/drm/panel/Makefile                |    1 +
 drivers/gpu/drm/panel/panel-edp.c             | 1896 +++++++++++++++++
 drivers/gpu/drm/panel/panel-simple.c          | 1072 +---------
 include/drm/drm_edid.h                        |   47 +
 23 files changed, 2355 insertions(+), 1162 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/display/panel/panel-edp.yaml
 create mode 100644 drivers/gpu/drm/panel/panel-edp.c