[PATCH v2 00/10] drm/panel and i2c-hid: Allow panels and touchscreens to power sequence together

[Douglas Anderson <dianders@chromium.org>]

The big motivation for this patch series is mostly described in the patch
("drm/panel: Add a way for other devices to follow panel state"), but to
quickly summarize here: for touchscreens that are connected to a panel we
need the ability to power sequence the two device together. This is not a
new need, but so far we've managed to get by through a combination of
inefficiency, added costs, or perhaps just a little bit of brokenness.
It's time to do better. This patch series allows us to do better.

Assuming that people think this patch series looks OK, we'll have to
figure out the right way to land it. The panel patches and i2c-hid
patches will go through very different trees and so either we'll need
an Ack from one side or the other or someone to create a tag for the
other tree to pull in. This will _probably_ require the true drm-misc
maintainers to get involved, not a lowly committer. ;-)

Version 2 of this patch series doesn't change too much. At a high level:
* I added all the forgotten "static" to functions.
* I've hopefully made the bindings better.
* I've integrated into fw_devlink.
* I cleaned up a few descriptions / comments.

This still needs someone to say that the idea looks OK or to suggest
an alternative that solves the problems. ;-)

Changes in v2:
- Move the description to the generic touchscreen.yaml.
- Update the desc to make it clearer it's only for integrated devices.
- Add even more text to the commit message.
- A few comment cleanups.
- ("Add a devlink for panel followers") new for v2.
- i2c_hid_core_initial_power_up() is now static.
- i2c_hid_core_panel_prepared() and ..._unpreparing() are now static.
- ihid_core_panel_prepare_work() is now static.
- Improve documentation for smp_wmb().

Douglas Anderson (10):
  dt-bindings: HID: i2c-hid: Add "panel" property to i2c-hid backed
    touchscreens
  drm/panel: Check for already prepared/enabled in drm_panel
  drm/panel: Add a way for other devices to follow panel state
  of: property: fw_devlink: Add a devlink for panel followers
  HID: i2c-hid: Switch to SYSTEM_SLEEP_PM_OPS()
  HID: i2c-hid: Rearrange probe() to power things up later
  HID: i2c-hid: Make suspend and resume into helper functions
  HID: i2c-hid: Support being a panel follower
  HID: i2c-hid: Do panel follower work on the system_wq
  arm64: dts: qcom: sc7180: Link trogdor touchscreens to the panels

 .../bindings/input/elan,ekth6915.yaml         |   5 +
 .../bindings/input/goodix,gt7375p.yaml        |   5 +
 .../bindings/input/hid-over-i2c.yaml          |   2 +
 .../input/touchscreen/touchscreen.yaml        |   7 +
 .../boot/dts/qcom/sc7180-trogdor-coachz.dtsi  |   1 +
 .../dts/qcom/sc7180-trogdor-homestar.dtsi     |   1 +
 .../boot/dts/qcom/sc7180-trogdor-lazor.dtsi   |   1 +
 .../boot/dts/qcom/sc7180-trogdor-pompom.dtsi  |   1 +
 .../qcom/sc7180-trogdor-quackingstick.dtsi    |   1 +
 .../dts/qcom/sc7180-trogdor-wormdingler.dtsi  |   1 +
 drivers/gpu/drm/drm_panel.c                   | 196 +++++++++-
 drivers/hid/i2c-hid/i2c-hid-core.c            | 338 +++++++++++++-----
 drivers/of/property.c                         |   2 +
 include/drm/drm_panel.h                       |  89 +++++
 14 files changed, 555 insertions(+), 95 deletions(-)

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2.41.0.162.gfafddb0af9-goog