ANX7688 is a typec port controller that also converts HDMI to DP. ANX7688 is found on Acer Chromebook R13 (elm) and on Pine64 PinePhone.
On Acer Chromebook R13 (elm), the device is powered-up and controller by the Embedded Controller. Therefore its operation is transparent to the SoC. It is used in elm only as a display bridge driver. The bridge driver only reads some values using i2c and use them to implement the mode_fixup cb.
On v5 we added the full dt-binding of the generic Analogix anx7688 device. The problem is that for elm, most of the fields are not needed since the anx7688 sits behind the EC. After a discussion on v5 (see [1]) we decided to go back to the original approach and send the dt binding as specific to the elm. So in this version we rename the device to cros_ec_anx7688 and use the compatible 'google,cros-ec-anx7688'.
[1] https://patchwork.kernel.org/project/dri-devel/patch/20210305124351.15079-3-...
Changes since v5: * treat the device as a specific combination of an ANX7688 behind the EC and call it 'cros-ec-anx7688'
Changes since v4: In v4 of this set, the device was added as an 'mfd' device and an additional 'bridge' device for the HDMI-DP conversion, see [2].
[2] https://lkml.org/lkml/2020/3/18/64
Dafna Hirschfeld (1): dt-bindings: display: add google,cros-ec-anx7688.yaml
Enric Balletbo i Serra (1): drm/bridge: Add ChromeOS EC ANX7688 bridge driver support
.../bridge/google,cros-ec-anx7688.yaml | 82 ++++++++ drivers/gpu/drm/bridge/Kconfig | 12 ++ drivers/gpu/drm/bridge/Makefile | 1 + drivers/gpu/drm/bridge/cros-ec-anx7688.c | 191 ++++++++++++++++++ 4 files changed, 286 insertions(+) create mode 100644 Documentation/devicetree/bindings/display/bridge/google,cros-ec-anx7688.yaml create mode 100644 drivers/gpu/drm/bridge/cros-ec-anx7688.c