[v8,0/2] Add support of Lontium lt8912 MIPI to HDMI bridge

Message

Adrien Grassein March 23, 2021, 6:14 p.m. UTC

Hi,
this patch set adds the support of the Lontium lt8912 MIPI to HDMI
bridge in the kernel.

It's only support the video part, not the audio part yet
since I don't have the datasheet of this component.
I get the current i2c configuration from Digi and
Boundary drivers.
Developed using the DB_DSIHD board from BoundaryDevices.

Update in v2
  - Use standard data-lanes instead of a custom prop;
  - Use hdmi-connector node.

Update in v3
  - Fix indentation;
  - Implement missing bridge functions;
  - Add some comments.

Update in v4
  - Fix bridge ops;
  - Fix i2c error detection.

Update in v5
  - Fix lt8912 name (lt8912b instead of lt8912);
  - Implement HPD via a workaround. In fact I don't have the datasheet
    of this component yet so I can't say if the configuration of the
registers is correct or if I have an HW issue on my board. So, I choose
to implement a fake version of HPD using a workqueue and polling the
status regularly.

Update in v6
  - Fix a warning found by "kernel test robot"

Update in v7
  - Fix HPD logic (via an HW emulation);
  - HPD from chip is still not working.

Update in v8
  - Remove HPD logic (will be added later when HW bug qill be fixed).

Thanks,

Adrien Grassein (2):
  dt-bindings: display: bridge: Add documentation for LT8912B
  drm/bridge: Introduce LT8912B DSI to HDMI bridge

 .../display/bridge/lontium,lt8912b.yaml       | 102 +++
 MAINTAINERS                                   |   6 +
 drivers/gpu/drm/bridge/Kconfig                |  14 +
 drivers/gpu/drm/bridge/Makefile               |   1 +
 drivers/gpu/drm/bridge/lontium-lt8912b.c      | 765 ++++++++++++++++++
 5 files changed, 888 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/display/bridge/lontium,lt8912b.yaml
 create mode 100644 drivers/gpu/drm/bridge/lontium-lt8912b.c