The backlight level of an eDP panel can be controlled through the AUX channel using DPCD registers of the panel. The capability for the Source device to adjust backlight characteristics within the panel, using the Sink device DPCD registers is indicated by the TCON_BACKLIGHT_ADJUSTMENT_CAPABLE bit in the EDP_GENERAL_CAPABILITY_1 register (DPCD Address 701h, bit0). In this configuration, the eDP TCON receives the backlight level information from the host, through the AUX channel. The changes in this patch series do the following: - Add drm_dp_aux_backlight_ APIs to support backlight control using DPCD registers on the DisplayPort AUX channel. The current version only supports backlight brightness control by the EDP_BACKLIGHT_BRIGHTNESS_MSB/LSB registers (DPCD Addresses 722h-723h). - Add support for backlight control of the eDP panel connected to the ti-sn65dsi86 bridge. Rajeev Nandan (3): drm/dp: Add DisplayPort aux backlight control support dt-bindings: drm/bridge: ti-sn65dsi86: Document use-aux-backlight drm/bridge: ti-sn65dsi86: Add DisplayPort aux backlight support .../bindings/display/bridge/ti,sn65dsi86.yaml | 8 + drivers/gpu/drm/Kconfig | 8 + drivers/gpu/drm/Makefile | 1 + drivers/gpu/drm/bridge/Kconfig | 1 + drivers/gpu/drm/bridge/ti-sn65dsi86.c | 26 +++ drivers/gpu/drm/drm_dp_aux_backlight.c | 191 +++++++++++++++++++++ include/drm/drm_dp_aux_backlight.h | 29 ++++ 7 files changed, 264 insertions(+) create mode 100644 drivers/gpu/drm/drm_dp_aux_backlight.c create mode 100644 include/drm/drm_dp_aux_backlight.h -- 2.7.4
