From: Rob Clark robdclark@chromium.org
It is not uncommon for devices to use one of several possible panels. The Lenovo Yoga C630 laptop is one such device. This patchset introduces an optional "panel-id" property which can be used by the firmware to find the correct panel node to enable. The second patch adds support in drm/of to automatically pick the enabled endpoint, to avoid adding the same logic in multiple bridges/drivers. The last patch uses this mechanism to enable display support for the Yoga C630.
An example usage:
boe_panel { compatible = "boe,nv133fhm-n61"; panel-id = <0xc4>; /* fw will change status to "Ok" if this panel is installed */ status = "disabled";
ports { port { boe_panel_in_edp: endpoint { remote-endpoint = <&sn65dsi86_out_boe>; }; }; }; };
ivo_panel { compatible = "ivo,m133nwf4-r0"; panel-id = <0xc5>; /* fw will change status to "Ok" if this panel is installed */ status = "disabled";
ports { port { ivo_panel_in_edp: endpoint { remote-endpoint = <&sn65dsi86_out_ivo>; }; }; }; };
sn65dsi86: bridge@2c { compatible = "ti,sn65dsi86";
ports { #address-cells = <1>; #size-cells = <0>;
port@0 { reg = <0>; sn65dsi86_in_a: endpoint { remote-endpoint = <&dsi0_out>; }; };
port@1 { reg = <1>;
sn65dsi86_out_boe: endpoint@c4 { remote-endpoint = <&boe_panel_in_edp>; };
sn65dsi86_out_ivo: endpoint@c5 { remote-endpoint = <&ivo_panel_in_edp>; }; }; }; };
This replaces an earlier proposal[1] to use chosen/panel-id to select the installed panel, in favor of adding support[2] to an EFI driver module (DtbLoader.efi) to find the installed panel, locate it in dtb via the 'panel-id' property, and update it's status to "Ok".
[1] https://patchwork.kernel.org/cover/11024613/ [2] https://github.com/robclark/edk2/commits/dtbloader
In this case, DtbLoader, which is somewhat generic (ie. this mechanism applies to all snapdragon based devices which orignally ship with windows), determines the panel-id of the installed panel from the UEFIDisplayInfo variable.
As I understand, a similar situation exists with the pine64 laptops. A similar scheme could be used to support this, by loading the panel-id from a u-boot variable.
In other cases (phones), a more device specific shim would be needed to determine the panel-id by reading some GPIOs, or some other more device- specific mechanism.
Bjorn Andersson (1): arm64: dts: qcom: c630: Enable display
Rob Clark (3): dt-bindings: display: panel: document panel-id drm/of: add support to find any enabled endpoint drm/bridge: ti-sn65dsi86: find any enabled endpoint
.../bindings/display/panel/panel-common.yaml | 26 +++ .../boot/dts/qcom/sdm850-lenovo-yoga-c630.dts | 165 ++++++++++++++++++ drivers/gpu/drm/bridge/ti-sn65dsi86.c | 2 +- drivers/gpu/drm/drm_of.c | 41 ++++- 4 files changed, 232 insertions(+), 2 deletions(-)