linux_dsm_epyc7002/Documentation/devicetree/bindings/display/atmel/hlcdc-dc.txt
Peter Rosin 2e7c04aec8 dt-bindings: display: atmel: optional video-interface of endpoints
With bus-type/bus-width properties in the endpoint nodes, the video-
interface of the connection can be specified for cases where the
heuristic fails to select the correct output mode. This can happen
e.g. if not all RGB pins are routed on the PCB; the driver has no
way of knowing this, and needs to be told explicitly.

This is critical for the devices that have the "conflicting output
formats" issue (SAM9N12, SAM9X5, SAMA5D3), since the most significant
RGB bits move around depending on the selected output mode. For
devices that do not have the "conflicting output formats" issue
(SAMA5D2, SAMA5D4), this is completely irrelevant.

Acked-by: Boris Brezillon <boris.brezillon@bootlin.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Reviewed-by: Jacopo Mondi <jacopo+renesas@jmondi.org>
Signed-off-by: Peter Rosin <peda@axentia.se>
Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180825085620.10566-3-peda@axentia.se
2018-08-27 21:21:16 +02:00

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Device-Tree bindings for Atmel's HLCDC (High LCD Controller) DRM driver
The Atmel HLCDC Display Controller is subdevice of the HLCDC MFD device.
See ../../mfd/atmel-hlcdc.txt for more details.
Required properties:
- compatible: value should be "atmel,hlcdc-display-controller"
- pinctrl-names: the pin control state names. Should contain "default".
- pinctrl-0: should contain the default pinctrl states.
- #address-cells: should be set to 1.
- #size-cells: should be set to 0.
Required children nodes:
Children nodes are encoding available output ports and their connections
to external devices using the OF graph reprensentation (see ../graph.txt).
At least one port node is required.
Optional properties in grandchild nodes:
Any endpoint grandchild node may specify a desired video interface
according to ../../media/video-interfaces.txt, specifically
- bus-width: recognized values are <12>, <16>, <18> and <24>, and
override any output mode selection heuristic, forcing "rgb444",
"rgb565", "rgb666" and "rgb888" respectively.
Example:
hlcdc: hlcdc@f0030000 {
compatible = "atmel,sama5d3-hlcdc";
reg = <0xf0030000 0x2000>;
interrupts = <36 IRQ_TYPE_LEVEL_HIGH 0>;
clocks = <&lcdc_clk>, <&lcdck>, <&clk32k>;
clock-names = "periph_clk","sys_clk", "slow_clk";
hlcdc-display-controller {
compatible = "atmel,hlcdc-display-controller";
pinctrl-names = "default";
pinctrl-0 = <&pinctrl_lcd_base &pinctrl_lcd_rgb888>;
#address-cells = <1>;
#size-cells = <0>;
port@0 {
#address-cells = <1>;
#size-cells = <0>;
reg = <0>;
hlcdc_panel_output: endpoint@0 {
reg = <0>;
remote-endpoint = <&panel_input>;
};
};
};
hlcdc_pwm: hlcdc-pwm {
compatible = "atmel,hlcdc-pwm";
pinctrl-names = "default";
pinctrl-0 = <&pinctrl_lcd_pwm>;
#pwm-cells = <3>;
};
};
Example 2: With a video interface override to force rgb565; as above
but with these changes/additions:
&hlcdc {
hlcdc-display-controller {
pinctrl-names = "default";
pinctrl-0 = <&pinctrl_lcd_base &pinctrl_lcd_rgb565>;
port@0 {
hlcdc_panel_output: endpoint@0 {
bus-width = <16>;
};
};
};
};