Commit 21a454fd authored by Maxime Ripard's avatar Maxime Ripard

drm: sun4i: Add DT bindings documentation

The display pipeline of the Allwinner A10 is involving several loosely
coupled components.

Add a documentation for the bindings.
Acked-by: default avatarRob Herring <robh@kernel.org>
Signed-off-by: default avatarMaxime Ripard <maxime.ripard@free-electrons.com>
parent 80588a86
Allwinner A10 Display Pipeline
==============================
The Allwinner A10 Display pipeline is composed of several components
that are going to be documented below:
TV Encoder
----------
The TV Encoder supports the composite and VGA output. It is one end of
the pipeline.
Required properties:
- compatible: value should be "allwinner,sun4i-a10-tv-encoder".
- reg: base address and size of memory-mapped region
- clocks: the clocks driving the TV encoder
- resets: phandle to the reset controller driving the encoder
- ports: A ports node with endpoint definitions as defined in
Documentation/devicetree/bindings/media/video-interfaces.txt. The
first port should be the input endpoint.
TCON
----
The TCON acts as a timing controller for RGB, LVDS and TV interfaces.
Required properties:
- compatible: value should be "allwinner,sun5i-a13-tcon".
- reg: base address and size of memory-mapped region
- interrupts: interrupt associated to this IP
- clocks: phandles to the clocks feeding the TCON. Three are needed:
- 'ahb': the interface clocks
- 'tcon-ch0': The clock driving the TCON channel 0
- 'tcon-ch1': The clock driving the TCON channel 1
- resets: phandles to the reset controllers driving the encoder
- "lcd": the reset line for the TCON channel 0
- clock-names: the clock names mentioned above
- reset-names: the reset names mentioned above
- clock-output-names: Name of the pixel clock created
- ports: A ports node with endpoint definitions as defined in
Documentation/devicetree/bindings/media/video-interfaces.txt. The
first port should be the input endpoint, the second one the output
The output should have two endpoints. The first is the block
connected to the TCON channel 0 (usually a panel or a bridge), the
second the block connected to the TCON channel 1 (usually the TV
encoder)
Display Engine Backend
----------------------
The display engine backend exposes layers and sprites to the
system.
Required properties:
- compatible: value must be one of:
* allwinner,sun5i-a13-display-backend
- reg: base address and size of the memory-mapped region.
- clocks: phandles to the clocks feeding the frontend and backend
* ahb: the backend interface clock
* mod: the backend module clock
* ram: the backend DRAM clock
- clock-names: the clock names mentioned above
- resets: phandles to the reset controllers driving the backend
- ports: A ports node with endpoint definitions as defined in
Documentation/devicetree/bindings/media/video-interfaces.txt. The
first port should be the input endpoints, the second one the output
Display Engine Frontend
-----------------------
The display engine frontend does formats conversion, scaling,
deinterlacing and color space conversion.
Required properties:
- compatible: value must be one of:
* allwinner,sun5i-a13-display-frontend
- reg: base address and size of the memory-mapped region.
- interrupts: interrupt associated to this IP
- clocks: phandles to the clocks feeding the frontend and backend
* ahb: the backend interface clock
* mod: the backend module clock
* ram: the backend DRAM clock
- clock-names: the clock names mentioned above
- resets: phandles to the reset controllers driving the backend
- ports: A ports node with endpoint definitions as defined in
Documentation/devicetree/bindings/media/video-interfaces.txt. The
first port should be the input endpoints, the second one the outputs
Display Engine Pipeline
-----------------------
The display engine pipeline (and its entry point, since it can be
either directly the backend or the frontend) is represented as an
extra node.
Required properties:
- compatible: value must be one of:
* allwinner,sun5i-a13-display-engine
- allwinner,pipelines: list of phandle to the display engine
frontends available.
Example:
panel: panel {
compatible = "olimex,lcd-olinuxino-43-ts";
#address-cells = <1>;
#size-cells = <0>;
port {
#address-cells = <1>;
#size-cells = <0>;
panel_input: endpoint {
remote-endpoint = <&tcon0_out_panel>;
};
};
};
tve0: tv-encoder@01c0a000 {
compatible = "allwinner,sun4i-a10-tv-encoder";
reg = <0x01c0a000 0x1000>;
clocks = <&ahb_gates 34>;
resets = <&tcon_ch0_clk 0>;
port {
#address-cells = <1>;
#size-cells = <0>;
tve0_in_tcon0: endpoint@0 {
reg = <0>;
remote-endpoint = <&tcon0_out_tve0>;
};
};
};
tcon0: lcd-controller@1c0c000 {
compatible = "allwinner,sun5i-a13-tcon";
reg = <0x01c0c000 0x1000>;
interrupts = <44>;
resets = <&tcon_ch0_clk 1>;
reset-names = "lcd";
clocks = <&ahb_gates 36>,
<&tcon_ch0_clk>,
<&tcon_ch1_clk>;
clock-names = "ahb",
"tcon-ch0",
"tcon-ch1";
clock-output-names = "tcon-pixel-clock";
ports {
#address-cells = <1>;
#size-cells = <0>;
tcon0_in: port@0 {
#address-cells = <1>;
#size-cells = <0>;
reg = <0>;
tcon0_in_be0: endpoint@0 {
reg = <0>;
remote-endpoint = <&be0_out_tcon0>;
};
};
tcon0_out: port@1 {
#address-cells = <1>;
#size-cells = <0>;
reg = <1>;
tcon0_out_panel: endpoint@0 {
reg = <0>;
remote-endpoint = <&panel_input>;
};
tcon0_out_tve0: endpoint@1 {
reg = <1>;
remote-endpoint = <&tve0_in_tcon0>;
};
};
};
};
fe0: display-frontend@1e00000 {
compatible = "allwinner,sun5i-a13-display-frontend";
reg = <0x01e00000 0x20000>;
interrupts = <47>;
clocks = <&ahb_gates 46>, <&de_fe_clk>,
<&dram_gates 25>;
clock-names = "ahb", "mod",
"ram";
resets = <&de_fe_clk>;
ports {
#address-cells = <1>;
#size-cells = <0>;
fe0_out: port@1 {
#address-cells = <1>;
#size-cells = <0>;
reg = <1>;
fe0_out_be0: endpoint {
remote-endpoint = <&be0_in_fe0>;
};
};
};
};
be0: display-backend@1e60000 {
compatible = "allwinner,sun5i-a13-display-backend";
reg = <0x01e60000 0x10000>;
clocks = <&ahb_gates 44>, <&de_be_clk>,
<&dram_gates 26>;
clock-names = "ahb", "mod",
"ram";
resets = <&de_be_clk>;
ports {
#address-cells = <1>;
#size-cells = <0>;
be0_in: port@0 {
#address-cells = <1>;
#size-cells = <0>;
reg = <0>;
be0_in_fe0: endpoint@0 {
reg = <0>;
remote-endpoint = <&fe0_out_be0>;
};
};
be0_out: port@1 {
#address-cells = <1>;
#size-cells = <0>;
reg = <1>;
be0_out_tcon0: endpoint@0 {
reg = <0>;
remote-endpoint = <&tcon0_in_be0>;
};
};
};
};
display-engine {
compatible = "allwinner,sun5i-a13-display-engine";
allwinner,pipelines = <&fe0>;
};
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