Texas Instruments OMAP Display Subsystem
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========================================
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Generic Description
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-------------------
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This document is a generic description of the OMAP Display Subsystem bindings.
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Binding details for each OMAP SoC version are described in respective binding
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documentation.
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The OMAP Display Subsystem (DSS) hardware consists of DSS Core, DISPC module and
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a number of encoder modules. All DSS versions contain DSS Core and DISPC, but
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the encoder modules vary.
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The DSS Core is the parent of the other DSS modules, and manages clock routing,
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integration to the SoC, etc.
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DISPC is the display controller, which reads pixels from the memory and outputs
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a RGB pixel stream to encoders.
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The encoder modules encode the received RGB pixel stream to a video output like
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HDMI, MIPI DPI, etc.
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Video Ports
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-----------
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The DSS Core and the encoders have video port outputs. The structure of the
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video ports is described in Documentation/devicetree/bindings/graph.txt,
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and the properties for the ports and endpoints for each encoder are
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described in the SoC's DSS binding documentation.
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The video ports are used to describe the connections to external hardware, like
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panels or external encoders.
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Aliases
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-------
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The board dts file may define aliases for displays to assign "displayX" style
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name for each display. If no aliases are defined, a semi-random number is used
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for the display.
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Example
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-------
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A shortened example of the DSS description for OMAP4, with non-relevant parts
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removed, defined in omap4.dtsi:
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dss: dss@58000000 {
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compatible = "ti,omap4-dss";
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reg = <0x58000000 0x80>;
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status = "disabled";
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ti,hwmods = "dss_core";
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clocks = <&dss_dss_clk>;
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clock-names = "fck";
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#address-cells = <1>;
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#size-cells = <1>;
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ranges;
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dispc@58001000 {
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compatible = "ti,omap4-dispc";
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reg = <0x58001000 0x1000>;
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interrupts = <GIC_SPI 25 IRQ_TYPE_LEVEL_HIGH>;
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ti,hwmods = "dss_dispc";
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clocks = <&dss_dss_clk>;
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clock-names = "fck";
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};
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hdmi: encoder@58006000 {
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compatible = "ti,omap4-hdmi";
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reg = <0x58006000 0x200>,
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<0x58006200 0x100>,
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<0x58006300 0x100>,
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<0x58006400 0x1000>;
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reg-names = "wp", "pll", "phy", "core";
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interrupts = <GIC_SPI 101 IRQ_TYPE_LEVEL_HIGH>;
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status = "disabled";
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ti,hwmods = "dss_hdmi";
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clocks = <&dss_48mhz_clk>, <&dss_sys_clk>;
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clock-names = "fck", "sys_clk";
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};
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};
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A shortened example of the board description for OMAP4 Panda board, defined in
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omap4-panda.dts.
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The Panda board has a DVI and a HDMI connector, and the board contains a TFP410
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chip (MIPI DPI to DVI encoder) and a TPD12S015 chip (HDMI ESD protection & level
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shifter). The video pipelines for the connectors are formed as follows:
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DSS Core --(MIPI DPI)--> TFP410 --(DVI)--> DVI Connector
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OMAP HDMI --(HDMI)--> TPD12S015 --(HDMI)--> HDMI Connector
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/ {
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aliases {
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display0 = &dvi0;
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display1 = &hdmi0;
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};
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tfp410: encoder@0 {
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compatible = "ti,tfp410";
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gpios = <&gpio1 0 GPIO_ACTIVE_LOW>; /* 0, power-down */
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pinctrl-names = "default";
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pinctrl-0 = <&tfp410_pins>;
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ports {
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#address-cells = <1>;
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#size-cells = <0>;
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port@0 {
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reg = <0>;
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tfp410_in: endpoint@0 {
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remote-endpoint = <&dpi_out>;
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};
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};
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port@1 {
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reg = <1>;
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tfp410_out: endpoint@0 {
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remote-endpoint = <&dvi_connector_in>;
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};
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};
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};
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};
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dvi0: connector@0 {
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compatible = "dvi-connector";
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label = "dvi";
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i2c-bus = <&i2c3>;
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port {
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dvi_connector_in: endpoint {
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remote-endpoint = <&tfp410_out>;
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};
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};
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};
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tpd12s015: encoder@1 {
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compatible = "ti,tpd12s015";
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pinctrl-names = "default";
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pinctrl-0 = <&tpd12s015_pins>;
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gpios = <&gpio2 28 GPIO_ACTIVE_HIGH>, /* 60, CT CP HPD */
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<&gpio2 9 GPIO_ACTIVE_HIGH>, /* 41, LS OE */
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<&gpio2 31 GPIO_ACTIVE_HIGH>; /* 63, HPD */
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ports {
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#address-cells = <1>;
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#size-cells = <0>;
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port@0 {
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reg = <0>;
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tpd12s015_in: endpoint@0 {
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remote-endpoint = <&hdmi_out>;
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};
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};
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port@1 {
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reg = <1>;
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tpd12s015_out: endpoint@0 {
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remote-endpoint = <&hdmi_connector_in>;
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};
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};
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};
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};
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hdmi0: connector@1 {
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compatible = "hdmi-connector";
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label = "hdmi";
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port {
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hdmi_connector_in: endpoint {
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remote-endpoint = <&tpd12s015_out>;
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};
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};
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};
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};
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&dss {
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status = "ok";
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pinctrl-names = "default";
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pinctrl-0 = <&dss_dpi_pins>;
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port {
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dpi_out: endpoint {
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remote-endpoint = <&tfp410_in>;
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data-lines = <24>;
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};
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};
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};
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&hdmi {
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status = "ok";
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vdda-supply = <&vdac>;
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pinctrl-names = "default";
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pinctrl-0 = <&dss_hdmi_pins>;
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port {
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hdmi_out: endpoint {
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remote-endpoint = <&tpd12s015_in>;
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};
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};
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};
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