Display Controller
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(there isn't yet a generic binding in Linux, so this describes what is in
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U-Boot, and may change based on Linux activity)
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The device node for a display device is as described in the document
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"Open Firmware Recommended Practice : Universal Serial Bus" with the
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following modifications and additions :
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Required properties :
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- compatible : Should be "nvidia,tegra20-dc"
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Required subnode 'rgb' is as follows:
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Required properties (rgb) :
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- nvidia,panel : phandle of LCD panel information
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The panel node describes the panel itself. This has the properties listed in
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displaymode.txt as well as:
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Required properties (panel) :
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- nvidia,bits-per-pixel: number of bits per pixel (depth)
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- nvidia,pwm : pwm to use to set display contrast (see tegra20-pwm.txt)
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- nvidia,panel-timings: 4 cells containing required timings in ms:
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* delay before asserting panel_vdd
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* delay between panel_vdd-rise and data-rise
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* delay between data-rise and backlight_vdd-rise
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* delay between backlight_vdd and pwm-rise
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* delay between pwm-rise and backlight_en-rise
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Optional GPIO properies all have (phandle, GPIO number, flags):
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- nvidia,backlight-enable-gpios: backlight enable GPIO
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- nvidia,lvds-shutdown-gpios: LVDS power shutdown GPIO
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- nvidia,backlight-vdd-gpios: backlight power GPIO
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- nvidia,panel-vdd-gpios: panel power GPIO
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Example:
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host1x {
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compatible = "nvidia,tegra20-host1x", "simple-bus";
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reg = <0x50000000 0x00024000>;
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interrupts = <0 65 0x04 /* mpcore syncpt */
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0 67 0x04>; /* mpcore general */
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#address-cells = <1>;
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#size-cells = <1>;
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status = "okay";
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ranges = <0x54000000 0x54000000 0x04000000>;
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dc@54200000 {
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compatible = "nvidia,tegra20-dc";
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reg = <0x54200000 0x00040000>;
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interrupts = <0 73 0x04>;
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status = "okay";
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rgb {
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status = "okay";
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nvidia,panel = <&lcd_panel>;
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};
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};
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};
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lcd_panel: panel {
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/* Seaboard has 1366x768 */
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clock = <70600000>;
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xres = <1366>;
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yres = <768>;
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left-margin = <58>;
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right-margin = <58>;
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hsync-len = <58>;
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lower-margin = <4>;
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upper-margin = <4>;
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vsync-len = <4>;
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hsync-active-high;
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nvidia,bits-per-pixel = <16>;
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nvidia,pwm = <&pwm 2 0>;
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nvidia,backlight-enable-gpios = <&gpio 28 0>; /* PD4 */
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nvidia,lvds-shutdown-gpios = <&gpio 10 0>; /* PB2 */
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nvidia,backlight-vdd-gpios = <&gpio 176 0>; /* PW0 */
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nvidia,panel-vdd-gpios = <&gpio 22 0>; /* PC6 */
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nvidia,panel-timings = <400 4 203 17 15>;
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};
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