[U-Boot] [PATCH v2 07/19] tegra: fdt: Add LCD definitions for Tegra

Simon Glass
2012-06-13T16:19:43Z

Add LCD definitions and also a proposed binding for LCD displays.

The PWFM is in progress on the device-tree-discuss list, so only a
very basic binding is offered here.

I am not sure if it is better to have the lcd within the display
controller as with i2c/spi, or a separate node. From a hardware point
of view the LCD is certainly connected to the display controller, so
perhaps this version makes most sense. We could have a stand-alone
top-level lcd node with a phandle pointing to the display controller,
but these doesn't seem to be an obvious advantage to that approach.

Signed-off-by: Simon Glass <sjg@chromium.org>
---
Changes in v2:
- Add nvidia prefix to device tree properties

arch/arm/dts/tegra20.dtsi | 25 +++++++
doc/device-tree-bindings/video/nvidia-video.txt | 88 +++++++++++++++++++++++
2 files changed, 113 insertions(+), 0 deletions(-)
create mode 100644 doc/device-tree-bindings/video/nvidia-video.txt

diff --git a/arch/arm/dts/tegra20.dtsi b/arch/arm/dts/tegra20.dtsi
index f95be58..4e59e9b 100644
--- a/arch/arm/dts/tegra20.dtsi
+++ b/arch/arm/dts/tegra20.dtsi
@@ -204,4 +204,29 @@
compatible = "nvidia,tegra20-kbc";
reg = <0x7000e200 0x0078>;
};
+
+ pwfm0: pwm at 7000a000 {
+ compatible = "nvidia,tegra20-pwfm";
+ reg = <0x7000a000 0x4>;
+ };
+
+ pwfm1: pwm at 7000a010 {
+ compatible = "nvidia,tegra20-pwfm";
+ reg = <0x7000a010 0x4>;
+ };
+
+ pwfm2: pwm at 7000a020 {
+ compatible = "nvidia,tegra20-pwfm";
+ reg = <0x7000a020 0x4>;
+ };
+
+ pwfm3: pwm at 7000a030 {
+ compatible = "nvidia,tegra20-pwfm";
+ reg = <0x7000a030 0x4>;
+ };
+
+ display1: display at 0x54200000 {
+ compatible = "nvidia,tegra20-display";
+ reg = <0x54200000 0x40000>;
+ };
};
diff --git a/doc/device-tree-bindings/video/nvidia-video.txt b/doc/device-tree-bindings/video/nvidia-video.txt
new file mode 100644
index 0000000..2e1b999
--- /dev/null
+++ b/doc/device-tree-bindings/video/nvidia-video.txt
@@ -0,0 +1,88 @@
+LCD Display
+-----------
+
+(there isn't yet a generic binding in Linux, so this describes what is in
+U-Boot)
+
+The device node for a display device is as described in the document
+"Open Firmware Recommended Practice : Universal Serial Bus" with the
+following modifications and additions :
+
+Required properties :
+ - compatible : Should be "nvidia,tegra20-display"
+ - nvidia,pwfm: phandle of PWFM to use for backlight
+
+Note: This is just a phande and provides no information, nor a backlight
+node. The PWM is still under discussion I think:
+ http://patchwork.ozlabs.org/patch/132386/
+
+We don't support any parameters as yet - the setting is hard-coded.
+
+ - nvidia,width: width of display in pixels
+ - nvidia,height: height of display in pixels
+ - nvidia,bits-per-pixel: number of bits per pixel (depth)
+ - nvidia,pixel-clock : Pixel clock in Hz
+ - nvidia,horiz-timing; horizontal timing: ref_to_sync, sync_width. back_porch,
+ front_porch
+ - nvidia,vert-timing; vertical timing: ref_to_sync, sync_width. back_porch,
+ front_porch
+
+This node should sit inside its controller.
+
+
+Nvidia Tegra2x Display Controller
+---------------------------------
+
+The device node for a NAND flash controller is as described in the document
+"Open Firmware Recommended Practice : Universal Serial Bus" with the
+following modifications and additions :
+
+Required properties:
+ - compatible: should be "tegra20-display"
+ - panel-timings: 4 cells containing required timings in ms:
+ * delay between panel_vdd-rise and data-rise
+ * delay between data-rise and backlight_vdd-rise
+ * delay between backlight_vdd and pwm-rise
+ * delay between pwm-rise and backlight_en-rise
+
+(should we use us here, or perhaps call it panel-timings-ms?)
+
+Optional properties:
+ - nvidia,frame-buffer: address of frame buffer (if omitted it will be
+ calculated)
+ - This may be useful to share an address between U-Boot and Linux and
+ avoid boot-time corruption / flicker
+
+Optional GPIO properies all have (phandle, GPIO number, flags):
+ - nvidia,backlight-enable-gpios: backlight enable GPIO
+ - nvidia,lvds-shutdown-gpios: LVDS power shutdown GPIO
+ - nvidia,backlight-vdd-gpios: backlight power GPIO
+ - nvidia,panel-vdd-gpios: panel power GPIO
+
+(Perhap use polariy bit so that lvds-shutdown becomes lvds-enable?)
+
+I have put these into the display controller since I don't think they are
+generic enough to go in the lcd node.
+
+Example:
+
+display at 0x54200000 {
+ nvidia,pwfm = <&pwfm2>;
+ nvidia,frame-buffer = <0x2f680000>;
+ nvidia,backlight-enable-gpios = <&gpio 28 0>; /* PD4 */
+ nvidia,lvds-shutdown-gpios = <&gpio 10 0>; /* PB2 */
+ nvidia,backlight-vdd-gpios = <&gpio 176 0>; /* PW0 */
+ nvidia,panel-vdd-gpios = <&gpio 22 0>; /* PC6 */
+ nvidia,panel-timings = <4 203 17 15>;
+
+ lcd {
+ compatible = "nvidia,lcd";
+ nvidia,width = <1366>;
+ nvidia,height = <768>;
+ nvidia,bits-per-pixel = <16>;
+ nvidia,pixel-clock = <70600000>;
+
+ nvidia,horiz-timing = <11 58 58 58>;
+ nvidia,vert-timing = <1 4 4 4>;
+ };
+};
--
1.7.7.3