[PATCH v8 4/4] ARM: dts: stm32: support display on stm32f746-disco board

[Dario Binacchi <dario.binacchi@amarulasolutions.com>]

Add support to Rocktech RK043FN48H display on stm32f746-disco board.

Signed-off-by: Dario Binacchi <dario.binacchi@amarulasolutions.com>
Reviewed-by: Raphaël Gallais-Pou <raphael.gallais-pou@foss.st.com>

---

Changes in v8:
- Add the 'power-supply' property to panel-rgb node.
- Move backlight and panel-rgb nodes after the vcc-3v3 node.

Changes in v7:
- Add 'Reviewed-by' tags I forgot in v6.
  https://lore.kernel.org/linux-arm-kernel/20230629083726.84910-1-dario.binacchi@amarulasolutions.com/T/
- Add 'Reviewed-by' tag I forgot in v6.
  https://lore.kernel.org/linux-arm-kernel/20230629083726.84910-1-dario.binacchi@amarulasolutions.com/T/

Changes in v6:
- Remove dma nodes from stm32f746-disco.dts, they are not used by LTDC,
  so there is no need to enable them.

Changes in v5:
I am confident that framebuffer sizing is a real requirement for STM32 boards,
but I need some time to understand if and how to introduce this functionality.
Therefore, I drop the following patches to allow the series to be fully merged:
 - [4/6] dt-bindings: display: stm32-ltdc: add optional st,fb-bpp property
 - [5/6] ARM: dts: stm32: set framebuffer bit depth on stm32f746-disco
 - [6/6] drm/stm: set framebuffer bit depth through DTS property

Changes in v4:
- Use DTS property instead of module parameter to set the framebuffer bit depth.

Changes in v3:
- drop [4/6] dt-bindings: display: simple: add Rocktech RK043FN48H
  Applied to https://anongit.freedesktop.org/git/drm/drm-misc.git (drm-misc-next):
  https://cgit.freedesktop.org/drm/drm-misc/commit/?id=c42a37a27c777d63961dd634a30f7c887949491a
- drop [5/6] drm/panel: simple: add support for Rocktech RK043FN48H panel
  Applied to https://anongit.freedesktop.org/git/drm/drm-misc.git (drm-misc-next)
  https://cgit.freedesktop.org/drm/drm-misc/commit/?id=13cdd12a9f934158f4ec817cf048fcb4384aa9dc

 arch/arm/boot/dts/st/stm32f746-disco.dts | 44 ++++++++++++++++++++++++
 1 file changed, 44 insertions(+)

diff --git a/arch/arm/boot/dts/st/stm32f746-disco.dts b/arch/arm/boot/dts/st/stm32f746-disco.dts
index 4e785039ba5a..bf91f6b1c0f3 100644
--- a/arch/arm/boot/dts/st/stm32f746-disco.dts
+++ b/arch/arm/boot/dts/st/stm32f746-disco.dts
@@ -60,6 +60,19 @@ memory@c0000000 {
 		reg = <0xC0000000 0x800000>;
 	};
 
+	reserved-memory {
+		#address-cells = <1>;
+		#size-cells = <1>;
+		ranges;
+
+		linux,cma {
+			compatible = "shared-dma-pool";
+			no-map;
+			size = <0x80000>;
+			linux,dma-default;
+		};
+	};
+
 	aliases {
 		serial0 = &usart1;
 	};
@@ -85,6 +98,25 @@ vcc_3v3: vcc-3v3 {
 		regulator-min-microvolt = <3300000>;
 		regulator-max-microvolt = <3300000>;
 	};
+
+	backlight: backlight {
+		compatible = "gpio-backlight";
+		gpios = <&gpiok 3 GPIO_ACTIVE_HIGH>;
+		status = "okay";
+	};
+
+	panel_rgb: panel-rgb {
+		compatible = "rocktech,rk043fn48h";
+		power-supply = <&vcc_3v3>;
+		backlight = <&backlight>;
+		enable-gpios = <&gpioi 12 GPIO_ACTIVE_HIGH>;
+		status = "okay";
+		port {
+			panel_in_rgb: endpoint {
+				remote-endpoint = <&ltdc_out_rgb>;
+			};
+		};
+	};
 };
 
 &clk_hse {
@@ -99,6 +131,18 @@ &i2c1 {
 	status = "okay";
 };
 
+&ltdc {
+	pinctrl-0 = <&ltdc_pins_a>;
+	pinctrl-names = "default";
+	status = "okay";
+
+	port {
+		ltdc_out_rgb: endpoint {
+			remote-endpoint = <&panel_in_rgb>;
+		};
+	};
+};
+
 &sdio1 {
 	status = "okay";
 	vmmc-supply = <&vcc_3v3>;
-- 
2.34.1