Add device trees for MHS3.5 SPI devices

Signed-off-by: Mel <mel@rnrd.eu>

1 files changed, 74 insertions, 0 deletions

diff --git a/dts/mhs35-overlay.dts b/dts/mhs35-overlay.dts
new file mode 100644
index 0000000..e30e596
--- /dev/null
+++ b/dts/mhs35-overlay.dts
@@ -0,0 +1,74 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * device tree overlay for a goodtft mhs-3.5 raspberry pi spi display.
+ *
+ * for touch, see `./mhs35-touch-overlay.dts`!
+ *
+ * Copyright (c) 2026 Mel G. <mel@rnrd.eu>
+ */
+
+/dts-v1/;
+/plugin/;
+
+/ {
+	compatible = "brcm,bcm2711";
+
+	fragment@0 {
+		target = <&spi0>;
+
+		__overlay__ {
+			status = "okay";
+
+			spidev@0 {
+				status = "disabled";
+			};
+		};
+	};
+
+	fragment@1 {
+		target = <&gpio>;
+
+		__overlay__ {
+			mhs35_pins: mhs35_pins@0 {
+				brcm,pins = <25 24>; // reset, dc
+				brcm,function = <0 0>;
+			};
+		};
+	};
+
+	fragment@2 {
+		target = <&spi0>;
+
+		__overlay__ {
+			#address-cells = <1>;
+			#size-cells = <0>;
+
+			mhs35: mhs35@0 {
+				compatible = "goodtft,mhs35";
+				reg = <0>;
+				pinctrl-names = "default";
+				pinctrl-0 = <&mhs35_pins>;
+
+				// very conservative default that works pretty well,
+				// though is quite slow (you can see the screen update!)
+				// according to spec, should go upto 125mhz.
+				spi-max-frequency = <8000000>;
+
+				// orientation relative to a raspberry pi 4:
+				// 0 = landscape, usb/ethernet ports on left
+				// 180 = landscape, ports on right
+				// 90 = portrait, ports on top
+				// 270 portrait, ports on bottom
+				rotation = <180>;
+
+				reset-gpios = <&gpio 25 1>;
+				dc-gpios = <&gpio 24 0>;
+			};
+		};
+	};
+
+	__overrides__ {
+		speed =    <&mhs35>,"spi-max-frequency:0";
+		rotation = <&mhs35>,"rotation:0";
+	};
+};