Devicetree overlay to enable the ILI9225 display on the Raspberry Pi 4

ili9225-on-pi4-spi1.dtso

// SPDX-License-Identifier: BSD-3-Clause
/* Copyright (c) 2026 David Lechner <david@lechnology.com> */

/*
 * Devicetree overlay to enable the ILI9225 display on the Raspberry Pi 4.
 *
 * Wiring:
 *
 * ILI9225 Panel   | Raspberry Pi 4
 * Pin Name        | Pin# | Function
 * ----------------+------+--------------------------
 * VCC             | 1    | 3.3V
 * GND             | 9    | GND
 * GND             | x    | Not connected
 * NC              | x    | Not connected
 * NC              | x    | Not connected
 * LED             | 33   | PWM 0, ch 1 (GPIO13)
 * CLK             | 40   | SPI1 SCLK (GPIO21)
 * SPI             | 38   | SPI1 MOSI (GPIO20)
 * RS              | 37   | GPIO26
 * RST             | 35   | GPIO19
 * CS              | 36   | GPIO16
 */

/dts-v1/;
/plugin/;

#include <dt-bindings/gpio/gpio.h>

&{/} {
	ili9225_bl: backlight_pwm_1 {
		compatible = "pwm-backlight";

		pinctrl-names = "default";
		pinctrl-0 = <&pwm0_1_gpio13>;

		pwms = <&pwm 1 200000 0>;
		brightness-levels = <0 6 8 12 16 24 32 40 48 64 96 128 160 192 224 255>;
		default-brightness-level = <10>;
	};
};

&gpio {
	spi1_mosi_sclk_gpio20: spi1-mosi-sclk-gpio20 {
		pins-spi {
			pins = "gpio20", "gpio21";
			function = "alt4";
		};
	};
};

&spi1 {
	#address-cells = <1>;
	#size-cells = <0>;

	pinctrl-names = "default";
	pinctrl-0 = <&spi1_mosi_sclk_gpio20>;

	/*
	 * spi-bcm2835aux supports only one reliable native chip select.
	 * Expose CS2 on GPIO16 using cs-gpios.
	 */
	cs-gpios = <0>, <0>, <&gpio 16 GPIO_ACTIVE_LOW>;
	status = "okay";

	panel@2 {
		compatible = "vot,v220hf01a-t", "ilitek,ili9225";
		reg = <2>;
		spi-max-frequency = <12000000>;
		rs-gpios = <&gpio 26 GPIO_ACTIVE_HIGH>;
		reset-gpios = <&gpio 19 GPIO_ACTIVE_HIGH>;
		backlight = <&ili9225_bl>;
	};
};