Touchscreen hardware components

Applicable for

STM32MP13x lines, STM32MP15x lines, STM32MP25x lines

---

1. Article purpose

The purpose of this article is to:

• list the touchscreen hardware components that might be integrated in the different boards
• link these components to the corresponding software framework(s)
• point to the datasheet(s) of these components
• explain, when necessary, how to configure these components

2. Software frameworks

Domain	Peripheral	Software components			Comment
		OP-TEE	Linux	STM32Cube
Visual and Inputs	Goodix GT9147		Inputs framework		Touchscreen input driver
Visual and Inputs	FocalTech FT6236		Inputs framework		Touchscreen input driver
Visual and Inputs	Ilitek ILI251x		Inputs framework		Touchscreen input driver

3. Goodix GT9147

The Goodix GT9147 is a single-layer multi-touch capacitive touch controller driver.

For details and the datasheet please contact the GT9147 driver provider.

Information

This touchscreen controller driver can be found on some STM32MP15 Evaluation boards.

3.1. Linux driver

Bindings: Documentation/devicetree/bindings/input/touchscreen/goodix.yaml

Sources: drivers/input/touchscreen/goodix.c

Click here to show the example

Devicetree example: arch/arm/boot/dts/stm32mp157d-ev1.dts

...
&dsi {
	#address-cells = <1>;
	#size-cells = <0>;
	status = "okay";

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

		port@0 {
			reg = <0>;
			dsi_in: endpoint {
				remote-endpoint = <&ltdc_ep0_out>;
			};
		};

		port@1 {
			reg = <1>;
			dsi_out: endpoint {
				remote-endpoint = <&dsi_panel_in>;
			};
		};
	};

	panel_dsi: panel-dsi@0 {
		compatible = "raydium,rm68200";
		reg = <0>;
		reset-gpios = <&gpiof 15 GPIO_ACTIVE_LOW>;
		backlight = <&panel_backlight>;
		power-supply = <&v3v3>;
		status = "okay";

		port {
			dsi_panel_in: endpoint {
				remote-endpoint = <&dsi_out>;
			};
		};
	};
};


&i2c2 {
...
	stmfx: stmfx@42 {
		compatible = "st,stmfx-0300";
		reg = <0x42>;
		interrupts = <8 IRQ_TYPE_EDGE_RISING>;
		interrupt-parent = <&gpioi>;
		vdd-supply = <&v3v3>;

		stmfx_pinctrl: pinctrl {
			compatible = "st,stmfx-0300-pinctrl";
			gpio-controller;
			#gpio-cells = <2>;
			interrupt-controller;
			#interrupt-cells = <2>;
			gpio-ranges = <&stmfx_pinctrl 0 0 24>;

			goodix_pins: goodix {
				pins = "gpio14";
				bias-pull-down;
			};

			joystick_pins: joystick-pins {
				pins = "gpio0", "gpio1", "gpio2", "gpio3", "gpio4";
				bias-pull-down;
			};
		};
	};

	gt9147: goodix-ts@5d {
		compatible = "goodix,gt9147";
		reg = <0x5d>;
		panel = <&panel_dsi>;
		pinctrl-0 = <&goodix_pins>;
		pinctrl-names = "default";
		AVDD28-supply = <&v3v3>;
		VDDIO-supply = <&v3v3>;
		status = "okay";

		interrupts = <14 IRQ_TYPE_EDGE_RISING>;
		interrupt-parent = <&stmfx_pinctrl>;
	};
};

4. FocalTech FT6236

The FocalTech FT6236 is a self-capacitive touch panel controller driver.

For details and the datasheet please contact the FT6236 driver provider.

Information

This touchscreen controller driver can be found on some STM32MP15 Discovery kits.

4.1. Linux driver

Bindings: Documentation/devicetree/bindings/input/touchscreen/edt-ft5x06.yaml

Sources: drivers/input/touchscreen/edt-ft5x06.c

Click here to show the example

Devicetree example: arch/arm/boot/dts/stm32mp157f-dk2.dts

&dsi {
	status = "okay";

	ports {
		port@0 {
			reg = <0>;
			dsi_in: endpoint {
				remote-endpoint = <&ltdc_ep1_out>;
			};
		};

		port@1 {
			reg = <1>;
			dsi_out: endpoint {
				remote-endpoint = <&panel_in>;
			};
		};
	};

	panel_otm8009a: panel-otm8009a@0 {
		compatible = "orisetech,otm8009a";
		reg = <0>;
		reset-gpios = <&gpioe 4 GPIO_ACTIVE_LOW>;
		power-supply = <&v3v3>;
		status = "okay";

		port {
			panel_in: endpoint {
				remote-endpoint = <&dsi_out>;
			};
		};
	};
};

&i2c1 {
	touchscreen@2a {
		compatible = "focaltech,ft6236";
		reg = <0x2a>;
		interrupts = <2 2>;
		interrupt-parent = <&gpiof>;
		interrupt-controller;
		touchscreen-size-x = <480>;
		touchscreen-size-y = <800>;
		panel = <&panel_otm8009a>;
		vcc-supply = <&v3v3>;
		iovcc-supply = <&v3v3>;
		status = "okay";
	};
	touchscreen@38 {
		compatible = "focaltech,ft6236";
		reg = <0x38>;
		interrupts = <2 2>;
		interrupt-parent = <&gpiof>;
		interrupt-controller;
		touchscreen-size-x = <480>;
		touchscreen-size-y = <800>;
		panel = <&panel_otm8009a>;
		vcc-supply = <&v3v3>;
		iovcc-supply = <&v3v3>;
		status = "okay";
	};
};

&ltdc {
	status = "okay";

	port {
		ltdc_ep1_out: endpoint@1 {
			reg = <1>;
			remote-endpoint = <&dsi_in>;
		};
	};
};

5. Ilitek ILI251x

The Ilitek ILI251x is a multi-touch capacitive touch controller driver.

For details and the datasheet please contact the ILI251x driver provider.

Information

This touchscreen controller driver can be found on some STM32MP257F EV1 Evaluation boards.

5.1. Linux driver

Bindings: Documentation/devicetree/bindings/input/touchscreen/ilitek_ts_i2c.yaml

Sources: drivers/input/touchscreen/ilitek_ts_i2c.c

Click here to show the example

Devicetree example: arch/arm64/boot/dts/st/stm32mp257f-ev1.dts

...
/ {
...
	panel_dsi_backlight: panel-dsi-backlight {
		compatible = "gpio-backlight";
		gpios = <&gpioi 5 GPIO_ACTIVE_LOW>;
		default-on;
		default-brightness-level = <0>;
		status = "disabled";
	};

	panel_lvds: panel-lvds {
		compatible = "edt,etml0700z9ndha", "panel-lvds";
		enable-gpios = <&gpiog 15 GPIO_ACTIVE_HIGH>;
		backlight = <&panel_lvds_backlight>;
		status = "okay";

		width-mm = <156>;
		height-mm = <92>;
		data-mapping = "vesa-24";

		panel-timing {
			clock-frequency = <54000000>;
			hactive = <1024>;
			vactive = <600>;
			hfront-porch = <150>;
			hback-porch = <150>;
			hsync-len = <21>;
			vfront-porch = <24>;
			vback-porch = <24>;
			vsync-len = <21>;
		};

		port {
			lvds_panel_in: endpoint {
				remote-endpoint = <&lvds_out0>;
			};
		};
	};

	panel_lvds_backlight: panel-lvds-backlight {
		compatible = "gpio-backlight";
		gpios = <&gpioi 5 GPIO_ACTIVE_HIGH>;
		default-on;
		default-brightness-level = <0>;
		status = "okay";
	};
...
};

...
&i2c2 {
...
	ili2511: ili2511@41 {
		compatible = "ilitek,ili251x";
		reg = <0x41>;
		interrupt-parent = <&gpioi>;
		interrupts = <13 IRQ_TYPE_EDGE_FALLING>;
		reset-gpios = <&gpiog 14 GPIO_ACTIVE_LOW>;
		status = "okay";
	};
};
...
&ltdc {
	rotation-memory = <&ltdc_sec_rotation>;
	status = "okay";

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

		ltdc_ep0_out: endpoint@0 {
			reg = <0>;
			remote-endpoint = <&dsi_in>;
		};

		ltdc_ep1_out: endpoint@1 {
			reg = <1>;
			remote-endpoint = <&lvds_in>;
		};
	};
};

&lvds {
	status = "okay";

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

		port@0 {
			reg = <0>;
			lvds_in: endpoint {
				remote-endpoint = <&ltdc_ep1_out>;
			};
		};

		port@1 {
			reg = <1>;
			lvds_out0: endpoint {
				remote-endpoint = <&lvds_panel_in>;
			};
		};
	};
};

Open portable trusted execution environment

Linux^® is a registered trademark of Linus Torvalds.

General-purpose input/output (A realization of open ended transmission between devices on an embedded level. These pins available on a processor can be programmed to be used to either accept input or provide output to external devices depending on user desires and applications requirements.)

Linux^® is a registered trademark of Linus Torvalds.