Device Tree overlay for GT9110 touch driver on Raspberry Pi

README.md

GT9110 DTS for RPi

This is a Device Tree (DT) overlay for Goodix GT9110 touch controllers connected to Raspberry Pi via I2C on GPIO pins.

To use it, download the .dts file below or create one yourself and store it somewhere where you can find it. From the same directory run the following command to compile it:

sudo dtc -I dts -O dtb -o /boot/overlays/gt9110.dtbo GT9110_overlay.dts 

This will compile the 'GT9110_overlay.dts' file into 'gt9110.dtbo' and store it under /boot/overlays.

Next you need to enable it in the /boot/config.txt file using the following:

dtoverlay=gt9110

** Also do not forget to enable the I2C interface on your board:

dtparam=i2c_arm=on

Pinout Table

This is how the pins are currently connected:

Pin	GT9110	RPi GPIO	Pin
1	SDA	GPIO 2	3
2	SCL	GPIO 3	5
3	RST	GPIO 4	7
4	INT	GPIO 27	13
5	VDD	3V3	1
6	GND	Ground	9

---

For more information about Device Trees, visit here: https://www.raspberrypi.org/documentation/configuration/device-tree.md

For a quick guide to all DT overlays used in Raspberry Pi, visit below: https://github.com/raspberrypi/firmware/blob/master/boot/overlays/README

GT9110_overlay.dts

// Device tree overlay for Goodix GT9110 touch controller
// connected to Raspberry Pi via I2C on GPIO pins. 
/dts-v1/;
/plugin/;

/ {
        compatible = "brcm,bcm2835", "brcm,bcm2836", "brcm,bcm2708", "brcm,bcm2709";

        fragment@0 {
                target = <&gpio>;                        // Overlay for GPIO pins, using standard 'gpio' node
                __overlay__ {
                        goodix_pins: goodix_pins {       // create overlay labeled "goodix_pins"
                                brcm,pins = <27 4>;      // use GPIO_27(pin 13), GPIO_4(pin 7)
                                brcm,function = <0 0>;   // set pins as Output
                                brcm,pull = <2 2>;       // enable internal pull-up resistors
                        };
                };
        };

        fragment@1 {
                target = <&i2c1>;                        // Overlay for I2C pins, using the 'i2c1' node
                __overlay__ {                            
                        #address-cells = <1>;
                        #size-cells = <0>;
                        status = "okay";                 // device is enabled

                        gt9110: gt9110@14 {                   // set GT9110 with i2c address 0x14
                                compatible = "goodix,gt9110"; // using 'goodix' kernel device driver
                                reg = <0x14>;                 // I2C address (needs to match above)
                                pinctrl-names = "default";    // default pin configuration
                                pinctrl-0 = <&goodix_pins>;   // assign overlay to pin control
                                interrupt-parent = <&gpio>;   // assign interrupt rutines
                                interrupts = <27 2>;          // high-to-low edge triggered
                                irq-gpios = <&gpio 27 0>;     // set Interupt pin on GPIO 27
                                reset-gpios = <&gpio 4 0>;    // set Reset pin on GPIO 4
                        };
                };
        };
};