Overlay for NanoPi Neo with ILI9341; Shared SPI with two CS; Allwinner H3

[G-EDM Developer]

Hi,

 

after having a hard time getting the ILI9341 touchscreen working with the NanoPi Neo (Allwinner H3)  it seems to work now.

 

To have more GPIOs available for other stuff the touch and display need to share SPI0

 

I would like to upload it to github because there is basically nothing out of the box available but I'm a total noob with NanoPi, Armbian and overlays so maybe someone could look at it.

 

root@nanopineo:~# uname -a
Linux nanopineo 5.15.93-sunxi #23.02.2 SMP Fri Feb 17 00:00:00 UTC 2023 armv7l armv7l armv7l GNU/Linux

 

 

This is the wiring between ILI9341 and NanoPi Neo:

 

 

/*
   3.3v <-->  VCC & LED
   GND  <-->  GND
   PC2  <-->  SCK       & T_CLK
   PC1  <-->  SDO<MISO> & T_DO
   PC0  <-->  SDI<MOSI> & T_DIN
   PA1  <-->  DC
   PG8  <-->  RESET
   PC3  <-->  CS
   PA3  <-->  T_CS
   PG9  <-->  T_IRG
 */

 

 

 

This is the overlay:

 

/dts-v1/;
/plugin/;

/ {
	compatible = "allwinner,sun8i-h3";

	fragment@0 {
		target = <&pio>;
		__overlay__ {
			spi0_cs1: spi0_cs1 {
				pins = "PC3"; 
				function = "gpio_out";
				output-high;
			};

			spi1_cs1: spi1_cs1 {
				pins = "PA3"; 
				function = "gpio_out";
				output-high;
			};

			opiz_display_pins: opiz_display_pins {
                pins = "PA1", "PG8", "PA6";
                function = "gpio_out";
            };

            ads7846_pins: ads7846_pins {
                pins = "PG9";
                function = "irq";
            };


		};
	};

	fragment@1 {
		target = <&spi1>;
		__overlay__ {
			pinctrl-names = "default", "default";
			pinctrl-1 = <&spi1_cs1>;
			cs-gpios = <0>, <&pio 0 3 0>; /* PA3 */
		};
	};

	fragment@2 {
		target = <&spi0>;
		__overlay__ {
			#address-cells = <1>;
			#size-cells = <0>;
			status = "okay";

			pinctrl-names = "default", "default";
			cs-gpios= <&pio 2 3 0>, <&pio 0 3 1>;

			opizdisplay: opiz-display@0 {
			    pinctrl-1 = <&spi0_cs1>;
				reg = <0>; /* Chip Select 0 */
                compatible = "ilitek,ili9341";
				spi-max-frequency = <1000000>;
				status = "okay";
                pinctrl-names = "default";
                pinctrl-0 = <&opiz_display_pins>;
                rotate = <90>;
                bgr = <0>;
                fps = <33>;
                buswidth = <8>;
                dc-gpios = <&pio 0 1 0>;      /* PIN_22  GPIOA1 > */
                reset-gpios = <&pio 6 8 1 >; /*    GPIOG8> */
                /*led-gpios=<&pio 0 6 0>;        PIN_12  GPIOA6 > */
                debug=<4>;                        
			};

			ads7846: ads7846@1 {
				reg = <1>; /* Chip Select 1 */
				compatible = "ti,ads7846";
				spi-max-frequency = <1000000>;
				status = "okay";
                pinctrl-2=<&spi1_cs1 &spi1_cs1>;
                pinctrl-names = "default";
                pinctrl-3 = <&ads7846_pins>;
                interrupt-parent = <&pio>;
                interrupts = <6 9 2>; /* PG9 IRQ_TYPE_EDGE_FALLING */
                pendown-gpio = <&pio 6 9 0>; /* PG9 */
                /* driver defaults, optional */
                ti,x-min = /bits/ 16 <0>;
                ti,y-min = /bits/ 16 <0>;
                ti,x-max = /bits/ 16 <0x0FFF>;
                ti,y-max = /bits/ 16 <0x0FFF>;
                ti,pressure-min = /bits/ 16 <0>;
                ti,pressure-max = /bits/ 16 <0xFFFF>;
                ti,x-plate-ohms = /bits/ 16 <400>;
			};

		};

	};

};

 

 

 

 

 

This is the /boot/armbianEnv.txt

 

verbosity=1
bootlogo=false
console=serial
disp_mode=1920x1080p60
overlay_prefix=sun8i-h3
overlays=usbhost1 usbhost2 spi0
param_spidev_spi_bus=0
param_spidev_spi_cs=1
param_spidev_spi_cs=0
rootdev=UUID=XYZ-LONG-UUID-IS-LONG
rootfstype=ext4
user_overlays=ili-touch-spi
usbstoragequirks=0x2537:0x1066:u,0x2537:0x1068:u

 

 

 

After connecting via ssh and starting evtest it shows this when touched ( not sure if it shows the correct coordinates yet )

 

Event: time 1682020476.763295, -------------- SYN_REPORT ------------
Event: time 1682020476.775286, type 3 (EV_ABS), code 0 (ABS_X), value 535
Event: time 1682020476.775286, type 3 (EV_ABS), code 1 (ABS_Y), value 3553
Event: time 1682020476.775286, type 3 (EV_ABS), code 24 (ABS_PRESSURE), value 65169

 

 

 

 

So it looks like everything is working but to be on the safe side I would like to wait until some pro reviewed the overlay.

 

Thanks.

[G-EDM Developer]

The line

"user_overlays=ili-touch-spi"

is generated automatically after adding the overlay with:

armbian-add-overlay /path/to/ili-touch-spi.dts

 

So the name will be the name the file was named.

[G-EDM Developer]

Update:

changed

spi-max-frequency = <1000000>;

 

to:

spi-max-frequency = <2000000>;

 

for display and touch.

[schunckt]

Does that really work?

It looks like the overlay mixes SPI0 and SPI1 which are two different separated SPI controllers inside the SOC

(of course the NEO only has SPI0 on it's pins)

 

Beside that the dts uses PA6 which isn't wired. What's its purpose?

 

 

 

T.