Raspberry Pi Forums

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/dts-v1/;
/plugin/;
/ {
	compatible = "brcm,bcm2835";
	i2c_frag: fragment@0 {
		target = <&i2c_csi_dsi>;
		__overlay__ {
			#address-cells = <1>;
			#size-cells = <0>;
			status = "okay";
			gt911: gt911@5d {
				compatible = "goodix,gt911";
				reg = <0x5d>;
				touchscreen-x-mm = <90>;
				touchscreen-y-mm = <151>;
				reset-gpios = <&gpio 5 1>;	// 1 means GPIO_ACTIVE_LOW
				irq-gpios = <&gpio 6 0>;
				interrupt-parent = <&gpio>;
				interrupts = <6 2>;	// 2 = IRQ_TYPE_EDGE_FALLING
				touchscreen-swapped-x-y=<1>;
				touchscreen-inverted-y=<1>;
			};
		};
	};	
	
	dsi_frag: fragment@1 {
		target = <&dsi1>;
		__overlay__ {
			#address-cells = <1>;
			#size-cells = <0>;
			status = "okay";			
			port {
				dsi_out: endpoint {
					remote-endpoint = <&dsi_panel_in>;
				};
			}; 
			
			panel_disp: panel_disp@0 {
				reg = <0>;
				// Loads a modified version of the panel-ilitek-ili9806e driver
				compatible = "densitron,dmt050wvnmcmi-1a";
				
				// This is an unconnected dummy gpio, the display is reset by the touch controller init
				reset-gpios = <&gpio 8 1>;	// 1 means GPIO_ACTIVE_LOW
				
				port {
					dsi_panel_in: endpoint {
						remote-endpoint = <&dsi_out>;
					};
				};
			};
		};
	};
};

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ctx->reset_gpio = devm_gpiod_get(dev, "reset", GPIOD_OUT_LOW);

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ctx->reset_gpio = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_LOW);

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[...]
panel_disp: panel_disp@0 {
	// Ensure touchscreen is probed first to perform reset
	parent = < &gt911 >;
[...]

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static int ili9806e_dsi_probe(struct mipi_dsi_device *dsi)
{
	struct device *dev = &dsi->dev;
	
	struct device_node * parent = of_parse_phandle(dev->of_node, "parent", 0);
	if (parent)
	{
		struct device *parent_dev;
		parent_dev = bus_find_device_by_of_node(&i2c_bus_type, parent);

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static int ili9806e_dsi_probe(struct mipi_dsi_device *dsi)
{
	struct device *dev = &dsi->dev;
	
	struct device_node * parent = of_parse_phandle(dev->of_node, "parent", 0);
	if (parent)
	{
		struct i2c_client * parent_i2c = of_find_i2c_device_by_node(parent);
		if (parent_i2c)
		{
			void * data = dev_get_drvdata(&parent_i2c->dev);
			put_device(&parent_i2c->dev);
			
			if (!data)
			{
				printk(KERN_INFO "ili9806e parent i2c not ready, deferring");
				return -EPROBE_DEFER;
			}			
		}
[...]		

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/dts-v1/;
/plugin/;
#include <dt-bindings/gpio/gpio-fsm.h>
#define DISP_RESET GF_SW(0)
#define TS_RESET GF_SW(1)
#define SHARED_RESET GF_OP(0) // GPIO7
/{
	compatible = "brcm,bcm2835";
	fragment@0 {
		target-path = "/";
		__overlay__ {
			disp_reset: disp-reset {
				compatible = "rpi,gpio-fsm";
				debug = <0>;
				gpio-controller;
				#gpio-cells = <2>;
				num-swgpios = <2>;
				gpio-line-names = "disp_reset", "ts_reset";
				output-gpios = <&gpio 7 1>; // SHARED_RESET
				shutdown-timeout-ms = <2000>;
				idle {
					start_state;
					set = <SHARED_RESET 0>;
					reset_0 = <DISP_RESET 1>;
					reset_1 = <TS_RESET 1>;
				};
				reset_0 {
					set = <SHARED_RESET 1>;
					unreset_0 = <DISP_RESET 0>;
				};
				unreset_0 {
					set = <SHARED_RESET 0>;
					skipreset_0a = <DISP_RESET 1>;
				};
				skipreset_0a {
					skipreset_0b = <TS_RESET 1>;
				};
				skipreset_0b {
					idle = <TS_RESET 0>;
				};
				reset_1 {
					set = <SHARED_RESET 1>;
					unreset_1 = <TS_RESET 0>;
				};
				unreset_1 {
					set = <SHARED_RESET 0>;
					skipreset_1a = <TS_RESET 1>;
				};
				skipreset_1a {
					skipreset_1b = <DISP_RESET 1>;
				};
				skipreset_1b {
					idle = <DISP_RESET 0>;
				};
			};
		};
	};
	__overrides__ {
		fsm_debug = <&disp_reset>,"debug:0";
	};
};