Devices
=======

Device bindings are described by their own individual binding files.

U-Boot provides for some optional properties which are documented here. See
also hid-over-i2c.txt which describes HID devices. See also
Documentation/firmware-guide/acpi/enumeration.rst in the Linux kernel for
the acpi,compatible property.

 - acpi,has-power-resource : (boolean) true if this device has a power resource.
    This causes an ACPI PowerResource to be written containing the properties
    provided by this binding, to describe how to handle powering the device up
    and down using GPIOs
 - acpi,compatible : compatible string to report
 - acpi,ddn : Contains the string to use as the _DDN (DOS (Disk Operating
    System) Device Name)
 - acpi,hid : Contains the string to use as the HID (Hardware ID)
    identifier _HID
 - acpi,path : Specifies the full ACPI path for a device. This overrides the
    normal path built from the driver-model hierarchy
 - acpi,name : Provides the ACPI name for a device, which is a string consisting
   of four alphanumeric character (upper case)
 - acpi,uid : _UID value for device
 - linux,probed : Tells U-Boot to add 'linux,probed' to the ACPI tables so that
    Linux will only load the driver if the device can be detected (e.g. on I2C
    bus). Note that this is an out-of-tree Linux feature.


Example
-------

elan_touchscreen: elan-touchscreen@10 {
	compatible = "i2c-chip";
	reg = <0x10>;
	acpi,hid = "ELAN0001";
	acpi,ddn = "ELAN Touchscreen";
	interrupts-extended = <&acpi_gpe GPIO_21_IRQ IRQ_TYPE_EDGE_FALLING>;
	linux,probed;
};

pcie-a0@14,0 {
	reg = <0x0000a000 0 0 0 0>;
	acpi,name = "RP01";
	wifi: wifi {
		compatible = "intel,generic-wifi";
		acpi,ddn = "Intel WiFi";
		acpi,name = "WF00";
		interrupts-extended = <&acpi_gpe 0x3c 0>;
	};
};

p2sb: p2sb@d,0 {
	u-boot,dm-pre-reloc;
	reg = <0x02006810 0 0 0 0>;
	compatible = "intel,apl-p2sb";
	early-regs = <IOMAP_P2SB_BAR 0x100000>;
	pci,no-autoconfig;

	n {
		compatible = "intel,apl-pinctrl";
		u-boot,dm-pre-reloc;
		intel,p2sb-port-id = <PID_GPIO_N>;
		acpi,path = "\\_SB.GPO0";
		gpio_n: gpio-n {
			compatible = "intel,gpio";
			u-boot,dm-pre-reloc;
			gpio-controller;
			#gpio-cells = <2>;
			linux-name = "INT3452:00";
		};
	};