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+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,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 at 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;
+};
Devices need to report various identifiers in the ACPI tables. Rather than hard-coding these in drivers it is typically better to put them in the device tree. Add a binding file to describe this. Signed-off-by: Simon Glass <sjg at chromium.org> --- Changes in v8: None Changes in v7: None Changes in v5: None Changes in v4: - Put 'interrupts-extended' property on one line - Rename acpi-probed to linux,probed - Note that linux,probed is an out-of-tree feature Changes in v3: - Drop mention of PRIC - Rename acpi,desc to acpi,ddn - Correct description of acpi,probed - Drop hid-descr-addr - Just add the device.txt binding file in this patch - Change the example to ELAN - Add a pointer to information about acpi,compatible Changes in v2: - Fix definition of HID - Infer hid-over-i2c CID value - Add the hid-over-i2c binding document doc/device-tree-bindings/device.txt | 36 +++++++++++++++++++++++++++++ 1 file changed, 36 insertions(+) create mode 100644 doc/device-tree-bindings/device.txt