From fa04cef6443eab008b99f6439ec8a3b9939253b4 Mon Sep 17 00:00:00 2001 From: Simon Glass Date: Sun, 26 Apr 2020 09:19:45 -0600 Subject: [PATCH] acpi: Add a binding for ACPI settings in the device tree 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 --- doc/device-tree-bindings/device.txt | 36 +++++++++++++++++++++++++++++ 1 file changed, 36 insertions(+) create mode 100644 doc/device-tree-bindings/device.txt diff --git a/doc/device-tree-bindings/device.txt b/doc/device-tree-bindings/device.txt new file mode 100644 index 0000000000..27bd3978d9 --- /dev/null +++ b/doc/device-tree-bindings/device.txt @@ -0,0 +1,36 @@ +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@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; +}; -- 2.25.1