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@chromium.org ---
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
diff --git a/doc/device-tree-bindings/device.txt b/doc/device-tree-bindings/device.txt new file mode 100644 index 00000000000..27bd3978d98 --- /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; +};