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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>
37 lines
1.3 KiB
Plaintext
37 lines
1.3 KiB
Plaintext
Devices
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=======
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Device bindings are described by their own individual binding files.
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U-Boot provides for some optional properties which are documented here. See
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also hid-over-i2c.txt which describes HID devices. See also
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Documentation/firmware-guide/acpi/enumeration.rst in the Linux kernel for
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the acpi,compatible property.
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- acpi,has-power-resource : (boolean) true if this device has a power resource.
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This causes an ACPI PowerResource to be written containing the properties
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provided by this binding, to describe how to handle powering the device up
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and down using GPIOs
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- acpi,compatible : compatible string to report
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- acpi,ddn : Contains the string to use as the _DDN (DOS (Disk Operating
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System) Device Name)
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- acpi,hid : Contains the string to use as the HID (Hardware ID)
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identifier _HID
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- acpi,uid : _UID value for device
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- linux,probed : Tells U-Boot to add 'linux,probed' to the ACPI tables so that
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Linux will only load the driver if the device can be detected (e.g. on I2C
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bus). Note that this is an out-of-tree Linux feature.
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Example
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-------
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elan_touchscreen: elan-touchscreen@10 {
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compatible = "i2c-chip";
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reg = <0x10>;
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acpi,hid = "ELAN0001";
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acpi,ddn = "ELAN Touchscreen";
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interrupts-extended = <&acpi_gpe GPIO_21_IRQ IRQ_TYPE_EDGE_FALLING>;
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linux,probed;
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};
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