8cb2cbae45
In order to make GPIO ACPI library stricter prepare users of gpiod_get_index() to correctly behave when there no mapping is provided by firmware. Here we add explicit mapping between _CRS GpioIo() resources and their names used in the driver. Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
27 lines
1.2 KiB
Text
27 lines
1.2 KiB
Text
Intel INT3496 ACPI device extcon driver documentation
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The Intel INT3496 ACPI device extcon driver is a driver for ACPI
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devices with an acpi-id of INT3496, such as found for example on
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Intel Baytrail and Cherrytrail tablets.
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This ACPI device describes how the OS can read the id-pin of the devices'
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USB-otg port, as well as how it optionally can enable Vbus output on the
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otg port and how it can optionally control the muxing of the data pins
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between an USB host and an USB peripheral controller.
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The ACPI devices exposes this functionality by returning an array with up
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to 3 gpio descriptors from its ACPI _CRS (Current Resource Settings) call:
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Index 0: The input gpio for the id-pin, this is always present and valid
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Index 1: The output gpio for enabling Vbus output from the device to the otg
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port, write 1 to enable the Vbus output (this gpio descriptor may
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be absent or invalid)
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Index 2: The output gpio for muxing of the data pins between the USB host and
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the USB peripheral controller, write 1 to mux to the peripheral
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controller
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There is a mapping between indices and GPIO connection IDs as follows
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id index 0
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vbus index 1
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mux index 2
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