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Diffstat (limited to 'Documentation/firmware-guide/acpi/extcon-intel-int3496.rst')
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diff --git a/Documentation/firmware-guide/acpi/extcon-intel-int3496.rst b/Documentation/firmware-guide/acpi/extcon-intel-int3496.rst new file mode 100644 index 000000000..5137ca834 --- /dev/null +++ b/Documentation/firmware-guide/acpi/extcon-intel-int3496.rst @@ -0,0 +1,33 @@ +===================================================== +Intel INT3496 ACPI device extcon driver documentation +===================================================== + +The Intel INT3496 ACPI device extcon driver is a driver for ACPI +devices with an acpi-id of INT3496, such as found for example on +Intel Baytrail and Cherrytrail tablets. + +This ACPI device describes how the OS can read the id-pin of the devices' +USB-otg port, as well as how it optionally can enable Vbus output on the +otg port and how it can optionally control the muxing of the data pins +between an USB host and an USB peripheral controller. + +The ACPI devices exposes this functionality by returning an array with up +to 3 gpio descriptors from its ACPI _CRS (Current Resource Settings) call: + +======= ===================================================================== +Index 0 The input gpio for the id-pin, this is always present and valid +Index 1 The output gpio for enabling Vbus output from the device to the otg + port, write 1 to enable the Vbus output (this gpio descriptor may + be absent or invalid) +Index 2 The output gpio for muxing of the data pins between the USB host and + the USB peripheral controller, write 1 to mux to the peripheral + controller +======= ===================================================================== + +There is a mapping between indices and GPIO connection IDs as follows + + ======= ======= + id index 0 + vbus index 1 + mux index 2 + ======= ======= |