28 lines
1.2 KiB
Plaintext
28 lines
1.2 KiB
Plaintext
|
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
|