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1 | Intel INT3496 ACPI device extcon driver documentation |
2 | ----------------------------------------------------- | |
3 | ||
4 | The Intel INT3496 ACPI device extcon driver is a driver for ACPI | |
5 | devices with an acpi-id of INT3496, such as found for example on | |
6 | Intel Baytrail and Cherrytrail tablets. | |
7 | ||
8 | This ACPI device describes how the OS can read the id-pin of the devices' | |
9 | USB-otg port, as well as how it optionally can enable Vbus output on the | |
10 | otg port and how it can optionally control the muxing of the data pins | |
11 | between an USB host and an USB peripheral controller. | |
12 | ||
13 | The ACPI devices exposes this functionality by returning an array with up | |
14 | to 3 gpio descriptors from its ACPI _CRS (Current Resource Settings) call: | |
15 | ||
16 | Index 0: The input gpio for the id-pin, this is always present and valid | |
17 | Index 1: The output gpio for enabling Vbus output from the device to the otg | |
18 | port, write 1 to enable the Vbus output (this gpio descriptor may | |
19 | be absent or invalid) | |
20 | Index 2: The output gpio for muxing of the data pins between the USB host and | |
21 | the USB peripheral controller, write 1 to mux to the peripheral | |
22 | controller | |
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23 | |
24 | There is a mapping between indices and GPIO connection IDs as follows | |
25 | id index 0 | |
26 | vbus index 1 | |
27 | mux index 2 |