| David Cohen | 2f556bd | 2016-12-21 12:20:25 +0100 | [diff] [blame^] | 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 |