extcon: int3496: Add Intel INT3496 ACPI device extcon driver
Add an extcon driver for USB OTG ports controlled by an Intel INT3496
ACPI device (e.g. Baytrail, Cherrytrail devices).
Signed-off-by: David Cohen <david.a.cohen@intel.com>
[hdgoede@redhat.com: Port to current kernel, cleanup, submit upstream]
[hdgoede@redhat.com: Add Documentation/extcon/intel-int3496.txt]
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
diff --git a/Documentation/extcon/intel-int3496.txt b/Documentation/extcon/intel-int3496.txt
new file mode 100644
index 0000000..af0b366
--- /dev/null
+++ b/Documentation/extcon/intel-int3496.txt
@@ -0,0 +1,22 @@
+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