docs: extcon: convert it to ReST and move to ACPI dir

The intel-int3496.txt file is a documentation for an ACPI driver.

There's no reason to keep it on a separate directory.

So, instead of keeping it on some random location, move it
to a sub-directory inside the ACPI documentation dir,
renaming it to .rst.

Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Acked-by: Chanwoo Choi <cw00.choi@samsung.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

2 files changed, 34 insertions, 0 deletions

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 000000000000..5137ca834b54
--- /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
+        ======= =======
diff --git a/Documentation/firmware-guide/acpi/index.rst b/Documentation/firmware-guide/acpi/index.rst
index ae609eec4679..90c90d42d9ad 100644
--- a/Documentation/firmware-guide/acpi/index.rst
+++ b/Documentation/firmware-guide/acpi/index.rst
@@ -24,3 +24,4 @@ ACPI Support
    acpi-lid
    lpit
    video_extension
+   extcon-intel-int3496