usb: Add driver for UCSI

USB Type-C Connector System Software Interface (UCSI) is
specification that defines the registers and data structures
that can be used to control USB Type-C ports on a system.
UCSI is used on several Intel Broxton SoC based platforms.
Things that UCSI can be used to control include at least USB
Data Role swapping, Power Role swapping and controlling of
Alternate Modes on top of providing general details about
the port and the partners that are attached to it.

The initial purpose of the UCSI driver is to make sure USB
is in host mode on desktop and server systems that are USB
dual role capable, and provide UCSI interface.

The goal is to integrate the driver later to an USB Type-C
framework for Linux kernel, and at the same time add support
for more extensive USB Type-C port control that UCSI offers,
for example data role swapping, power role swapping,
Alternate Mode control etc.

The UCSI specification is public can be obtained from here:
http://www.intel.com/content/www/us/en/io/universal-serial-bus/usb-type-c-ucsi-spec.html

Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 26 insertions, 0 deletions

diff --git a/drivers/usb/misc/Kconfig b/drivers/usb/misc/Kconfig
index f7a7fc21be8a..e9e5ae521fa6 100644
--- a/drivers/usb/misc/Kconfig
+++ b/drivers/usb/misc/Kconfig
@@ -268,3 +268,29 @@ config USB_CHAOSKEY
 
 	  To compile this driver as a module, choose M here: the
 	  module will be called chaoskey.
+
+config UCSI
+	tristate "USB Type-C Connector System Software Interface driver"
+	depends on ACPI
+	help
+	  UCSI driver is meant to be used as a convenience tool for desktop and
+	  server systems that are not equipped to handle USB in device mode. It
+	  will always select USB host role for the USB Type-C ports on systems
+	  that provide UCSI interface.
+
+	  USB Type-C Connector System Software Interface (UCSI) is a
+	  specification for an interface that allows the Operating System to
+	  control the USB Type-C ports on a system. Things the need controlling
+	  include the USB Data Role (host or device), and when USB Power
+	  Delivery is supported, the Power Role (source or sink). With USB
+	  Type-C connectors, when two dual role capable devices are attached
+	  together, the data role is selected randomly. Therefore it is
+	  important to give the OS a way to select the role. Otherwise the user
+	  would have to unplug and replug in order in order to attempt to swap
+	  the data and power roles.
+
+	  The UCSI specification can be downloaded from:
+	  http://www.intel.com/content/www/us/en/io/universal-serial-bus/usb-type-c-ucsi-spec.html
+
+	  To compile the driver as a module, choose M here: the module will be
+	  called ucsi.