usb: USB Type-C connector class

The purpose of USB Type-C connector class is to provide
unified interface for the user space to get the status and
basic information about USB Type-C connectors on a system,
control over data role swapping, and when the port supports
USB Power Delivery, also control over power role swapping
and Alternate Modes.

Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-and-Tested-by: Felipe Balbi <felipe.balbi@linux.intel.com>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

2 files changed, 460 insertions, 0 deletions

diff --git a/Documentation/ABI/testing/sysfs-class-typec b/Documentation/ABI/testing/sysfs-class-typec
new file mode 100644
index 000000000000..d4a3d23eb09c
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-class-typec
@@ -0,0 +1,276 @@
+USB Type-C port devices (eg. /sys/class/typec/port0/)
+
+What:		/sys/class/typec/<port>/data_role
+Date:		April 2017
+Contact:	Heikki Krogerus <heikki.krogerus@linux.intel.com>
+Description:
+		The supported USB data roles. This attribute can be used for
+		requesting data role swapping on the port. Swapping is supported
+		as synchronous operation, so write(2) to the attribute will not
+		return until the operation has finished. The attribute is
+		notified about role changes so that poll(2) on the attribute
+		wakes up. Change on the role will also generate uevent
+		KOBJ_CHANGE on the port. The current role is show in brackets,
+		for example "[host] device" when DRP port is in host mode.
+
+		Valid values: host, device
+
+What:		/sys/class/typec/<port>/power_role
+Date:		April 2017
+Contact:	Heikki Krogerus <heikki.krogerus@linux.intel.com>
+Description:
+		The supported power roles. This attribute can be used to request
+		power role swap on the port when the port supports USB Power
+		Delivery. Swapping is supported as synchronous operation, so
+		write(2) to the attribute will not return until the operation
+		has finished. The attribute is notified about role changes so
+		that poll(2) on the attribute wakes up. Change on the role will
+		also generate uevent KOBJ_CHANGE. The current role is show in
+		brackets, for example "[source] sink" when in source mode.
+
+		Valid values: source, sink
+
+What:		/sys/class/typec/<port>/vconn_source
+Date:		April 2017
+Contact:	Heikki Krogerus <heikki.krogerus@linux.intel.com>
+Description:
+		Shows is the port VCONN Source. This attribute can be used to
+		request VCONN swap to change the VCONN Source during connection
+		when both the port and the partner support USB Power Delivery.
+		Swapping is supported as synchronous operation, so write(2) to
+		the attribute will not return until the operation has finished.
+		The attribute is notified about VCONN source changes so that
+		poll(2) on the attribute wakes up. Change on VCONN source also
+		generates uevent KOBJ_CHANGE.
+
+		Valid values:
+		- "no" when the port is not the VCONN Source
+		- "yes" when the port is the VCONN Source
+
+What:		/sys/class/typec/<port>/power_operation_mode
+Date:		April 2017
+Contact:	Heikki Krogerus <heikki.krogerus@linux.intel.com>
+Description:
+		Shows the current power operational mode the port is in. The
+		power operation mode means current level for VBUS. In case USB
+		Power Delivery communication is used for negotiating the levels,
+		power operation mode should show "usb_power_delivery".
+
+		Valid values:
+		- default
+		- 1.5A
+		- 3.0A
+		- usb_power_delivery
+
+What:		/sys/class/typec/<port>/preferred_role
+Date:		April 2017
+Contact:	Heikki Krogerus <heikki.krogerus@linux.intel.com>
+Description:
+		The user space can notify the driver about the preferred role.
+		It should be handled as enabling of Try.SRC or Try.SNK, as
+		defined in USB Type-C specification, in the port drivers. By
+		default the preferred role should come from the platform.
+
+		Valid values: source, sink, none (to remove preference)
+
+What:		/sys/class/typec/<port>/supported_accessory_modes
+Date:		April 2017
+Contact:	Heikki Krogerus <heikki.krogerus@linux.intel.com>
+Description:
+		Space separated list of accessory modes, defined in the USB
+		Type-C specification, the port supports.
+
+What:		/sys/class/typec/<port>/usb_power_delivery_revision
+Date:		April 2017
+Contact:	Heikki Krogerus <heikki.krogerus@linux.intel.com>
+Description:
+		Revision number of the supported USB Power Delivery
+		specification, or 0 when USB Power Delivery is not supported.
+
+What:		/sys/class/typec/<port>/usb_typec_revision
+Date:		April 2017
+Contact:	Heikki Krogerus <heikki.krogerus@linux.intel.com>
+Description:
+		Revision number of the supported USB Type-C specification.
+
+
+USB Type-C partner devices (eg. /sys/class/typec/port0-partner/)
+
+What:		/sys/class/typec/<port>-partner/accessory_mode
+Date:		April 2017
+Contact:	Heikki Krogerus <heikki.krogerus@linux.intel.com>
+Description:
+		Shows the Accessory Mode name when the partner is an Accessory.
+		The Accessory Modes are defined in USB Type-C Specification.
+
+What:		/sys/class/typec/<port>-partner/supports_usb_power_delivery
+Date:		April 2017
+Contact:	Heikki Krogerus <heikki.krogerus@linux.intel.com>
+Description:
+		Shows if the partner supports USB Power Delivery communication:
+		Valid values: yes, no
+
+What:		/sys/class/typec/<port>-partner>/identity/
+Date:		April 2017
+Contact:	Heikki Krogerus <heikki.krogerus@linux.intel.com>
+Description:
+		This directory appears only if the port device driver is capable
+		of showing the result of Discover Identity USB power delivery
+		command. That will not always be possible even when USB power
+		delivery is supported, for example when USB power delivery
+		communication for the port is mostly handled in firmware. If the
+		directory exists, it will have an attribute file for every VDO
+		in Discover Identity command result.
+
+What:		/sys/class/typec/<port>-partner/identity/id_header
+Date:		April 2017
+Contact:	Heikki Krogerus <heikki.krogerus@linux.intel.com>
+Description:
+		ID Header VDO part of Discover Identity command result. The
+		value will show 0 until Discover Identity command result becomes
+		available. The value can be polled.
+
+What:		/sys/class/typec/<port>-partner/identity/cert_stat
+Date:		April 2017
+Contact:	Heikki Krogerus <heikki.krogerus@linux.intel.com>
+Description:
+		Cert Stat VDO part of Discover Identity command result. The
+		value will show 0 until Discover Identity command result becomes
+		available. The value can be polled.
+
+What:		/sys/class/typec/<port>-partner/identity/product
+Date:		April 2017
+Contact:	Heikki Krogerus <heikki.krogerus@linux.intel.com>
+Description:
+		Product VDO part of Discover Identity command result. The value
+		will show 0 until Discover Identity command result becomes
+		available. The value can be polled.
+
+
+USB Type-C cable devices (eg. /sys/class/typec/port0-cable/)
+
+Note: Electronically Marked Cables will have a device also for one cable plug
+(eg. /sys/class/typec/port0-plug0). If the cable is active and has also SOP
+Double Prime controller (USB Power Deliver specification ch. 2.4) it will have
+second device also for the other plug. Both plugs may have alternate modes as
+described in USB Type-C and USB Power Delivery specifications.
+
+What:		/sys/class/typec/<port>-cable/type
+Date:		April 2017
+Contact:	Heikki Krogerus <heikki.krogerus@linux.intel.com>
+Description:
+		Shows if the cable is active.
+		Valid values: active, passive
+
+What:		/sys/class/typec/<port>-cable/plug_type
+Date:		April 2017
+Contact:	Heikki Krogerus <heikki.krogerus@linux.intel.com>
+Description:
+		Shows type of the plug on the cable:
+		- type-a - Standard A
+		- type-b - Standard B
+		- type-c
+		- captive
+
+What:		/sys/class/typec/<port>-cable/identity/
+Date:		April 2017
+Contact:	Heikki Krogerus <heikki.krogerus@linux.intel.com>
+Description:
+		This directory appears only if the port device driver is capable
+		of showing the result of Discover Identity USB power delivery
+		command. That will not always be possible even when USB power
+		delivery is supported. If the directory exists, it will have an
+		attribute for every VDO returned by Discover Identity command.
+
+What:		/sys/class/typec/<port>-cable/identity/id_header
+Date:		April 2017
+Contact:	Heikki Krogerus <heikki.krogerus@linux.intel.com>
+Description:
+		ID Header VDO part of Discover Identity command result. The
+		value will show 0 until Discover Identity command result becomes
+		available. The value can be polled.
+
+What:		/sys/class/typec/<port>-cable/identity/cert_stat
+Date:		April 2017
+Contact:	Heikki Krogerus <heikki.krogerus@linux.intel.com>
+Description:
+		Cert Stat VDO part of Discover Identity command result. The
+		value will show 0 until Discover Identity command result becomes
+		available. The value can be polled.
+
+What:		/sys/class/typec/<port>-cable/identity/product
+Date:		April 2017
+Contact:	Heikki Krogerus <heikki.krogerus@linux.intel.com>
+Description:
+		Product VDO part of Discover Identity command result. The value
+		will show 0 until Discover Identity command result becomes
+		available. The value can be polled.
+
+
+Alternate Mode devices.
+
+The alternate modes will have Standard or Vendor ID (SVID) assigned by USB-IF.
+The ports, partners and cable plugs can have alternate modes. A supported SVID
+will consist of a set of modes. Every SVID a port/partner/plug supports will
+have a device created for it, and every supported mode for a supported SVID will
+have its own directory under that device. Below <dev> refers to the device for
+the alternate mode.
+
+What:		/sys/class/typec/<port|partner|cable>/<dev>/svid
+Date:		April 2017
+Contact:	Heikki Krogerus <heikki.krogerus@linux.intel.com>
+Description:
+		The SVID (Standard or Vendor ID) assigned by USB-IF for this
+		alternate mode.
+
+What:		/sys/class/typec/<port|partner|cable>/<dev>/mode<index>/
+Date:		April 2017
+Contact:	Heikki Krogerus <heikki.krogerus@linux.intel.com>
+Description:
+		Every supported mode will have its own directory. The name of
+		a mode will be "mode<index>" (for example mode1), where <index>
+		is the actual index to the mode VDO returned by Discover Modes
+		USB power delivery command.
+
+What:		/sys/class/typec/<port|partner|cable>/<dev>/mode<index>/description
+Date:		April 2017
+Contact:	Heikki Krogerus <heikki.krogerus@linux.intel.com>
+Description:
+		Shows description of the mode. The description is optional for
+		the drivers, just like with the Billboard Devices.
+
+What:		/sys/class/typec/<port|partner|cable>/<dev>/mode<index>/vdo
+Date:		April 2017
+Contact:	Heikki Krogerus <heikki.krogerus@linux.intel.com>
+Description:
+		Shows the VDO in hexadecimal returned by Discover Modes command
+		for this mode.
+
+What:		/sys/class/typec/<port|partner|cable>/<dev>/mode<index>/active
+Date:		April 2017
+Contact:	Heikki Krogerus <heikki.krogerus@linux.intel.com>
+Description:
+		Shows if the mode is active or not. The attribute can be used
+		for entering/exiting the mode with partners and cable plugs, and
+		with the port alternate modes it can be used for disabling
+		support for specific alternate modes. Entering/exiting modes is
+		supported as synchronous operation so write(2) to the attribute
+		does not return until the enter/exit mode operation has
+		finished. The attribute is notified when the mode is
+		entered/exited so poll(2) on the attribute wakes up.
+		Entering/exiting a mode will also generate uevent KOBJ_CHANGE.
+
+		Valid values: yes, no
+
+What:		/sys/class/typec/<port>/<dev>/mode<index>/supported_roles
+Date:		April 2017
+Contact:	Heikki Krogerus <heikki.krogerus@linux.intel.com>
+Description:
+		Space separated list of the supported roles.
+
+		This attribute is available for the devices describing the
+		alternate modes a port supports, and it will not be exposed with
+		the devices presenting the alternate modes the partners or cable
+		plugs support.
+
+		Valid values: source, sink
diff --git a/Documentation/usb/typec.rst b/Documentation/usb/typec.rst
new file mode 100644
index 000000000000..b67a46779de9
--- /dev/null
+++ b/Documentation/usb/typec.rst
@@ -0,0 +1,184 @@
+
+USB Type-C connector class
+==========================
+
+Introduction
+------------
+
+The typec class is meant for describing the USB Type-C ports in a system to the
+user space in unified fashion. The class is designed to provide nothing else
+except the user space interface implementation in hope that it can be utilized
+on as many platforms as possible.
+
+The platforms are expected to register every USB Type-C port they have with the
+class. In a normal case the registration will be done by a USB Type-C or PD PHY
+driver, but it may be a driver for firmware interface such as UCSI, driver for
+USB PD controller or even driver for Thunderbolt3 controller. This document
+considers the component registering the USB Type-C ports with the class as "port
+driver".
+
+On top of showing the capabilities, the class also offer user space control over
+the roles and alternate modes of ports, partners and cable plugs when the port
+driver is capable of supporting those features.
+
+The class provides an API for the port drivers described in this document. The
+attributes are described in Documentation/ABI/testing/sysfs-class-typec.
+
+User space interface
+--------------------
+Every port will be presented as its own device under /sys/class/typec/. The
+first port will be named "port0", the second "port1" and so on.
+
+When connected, the partner will be presented also as its own device under
+/sys/class/typec/. The parent of the partner device will always be the port it
+is attached to. The partner attached to port "port0" will be named
+"port0-partner". Full path to the device would be
+/sys/class/typec/port0/port0-partner/.
+
+The cable and the two plugs on it may also be optionally presented as their own
+devices under /sys/class/typec/. The cable attached to the port "port0" port
+will be named port0-cable and the plug on the SOP Prime end (see USB Power
+Delivery Specification ch. 2.4) will be named "port0-plug0" and on the SOP
+Double Prime end "port0-plug1". The parent of a cable will always be the port,
+and the parent of the cable plugs will always be the cable.
+
+If the port, partner or cable plug supports Alternate Modes, every supported
+Alternate Mode SVID will have their own device describing them. Note that the
+Alternate Mode devices will not be attached to the typec class. The parent of an
+alternate mode will be the device that supports it, so for example an alternate
+mode of port0-partner will be presented under /sys/class/typec/port0-partner/.
+Every mode that is supported will have its own group under the Alternate Mode
+device named "mode<index>", for example /sys/class/typec/port0/<alternate
+mode>/mode1/. The requests for entering/exiting a mode can be done with "active"
+attribute file in that group.
+
+Driver API
+----------
+
+Registering the ports
+~~~~~~~~~~~~~~~~~~~~~
+
+The port drivers will describe every Type-C port they control with struct
+typec_capability data structure, and register them with the following API:
+
+.. kernel-doc:: drivers/usb/typec/typec.c
+   :functions: typec_register_port typec_unregister_port
+
+When registering the ports, the prefer_role member in struct typec_capability
+deserves special notice. If the port that is being registered does not have
+initial role preference, which means the port does not execute Try.SNK or
+Try.SRC by default, the member must have value TYPEC_NO_PREFERRED_ROLE.
+Otherwise if the port executes Try.SNK by default, the member must have value
+TYPEC_DEVICE, and with Try.SRC the value must be TYPEC_HOST.
+
+Registering Partners
+~~~~~~~~~~~~~~~~~~~~
+
+After successful connection of a partner, the port driver needs to register the
+partner with the class. Details about the partner need to be described in struct
+typec_partner_desc. The class copies the details of the partner during
+registration. The class offers the following API for registering/unregistering
+partners.
+
+.. kernel-doc:: drivers/usb/typec/typec.c
+   :functions: typec_register_partner typec_unregister_partner
+
+The class will provide a handle to struct typec_partner if the registration was
+successful, or NULL.
+
+If the partner is USB Power Delivery capable, and the port driver is able to
+show the result of Discover Identity command, the partner descriptor structure
+should include handle to struct usb_pd_identity instance. The class will then
+create a sysfs directory for the identity under the partner device. The result
+of Discover Identity command can then be reported with the following API:
+
+.. kernel-doc:: drivers/usb/typec/typec.c
+   :functions: typec_partner_set_identity
+
+Registering Cables
+~~~~~~~~~~~~~~~~~~
+
+After successful connection of a cable that supports USB Power Delivery
+Structured VDM "Discover Identity", the port driver needs to register the cable
+and one or two plugs, depending if there is CC Double Prime controller present
+in the cable or not. So a cable capable of SOP Prime communication, but not SOP
+Double Prime communication, should only have one plug registered. For more
+information about SOP communication, please read chapter about it from the
+latest USB Power Delivery specification.
+
+The plugs are represented as their own devices. The cable is registered first,
+followed by registration of the cable plugs. The cable will be the parent device
+for the plugs. Details about the cable need to be described in struct
+typec_cable_desc and about a plug in struct typec_plug_desc. The class copies
+the details during registration. The class offers the following API for
+registering/unregistering cables and their plugs:
+
+.. kernel-doc:: drivers/usb/typec/typec.c
+   :functions: typec_register_cable typec_unregister_cable typec_register_plug
+   typec_unregister_plug
+
+The class will provide a handle to struct typec_cable and struct typec_plug if
+the registration is successful, or NULL if it isn't.
+
+If the cable is USB Power Delivery capable, and the port driver is able to show
+the result of Discover Identity command, the cable descriptor structure should
+include handle to struct usb_pd_identity instance. The class will then create a
+sysfs directory for the identity under the cable device. The result of Discover
+Identity command can then be reported with the following API:
+
+.. kernel-doc:: drivers/usb/typec/typec.c
+   :functions: typec_cable_set_identity
+
+Notifications
+~~~~~~~~~~~~~
+
+When the partner has executed a role change, or when the default roles change
+during connection of a partner or cable, the port driver must use the following
+APIs to report it to the class:
+
+.. kernel-doc:: drivers/usb/typec/typec.c
+   :functions: typec_set_data_role typec_set_pwr_role typec_set_vconn_role
+   typec_set_pwr_opmode
+
+Alternate Modes
+~~~~~~~~~~~~~~~
+
+USB Type-C ports, partners and cable plugs may support Alternate Modes. Each
+Alternate Mode will have identifier called SVID, which is either a Standard ID
+given by USB-IF or vendor ID, and each supported SVID can have 1 - 6 modes. The
+class provides struct typec_mode_desc for describing individual mode of a SVID,
+and struct typec_altmode_desc which is a container for all the supported modes.
+
+Ports that support Alternate Modes need to register each SVID they support with
+the following API:
+
+.. kernel-doc:: drivers/usb/typec/typec.c
+   :functions: typec_port_register_altmode
+
+If a partner or cable plug provides a list of SVIDs as response to USB Power
+Delivery Structured VDM Discover SVIDs message, each SVID needs to be
+registered.
+
+API for the partners:
+
+.. kernel-doc:: drivers/usb/typec/typec.c
+   :functions: typec_partner_register_altmode
+
+API for the Cable Plugs:
+
+.. kernel-doc:: drivers/usb/typec/typec.c
+   :functions: typec_plug_register_altmode
+
+So ports, partners and cable plugs will register the alternate modes with their
+own functions, but the registration will always return a handle to struct
+typec_altmode on success, or NULL. The unregistration will happen with the same
+function:
+
+.. kernel-doc:: drivers/usb/typec/typec.c
+   :functions: typec_unregister_altmode
+
+If a partner or cable plug enters or exits a mode, the port driver needs to
+notify the class with the following API:
+
+.. kernel-doc:: drivers/usb/typec/typec.c
+   :functions: typec_altmode_update_active