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>

Documentation/usb/typec.rst

+
+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

MAINTAINERS

@@ -13100,6 +13100,15 @@ F:	drivers/usb/
 F:	include/linux/usb.h
 F:	include/linux/usb/
 
+USB TYPEC SUBSYSTEM
+M:	Heikki Krogerus <heikki.krogerus@linux.intel.com>
+L:	linux-usb@vger.kernel.org
+S:	Maintained
+F:	Documentation/ABI/testing/sysfs-class-typec
+F:	Documentation/usb/typec.rst
+F:	drivers/usb/typec/
+F:	include/linux/usb/typec.h
+
 USB UHCI DRIVER
 M:	Alan Stern <stern@rowland.harvard.edu>
 L:	linux-usb@vger.kernel.org

drivers/usb/Kconfig

@@ -162,6 +162,8 @@ source "drivers/usb/phy/Kconfig"
 
 source "drivers/usb/gadget/Kconfig"
 
+source "drivers/usb/typec/Kconfig"
+
 config USB_LED_TRIG
 	bool "USB LED Triggers"
 	depends on LEDS_CLASS && LEDS_TRIGGERS

drivers/usb/Makefile

@@ -62,3 +62,5 @@ obj-$(CONFIG_USB_GADGET)	+= gadget/
 obj-$(CONFIG_USB_COMMON)	+= common/
 
 obj-$(CONFIG_USBIP_CORE)	+= usbip/
+
+obj-$(CONFIG_TYPEC)		+= typec/

drivers/usb/typec/Kconfig

+
+menu "USB Power Delivery and Type-C drivers"
+
+config TYPEC
+	tristate
+
+endmenu

drivers/usb/typec/Makefile

+obj-$(CONFIG_TYPEC)		+= typec.o

include/linux/usb/typec.h

+
+#ifndef __LINUX_USB_TYPEC_H
+#define __LINUX_USB_TYPEC_H
+
+#include <linux/types.h>
+
+/* XXX: Once we have a header for USB Power Delivery, this belongs there */
+#define ALTMODE_MAX_MODES	6
+
+/* USB Type-C Specification releases */
+#define USB_TYPEC_REV_1_0	0x100 /* 1.0 */
+#define USB_TYPEC_REV_1_1	0x110 /* 1.1 */
+#define USB_TYPEC_REV_1_2	0x120 /* 1.2 */
+
+struct typec_altmode;
+struct typec_partner;
+struct typec_cable;
+struct typec_plug;
+struct typec_port;
+
+struct fwnode_handle;
+
+enum typec_port_type {
+	TYPEC_PORT_DFP,
+	TYPEC_PORT_UFP,
+	TYPEC_PORT_DRP,
+};
+
+enum typec_plug_type {
+	USB_PLUG_NONE,
+	USB_PLUG_TYPE_A,
+	USB_PLUG_TYPE_B,
+	USB_PLUG_TYPE_C,
+	USB_PLUG_CAPTIVE,
+};
+
+enum typec_data_role {
+	TYPEC_DEVICE,
+	TYPEC_HOST,
+};
+
+enum typec_role {
+	TYPEC_SINK,
+	TYPEC_SOURCE,
+};
+
+enum typec_pwr_opmode {
+	TYPEC_PWR_MODE_USB,
+	TYPEC_PWR_MODE_1_5A,
+	TYPEC_PWR_MODE_3_0A,
+	TYPEC_PWR_MODE_PD,
+};
+
+enum typec_accessory {
+	TYPEC_ACCESSORY_NONE,
+	TYPEC_ACCESSORY_AUDIO,
+	TYPEC_ACCESSORY_DEBUG,
+};
+
+#define TYPEC_MAX_ACCESSORY	3
+
+/*
+ * struct usb_pd_identity - USB Power Delivery identity data
+ * @id_header: ID Header VDO
+ * @cert_stat: Cert Stat VDO
+ * @product: Product VDO
+ *
+ * USB power delivery Discover Identity command response data.
+ *
+ * REVISIT: This is USB Power Delivery specific information, so this structure
+ * probable belongs to USB Power Delivery header file once we have them.
+ */
+struct usb_pd_identity {
+	u32			id_header;
+	u32			cert_stat;
+	u32			product;
+};
+
+int typec_partner_set_identity(struct typec_partner *partner);
+int typec_cable_set_identity(struct typec_cable *cable);
+
+/*
+ * struct typec_mode_desc - Individual Mode of an Alternate Mode
+ * @index: Index of the Mode within the SVID
+ * @vdo: VDO returned by Discover Modes USB PD command
+ * @desc: Optional human readable description of the mode
+ * @roles: Only for ports. DRP if the mode is available in both roles
+ *
+ * Description of a mode of an Alternate Mode which a connector, cable plug or
+ * partner supports. Every mode will have it's own sysfs group. The details are
+ * the VDO returned by discover modes command, description for the mode and
+ * active flag telling has the mode being entered or not.
+ */
+struct typec_mode_desc {
+	int			index;
+	u32			vdo;
+	char			*desc;
+	/* Only used with ports */
+	enum typec_port_type	roles;
+};
+
+/*
+ * struct typec_altmode_desc - USB Type-C Alternate Mode Descriptor
+ * @svid: Standard or Vendor ID
+ * @n_modes: Number of modes
+ * @modes: Array of modes supported by the Alternate Mode
+ *
+ * Representation of an Alternate Mode that has SVID assigned by USB-IF. The
+ * array of modes will list the modes of a particular SVID that are supported by
+ * a connector, partner of a cable plug.
+ */
+struct typec_altmode_desc {
+	u16			svid;
+	int			n_modes;
+	struct typec_mode_desc	modes[ALTMODE_MAX_MODES];
+};
+
+struct typec_altmode
+*typec_partner_register_altmode(struct typec_partner *partner,
+				struct typec_altmode_desc *desc);
+struct typec_altmode
+*typec_plug_register_altmode(struct typec_plug *plug,
+			     struct typec_altmode_desc *desc);
+struct typec_altmode
+*typec_port_register_altmode(struct typec_port *port,
+			     struct typec_altmode_desc *desc);
+void typec_unregister_altmode(struct typec_altmode *altmode);
+
+struct typec_port *typec_altmode2port(struct typec_altmode *alt);
+
+void typec_altmode_update_active(struct typec_altmode *alt, int mode,
+				 bool active);
+
+enum typec_plug_index {
+	TYPEC_PLUG_SOP_P,
+	TYPEC_PLUG_SOP_PP,
+};
+
+/*
+ * struct typec_plug_desc - USB Type-C Cable Plug Descriptor
+ * @index: SOP Prime for the plug connected to DFP and SOP Double Prime for the
+ *         plug connected to UFP
+ *
+ * Represents USB Type-C Cable Plug.
+ */
+struct typec_plug_desc {
+	enum typec_plug_index	index;
+};
+
+/*
+ * struct typec_cable_desc - USB Type-C Cable Descriptor
+ * @type: The plug type from USB PD Cable VDO
+ * @active: Is the cable active or passive
+ * @identity: Result of Discover Identity command
+ *
+ * Represents USB Type-C Cable attached to USB Type-C port.
+ */
+struct typec_cable_desc {
+	enum typec_plug_type	type;
+	unsigned int		active:1;
+	struct usb_pd_identity	*identity;
+};
+
+/*
+ * struct typec_partner_desc - USB Type-C Partner Descriptor
+ * @usb_pd: USB Power Delivery support
+ * @accessory: Audio, Debug or none.
+ * @identity: Discover Identity command data
+ *
+ * Details about a partner that is attached to USB Type-C port. If @identity
+ * member exists when partner is registered, a directory named "identity" is
+ * created to sysfs for the partner device.
+ */
+struct typec_partner_desc {
+	unsigned int		usb_pd:1;
+	enum typec_accessory	accessory;
+	struct usb_pd_identity	*identity;
+};
+
+/*
+ * struct typec_capability - USB Type-C Port Capabilities
+ * @role: DFP (Host-only), UFP (Device-only) or DRP (Dual Role)
+ * @revision: USB Type-C Specification release. Binary coded decimal
+ * @pd_revision: USB Power Delivery Specification revision if supported
+ * @prefer_role: Initial role preference
+ * @accessory: Supported Accessory Modes
+ * @fwnode: Optional fwnode of the port
+ * @try_role: Set data role preference for DRP port
+ * @dr_set: Set Data Role
+ * @pr_set: Set Power Role
+ * @vconn_set: Set VCONN Role
+ * @activate_mode: Enter/exit given Alternate Mode
+ *
+ * Static capabilities of a single USB Type-C port.
+ */
+struct typec_capability {
+	enum typec_port_type	type;
+	u16			revision; /* 0120H = "1.2" */
+	u16			pd_revision; /* 0300H = "3.0" */
+	int			prefer_role;
+	enum typec_accessory	accessory[TYPEC_MAX_ACCESSORY];
+
+	struct fwnode_handle	*fwnode;
+
+	int		(*try_role)(const struct typec_capability *,
+				    int role);
+
+	int		(*dr_set)(const struct typec_capability *,
+				  enum typec_data_role);
+	int		(*pr_set)(const struct typec_capability *,
+				  enum typec_role);
+	int		(*vconn_set)(const struct typec_capability *,
+				     enum typec_role);
+
+	int		(*activate_mode)(const struct typec_capability *,
+					 int mode, int activate);
+};
+
+/* Specific to try_role(). Indicates the user want's to clear the preference. */
+#define TYPEC_NO_PREFERRED_ROLE	(-1)
+
+struct typec_port *typec_register_port(struct device *parent,
+				       const struct typec_capability *cap);
+void typec_unregister_port(struct typec_port *port);
+
+struct typec_partner *typec_register_partner(struct typec_port *port,
+					     struct typec_partner_desc *desc);
+void typec_unregister_partner(struct typec_partner *partner);
+
+struct typec_cable *typec_register_cable(struct typec_port *port,
+					 struct typec_cable_desc *desc);
+void typec_unregister_cable(struct typec_cable *cable);
+
+struct typec_plug *typec_register_plug(struct typec_cable *cable,
+				       struct typec_plug_desc *desc);
+void typec_unregister_plug(struct typec_plug *plug);
+
+void typec_set_data_role(struct typec_port *port, enum typec_data_role role);
+void typec_set_pwr_role(struct typec_port *port, enum typec_role role);
+void typec_set_vconn_role(struct typec_port *port, enum typec_role role);
+void typec_set_pwr_opmode(struct typec_port *port, enum typec_pwr_opmode mode);
+
+#endif /* __LINUX_USB_TYPEC_H */