usb: typec: API for controlling USB Type-C Multiplexers

[linux.git] / Documentation / driver-api / usb / typec.rst

diff --git a/Documentation/driver-api/usb/typec.rst b/Documentation/driver-api/usb/typec.rst
index 8a7249f2ff04ca8c24e5ae9174fb1ba2a93d0461..feb31946490b01c13106e2f9f43d1d28fd918ea0 100644 (file)
--- a/Documentation/driver-api/usb/typec.rst
+++ b/Documentation/driver-api/usb/typec.rst
@@ -61,7 +61,7 @@ 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
+.. kernel-doc:: drivers/usb/typec/class.c
    :functions: typec_register_port typec_unregister_port
 
 When registering the ports, the prefer_role member in struct typec_capability
@@ -80,7 +80,7 @@ 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
+.. kernel-doc:: drivers/usb/typec/class.c
    :functions: typec_register_partner typec_unregister_partner
 
 The class will provide a handle to struct typec_partner if the registration was
@@ -92,7 +92,7 @@ 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
+.. kernel-doc:: drivers/usb/typec/class.c
    :functions: typec_partner_set_identity
 
 Registering Cables
@@ -113,7 +113,7 @@ 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
+.. kernel-doc:: drivers/usb/typec/class.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
@@ -125,7 +125,7 @@ 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
+.. kernel-doc:: drivers/usb/typec/class.c
    :functions: typec_cable_set_identity
 
 Notifications
@@ -135,7 +135,7 @@ 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
+.. kernel-doc:: drivers/usb/typec/class.c
    :functions: typec_set_data_role typec_set_pwr_role typec_set_vconn_role typec_set_pwr_opmode
 
 Alternate Modes
@@ -150,7 +150,7 @@ 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
+.. kernel-doc:: drivers/usb/typec/class.c
    :functions: typec_port_register_altmode
 
 If a partner or cable plug provides a list of SVIDs as response to USB Power
@@ -159,12 +159,12 @@ registered.
 
 API for the partners:
 
-.. kernel-doc:: drivers/usb/typec/typec.c
+.. kernel-doc:: drivers/usb/typec/class.c
    :functions: typec_partner_register_altmode
 
 API for the Cable Plugs:
 
-.. kernel-doc:: drivers/usb/typec/typec.c
+.. kernel-doc:: drivers/usb/typec/class.c
    :functions: typec_plug_register_altmode
 
 So ports, partners and cable plugs will register the alternate modes with their
@@ -172,11 +172,62 @@ 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
+.. kernel-doc:: drivers/usb/typec/class.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
+.. kernel-doc:: drivers/usb/typec/class.c
    :functions: typec_altmode_update_active
+
+Multiplexer/DeMultiplexer Switches
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+USB Type-C connectors may have one or more mux/demux switches behind them. Since
+the plugs can be inserted right-side-up or upside-down, a switch is needed to
+route the correct data pairs from the connector to the USB controllers. If
+Alternate or Accessory Modes are supported, another switch is needed that can
+route the pins on the connector to some other component besides USB. USB Type-C
+Connector Class supplies an API for registering those switches.
+
+.. kernel-doc:: drivers/usb/typec/mux.c
+   :functions: typec_switch_register typec_switch_unregister typec_mux_register typec_mux_unregister
+
+In most cases the same physical mux will handle both the orientation and mode.
+However, as the port drivers will be responsible for the orientation, and the
+alternate mode drivers for the mode, the two are always separated into their
+own logical components: "mux" for the mode and "switch" for the orientation.
+
+When a port is registered, USB Type-C Connector Class requests both the mux and
+the switch for the port. The drivers can then use the following API for
+controlling them:
+
+.. kernel-doc:: drivers/usb/typec/class.c
+   :functions: typec_set_orientation typec_set_mode
+
+If the connector is dual-role capable, there may also be a switch for the data
+role. USB Type-C Connector Class does not supply separate API for them. The
+port drivers can use USB Role Class API with those.
+
+Illustration of the muxes behind a connector that supports an alternate mode:
+
+                     ------------------------
+                     |       Connector      |
+                     ------------------------
+                            |         |
+                     ------------------------
+                      \     Orientation    /
+                       --------------------
+                                |
+                       --------------------
+                      /        Mode        \
+                     ------------------------
+                         /              \
+      ------------------------        --------------------
+      |       Alt Mode       |       /      USB Role      \
+      ------------------------      ------------------------
+                                         /            \
+                     ------------------------      ------------------------
+                     |       USB Host       |      |       USB Device     |
+                     ------------------------      ------------------------