[PATCH] usb: typec: Add bus type for plug alt modes

From: Prashant Malani
Date: Wed Dec 02 2020 - 22:10:35 EST


Add the Type C bus for plug alternate modes which are being
registered via the Type C connector class. This ensures that udev events
get generated when plug alternate modes are registered (and not just for
partner/port alternate modes), even though the Type C bus doesn't link
plug alternate mode devices to alternate mode drivers.

Update the Type C bus documentation to mention that there
are alternate mode devices for plugs as well.

Signed-off-by: Prashant Malani <pmalani@xxxxxxxxxxxx>
Cc: Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx>
---
Documentation/driver-api/usb/typec_bus.rst | 6 +++---
drivers/usb/typec/class.c | 8 ++++++--
2 files changed, 9 insertions(+), 5 deletions(-)

diff --git a/Documentation/driver-api/usb/typec_bus.rst b/Documentation/driver-api/usb/typec_bus.rst
index 21c890ae17e5..7874d2f37d9f 100644
--- a/Documentation/driver-api/usb/typec_bus.rst
+++ b/Documentation/driver-api/usb/typec_bus.rst
@@ -15,9 +15,9 @@ modes by using the SVID and the mode number.

:ref:`USB Type-C Connector Class <typec>` provides a device for every alternate
mode a port supports, and separate device for every alternate mode the partner
-supports. The drivers for the alternate modes are bound to the partner alternate
-mode devices, and the port alternate mode devices must be handled by the port
-drivers.
+or cable plug supports. The drivers for the alternate modes are bound to the
+partner alternate mode devices, and the port alternate mode devices must be
+handled by the port drivers.

When a new partner alternate mode device is registered, it is linked to the
alternate mode device of the port that the partner is attached to, that has
diff --git a/drivers/usb/typec/class.c b/drivers/usb/typec/class.c
index 35eec707cb51..74061a699f16 100644
--- a/drivers/usb/typec/class.c
+++ b/drivers/usb/typec/class.c
@@ -478,8 +478,12 @@ typec_register_altmode(struct device *parent,
if (!is_port)
typec_altmode_set_partner(alt);

- /* The partners are bind to drivers */
- if (is_typec_partner(parent))
+ /*
+ * The partners are bind to drivers.
+ * Also set the bus field for plug alt modes so that the udev event occurs on device
+ * registration.
+ */
+ if (is_typec_partner(parent) || is_typec_plug(parent))
alt->adev.dev.bus = &typec_bus;

ret = device_register(&alt->adev.dev);
--
2.29.2.454.gaff20da3a2-goog