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From:   Prashant Malani <pmalani@chromium.org>
To:     linux-usb@vger.kernel.org, gregkh@linuxfoundation.org,
        heikki.krogerus@linux.intel.com
Cc:     bleung@chromium.org, Prashant Malani <pmalani@chromium.org>,
        Jonathan Corbet <corbet@lwn.net>,
        linux-doc@vger.kernel.org (open list:DOCUMENTATION),
        linux-kernel@vger.kernel.org (open list)
Subject: [PATCH] usb: typec: Add bus type for plug alt modes
Date:   Wed,  2 Dec 2020 19:08:47 -0800
Message-Id: <20201203030846.51669-1-pmalani@chromium.org>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

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@chromium.org>
Cc: Heikki Krogerus <heikki.krogerus@linux.intel.com>
---
 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