greybus: connection: remove 'struct device' from 'struct gb_connection'

We don't want this in the driver core, as nothing will be binding to it,
that's the job of a bundle.  So remove the struct device and use a kref
to handle reference counting instead.

Note, I don't think we really need a kref, but it keeps the lifetime the
same as before, and is the simplest change for now.  In the future it
might be easier to just attach all connections to the bundle and clean
them up when the bundle is removed.

Also remove the cport sysfs documentation as it's no longer relevant.
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Reviewed-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Alex Elder <elder@linaro.org>
Reviewed-by: Johan Hovold <johan@hovoldconsulting.com>

drivers/staging/greybus/Documentation/sysfs-bus-greybus

@@ -155,40 +155,3 @@ Description:
 		process watching the file will be woken up, and the new
 		value can be read. It's a "poor-man's IPC", yes, but
 		simplifies the Android userspace code immensely.
-
-What:		/sys/bus/greybus/device/endoE:M:I:B:C
-Date:		October 2015
-KernelVersion:	4.XX
-Contact:	Greg Kroah-Hartman <greg@kroah.com>
-Description:
-		A cport C within bundle B, C is replaced by a 2-byte
-		number representing the cport.
-
-What:		/sys/bus/greybus/device/endoE:M:I:B:C/ap_cport_id
-Date:		October 2015
-KernelVersion:	4.XX
-Contact:	Greg Kroah-Hartman <greg@kroah.com>
-Description:
-		The cport ID of the AP, to which cport of the module is
-		connected.
-
-What:		/sys/bus/greybus/device/endoE:M:I:B:C/protocol_id
-Date:		October 2015
-KernelVersion:	4.XX
-Contact:	Greg Kroah-Hartman <greg@kroah.com>
-Description:
-		The protocol ID of a Greybus cport.
-
-What:		/sys/bus/greybus/device/endoE:M:I:B:C/state
-Date:		October 2015
-KernelVersion:	4.XX
-Contact:	Greg Kroah-Hartman <greg@kroah.com>
-Description:
-		The current state of a Greybus connection.
-
-		It will be one of the following values:
-		0 - invalid
-		1 - disabled
-		2 - enabled
-		3 - error
-		4 - destroying

drivers/staging/greybus/connection.c

@@ -67,63 +67,18 @@ void greybus_data_rcvd(struct greybus_host_device *hd, u16 cport_id,
 }
 EXPORT_SYMBOL_GPL(greybus_data_rcvd);
 
-static ssize_t state_show(struct device *dev, struct device_attribute *attr,
-			  char *buf)
-{
-	struct gb_connection *connection = to_gb_connection(dev);
-	enum gb_connection_state state;
-
-	spin_lock_irq(&connection->lock);
-	state = connection->state;
-	spin_unlock_irq(&connection->lock);
-
-	return sprintf(buf, "%d\n", state);
-}
-static DEVICE_ATTR_RO(state);
-
-static ssize_t
-protocol_id_show(struct device *dev, struct device_attribute *attr, char *buf)
-{
-	struct gb_connection *connection = to_gb_connection(dev);
-
-	if (connection->protocol)
-		return sprintf(buf, "%d\n", connection->protocol->id);
-	else
-		return -EINVAL;
-}
-static DEVICE_ATTR_RO(protocol_id);
-
-static ssize_t
-ap_cport_id_show(struct device *dev, struct device_attribute *attr, char *buf)
-{
-	struct gb_connection *connection = to_gb_connection(dev);
-	return sprintf(buf, "%hu\n", connection->hd_cport_id);
-}
-static DEVICE_ATTR_RO(ap_cport_id);
-
-static struct attribute *connection_attrs[] = {
-	&dev_attr_state.attr,
-	&dev_attr_protocol_id.attr,
-	&dev_attr_ap_cport_id.attr,
-	NULL,
-};
-
-ATTRIBUTE_GROUPS(connection);
+static DEFINE_MUTEX(connection_mutex);
 
-static void gb_connection_release(struct device *dev)
+static void gb_connection_kref_release(struct kref *kref)
 {
-	struct gb_connection *connection = to_gb_connection(dev);
+	struct gb_connection *connection;
 
+	connection = container_of(kref, struct gb_connection, kref);
 	destroy_workqueue(connection->wq);
 	kfree(connection);
+	mutex_unlock(&connection_mutex);
 }
 
-struct device_type greybus_connection_type = {
-	.name =		"greybus_connection",
-	.release =	gb_connection_release,
-};
-
-
 int svc_update_connection(struct gb_interface *intf,
 			  struct gb_connection *connection)
 {
@@ -133,13 +88,7 @@ int svc_update_connection(struct gb_interface *intf,
 	if (!bundle)
 		return -EINVAL;
 
-	device_del(&connection->dev);
 	connection->bundle = bundle;
-	connection->dev.parent = &bundle->dev;
-	dev_set_name(&connection->dev, "%s:%d", dev_name(&bundle->dev),
-		     GB_SVC_CPORT_ID);
-
-	WARN_ON(device_add(&connection->dev));
 
 	spin_lock_irq(&gb_connections_lock);
 	list_add(&connection->bundle_links, &bundle->connections);
@@ -210,24 +159,7 @@ gb_connection_create_range(struct greybus_host_device *hd,
 	if (!connection->wq)
 		goto err_free_connection;
 
-	connection->dev.parent = parent;
-	connection->dev.bus = &greybus_bus_type;
-	connection->dev.type = &greybus_connection_type;
-	connection->dev.groups = connection_groups;
-	device_initialize(&connection->dev);
-	dev_set_name(&connection->dev, "%s:%d",
-		     dev_name(parent), cport_id);
-
-	retval = device_add(&connection->dev);
-	if (retval) {
-		connection->hd_cport_id = CPORT_ID_BAD;
-		put_device(&connection->dev);
-
-		dev_err(parent, "failed to register connection to cport %04hx: %d\n",
-				cport_id, retval);
-
-		goto err_remove_ida;
-	}
+	kref_init(&connection->kref);
 
 	spin_lock_irq(&gb_connections_lock);
 	list_add(&connection->hd_links, &hd->connections);
@@ -524,7 +456,8 @@ void gb_connection_destroy(struct gb_connection *connection)
 	ida_simple_remove(id_map, connection->hd_cport_id);
 	connection->hd_cport_id = CPORT_ID_BAD;
 
-	device_unregister(&connection->dev);
+	kref_put_mutex(&connection->kref, gb_connection_kref_release,
+		       &connection_mutex);
 }
 
 void gb_connection_latency_tag_enable(struct gb_connection *connection)

drivers/staging/greybus/connection.h

@@ -24,7 +24,7 @@ enum gb_connection_state {
 struct gb_connection {
 	struct greybus_host_device	*hd;
 	struct gb_bundle		*bundle;
-	struct device			dev;
+	struct kref			kref;
 	u16				hd_cport_id;
 	u16				intf_cport_id;
 
@@ -48,7 +48,6 @@ struct gb_connection {
 
 	void				*private;
 };
-#define to_gb_connection(d) container_of(d, struct gb_connection, dev)
 
 int svc_update_connection(struct gb_interface *intf,
 			  struct gb_connection *connection);