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usb: roles: Link the switch to its connector 

This is probable useful information to have in user space in
general, but it's primarily needed for the xHCI DbC (Debug
Capability). When xHCI DbC is being used, the USB port needs
to be muxed to the xHCI even in device role. In xHCI DbC mode,
the xHCI is the USB device controller.

Tested-by: Uday Bhat <uday.m.bhat@intel.com>
Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Reviewed-by: Prashant Malani <pmalani@chromium.org>
Link: https://lore.kernel.org/r/20240213130018.3029991-2-heikki.krogerus@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Heikki Krogerus 2024-02-13 15:00:17 +02:00 committed by Greg Kroah-Hartman
parent 503d6ed00f
commit 9a270ec7bf
2 changed files with 44 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
Documentation/ABI/testing/sysfs-class-usb_role
View File

@ -19,3 +19,9 @@ Description:
- none
- host
- device
What: /sys/class/usb_role/<switch>/connector
Date: Feb 2024
Contact: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Description:
Optional symlink to the USB Type-C connector.

40
drivers/usb/roles/class.c
View File

@ -7,6 +7,7 @@
* Hans de Goede <hdegoede@redhat.com>
*/
#include <linux/component.h>
#include <linux/usb/role.h>
#include <linux/property.h>
#include <linux/device.h>
@ -34,6 +35,32 @@ struct usb_role_switch {
#define to_role_switch(d) container_of(d, struct usb_role_switch, dev)
static int connector_bind(struct device *dev, struct device *connector, void *data)
{
int ret;
ret = sysfs_create_link(&dev->kobj, &connector->kobj, "connector");
if (ret)
return ret;
ret = sysfs_create_link(&connector->kobj, &dev->kobj, "usb-role-switch");
if (ret)
sysfs_remove_link(&dev->kobj, "connector");
return ret;
}
static void connector_unbind(struct device *dev, struct device *connector, void *data)
{
sysfs_remove_link(&connector->kobj, "usb-role-switch");
sysfs_remove_link(&dev->kobj, "connector");
}
static const struct component_ops connector_ops = {
.bind = connector_bind,
.unbind = connector_unbind,
};
/**
* usb_role_switch_set_role - Set USB role for a switch
* @sw: USB role switch
@ -352,6 +379,12 @@ usb_role_switch_register(struct device *parent,
return ERR_PTR(ret);
}
if (dev_fwnode(&sw->dev)) {
ret = component_add(&sw->dev, &connector_ops);
if (ret)
dev_warn(&sw->dev, "failed to add component\n");
}
/* TODO: Symlinks for the host port and the device controller. */
return sw;
@ -366,8 +399,11 @@ EXPORT_SYMBOL_GPL(usb_role_switch_register);
*/
void usb_role_switch_unregister(struct usb_role_switch *sw)
{
if (!IS_ERR_OR_NULL(sw))
device_unregister(&sw->dev);
if (IS_ERR_OR_NULL(sw))
return;
if (dev_fwnode(&sw->dev))
component_del(&sw->dev, &connector_ops);
device_unregister(&sw->dev);
}
EXPORT_SYMBOL_GPL(usb_role_switch_unregister);