There is a possibility that usb_role_switch device is unregistered before
the user put usb_role_switch. In this case, the user may still want to
get/set_role() since the user can't sense the changes of usb_role_switch.
This will add a flag to show if usb_role_switch is already registered and
avoid unwanted behaviors.
Signed-off-by: Xu Yang <xu.yang_2@xxxxxxx>
---
Changes in v2:
- new patch during test patch 1
- add registered flag
---
drivers/usb/roles/class.c | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)
diff --git a/drivers/usb/roles/class.c b/drivers/usb/roles/class.c
index 2bad038fb9ad..70165dd86b5d 100644
--- a/drivers/usb/roles/class.c
+++ b/drivers/usb/roles/class.c
@@ -23,6 +23,7 @@ struct usb_role_switch {
struct mutex lock; /* device lock*/
struct module *module; /* the module this device depends on */
enum usb_role role;
+ bool registered;
/* From descriptor */
struct device *usb2_port;
@@ -49,6 +50,9 @@ int usb_role_switch_set_role(struct usb_role_switch *sw, enum usb_role role)
if (IS_ERR_OR_NULL(sw))
return 0;
+ if (!sw->registered)
+ return -EOPNOTSUPP;
+
mutex_lock(&sw->lock);
ret = sw->set(sw, role);
@@ -74,7 +78,7 @@ enum usb_role usb_role_switch_get_role(struct usb_role_switch *sw)
{
enum usb_role role;
- if (IS_ERR_OR_NULL(sw))
+ if (IS_ERR_OR_NULL(sw) || !sw->registered)
return USB_ROLE_NONE;
mutex_lock(&sw->lock);
@@ -357,6 +361,8 @@ usb_role_switch_register(struct device *parent,
return ERR_PTR(ret);
}
+ sw->registered = true;
+
/* TODO: Symlinks for the host port and the device controller. */
return sw;
@@ -371,8 +377,10 @@ EXPORT_SYMBOL_GPL(usb_role_switch_register);
*/
void usb_role_switch_unregister(struct usb_role_switch *sw)
{
- if (!IS_ERR_OR_NULL(sw))
+ if (!IS_ERR_OR_NULL(sw)) {
+ sw->registered = false;
device_unregister(&sw->dev);
+ }
}
EXPORT_SYMBOL_GPL(usb_role_switch_unregister);
--
2.34.1
