usb: gadget: udc-core: move sysfs_notify() to a workqueue

usb_gadget_set_state() will call sysfs_notify()
which might sleep. Some users might want to call
usb_gadget_set_state() from the very IRQ handler
which actually changes the gadget state.

Instead of having every UDC driver add their own
workqueue for such a simple notification, we're
adding it generically to our struct usb_gadget,
so the details are hidden from all UDC drivers.

Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Felipe Balbi <balbi@ti.com>

1 files changed, 4 insertions, 0 deletions

diff --git a/include/linux/usb/gadget.h b/include/linux/usb/gadget.h
index f1b0dca60f12..942ef5e053bf 100644
--- a/include/linux/usb/gadget.h
+++ b/include/linux/usb/gadget.h
@@ -22,6 +22,7 @@
 #include <linux/slab.h>
 #include <linux/scatterlist.h>
 #include <linux/types.h>
+#include <linux/workqueue.h>
 #include <linux/usb/ch9.h>
 
 struct usb_ep;
@@ -475,6 +476,7 @@ struct usb_gadget_ops {
 
 /**
  * struct usb_gadget - represents a usb slave device
+ * @work: (internal use) Workqueue to be used for sysfs_notify()
  * @ops: Function pointers used to access hardware-specific operations.
  * @ep0: Endpoint zero, used when reading or writing responses to
  *      driver setup() requests
@@ -520,6 +522,7 @@ struct usb_gadget_ops {
  * device is acting as a B-Peripheral (so is_a_peripheral is false).
  */
 struct usb_gadget {
+        struct work_struct              work;
         /* readonly to gadget driver */
         const struct usb_gadget_ops     *ops;
         struct usb_ep                   *ep0;
@@ -538,6 +541,7 @@ struct usb_gadget {
         unsigned                        out_epnum;
         unsigned                        in_epnum;
 };
+#define work_to_gadget(w)       (container_of((w), struct usb_gadget, work))
 
 static inline void set_gadget_data(struct usb_gadget *gadget, void *data)
         { dev_set_drvdata(&gadget->dev, data); }