[PATCH] usb: udc: Add trace event for usb_gadget_set_state

[Kuen-Han Tsai <khtsai@google.com>]

While the userspace program can be notified of gadget state changes,
timing issue can lead to missed transitions when reading the state
value.

Introduce a trace event for usb_gadget_set_state to reliably track state
transitions.

Signed-off-by: Kuen-Han Tsai <khtsai@google.com>
---
 drivers/usb/gadget/udc/core.c  | 1 +
 drivers/usb/gadget/udc/trace.h | 5 +++++
 2 files changed, 6 insertions(+)

diff --git a/drivers/usb/gadget/udc/core.c b/drivers/usb/gadget/udc/core.c
index d709e24c1fd4..e28fea614496 100644
--- a/drivers/usb/gadget/udc/core.c
+++ b/drivers/usb/gadget/udc/core.c
@@ -1125,6 +1125,7 @@ void usb_gadget_set_state(struct usb_gadget *gadget,
 {
 	gadget->state = state;
 	schedule_work(&gadget->work);
+	trace_usb_gadget_set_state(gadget, 0);
 }
 EXPORT_SYMBOL_GPL(usb_gadget_set_state);
 
diff --git a/drivers/usb/gadget/udc/trace.h b/drivers/usb/gadget/udc/trace.h
index 4e334298b0e8..fa3e6ddf0a12 100644
--- a/drivers/usb/gadget/udc/trace.h
+++ b/drivers/usb/gadget/udc/trace.h
@@ -81,6 +81,11 @@ DECLARE_EVENT_CLASS(udc_log_gadget,
 		__entry->ret)
 );
 
+DEFINE_EVENT(udc_log_gadget, usb_gadget_set_state,
+	TP_PROTO(struct usb_gadget *g, int ret),
+	TP_ARGS(g, ret)
+);
+
 DEFINE_EVENT(udc_log_gadget, usb_gadget_frame_number,
 	TP_PROTO(struct usb_gadget *g, int ret),
 	TP_ARGS(g, ret)
-- 
2.51.0.rc1.163.g2494970778-goog