usb: dwc3: gadget: implement dwc3_gadget_get_link_state

This function will be used during hibernation to get
the current link state. It will be needed at least
for Hibernation support.
Signed-off-by: Paul Zimmerman <paulz@synopsys.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

drivers/usb/dwc3/gadget.c

@@ -67,6 +67,22 @@ int dwc3_gadget_set_test_mode(struct dwc3 *dwc, int mode)
 	return 0;
 }
 
+/**
+ * dwc3_gadget_get_link_state - Gets current state of USB Link
+ * @dwc: pointer to our context structure
+ *
+ * Caller should take care of locking. This function will
+ * return the link state on success (>= 0) or -ETIMEDOUT.
+ */
+int dwc3_gadget_get_link_state(struct dwc3 *dwc)
+{
+	u32		reg;
+
+	reg = dwc3_readl(dwc->regs, DWC3_DSTS);
+
+	return DWC3_DSTS_USBLNKST(reg);
+}
+
 /**
  * dwc3_gadget_set_link_state - Sets USB Link to a particular State
  * @dwc: pointer to our context structure

drivers/usb/dwc3/gadget.h

@@ -86,6 +86,7 @@ void dwc3_gadget_giveback(struct dwc3_ep *dep, struct dwc3_request *req,
 		int status);
 
 int dwc3_gadget_set_test_mode(struct dwc3 *dwc, int mode);
+int dwc3_gadget_get_link_state(struct dwc3 *dwc);
 int dwc3_gadget_set_link_state(struct dwc3 *dwc, enum dwc3_link_state state);
 
 void dwc3_ep0_interrupt(struct dwc3 *dwc,