usb: atmel_usba_udc: Mask status with enabled irqs

Avoid interpreting useless status flags when we're not waiting for such
events by masking the status variable with the interrupt enabled register
value.

Acked-by: Alexandre Belloni <[e-mail]>
Reported-by: Patrice VILCHEZ <[e-mail]>
Signed-off-by: Boris Brezillon <[e-mail]>
Signed-off-by: Felipe Balbi <[e-mail]>

drivers/usb/gadget/udc/atmel_usba_udc.c

···
 
 	spin_lock(&udc->lock);
 
-	status = usba_readl(udc, INT_STA);
+	status = usba_readl(udc, INT_STA) & usba_readl(udc, INT_ENB);
 	DBG(DBG_INT, "irq, status=%#08x\n", status);
 
 	if (status & USBA_DET_SUSPEND) {
 		toggle_bias(udc, 0);
 		usba_writel(udc, INT_CLR, USBA_DET_SUSPEND);
+		usba_writel(udc, INT_ENB,
+			    usba_readl(udc, INT_ENB) | USBA_WAKE_UP);
 		udc->bias_pulse_needed = true;
 		DBG(DBG_BUS, "Suspend detected\n");
 		if (udc->gadget.speed != USB_SPEED_UNKNOWN
···
 	if (status & USBA_WAKE_UP) {
 		toggle_bias(udc, 1);
 		usba_writel(udc, INT_CLR, USBA_WAKE_UP);
+		usba_writel(udc, INT_ENB,
+			    usba_readl(udc, INT_ENB) & ~USBA_WAKE_UP);
 		DBG(DBG_BUS, "Wake Up CPU detected\n");
 	}