usb: musb: da8xx: fix babble condition handling

When babble condition happens, the musb controller might automatically
turns off VBUS. On DA8xx platform, the controller generates drvvbus
interrupt for turning off VBUS along with the babble interrupt.

In this case, we should handle the babble interrupt first and recover
from the babble condition.

This change ignores the drvvbus interrupt if babble interrupt is also
generated at the same time, so the babble recovery routine works
properly.

Cc: [email protected] # v3.16+
Signed-off-by: Bin Liu <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

drivers/usb/musb/da8xx.c

@@ -284,7 +284,15 @@ static irqreturn_t da8xx_musb_interrupt(int irq, void *hci)
 			musb->xceiv->otg->state = OTG_STATE_A_WAIT_VRISE;
 			portstate(musb->port1_status |= USB_PORT_STAT_POWER);
 			del_timer(&musb->dev_timer);
-		} else {
+		} else if (!(musb->int_usb & MUSB_INTR_BABBLE)) {
+			/*
+			 * When babble condition happens, drvvbus interrupt
+			 * is also generated. Ignore this drvvbus interrupt
+			 * and let babble interrupt handler recovers the
+			 * controller; otherwise, the host-mode flag is lost
+			 * due to the MUSB_DEV_MODE() call below and babble
+			 * recovery logic will not be called.
+			 */
 			musb->is_active = 0;
 			MUSB_DEV_MODE(musb);
 			otg->default_a = 0;