[PATCH] usb: musb: fix idling for suspend after disconnect interrupt

[Tony Lindgren <tony@atomide.com>]

When disconnected as USB B-device, we sometimes get a suspend interrupt
after disconnect interrupt. In that case we have devctl set to 99 with
VBUS still valid and musb_pm_runtime_check_session() wrongly things we
have an active session. We have no other interrupts after disconnect
coming in this case at least with the omap2430 glue.

Let's fix the issue by checking the interrupt status again with
delayed work for the devctl 99 case. In the suspend after disconnect
case the devctl session bit has cleared by then and musb can idle.
For a typical USB B-device connect case we just continue with normal
interrupts.

Cc: Merlijn Wajer <merlijn@wizzup.org>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Sebastian Reichel <sre@kernel.org>
Signed-off-by: Tony Lindgren <tony@atomide.com>
---
 drivers/usb/musb/musb_core.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/usb/musb/musb_core.c b/drivers/usb/musb/musb_core.c
--- a/drivers/usb/musb/musb_core.c
+++ b/drivers/usb/musb/musb_core.c
@@ -1943,6 +1943,9 @@ ATTRIBUTE_GROUPS(musb);
 #define MUSB_QUIRK_B_INVALID_VBUS_91	(MUSB_DEVCTL_BDEVICE | \
 					 (2 << MUSB_DEVCTL_VBUS_SHIFT) | \
 					 MUSB_DEVCTL_SESSION)
+#define MUSB_QUIRK_B_DISCONNECT_99	(MUSB_DEVCTL_BDEVICE | \
+					 (3 << MUSB_DEVCTL_VBUS_SHIFT) | \
+					 MUSB_DEVCTL_SESSION)
 #define MUSB_QUIRK_A_DISCONNECT_19	((3 << MUSB_DEVCTL_VBUS_SHIFT) | \
 					 MUSB_DEVCTL_SESSION)
 
@@ -1965,6 +1968,11 @@ static void musb_pm_runtime_check_session(struct musb *musb)
 	s = MUSB_DEVCTL_FSDEV | MUSB_DEVCTL_LSDEV |
 		MUSB_DEVCTL_HR;
 	switch (devctl & ~s) {
+	case MUSB_QUIRK_B_DISCONNECT_99:
+		musb_dbg(musb, "Poll devctl in case of suspend after disconnect\n");
+		schedule_delayed_work(&musb->irq_work,
+				      msecs_to_jiffies(1000));
+		break;
 	case MUSB_QUIRK_B_INVALID_VBUS_91:
 		if (musb->quirk_retries && !musb->flush_irq_work) {
 			musb_dbg(musb,
-- 
2.24.0