usb: musb: only restore devctl when session was set in backup

commit 84ac5d1140f716a616522f952734e850448d2556 upstream.

If the session bit was not set in the backup of devctl register,
restoring devctl would clear the session bit. Therefor, only restore
devctl register when the session bit was set in the backup.

This solves the device enumeration failure in otg mode exposed by commit
56f487c (PM / Runtime: Update last_busy in rpm_resume).

Signed-off-by: Bin Liu <b-liu@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/musb/musb_core.c b/drivers/usb/musb/musb_core.c
index 39fd95833eb8317b63f4f1e1a781f611bfcda5cd..c84f4d0816e56be7db5519e11d471740e5e28d8c 100644 (file)
--- a/drivers/usb/musb/musb_core.c
+++ b/drivers/usb/musb/musb_core.c
@@ -2429,7 +2429,8 @@ static void musb_restore_context(struct musb *musb)
        musb_writew(musb_base, MUSB_INTRTXE, musb->intrtxe);
        musb_writew(musb_base, MUSB_INTRRXE, musb->intrrxe);
        musb_writeb(musb_base, MUSB_INTRUSBE, musb->context.intrusbe);
-       musb_writeb(musb_base, MUSB_DEVCTL, musb->context.devctl);
+       if (musb->context.devctl & MUSB_DEVCTL_SESSION)
+               musb_writeb(musb_base, MUSB_DEVCTL, musb->context.devctl);
 
        for (i = 0; i < musb->config->num_eps; ++i) {
                struct musb_hw_ep       *hw_ep;