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

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).

Cc: <stable@vger.kernel.org> # v4.2+
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 0286a39ea01d038854de298e9385f4ced3449bc2..f824336def5c558de1362f9dead14880ba2fb88f 100644 (file)
--- a/drivers/usb/musb/musb_core.c
+++ b/drivers/usb/musb/musb_core.c
@@ -2418,7 +2418,8 @@ 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;