[PATCH 4.9 11/60] usb: musb: dsps: keep VBUS on for host-only mode

From: Greg Kroah-Hartman
Date: Mon Jun 19 2017 - 11:28:29 EST

4.9-stable review patch. If anyone has any objections, please let me know.


From: Bin Liu <b-liu@xxxxxx>

commit b3addcf0d1f04f53fcc302577d5a5e964c18531a upstream.

Currently VBUS is turned off while a usb device is detached, and turned
on again by the polling routine. This short period VBUS loss prevents
usb modem to switch mode.

VBUS should be constantly on for host-only mode, so this changes the
driver to not turn off VBUS for host-only mode.

Fixes: 2f3fd2c5bde1 ("usb: musb: Prepare dsps glue layer for PM runtime support")
Reported-by: Moreno Bartalucci <moreno.bartalucci@xxxxxxxxxxxx>
Acked-by: Tony Lindgren <tony@xxxxxxxxxxx>
Signed-off-by: Bin Liu <b-liu@xxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

drivers/usb/musb/musb_dsps.c | 6 ++++++
1 file changed, 6 insertions(+)

--- a/drivers/usb/musb/musb_dsps.c
+++ b/drivers/usb/musb/musb_dsps.c
@@ -213,6 +213,12 @@ static int dsps_check_status(struct musb
+ /* keep VBUS on for host-only mode */
+ if (musb->port_mode == MUSB_PORT_MODE_HOST) {
+ mod_timer(&glue->timer, jiffies +
+ msecs_to_jiffies(wrp->poll_timeout));
+ break;
+ }
musb_writeb(musb->mregs, MUSB_DEVCTL, 0);
skip_session = 1;
/* fall */