[RFC v1 2/2] usb: otg: Temporarily hold wakeupsource on charger

From: Kiran Kumar Raparthy
Date: Thu Aug 28 2014 - 06:07:48 EST

From: Todd Poynor <toddpoynor@xxxxxxxxxx>

usb: otg: Temporarily hold wakeupsource on charger connect and disconnect

Allow other parts of the system to react to the charger connect/disconnect
event without allowing the system to suspend before the other parts can process
the event. This wakeup_source times out after 2 seconds; if nobody else holds a
wakeup_source by that time then the device can sleep.

Cc: Felipe Balbi <balbi@xxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Cc: linux-kernel@xxxxxxxxxxxxxxx
Cc: linux-usb@xxxxxxxxxxxxxxx
Cc: Android Kernel Team <kernel-team@xxxxxxxxxxx>
Cc: John Stultz <john.stultz@xxxxxxxxxx>
Signed-off-by: Todd Poynor <toddpoynor@xxxxxxxxxx>
[kiran: Added context to commit message]
Signed-off-by: Kiran Raparthy <kiran.kumar@xxxxxxxxxx>
drivers/usb/phy/otg-wakeupsource.c | 10 +++++++---
include/linux/usb/otg.h | 2 ++
2 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/drivers/usb/phy/otg-wakeupsource.c b/drivers/usb/phy/otg-wakeupsource.c
index 7c838d1..9f3c5c1 100644
--- a/drivers/usb/phy/otg-wakeupsource.c
+++ b/drivers/usb/phy/otg-wakeupsource.c
@@ -34,8 +34,11 @@ struct otgws_lock {
struct wakeup_source wsource;

-/* VBUS present lock */
+ * VBUS present lock. Also used as a timed lock on charger
+ * connect/disconnect and USB host disconnect, to allow the system
+ * to react to the change in power.
+ */
static struct otgws_lock vbus_lock;

static void otgws_handle_event(unsigned long event)
@@ -59,7 +62,8 @@ static void otgws_handle_event(unsigned long event)
- __pm_relax(&vbus_lock.wsource);
+ __pm_wakeup_event(&vbus_lock.wsource,
+ msecs_to_jiffies(TEMPORARY_HOLD_TIME));

diff --git a/include/linux/usb/otg.h b/include/linux/usb/otg.h
index 154332b..4243747 100644
--- a/include/linux/usb/otg.h
+++ b/include/linux/usb/otg.h
@@ -11,6 +11,8 @@

#include <linux/usb/phy.h>

struct usb_otg {
u8 default_a;


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