greybus: Add workqueue to handle vibrator timeout

In the beginning, module side can control the vibrator timeout value,
it can disable vibrator until timeout. But after Runtime PM control added
in, AP side didn't know when module can be suspended, the vibrator
task will be interrupted by suspending event.

Because of this problem, the module can not be in charge of counting down
the timeout value, it is now up to the AP to manage this. So add workqueue
to handle the vibrator timeout.
Signed-off-by: NAnn Chen <chen_ann@projectara.com>
Reviewed-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@google.com>

drivers/staging/greybus/vibrator.c

@@ -21,36 +21,27 @@ struct gb_vibrator_device {
 	struct gb_connection	*connection;
 	struct device		*dev;
 	int			minor;		/* vibrator minor number */
+	struct delayed_work     delayed_work;
 };
 
 /* Greybus Vibrator operation types */
 #define	GB_VIBRATOR_TYPE_ON			0x02
 #define	GB_VIBRATOR_TYPE_OFF			0x03
 
-struct gb_vibrator_on_request {
-	__le16	timeout_ms;
-};
-
-static int turn_on(struct gb_vibrator_device *vib, u16 timeout_ms)
+static int turn_off(struct gb_vibrator_device *vib)
 {
-	struct gb_vibrator_on_request request;
 	struct gb_bundle *bundle = vib->connection->bundle;
 	int ret;
 
-	ret = gb_pm_runtime_get_sync(bundle);
-	if (ret)
-		return ret;
-
-	request.timeout_ms = cpu_to_le16(timeout_ms);
-	ret = gb_operation_sync(vib->connection, GB_VIBRATOR_TYPE_ON,
-			&request, sizeof(request), NULL, 0);
+	ret = gb_operation_sync(vib->connection, GB_VIBRATOR_TYPE_OFF,
+			NULL, 0, NULL, 0);
 
 	gb_pm_runtime_put_autosuspend(bundle);
 
 	return ret;
 }
 
-static int turn_off(struct gb_vibrator_device *vib)
+static int turn_on(struct gb_vibrator_device *vib, u16 timeout_ms)
 {
 	struct gb_bundle *bundle = vib->connection->bundle;
 	int ret;
@@ -59,12 +50,29 @@ static int turn_off(struct gb_vibrator_device *vib)
 	if (ret)
 		return ret;
 
-	ret = gb_operation_sync(vib->connection, GB_VIBRATOR_TYPE_OFF,
+	/* Vibrator was switched ON earlier */
+	if (cancel_delayed_work_sync(&vib->delayed_work))
+		turn_off(vib);
+
+	ret = gb_operation_sync(vib->connection, GB_VIBRATOR_TYPE_ON,
 			NULL, 0, NULL, 0);
+	if (ret) {
+		gb_pm_runtime_put_autosuspend(bundle);
+		return ret;
+	}
 
-	gb_pm_runtime_put_autosuspend(bundle);
+	schedule_delayed_work(&vib->delayed_work, msecs_to_jiffies(timeout_ms));
 
-	return ret;
+	return 0;
+}
+
+static void gb_vibrator_worker(struct work_struct *work)
+{
+	struct delayed_work *delayed_work = to_delayed_work(work);
+	struct gb_vibrator_device *vib =
+		container_of(delayed_work, struct gb_vibrator_device, delayed_work);
+
+	turn_off(vib);
 }
 
 static ssize_t timeout_store(struct device *dev, struct device_attribute *attr,
@@ -174,6 +182,8 @@ static int gb_vibrator_probe(struct gb_bundle *bundle,
 	}
 #endif
 
+	INIT_DELAYED_WORK(&vib->delayed_work, gb_vibrator_worker);
+
 	gb_pm_runtime_put_autosuspend(bundle);
 
 	return 0;
@@ -199,6 +209,9 @@ static void gb_vibrator_disconnect(struct gb_bundle *bundle)
 	if (ret)
 		gb_pm_runtime_get_noresume(bundle);
 
+	if (cancel_delayed_work_sync(&vib->delayed_work))
+		turn_off(vib);
+
 #if LINUX_VERSION_CODE <= KERNEL_VERSION(3,11,0)
 	sysfs_remove_group(&vib->dev->kobj, vibrator_groups[0]);
 #endif