4 * Copyright (C) 2011 Google, Inc.
6 * This software is licensed under the terms of the GNU General Public
7 * License version 2, as published by the Free Software Foundation, and
8 * may be copied, distributed, and modified under those terms.
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
17 #include <linux/kernel.h>
18 #include <linux/device.h>
19 #include <linux/err.h>
20 #include <linux/module.h>
21 #include <linux/notifier.h>
22 #include <linux/wakelock.h>
23 #include <linux/spinlock.h>
24 #include <linux/usb/otg.h>
26 #define TEMPORARY_HOLD_TIME 2000
28 static bool enabled = true;
29 static struct usb_phy *otgwl_xceiv;
30 static struct notifier_block otgwl_nb;
33 * otgwl_spinlock is held while the VBUS lock is grabbed or dropped and the
34 * held field is updated to match.
37 static DEFINE_SPINLOCK(otgwl_spinlock);
40 * Only one lock, but since these 3 fields are associated with each other...
45 struct wake_lock wakelock;
50 * VBUS present lock. Also used as a timed lock on charger
51 * connect/disconnect and USB host disconnect, to allow the system
52 * to react to the change in power.
55 static struct otgwl_lock vbus_lock;
57 static void otgwl_hold(struct otgwl_lock *lock)
60 wake_lock(&lock->wakelock);
65 static void otgwl_temporary_hold(struct otgwl_lock *lock)
67 wake_lock_timeout(&lock->wakelock,
68 msecs_to_jiffies(TEMPORARY_HOLD_TIME));
72 static void otgwl_drop(struct otgwl_lock *lock)
75 wake_unlock(&lock->wakelock);
80 static void otgwl_handle_event(unsigned long event)
82 unsigned long irqflags;
84 spin_lock_irqsave(&otgwl_spinlock, irqflags);
87 otgwl_drop(&vbus_lock);
88 spin_unlock_irqrestore(&otgwl_spinlock, irqflags);
94 case USB_EVENT_ENUMERATED:
95 otgwl_hold(&vbus_lock);
100 case USB_EVENT_CHARGER:
101 otgwl_temporary_hold(&vbus_lock);
108 spin_unlock_irqrestore(&otgwl_spinlock, irqflags);
111 static int otgwl_otg_notifications(struct notifier_block *nb,
112 unsigned long event, void *unused)
114 otgwl_handle_event(event);
118 static int set_enabled(const char *val, const struct kernel_param *kp)
120 int rv = param_set_bool(val, kp);
126 otgwl_handle_event(otgwl_xceiv->last_event);
131 static struct kernel_param_ops enabled_param_ops = {
133 .get = param_get_bool,
136 module_param_cb(enabled, &enabled_param_ops, &enabled, 0644);
137 MODULE_PARM_DESC(enabled, "enable wakelock when VBUS present");
139 static int __init otg_wakelock_init(void)
144 phy = usb_get_phy(USB_PHY_TYPE_USB2);
147 pr_err("%s: No USB transceiver found\n", __func__);
152 snprintf(vbus_lock.name, sizeof(vbus_lock.name), "vbus-%s",
153 dev_name(otgwl_xceiv->dev));
154 wake_lock_init(&vbus_lock.wakelock, WAKE_LOCK_SUSPEND,
157 otgwl_nb.notifier_call = otgwl_otg_notifications;
158 ret = usb_register_notifier(otgwl_xceiv, &otgwl_nb);
161 pr_err("%s: usb_register_notifier on transceiver %s"
162 " failed\n", __func__,
163 dev_name(otgwl_xceiv->dev));
165 wake_lock_destroy(&vbus_lock.wakelock);
169 otgwl_handle_event(otgwl_xceiv->last_event);
173 late_initcall(otg_wakelock_init);