[RFC v1 1/2] USB: OTG: Hold wakeupsource when VBUS present
From: Kiran Kumar Raparthy
Date: Thu Aug 28 2014 - 05:55:41 EST
From: Todd Poynor <toddpoynor@xxxxxxxxxx>
USB: OTG: Hold wakeupsource when VBUS present
Purpose of this is to prevent the system to enter into
suspend state from USB peripheral traffic by hodling a
wakeupsource when USB(otg) is connected and enumerated
in peripheral mode(say adb).
Disabled by default, can enable with:
echo Y > /sys/module/otg_wakeupsource/parameters/enabled
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>
Cc: Arve Hjøå<arve@xxxxxxxxxxx>
Cc: Benoit Goby <benoit@xxxxxxxxxxx>
Signed-off-by: Todd Poynor <toddpoynor@xxxxxxxxxx>
[kiran: Added context to commit message.
Included build fix from Benoit Goby and Arve Hjøå
Removed lock->held field in driver as this mechanism is
provided in wakeupsource driver.
wakelock(wl) terminology replaced with wakeup_source(ws).
changed to disabled by default from "enable by default".
sys entry(module param) field modified to otg_wakeupsource.
included Todd's refactoring logic.
Introduced get_phy_hook to handle otgws_xceiv per-PHY.
otgws_nb moved to otg_wakeupsource_init function.
__pm_stay_awake and __pm_relax called directly from the main.
code instead of calling them via otgws_grab,otgws_drop.
modified Kconfig help text]
Signed-off-by: Kiran Raparthy <kiran.kumar@xxxxxxxxxx>
---
drivers/usb/phy/Kconfig | 8 +++
drivers/usb/phy/Makefile | 1 +
drivers/usb/phy/otg-wakeupsource.c | 144 +++++++++++++++++++++++++++++++++++++
3 files changed, 153 insertions(+)
create mode 100644 drivers/usb/phy/otg-wakeupsource.c
diff --git a/drivers/usb/phy/Kconfig b/drivers/usb/phy/Kconfig
index e253fa0..d9ddd85 100644
--- a/drivers/usb/phy/Kconfig
+++ b/drivers/usb/phy/Kconfig
@@ -6,6 +6,14 @@ menu "USB Physical Layer drivers"
config USB_PHY
def_bool n
+config USB_OTG_WAKEUPSOURCE
+ bool "Hold wakeupsource when USB is enumerated in peripheral mode"
+ depends on PM_SLEEP
+ select USB_PHY
+ help
+ Prevent the system going into automatic suspend while
+ it is attached as a USB peripheral by holding a wakeupsource.
+
#
# USB Transceiver Drivers
#
diff --git a/drivers/usb/phy/Makefile b/drivers/usb/phy/Makefile
index 24a9133..ca2fbaf 100644
--- a/drivers/usb/phy/Makefile
+++ b/drivers/usb/phy/Makefile
@@ -3,6 +3,7 @@
#
obj-$(CONFIG_USB_PHY) += phy.o
obj-$(CONFIG_OF) += of.o
+obj-$(CONFIG_USB_OTG_WAKEUPSOURCE) += otg-wakeupsource.o
# transceiver drivers, keep the list sorted
diff --git a/drivers/usb/phy/otg-wakeupsource.c b/drivers/usb/phy/otg-wakeupsource.c
new file mode 100644
index 0000000..7c838d1
--- /dev/null
+++ b/drivers/usb/phy/otg-wakeupsource.c
@@ -0,0 +1,144 @@
+/*
+ * otg-wakeupsource.c
+ *
+ * Copyright (C) 2011 Google, Inc.
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/device.h>
+#include <linux/module.h>
+#include <linux/notifier.h>
+#include <linux/pm_wakeup.h>
+#include <linux/spinlock.h>
+#include <linux/usb/otg.h>
+
+bool enabled = false;
+
+static DEFINE_SPINLOCK(otgws_spinlock);
+static struct usb_phy *get_phy_hook(void);
+
+/* Only one lock, but since these 2 fields are associated with each other... */
+
+struct otgws_lock {
+ char name[40];
+ struct wakeup_source wsource;
+};
+
+/* VBUS present lock */
+
+static struct otgws_lock vbus_lock;
+
+static void otgws_handle_event(unsigned long event)
+{
+ unsigned long irqflags;
+
+ spin_lock_irqsave(&otgws_spinlock, irqflags);
+
+ if (!enabled) {
+ __pm_relax(&vbus_lock.wsource);
+ spin_unlock_irqrestore(&otgws_spinlock, irqflags);
+ return;
+ }
+
+ switch (event) {
+ case USB_EVENT_VBUS:
+ case USB_EVENT_ENUMERATED:
+ __pm_stay_awake(&vbus_lock.wsource);
+ break;
+
+ case USB_EVENT_NONE:
+ case USB_EVENT_ID:
+ case USB_EVENT_CHARGER:
+ __pm_relax(&vbus_lock.wsource);
+ break;
+
+ default:
+ break;
+ }
+
+ spin_unlock_irqrestore(&otgws_spinlock, irqflags);
+}
+static struct usb_phy *get_phy_hook(void)
+{
+ struct usb_phy *phy;
+
+ phy = usb_get_phy(USB_PHY_TYPE_USB2);
+
+ if (IS_ERR(phy)) {
+ pr_err("%s: No OTG transceiver found\n", __func__);
+ return NULL;
+ }
+
+ return phy;
+}
+static int otgws_otg_notifications(struct notifier_block *nb,
+ unsigned long event, void *unused)
+{
+ otgws_handle_event(event);
+ return NOTIFY_OK;
+}
+
+static int set_enabled(const char *val, const struct kernel_param *kp)
+{
+ int rv = param_set_bool(val, kp);
+ static struct usb_phy *otgws_xceiv;
+
+ if (rv)
+ return rv;
+
+ otgws_xceiv = get_phy_hook();
+
+ if (otgws_xceiv)
+ otgws_handle_event(otgws_xceiv->last_event);
+
+ return 0;
+}
+
+static struct kernel_param_ops enabled_param_ops = {
+ .set = set_enabled,
+ .get = param_get_bool,
+};
+
+module_param_cb(enabled, &enabled_param_ops, &enabled, 0644);
+MODULE_PARM_DESC(enabled, "Hold wakeupsource when VBUS present");
+
+static int __init otg_wakeupsource_init(void)
+{
+ int ret;
+ static struct notifier_block otgws_nb;
+ static struct usb_phy *otgws_xceiv;
+
+ otgws_xceiv = get_phy_hook();
+
+ if (NULL == otgws_xceiv)
+ return PTR_ERR(otgws_xceiv);
+
+ snprintf(vbus_lock.name, sizeof(vbus_lock.name), "vbus-%s",
+ dev_name(otgws_xceiv->dev));
+ wakeup_source_init(&vbus_lock.wsource, vbus_lock.name);
+
+ otgws_nb.notifier_call = otgws_otg_notifications;
+ ret = usb_register_notifier(otgws_xceiv, &otgws_nb);
+
+ if (ret) {
+ pr_err("%s: usb_register_notifier on transceiver %s failed\n",
+ __func__, dev_name(otgws_xceiv->dev));
+ otgws_xceiv = NULL;
+ wakeup_source_trash(&vbus_lock.wsource);
+ return ret;
+ }
+
+ return 0;
+}
+
+late_initcall(otg_wakeupsource_init);
--
1.8.2.1
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