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Subject[next, PATCH 6/6] usb: mtu3: fix warning of sleep in atomic context in notifier callback
Date
The notifier callbacks of extcon are called in atomic context, but the
callbacks will call regulator_enable()/regulator_disable() which may
sleep caused by mutex, so use work queue to call the sleep functions.

Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
---
drivers/usb/mtu3/mtu3.h | 11 ++++++++++-
drivers/usb/mtu3/mtu3_dr.c | 44 ++++++++++++++++++++++++++++++++++++--------
2 files changed, 46 insertions(+), 9 deletions(-)

diff --git a/drivers/usb/mtu3/mtu3.h b/drivers/usb/mtu3/mtu3.h
index a56fee0..87823ac 100644
--- a/drivers/usb/mtu3/mtu3.h
+++ b/drivers/usb/mtu3/mtu3.h
@@ -196,7 +196,12 @@ struct mtu3_gpd_ring {
* @vbus: vbus 5V used by host mode
* @edev: external connector used to detect vbus and iddig changes
* @vbus_nb: notifier for vbus detection
-* @vbus_nb: notifier for iddig(idpin) detection
+* @vbus_work : work of vbus detection notifier, used to avoid sleep in
+* notifier callback which is atomic context
+* @vbus_event : event of vbus detecion notifier
+* @id_nb : notifier for iddig(idpin) detection
+* @id_work : work of iddig detection notifier
+* @id_event : event of iddig detecion notifier
* @is_u3_drd: whether port0 supports usb3.0 dual-role device or not
* @manual_drd_enabled: it's true when supports dual-role device by debugfs
* to switch host/device modes depending on user input.
@@ -205,7 +210,11 @@ struct otg_switch_mtk {
struct regulator *vbus;
struct extcon_dev *edev;
struct notifier_block vbus_nb;
+ struct work_struct vbus_work;
+ unsigned long vbus_event;
struct notifier_block id_nb;
+ struct work_struct id_work;
+ unsigned long id_event;
bool is_u3_drd;
bool manual_drd_enabled;
};
diff --git a/drivers/usb/mtu3/mtu3_dr.c b/drivers/usb/mtu3/mtu3_dr.c
index 80083e0..8c3bbf7 100644
--- a/drivers/usb/mtu3/mtu3_dr.c
+++ b/drivers/usb/mtu3/mtu3_dr.c
@@ -174,16 +174,40 @@ static void ssusb_set_mailbox(struct otg_switch_mtk *otg_sx,
}
}

-static int ssusb_id_notifier(struct notifier_block *nb,
- unsigned long event, void *ptr)
+static void ssusb_id_work(struct work_struct *work)
{
struct otg_switch_mtk *otg_sx =
- container_of(nb, struct otg_switch_mtk, id_nb);
+ container_of(work, struct otg_switch_mtk, id_work);

- if (event)
+ if (otg_sx->id_event)
ssusb_set_mailbox(otg_sx, MTU3_ID_GROUND);
else
ssusb_set_mailbox(otg_sx, MTU3_ID_FLOAT);
+}
+
+static void ssusb_vbus_work(struct work_struct *work)
+{
+ struct otg_switch_mtk *otg_sx =
+ container_of(work, struct otg_switch_mtk, vbus_work);
+
+ if (otg_sx->vbus_event)
+ ssusb_set_mailbox(otg_sx, MTU3_VBUS_VALID);
+ else
+ ssusb_set_mailbox(otg_sx, MTU3_VBUS_OFF);
+}
+
+/*
+ * @ssusb_id_notifier is called in atomic context, but @ssusb_set_mailbox
+ * may sleep, so use work queue here
+ */
+static int ssusb_id_notifier(struct notifier_block *nb,
+ unsigned long event, void *ptr)
+{
+ struct otg_switch_mtk *otg_sx =
+ container_of(nb, struct otg_switch_mtk, id_nb);
+
+ otg_sx->id_event = event;
+ schedule_work(&otg_sx->id_work);

return NOTIFY_DONE;
}
@@ -194,10 +218,8 @@ static int ssusb_vbus_notifier(struct notifier_block *nb,
struct otg_switch_mtk *otg_sx =
container_of(nb, struct otg_switch_mtk, vbus_nb);

- if (event)
- ssusb_set_mailbox(otg_sx, MTU3_VBUS_VALID);
- else
- ssusb_set_mailbox(otg_sx, MTU3_VBUS_OFF);
+ otg_sx->vbus_event = event;
+ schedule_work(&otg_sx->vbus_work);

return NOTIFY_DONE;
}
@@ -398,6 +420,9 @@ int ssusb_otg_switch_init(struct ssusb_mtk *ssusb)
{
struct otg_switch_mtk *otg_sx = &ssusb->otg_switch;

+ INIT_WORK(&otg_sx->id_work, ssusb_id_work);
+ INIT_WORK(&otg_sx->vbus_work, ssusb_vbus_work);
+
if (otg_sx->manual_drd_enabled)
ssusb_debugfs_init(ssusb);
else
@@ -412,4 +437,7 @@ void ssusb_otg_switch_exit(struct ssusb_mtk *ssusb)

if (otg_sx->manual_drd_enabled)
ssusb_debugfs_exit(ssusb);
+
+ cancel_work_sync(&otg_sx->id_work);
+ cancel_work_sync(&otg_sx->vbus_work);
}
--
1.9.1
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