USB: OTG: Use work_queue in set_vbus for TWL6030 transciever

With this commit: cccad6d4b103e53fb3d1fc1467f654ecb572d047
usb: otg: notifier: switch to atomic notifier

Following dumps are observed on attach/detach for MUSB HOST
mode and on a detach for MUSB Device mode.

BUG: sleeping function called from invalid context at kernel/mutex.c:85
where, the source is:
twl6030_usb_irq
->atomic_notifier_call_chain
 ->musb_otg_notifications
  ->twl6030_set_vbus
   ->twl_i2c_write_u8
    ->mutex_lock

This patch moves the i2c writes in set_vbus function to a
work-queue thereby avoiding I2C writes in atomic context.

Tested HOST and Device mode functionality on OMAP4460

Signed-off-by: Moiz Sonasath <m-sonasath@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/usb/otg/twl6030-usb.c b/drivers/usb/otg/twl6030-usb.c
index cfb5aa72b1962916d87c6c873521d05112bda930..b4d2c0972b3df77b67db8efb5cb0838e4bc26097 100644 (file)
--- a/drivers/usb/otg/twl6030-usb.c
+++ b/drivers/usb/otg/twl6030-usb.c
@@ -95,11 +95,15 @@ struct twl6030_usb {
 
        struct regulator                *usb3v3;
 
+       /* used to set vbus, in atomic path */
+       struct work_struct      set_vbus_work;
+
        int                     irq1;
        int                     irq2;
        u8                      linkstat;
        u8                      asleep;
        bool                    irq_enabled;
+       bool                    vbus_enable;
        unsigned long           features;
 };
 
@@ -370,20 +374,31 @@ static int twl6030_enable_irq(struct otg_transceiver *x)
        return 0;
 }
 
-static int twl6030_set_vbus(struct otg_transceiver *x, bool enabled)
+static void otg_set_vbus_work(struct work_struct *data)
 {
-       struct twl6030_usb *twl = xceiv_to_twl(x);
+       struct twl6030_usb *twl = container_of(data, struct twl6030_usb,
+                                                               set_vbus_work);
 
        /*
         * Start driving VBUS. Set OPA_MODE bit in CHARGERUSB_CTRL1
         * register. This enables boost mode.
         */
-       if (enabled)
+
+       if (twl->vbus_enable)
                twl6030_writeb(twl, TWL_MODULE_MAIN_CHARGE , 0x40,
-                                               CHARGERUSB_CTRL1);
-        else
+                                                       CHARGERUSB_CTRL1);
+       else
                twl6030_writeb(twl, TWL_MODULE_MAIN_CHARGE , 0x00,
-                                               CHARGERUSB_CTRL1);
+                                                       CHARGERUSB_CTRL1);
+}
+
+static int twl6030_set_vbus(struct otg_transceiver *x, bool enabled)
+{
+       struct twl6030_usb *twl = xceiv_to_twl(x);
+
+       twl->vbus_enable = enabled;
+       schedule_work(&twl->set_vbus_work);
+
        return 0;
 }
 
@@ -444,6 +459,8 @@ static int __devinit twl6030_usb_probe(struct platform_device *pdev)
 
        ATOMIC_INIT_NOTIFIER_HEAD(&twl->otg.notifier);
 
+       INIT_WORK(&twl->set_vbus_work, otg_set_vbus_work);
+
        twl->irq_enabled = true;
        status = request_threaded_irq(twl->irq1, NULL, twl6030_usbotg_irq,
                        IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING,
@@ -494,6 +511,7 @@ static int __exit twl6030_usb_remove(struct platform_device *pdev)
        regulator_put(twl->usb3v3);
        pdata->phy_exit(twl->dev);
        device_remove_file(twl->dev, &dev_attr_vbus);
+       cancel_work_sync(&twl->set_vbus_work);
        kfree(twl);
 
        return 0;