usb: gadget: mv_udc: add clock gating support

This patch is going to support clock gating when vbus detection is
posible. Clock and phy will be on only when usb gadget is used(vbus valid).

Signed-off-by: Neil Zhang <zhangwm@marvell.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

drivers/usb/gadget/mv_udc.h

@@ -209,7 +209,12 @@ struct mv_udc {
 				vbus_active:1,
 				remote_wakeup:1,
 				softconnected:1,
-				force_fs:1;
+				force_fs:1,
+				clock_gating:1,
+				active:1;
+
+	struct work_struct	vbus_work;
+	struct workqueue_struct *qwork;
 
 	struct mv_usb_platform_data     *pdata;
 

drivers/usb/gadget/mv_udc_core.c

@@ -67,6 +67,7 @@ static struct mv_udc	*the_controller;
 int mv_usb_otgsc;
 
 static void nuke(struct mv_ep *ep, int status);
+static void stop_activity(struct mv_udc *udc, struct usb_gadget_driver *driver);
 
 /* for endpoint 0 operations */
 static const struct usb_endpoint_descriptor mv_ep0_desc = {
@@ -1133,6 +1134,40 @@ static int udc_reset(struct mv_udc *udc)
 	return 0;
 }
 
+static int mv_udc_enable(struct mv_udc *udc)
+{
+	int retval;
+
+	if (udc->clock_gating == 0 || udc->active)
+		return 0;
+
+	dev_dbg(&udc->dev->dev, "enable udc\n");
+	udc_clock_enable(udc);
+	if (udc->pdata->phy_init) {
+		retval = udc->pdata->phy_init(udc->phy_regs);
+		if (retval) {
+			dev_err(&udc->dev->dev,
+				"init phy error %d\n", retval);
+			udc_clock_disable(udc);
+			return retval;
+		}
+	}
+	udc->active = 1;
+
+	return 0;
+}
+
+static void mv_udc_disable(struct mv_udc *udc)
+{
+	if (udc->clock_gating && udc->active) {
+		dev_dbg(&udc->dev->dev, "disable udc\n");
+		if (udc->pdata->phy_deinit)
+			udc->pdata->phy_deinit(udc->phy_regs);
+		udc_clock_disable(udc);
+		udc->active = 0;
+	}
+}
+
 static int mv_udc_get_frame(struct usb_gadget *gadget)
 {
 	struct mv_udc *udc;
@@ -1168,22 +1203,68 @@ static int mv_udc_wakeup(struct usb_gadget *gadget)
 	return 0;
 }
 
+static int mv_udc_vbus_session(struct usb_gadget *gadget, int is_active)
+{
+	struct mv_udc *udc;
+	unsigned long flags;
+	int retval = 0;
+
+	udc = container_of(gadget, struct mv_udc, gadget);
+	spin_lock_irqsave(&udc->lock, flags);
+
+	dev_dbg(&udc->dev->dev, "%s: softconnect %d, vbus_active %d\n",
+		__func__, udc->softconnect, udc->vbus_active);
+
+	udc->vbus_active = (is_active != 0);
+	if (udc->driver && udc->softconnect && udc->vbus_active) {
+		retval = mv_udc_enable(udc);
+		if (retval == 0) {
+			/* Clock is disabled, need re-init registers */
+			udc_reset(udc);
+			ep0_reset(udc);
+			udc_start(udc);
+		}
+	} else if (udc->driver && udc->softconnect) {
+		/* stop all the transfer in queue*/
+		stop_activity(udc, udc->driver);
+		udc_stop(udc);
+		mv_udc_disable(udc);
+	}
+
+	spin_unlock_irqrestore(&udc->lock, flags);
+	return retval;
+}
+
 static int mv_udc_pullup(struct usb_gadget *gadget, int is_on)
 {
 	struct mv_udc *udc;
 	unsigned long flags;
+	int retval = 0;
 
 	udc = container_of(gadget, struct mv_udc, gadget);
 	spin_lock_irqsave(&udc->lock, flags);
 
+	dev_dbg(&udc->dev->dev, "%s: softconnect %d, vbus_active %d\n",
+			__func__, udc->softconnect, udc->vbus_active);
+
 	udc->softconnect = (is_on != 0);
-	if (udc->driver && udc->softconnect)
-		udc_start(udc);
-	else
+	if (udc->driver && udc->softconnect && udc->vbus_active) {
+		retval = mv_udc_enable(udc);
+		if (retval == 0) {
+			/* Clock is disabled, need re-init registers */
+			udc_reset(udc);
+			ep0_reset(udc);
+			udc_start(udc);
+		}
+	} else if (udc->driver && udc->vbus_active) {
+		/* stop all the transfer in queue*/
+		stop_activity(udc, udc->driver);
 		udc_stop(udc);
+		mv_udc_disable(udc);
+	}
 
 	spin_unlock_irqrestore(&udc->lock, flags);
-	return 0;
+	return retval;
 }
 
 static int mv_udc_start(struct usb_gadget_driver *driver,
@@ -1198,6 +1279,9 @@ static const struct usb_gadget_ops mv_ops = {
 	/* tries to wake up the host connected to this gadget */
 	.wakeup		= mv_udc_wakeup,
 
+	/* notify controller that VBUS is powered or not */
+	.vbus_session	= mv_udc_vbus_session,
+
 	/* D+ pullup, software-controlled connect/disconnect to USB host */
 	.pullup		= mv_udc_pullup,
 	.start		= mv_udc_start,
@@ -1310,7 +1394,7 @@ static int mv_udc_start(struct usb_gadget_driver *driver,
 
 	udc->usb_state = USB_STATE_ATTACHED;
 	udc->ep0_state = WAIT_FOR_SETUP;
-	udc->ep0_dir = USB_DIR_OUT;
+	udc->ep0_dir = EP_DIR_OUT;
 
 	spin_unlock_irqrestore(&udc->lock, flags);
 
@@ -1322,9 +1406,13 @@ static int mv_udc_start(struct usb_gadget_driver *driver,
 		udc->gadget.dev.driver = NULL;
 		return retval;
 	}
-	udc_reset(udc);
-	ep0_reset(udc);
-	udc_start(udc);
+
+	/* pullup is always on */
+	mv_udc_pullup(&udc->gadget, 1);
+
+	/* When boot with cable attached, there will be no vbus irq occurred */
+	if (udc->qwork)
+		queue_work(udc->qwork, &udc->vbus_work);
 
 	return 0;
 }
@@ -1337,13 +1425,16 @@ static int mv_udc_stop(struct usb_gadget_driver *driver)
 	if (!udc)
 		return -ENODEV;
 
-	udc_stop(udc);
-
 	spin_lock_irqsave(&udc->lock, flags);
 
+	mv_udc_enable(udc);
+	udc_stop(udc);
+
 	/* stop all usb activities */
 	udc->gadget.speed = USB_SPEED_UNKNOWN;
 	stop_activity(udc, driver);
+	mv_udc_disable(udc);
+
 	spin_unlock_irqrestore(&udc->lock, flags);
 
 	/* unbind gadget driver */
@@ -1969,6 +2060,35 @@ static irqreturn_t mv_udc_irq(int irq, void *dev)
 	return IRQ_HANDLED;
 }
 
+static irqreturn_t mv_udc_vbus_irq(int irq, void *dev)
+{
+	struct mv_udc *udc = (struct mv_udc *)dev;
+
+	/* polling VBUS and init phy may cause too much time*/
+	if (udc->qwork)
+		queue_work(udc->qwork, &udc->vbus_work);
+
+	return IRQ_HANDLED;
+}
+
+static void mv_udc_vbus_work(struct work_struct *work)
+{
+	struct mv_udc *udc;
+	unsigned int vbus;
+
+	udc = container_of(work, struct mv_udc, vbus_work);
+	if (!udc->pdata->vbus)
+		return;
+
+	vbus = udc->pdata->vbus->poll();
+	dev_info(&udc->dev->dev, "vbus is %d\n", vbus);
+
+	if (vbus == VBUS_HIGH)
+		mv_udc_vbus_session(&udc->gadget, 1);
+	else if (vbus == VBUS_LOW)
+		mv_udc_vbus_session(&udc->gadget, 0);
+}
+
 /* release device structure */
 static void gadget_release(struct device *_dev)
 {
@@ -1984,6 +2104,14 @@ static int __devexit mv_udc_remove(struct platform_device *dev)
 
 	usb_del_gadget_udc(&udc->gadget);
 
+	if (udc->qwork) {
+		flush_workqueue(udc->qwork);
+		destroy_workqueue(udc->qwork);
+	}
+
+	if (udc->pdata && udc->pdata->vbus && udc->clock_gating)
+		free_irq(udc->pdata->vbus->irq, &dev->dev);
+
 	/* free memory allocated in probe */
 	if (udc->dtd_pool)
 		dma_pool_destroy(udc->dtd_pool);
@@ -1997,6 +2125,8 @@ static int __devexit mv_udc_remove(struct platform_device *dev)
 	if (udc->irq)
 		free_irq(udc->irq, &dev->dev);
 
+	mv_udc_disable(udc);
+
 	if (udc->cap_regs)
 		iounmap(udc->cap_regs);
 	udc->cap_regs = NULL;
@@ -2197,13 +2327,52 @@ static int __devinit mv_udc_probe(struct platform_device *dev)
 
 	eps_init(udc);
 
+	/* VBUS detect: we can disable/enable clock on demand.*/
+	if (pdata->vbus) {
+		udc->clock_gating = 1;
+		retval = request_threaded_irq(pdata->vbus->irq, NULL,
+				mv_udc_vbus_irq, IRQF_ONESHOT, "vbus", udc);
+		if (retval) {
+			dev_info(&dev->dev,
+				"Can not request irq for VBUS, "
+				"disable clock gating\n");
+			udc->clock_gating = 0;
+		}
+
+		udc->qwork = create_singlethread_workqueue("mv_udc_queue");
+		if (!udc->qwork) {
+			dev_err(&dev->dev, "cannot create workqueue\n");
+			retval = -ENOMEM;
+			goto err_unregister;
+		}
+
+		INIT_WORK(&udc->vbus_work, mv_udc_vbus_work);
+	}
+
+	/*
+	 * When clock gating is supported, we can disable clk and phy.
+	 * If not, it means that VBUS detection is not supported, we
+	 * have to enable vbus active all the time to let controller work.
+	 */
+	if (udc->clock_gating) {
+		if (udc->pdata->phy_deinit)
+			udc->pdata->phy_deinit(udc->phy_regs);
+		udc_clock_disable(udc);
+	} else
+		udc->vbus_active = 1;
+
 	retval = usb_add_gadget_udc(&dev->dev, &udc->gadget);
 	if (retval)
 		goto err_unregister;
 
+	dev_info(&dev->dev, "successful probe UDC device %s clock gating.\n",
+		udc->clock_gating ? "with" : "without");
+
 	return 0;
 
 err_unregister:
+	if (udc->pdata && udc->pdata->vbus && udc->clock_gating)
+		free_irq(pdata->vbus->irq, &dev->dev);
 	device_unregister(&udc->gadget.dev);
 err_free_irq:
 	free_irq(udc->irq, &dev->dev);