usb: musb: Add support for optional VBUS irq to dsps glue layer

We can now configure the PMIC interrupt to provide us VBUS
events. In that case we don't need to constantly poll the
status and can make it optional. This is only wired up
for the mini-B interface on beaglebone.

Note that eventually we should get also the connect status
for the host interface when the am335x internal PM coprocessor
provides us with an IRQ chip. For now, we still need to poll
for the host mode status.

Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Bin Liu <b-liu@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/musb/musb_dsps.c

@@ -118,6 +118,7 @@ struct dsps_glue {
 	struct device *dev;
 	struct platform_device *musb;	/* child musb pdev */
 	const struct dsps_musb_wrapper *wrp; /* wrapper register offsets */
+	int vbus_irq;			/* optional vbus irq */
 	struct timer_list timer;	/* otg_workaround timer */
 	unsigned long last_timer;    /* last timer data for each instance */
 	bool sw_babble_enabled;
@@ -145,6 +146,29 @@ static const struct debugfs_reg32 dsps_musb_regs[] = {
 	{ "mode",		0xe8 },
 };
 
+static void dsps_mod_timer(struct dsps_glue *glue, int wait_ms)
+{
+	int wait;
+
+	if (wait_ms < 0)
+		wait = msecs_to_jiffies(glue->wrp->poll_timeout);
+	else
+		wait = msecs_to_jiffies(wait_ms);
+
+	mod_timer(&glue->timer, jiffies + wait);
+}
+
+/*
+ * If no vbus irq from the PMIC is configured, we need to poll VBUS status.
+ */
+static void dsps_mod_timer_optional(struct dsps_glue *glue)
+{
+	if (glue->vbus_irq)
+		return;
+
+	dsps_mod_timer(glue, -1);
+}
+
 /**
  * dsps_musb_enable - enable interrupts
  */
@@ -167,8 +191,7 @@ static void dsps_musb_enable(struct musb *musb)
 	/* start polling for ID change in dual-role idle mode */
 	if (musb->xceiv->otg->state == OTG_STATE_B_IDLE &&
 			musb->port_mode == MUSB_PORT_MODE_DUAL_ROLE)
-		mod_timer(&glue->timer, jiffies +
-				msecs_to_jiffies(wrp->poll_timeout));
+		dsps_mod_timer(glue, -1);
 }
 
 /**
@@ -198,6 +221,9 @@ static int dsps_check_status(struct musb *musb, void *unused)
 	u8 devctl;
 	int skip_session = 0;
 
+	if (glue->vbus_irq)
+		del_timer(&glue->timer);
+
 	/*
 	 * We poll because DSPS IP's won't expose several OTG-critical
 	 * status change events (from the transceiver) otherwise.
@@ -208,8 +234,7 @@ static int dsps_check_status(struct musb *musb, void *unused)
 
 	switch (musb->xceiv->otg->state) {
 	case OTG_STATE_A_WAIT_VRISE:
-		mod_timer(&glue->timer, jiffies +
-				msecs_to_jiffies(wrp->poll_timeout));
+		dsps_mod_timer_optional(glue);
 		break;
 	case OTG_STATE_A_WAIT_BCON:
 		musb_writeb(musb->mregs, MUSB_DEVCTL, 0);
@@ -218,17 +243,19 @@ static int dsps_check_status(struct musb *musb, void *unused)
 
 	case OTG_STATE_A_IDLE:
 	case OTG_STATE_B_IDLE:
-		if (devctl & MUSB_DEVCTL_BDEVICE) {
-			musb->xceiv->otg->state = OTG_STATE_B_IDLE;
-			MUSB_DEV_MODE(musb);
-		} else {
-			musb->xceiv->otg->state = OTG_STATE_A_IDLE;
-			MUSB_HST_MODE(musb);
+		if (!glue->vbus_irq) {
+			if (devctl & MUSB_DEVCTL_BDEVICE) {
+				musb->xceiv->otg->state = OTG_STATE_B_IDLE;
+				MUSB_DEV_MODE(musb);
+			} else {
+				musb->xceiv->otg->state = OTG_STATE_A_IDLE;
+				MUSB_HST_MODE(musb);
+			}
+			if (!(devctl & MUSB_DEVCTL_SESSION) && !skip_session)
+				musb_writeb(mregs, MUSB_DEVCTL,
+					    MUSB_DEVCTL_SESSION);
 		}
-		if (!(devctl & MUSB_DEVCTL_SESSION) && !skip_session)
-			musb_writeb(mregs, MUSB_DEVCTL, MUSB_DEVCTL_SESSION);
-		mod_timer(&glue->timer, jiffies +
-				msecs_to_jiffies(wrp->poll_timeout));
+		dsps_mod_timer_optional(glue);
 		break;
 	case OTG_STATE_A_WAIT_VFALL:
 		musb->xceiv->otg->state = OTG_STATE_A_WAIT_VRISE;
@@ -331,15 +358,13 @@ static irqreturn_t dsps_interrupt(int irq, void *hci)
 			 */
 			musb->int_usb &= ~MUSB_INTR_VBUSERROR;
 			musb->xceiv->otg->state = OTG_STATE_A_WAIT_VFALL;
-			mod_timer(&glue->timer, jiffies +
-					msecs_to_jiffies(wrp->poll_timeout));
+			dsps_mod_timer_optional(glue);
 			WARNING("VBUS error workaround (delay coming)\n");
 		} else if (drvvbus) {
 			MUSB_HST_MODE(musb);
 			musb->xceiv->otg->default_a = 1;
 			musb->xceiv->otg->state = OTG_STATE_A_WAIT_VRISE;
-			mod_timer(&glue->timer, jiffies +
-				  msecs_to_jiffies(wrp->poll_timeout));
+			dsps_mod_timer_optional(glue);
 		} else {
 			musb->is_active = 0;
 			MUSB_DEV_MODE(musb);
@@ -363,8 +388,7 @@ static irqreturn_t dsps_interrupt(int irq, void *hci)
 	switch (musb->xceiv->otg->state) {
 	case OTG_STATE_B_IDLE:
 	case OTG_STATE_A_WAIT_BCON:
-		mod_timer(&glue->timer, jiffies +
-				msecs_to_jiffies(wrp->poll_timeout));
+		dsps_mod_timer_optional(glue);
 		break;
 	default:
 		break;
@@ -468,8 +492,7 @@ static int dsps_musb_init(struct musb *musb)
 		musb_writeb(musb->mregs, MUSB_BABBLE_CTL, val);
 	}
 
-	mod_timer(&glue->timer, jiffies +
-		  msecs_to_jiffies(glue->wrp->poll_timeout));
+	dsps_mod_timer(glue, -1);
 
 	return dsps_musb_dbg_init(musb, glue);
 }
@@ -765,6 +788,47 @@ err:
 	return ret;
 }
 
+static irqreturn_t dsps_vbus_threaded_irq(int irq, void *priv)
+{
+	struct dsps_glue *glue = priv;
+	struct musb *musb = platform_get_drvdata(glue->musb);
+
+	if (!musb)
+		return IRQ_NONE;
+
+	dev_dbg(glue->dev, "VBUS interrupt\n");
+	dsps_mod_timer(glue, 0);
+
+	return IRQ_HANDLED;
+}
+
+static int dsps_setup_optional_vbus_irq(struct platform_device *pdev,
+					struct dsps_glue *glue)
+{
+	int error;
+
+	glue->vbus_irq = platform_get_irq_byname(pdev, "vbus");
+	if (glue->vbus_irq == -EPROBE_DEFER)
+		return -EPROBE_DEFER;
+
+	if (glue->vbus_irq <= 0) {
+		glue->vbus_irq = 0;
+		return 0;
+	}
+
+	error = devm_request_threaded_irq(glue->dev, glue->vbus_irq,
+					  NULL, dsps_vbus_threaded_irq,
+					  IRQF_ONESHOT,
+					  "vbus", glue);
+	if (error) {
+		glue->vbus_irq = 0;
+		return error;
+	}
+	dev_dbg(glue->dev, "VBUS irq %i configured\n", glue->vbus_irq);
+
+	return 0;
+}
+
 static int dsps_probe(struct platform_device *pdev)
 {
 	const struct of_device_id *match;
@@ -793,6 +857,12 @@ static int dsps_probe(struct platform_device *pdev)
 	glue->dev = &pdev->dev;
 	glue->wrp = wrp;
 
+	if (usb_get_dr_mode(&pdev->dev) == USB_DR_MODE_PERIPHERAL) {
+		ret = dsps_setup_optional_vbus_irq(pdev, glue);
+		if (ret)
+			return ret;
+	}
+
 	platform_set_drvdata(pdev, glue);
 	pm_runtime_enable(&pdev->dev);
 	ret = dsps_create_musb_pdev(glue, pdev);
@@ -903,8 +973,7 @@ static int dsps_resume(struct device *dev)
 	musb_writel(mbase, wrp->rx_mode, glue->context.rx_mode);
 	if (musb->xceiv->otg->state == OTG_STATE_B_IDLE &&
 	    musb->port_mode == MUSB_PORT_MODE_DUAL_ROLE)
-		mod_timer(&glue->timer, jiffies +
-				msecs_to_jiffies(wrp->poll_timeout));
+		dsps_mod_timer(glue, -1);
 
 	return 0;
 }