usb: dwc3: omap: use request_threaded_irq()

We intend to share this interrupt with the OTG driver an to ensure
that irqflags match for the shared interrupt handlers we use
request_threaded_irq()

If we don't use request_treaded_irq() then forced threaded irq will
set IRQF_ONESHOT and this won't match with the OTG IRQ handler's
IRQ flags.

NOTE: OTG IRQ handler is yet to be added. This is a preparatory step.
Signed-off-by: Roger Quadros <rogerq@ti.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>

drivers/usb/dwc3/dwc3-omap.c

@@ -165,7 +165,7 @@ static void dwc3_omap_write_utmi_ctrl(struct dwc3_omap *omap, u32 value)
 
 static u32 dwc3_omap_read_irq0_status(struct dwc3_omap *omap)
 {
-	return dwc3_omap_readl(omap->base, USBOTGSS_IRQSTATUS_0 -
+	return dwc3_omap_readl(omap->base, USBOTGSS_IRQSTATUS_RAW_0 -
 						omap->irq0_offset);
 }
 
@@ -178,7 +178,7 @@ static void dwc3_omap_write_irq0_status(struct dwc3_omap *omap, u32 value)
 
 static u32 dwc3_omap_read_irqmisc_status(struct dwc3_omap *omap)
 {
-	return dwc3_omap_readl(omap->base, USBOTGSS_IRQSTATUS_MISC +
+	return dwc3_omap_readl(omap->base, USBOTGSS_IRQSTATUS_RAW_MISC +
 						omap->irqmisc_offset);
 }
 
@@ -268,19 +268,38 @@ static void dwc3_omap_set_mailbox(struct dwc3_omap *omap,
 	}
 }
 
+static void dwc3_omap_enable_irqs(struct dwc3_omap *omap);
+static void dwc3_omap_disable_irqs(struct dwc3_omap *omap);
+
 static irqreturn_t dwc3_omap_interrupt(int irq, void *_omap)
+{
+	struct dwc3_omap	*omap = _omap;
+
+	if (dwc3_omap_read_irqmisc_status(omap) ||
+	    dwc3_omap_read_irq0_status(omap)) {
+		/* mask irqs */
+		dwc3_omap_disable_irqs(omap);
+		return IRQ_WAKE_THREAD;
+	}
+
+	return IRQ_NONE;
+}
+
+static irqreturn_t dwc3_omap_interrupt_thread(int irq, void *_omap)
 {
 	struct dwc3_omap	*omap = _omap;
 	u32			reg;
 
+	/* clear irq status flags */
 	reg = dwc3_omap_read_irqmisc_status(omap);
-
 	dwc3_omap_write_irqmisc_status(omap, reg);
 
 	reg = dwc3_omap_read_irq0_status(omap);
-
 	dwc3_omap_write_irq0_status(omap, reg);
 
+	/* unmask irqs */
+	dwc3_omap_enable_irqs(omap);
+
 	return IRQ_HANDLED;
 }
 
@@ -497,7 +516,8 @@ static int dwc3_omap_probe(struct platform_device *pdev)
 	/* check the DMA Status */
 	reg = dwc3_omap_readl(omap->base, USBOTGSS_SYSCONFIG);
 
-	ret = devm_request_irq(dev, omap->irq, dwc3_omap_interrupt, 0,
+	ret = devm_request_threaded_irq(dev, omap->irq, dwc3_omap_interrupt,
+					dwc3_omap_interrupt_thread, 0,
 					"dwc3-omap", omap);
 	if (ret) {
 		dev_err(dev, "failed to request IRQ #%d --> %d\n",