ARM: at91: fix rtc-at91sam9 irq issue due to sparse irq support

AT91_ID_SYS as virq is incorrect because of spare irq support which
introduces NR_IRQS_LEGACY offset. It modifies rtc-at91sam9 driver in
order to get irq from resources.

Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
diff --git a/drivers/rtc/rtc-at91sam9.c b/drivers/rtc/rtc-at91sam9.c
index 8318689..1dd61f4 100644
--- a/drivers/rtc/rtc-at91sam9.c
+++ b/drivers/rtc/rtc-at91sam9.c
@@ -58,6 +58,7 @@
 	struct rtc_device	*rtcdev;
 	u32			imr;
 	void __iomem		*gpbr;
+	int 			irq;
 };
 
 #define rtt_readl(rtc, field) \
@@ -292,7 +293,7 @@
 {
 	struct resource	*r, *r_gpbr;
 	struct sam9_rtc	*rtc;
-	int		ret;
+	int		ret, irq;
 	u32		mr;
 
 	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
@@ -302,10 +303,18 @@
 		return -ENODEV;
 	}
 
+	irq = platform_get_irq(pdev, 0);
+	if (irq < 0) {
+		dev_err(&pdev->dev, "failed to get interrupt resource\n");
+		return irq;
+	}
+
 	rtc = kzalloc(sizeof *rtc, GFP_KERNEL);
 	if (!rtc)
 		return -ENOMEM;
 
+	rtc->irq = irq;
+
 	/* platform setup code should have handled this; sigh */
 	if (!device_can_wakeup(&pdev->dev))
 		device_init_wakeup(&pdev->dev, 1);
@@ -345,11 +354,10 @@
 	}
 
 	/* register irq handler after we know what name we'll use */
-	ret = request_irq(AT91_ID_SYS, at91_rtc_interrupt,
-				IRQF_SHARED,
+	ret = request_irq(rtc->irq, at91_rtc_interrupt, IRQF_SHARED,
 				dev_name(&rtc->rtcdev->dev), rtc);
 	if (ret) {
-		dev_dbg(&pdev->dev, "can't share IRQ %d?\n", AT91_ID_SYS);
+		dev_dbg(&pdev->dev, "can't share IRQ %d?\n", rtc->irq);
 		rtc_device_unregister(rtc->rtcdev);
 		goto fail_register;
 	}
@@ -386,7 +394,7 @@
 
 	/* disable all interrupts */
 	rtt_writel(rtc, MR, mr & ~(AT91_RTT_ALMIEN | AT91_RTT_RTTINCIEN));
-	free_irq(AT91_ID_SYS, rtc);
+	free_irq(rtc->irq, rtc);
 
 	rtc_device_unregister(rtc->rtcdev);
 
@@ -423,7 +431,7 @@
 	rtc->imr = mr & (AT91_RTT_ALMIEN | AT91_RTT_RTTINCIEN);
 	if (rtc->imr) {
 		if (device_may_wakeup(&pdev->dev) && (mr & AT91_RTT_ALMIEN)) {
-			enable_irq_wake(AT91_ID_SYS);
+			enable_irq_wake(rtc->irq);
 			/* don't let RTTINC cause wakeups */
 			if (mr & AT91_RTT_RTTINCIEN)
 				rtt_writel(rtc, MR, mr & ~AT91_RTT_RTTINCIEN);
@@ -441,7 +449,7 @@
 
 	if (rtc->imr) {
 		if (device_may_wakeup(&pdev->dev))
-			disable_irq_wake(AT91_ID_SYS);
+			disable_irq_wake(rtc->irq);
 		mr = rtt_readl(rtc, MR);
 		rtt_writel(rtc, MR, mr | rtc->imr);
 	}