rtc-m48t59: allow externally mapped ioaddr

Add support for externally mapped ioaddr.  This is required on sparc32
as the ioaddr must be mapped with of_ioremap().

Signed-off-by: Krzysztof Helt <krzysztof.h1@wp.pl>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/rtc/rtc-m48t59.c

diff --git a/drivers/rtc/rtc-m48t59.c b/drivers/rtc/rtc-m48t59.c
index 50f9f10..867c8a7 100644
--- a/drivers/rtc/rtc-m48t59.c
+++ b/drivers/rtc/rtc-m48t59.c
@@ -411,9 +411,14 @@
 	if (!m48t59)
 		return -ENOMEM;
 
-	m48t59->ioaddr = ioremap(res->start, res->end - res->start + 1);
-	if (!m48t59->ioaddr)
-		goto out;
+	m48t59->ioaddr = pdata->ioaddr;
+
+	if (!m48t59->ioaddr) {
+		/* ioaddr not mapped externally */
+		m48t59->ioaddr = ioremap(res->start, res->end - res->start + 1);
+		if (!m48t59->ioaddr)
+			goto out;
+	}
 
 	/* Try to get irq number. We also can work in
 	 * the mode without IRQ.
@@ -481,11 +486,12 @@
 static int __devexit m48t59_rtc_remove(struct platform_device *pdev)
 {
 	struct m48t59_private *m48t59 = platform_get_drvdata(pdev);
+	struct m48t59_plat_data *pdata = pdev->dev.platform_data;
 
 	sysfs_remove_bin_file(&pdev->dev.kobj, &m48t59_nvram_attr);
 	if (!IS_ERR(m48t59->rtc))
 		rtc_device_unregister(m48t59->rtc);
-	if (m48t59->ioaddr)
+	if (m48t59->ioaddr && !pdata->ioaddr)
 		iounmap(m48t59->ioaddr);
 	if (m48t59->irq != NO_IRQ)
 		free_irq(m48t59->irq, &pdev->dev);

include/linux/rtc/m48t59.h

diff --git a/include/linux/rtc/m48t59.h b/include/linux/rtc/m48t59.h
index 4179850..6fc9614 100644
--- a/include/linux/rtc/m48t59.h
+++ b/include/linux/rtc/m48t59.h
@@ -55,6 +55,8 @@
 
 	int type; /* RTC model */
 
+	/* ioaddr mapped externally */
+	void __iomem *ioaddr;
 	/* offset to RTC registers, automatically set according to the type */
 	unsigned int offset;
 };