watchdog: imx2_wdt: convert to use regmap API.

This watchdog driver will be working on IMX2+, Vybrid, LS1, LS2+
platforms, and will be in different endianness mode in those SoCs:

SoCs         CPU endian mode      WDT endian mode
------------------------------------------------
IMX2+            LE                    LE
Vybird           LE                    LE
LS1              LE                    BE
LS2              LE                    LE

Other possible SoCs:
SoCs         CPU endian mode      WDT endian mode
------------------------------------------------
Soc1             BE                    BE
Soc2             BE                    LE

And also the watchdog's registers will be 32-bits for some versions,
and though it is 16-bits in IMX2+, Vybird and LS+.

Using the regmap APIs, could be more easy to support different
endianness and also more easy to support 32-bits version...
Signed-off-by: Xiubo Li <Li.Xiubo@freescale.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Acked-by: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

drivers/watchdog/Kconfig

@@ -378,6 +378,7 @@ config MAX63XX_WATCHDOG
 config IMX2_WDT
 	tristate "IMX2+ Watchdog"
 	depends on ARCH_MXC
+	select REGMAP_MMIO
 	help
 	  This is the driver for the hardware watchdog
 	  on the Freescale IMX2 and later processors.

drivers/watchdog/imx2_wdt.c

@@ -31,6 +31,7 @@
 #include <linux/module.h>
 #include <linux/moduleparam.h>
 #include <linux/platform_device.h>
+#include <linux/regmap.h>
 #include <linux/timer.h>
 #include <linux/uaccess.h>
 #include <linux/watchdog.h>
@@ -61,7 +62,7 @@
 
 static struct {
 	struct clk *clk;
-	void __iomem *base;
+	struct regmap *regmap;
 	unsigned timeout;
 	unsigned long status;
 	struct timer_list timer;	/* Pings the watchdog when closed */
@@ -87,7 +88,9 @@ static const struct watchdog_info imx2_wdt_info = {
 
 static inline void imx2_wdt_setup(void)
 {
-	u16 val = __raw_readw(imx2_wdt.base + IMX2_WDT_WCR);
+	u32 val;
+
+	regmap_read(imx2_wdt.regmap, IMX2_WDT_WCR, &val);
 
 	/* Suspend timer in low power mode, write once-only */
 	val |= IMX2_WDT_WCR_WDZST;
@@ -100,17 +103,17 @@ static inline void imx2_wdt_setup(void)
 	/* Set the watchdog's Time-Out value */
 	val |= WDOG_SEC_TO_COUNT(imx2_wdt.timeout);
 
-	__raw_writew(val, imx2_wdt.base + IMX2_WDT_WCR);
+	regmap_write(imx2_wdt.regmap, IMX2_WDT_WCR, val);
 
 	/* enable the watchdog */
 	val |= IMX2_WDT_WCR_WDE;
-	__raw_writew(val, imx2_wdt.base + IMX2_WDT_WCR);
+	regmap_write(imx2_wdt.regmap, IMX2_WDT_WCR, val);
 }
 
 static inline void imx2_wdt_ping(void)
 {
-	__raw_writew(IMX2_WDT_SEQ1, imx2_wdt.base + IMX2_WDT_WSR);
-	__raw_writew(IMX2_WDT_SEQ2, imx2_wdt.base + IMX2_WDT_WSR);
+	regmap_write(imx2_wdt.regmap, IMX2_WDT_WSR, IMX2_WDT_SEQ1);
+	regmap_write(imx2_wdt.regmap, IMX2_WDT_WSR, IMX2_WDT_SEQ2);
 }
 
 static void imx2_wdt_timer_ping(unsigned long arg)
@@ -143,12 +146,8 @@ static void imx2_wdt_stop(void)
 
 static void imx2_wdt_set_timeout(int new_timeout)
 {
-	u16 val = __raw_readw(imx2_wdt.base + IMX2_WDT_WCR);
-
-	/* set the new timeout value in the WSR */
-	val &= ~IMX2_WDT_WCR_WT;
-	val |= WDOG_SEC_TO_COUNT(new_timeout);
-	__raw_writew(val, imx2_wdt.base + IMX2_WDT_WCR);
+	regmap_update_bits(imx2_wdt.regmap, IMX2_WDT_WCR, IMX2_WDT_WCR_WT,
+			   WDOG_SEC_TO_COUNT(new_timeout));
 }
 
 static int imx2_wdt_open(struct inode *inode, struct file *file)
@@ -181,7 +180,7 @@ static long imx2_wdt_ioctl(struct file *file, unsigned int cmd,
 	void __user *argp = (void __user *)arg;
 	int __user *p = argp;
 	int new_value;
-	u16 val;
+	u32 val;
 
 	switch (cmd) {
 	case WDIOC_GETSUPPORT:
@@ -192,7 +191,7 @@ static long imx2_wdt_ioctl(struct file *file, unsigned int cmd,
 		return put_user(0, p);
 
 	case WDIOC_GETBOOTSTATUS:
-		val = __raw_readw(imx2_wdt.base + IMX2_WDT_WRSR);
+		regmap_read(imx2_wdt.regmap, IMX2_WDT_WRSR, &val);
 		new_value = val & IMX2_WDT_WRSR_TOUT ? WDIOF_CARDRESET : 0;
 		return put_user(new_value, p);
 
@@ -255,15 +254,30 @@ static struct miscdevice imx2_wdt_miscdev = {
 	.fops = &imx2_wdt_fops,
 };
 
+static struct regmap_config imx2_wdt_regmap_config = {
+	.reg_bits = 16,
+	.reg_stride = 2,
+	.val_bits = 16,
+	.max_register = 0x8,
+};
+
 static int __init imx2_wdt_probe(struct platform_device *pdev)
 {
-	int ret;
 	struct resource *res;
+	void __iomem *base;
+	int ret;
 
 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	imx2_wdt.base = devm_ioremap_resource(&pdev->dev, res);
-	if (IS_ERR(imx2_wdt.base))
-		return PTR_ERR(imx2_wdt.base);
+	base = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(base))
+		return PTR_ERR(base);
+
+	imx2_wdt.regmap = devm_regmap_init_mmio_clk(&pdev->dev, NULL, base,
+						    &imx2_wdt_regmap_config);
+	if (IS_ERR(imx2_wdt.regmap)) {
+		dev_err(&pdev->dev, "regmap init failed\n");
+		return PTR_ERR(imx2_wdt.regmap);
+	}
 
 	imx2_wdt.clk = devm_clk_get(&pdev->dev, NULL);
 	if (IS_ERR(imx2_wdt.clk)) {