watchdog: at91rm9200: use the system timer syscon

Use a syscon regmap to access the system timer registers.

Also, rename the driver atmel_st_watchdog to stop conflicting with
at91sam9_wdt.c

Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>

drivers/watchdog/Kconfig

@@ -154,7 +154,7 @@ config ARM_SP805_WATCHDOG
 
 config AT91RM9200_WATCHDOG
 	tristate "AT91RM9200 watchdog"
-	depends on SOC_AT91RM9200
+	depends on SOC_AT91RM9200 && MFD_SYSCON
 	help
 	  Watchdog timer embedded into AT91RM9200 chips. This will reboot your
 	  system when the timeout is reached.

drivers/watchdog/at91rm9200_wdt.c

@@ -17,22 +17,25 @@
 #include <linux/init.h>
 #include <linux/io.h>
 #include <linux/kernel.h>
+#include <linux/mfd/syscon.h>
+#include <linux/mfd/syscon/atmel-st.h>
 #include <linux/miscdevice.h>
 #include <linux/module.h>
 #include <linux/moduleparam.h>
 #include <linux/platform_device.h>
+#include <linux/regmap.h>
 #include <linux/types.h>
 #include <linux/watchdog.h>
 #include <linux/uaccess.h>
 #include <linux/of.h>
 #include <linux/of_device.h>
-#include <mach/at91_st.h>
 
 #define WDT_DEFAULT_TIME	5	/* seconds */
 #define WDT_MAX_TIME		256	/* seconds */
 
 static int wdt_time = WDT_DEFAULT_TIME;
 static bool nowayout = WATCHDOG_NOWAYOUT;
+static struct regmap *regmap_st;
 
 module_param(wdt_time, int, 0);
 MODULE_PARM_DESC(wdt_time, "Watchdog time in seconds. (default="
@@ -55,7 +58,7 @@ static unsigned long at91wdt_busy;
  */
 static inline void at91_wdt_stop(void)
 {
-	at91_st_write(AT91_ST_WDMR, AT91_ST_EXTEN);
+	regmap_write(regmap_st, AT91_ST_WDMR, AT91_ST_EXTEN);
 }
 
 /*
@@ -63,9 +66,9 @@ static inline void at91_wdt_stop(void)
  */
 static inline void at91_wdt_start(void)
 {
-	at91_st_write(AT91_ST_WDMR, AT91_ST_EXTEN | AT91_ST_RSTEN |
+	regmap_write(regmap_st, AT91_ST_WDMR, AT91_ST_EXTEN | AT91_ST_RSTEN |
 				(((65536 * wdt_time) >> 8) & AT91_ST_WDV));
-	at91_st_write(AT91_ST_CR, AT91_ST_WDRST);
+	regmap_write(regmap_st, AT91_ST_CR, AT91_ST_WDRST);
 }
 
 /*
@@ -73,7 +76,7 @@ static inline void at91_wdt_start(void)
  */
 static inline void at91_wdt_reload(void)
 {
-	at91_st_write(AT91_ST_CR, AT91_ST_WDRST);
+	regmap_write(regmap_st, AT91_ST_CR, AT91_ST_WDRST);
 }
 
 /* ......................................................................... */
@@ -203,12 +206,24 @@ static struct miscdevice at91wdt_miscdev = {
 
 static int at91wdt_probe(struct platform_device *pdev)
 {
+	struct device *dev = &pdev->dev;
+	struct device *parent;
 	int res;
 
 	if (at91wdt_miscdev.parent)
 		return -EBUSY;
 	at91wdt_miscdev.parent = &pdev->dev;
 
+	parent = dev->parent;
+	if (!parent) {
+		dev_err(dev, "no parent\n");
+		return -ENODEV;
+	}
+
+	regmap_st = syscon_node_to_regmap(parent->of_node);
+	if (!regmap_st)
+		return -ENODEV;
+
 	res = misc_register(&at91wdt_miscdev);
 	if (res)
 		return res;
@@ -267,7 +282,7 @@ static struct platform_driver at91wdt_driver = {
 	.suspend	= at91wdt_suspend,
 	.resume		= at91wdt_resume,
 	.driver		= {
-		.name	= "at91_wdt",
+		.name	= "atmel_st_watchdog",
 		.of_match_table = at91_wdt_dt_ids,
 	},
 };
@@ -296,4 +311,4 @@ module_exit(at91_wdt_exit);
 MODULE_AUTHOR("Andrew Victor");
 MODULE_DESCRIPTION("Watchdog driver for Atmel AT91RM9200");
 MODULE_LICENSE("GPL");
-MODULE_ALIAS("platform:at91_wdt");
+MODULE_ALIAS("platform:atmel_st_watchdog");