MIPS: AR7: register watchdog device only if enabled in hw configuration

This patch checks if the watchdog enable bit is set in the DCL register
meaning that the hardware watchdog actually works and if so, register the
ar7_wdt platform_device.
Signed-off-by: Florian Fainelli <florian@openwrt.org>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/ar7/platform.c

@@ -503,6 +503,7 @@ static int __init ar7_register_devices(void)
 {
 	u16 chip_id;
 	int res;
+	u32 *bootcr, val;
 #ifdef CONFIG_SERIAL_8250
 	static struct uart_port uart_port[2];
 
@@ -595,7 +596,13 @@ static int __init ar7_register_devices(void)
 
 	ar7_wdt_res.end = ar7_wdt_res.start + 0x20;
 
-	res = platform_device_register(&ar7_wdt);
+	bootcr = (u32 *)ioremap_nocache(AR7_REGS_DCL, 4);
+	val = *bootcr;
+	iounmap(bootcr);
+
+	/* Register watchdog only if enabled in hardware */
+	if (val & AR7_WDT_HW_ENA)
+		res = platform_device_register(&ar7_wdt);
 
 	return res;
 }

arch/mips/include/asm/mach-ar7/ar7.h

@@ -78,6 +78,9 @@
 #define AR7_REF_CLOCK	25000000
 #define AR7_XTAL_CLOCK	24000000
 
+/* DCL */
+#define AR7_WDT_HW_ENA	0x10
+
 struct plat_cpmac_data {
 	int reset_bit;
 	int power_bit;