power/reset: keystone: Register with kernel restart handler

Register with kernel restart handler instead of setting arm_pm_restart directly.

Move notifier registration to the end of the probe function to avoid having to
implement error handling.

Cc: Ivan Khoronzhuk <ivan.khoronzhuk@ti.com>
Cc: Santosh Shilimkar <santosh.shilimkar@ti.com>
Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Tested-by: Ivan Khoronzhuk <ivan.khoronzhuk@ti.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

drivers/power/reset/keystone-reset.c

@@ -12,9 +12,9 @@
 
 #include <linux/io.h>
 #include <linux/module.h>
+#include <linux/notifier.h>
 #include <linux/reboot.h>
 #include <linux/regmap.h>
-#include <asm/system_misc.h>
 #include <linux/mfd/syscon.h>
 #include <linux/of_platform.h>
 
@@ -52,7 +52,8 @@ static inline int rsctrl_enable_rspll_write(void)
 				  RSCTRL_KEY_MASK, RSCTRL_KEY);
 }
 
-static void rsctrl_restart(enum reboot_mode mode, const char *cmd)
+static int rsctrl_restart_handler(struct notifier_block *this,
+				  unsigned long mode, void *cmd)
 {
 	/* enable write access to RSTCTRL */
 	rsctrl_enable_rspll_write();
@@ -60,8 +61,15 @@ static void rsctrl_restart(enum reboot_mode mode, const char *cmd)
 	/* reset the SOC */
 	regmap_update_bits(pllctrl_regs, rspll_offset + RSCTRL_RG,
 			   RSCTRL_RESET_MASK, 0);
+
+	return NOTIFY_DONE;
 }
 
+static struct notifier_block rsctrl_restart_nb = {
+	.notifier_call = rsctrl_restart_handler,
+	.priority = 128,
+};
+
 static struct of_device_id rsctrl_of_match[] = {
 	{.compatible = "ti,keystone-reset", },
 	{},
@@ -114,8 +122,6 @@ static int rsctrl_probe(struct platform_device *pdev)
 	if (ret)
 		return ret;
 
-	arm_pm_restart = rsctrl_restart;
-
 	/* disable a reset isolation for all module clocks */
 	ret = regmap_write(pllctrl_regs, rspll_offset + RSISO_RG, 0);
 	if (ret)
@@ -147,7 +153,11 @@ static int rsctrl_probe(struct platform_device *pdev)
 			return ret;
 	}
 
-	return 0;
+	ret = register_restart_handler(&rsctrl_restart_nb);
+	if (ret)
+		dev_err(dev, "cannot register restart handler (err=%d)\n", ret);
+
+	return ret;
 }
 
 static struct platform_driver rsctrl_driver = {