Revert "Revert "mfd: rk808: power off system in syscore shutdown""

This reverts commit 58c1b9e.

Author: jamess-huang

drivers/mfd/rk808.c

@@ -16,6 +16,7 @@
  * more details.
  */
 
+#include <linux/delay.h>
 #include <linux/i2c.h>
 #include <linux/interrupt.h>
 #include <linux/kernel.h>
@@ -24,6 +25,7 @@
 #include <linux/module.h>
 #include <linux/of_device.h>
 #include <linux/regmap.h>
+#include <linux/syscore_ops.h>
 
 struct rk808_reg_data {
 	int addr;
@@ -812,7 +814,7 @@ static void rk808_device_shutdown_prepare(void)
 	}
 }
 
-static void rk808_device_shutdown(void)
+static void rk808_syscore_shutdown(void)
 {
 	int ret;
 	struct rk808 *rk808 = i2c_get_clientdata(rk808_i2c_client);
@@ -830,13 +832,35 @@ static void rk808_device_shutdown(void)
 	regmap_update_bits(rk808->regmap,
 			   RK808_RTC_INT_REG,
 			   (0x3 << 2), (0x0 << 2));
-	if (pm_shutdown) {
-		ret = pm_shutdown(rk808->regmap);
-		if (ret)
-			dev_err(&rk808_i2c_client->dev, "power off error!\n");
+	/*
+	 * For PMIC that power off supplies by write register via i2c bus,
+	 * it's better to do power off at syscore shutdown here.
+	 *
+	 * Because when run to kernel's "pm_power_off" call, i2c may has
+	 * been stopped or PMIC may not be able to get i2c transfer while
+	 * there are too many devices are competiting.
+	 */
+	if (system_state == SYSTEM_POWER_OFF) {
+		/* power off supplies ! */
+		if (pm_shutdown) {
+			dev_info(&rk808_i2c_client->dev, "System power off\n");
+			ret = pm_shutdown(rk808->regmap);
+			if (ret)
+				dev_err(&rk808_i2c_client->dev,
+					"System power off error!\n");
+			mdelay(10);
+			dev_info(&rk808_i2c_client->dev,
+				 "Cpu should never reach here, stop!\n");
+			while (1)
+				;
+		}
 	}
 }
 
+static struct syscore_ops rk808_syscore_ops = {
+	.shutdown = rk808_syscore_shutdown,
+};
+
 static ssize_t rk8xx_dbg_store(struct device *dev,
 			       struct device_attribute *attr,
 			       const char *buf, size_t count)
@@ -1104,7 +1128,7 @@ static int rk808_probe(struct i2c_client *client,
 		}
 		if (pm_shutdown_fn) {
 			pm_shutdown = pm_shutdown_fn;
-			pm_power_off = rk808_device_shutdown;
+			register_syscore_ops(&rk808_syscore_ops);
 		}
 	}
 
@@ -1170,10 +1194,11 @@ static int rk808_remove(struct i2c_client *client)
 
 	regmap_del_irq_chip(client->irq, rk808->irq_data);
 	mfd_remove_devices(&client->dev);
-	if (pm_power_off == rk808_device_shutdown)
-		pm_power_off = NULL;
+
 	if (pm_power_off_prepare == rk808_device_shutdown_prepare)
 		pm_power_off_prepare = NULL;
+	if (pm_shutdown)
+		unregister_syscore_ops(&rk808_syscore_ops);
 
 	return 0;
 }