mfd: rk808: Add reboot support to rk808.c

This adds reboot support to the rk808 pmic driver and enables it for
the rk809 and rk817 devices.
This only enables if the rockchip,system-power-controller flag is set.
Signed-off-by: Peter Geis <pgwipeout@gmail.com>
Signed-off-by: Frank Wunderlich <frank-w@public-files.de>
Reviewed-by: Dmitry Osipenko <digetx@gmail.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Link: https://lore.kernel.org/r/20220208194023.929720-1-pgwipeout@gmail.com

drivers/mfd/rk808.c

@@ -19,6 +19,7 @@
 #include <linux/module.h>
 #include <linux/of_device.h>
 #include <linux/regmap.h>
+#include <linux/reboot.h>
 
 struct rk808_reg_data {
 	int addr;
@@ -543,6 +544,7 @@ static void rk808_pm_power_off(void)
 		reg = RK808_DEVCTRL_REG,
 		bit = DEV_OFF_RST;
 		break;
+	case RK809_ID:
 	case RK817_ID:
 		reg = RK817_SYS_CFG(3);
 		bit = DEV_OFF;
@@ -559,6 +561,34 @@ static void rk808_pm_power_off(void)
 		dev_err(&rk808_i2c_client->dev, "Failed to shutdown device!\n");
 }
 
+static int rk808_restart_notify(struct notifier_block *this, unsigned long mode, void *cmd)
+{
+	struct rk808 *rk808 = i2c_get_clientdata(rk808_i2c_client);
+	unsigned int reg, bit;
+	int ret;
+
+	switch (rk808->variant) {
+	case RK809_ID:
+	case RK817_ID:
+		reg = RK817_SYS_CFG(3);
+		bit = DEV_RST;
+		break;
+
+	default:
+		return NOTIFY_DONE;
+	}
+	ret = regmap_update_bits(rk808->regmap, reg, bit, bit);
+	if (ret)
+		dev_err(&rk808_i2c_client->dev, "Failed to restart device!\n");
+
+	return NOTIFY_DONE;
+}
+
+static struct notifier_block rk808_restart_handler = {
+	.notifier_call = rk808_restart_notify,
+	.priority = 192,
+};
+
 static void rk8xx_shutdown(struct i2c_client *client)
 {
 	struct rk808 *rk808 = i2c_get_clientdata(client);
@@ -727,6 +757,18 @@ static int rk808_probe(struct i2c_client *client,
 	if (of_property_read_bool(np, "rockchip,system-power-controller")) {
 		rk808_i2c_client = client;
 		pm_power_off = rk808_pm_power_off;
+
+		switch (rk808->variant) {
+		case RK809_ID:
+		case RK817_ID:
+			ret = register_restart_handler(&rk808_restart_handler);
+			if (ret)
+				dev_warn(&client->dev, "failed to register rst handler, %d\n", ret);
+			break;
+		default:
+			dev_dbg(&client->dev, "pmic controlled board reset not supported\n");
+			break;
+		}
 	}
 
 	return 0;
@@ -749,6 +791,8 @@ static int rk808_remove(struct i2c_client *client)
 	if (pm_power_off == rk808_pm_power_off)
 		pm_power_off = NULL;
 
+	unregister_restart_handler(&rk808_restart_handler);
+
 	return 0;
 }
 

include/linux/mfd/rk808.h

@@ -373,6 +373,7 @@ enum rk805_reg {
 #define SWITCH2_EN	BIT(6)
 #define SWITCH1_EN	BIT(5)
 #define DEV_OFF_RST	BIT(3)
+#define DEV_RST		BIT(2)
 #define DEV_OFF		BIT(0)
 #define RTC_STOP	BIT(0)