[PATCH v4 2/2] mfd: rk808: Add restart functionality

[Daniel Schultz <d.schultz@phytec.de>]

When using Rockchip SoCs with rk805/808/818 PMICs, restarts are realized by
setting the reset registers in the "Clock and Reset Unit".

Now, the driver can trigger a restart in the PMIC. Like the
shutdown function, the restart is bound to an independent
"rockchip,system-reset-controller" devicetree property can easily
enabled by adding this.

Signed-off-by: Daniel Schultz <d.schultz@phytec.de>
---
Changes:
	v2: Re-submit with recipients from Rockchip.
	v3: - Added devicetree property to enable the PMIC reset seperate from 
	      "rockchip,system-power-controller".
	    - Dropped the first patch of this serie.
	v4: Splitted refactoring and the new reset feature.

 drivers/mfd/rk808.c       | 58 ++++++++++++++++++++++++++++++++++++++++++-----
 include/linux/mfd/rk808.h |  1 +
 2 files changed, 53 insertions(+), 6 deletions(-)

diff --git a/drivers/mfd/rk808.c b/drivers/mfd/rk808.c
index ae014ee..7dccf8f 100644
--- a/drivers/mfd/rk808.c
+++ b/drivers/mfd/rk808.c
@@ -27,6 +27,7 @@
 #include <linux/module.h>
 #include <linux/of_device.h>
 #include <linux/regmap.h>
+#include <linux/reboot.h>
 
 struct rk808_reg_data {
 	int addr;
@@ -393,16 +394,49 @@ static void rk805_device_shutdown(void)
 {
 	rk808_update_bits(RK805_DEV_CTRL_REG, DEV_OFF);
 }
+static int rk805_restart_notify(struct notifier_block *this,
+				   unsigned long mode, void *cmd)
+{
+	rk808_update_bits(RK805_DEV_CTRL_REG, DEV_OFF_RST);
+	return NOTIFY_DONE;
+}
 
 static void rk808_device_shutdown(void)
 {
 	rk808_update_bits(RK808_DEVCTRL_REG, DEV_OFF_RST);
 }
+static int rk808_restart_notify(struct notifier_block *this,
+				   unsigned long mode, void *cmd)
+{
+	rk808_update_bits(RK808_DEVCTRL_REG, DEV_OFF);
+	return NOTIFY_DONE;
+}
 
 static void rk818_device_shutdown(void)
 {
 	rk808_update_bits(RK818_DEVCTRL_REG, DEV_OFF);
 }
+static int rk818_restart_notify(struct notifier_block *this,
+				   unsigned long mode, void *cmd)
+{
+	rk808_update_bits(RK818_DEVCTRL_REG, DEV_OFF_RST);
+	return NOTIFY_DONE;
+}
+
+static struct notifier_block rk805_restart_handler = {
+	.notifier_call = rk805_restart_notify,
+	.priority = 196,
+};
+
+static struct notifier_block rk808_restart_handler = {
+	.notifier_call = rk808_restart_notify,
+	.priority = 196,
+};
+
+static struct notifier_block rk818_restart_handler = {
+	.notifier_call = rk818_restart_notify,
+	.priority = 196,
+};
 
 static const struct of_device_id rk808_of_match[] = {
 	{ .compatible = "rockchip,rk805" },
@@ -422,7 +456,7 @@ static int rk808_probe(struct i2c_client *client,
 	void (*pm_pwroff_fn)(void);
 	int nr_pre_init_regs;
 	int nr_cells;
-	int pm_off = 0, msb, lsb;
+	int pm_off = 0, pm_rst_off = 0, msb, lsb;
 	int ret;
 	int i;
 
@@ -457,6 +491,7 @@ static int rk808_probe(struct i2c_client *client,
 		cells = rk805s;
 		nr_cells = ARRAY_SIZE(rk805s);
 		pm_pwroff_fn = rk805_device_shutdown;
+		rk808->nb = &rk805_restart_handler;
 		break;
 	case RK808_ID:
 		rk808->regmap_cfg = &rk808_regmap_config;
@@ -466,6 +501,7 @@ static int rk808_probe(struct i2c_client *client,
 		cells = rk808s;
 		nr_cells = ARRAY_SIZE(rk808s);
 		pm_pwroff_fn = rk808_device_shutdown;
+		rk808->nb = &rk808_restart_handler;
 		break;
 	case RK818_ID:
 		rk808->regmap_cfg = &rk818_regmap_config;
@@ -475,6 +511,7 @@ static int rk808_probe(struct i2c_client *client,
 		cells = rk818s;
 		nr_cells = ARRAY_SIZE(rk818s);
 		pm_pwroff_fn = rk818_device_shutdown;
+		rk808->nb = &rk818_restart_handler;
 		break;
 	default:
 		dev_err(&client->dev, "Unsupported RK8XX ID %lu\n",
@@ -525,13 +562,20 @@ static int rk808_probe(struct i2c_client *client,
 		goto err_irq;
 	}
 
-	pm_off = of_property_read_bool(np,
-				"rockchip,system-power-controller");
-	if (pm_off && !pm_power_off) {
-		rk808_i2c_client = client;
+	rk808_i2c_client = client;
+
+	pm_off = of_property_read_bool(np, "rockchip,system-power-controller");
+	if (pm_off && !pm_power_off)
 		pm_power_off = pm_pwroff_fn;
-	}
 
+	pm_rst_off = of_property_read_bool(np,
+					"rockchip,system-reset-controller");
+	if (pm_rst_off && rk808->nb) {
+		ret = register_restart_handler(rk808->nb);
+		if (ret)
+			dev_err(&client->dev,
+				"cannot register restart handler, %d\n", ret);
+	}
 	return 0;
 
 err_irq:
@@ -545,6 +589,8 @@ static int rk808_remove(struct i2c_client *client)
 
 	regmap_del_irq_chip(client->irq, rk808->irq_data);
 	pm_power_off = NULL;
+	if (rk808->nb)
+		unregister_restart_handler(rk808->nb);
 
 	return 0;
 }
diff --git a/include/linux/mfd/rk808.h b/include/linux/mfd/rk808.h
index 338e0f6..9c26ca2 100644
--- a/include/linux/mfd/rk808.h
+++ b/include/linux/mfd/rk808.h
@@ -453,5 +453,6 @@ struct rk808 {
 	long				variant;
 	const struct regmap_config	*regmap_cfg;
 	const struct regmap_irq_chip	*regmap_irq_chip;
+	struct notifier_block		*nb;
 };
 #endif /* __LINUX_REGULATOR_RK808_H */
-- 
2.7.4