mfd: dt: tps6586x: Add power off control

Add DT property "ti,system-power-controller" telling whether or not this
pmic is in charge of controlling the system power, so the power off
routine can be hooked up to system call "pm_power_off".

Based on the work by:
Dan Willemsen <dwillemsen@nvidia.com>
Signed-off-by: Bill Huang <bilhuang@nvidia.com>
Tested-by: Stephen Warren <swarren@wwwdotorg.org>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

Documentation/devicetree/bindings/regulator/tps6586x.txt

@@ -18,6 +18,10 @@ Required properties:
 - vinldo678-supply: The input supply for the LDO6, LDO7 and LDO8
 - vinldo9-supply: The input supply for the LDO9
 
+Optional properties:
+- ti,system-power-controller: Telling whether or not this pmic is controlling
+  the system power.
+
 Each regulator is defined using the standard binding for regulators.
 
 Example:
@@ -30,6 +34,8 @@ Example:
 		#gpio-cells = <2>;
 		gpio-controller;
 
+		ti,system-power-controller;
+
 		sm0-supply = <&some_reg>;
 		sm1-supply = <&some_reg>;
 		sm2-supply = <&some_reg>;

drivers/mfd/tps6586x.c

@@ -29,6 +29,10 @@
 #include <linux/mfd/core.h>
 #include <linux/mfd/tps6586x.h>
 
+#define TPS6586X_SUPPLYENE	0x14
+#define EXITSLREQ_BIT		BIT(1)
+#define SLEEP_MODE_BIT		BIT(3)
+
 /* interrupt control registers */
 #define TPS6586X_INT_ACK1	0xb5
 #define TPS6586X_INT_ACK2	0xb6
@@ -409,6 +413,7 @@ static struct tps6586x_platform_data *tps6586x_parse_dt(struct i2c_client *clien
 	pdata->subdevs = devs;
 	pdata->gpio_base = -1;
 	pdata->irq_base = -1;
+	pdata->pm_off = of_property_read_bool(np, "ti,system-power-controller");
 
 	return pdata;
 }
@@ -441,6 +446,15 @@ static const struct regmap_config tps6586x_regmap_config = {
 	.cache_type = REGCACHE_RBTREE,
 };
 
+static struct device *tps6586x_dev;
+static void tps6586x_power_off(void)
+{
+	if (tps6586x_clr_bits(tps6586x_dev, TPS6586X_SUPPLYENE, EXITSLREQ_BIT))
+		return;
+
+	tps6586x_set_bits(tps6586x_dev, TPS6586X_SUPPLYENE, SLEEP_MODE_BIT);
+}
+
 static int __devinit tps6586x_i2c_probe(struct i2c_client *client,
 					const struct i2c_device_id *id)
 {
@@ -506,6 +520,11 @@ static int __devinit tps6586x_i2c_probe(struct i2c_client *client,
 		goto err_add_devs;
 	}
 
+	if (pdata->pm_off && !pm_power_off) {
+		tps6586x_dev = &client->dev;
+		pm_power_off = tps6586x_power_off;
+	}
+
 	return 0;
 
 err_add_devs:

include/linux/mfd/tps6586x.h

@@ -77,6 +77,7 @@ struct tps6586x_platform_data {
 
 	int gpio_base;
 	int irq_base;
+	bool pm_off;
 };
 
 /*