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 <[e-mail]>

Signed-off-by: Bill Huang <[e-mail]>
Tested-by: Stephen Warren <[e-mail]>
Signed-off-by: Samuel Ortiz <[e-mail]>

Documentation/devicetree/bindings/regulator/tps6586x.txt

···
 - 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:
···
 
 		#gpio-cells = <2>;
 		gpio-controller;
+
+		ti,system-power-controller;
 
 		sm0-supply = <&some_reg>;
 		sm1-supply = <&some_reg>;

drivers/mfd/tps6586x.c

···
 #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
···
 	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;
 }
···
 	.volatile_reg = is_volatile_reg,
 	.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)
···
 	if (ret) {
 		dev_err(&client->dev, "add devices failed: %d\n", ret);
 		goto err_add_devs;
+	}
+
+	if (pdata->pm_off && !pm_power_off) {
+		tps6586x_dev = &client->dev;
+		pm_power_off = tps6586x_power_off;
 	}
 
 	return 0;

include/linux/mfd/tps6586x.h

···
 
 	int gpio_base;
 	int irq_base;
+	bool pm_off;
 };
 
 /*