regulator: max8952: Add Device Tree support

This patch adds Device Tree support to max8952 regulator driver.
Signed-off-by: Tomasz Figa <t.figa@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

Documentation/devicetree/bindings/regulator/max8952.txt

+Maxim MAX8952 voltage regulator
+
+Required properties:
+- compatible: must be equal to "maxim,max8952"
+- reg: I2C slave address, usually 0x60
+- max8952,dvs-mode-microvolt: array of 4 integer values defining DVS voltages
+  in microvolts. All values must be from range <770000, 1400000>
+- any required generic properties defined in regulator.txt
+
+Optional properties:
+- max8952,vid-gpios: array of two GPIO pins used for DVS voltage selection
+- max8952,en-gpio: GPIO used to control enable status of regulator
+- max8952,default-mode: index of default DVS voltage, from <0, 3> range
+- max8952,sync-freq: sync frequency, must be one of following values:
+    - 0: 26 MHz
+    - 1: 13 MHz
+    - 2: 19.2 MHz
+  Defaults to 26 MHz if not specified.
+- max8952,ramp-speed: voltage ramp speed, must be one of following values:
+    - 0: 32mV/us
+    - 1: 16mV/us
+    - 2: 8mV/us
+    - 3: 4mV/us
+    - 4: 2mV/us
+    - 5: 1mV/us
+    - 6: 0.5mV/us
+    - 7: 0.25mV/us
+  Defaults to 32mV/us if not specified.
+- any available generic properties defined in regulator.txt
+
+Example:
+
+	vdd_arm_reg: pmic@60 {
+		compatible = "maxim,max8952";
+		reg = <0x60>;
+
+		/* max8952-specific properties */
+		max8952,vid-gpios = <&gpx0 3 0>, <&gpx0 4 0>;
+		max8952,en-gpio = <&gpx0 1 0>;
+		max8952,default-mode = <0>;
+		max8952,dvs-mode-microvolt = <1250000>, <1200000>,
+						<1050000>, <950000>;
+		max8952,sync-freq = <0>;
+		max8952,ramp-speed = <0>;
+
+		/* generic regulator properties */
+		regulator-name = "vdd_arm";
+		regulator-min-microvolt = <770000>;
+		regulator-max-microvolt = <1400000>;
+		regulator-always-on;
+		regulator-boot-on;
+	};

drivers/regulator/max8952.c

@@ -28,6 +28,9 @@
 #include <linux/regulator/max8952.h>
 #include <linux/gpio.h>
 #include <linux/io.h>
+#include <linux/of.h>
+#include <linux/of_gpio.h>
+#include <linux/regulator/of_regulator.h>
 #include <linux/slab.h>
 
 /* Registers */
@@ -126,6 +129,69 @@ static const struct regulator_desc regulator = {
 	.owner		= THIS_MODULE,
 };
 
+#ifdef CONFIG_OF
+static struct of_device_id max8952_dt_match[] = {
+	{ .compatible = "maxim,max8952" },
+	{},
+};
+MODULE_DEVICE_TABLE(of, max8952_dt_match);
+
+static struct max8952_platform_data *max8952_parse_dt(struct device *dev)
+{
+	struct max8952_platform_data *pd;
+	struct device_node *np = dev->of_node;
+	int ret;
+	int i;
+
+	pd = devm_kzalloc(dev, sizeof(*pd), GFP_KERNEL);
+	if (!pd) {
+		dev_err(dev, "Failed to allocate platform data\n");
+		return NULL;
+	}
+
+	pd->gpio_vid0 = of_get_named_gpio(np, "max8952,vid-gpios", 0);
+	pd->gpio_vid1 = of_get_named_gpio(np, "max8952,vid-gpios", 1);
+	pd->gpio_en = of_get_named_gpio(np, "max8952,en-gpio", 0);
+
+	if (of_property_read_u32(np, "max8952,default-mode", &pd->default_mode))
+		dev_warn(dev, "Default mode not specified, assuming 0\n");
+
+	ret = of_property_read_u32_array(np, "max8952,dvs-mode-microvolt",
+					pd->dvs_mode, ARRAY_SIZE(pd->dvs_mode));
+	if (ret) {
+		dev_err(dev, "max8952,dvs-mode-microvolt property not specified");
+		return NULL;
+	}
+
+	for (i = 0; i < ARRAY_SIZE(pd->dvs_mode); ++i) {
+		if (pd->dvs_mode[i] < 770000 || pd->dvs_mode[i] > 1400000) {
+			dev_err(dev, "DVS voltage %d out of range\n", i);
+			return NULL;
+		}
+		pd->dvs_mode[i] = (pd->dvs_mode[i] - 770000) / 10000;
+	}
+
+	if (of_property_read_u32(np, "max8952,sync-freq", &pd->sync_freq))
+		dev_warn(dev, "max8952,sync-freq property not specified, defaulting to 26MHz\n");
+
+	if (of_property_read_u32(np, "max8952,ramp-speed", &pd->ramp_speed))
+		dev_warn(dev, "max8952,ramp-speed property not specified, defaulting to 32mV/us\n");
+
+	pd->reg_data = of_get_regulator_init_data(dev, np);
+	if (!pd->reg_data) {
+		dev_err(dev, "Failed to parse regulator init data\n");
+		return NULL;
+	}
+
+	return pd;
+}
+#else
+static struct max8952_platform_data *max8952_parse_dt(struct device *dev)
+{
+	return NULL;
+}
+#endif
+
 static int max8952_pmic_probe(struct i2c_client *client,
 		const struct i2c_device_id *i2c_id)
 {
@@ -136,6 +202,9 @@ static int max8952_pmic_probe(struct i2c_client *client,
 
 	int ret = 0, err = 0;
 
+	if (client->dev.of_node)
+		pdata = max8952_parse_dt(&client->dev);
+
 	if (!pdata) {
 		dev_err(&client->dev, "Require the platform data\n");
 		return -EINVAL;
@@ -271,6 +340,7 @@ static struct i2c_driver max8952_pmic_driver = {
 	.remove		= max8952_pmic_remove,
 	.driver		= {
 		.name	= "max8952",
+		.of_match_table = of_match_ptr(max8952_dt_match),
 	},
 	.id_table	= max8952_ids,
 };

include/linux/regulator/max8952.h

@@ -122,11 +122,11 @@ struct max8952_platform_data {
 	int gpio_vid1;
 	int gpio_en;
 
-	u8 default_mode;
-	u8 dvs_mode[MAX8952_NUM_DVS_MODE]; /* MAX8952_DVS_MODEx_XXXXmV */
+	u32 default_mode;
+	u32 dvs_mode[MAX8952_NUM_DVS_MODE]; /* MAX8952_DVS_MODEx_XXXXmV */
 
-	u8 sync_freq;
-	u8 ramp_speed;
+	u32 sync_freq;
+	u32 ramp_speed;
 
 	struct regulator_init_data *reg_data;
 };