mfd: max8998: Add support for Device Tree

This patch adds Device Tree support to max8998 driver.
Signed-off-by: Tomasz Figa <t.figa@samsung.com>
Acked-by: Mark Brown <broonie@linaro.org>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

Documentation/devicetree/bindings/mfd/max8998.txt

+* Maxim MAX8998, National/TI LP3974 multi-function device
+
+The Maxim MAX8998 is a multi-function device which includes voltage/current
+regulators, real time clock, battery charging controller and several
+other sub-blocks. It is interfaced using an I2C interface. Each sub-block
+is addressed by the host system using different i2c slave address.
+
+PMIC sub-block
+--------------
+
+The PMIC sub-block contains a number of voltage and current regulators,
+with controllable parameters and dynamic voltage scaling capability.
+In addition, it includes a real time clock and battery charging controller
+as well. It is accessible at I2C address 0x66.
+
+Required properties:
+- compatible: Should be one of the following:
+    - "maxim,max8998" for Maxim MAX8998
+    - "national,lp3974" or "ti,lp3974" for National/TI LP3974.
+- reg: Specifies the i2c slave address of the pmic block. It should be 0x66.
+
+Optional properties:
+- interrupt-parent: Specifies the phandle of the interrupt controller to which
+  the interrupts from MAX8998 are routed to.
+- interrupts: Interrupt specifiers for two interrupt sources.
+  - First interrupt specifier is for main interrupt.
+  - Second interrupt specifier is for power-on/-off interrupt.
+- max8998,pmic-buck1-dvs-gpios: GPIO specifiers for two host gpios used
+  for buck 1 dvs. The format of the gpio specifier depends on the gpio
+  controller.
+- max8998,pmic-buck2-dvs-gpio: GPIO specifier for host gpio used
+  for buck 2 dvs. The format of the gpio specifier depends on the gpio
+  controller.
+- max8998,pmic-buck1-default-dvs-idx: Default voltage setting selected from
+  the possible 4 options selectable by the dvs gpios. The value of this
+  property should be 0, 1, 2 or 3. If not specified or out of range,
+  a default value of 0 is taken.
+- max8998,pmic-buck2-default-dvs-idx: Default voltage setting selected from
+  the possible 2 options selectable by the dvs gpios. The value of this
+  property should be 0 or 1. If not specified or out of range, a default
+  value of 0 is taken.
+- max8998,pmic-buck-voltage-lock: If present, disallows changing of
+  preprogrammed buck dvfs voltages.
+
+Additional properties required if max8998,pmic-buck1-dvs-gpios is defined:
+- max8998,pmic-buck1-dvs-voltage: An array of 4 voltage values in microvolts
+  for buck1 regulator that can be selected using dvs gpio.
+
+Additional properties required if max8998,pmic-buck2-dvs-gpio is defined:
+- max8998,pmic-buck2-dvs-voltage: An array of 2 voltage values in microvolts
+  for buck2 regulator that can be selected using dvs gpio.
+
+Regulators: All the regulators of MAX8998 to be instantiated shall be
+listed in a child node named 'regulators'. Each regulator is represented
+by a child node of the 'regulators' node.
+
+	regulator-name {
+		/* standard regulator bindings here */
+	};
+
+Following regulators of the MAX8998 PMIC block are supported. Note that
+the 'n' in regulator name, as in LDOn or BUCKn, represents the LDO or BUCK
+number as described in MAX8998 datasheet.
+
+	- LDOn
+		  - valid values for n are 2 to 17
+		  - Example: LDO2, LDO10, LDO17
+	- BUCKn
+		  - valid values for n are 1 to 4.
+		  - Example: BUCK1, BUCK2, BUCK3, BUCK4
+
+	- ENVICHG: Battery Charging Current Monitor Output. This is a fixed
+		   voltage type regulator
+
+	- ESAFEOUT1: (ldo19)
+	- ESAFEOUT2: (ld020)
+
+Standard regulator bindings are used inside regulator subnodes. Check
+  Documentation/devicetree/bindings/regulator/regulator.txt
+for more details.
+
+Example:
+
+	pmic@66 {
+		compatible = "maxim,max8998-pmic";
+		reg = <0x66>;
+		interrupt-parent = <&wakeup_eint>;
+		interrupts = <4 0>, <3 0>;
+
+		/* Buck 1 DVS settings */
+		max8998,pmic-buck1-default-dvs-idx = <0>;
+		max8998,pmic-buck1-dvs-gpios = <&gpx0 0 1 0 0>, /* SET1 */
+					       <&gpx0 1 1 0 0>; /* SET2 */
+		max8998,pmic-buck1-dvs-voltage = <1350000>, <1300000>,
+						 <1000000>, <950000>;
+
+		/* Buck 2 DVS settings */
+		max8998,pmic-buck2-default-dvs-idx = <0>;
+		max8998,pmic-buck2-dvs-gpio = <&gpx0 0 3 0 0>; /* SET3 */
+		max8998,pmic-buck2-dvs-voltage = <1350000>, <1300000>;
+
+		/* Regulators to instantiate */
+		regulators {
+			ldo2_reg: LDO2 {
+				regulator-name = "VDD_ALIVE_1.1V";
+				regulator-min-microvolt = <1100000>;
+				regulator-max-microvolt = <1100000>;
+				regulator-always-on;
+			};
+
+			buck1_reg: BUCK1 {
+				regulator-name = "VDD_ARM_1.2V";
+				regulator-min-microvolt = <950000>;
+				regulator-max-microvolt = <1350000>;
+				regulator-always-on;
+				regulator-boot-on;
+			};
+		};
+	};

drivers/mfd/max8998.c

@@ -20,12 +20,15 @@
  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  */
 
+#include <linux/err.h>
 #include <linux/module.h>
 #include <linux/moduleparam.h>
 #include <linux/init.h>
 #include <linux/slab.h>
 #include <linux/i2c.h>
 #include <linux/interrupt.h>
+#include <linux/of.h>
+#include <linux/of_irq.h>
 #include <linux/pm_runtime.h>
 #include <linux/mutex.h>
 #include <linux/mfd/core.h>
@@ -128,6 +131,56 @@ int max8998_update_reg(struct i2c_client *i2c, u8 reg, u8 val, u8 mask)
 }
 EXPORT_SYMBOL(max8998_update_reg);
 
+#ifdef CONFIG_OF
+static struct of_device_id max8998_dt_match[] = {
+	{ .compatible = "maxim,max8998", .data = (void *)TYPE_MAX8998 },
+	{ .compatible = "national,lp3974", .data = (void *)TYPE_LP3974 },
+	{ .compatible = "ti,lp3974", .data = (void *)TYPE_LP3974 },
+	{},
+};
+MODULE_DEVICE_TABLE(of, max8998_dt_match);
+#endif
+
+/*
+ * Only the common platform data elements for max8998 are parsed here from the
+ * device tree. Other sub-modules of max8998 such as pmic, rtc and others have
+ * to parse their own platform data elements from device tree.
+ *
+ * The max8998 platform data structure is instantiated here and the drivers for
+ * the sub-modules need not instantiate another instance while parsing their
+ * platform data.
+ */
+static struct max8998_platform_data *max8998_i2c_parse_dt_pdata(
+							struct device *dev)
+{
+	struct max8998_platform_data *pd;
+
+	pd = devm_kzalloc(dev, sizeof(*pd), GFP_KERNEL);
+	if (!pd)
+		return ERR_PTR(-ENOMEM);
+
+	pd->ono = irq_of_parse_and_map(dev->of_node, 1);
+
+	/*
+	 * ToDo: the 'wakeup' member in the platform data is more of a linux
+	 * specfic information. Hence, there is no binding for that yet and
+	 * not parsed here.
+	 */
+	return pd;
+}
+
+static inline int max8998_i2c_get_driver_data(struct i2c_client *i2c,
+						const struct i2c_device_id *id)
+{
+	if (IS_ENABLED(CONFIG_OF) && i2c->dev.of_node) {
+		const struct of_device_id *match;
+		match = of_match_node(max8998_dt_match, i2c->dev.of_node);
+		return (int)match->data;
+	}
+
+	return (int)id->driver_data;
+}
+
 static int max8998_i2c_probe(struct i2c_client *i2c,
 			    const struct i2c_device_id *id)
 {
@@ -139,11 +192,20 @@ static int max8998_i2c_probe(struct i2c_client *i2c,
 	if (max8998 == NULL)
 		return -ENOMEM;
 
+	if (IS_ENABLED(CONFIG_OF) && i2c->dev.of_node) {
+		pdata = max8998_i2c_parse_dt_pdata(&i2c->dev);
+		if (IS_ERR(pdata)) {
+			ret = PTR_ERR(pdata);
+			goto err;
+		}
+	}
+
 	i2c_set_clientdata(i2c, max8998);
 	max8998->dev = &i2c->dev;
 	max8998->i2c = i2c;
 	max8998->irq = i2c->irq;
-	max8998->type = id->driver_data;
+	max8998->type = max8998_i2c_get_driver_data(i2c, id);
+	max8998->pdata = pdata;
 	if (pdata) {
 		max8998->ono = pdata->ono;
 		max8998->irq_base = pdata->irq_base;
@@ -158,7 +220,7 @@ static int max8998_i2c_probe(struct i2c_client *i2c,
 
 	pm_runtime_set_active(max8998->dev);
 
-	switch (id->driver_data) {
+	switch (max8998->type) {
 	case TYPE_LP3974:
 		ret = mfd_add_devices(max8998->dev, -1,
 				      lp3974_devs, ARRAY_SIZE(lp3974_devs),
@@ -314,6 +376,7 @@ static struct i2c_driver max8998_i2c_driver = {
 		   .name = "max8998",
 		   .owner = THIS_MODULE,
 		   .pm = &max8998_pm,
+		   .of_match_table = of_match_ptr(max8998_dt_match),
 	},
 	.probe = max8998_i2c_probe,
 	.remove = max8998_i2c_remove,

drivers/regulator/max8998.c

@@ -28,8 +28,11 @@
 #include <linux/slab.h>
 #include <linux/interrupt.h>
 #include <linux/mutex.h>
+#include <linux/of.h>
+#include <linux/of_gpio.h>
 #include <linux/platform_device.h>
 #include <linux/regulator/driver.h>
+#include <linux/regulator/of_regulator.h>
 #include <linux/mfd/max8998.h>
 #include <linux/mfd/max8998-private.h>
 
@@ -589,13 +592,13 @@ static struct regulator_desc regulators[] = {
 		.type		= REGULATOR_VOLTAGE,
 		.owner		= THIS_MODULE,
 	}, {
-		.name		= "EN32KHz AP",
+		.name		= "EN32KHz-AP",
 		.id		= MAX8998_EN32KHZ_AP,
 		.ops		= &max8998_others_ops,
 		.type		= REGULATOR_VOLTAGE,
 		.owner		= THIS_MODULE,
 	}, {
-		.name		= "EN32KHz CP",
+		.name		= "EN32KHz-CP",
 		.id		= MAX8998_EN32KHZ_CP,
 		.ops		= &max8998_others_ops,
 		.type		= REGULATOR_VOLTAGE,
@@ -621,10 +624,122 @@ static struct regulator_desc regulators[] = {
 	}
 };
 
+static int max8998_pmic_dt_parse_dvs_gpio(struct max8998_dev *iodev,
+			struct max8998_platform_data *pdata,
+			struct device_node *pmic_np)
+{
+	int gpio;
+
+	gpio = of_get_named_gpio(pmic_np, "max8998,pmic-buck1-dvs-gpios", 0);
+	if (!gpio_is_valid(gpio)) {
+		dev_err(iodev->dev, "invalid buck1 gpio[0]: %d\n", gpio);
+		return -EINVAL;
+	}
+	pdata->buck1_set1 = gpio;
+
+	gpio = of_get_named_gpio(pmic_np, "max8998,pmic-buck1-dvs-gpios", 1);
+	if (!gpio_is_valid(gpio)) {
+		dev_err(iodev->dev, "invalid buck1 gpio[1]: %d\n", gpio);
+		return -EINVAL;
+	}
+	pdata->buck1_set2 = gpio;
+
+	gpio = of_get_named_gpio(pmic_np, "max8998,pmic-buck2-dvs-gpio", 0);
+	if (!gpio_is_valid(gpio)) {
+		dev_err(iodev->dev, "invalid buck 2 gpio: %d\n", gpio);
+		return -EINVAL;
+	}
+	pdata->buck2_set3 = gpio;
+
+	return 0;
+}
+
+static int max8998_pmic_dt_parse_pdata(struct max8998_dev *iodev,
+					struct max8998_platform_data *pdata)
+{
+	struct device_node *pmic_np = iodev->dev->of_node;
+	struct device_node *regulators_np, *reg_np;
+	struct max8998_regulator_data *rdata;
+	unsigned int i;
+	int ret;
+
+	regulators_np = of_get_child_by_name(pmic_np, "regulators");
+	if (!regulators_np) {
+		dev_err(iodev->dev, "could not find regulators sub-node\n");
+		return -EINVAL;
+	}
+
+	/* count the number of regulators to be supported in pmic */
+	pdata->num_regulators = of_get_child_count(regulators_np);
+
+	rdata = devm_kzalloc(iodev->dev, sizeof(*rdata) *
+				pdata->num_regulators, GFP_KERNEL);
+	if (!rdata)
+		return -ENOMEM;
+
+	pdata->regulators = rdata;
+	for (i = 0; i < ARRAY_SIZE(regulators); ++i) {
+		reg_np = of_get_child_by_name(regulators_np,
+							regulators[i].name);
+		if (!reg_np)
+			continue;
+
+		rdata->id = regulators[i].id;
+		rdata->initdata = of_get_regulator_init_data(
+							iodev->dev, reg_np);
+		rdata->reg_node = reg_np;
+		++rdata;
+	}
+	pdata->num_regulators = rdata - pdata->regulators;
+
+	ret = max8998_pmic_dt_parse_dvs_gpio(iodev, pdata, pmic_np);
+	if (ret)
+		return -EINVAL;
+
+	if (of_find_property(pmic_np, "max8998,pmic-buck-voltage-lock", NULL))
+		pdata->buck_voltage_lock = true;
+
+	ret = of_property_read_u32(pmic_np,
+					"max8998,pmic-buck1-default-dvs-idx",
+					&pdata->buck1_default_idx);
+	if (!ret && pdata->buck1_default_idx >= 4) {
+		pdata->buck1_default_idx = 0;
+		dev_warn(iodev->dev, "invalid value for default dvs index, using 0 instead\n");
+	}
+
+	ret = of_property_read_u32(pmic_np,
+					"max8998,pmic-buck2-default-dvs-idx",
+					&pdata->buck2_default_idx);
+	if (!ret && pdata->buck2_default_idx >= 2) {
+		pdata->buck2_default_idx = 0;
+		dev_warn(iodev->dev, "invalid value for default dvs index, using 0 instead\n");
+	}
+
+	ret = of_property_read_u32_array(pmic_np,
+					"max8998,pmic-buck1-dvs-voltage",
+					pdata->buck1_voltage,
+					ARRAY_SIZE(pdata->buck1_voltage));
+	if (ret) {
+		dev_err(iodev->dev, "buck1 voltages not specified\n");
+		return -EINVAL;
+	}
+
+	ret = of_property_read_u32_array(pmic_np,
+					"max8998,pmic-buck2-dvs-voltage",
+					pdata->buck2_voltage,
+					ARRAY_SIZE(pdata->buck2_voltage));
+	if (ret) {
+		dev_err(iodev->dev, "buck2 voltages not specified\n");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
 static int max8998_pmic_probe(struct platform_device *pdev)
 {
 	struct max8998_dev *iodev = dev_get_drvdata(pdev->dev.parent);
-	struct max8998_platform_data *pdata = dev_get_platdata(iodev->dev);
+	struct max8998_platform_data *pdata = iodev->pdata;
 	struct regulator_config config = { };
 	struct regulator_dev **rdev;
 	struct max8998_data *max8998;
@@ -637,6 +752,12 @@ static int max8998_pmic_probe(struct platform_device *pdev)
 		return -ENODEV;
 	}
 
+	if (IS_ENABLED(CONFIG_OF) && iodev->dev->of_node) {
+		ret = max8998_pmic_dt_parse_pdata(iodev, pdata);
+		if (ret)
+			return ret;
+	}
+
 	max8998 = devm_kzalloc(&pdev->dev, sizeof(struct max8998_data),
 			       GFP_KERNEL);
 	if (!max8998)
@@ -750,13 +871,15 @@ static int max8998_pmic_probe(struct platform_device *pdev)
 		}
 
 		config.dev = max8998->dev;
+		config.of_node = pdata->regulators[i].reg_node;
 		config.init_data = pdata->regulators[i].initdata;
 		config.driver_data = max8998;
 
 		rdev[i] = regulator_register(&regulators[index], &config);
 		if (IS_ERR(rdev[i])) {
 			ret = PTR_ERR(rdev[i]);
-			dev_err(max8998->dev, "regulator init failed\n");
+			dev_err(max8998->dev, "regulator %s init failed (%d)\n",
+						regulators[index].name, ret);
 			rdev[i] = NULL;
 			goto err;
 		}

drivers/rtc/rtc-max8998.c

@@ -253,7 +253,7 @@ static const struct rtc_class_ops max8998_rtc_ops = {
 static int max8998_rtc_probe(struct platform_device *pdev)
 {
 	struct max8998_dev *max8998 = dev_get_drvdata(pdev->dev.parent);
-	struct max8998_platform_data *pdata = dev_get_platdata(max8998->dev);
+	struct max8998_platform_data *pdata = max8998->pdata;
 	struct max8998_rtc_info *info;
 	int ret;
 

include/linux/mfd/max8998-private.h

@@ -137,6 +137,7 @@ struct irq_domain;
 /**
  * struct max8998_dev - max8998 master device for sub-drivers
  * @dev: master device of the chip (can be used to access platform data)
+ * @pdata: platform data for the driver and subdrivers
  * @i2c: i2c client private data for regulator
  * @rtc: i2c client private data for rtc
  * @iolock: mutex for serializing io access
@@ -150,6 +151,7 @@ struct irq_domain;
  */
 struct max8998_dev {
 	struct device *dev;
+	struct max8998_platform_data *pdata;
 	struct i2c_client *i2c;
 	struct i2c_client *rtc;
 	struct mutex iolock;

include/linux/mfd/max8998.h

@@ -58,10 +58,12 @@ enum {
  * max8998_regulator_data - regulator data
  * @id: regulator id
  * @initdata: regulator init data (contraints, supplies, ...)
+ * @reg_node: DT node of regulator (unused on non-DT platforms)
  */
 struct max8998_regulator_data {
 	int				id;
 	struct regulator_init_data	*initdata;
+	struct device_node		*reg_node;
 };
 
 /**