hwmon: (pmbus) Add regulator support

Add support for simple on/off control of each channel.

To add regulator support, the pmbus part driver needs to add
regulator_desc information and number of regulators to its
pmbus_driver_info struct.

regulator_desc can be declared using default macro for a
regulator (PMBUS_REGULATOR) that is in pmbus.h

The regulator_init_data can be initialized from either
platform data or the device tree.
Signed-off-by: Alan Tull <atull@opensource.altera.com>
Reviewed-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

drivers/hwmon/pmbus/pmbus.h

@@ -19,6 +19,8 @@
  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  */
 
+#include <linux/regulator/driver.h>
+
 #ifndef PMBUS_H
 #define PMBUS_H
 
@@ -185,6 +187,11 @@
 #define PMBUS_VIRT_VMON_OV_FAULT_LIMIT	(PMBUS_VIRT_BASE + 34)
 #define PMBUS_VIRT_STATUS_VMON		(PMBUS_VIRT_BASE + 35)
 
+/*
+ * OPERATION
+ */
+#define PB_OPERATION_CONTROL_ON		(1<<7)
+
 /*
  * CAPABILITY
  */
@@ -365,8 +372,27 @@ struct pmbus_driver_info {
 	 */
 	int (*identify)(struct i2c_client *client,
 			struct pmbus_driver_info *info);
+
+	/* Regulator functionality, if supported by this chip driver. */
+	int num_regulators;
+	const struct regulator_desc *reg_desc;
 };
 
+/* Regulator ops */
+
+extern struct regulator_ops pmbus_regulator_ops;
+
+/* Macro for filling in array of struct regulator_desc */
+#define PMBUS_REGULATOR(_name, _id)				\
+	[_id] = {						\
+		.name = (_name # _id),				\
+		.id = (_id),					\
+		.of_match = of_match_ptr(_name # _id),		\
+		.regulators_node = of_match_ptr("regulators"),	\
+		.ops = &pmbus_regulator_ops,			\
+		.owner = THIS_MODULE,				\
+	}
+
 /* Function declarations */
 
 void pmbus_clear_cache(struct i2c_client *client);

drivers/hwmon/pmbus/pmbus_core.c

@@ -29,6 +29,8 @@
 #include <linux/hwmon-sysfs.h>
 #include <linux/jiffies.h>
 #include <linux/i2c/pmbus.h>
+#include <linux/regulator/driver.h>
+#include <linux/regulator/machine.h>
 #include "pmbus.h"
 
 /*
@@ -1758,6 +1760,84 @@ static int pmbus_init_common(struct i2c_client *client, struct pmbus_data *data,
 	return 0;
 }
 
+#if IS_ENABLED(CONFIG_REGULATOR)
+static int pmbus_regulator_is_enabled(struct regulator_dev *rdev)
+{
+	struct device *dev = rdev_get_dev(rdev);
+	struct i2c_client *client = to_i2c_client(dev->parent);
+	u8 page = rdev_get_id(rdev);
+	int ret;
+
+	ret = pmbus_read_byte_data(client, page, PMBUS_OPERATION);
+	if (ret < 0)
+		return ret;
+
+	return !!(ret & PB_OPERATION_CONTROL_ON);
+}
+
+static int _pmbus_regulator_on_off(struct regulator_dev *rdev, bool enable)
+{
+	struct device *dev = rdev_get_dev(rdev);
+	struct i2c_client *client = to_i2c_client(dev->parent);
+	u8 page = rdev_get_id(rdev);
+
+	return pmbus_update_byte_data(client, page, PMBUS_OPERATION,
+				      PB_OPERATION_CONTROL_ON,
+				      enable ? PB_OPERATION_CONTROL_ON : 0);
+}
+
+static int pmbus_regulator_enable(struct regulator_dev *rdev)
+{
+	return _pmbus_regulator_on_off(rdev, 1);
+}
+
+static int pmbus_regulator_disable(struct regulator_dev *rdev)
+{
+	return _pmbus_regulator_on_off(rdev, 0);
+}
+
+struct regulator_ops pmbus_regulator_ops = {
+	.enable = pmbus_regulator_enable,
+	.disable = pmbus_regulator_disable,
+	.is_enabled = pmbus_regulator_is_enabled,
+};
+EXPORT_SYMBOL_GPL(pmbus_regulator_ops);
+
+static int pmbus_regulator_register(struct pmbus_data *data)
+{
+	struct device *dev = data->dev;
+	const struct pmbus_driver_info *info = data->info;
+	const struct pmbus_platform_data *pdata = dev_get_platdata(dev);
+	struct regulator_dev *rdev;
+	int i;
+
+	for (i = 0; i < info->num_regulators; i++) {
+		struct regulator_config config = { };
+
+		config.dev = dev;
+		config.driver_data = data;
+
+		if (pdata && pdata->reg_init_data)
+			config.init_data = &pdata->reg_init_data[i];
+
+		rdev = devm_regulator_register(dev, &info->reg_desc[i],
+					       &config);
+		if (IS_ERR(rdev)) {
+			dev_err(dev, "Failed to register %s regulator\n",
+				info->reg_desc[i].name);
+			return PTR_ERR(rdev);
+		}
+	}
+
+	return 0;
+}
+#else
+static int pmbus_regulator_register(struct pmbus_data *data)
+{
+	return 0;
+}
+#endif
+
 int pmbus_do_probe(struct i2c_client *client, const struct i2c_device_id *id,
 		   struct pmbus_driver_info *info)
 {
@@ -1812,8 +1892,15 @@ int pmbus_do_probe(struct i2c_client *client, const struct i2c_device_id *id,
 		dev_err(dev, "Failed to register hwmon device\n");
 		goto out_kfree;
 	}
+
+	ret = pmbus_regulator_register(data);
+	if (ret)
+		goto out_unregister;
+
 	return 0;
 
+out_unregister:
+	hwmon_device_unregister(data->hwmon_dev);
 out_kfree:
 	kfree(data->group.attrs);
 	return ret;

include/linux/i2c/pmbus.h

@@ -40,6 +40,10 @@
 
 struct pmbus_platform_data {
 	u32 flags;		/* Device specific flags */
+
+	/* regulator support */
+	int num_regulators;
+	struct regulator_init_data *reg_init_data;
 };
 
 #endif /* _PMBUS_H_ */