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>

2 files changed, 113 insertions, 0 deletions

diff --git a/drivers/hwmon/pmbus/pmbus.h b/drivers/hwmon/pmbus/pmbus.h
index 3ae79a7d1b00..89a23ff836e7 100644
--- a/drivers/hwmon/pmbus/pmbus.h
+++ b/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
 
@@ -186,6 +188,11 @@
 #define PMBUS_VIRT_STATUS_VMON          (PMBUS_VIRT_BASE + 35)
 
 /*
+ * OPERATION
+ */
+#define PB_OPERATION_CONTROL_ON         (1<<7)
+
+/*
  * CAPABILITY
  */
 #define PB_CAPABILITY_SMBALERT          (1<<4)
@@ -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);
diff --git a/drivers/hwmon/pmbus/pmbus_core.c b/drivers/hwmon/pmbus/pmbus_core.c
index d6c3701eb7f9..f2e47c7dd808 100644
--- a/drivers/hwmon/pmbus/pmbus_core.c
+++ b/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;