hwmon: (lm90) Add power control

The device lm90 can be controlled by the vcc rail.
Adding the regulator support to power on/off the vcc rail.
Enable the "vcc" regulator before accessing the device.

[JD: Rename variables to avoid confusion with registers.]

Signed-off-by: Wei Ni <wni@nvidia.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>

1 files changed, 19 insertions, 0 deletions

diff --git a/drivers/hwmon/lm90.c b/drivers/hwmon/lm90.c
index 03735c490891..4c4c1421bf28 100644
--- a/drivers/hwmon/lm90.c
+++ b/drivers/hwmon/lm90.c
@@ -95,6 +95,7 @@
 #include <linux/mutex.h>
 #include <linux/sysfs.h>
 #include <linux/interrupt.h>
+#include <linux/regulator/consumer.h>
 
 /*
  * Addresses to scan
@@ -366,6 +367,7 @@ enum lm90_temp11_reg_index {
 struct lm90_data {
         struct device *hwmon_dev;
         struct mutex update_lock;
+        struct regulator *regulator;
         char valid; /* zero until following fields are valid */
         unsigned long last_updated; /* in jiffies */
         int kind;
@@ -1516,8 +1518,20 @@ static int lm90_probe(struct i2c_client *client,
         struct device *dev = &client->dev;
         struct i2c_adapter *adapter = to_i2c_adapter(dev->parent);
         struct lm90_data *data;
+        struct regulator *regulator;
         int err;
 
+        regulator = devm_regulator_get(dev, "vcc");
+        if (IS_ERR(regulator))
+                return PTR_ERR(regulator);
+
+        err = regulator_enable(regulator);
+        if (err < 0) {
+                dev_err(&client->dev,
+                        "Failed to enable regulator: %d\n", err);
+                return err;
+        }
+
         data = devm_kzalloc(&client->dev, sizeof(struct lm90_data), GFP_KERNEL);
         if (!data)
                 return -ENOMEM;
@@ -1525,6 +1539,8 @@ static int lm90_probe(struct i2c_client *client,
         i2c_set_clientdata(client, data);
         mutex_init(&data->update_lock);
 
+        data->regulator = regulator;
+
         /* Set the device type */
         data->kind = id->driver_data;
         if (data->kind == adm1032) {
@@ -1604,6 +1620,8 @@ exit_remove_files:
         lm90_remove_files(client, data);
 exit_restore:
         lm90_restore_conf(client, data);
+        regulator_disable(data->regulator);
+
         return err;
 }
 
@@ -1614,6 +1632,7 @@ static int lm90_remove(struct i2c_client *client)
         hwmon_device_unregister(data->hwmon_dev);
         lm90_remove_files(client, data);
         lm90_restore_conf(client, data);
+        regulator_disable(data->regulator);
 
         return 0;
 }