[PATCH 3/3] hwmon: (lm75) Add regulator support

[Alban Bedel]

Add regulator support for boards where the sensor first need to be
powered up before it can be used.

Signed-off-by: Alban Bedel <alban.be...@aerq.com>
---
 drivers/hwmon/lm75.c | 31 +++++++++++++++++++++++++++++--
 1 file changed, 29 insertions(+), 2 deletions(-)

diff --git a/drivers/hwmon/lm75.c b/drivers/hwmon/lm75.c
index ba0be48aeadd..b673f8d2ef20 100644
--- a/drivers/hwmon/lm75.c
+++ b/drivers/hwmon/lm75.c
@@ -17,6 +17,7 @@
 #include <linux/of.h>
 #include <linux/regmap.h>
 #include <linux/util_macros.h>
+#include <linux/regulator/consumer.h>
 #include "lm75.h"
 
 /*
@@ -101,6 +102,7 @@ static const unsigned short normal_i2c[] = { 0x48, 0x49, 
0x4a, 0x4b, 0x4c,
 struct lm75_data {
        struct i2c_client               *client;
        struct regmap                   *regmap;
+       struct regulator                *vs;
        u8                              orig_conf;
        u8                              current_conf;
        u8                              resolution;     /* In bits, 9 to 16 */
@@ -540,6 +542,8 @@ static void lm75_remove(void *data)
        struct i2c_client *client = lm75->client;
 
        i2c_smbus_write_byte_data(client, LM75_REG_CONF, lm75->orig_conf);
+       if (lm75->vs)
+               regulator_disable(lm75->vs);
 }
 
 static int
@@ -567,6 +571,14 @@ lm75_probe(struct i2c_client *client, const struct 
i2c_device_id *id)
        data->client = client;
        data->kind = kind;
 
+       data->vs = devm_regulator_get_optional(dev, "vs");
+       if (IS_ERR(data->vs)) {
+               if (PTR_ERR(data->vs) == -ENODEV)
+                       data->vs = NULL;
+               else
+                       return PTR_ERR(data->vs);
+       }
+
        data->regmap = devm_regmap_init_i2c(client, &lm75_regmap_config);
        if (IS_ERR(data->regmap))
                return PTR_ERR(data->regmap);
@@ -581,11 +593,21 @@ lm75_probe(struct i2c_client *client, const struct 
i2c_device_id *id)
        data->sample_time = data->params->default_sample_time;
        data->resolution = data->params->default_resolution;
 
+       /* Enable the power */
+       if (data->vs) {
+               err = regulator_enable(data->vs);
+               if (err) {
+                       dev_err(dev, "failed to enable regulator: %d\n", err);
+                       return err;
+               }
+       }
+
        /* Cache original configuration */
        status = i2c_smbus_read_byte_data(client, LM75_REG_CONF);
        if (status < 0) {
                dev_dbg(dev, "Can't read config? %d\n", status);
-               return status;
+               err = status;
+               goto disable_regulator;
        }
        data->orig_conf = status;
        data->current_conf = status;
@@ -593,7 +615,7 @@ lm75_probe(struct i2c_client *client, const struct 
i2c_device_id *id)
        err = lm75_write_config(data, data->params->set_mask,
                                data->params->clr_mask);
        if (err)
-               return err;
+               goto disable_regulator;
 
        err = devm_add_action_or_reset(dev, lm75_remove, data);
        if (err)
@@ -608,6 +630,11 @@ lm75_probe(struct i2c_client *client, const struct 
i2c_device_id *id)
        dev_info(dev, "%s: sensor '%s'\n", dev_name(hwmon_dev), client->name);
 
        return 0;
+
+disable_regulator:
+       if (data->vs)
+               regulator_disable(data->vs);
+       return err;
 }
 
 static const struct i2c_device_id lm75_ids[] = {
-- 
2.25.1