[PATCH V9] iio: light: isl29018: add vcc regulator operation support

[Anson Huang]

The light sensor's power supply could be controllable by regulator
on some platforms, such as i.MX6Q-SABRESD board, the light sensor
isl29023's power supply is controlled by a GPIO fixed regulator,
need to make sure the regulator is enabled before any operation of
sensor, this patch adds vcc regulator operation support.

Signed-off-by: Anson Huang <anson.hu...@nxp.com>
---
ChangeLog since V8:
  - use devm_add_action_or_reset instead of devm_add_action to avoid calling 
regulator disable when failed;
---
 drivers/iio/light/isl29018.c | 46 +++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 45 insertions(+), 1 deletion(-)

diff --git a/drivers/iio/light/isl29018.c b/drivers/iio/light/isl29018.c
index b45400f..846df4d 100644
--- a/drivers/iio/light/isl29018.c
+++ b/drivers/iio/light/isl29018.c
@@ -23,6 +23,7 @@
 #include <linux/mutex.h>
 #include <linux/delay.h>
 #include <linux/regmap.h>
+#include <linux/regulator/consumer.h>
 #include <linux/slab.h>
 #include <linux/iio/iio.h>
 #include <linux/iio/sysfs.h>
@@ -95,6 +96,7 @@ struct isl29018_chip {
        struct isl29018_scale   scale;
        int                     prox_scheme;
        bool                    suspended;
+       struct regulator        *vcc_reg;
 };
 
 static int isl29018_set_integration_time(struct isl29018_chip *chip,
@@ -708,6 +710,16 @@ static const char *isl29018_match_acpi_device(struct 
device *dev, int *data)
        return dev_name(dev);
 }
 
+static void isl29018_disable_regulator_action(void *_data)
+{
+       struct isl29018_chip *chip = _data;
+       int err;
+
+       err = regulator_disable(chip->vcc_reg);
+       if (err)
+               pr_err("failed to disable isl29018's VCC regulator!\n");
+}
+
 static int isl29018_probe(struct i2c_client *client,
                          const struct i2c_device_id *id)
 {
@@ -742,6 +754,27 @@ static int isl29018_probe(struct i2c_client *client,
        chip->scale = isl29018_scales[chip->int_time][0];
        chip->suspended = false;
 
+       chip->vcc_reg = devm_regulator_get(&client->dev, "vcc");
+       if (IS_ERR(chip->vcc_reg)) {
+               err = PTR_ERR(chip->vcc_reg);
+               if (err != -EPROBE_DEFER)
+                       dev_err(&client->dev, "failed to get VCC regulator!\n");
+               return err;
+       }
+
+       err = regulator_enable(chip->vcc_reg);
+       if (err) {
+               dev_err(&client->dev, "failed to enable VCC regulator!\n");
+               return err;
+       }
+
+       err = devm_add_action_or_reset(&client->dev, 
isl29018_disable_regulator_action,
+                                chip);
+       if (err) {
+               dev_err(&client->dev, "failed to setup regulator cleanup 
action!\n");
+               return err;
+       }
+
        chip->regmap = devm_regmap_init_i2c(client,
                                isl29018_chip_info_tbl[dev_id].regmap_cfg);
        if (IS_ERR(chip->regmap)) {
@@ -768,6 +801,7 @@ static int isl29018_probe(struct i2c_client *client,
 static int isl29018_suspend(struct device *dev)
 {
        struct isl29018_chip *chip = iio_priv(dev_get_drvdata(dev));
+       int ret;
 
        mutex_lock(&chip->lock);
 
@@ -777,10 +811,13 @@ static int isl29018_suspend(struct device *dev)
         * So we do not have much to do here.
         */
        chip->suspended = true;
+       ret = regulator_disable(chip->vcc_reg);
+       if (ret)
+               dev_err(dev, "failed to disable VCC regulator\n");
 
        mutex_unlock(&chip->lock);
 
-       return 0;
+       return ret;
 }
 
 static int isl29018_resume(struct device *dev)
@@ -790,6 +827,13 @@ static int isl29018_resume(struct device *dev)
 
        mutex_lock(&chip->lock);
 
+       err = regulator_enable(chip->vcc_reg);
+       if (err) {
+               dev_err(dev, "failed to enable VCC regulator\n");
+               mutex_unlock(&chip->lock);
+               return err;
+       }
+
        err = isl29018_chip_init(chip);
        if (!err)
                chip->suspended = false;
-- 
2.7.4