[PATCH V5 2/2] iio: light: isl29018: add optional vdd regulator operation support

[Anson Huang <anson.huang@nxp.com>]

The light sensor's power supply could be controlled 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 optional vdd regulator operation support.

Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
---
ChangeLog since V4:
	Since ONLY isl29018 has two power supplies and they are MUST shorted externally, so they can be
	treated as one power supply as well, using one regulator for driver.
---
 drivers/iio/light/isl29018.c | 47 +++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 44 insertions(+), 3 deletions(-)

diff --git a/drivers/iio/light/isl29018.c b/drivers/iio/light/isl29018.c
index b45400f..5e3d1c1 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	*vdd_reg;
 };
 
 static int isl29018_set_integration_time(struct isl29018_chip *chip,
@@ -735,6 +737,19 @@ static int isl29018_probe(struct i2c_client *client,
 
 	mutex_init(&chip->lock);
 
+	chip->vdd_reg = devm_regulator_get_optional(&client->dev, "vdd");
+	if (!IS_ERR(chip->vdd_reg)) {
+		err = regulator_enable(chip->vdd_reg);
+		if (err) {
+			dev_err(&client->dev, "failed to enable VDD regulator\n");
+			return err;
+		}
+	} else {
+		err = PTR_ERR(chip->vdd_reg);
+		if (err != -ENODEV)
+			return err;
+	}
+
 	chip->type = dev_id;
 	chip->calibscale = 1;
 	chip->ucalibscale = 0;
@@ -747,12 +762,12 @@ static int isl29018_probe(struct i2c_client *client,
 	if (IS_ERR(chip->regmap)) {
 		err = PTR_ERR(chip->regmap);
 		dev_err(&client->dev, "regmap initialization fails: %d\n", err);
-		return err;
+		goto disable_regulator;
 	}
 
 	err = isl29018_chip_init(chip);
 	if (err)
-		return err;
+		goto disable_regulator;
 
 	indio_dev->info = isl29018_chip_info_tbl[dev_id].indio_info;
 	indio_dev->channels = isl29018_chip_info_tbl[dev_id].channels;
@@ -761,13 +776,22 @@ static int isl29018_probe(struct i2c_client *client,
 	indio_dev->dev.parent = &client->dev;
 	indio_dev->modes = INDIO_DIRECT_MODE;
 
-	return devm_iio_device_register(&client->dev, indio_dev);
+	err = devm_iio_device_register(&client->dev, indio_dev);
+	if (!err)
+		return 0;
+
+disable_regulator:
+	if (!IS_ERR(chip->vdd_reg))
+		regulator_disable(chip->vdd_reg);
+
+	return err;
 }
 
 #ifdef CONFIG_PM_SLEEP
 static int isl29018_suspend(struct device *dev)
 {
 	struct isl29018_chip *chip = iio_priv(dev_get_drvdata(dev));
+	int ret;
 
 	mutex_lock(&chip->lock);
 
@@ -777,6 +801,14 @@ static int isl29018_suspend(struct device *dev)
 	 * So we do not have much to do here.
 	 */
 	chip->suspended = true;
+	if (!IS_ERR(chip->vdd_reg)) {
+		ret = regulator_disable(chip->vdd_reg);
+		if (ret) {
+			dev_err(dev, "failed to disable VDD regulator\n");
+			mutex_unlock(&chip->lock);
+			return ret;
+		}
+	}
 
 	mutex_unlock(&chip->lock);
 
@@ -790,6 +822,15 @@ static int isl29018_resume(struct device *dev)
 
 	mutex_lock(&chip->lock);
 
+	if (!IS_ERR(chip->vdd_reg)) {
+		err = regulator_enable(chip->vdd_reg);
+		if (err) {
+			dev_err(dev, "failed to enable VDD regulator\n");
+			mutex_unlock(&chip->lock);
+			return err;
+		}
+	}
+
 	err = isl29018_chip_init(chip);
 	if (!err)
 		chip->suspended = false;
-- 
2.7.4