[PATCH V6] iio: light: isl29018: add optional vcc regulator operation support

[Anson Huang <anson.huang@xxxxxxx>]

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 vcc regulator operation support.

Signed-off-by: Anson Huang <Anson.Huang@xxxxxxx>
---
ChangeLog since V5:
	Since the dt-binding doc states the power supply name is "vdd" and many dts files already using
	"vcc" as the power supply name, althoug it does NOT match the datasheet which has "vdd", to make
	it NOT breaking existing dtb files, just use "vcc" as the regulator name.
---
 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..76c3a48 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,
@@ -735,6 +737,19 @@ static int isl29018_probe(struct i2c_client *client,
 
 	mutex_init(&chip->lock);
 
+	chip->vcc_reg = devm_regulator_get_optional(&client->dev, "vcc");
+	if (!IS_ERR(chip->vcc_reg)) {
+		err = regulator_enable(chip->vcc_reg);
+		if (err) {
+			dev_err(&client->dev, "failed to enable VCC regulator\n");
+			return err;
+		}
+	} else {
+		err = PTR_ERR(chip->vcc_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->vcc_reg))
+		regulator_disable(chip->vcc_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->vcc_reg)) {
+		ret = regulator_disable(chip->vcc_reg);
+		if (ret) {
+			dev_err(dev, "failed to disable VCC 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->vcc_reg)) {
+		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