[PATCH 04/19] staging: iio: isl29028: add power management support

[Brian Masney]

This patch adds power management support to the isl29028 driver.

Signed-off-by: Brian Masney <masneyb at onstation.org>
---
 drivers/staging/iio/light/isl29028.c | 59 ++++++++++++++++++++++++++++++++++++
 1 file changed, 59 insertions(+)

diff --git a/drivers/staging/iio/light/isl29028.c b/drivers/staging/iio/light/isl29028.c
index 4f819a8..e96a8cb 100644
--- a/drivers/staging/iio/light/isl29028.c
+++ b/drivers/staging/iio/light/isl29028.c
@@ -75,6 +75,7 @@ struct isl29028_chip {
 
 	int			lux_scale;
 	enum isl29028_als_ir_mode	als_ir_mode;
+	bool				suspended;
 };
 
 static int isl29028_set_proxim_sampling(struct isl29028_chip *chip,
@@ -274,6 +275,12 @@ static int isl29028_write_raw(struct iio_dev *indio_dev,
 	int ret = -EINVAL;
 
 	mutex_lock(&chip->lock);
+
+	if (chip->suspended) {
+		ret = -EBUSY;
+		goto write_done;
+	}
+
 	switch (chan->type) {
 	case IIO_PROXIMITY:
 		if (mask != IIO_CHAN_INFO_SAMP_FREQ) {
@@ -322,6 +329,8 @@ static int isl29028_write_raw(struct iio_dev *indio_dev,
 		dev_err(dev, "Unsupported channel type\n");
 		break;
 	}
+
+write_done:
 	mutex_unlock(&chip->lock);
 	return ret;
 }
@@ -335,6 +344,12 @@ static int isl29028_read_raw(struct iio_dev *indio_dev,
 	int ret = -EINVAL;
 
 	mutex_lock(&chip->lock);
+
+	if (chip->suspended) {
+		ret = -EBUSY;
+		goto read_done;
+	}
+
 	switch (mask) {
 	case IIO_CHAN_INFO_RAW:
 	case IIO_CHAN_INFO_PROCESSED:
@@ -374,6 +389,8 @@ static int isl29028_read_raw(struct iio_dev *indio_dev,
 		dev_err(dev, "mask value 0x%08lx not supported\n", mask);
 		break;
 	}
+
+read_done:
 	mutex_unlock(&chip->lock);
 	return ret;
 }
@@ -437,6 +454,9 @@ static int isl29028_chip_init_and_power_on(struct isl29028_chip *chip)
 	ret = isl29028_set_als_scale(chip, chip->lux_scale);
 	if (ret < 0)
 		dev_err(dev, "setting als scale failed, err = %d\n", ret);
+
+	chip->suspended = false;
+
 	return ret;
 }
 
@@ -479,6 +499,7 @@ static int isl29028_probe(struct i2c_client *client,
 
 	i2c_set_clientdata(client, indio_dev);
 	mutex_init(&chip->lock);
+	chip->suspended = true;
 
 	chip->regmap = devm_regmap_init_i2c(client, &isl29028_regmap_config);
 	if (IS_ERR(chip->regmap)) {
@@ -530,6 +551,43 @@ static int isl29028_probe(struct i2c_client *client,
 	return 0;
 }
 
+static int __maybe_unused isl29028_suspend(struct device *dev)
+{
+	struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
+	struct isl29028_chip *chip = iio_priv(indio_dev);
+	int ret;
+
+	mutex_lock(&chip->lock);
+
+	ret = regmap_write(chip->regmap, ISL29028_REG_CONFIGURE, 0x0);
+	if (ret < 0)
+		dev_err(dev, "%s(): Error %d turning off chip\n", __func__,
+			ret);
+
+	chip->suspended = true;
+
+	mutex_unlock(&chip->lock);
+
+	return ret;
+}
+
+static int __maybe_unused isl29028_resume(struct device *dev)
+{
+	struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
+	struct isl29028_chip *chip = iio_priv(indio_dev);
+	int ret;
+
+	mutex_lock(&chip->lock);
+
+	ret = isl29028_chip_init_and_power_on(chip);
+
+	mutex_unlock(&chip->lock);
+
+	return ret;
+}
+
+static SIMPLE_DEV_PM_OPS(isl29028_pm_ops, isl29028_suspend, isl29028_resume);
+
 static const struct i2c_device_id isl29028_id[] = {
 	{"isl29028", 0},
 	{}
@@ -546,6 +604,7 @@ MODULE_DEVICE_TABLE(of, isl29028_of_match);
 static struct i2c_driver isl29028_driver = {
 	.driver  = {
 		.name = "isl29028",
+		.pm = &isl29028_pm_ops,
 		.of_match_table = isl29028_of_match,
 	},
 	.probe	 = isl29028_probe,
-- 
2.7.4