[PATCH v5 3/4] iio: adc: ti-ads7950: switch to using devm_regulator_get_enable_read_voltage()

[Dmitry Torokhov <dmitry.torokhov@gmail.com>]

The regulator is enabled for the entire time the driver is bound to the
device, and we only need to access it to fetch voltage, which can be
done at probe time.

Switch to using devm_regulator_get_enable_read_voltage() which
simplifies probing and unbinding code.

Suggested-by: David Lechner <dlechner@baylibre.com>
Reviewed-by: Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
---
 drivers/iio/adc/ti-ads7950.c | 48 ++++++++++++--------------------------------
 1 file changed, 13 insertions(+), 35 deletions(-)

diff --git a/drivers/iio/adc/ti-ads7950.c b/drivers/iio/adc/ti-ads7950.c
index c31c706c92a9..0b98c8e7385d 100644
--- a/drivers/iio/adc/ti-ads7950.c
+++ b/drivers/iio/adc/ti-ads7950.c
@@ -334,19 +334,9 @@ static int ti_ads7950_scan_direct(struct iio_dev *indio_dev, unsigned int ch)
 	return st->single_rx;
 }
 
-static int ti_ads7950_get_range(struct ti_ads7950_state *st)
+static unsigned int ti_ads7950_get_range(struct ti_ads7950_state *st)
 {
-	int vref;
-
-	if (st->vref_mv) {
-		vref = st->vref_mv;
-	} else {
-		vref = regulator_get_voltage(st->reg);
-		if (vref < 0)
-			return vref;
-
-		vref /= 1000;
-	}
+	unsigned int vref = st->vref_mv;
 
 	if (st->cmd_settings_bitmask & TI_ADS7950_CR_RANGE_5V)
 		vref *= 2;
@@ -375,11 +365,7 @@ static int ti_ads7950_read_raw(struct iio_dev *indio_dev,
 
 		return IIO_VAL_INT;
 	case IIO_CHAN_INFO_SCALE:
-		ret = ti_ads7950_get_range(st);
-		if (ret < 0)
-			return ret;
-
-		*val = ret;
+		*val = ti_ads7950_get_range(st);
 		*val2 = (1 << chan->scan_type.realbits) - 1;
 
 		return IIO_VAL_FRACTIONAL;
@@ -573,30 +559,25 @@ static int ti_ads7950_probe(struct spi_device *spi)
 	spi_message_init_with_transfers(&st->scan_single_msg,
 					st->scan_single_xfer, 3);
 
-	/* Use hard coded value for reference voltage in ACPI case */
-	if (ACPI_COMPANION(&spi->dev))
-		st->vref_mv = TI_ADS7950_VA_MV_ACPI_DEFAULT;
-
 	mutex_init(&st->slock);
 
-	st->reg = devm_regulator_get(&spi->dev, "vref");
-	if (IS_ERR(st->reg)) {
-		ret = dev_err_probe(&spi->dev, PTR_ERR(st->reg),
-				     "Failed to get regulator \"vref\"\n");
-		goto error_destroy_mutex;
-	}
+	/* Use hard coded value for reference voltage in ACPI case */
+	if (ACPI_COMPANION(&spi->dev)) {
+		st->vref_mv = TI_ADS7950_VA_MV_ACPI_DEFAULT;
+	} else {
+		ret = devm_regulator_get_enable_read_voltage(&spi->dev, "vref");
+		if (ret < 0)
+			return dev_err_probe(&spi->dev, ret,
+					     "Failed to get regulator \"vref\"\n");
 
-	ret = regulator_enable(st->reg);
-	if (ret) {
-		dev_err(&spi->dev, "Failed to enable regulator \"vref\"\n");
-		goto error_destroy_mutex;
+		st->vref_mv = ret / 1000;
 	}
 
 	ret = iio_triggered_buffer_setup(indio_dev, NULL,
 					 &ti_ads7950_trigger_handler, NULL);
 	if (ret) {
 		dev_err(&spi->dev, "Failed to setup triggered buffer\n");
-		goto error_disable_reg;
+		goto error_destroy_mutex;
 	}
 
 	ret = ti_ads7950_init_hw(st);
@@ -636,8 +617,6 @@ static int ti_ads7950_probe(struct spi_device *spi)
 	iio_device_unregister(indio_dev);
 error_cleanup_ring:
 	iio_triggered_buffer_cleanup(indio_dev);
-error_disable_reg:
-	regulator_disable(st->reg);
 error_destroy_mutex:
 	mutex_destroy(&st->slock);
 
@@ -652,7 +631,6 @@ static void ti_ads7950_remove(struct spi_device *spi)
 	gpiochip_remove(&st->chip);
 	iio_device_unregister(indio_dev);
 	iio_triggered_buffer_cleanup(indio_dev);
-	regulator_disable(st->reg);
 	mutex_destroy(&st->slock);
 }
 

-- 
2.53.0.1213.gd9a14994de-goog