[PATCH] iio: adc: rockchip_saradc: just get referenced voltage once at probe

[Simon Xue]

From: David Wu <david.wu at rock-chips.com>

The referenced voltage is not changed after initiation, so just only
get referenced voltage once.

Signed-off-by: Simon Xue <xxm at rock-chips.com>
Signed-off-by: David Wu <david.wu at rock-chips.com>
---
 drivers/iio/adc/rockchip_saradc.c | 16 +++++++++-------
 1 file changed, 9 insertions(+), 7 deletions(-)

diff --git a/drivers/iio/adc/rockchip_saradc.c b/drivers/iio/adc/rockchip_saradc.c
index f3eb8d2e50dc..cd33c0b9d3eb 100644
--- a/drivers/iio/adc/rockchip_saradc.c
+++ b/drivers/iio/adc/rockchip_saradc.c
@@ -49,6 +49,7 @@ struct rockchip_saradc {
 	struct clk		*clk;
 	struct completion	completion;
 	struct regulator	*vref;
+	int			uv_vref;
 	struct reset_control	*reset;
 	const struct rockchip_saradc_data *data;
 	u16			last_val;
@@ -105,13 +106,7 @@ static int rockchip_saradc_read_raw(struct iio_dev *indio_dev,
 		mutex_unlock(&indio_dev->mlock);
 		return IIO_VAL_INT;
 	case IIO_CHAN_INFO_SCALE:
-		ret = regulator_get_voltage(info->vref);
-		if (ret < 0) {
-			dev_err(&indio_dev->dev, "failed to get voltage\n");
-			return ret;
-		}
-
-		*val = ret / 1000;
+		*val = info->uv_vref / 1000;
 		*val2 = chan->scan_type.realbits;
 		return IIO_VAL_FRACTIONAL_LOG2;
 	default:
@@ -410,6 +405,13 @@ static int rockchip_saradc_probe(struct platform_device *pdev)
 		return ret;
 	}
 
+	info->uv_vref = regulator_get_voltage(info->vref);
+	if (info->uv_vref < 0) {
+		dev_err(&pdev->dev, "failed to get voltage\n");
+		ret = info->uv_vref;
+		return ret;
+	}
+
 	ret = clk_prepare_enable(info->pclk);
 	if (ret < 0) {
 		dev_err(&pdev->dev, "failed to enable pclk\n");
-- 
2.25.1