[PATCH v1 4/9] iio: afe: rescale: add offset support

[Liam Beguin <liambeguin@gmail.com>]

From: Liam Beguin <lvb@xiphos.com>

This is a preparatory change required for the addition of temperature
sensing front ends.

Signed-off-by: Liam Beguin <lvb@xiphos.com>
---
 drivers/iio/afe/iio-rescale.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/drivers/iio/afe/iio-rescale.c b/drivers/iio/afe/iio-rescale.c
index 4d0813b274d1..3bd1f11f21db 100644
--- a/drivers/iio/afe/iio-rescale.c
+++ b/drivers/iio/afe/iio-rescale.c
@@ -31,6 +31,7 @@ struct rescale {
 	struct iio_chan_spec_ext_info *ext_info;
 	s32 numerator;
 	s32 denominator;
+	s32 offset;
 };
 
 static int rescale_read_raw(struct iio_dev *indio_dev,
@@ -52,6 +53,10 @@ static int rescale_read_raw(struct iio_dev *indio_dev,
 		*val2 = rescale->denominator;
 
 		return IIO_VAL_FRACTIONAL;
+	case IIO_CHAN_INFO_OFFSET:
+		*val = rescale->offset;
+
+		return IIO_VAL_INT;
 	default:
 		return -EINVAL;
 	}
@@ -119,8 +124,10 @@ static int rescale_configure_channel(struct device *dev,
 		return -EINVAL;
 	}
 
-	chan->info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
-		BIT(IIO_CHAN_INFO_SCALE);
+	chan->info_mask_separate =
+		BIT(IIO_CHAN_INFO_RAW) |
+		BIT(IIO_CHAN_INFO_SCALE) |
+		BIT(IIO_CHAN_INFO_OFFSET);
 
 	if (iio_channel_has_available(schan, IIO_CHAN_INFO_RAW))
 		chan->info_mask_separate_available |= BIT(IIO_CHAN_INFO_RAW);
@@ -280,6 +287,7 @@ static int rescale_probe(struct platform_device *pdev)
 	rescale->cfg = of_device_get_match_data(dev);
 	rescale->numerator = 1;
 	rescale->denominator = 1;
+	rescale->offset = 0;
 
 	ret = rescale->cfg->props(dev, rescale);
 	if (ret)
-- 
2.30.1.489.g328c10930387