[PATCH v2 6/8] 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 | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/drivers/iio/afe/iio-rescale.c b/drivers/iio/afe/iio-rescale.c
index e34148d39b39..3d445c76dbb2 100644
--- a/drivers/iio/afe/iio-rescale.c
+++ b/drivers/iio/afe/iio-rescale.c
@@ -32,6 +32,7 @@ struct rescale {
 	bool chan_processed;
 	s32 numerator;
 	s32 denominator;
+	s32 offset;
 };
 
 static int rescale_read_raw(struct iio_dev *indio_dev,
@@ -86,6 +87,10 @@ static int rescale_read_raw(struct iio_dev *indio_dev,
 		default:
 			return -EOPNOTSUPP;
 		}
+	case IIO_CHAN_INFO_OFFSET:
+		*val = rescale->offset;
+
+		return IIO_VAL_INT;
 	default:
 		return -EINVAL;
 	}
@@ -165,6 +170,9 @@ static int rescale_configure_channel(struct device *dev,
 	chan->info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
 		BIT(IIO_CHAN_INFO_SCALE);
 
+	if (rescale->offset)
+	    chan->info_mask_separate |= BIT(IIO_CHAN_INFO_OFFSET);
+
 	/*
 	 * Using .read_avail() is fringe to begin with and makes no sense
 	 * whatsoever for processed channels, so we make sure that this cannot
@@ -329,6 +337,7 @@ 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