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From: Liam Beguin <liambeguin@gmail.com>
To: liambeguin@gmail.com, peda@axentia.se, jic23@kernel.org, lars@metafoo.de
Cc: linux-kernel@vger.kernel.org, linux-iio@vger.kernel.org,
	devicetree@vger.kernel.org, robh+dt@kernel.org
Subject: [PATCH v9 03/14] iio: inkern: make a best effort on offset calculation
Date: Sun, 14 Nov 2021 22:43:23 -0500	[thread overview]
Message-ID: <20211115034334.1713050-4-liambeguin@gmail.com> (raw)
In-Reply-To: <20211115034334.1713050-1-liambeguin@gmail.com>

From: Liam Beguin <lvb@xiphos.com>

iio_convert_raw_to_processed_unlocked() assumes the offset is an
integer. Make a best effort to get a valid offset value for fractional
cases without breaking implicit truncations.

Fixes: 48e44ce0f881 ("iio:inkern: Add function to read the processed value")
Signed-off-by: Liam Beguin <lvb@xiphos.com>
---
 drivers/iio/inkern.c | 32 +++++++++++++++++++++++++++-----
 1 file changed, 27 insertions(+), 5 deletions(-)

diff --git a/drivers/iio/inkern.c b/drivers/iio/inkern.c
index dbe13fad3cbb..aff6d2d3447c 100644
--- a/drivers/iio/inkern.c
+++ b/drivers/iio/inkern.c
@@ -595,13 +595,35 @@ EXPORT_SYMBOL_GPL(iio_read_channel_average_raw);
 static int iio_convert_raw_to_processed_unlocked(struct iio_channel *chan,
 	int raw, int *processed, unsigned int scale)
 {
-	int scale_type, scale_val, scale_val2, offset;
+	int scale_type, scale_val, scale_val2;
+	int offset_type, offset_val, offset_val2;
 	s64 raw64 = raw;
-	int ret;
 
-	ret = iio_channel_read(chan, &offset, NULL, IIO_CHAN_INFO_OFFSET);
-	if (ret >= 0)
-		raw64 += offset;
+	offset_type = iio_channel_read(chan, &offset_val, &offset_val2,
+				       IIO_CHAN_INFO_OFFSET);
+	if (offset_type >= 0) {
+		switch (offset_type) {
+		case IIO_VAL_INT:
+			break;
+		case IIO_VAL_INT_PLUS_MICRO:
+		case IIO_VAL_INT_PLUS_NANO:
+			/*
+			 * Both IIO_VAL_INT_PLUS_MICRO and IIO_VAL_INT_PLUS_NANO
+			 * implicitely truncate the offset to it's integer form.
+			 */
+			break;
+		case IIO_VAL_FRACTIONAL:
+			offset_val /= offset_val2;
+			break;
+		case IIO_VAL_FRACTIONAL_LOG2:
+			offset_val /= (1 << offset_val2);
+			break;
+		default:
+			return -EINVAL;
+		}
+
+		raw64 += offset_val;
+	}
 
 	scale_type = iio_channel_read(chan, &scale_val, &scale_val2,
 					IIO_CHAN_INFO_SCALE);
-- 
2.32.0.452.g940fe202adcb


  parent reply	other threads:[~2021-11-15  3:47 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-11-15  3:43 [PATCH v9 00/14] iio: afe: add temperature rescaling support Liam Beguin
2021-11-15  3:43 ` [PATCH v9 01/14] iio: inkern: apply consumer scale on IIO_VAL_INT cases Liam Beguin
2021-11-15  3:43 ` [PATCH v9 02/14] iio: inkern: apply consumer scale when no channel scale is available Liam Beguin
2021-11-15  3:43 ` Liam Beguin [this message]
2021-11-15  3:43 ` [PATCH v9 04/14] iio: afe: rescale: expose scale processing function Liam Beguin
2021-11-15  3:43 ` [PATCH v9 05/14] iio: afe: rescale: add INT_PLUS_{MICRO,NANO} support Liam Beguin
2021-11-21 11:11   ` Jonathan Cameron
2021-11-15  3:43 ` [PATCH v9 06/14] iio: afe: rescale: add offset support Liam Beguin
2021-11-15  3:43 ` [PATCH v9 07/14] iio: afe: rescale: use s64 for temporary scale calculations Liam Beguin
2021-11-15  3:43 ` [PATCH v9 08/14] iio: afe: rescale: reduce risk of integer overflow Liam Beguin
2021-11-15  3:43 ` [PATCH v9 09/14] iio: afe: rescale: fix accuracy for small fractional scales Liam Beguin
2021-11-15  3:43 ` [PATCH v9 10/14] iio: test: add basic tests for the iio-rescale driver Liam Beguin
2021-11-17 15:03   ` kernel test robot
2021-11-21 11:19     ` Jonathan Cameron
2021-11-21 14:30       ` Peter Rosin
2021-11-21 17:00       ` Liam Beguin
2021-11-24 18:36   ` kernel test robot
2021-11-15  3:43 ` [PATCH v9 11/14] iio: afe: rescale: add RTD temperature sensor support Liam Beguin
2021-11-15  3:43 ` [PATCH v9 12/14] iio: afe: rescale: add temperature transducers Liam Beguin
2021-11-15  3:43 ` [PATCH v9 13/14] dt-bindings: iio: afe: add bindings for temperature-sense-rtd Liam Beguin
2021-11-15  3:43 ` [PATCH v9 14/14] dt-bindings: iio: afe: add bindings for temperature transducers Liam Beguin
2021-11-21 11:25 ` [PATCH v9 00/14] iio: afe: add temperature rescaling support Jonathan Cameron
2021-11-21 17:30   ` Liam Beguin
2021-11-22  0:53 ` Peter Rosin
2021-11-23 20:28   ` Jonathan Cameron
2021-11-27 20:27   ` Liam Beguin
2021-11-28  9:17     ` Peter Rosin
2021-11-30 18:52       ` Liam Beguin

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