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From: Liam Beguin <liambeguin@gmail.com>
To: liambeguin@gmail.com, peda@axentia.se, jic23@kernel.org,
	lars@metafoo.de, pmeerw@pmeerw.net
Cc: linux-kernel@vger.kernel.org, linux-iio@vger.kernel.org,
	devicetree@vger.kernel.org, robh+dt@kernel.org
Subject: [PATCH v7 05/13] iio: afe: rescale: add INT_PLUS_{MICRO,NANO} support
Date: Sun,  1 Aug 2021 15:39:52 -0400	[thread overview]
Message-ID: <20210801194000.3646303-6-liambeguin@gmail.com> (raw)
In-Reply-To: <20210801194000.3646303-1-liambeguin@gmail.com>

From: Liam Beguin <lvb@xiphos.com>

Some ADCs use IIO_VAL_INT_PLUS_{NANO,MICRO} scale types.
Add support for these to allow using the iio-rescaler with them.

Signed-off-by: Liam Beguin <lvb@xiphos.com>
---
 drivers/iio/afe/iio-rescale.c | 35 +++++++++++++++++++++++++++++++++++
 1 file changed, 35 insertions(+)

diff --git a/drivers/iio/afe/iio-rescale.c b/drivers/iio/afe/iio-rescale.c
index d0669fd8eac5..615f5d9cbb8b 100644
--- a/drivers/iio/afe/iio-rescale.c
+++ b/drivers/iio/afe/iio-rescale.c
@@ -22,6 +22,9 @@ int rescale_process_scale(struct rescale *rescale, int scale_type,
 			  int *val, int *val2)
 {
 	unsigned long long tmp;
+	u32 mult;
+	u32 rem;
+	u32 neg;
 
 	switch (scale_type) {
 	case IIO_VAL_FRACTIONAL:
@@ -40,6 +43,38 @@ int rescale_process_scale(struct rescale *rescale, int scale_type,
 		tmp *= rescale->numerator;
 		do_div(tmp, 1000000000LL);
 		*val = tmp;
+		return scale_type;
+	case IIO_VAL_INT_PLUS_NANO:
+	case IIO_VAL_INT_PLUS_MICRO:
+		if (scale_type == IIO_VAL_INT_PLUS_NANO)
+			mult = 1000000000LL;
+		else
+			mult = 1000000LL;
+		/*
+		 * For IIO_VAL_INT_PLUS_{MICRO,NANO} scale types if *val OR
+		 * *val2 is negative the schan scale is negative
+		 */
+		neg = *val < 0 || *val2 < 0;
+
+		tmp = (s64)abs(*val) * abs(rescale->numerator);
+		*val = div_s64_rem(tmp, abs(rescale->denominator), &rem);
+
+		tmp = (s64)rem * mult + (s64)abs(*val2) * abs(rescale->numerator);
+		tmp = div_s64(tmp, abs(rescale->denominator));
+
+		*val += div_s64_rem(tmp, mult, val2);
+
+		/*
+		 * If only one of the rescaler elements or the schan scale is
+		 * negative, the combined scale is negative.
+		 */
+		if (neg ^ ((rescale->numerator < 0) ^ (rescale->denominator < 0))) {
+			if (*val)
+				*val = -*val;
+			else
+				*val2 = -*val2;
+		}
+
 		return scale_type;
 	default:
 		return -EOPNOTSUPP;
-- 
2.30.1.489.g328c10930387


  parent reply	other threads:[~2021-08-01 19:40 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-01 19:39 [PATCH v7 00/13] iio: afe: add temperature rescaling support Liam Beguin
2021-08-01 19:39 ` [PATCH v7 01/13] iio: inkern: apply consumer scale on IIO_VAL_INT cases Liam Beguin
2021-08-01 19:39 ` [PATCH v7 02/13] iio: inkern: apply consumer scale when no channel scale is available Liam Beguin
2021-08-01 19:39 ` [PATCH v7 03/13] iio: inkern: make a best effort on offset calculation Liam Beguin
2021-08-01 19:39 ` [PATCH v7 04/13] iio: afe: rescale: expose scale processing function Liam Beguin
2021-08-01 19:39 ` Liam Beguin [this message]
2021-08-01 19:39 ` [PATCH v7 06/13] iio: afe: rescale: add offset support Liam Beguin
2021-08-01 19:39 ` [PATCH v7 07/13] iio: afe: rescale: reduce risk of integer overflow Liam Beguin
2021-08-01 19:39 ` [PATCH v7 08/13] iio: afe: rescale: fix precision on fractional log scale Liam Beguin
2021-08-02  9:17   ` Peter Rosin
2021-08-15 22:14     ` Liam Beguin
2021-08-01 19:39 ` [PATCH v7 09/13] iio: test: add basic tests for the iio-rescale driver Liam Beguin
2021-08-01 19:39 ` [PATCH v7 10/13] iio: afe: rescale: add RTD temperature sensor support Liam Beguin
2021-08-01 19:39 ` [PATCH v7 11/13] iio: afe: rescale: add temperature transducers Liam Beguin
2021-08-01 19:39 ` [PATCH v7 12/13] dt-bindings: iio: afe: add bindings for temperature-sense-rtd Liam Beguin
2021-08-01 19:40 ` [PATCH v7 13/13] dt-bindings: iio: afe: add bindings for temperature transducers Liam Beguin

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