diff mbox series

iio: frequency: ad9523: Improve reported VCO frequency accuracy

Message ID 20190326132658.16724-1-alexandru.ardelean@analog.com (mailing list archive)
State New, archived
Headers show
Series iio: frequency: ad9523: Improve reported VCO frequency accuracy | expand

Commit Message

Alexandru Ardelean March 26, 2019, 1:26 p.m. UTC 
From: Lars-Peter Clausen <lars@metafoo.de>

To improve the accuracy of the reported VCO frequency perform all
multiplications before divisions. This reduces rounding errors and makes
sure the reported rates are accurate down to the last digit.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
---
 drivers/iio/frequency/ad9523.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)
diff mbox series

Patch

diff --git a/drivers/iio/frequency/ad9523.c b/drivers/iio/frequency/ad9523.c
index 3f9be69499ec..d2aef511189a 100644
--- a/drivers/iio/frequency/ad9523.c
+++ b/drivers/iio/frequency/ad9523.c
@@ -862,9 +862,11 @@  static int ad9523_setup(struct iio_dev *indio_dev)
 	if (ret < 0)
 		return ret;
 
-	st->vco_freq = (pdata->vcxo_freq * (pdata->pll2_freq_doubler_en ? 2 : 1)
-			/ pdata->pll2_r2_div) * AD9523_PLL2_FB_NDIV(pdata->
-			pll2_ndiv_a_cnt, pdata->pll2_ndiv_b_cnt);
+	st->vco_freq = div_u64((unsigned long long)pdata->vcxo_freq *
+			       (pdata->pll2_freq_doubler_en ? 2 : 1) *
+			       AD9523_PLL2_FB_NDIV(pdata->pll2_ndiv_a_cnt,
+						   pdata->pll2_ndiv_b_cnt),
+			       pdata->pll2_r2_div);
 
 	ret = ad9523_write(indio_dev, AD9523_PLL2_VCO_CTRL,
 		AD9523_PLL2_VCO_CALIBRATE);