[PATCH v2] staging: iio: frequency: ad9834: Use div64_ul instead of do_div

From: Deepak R Varma
Date: Thu Oct 27 2022 - 18:00:12 EST


do_div() does a 64-by-32 division. Here the divisor is an unsigned long
which on some platforms is 64 bit wide. So use div64_ul instead of do_div
to avoid a possible truncation. Issue identified using the
coccicheck tool.

Signed-off-by: Deepak R Varma <drv@xxxxxxxxx>
---

Changes in v2:
1. No functional change.
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drivers/staging/iio/frequency/ad9834.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/staging/iio/frequency/ad9834.c b/drivers/staging/iio/frequency/ad9834.c
index 285df0e489a6..3917a76e7976 100644
--- a/drivers/staging/iio/frequency/ad9834.c
+++ b/drivers/staging/iio/frequency/ad9834.c
@@ -102,8 +102,7 @@ static unsigned int ad9834_calc_freqreg(unsigned long mclk, unsigned long fout)
{
unsigned long long freqreg = (u64)fout * (u64)BIT(AD9834_FREQ_BITS);

- do_div(freqreg, mclk);
- return freqreg;
+ return div64_ul(freqreg, mclk);
}

static int ad9834_write_frequency(struct ad9834_state *st,
--
2.34.1