[PATCH] staging: iio: frequency: ad9832: Use div64_ul instead of do_div

From: Deepak R Varma
Date: Thu Oct 27 2022 - 17:54:59 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>
---
drivers/staging/iio/frequency/ad9832.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/staging/iio/frequency/ad9832.c b/drivers/staging/iio/frequency/ad9832.c
index 6f9eebd6c7ee..a8409f6b1c4c 100644
--- a/drivers/staging/iio/frequency/ad9832.c
+++ b/drivers/staging/iio/frequency/ad9832.c
@@ -122,8 +122,7 @@ static unsigned long ad9832_calc_freqreg(unsigned long mclk, unsigned long fout)
{
unsigned long long freqreg = (u64)fout *
(u64)((u64)1L << AD9832_FREQ_BITS);
- do_div(freqreg, mclk);
- return freqreg;
+ return div64_ul(freqreg, mclk);
}

static int ad9832_write_frequency(struct ad9832_state *st,
--
2.34.1