diff mbox series

staging: iio: frequency: ad9834: Use div64_ul instead of do_div

Message ID Y1r8gMR8VBG/4A4P@ubunlion
State New
Headers
Series staging: iio: frequency: ad9834: Use div64_ul instead of do_div |

Commit Message

Deepak R Varma Oct. 27, 2022, 9:47 p.m. UTC 
  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@mailo.com>
---
 drivers/staging/iio/frequency/ad9834.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

--
2.34.1

Comments

Sa, Nuno Oct. 28, 2022, 10:11 a.m. UTC | #1 
> -----Original Message-----
> From: Deepak R Varma <drv@mailo.com>
> Sent: Thursday, October 27, 2022 11:48 PM
> To: Lars-Peter Clausen <lars@metafoo.de>; Hennerich, Michael
> <Michael.Hennerich@analog.com>; Jonathan Cameron <jic23@kernel.org>;
> Greg Kroah-Hartman <gregkh@linuxfoundation.org>; linux-
> iio@vger.kernel.org; linux-staging@lists.linux.dev; linux-
> kernel@vger.kernel.org
> Subject: [PATCH] staging: iio: frequency: ad9834: Use div64_ul instead of
> do_div
> 
> [External]
> 
> 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@mailo.com>
> ---

Reviewed-by: Nuno Sá <nuno.sa@analog.com>
diff mbox series

Patch

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,