mirrors/linux
2
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git synced 2026-05-16 17:12:50 -04:00
Code Issues Packages Projects Releases Wiki Activity

staging: iio: impedance-analyzer: ad5933: use div64_ul() instead of do_div()

Browse Source 
Replace do_div() with div64_ul() since the remainder is not used.
div64_ul() is the preferred API for 64-bit by 32-bit division when
only the quotient is needed.

Also replace explicit casting and shifting with the BIT_ULL(27) macro
for clarity.

Note: A mathematical simplification to `(freq * BIT_ULL(29)) / mclk` was
suggested during review to improve precision. However, as confirmed by
maintainers, the original driver's truncation via `(mclk / 4)` might
be intentional or relied upon by userspace. Since hardware is not
available for verification, this patch preserves the original logic
to avoid regression risk in the absence of testing.

Issue identified by coccicheck using do_div.cocci.

Signed-off-by: Archit Anant <architanant5@gmail.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@intel.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
This commit is contained in:
Archit Anant
2026-02-18 18:23:27 +05:30
committed by Jonathan Cameron
parent 08eea726f4
commit 0e2af0fc30
1 changed files with 2 additions and 2 deletions
Download Patch File Download Diff File Expand all files Collapse all files

4
drivers/staging/iio/impedance-analyzer/ad5933.c
View File

@@ -5,6 +5,7 @@
* Copyright 2011 Analog Devices Inc.
*/
#include <linux/bits.h>
#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/device.h>
@@ -194,8 +195,7 @@ static int ad5933_set_freq(struct ad5933_state *st,
u8 d8[4];
} dat;
freqreg = (u64)freq * (u64)(1 << 27);
do_div(freqreg, st->mclk_hz / 4);
freqreg = div64_ul(BIT_ULL(27) * freq, st->mclk_hz / 4);
switch (reg) {
case AD5933_REG_FREQ_START: