From 0e2af0fc30eca0ae92abcf1c8fc7be94a8cc95c3 Mon Sep 17 00:00:00 2001 From: Archit Anant Date: Wed, 18 Feb 2026 18:23:27 +0530 Subject: [PATCH] staging: iio: impedance-analyzer: ad5933: use div64_ul() instead of do_div() 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 Reviewed-by: Andy Shevchenko Signed-off-by: Jonathan Cameron --- drivers/staging/iio/impedance-analyzer/ad5933.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/staging/iio/impedance-analyzer/ad5933.c b/drivers/staging/iio/impedance-analyzer/ad5933.c index 85a4223295cd..f6d3d98b6c6a 100644 --- a/drivers/staging/iio/impedance-analyzer/ad5933.c +++ b/drivers/staging/iio/impedance-analyzer/ad5933.c @@ -5,6 +5,7 @@ * Copyright 2011 Analog Devices Inc. */ +#include #include #include #include @@ -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: