Hi Maxime, FYI, the error/warning still remains. tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master head: b81b1829e7e39f6cebdf6e4d5484eacbceda8554 commit: 8ca011ef4af48a7af7b15afd8a4a44039dd04cea clk: bcm-2835: Remove rounding up the dividers date: 4 months ago config: arm-randconfig-r006-20220213 (https://download.01.org/0day-ci/archive/20220213/202202132034.ZltYqjTa-lk...) compiler: clang version 15.0.0 (https://github.com/llvm/llvm-project 478c237e21b2c3a83e46f26fcbeb3876682f9b14) reproduce (this is a W=1 build): wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross chmod +x ~/bin/make.cross # install arm cross compiling tool for clang build # apt-get install binutils-arm-linux-gnueabi # https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit... git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git git fetch --no-tags linus master git checkout 8ca011ef4af48a7af7b15afd8a4a44039dd04cea # save the config file to linux build tree mkdir build_dir COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=arm SHELL=/bin/bash drivers/clk/bcm/ If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; All errors (new ones prefixed by >>): u64 rem; ^ 1 error generated. vim +/rem +942 drivers/clk/bcm/clk-bcm2835.c 41691b8862e2a3 Eric Anholt 2015-10-08 932 41691b8862e2a3 Eric Anholt 2015-10-08 933 static u32 bcm2835_clock_choose_div(struct clk_hw *hw, 41691b8862e2a3 Eric Anholt 2015-10-08 934 unsigned long rate, 8ca011ef4af48a Maxime Ripard 2021-09-22 935 unsigned long parent_rate) 41691b8862e2a3 Eric Anholt 2015-10-08 936 { 41691b8862e2a3 Eric Anholt 2015-10-08 937 struct bcm2835_clock *clock = bcm2835_clock_from_hw(hw); 41691b8862e2a3 Eric Anholt 2015-10-08 938 const struct bcm2835_clock_data *data = clock->data; 9c95b32ca09364 Remi Pommarel 2015-12-06 939 u32 unused_frac_mask = 9c95b32ca09364 Remi Pommarel 2015-12-06 940 GENMASK(CM_DIV_FRAC_BITS - data->frac_bits, 0) >> 1; 41691b8862e2a3 Eric Anholt 2015-10-08 941 u64 temp = (u64)parent_rate << CM_DIV_FRAC_BITS; 9c95b32ca09364 Remi Pommarel 2015-12-06 @942 u64 rem; 959ca92a3235fc Martin Sperl 2016-02-29 943 u32 div, mindiv, maxdiv; 41691b8862e2a3 Eric Anholt 2015-10-08 944 9c95b32ca09364 Remi Pommarel 2015-12-06 945 rem = do_div(temp, rate); 41691b8862e2a3 Eric Anholt 2015-10-08 946 div = temp; 41691b8862e2a3 Eric Anholt 2015-10-08 947 div &= ~unused_frac_mask; 41691b8862e2a3 Eric Anholt 2015-10-08 948 959ca92a3235fc Martin Sperl 2016-02-29 949 /* different clamping limits apply for a mash clock */ 959ca92a3235fc Martin Sperl 2016-02-29 950 if (data->is_mash_clock) { 959ca92a3235fc Martin Sperl 2016-02-29 951 /* clamp to min divider of 2 */ 959ca92a3235fc Martin Sperl 2016-02-29 952 mindiv = 2 << CM_DIV_FRAC_BITS; 959ca92a3235fc Martin Sperl 2016-02-29 953 /* clamp to the highest possible integer divider */ 959ca92a3235fc Martin Sperl 2016-02-29 954 maxdiv = (BIT(data->int_bits) - 1) << CM_DIV_FRAC_BITS; 959ca92a3235fc Martin Sperl 2016-02-29 955 } else { 997f16bd5d2e9b Martin Sperl 2016-02-29 956 /* clamp to min divider of 1 */ 959ca92a3235fc Martin Sperl 2016-02-29 957 mindiv = 1 << CM_DIV_FRAC_BITS; 997f16bd5d2e9b Martin Sperl 2016-02-29 958 /* clamp to the highest possible fractional divider */ 959ca92a3235fc Martin Sperl 2016-02-29 959 maxdiv = GENMASK(data->int_bits + CM_DIV_FRAC_BITS - 1, 959ca92a3235fc Martin Sperl 2016-02-29 960 CM_DIV_FRAC_BITS - data->frac_bits); 959ca92a3235fc Martin Sperl 2016-02-29 961 } 959ca92a3235fc Martin Sperl 2016-02-29 962 959ca92a3235fc Martin Sperl 2016-02-29 963 /* apply the clamping limits */ 959ca92a3235fc Martin Sperl 2016-02-29 964 div = max_t(u32, div, mindiv); 959ca92a3235fc Martin Sperl 2016-02-29 965 div = min_t(u32, div, maxdiv); 41691b8862e2a3 Eric Anholt 2015-10-08 966 41691b8862e2a3 Eric Anholt 2015-10-08 967 return div; 41691b8862e2a3 Eric Anholt 2015-10-08 968 } 41691b8862e2a3 Eric Anholt 2015-10-08 969 :::::: The code at line 942 was first introduced by commit :::::: 9c95b32ca09364e4687b72c4e17b78dc1c420026 clk: bcm2835: add a round up ability to the clock divisor :::::: TO: Remi Pommarel <repk(a)triplefau.lt&gt; :::::: CC: Michael Turquette <mturquette(a)baylibre.com&gt; --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org