Hi Baruch,

I love your patch! Perhaps something to improve:

[auto build test WARNING on pwm/for-next]
[also build test WARNING on robh/for-next v5.13-rc3 next-20210524]
[cannot apply to agross-msm/qcom/for-next]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Baruch-Siach/pwm-driver-for-qualcomm-ipq6018-pwm-block/20210524-182306
base:   https://git.kernel.org/pub/scm/linux/kernel/git/thierry.reding/linux-pwm.git for-next
config: arc-allyesconfig (attached as .config)
compiler: arceb-elf-gcc (GCC) 9.3.0
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
        # https://github.com/0day-ci/linux/commit/fd963192953e74575c0bba469b6a1ef769db9d33
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Baruch-Siach/pwm-driver-for-qualcomm-ipq6018-pwm-block/20210524-182306
        git checkout fd963192953e74575c0bba469b6a1ef769db9d33
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=arc 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All warnings (new ones prefixed by >>):

   drivers/pwm/pwm-ipq.c: In function 'ipq_pwm_apply':
>> drivers/pwm/pwm-ipq.c:125:34: warning: integer overflow in expression of type 'long int' results in '-727379968' [-Woverflow]
     125 |  fin_ps = div64_u64(NSEC_PER_SEC * 1000, rate);
         |                                  ^


vim +125 drivers/pwm/pwm-ipq.c

   103	
   104	static int ipq_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
   105				 const struct pwm_state *state)
   106	{
   107		struct ipq_pwm_chip *ipq_chip = to_ipq_pwm_chip(chip);
   108		unsigned long freq;
   109		int pre_div, close_pre_div, close_pwm_div;
   110		int pwm_div;
   111		long long diff;
   112		unsigned long rate = clk_get_rate(ipq_chip->clk);
   113		unsigned long min_diff = rate;
   114		uint64_t fin_ps;
   115		u64 period_ns, duty_ns;
   116	
   117		if (state->period < MIN_PERIOD_NS)
   118			return -ERANGE;
   119	
   120		period_ns = min_t(u64, state->period, MAX_PERIOD_NS);
   121		duty_ns = min_t(u64, state->duty_cycle, period_ns);
   122	
   123		/* freq in Hz for period in nano second*/
   124		freq = NSEC_PER_SEC / period_ns;
 > 125		fin_ps = div64_u64(NSEC_PER_SEC * 1000, rate);
   126		close_pre_div = MAX_PWM_CFG;
   127		close_pwm_div = MAX_PWM_CFG;
   128	
   129		for (pre_div = 0; pre_div <= MAX_PWM_CFG; pre_div++) {
   130			pwm_div = DIV64_U64_ROUND_CLOSEST(period_ns * 1000,
   131							  fin_ps * (pre_div + 1));
   132			pwm_div--;
   133			if (pwm_div < 0 || pwm_div > MAX_PWM_CFG)
   134				continue;
   135	
   136			diff = ((uint64_t)freq * (pre_div + 1) * (pwm_div + 1))
   137				- (uint64_t)rate;
   138	
   139			if (diff < 0) /* period larger than requested */
   140				continue;
   141			if (diff == 0) { /* bingo */
   142				close_pre_div = pre_div;
   143				close_pwm_div = pwm_div;
   144				break;
   145			}
   146			if (diff < min_diff) {
   147				min_diff = diff;
   148				close_pre_div = pre_div;
   149				close_pwm_div = pwm_div;
   150			}
   151		}
   152	
   153		/* config divider values for the closest possible frequency */
   154		config_div_and_duty(pwm, close_pre_div, close_pwm_div,
   155				    period_ns, duty_ns);
   156		if (state->enabled)
   157			ipq_pwm_enable(pwm);
   158		else
   159			ipq_pwm_disable(pwm);
   160	
   161		return 0;
   162	}
   163	

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org