Re: [PATCH v3 2/2] pwm: sifive: change the PWM controlled LED algorithm

[kernel test robot <lkp@intel.com>]

Hi Nylon,

kernel test robot noticed the following build warnings:

[auto build test WARNING on robh/for-next]
[also build test WARNING on thierry-reding-pwm/for-next rockchip/for-next linus/master v6.3-rc7 next-20230419]
[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#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Nylon-Chen/riscv-dts-sifive-unleashed-unmatched-Remove-PWM-controlled-LED-s-active-low-properties/20230420-173619
base:   https://git.kernel.org/pub/scm/linux/kernel/git/robh/linux.git for-next
patch link:    https://lore.kernel.org/r/20230420093457.18936-3-nylon.chen%40sifive.com
patch subject: [PATCH v3 2/2] pwm: sifive: change the PWM controlled LED algorithm
config: m68k-allyesconfig (https://download.01.org/0day-ci/archive/20230420/202304202141.JYCKBVOQ-lkp@intel.com/config)
compiler: m68k-linux-gcc (GCC) 12.1.0
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/intel-lab-lkp/linux/commit/f2d706bf61190a45a8f90f1f455bc943d4ac7b6e
        git remote add linux-review https://github.com/intel-lab-lkp/linux
        git fetch --no-tags linux-review Nylon-Chen/riscv-dts-sifive-unleashed-unmatched-Remove-PWM-controlled-LED-s-active-low-properties/20230420-173619
        git checkout f2d706bf61190a45a8f90f1f455bc943d4ac7b6e
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross W=1 O=build_dir ARCH=m68k olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross W=1 O=build_dir ARCH=m68k SHELL=/bin/bash drivers/

If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <lkp@intel.com>
| Link: https://lore.kernel.org/oe-kbuild-all/202304202141.JYCKBVOQ-lkp@intel.com/

All warnings (new ones prefixed by >>):

   In file included from include/linux/kernel.h:26,
                    from include/linux/clk.h:13,
                    from drivers/pwm/pwm-sifive.c:14:
   drivers/pwm/pwm-sifive.c: In function 'pwm_sifive_apply':
   include/linux/minmax.h:20:35: warning: comparison of distinct pointer types lacks a cast
      20 |         (!!(sizeof((typeof(x) *)1 == (typeof(y) *)1)))
         |                                   ^~
   include/linux/minmax.h:26:18: note: in expansion of macro '__typecheck'
      26 |                 (__typecheck(x, y) && __no_side_effects(x, y))
         |                  ^~~~~~~~~~~
   include/linux/minmax.h:36:31: note: in expansion of macro '__safe_cmp'
      36 |         __builtin_choose_expr(__safe_cmp(x, y), \
         |                               ^~~~~~~~~~
   include/linux/minmax.h:74:25: note: in expansion of macro '__careful_cmp'
      74 | #define max(x, y)       __careful_cmp(x, y, >)
         |                         ^~~~~~~~~~~~~
   drivers/pwm/pwm-sifive.c:157:18: note: in expansion of macro 'max'
     157 |         period = max(state->period, ddata->approx_period);
         |                  ^~~
>> drivers/pwm/pwm-sifive.c:135:34: warning: variable 'period' set but not used [-Wunused-but-set-variable]
     135 |         unsigned int duty_cycle, period;
         |                                  ^~~~~~


vim +/period +135 drivers/pwm/pwm-sifive.c

   129	
   130	static int pwm_sifive_apply(struct pwm_chip *chip, struct pwm_device *pwm,
   131				    const struct pwm_state *state)
   132	{
   133		struct pwm_sifive_ddata *ddata = pwm_sifive_chip_to_ddata(chip);
   134		struct pwm_state cur_state;
 > 135		unsigned int duty_cycle, period;
   136		unsigned long long num;
   137		bool enabled;
   138		int ret = 0;
   139		u32 frac;
   140	
   141		if (state->polarity != PWM_POLARITY_NORMAL && state->polarity != PWM_POLARITY_INVERSED)
   142			return -EINVAL;
   143	
   144		cur_state = pwm->state;
   145		enabled = cur_state.enabled;
   146	
   147		duty_cycle = state->duty_cycle;
   148		if (!state->enabled)
   149			duty_cycle = 0;
   150	
   151		/*
   152		 * The problem of output producing mixed setting as mentioned at top,
   153		 * occurs here. To minimize the window for this problem, we are
   154		 * calculating the register values first and then writing them
   155		 * consecutively
   156		 */
   157		period = max(state->period, ddata->approx_period);
   158		num = (u64)duty_cycle * (1U << PWM_SIFIVE_CMPWIDTH);
   159		frac = DIV64_U64_ROUND_CLOSEST(num, state->period);
   160		frac = min(frac, (1U << PWM_SIFIVE_CMPWIDTH) - 1);
   161		/* The hardware cannot generate a 100% duty cycle */
   162		frac = (1U << PWM_SIFIVE_CMPWIDTH) - 1 - frac;
   163	
   164	
   165		mutex_lock(&ddata->lock);
   166		if (state->period != ddata->approx_period) {
   167			/*
   168			 * Don't let a 2nd user change the period underneath the 1st user.
   169			 * However if ddate->approx_period == 0 this is the first time we set
   170			 * any period, so let whoever gets here first set the period so other
   171			 * users who agree on the period won't fail.
   172			 */
   173			if (ddata->user_count != 1 && ddata->approx_period) {
   174				mutex_unlock(&ddata->lock);
   175				return -EBUSY;
   176			}
   177			ddata->approx_period = state->period;
   178			pwm_sifive_update_clock(ddata, clk_get_rate(ddata->clk));
   179		}
   180		mutex_unlock(&ddata->lock);
   181	
   182		/*
   183		 * If the PWM is enabled the clk is already on. So only enable it
   184		 * conditionally to have it on exactly once afterwards independent of
   185		 * the PWM state.
   186		 */
   187		if (!enabled) {
   188			ret = clk_enable(ddata->clk);
   189			if (ret) {
   190				dev_err(ddata->chip.dev, "Enable clk failed\n");
   191				return ret;
   192			}
   193		}
   194	
   195		writel(frac, ddata->regs + PWM_SIFIVE_PWMCMP(pwm->hwpwm));
   196	
   197		if (!state->enabled)
   198			clk_disable(ddata->clk);
   199	
   200		return 0;
   201	}
   202	

-- 
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https://github.com/intel/lkp-tests