Re: [PATCH] hwmon: (pmbus) Use 64bit math for DIRECT format values

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

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Hi Robert,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on hwmon/hwmon-next]
[also build test WARNING on v4.14 next-20171124]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Robert-Lippert/hwmon-pmbus-Use-64bit-math-for-DIRECT-format-values/20171126-031040
base:   https://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging.git hwmon-next
config: xtensa-allmodconfig (attached as .config)
compiler: xtensa-linux-gcc (GCC) 4.9.0
reproduce:
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # save the attached .config to linux build tree
        make.cross ARCH=xtensa 

All warnings (new ones prefixed by >>):

   In file included from ./arch/xtensa/include/generated/asm/div64.h:1:0,
                    from include/linux/kernel.h:173,
                    from include/linux/list.h:9,
                    from include/linux/wait.h:7,
                    from include/linux/wait_bit.h:8,
                    from include/linux/fs.h:6,
                    from include/linux/debugfs.h:18,
                    from drivers/hwmon//pmbus/pmbus_core.c:22:
   drivers/hwmon//pmbus/pmbus_core.c: In function 'pmbus_reg2data_direct':
   include/asm-generic/div64.h:222:28: warning: comparison of distinct pointer types lacks a cast
     (void)(((typeof((n)) *)0) == ((uint64_t *)0)); \
                               ^
>> drivers/hwmon//pmbus/pmbus_core.c:531:3: note: in expansion of macro 'do_div'
      do_div(val, 10);
      ^
   include/asm-generic/div64.h:222:28: warning: comparison of distinct pointer types lacks a cast
     (void)(((typeof((n)) *)0) == ((uint64_t *)0)); \
                               ^
   drivers/hwmon//pmbus/pmbus_core.c:536:2: note: in expansion of macro 'do_div'
     do_div(val, m);
     ^
   drivers/hwmon//pmbus/pmbus_core.c: In function 'pmbus_data2reg_direct':
   include/asm-generic/div64.h:222:28: warning: comparison of distinct pointer types lacks a cast
     (void)(((typeof((n)) *)0) == ((uint64_t *)0)); \
                               ^
   drivers/hwmon//pmbus/pmbus_core.c:686:3: note: in expansion of macro 'do_div'
      do_div(val64, 10);
      ^

vim +/do_div +531 drivers/hwmon//pmbus/pmbus_core.c

   494	
   495	/*
   496	 * Convert direct sensor values to milli- or micro-units
   497	 * depending on sensor type.
   498	 */
   499	static long pmbus_reg2data_direct(struct pmbus_data *data,
   500					  struct pmbus_sensor *sensor)
   501	{
   502		s64 val = (s16) sensor->data;
   503		s64 m, b, R;
   504	
   505		m = data->info->m[sensor->class];
   506		b = data->info->b[sensor->class];
   507		R = data->info->R[sensor->class];
   508	
   509		if (m == 0)
   510			return 0;
   511	
   512		/* X = 1/m * (Y * 10^-R - b) */
   513		R = -R;
   514		/* scale result to milli-units for everything but fans */
   515		if (sensor->class != PSC_FAN) {
   516			R += 3;
   517			b *= 1000;
   518		}
   519	
   520		/* scale result to micro-units for power sensors */
   521		if (sensor->class == PSC_POWER) {
   522			R += 3;
   523			b *= 1000;
   524		}
   525	
   526		while (R > 0) {
   527			val *= 10;
   528			R--;
   529		}
   530		while (R < 0) {
 > 531			do_div(val, 10);
   532			R++;
   533		}
   534	
   535		val = val - b;
   536		do_div(val, m);
   537		return val;
   538	}
   539	

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0-DAY kernel test infrastructure                Open Source Technology Center
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