Re: [PATCH] hwmon: max31790: support to config PWM as TACH

kernel test robot
2023-09-08T18:42:00Z

Hi Delphine,

kernel test robot noticed the following build warnings:

[auto build test WARNING on groeck-staging/hwmon-next]
[also build test WARNING on linus/master v6.5 next-20230908]
[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/Delphine-CC-Chiu/hwmon-max31790-support-to-config-PWM-as-TACH/20230906-165344
base: https://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging.git hwmon-next
patch link: https://lore.kernel.org/r/20230906084837.3043030-3-Delphine_CC_Chiu%40wiwynn.com
patch subject: [PATCH] hwmon: max31790: support to config PWM as TACH
config: x86_64-randconfig-161-20230907 (https://download.01.org/0day-ci/archive/20230909/202309090228.2bSFmAO8-lkp@intel.com/config)
compiler: gcc-12 (Debian 12.2.0-14) 12.2.0
reproduce: (https://download.01.org/0day-ci/archive/20230909/202309090228.2bSFmAO8-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202309090228.2bSFmAO8-lkp@intel.com/

smatch warnings:
drivers/hwmon/max31790.c:511 max31790_config_pwm_as_tach() warn: unsigned 'fan_config' is never less than zero.

vim +/fan_config +511 drivers/hwmon/max31790.c

482
483 static int max31790_config_pwm_as_tach(struct device *dev,
484 struct i2c_client *client)
485 {
486 struct device_node *np = dev->of_node;
487 int i, ret = 0, size, channel;
488 u8 pwm_index[NR_CHANNEL] = { 0 };
489 u8 fan_config;
490
491 size = of_property_count_u8_elems(np, "pwm-as-tach");
492
493 if ((size > 0) && (size <= NR_CHANNEL)) {
494 ret = of_property_read_u8_array(np, "pwm-as-tach", pwm_index,
495 size);
496 if (ret) {
497 dev_err(dev,
498 "Property 'pwm-as-tach' cannot be read.\n");
499 return ret;
500 }
501
502 for (i = 0; i < size; i++) {
503 if ((pwm_index[i] == 0) ||
504 (pwm_index[i] > NR_CHANNEL)) {
505 continue;
506 }
507
508 channel = pwm_index[i] - 1;
509 fan_config = i2c_smbus_read_byte_data(
510 client, MAX31790_REG_FAN_CONFIG(channel));
> 511 if (fan_config < 0) {
512 dev_err(dev,
513 "Read fan config for channel %d failed.\n",
514 channel);
515 return fan_config;
516 }
517
518 fan_config |= (MAX31790_FAN_CFG_CTRL_MON |
519 MAX31790_FAN_CFG_TACH_INPUT);
520 i2c_smbus_write_byte_data(
521 client, MAX31790_REG_FAN_CONFIG(channel),
522 fan_config);
523 }
524 }
525
526 return 0;
527 }
528

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