[PATCH v5] drm/i915/hwmon: expose fan speed

[kernel test robot]

Hi Raag,

kernel test robot noticed the following build errors:

[auto build test ERROR on groeck-staging/hwmon-next]
[also build test ERROR on linus/master v6.11-rc3 next-20240812]
[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/Raag-Jadav/drm-i915-hwmon-expose-fan-speed/20240812-161645
base:   https://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging.git hwmon-next
patch link:    https://lore.kernel.org/r/20240812081538.1457396-1-raag.jadav%40intel.com
patch subject: [PATCH v5] drm/i915/hwmon: expose fan speed
config: i386-randconfig-012-20240813 (https://download.01.org/0day-ci/archive/20240813/202408130500.SgCVoR2D-lkp@intel.com/config)
compiler: gcc-12 (Debian 12.2.0-14) 12.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240813/202408130500.SgCVoR2D-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 at intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202408130500.SgCVoR2D-lkp@intel.com/

All errors (new ones prefixed by >>):

   ld: drivers/gpu/drm/i915/i915_hwmon.o: in function `hwm_fan_read':
>> drivers/gpu/drm/i915/i915_hwmon.c:675: undefined reference to `__udivdi3'


vim +675 drivers/gpu/drm/i915/i915_hwmon.c

   633	
   634	static int
   635	hwm_fan_read(struct hwm_drvdata *ddat, u32 attr, long *val)
   636	{
   637		struct i915_hwmon *hwmon = ddat->hwmon;
   638		struct hwm_fan_info *fi = &ddat->fi;
   639		u64 rotations, time_now, time;
   640		intel_wakeref_t wakeref;
   641		u32 reg_val, pulses;
   642		int ret = 0;
   643	
   644		if (attr != hwmon_fan_input)
   645			return -EOPNOTSUPP;
   646	
   647		wakeref = intel_runtime_pm_get(ddat->uncore->rpm);
   648		mutex_lock(&hwmon->hwmon_lock);
   649	
   650		reg_val = intel_uncore_read(ddat->uncore, hwmon->rg.fan_speed);
   651		time_now = get_jiffies_64();
   652	
   653		/* Handle HW register overflow */
   654		if (reg_val >= fi->reg_val_prev)
   655			pulses = reg_val - fi->reg_val_prev;
   656		else
   657			pulses = UINT_MAX - fi->reg_val_prev + reg_val;
   658	
   659		/*
   660		 * HW register value is accumulated count of pulses from
   661		 * PWM fan with the scale of 2 pulses per rotation.
   662		 */
   663		rotations = pulses / 2;
   664	
   665		time = jiffies_delta_to_msecs(time_now - fi->time_prev);
   666		if (unlikely(!time)) {
   667			ret = -EAGAIN;
   668			goto exit;
   669		}
   670	
   671		/*
   672		 * Convert to minutes for calculating RPM.
   673		 * RPM = number of rotations * msecs per minute / time in msecs
   674		 */
 > 675		*val = DIV_ROUND_UP(rotations * (MSEC_PER_SEC * 60), time);
   676	
   677		fi->reg_val_prev = reg_val;
   678		fi->time_prev = time_now;
   679	exit:
   680		mutex_unlock(&hwmon->hwmon_lock);
   681		intel_runtime_pm_put(ddat->uncore->rpm, wakeref);
   682		return ret;
   683	}
   684	

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