[jic23-iio:testing 9/10] drivers/iio/adc/palmas_gpadc.c:753:7: warning: variable 'old' is used uninitialized whenever 'if' condition is true

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

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/jic23/iio.git testing
head:   32f442dba193b5682bd1e9784b0ea42893c6e966
commit: 78441f504e3991b3f33b48de6fc8ed3cba7a40a7 [9/10] iio: adc: palmas: add support for iio threshold events
config: i386-randconfig-a002-20230410 (https://download.01.org/0day-ci/archive/20230413/202304130711.Eueav3k7-lkp@intel.com/config)
compiler: clang version 14.0.6 (https://github.com/llvm/llvm-project f28c006a5895fc0e329fe15fead81e37457cb1d1)
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://git.kernel.org/pub/scm/linux/kernel/git/jic23/iio.git/commit/?id=78441f504e3991b3f33b48de6fc8ed3cba7a40a7
        git remote add jic23-iio https://git.kernel.org/pub/scm/linux/kernel/git/jic23/iio.git
        git fetch --no-tags jic23-iio testing
        git checkout 78441f504e3991b3f33b48de6fc8ed3cba7a40a7
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=i386 olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=i386 SHELL=/bin/bash drivers/iio/adc/

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/202304130711.Eueav3k7-lkp@intel.com/

All warnings (new ones prefixed by >>):

>> drivers/iio/adc/palmas_gpadc.c:753:7: warning: variable 'old' is used uninitialized whenever 'if' condition is true [-Wsometimes-uninitialized]
                   if (val < 0 || val > 0xFFF) {
                       ^~~~~~~~~~~~~~~~~~~~~~
   drivers/iio/adc/palmas_gpadc.c:772:13: note: uninitialized use occurs here
           if (val != old && palmas_gpadc_get_event(adc, adc_chan, dir))
                      ^~~
   drivers/iio/adc/palmas_gpadc.c:753:3: note: remove the 'if' if its condition is always false
                   if (val < 0 || val > 0xFFF) {
                   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>> drivers/iio/adc/palmas_gpadc.c:753:7: warning: variable 'old' is used uninitialized whenever '||' condition is true [-Wsometimes-uninitialized]
                   if (val < 0 || val > 0xFFF) {
                       ^~~~~~~
   drivers/iio/adc/palmas_gpadc.c:772:13: note: uninitialized use occurs here
           if (val != old && palmas_gpadc_get_event(adc, adc_chan, dir))
                      ^~~
   drivers/iio/adc/palmas_gpadc.c:753:7: note: remove the '||' if its condition is always false
                   if (val < 0 || val > 0xFFF) {
                       ^~~~~~~~~~
   drivers/iio/adc/palmas_gpadc.c:744:9: note: initialize the variable 'old' to silence this warning
           int old;
                  ^
                   = 0
   2 warnings generated.


vim +753 drivers/iio/adc/palmas_gpadc.c

   734	
   735	static int palmas_gpadc_write_event_value(struct iio_dev *indio_dev,
   736						  const struct iio_chan_spec *chan,
   737						  enum iio_event_type type,
   738						  enum iio_event_direction dir,
   739						  enum iio_event_info info,
   740						  int val, int val2)
   741	{
   742		struct palmas_gpadc *adc = iio_priv(indio_dev);
   743		int adc_chan = chan->channel;
   744		int old;
   745		int ret;
   746	
   747		if (adc_chan > PALMAS_ADC_CH_MAX || type != IIO_EV_TYPE_THRESH)
   748			return -EINVAL;
   749	
   750		mutex_lock(&adc->lock);
   751		switch (info) {
   752		case IIO_EV_INFO_VALUE:
 > 753			if (val < 0 || val > 0xFFF) {
   754				ret = -EINVAL;
   755				break;
   756			}
   757			if (dir == IIO_EV_DIR_RISING) {
   758				old = adc->thresholds[adc_chan].high;
   759				adc->thresholds[adc_chan].high = val;
   760			}
   761			else {
   762				old = adc->thresholds[adc_chan].low;
   763				adc->thresholds[adc_chan].low = val;
   764			}
   765			ret = 0;
   766			break;
   767		default:
   768			ret = -EINVAL;
   769			goto out_unlock;
   770		}
   771	
   772		if (val != old && palmas_gpadc_get_event(adc, adc_chan, dir))
   773			ret = palmas_gpadc_reconfigure_event_channels(adc);
   774	
   775	out_unlock:
   776		mutex_unlock(&adc->lock);
   777	
   778		return ret;
   779	}
   780	

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