Re: [PATCH v5 4/4] iio: cdc: add Texas Instruments FDC1004 driver

[kernel test robot]

Hi Victor,

kernel test robot noticed the following build warnings:

[auto build test WARNING on jic23-iio/togreg]
[also build test WARNING on linus/master v7.4-rc1 next-20261105]
[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/Victor-Chernyakin/iio-prepare-iio_format_value-to-handle-higher-precision-IIO_VAL_DECIMAL64_-formats/20261106-094026
base:   https://git.kernel.org/pub/scm/linux/kernel/git/jic23/iio.git togreg
patch link:    https://lore.kernel.org/r/SN1PR12MB2528BA7C696815089DCAD02FA5762%40SN1PR12MB2528.namprd12.prod.outlook.com
patch subject: [PATCH v5 4/4] iio: cdc: add Texas Instruments FDC1004 driver
config: nios2-randconfig-1000-20261107 (https://download.01.org/0day-ci/archive/20261107/202611070503.6fdgeWCZ-lkp@xxxxxxxxx/config)
compiler: nios2-linux-gcc (GCC) 8.5.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20261107/202611070503.6fdgeWCZ-lkp@xxxxxxxxx/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@xxxxxxxxx>
| Closes: https://lore.kernel.org/oe-kbuild-all/202611070503.6fdgeWCZ-lkp@xxxxxxxxx/

All warnings (new ones prefixed by >>):

>> drivers/iio/cdc/fdc1004.c:67:10: warning: integer overflow in expression of type 'long int' results in '-1246822400' [-Woverflow]
     -0x8000 * 488281250L, /* min */
             ^
   drivers/iio/cdc/fdc1004.c:69:10: warning: integer overflow in expression of type 'long int' results in '758541150' [-Woverflow]
     +0x7FFF * 488281250L, /* max */
             ^


vim +67 drivers/iio/cdc/fdc1004.c

    59	
    60	/*
    61	 * OFFSET_CAL_CINn: 16 bits, signed. Format: IIO_VAL_DECIMAL64_FEMTO.
    62	 * 1 step = 1/(2^11) pF = 1/(1000 * 2^11) nF = 0.000000488281250 nF.
    63	 * Negative values are used to cancel out any parasitic capacitance
    64	 * of the sensor's external circuitry.
    65	 */
    66	static const s64 fdc1004_calibbias[] = {
  > 67		-0x8000 * 488281250L, /* min */
    68		+0x0001 * 488281250L, /* step */
    69		+0x7FFF * 488281250L, /* max */
    70	};
    71	

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