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From: Chen-Yu Tsai <wens@csie.org>
Date: Sun, 7 Jan 2024 13:37:30 +0800
Message-ID: <CAGb2v64zGvceVXy_F7pVTrFYY7-eLQktoWZB4Xcb1MQtFu=1Ww@mail.gmail.com>
Subject: Re: drivers/iio/adc/axp20x_adc.c:572:26: sparse: sparse: dubious: x & !y
To: kernel test robot <lkp@intel.com>
Cc: Aidan MacDonald <aidanmacdonald.0x0@gmail.com>, oe-kbuild-all@lists.linux.dev, 
	linux-kernel@vger.kernel.org, Jonathan Cameron <Jonathan.Cameron@huawei.com>, 
	Andy Shevchenko <andy.shevchenko@gmail.com>
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On Sun, Jan 7, 2024 at 9:30=E2=80=AFAM kernel test robot <lkp@intel.com> wr=
ote:
>
> tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.gi=
t master
> head:   52b1853b080a082ec3749c3a9577f6c71b1d4a90
> commit: 8957e5344353e9cd3f6b1e3004942e35449fa0e8 iio: adc: axp20x_adc: Mi=
nor code cleanups
> date:   10 months ago
> config: x86_64-randconfig-121-20240106 (https://download.01.org/0day-ci/a=
rchive/20240107/202401070901.68H00NFa-lkp@intel.com/config)
> compiler: ClangBuiltLinux clang version 17.0.6 (https://github.com/llvm/l=
lvm-project 6009708b4367171ccdbf4b5905cb6a803753fe18)
> reproduce (this is a W=3D1 build): (https://download.01.org/0day-ci/archi=
ve/20240107/202401070901.68H00NFa-lkp@intel.com/reproduce)
>
> If you fix the issue in a separate patch/commit (i.e. not just a new vers=
ion 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/202401070901.68H00NFa-lkp=
@intel.com/
>
> sparse warnings: (new ones prefixed by >>)
> >> drivers/iio/adc/axp20x_adc.c:572:26: sparse: sparse: dubious: x & !y
>    drivers/iio/adc/axp20x_adc.c:577:26: sparse: sparse: dubious: x & !y

This looks like a false positive. The code is doing exactly what we want:
val =3D val ? 1 : 0, but in a shorter format.

ChenYu

>
> vim +572 drivers/iio/adc/axp20x_adc.c
>
>    551
>    552  static int axp20x_write_raw(struct iio_dev *indio_dev,
>    553                              struct iio_chan_spec const *chan, int=
 val, int val2,
>    554                              long mask)
>    555  {
>    556          struct axp20x_adc_iio *info =3D iio_priv(indio_dev);
>    557          unsigned int regmask, regval;
>    558
>    559          /*
>    560           * The AXP20X PMIC allows the user to choose between 0V a=
nd 0.7V offsets
>    561           * for (independently) GPIO0 and GPIO1 when in ADC mode.
>    562           */
>    563          if (mask !=3D IIO_CHAN_INFO_OFFSET)
>    564                  return -EINVAL;
>    565
>    566          if (val !=3D 0 && val !=3D 700000)
>    567                  return -EINVAL;
>    568
>    569          switch (chan->channel) {
>    570          case AXP20X_GPIO0_V:
>    571                  regmask =3D AXP20X_GPIO10_IN_RANGE_GPIO0;
>  > 572                  regval =3D FIELD_PREP(AXP20X_GPIO10_IN_RANGE_GPIO=
0, !!val);
>    573                  break;
>    574
>    575          case AXP20X_GPIO1_V:
>    576                  regmask =3D AXP20X_GPIO10_IN_RANGE_GPIO1;
>    577                  regval =3D FIELD_PREP(AXP20X_GPIO10_IN_RANGE_GPIO=
1, !!val);
>    578                  break;
>    579
>    580          default:
>    581                  return -EINVAL;
>    582          }
>    583
>    584          return regmap_update_bits(info->regmap, AXP20X_GPIO10_IN_=
RANGE, regmask, regval);
>    585  }
>    586
>
> --
> 0-DAY CI Kernel Test Service
> https://github.com/intel/lkp-tests/wiki