Re: [groeck-staging:hwmon-next 77/79] drivers/hwmon/tps23861.c:159:19: sparse: sparse: cast to restricted __le16

"Alex G." <mr.nuke.me@xxxxxxxxx> · Thu, 21 Jul 2022 17:03:02 -0500

Hi Guenter,

On 7/21/22 05:41, kernel test robot wrote:
tree:   https://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging.git hwmon-next
head:   5668b5e6cffd975632ee6c32802d7d877b98e9a4
commit: 7024d59f146ea99d95b7f238e9991f32f31496b0 [77/79] hwmon: (tps23861) fix byte order in current and voltage registers
config: alpha-randconfig-s053-20220720 (https://download.01.org/0day-ci/archive/20220721/202207211843.3aLaNmh9-lkp@xxxxxxxxx/config)
compiler: alpha-linux-gcc (GCC) 12.1.0
reproduce:
         wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
         chmod +x ~/bin/make.cross
         # apt-get install sparse
         # sparse version: v0.6.4-39-gce1a6720-dirty
         # https://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging.git/commit/?id=7024d59f146ea99d95b7f238e9991f32f31496b0
         git remote add groeck-staging https://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging.git
         git fetch --no-tags groeck-staging hwmon-next
         git checkout 7024d59f146ea99d95b7f238e9991f32f31496b0
         # save the config file
         mkdir build_dir && cp config build_dir/.config
         COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' O=build_dir ARCH=alpha SHELL=/bin/bash drivers/hwmon/

If you fix the issue, kindly add following tag where applicable
Reported-by: kernel test robot <lkp@xxxxxxxxx>

sparse warnings: (new ones prefixed by >>)
drivers/hwmon/tps23861.c:159:19: sparse: sparse: cast to restricted __le16
    drivers/hwmon/tps23861.c:184:19: sparse: sparse: cast to restricted __le16

I'm sorry about this. These warnings caught me by surprise. I checked 
that changing the type from "uint16_t" to "__le16" silences sparse. It
feels like a false positive. Should I worry about this?

Alex

vim +159 drivers/hwmon/tps23861.c

    139	
    140	static int tps23861_read_voltage(struct tps23861_data *data, int channel,
    141					 long *val)
    142	{
    143		uint16_t regval;
    144		long raw_val;
    145		int err;
    146	
    147		if (channel < TPS23861_NUM_PORTS) {
    148			err = regmap_bulk_read(data->regmap,
    149					       PORT_1_VOLTAGE_LSB + channel * PORT_N_VOLTAGE_LSB_OFFSET,
    150					       &regval, 2);
    151		} else {
    152			err = regmap_bulk_read(data->regmap,
    153					       INPUT_VOLTAGE_LSB,
    154					       &regval, 2);
    155		}
    156		if (err < 0)
    157			return err;
    158	
  > 159		raw_val = le16_to_cpu(regval);
    160		*val = (FIELD_GET(VOLTAGE_CURRENT_MASK, raw_val) * VOLTAGE_LSB) / 1000;
    161	
    162		return 0;
    163	}
    164	