Re: [linux-next:master 1467/1905] drivers/hwmon/nct6775-i2c.c:164:15: warning: cast to smaller integer type 'enum kinds' from 'const void *'

[Guenter Roeck <linux@roeck-us.net>]

On 11/20/23 08:40, Rob Herring wrote:
> On Sat, Nov 18, 2023 at 9:10 PM kernel test robot <lkp@intel.com> wrote:
>>
>> tree:   https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master
>> head:   eff99d8edbed7918317331ebd1e365d8e955d65e
>> commit: 0a7093e69c1eb508d699d6076013706b0c523597 [1467/1905] hwmon: nct6775-i2c: Use i2c_get_match_data()
>> config: x86_64-allmodconfig (https://download.01.org/0day-ci/archive/20231119/202311191205.EDRfQlJF-lkp@intel.com/config)
>> compiler: clang version 16.0.4 (https://github.com/llvm/llvm-project.git ae42196bc493ffe877a7e3dff8be32035dea4d07)
>> reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20231119/202311191205.EDRfQlJF-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@intel.com>
>> | Closes: https://lore.kernel.org/oe-kbuild-all/202311191205.EDRfQlJF-lkp@intel.com/
>>
>> All warnings (new ones prefixed by >>):
>>
>>>> drivers/hwmon/nct6775-i2c.c:164:15: warning: cast to smaller integer type 'enum kinds' from 'const void *' [-Wvoid-pointer-to-enum-cast]
>>             data->kind = (enum kinds)i2c_get_match_data(client);
>>                          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>>     1 warning generated.
> 
> I thought I had fixed all these...
> 
> However, there's also been discussion[1] to turn this warning off.
> 

This one is only seen with gcc-12+ (the exchange you cited is wrong in that
regard) and with clang. I agree that it is just noise - after all, there _is_
a type cast. Not worth arguing about, though, so I just changed it to use
a double type cast.

Guenter