[PATCH 1/3] mmc: Convert hs400_tuning flag from u8 to bool

[Marek Vasut]

On 2/20/24 3:41 PM, Paul Barker wrote:
> On 20/02/2024 11:27, Marek Vasut wrote:
>> On 2/20/24 11:57, Paul Barker wrote:
>>> On 20/02/2024 08:37, Marek Vasut wrote:
>>>> This hs400_tuning is a flag, make it bool. No functional change.
>>>> This will be useful in the following patch, which adds another
>>>> more generic flag, where the compiler can better use the space
>>>> now reserved for the u8 to store more flags in it.
>>>
>>> The minimum size for a bool is one byte so there likely won't be any
>>> improvement in struct size from using bool instead of u8 for
>>> `hs400_tuning` here and `tuning` added in the next patch. I still think
>>> it's a good change to make though, bool is the right type for an on/off
>>> flag.
>>
>> The compiler does not do boolean packing in structures ?
> 
> The compiler will only pack booleans if you explicitly say that only
> one bit of memory is needed, e.g.:
> 
>      bool tuning:1;
>      bool hs400_tuning:1;
> 
> Otherwise the assumption is that you may wish to take the address of
> each field and so each one must have a distinct address in memory.

Fixed in V2, thanks !