On 11/20/23 15:00, Andy Shevchenko wrote:
> On Thu, Nov 16, 2023 at 03:46:55PM +0200, mitrutzceclan wrote:
>> +struct ad7173_channel_config {
>> + bool live;
>> + u8 cfg_slot;
>> + /* Following fields are used to compare equality. Bipolar must be first */
>> + bool bipolar;
>> + bool input_buf;
>> + u8 odr;
>> + u8 ref_sel;
>
> If you group better by types, it might save a few bytes on the architectures /
> compilers where bool != byte.
>
Grouping by type will result in not being able to use memcmp() for
comparing configs. But then there is the issue that I was under the
assumption that bool=byte. If that is not the case, the config equality
check might be comparing padding bytes.
In this case what do you suggest:
- using the packed attribute
- using only u8
- drop memcmp, manually compare fields
...
>> + cmp_size = sizeof(*cfg) - offset;
>
> sizeof_field() from the above mentioned header?
This computes the size of multiple fields, following cfg_slot. Better to
group the fields that need to be compared into another struct then use
sizeof_field()?
...
>
>> + return vref / (MICRO/MILLI);
>
> What does the denominator mean and why you can't simply use MILL?
>
Original vref values are in micro, I considered that it was adequate to
represent the conversion from MICRO to MILLI as a fraction.
>> + *val = st->info->sinc5_data_rates[reg] / (MICRO/MILLI);
>> + *val2 = (st->info->sinc5_data_rates[reg] % MILLI) * (MICRO/MILLI);
>
> Same Q about denominator.
>
Here, a misunderstanding on my part of a suggestion from Jonathan in V2,
will be removed.
