On 5/7/19 2:06 PM, Guenter Roeck wrote:
> On Tue, May 07, 2019 at 12:35:02PM -0700, Florian Fainelli wrote:
>> Provide a simple macro that can return the value of 10 raised to a
>> positive integer. We are going to use this in order to scale units from
>> firmware to HWMON.
>>
>> Signed-off-by: Florian Fainelli <f.fainelli@xxxxxxxxx>
>> ---
>> include/linux/kernel.h | 11 +++++++++++
>> 1 file changed, 11 insertions(+)
>>
>> diff --git a/include/linux/kernel.h b/include/linux/kernel.h
>> index 2d14e21c16c0..62fc8bd84bc9 100644
>> --- a/include/linux/kernel.h
>> +++ b/include/linux/kernel.h
>> @@ -294,6 +294,17 @@ static inline u32 reciprocal_scale(u32 val, u32 ep_ro)
>> return (u32)(((u64) val * ep_ro) >> 32);
>> }
>>
>> +/* Return in f the value of 10 raise to the power x */
>> +#define __pow10(x, f)( \
>> +{ \
>> + typeof(x) __x = abs(x); \
>> + f = 1; \
>> + while (__x--) \
>> + f *= 10; \
>> + f; \
>> +} \
>> +)
>
> Kind of unusual. I would have expected to use this like
> f = __pow10(x);
> ie without having to provide f as parameter. That would be much less
> confusing. I assume this is to make the result type independent, but
> I am not sure if that is worth the trouble.
Correct, that was the intent here.
>
> Are there users outside the hwmon code ? If not, it might be simpler
> to keep it there for now.
There appears to be a few outside actually:
drivers/acpi/sbs.c::battery_scale
drivers/iio/common/hid-sensors/hid-sensor-attributes.c::pow_10
There could be others but those two came out as obvious candidates.
Would you be okay with a local pow10 function within scmi-hwmon.c and a
subsequent patch series providing a common function?
--
Florian
