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 <[email protected]> >> --- >> 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
