On Mon, Jun 25, 2018 at 6:22 PM, Akinobu Mita <akinobu.mita@xxxxxxxxx> wrote:
> The ADXL345 provides selectable output data rate. This adds the iio
> channel information for the sampling frequency with that feature.
> +#define ADXL345_BW_RATE GENMASK(3, 0)
> +#define ADXL345_BASE_RATE_NANO_HZ 97656250LL
> + samp_freq_nhz = ADXL345_BASE_RATE_NANO_HZ <<
> + (regval & ADXL345_BW_RATE);
> + *val = div_s64_rem(samp_freq_nhz, 1000000000, val2);
Yep, looks cool!
> + for (i = 0; i <= ADXL345_BW_RATE; i++) {
> + int nhz;
> + int hz;
> +
> + hz = div_s64_rem(ADXL345_BASE_RATE_NANO_HZ << i,
> + 1000000000, &nhz);
> + if (hz == val && nhz == val2) {
> + return regmap_update_bits(data->regmap,
> + ADXL345_REG_BW_RATE,
> + ADXL345_BW_RATE, i);
> + }
> + }
But this one can be just loop-less.
Something like
res = div_s64_rem(val * 1000000000 + val2, ADXL345_BASE_RATE_NANO_HZ, &rem);
if (rem ...) // here to decide what margin is allowed, or choose
closest, or choose lower / higher.
return regmap...(..., res);
And I guess you might want to use NSEC_PER_SEC. (Is it really period
or frequency? If latter, perhaps add HZ_PER_GHZ macro, we have in one
driver HZ_PER_MHZ, maybe in the future they would be consolidated
somewhere).
--
With Best Regards,
Andy Shevchenko
--
To unsubscribe from this list: send the line "unsubscribe linux-iio" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
