For cpufreq example, it takes 13 steps (25 mV for one step) to increase
vddcore from 0.95 V to 1.275 V, and the time of 64 clock cycles at
24 MHz for one step is ~2.67 uS, so the total delay time would be
~34.71 uS. But the current calculation in the driver gives 39 uS.
Change the formula to have the addition of 1 be the last step, so that
we can get a more precise delay time. For example above, the new
formula will give 35 uS.
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
regmap_read(anatop_reg->anatop, anatop_reg->delay_reg, &val);
val = (val >> anatop_reg->delay_bit_shift) &
((1 << anatop_reg->delay_bit_width) - 1);
- ret = (new_sel - old_sel) * ((LDO_RAMP_UP_UNIT_IN_CYCLES <<
- val) / LDO_RAMP_UP_FREQ_IN_MHZ + 1);
+ ret = (new_sel - old_sel) * (LDO_RAMP_UP_UNIT_IN_CYCLES <<
+ val) / LDO_RAMP_UP_FREQ_IN_MHZ + 1;
}
return ret;