fan_from_reg16
fan_from_reg16(data->target_speed[nr],
tolerance = (fan_from_reg16(low, data->fan_div[nr])
- fan_from_reg16(high, data->fan_div[nr])) / 2;
high = fan_from_reg16(data->target_speed[nr], data->fan_div[nr]) + val;
low = fan_from_reg16(data->target_speed[nr], data->fan_div[nr]) - val;
data->fan_from_reg = fan_from_reg16;