TSC1641_POWER_LSB_UWATT
*val = regval * TSC1641_POWER_LSB_UWATT;
val = clamp_val(val, 0, TSC1641_POWER_LSB_UWATT * USHRT_MAX);
regval = DIV_ROUND_CLOSEST(val, TSC1641_POWER_LSB_UWATT);