DUTY_CYCLE
regmap_write(priv->mmap, DUTY_CYCLE(desc->pin), brightness);
regmap_write(priv->mmap, DUTY_CYCLE(desc->pin), desc->brightness);
regmap_write(priv->mmap, DUTY_CYCLE(offset), 0xFF);
regmap_write(priv->mmap, DUTY_CYCLE(offset), 0x0);
err = regmap_write(priv->mmap, DUTY_CYCLE(i), 0);