REG_BL_CONF_4
ret = regmap_write(pchip->regmap, REG_BL_CONF_4, bl->props.brightness);
ret = regmap_read(pchip->regmap, REG_BL_CONF_4, ®_val);
ret = regmap_write(pchip->regmap, REG_BL_CONF_4, pdata->init_brt_led);