ktz8866_write
ktz8866_write(ktz, BL_EN, BIT(val) - 1);
ktz8866_write(ktz, BL_EN, BIT(6) - 1);
ktz8866_write(ktz, BL_CFG2, BIT(7) | (ilog2(val) << 3) | PWM_HYST);
ktz8866_write(ktz, BL_CFG2, BIT(7) | ((5 + val / 64) << 3) | PWM_HYST);
ktz8866_write(ktz, BL_DIMMING, 0);
ktz8866_write(ktz, BL_DIMMING, ramp_on_time | ramp_off_time);
ktz8866_write(ktz, LCD_BIAS_CFG1, LCD_BIAS_EN);
ktz8866_write(ktz, BL_BRT_LSB, brightness & 0x7);
ktz8866_write(ktz, BL_BRT_MSB, (brightness >> 3) & 0xFF);