REG_BRT_B
rval |= lm3630a_write(pchip, REG_BRT_B, pdata->ledb_init_brt);
ret = lm3630a_write(pchip, REG_BRT_B, brightness);
rval = lm3630a_read(pchip, REG_BRT_B);
rval = lm3630a_write(pchip, REG_BRT_B, 0);