I2CFCR
OUT32(id, I2CFCR, FCR_RFRST | FCR_TFRST);
OUT32(id, I2CFCR, FCR_TFRST | ((len & 0xf) << 4));
OUT32(id, I2CFCR,
OUT32(id, I2CFCR, FCR_RFRST | FCR_TFRST);
OUT32(id, I2CFCR, FCR_TFRST | ((len & 0xF) << 4));
OUT32(id, I2CFCR, FCR_RFRST | FCR_TFRST);
OUT32(id, I2CFCR, FCR_RFRST | ((len & 3) << 2));
OUT32(id, I2CFCR, FCR_RFRST | FCR_TFRST);