text: // Copyright 2015-2017 Espressif Systems (Shanghai) PTE LTD
  //
  // Licensed under the Apache License, Version 2.0 (the "License");
  // you may not use this file except in compliance with the License.
  // You may obtain a copy of the License at
  //
  //     http://www.apache.org/licenses/LICENSE-2.0
  //
  // Unless required by applicable law or agreed to in writing, software
  // distributed under the License is distributed on an "AS IS" BASIS,
  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  // See the License for the specific language governing permissions and
  // limitations under the License.
  
  #pragma once
  
  #include "i2c_apll.h"
  #include "i2c_bbpll.h"
  
  /* Analog function control register */
  #define ANA_CONFIG_REG  0x6000E044
  #define ANA_CONFIG_S    (8)
  #define ANA_CONFIG_M    (0x3FF)
  /* Clear to enable APLL */
  #define I2C_APLL_M      (BIT(14))
  /* Clear to enable BBPLL */
  #define I2C_BBPLL_M     (BIT(17))
  
  /* ROM functions which read/write internal control bus */
  uint8_t rom_i2c_readReg(uint8_t block, uint8_t host_id, uint8_t reg_add);
  uint8_t rom_i2c_readReg_Mask(uint8_t block, uint8_t host_id, uint8_t reg_add, uint8_t msb, uint8_t lsb);
  void rom_i2c_writeReg(uint8_t block, uint8_t host_id, uint8_t reg_add, uint8_t data);
  void rom_i2c_writeReg_Mask(uint8_t block, uint8_t host_id, uint8_t reg_add, uint8_t msb, uint8_t lsb, uint8_t data);
  
  /* Convenience macros for the above functions, these use register definitions
   * from i2c_apll.h/i2c_bbpll.h header files.
   */
  #define I2C_WRITEREG_MASK_RTC(block, reg_add, indata) \
        rom_i2c_writeReg_Mask(block, block##_HOSTID,  reg_add,  reg_add##_MSB,  reg_add##_LSB,  indata)
  
  #define I2C_READREG_MASK_RTC(block, reg_add) \
        rom_i2c_readReg_Mask(block, block##_HOSTID,  reg_add,  reg_add##_MSB,  reg_add##_LSB)
  
  #define I2C_WRITEREG_RTC(block, reg_add, indata) \
        rom_i2c_writeReg(block, block##_HOSTID,  reg_add, indata)
  
  #define I2C_READREG_RTC(block, reg_add) \
        rom_i2c_readReg(block, block##_HOSTID,  reg_add)
  