/*
 * ESPRESSIF MIT License
 *
 * Copyright (c) 2016 <ESPRESSIF SYSTEMS (SHANGHAI) PTE LTD>
 *
 * Permission is hereby granted for use on ESPRESSIF SYSTEMS ESP8266 only, in which case,
 * it is free of charge, to any person obtaining a copy of this software and associated
 * documentation files (the "Software"), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the Software is furnished
 * to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all copies or
 * substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
 * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
 * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
 * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 *
 */
#include "ets_sys.h"
#include "osapi.h"
#include "gpio.h"
#include "driver/i2c_master.h"

LOCAL uint8_t m_nLastSDA;
LOCAL uint8_t m_nLastSCL;

/******************************************************************************
 * FunctionName : i2c_master_setDC
 * Description  : Internal used function -
 *                    set i2c SDA and SCL bit value for half clk cycle
 * Parameters   : uint8_t SDA
 *                uint8_t SCL
 * Returns      : NONE
*******************************************************************************/
LOCAL void ICACHE_FLASH_ATTR
i2c_master_setDC(uint8_t SDA, uint8_t SCL)
{
    SDA    &= 0x01;
    SCL    &= 0x01;
    m_nLastSDA = SDA;
    m_nLastSCL = SCL;

    if ((0 == SDA) && (0 == SCL)) {
        I2C_MASTER_SDA_LOW_SCL_LOW();
    } else if ((0 == SDA) && (1 == SCL)) {
        I2C_MASTER_SDA_LOW_SCL_HIGH();
    } else if ((1 == SDA) && (0 == SCL)) {
        I2C_MASTER_SDA_HIGH_SCL_LOW();
    } else {
        I2C_MASTER_SDA_HIGH_SCL_HIGH();
    }
}

/******************************************************************************
 * FunctionName : i2c_master_getDC
 * Description  : Internal used function -
 *                    get i2c SDA bit value
 * Parameters   : NONE
 * Returns      : uint8_t - SDA bit value
*******************************************************************************/
LOCAL uint8_t ICACHE_FLASH_ATTR
i2c_master_getDC(void)
{
    uint8_t sda_out;
    sda_out = GPIO_INPUT_GET(GPIO_ID_PIN(I2C_MASTER_SDA_GPIO));
    return sda_out;
}

/******************************************************************************
 * FunctionName : i2c_master_init
 * Description  : initilize I2C bus to enable i2c operations
 * Parameters   : NONE
 * Returns      : NONE
*******************************************************************************/
void ICACHE_FLASH_ATTR
i2c_master_init(void)
{
    uint8_t i;

    i2c_master_setDC(1, 0);
    i2c_master_wait(5);

    // when SCL = 0, toggle SDA to clear up
    i2c_master_setDC(0, 0) ;
    i2c_master_wait(5);
    i2c_master_setDC(1, 0) ;
    i2c_master_wait(5);

    // set data_cnt to max value
    for (i = 0; i < 28; i++) {
        i2c_master_setDC(1, 0);
        i2c_master_wait(5);    // sda 1, scl 0
        i2c_master_setDC(1, 1);
        i2c_master_wait(5);    // sda 1, scl 1
    }

    // reset all
    i2c_master_stop();
    return;
}

/******************************************************************************
 * FunctionName : i2c_master_gpio_init
 * Description  : config SDA and SCL gpio to open-drain output mode,
 *                mux and gpio num defined in i2c_master.h
 * Parameters   : NONE
 * Returns      : NONE
*******************************************************************************/
void ICACHE_FLASH_ATTR
i2c_master_gpio_init(void)
{
    ETS_GPIO_INTR_DISABLE() ;
//    ETS_INTR_LOCK();

    PIN_FUNC_SELECT(I2C_MASTER_SDA_MUX, I2C_MASTER_SDA_FUNC);
    PIN_FUNC_SELECT(I2C_MASTER_SCL_MUX, I2C_MASTER_SCL_FUNC);

    GPIO_REG_WRITE(GPIO_PIN_ADDR(GPIO_ID_PIN(I2C_MASTER_SDA_GPIO)), GPIO_REG_READ(GPIO_PIN_ADDR(GPIO_ID_PIN(I2C_MASTER_SDA_GPIO))) | GPIO_PIN_PAD_DRIVER_SET(GPIO_PAD_DRIVER_ENABLE)); //open drain;
    GPIO_REG_WRITE(GPIO_ENABLE_ADDRESS, GPIO_REG_READ(GPIO_ENABLE_ADDRESS) | (1 << I2C_MASTER_SDA_GPIO));
    GPIO_REG_WRITE(GPIO_PIN_ADDR(GPIO_ID_PIN(I2C_MASTER_SCL_GPIO)), GPIO_REG_READ(GPIO_PIN_ADDR(GPIO_ID_PIN(I2C_MASTER_SCL_GPIO))) | GPIO_PIN_PAD_DRIVER_SET(GPIO_PAD_DRIVER_ENABLE)); //open drain;
    GPIO_REG_WRITE(GPIO_ENABLE_ADDRESS, GPIO_REG_READ(GPIO_ENABLE_ADDRESS) | (1 << I2C_MASTER_SCL_GPIO));

    I2C_MASTER_SDA_HIGH_SCL_HIGH();

    ETS_GPIO_INTR_ENABLE() ;
//    ETS_INTR_UNLOCK();

    i2c_master_init();
}

/******************************************************************************
 * FunctionName : i2c_master_start
 * Description  : set i2c to send state
 * Parameters   : NONE
 * Returns      : NONE
*******************************************************************************/
void ICACHE_FLASH_ATTR
i2c_master_start(void)
{
    i2c_master_setDC(1, m_nLastSCL);
    i2c_master_wait(5);
    i2c_master_setDC(1, 1);
    i2c_master_wait(5);    // sda 1, scl 1
    i2c_master_setDC(0, 1);
    i2c_master_wait(5);    // sda 0, scl 1
}

/******************************************************************************
 * FunctionName : i2c_master_stop
 * Description  : set i2c to stop sending state
 * Parameters   : NONE
 * Returns      : NONE
*******************************************************************************/
void ICACHE_FLASH_ATTR
i2c_master_stop(void)
{
    i2c_master_wait(5);

    i2c_master_setDC(0, m_nLastSCL);
    i2c_master_wait(5);    // sda 0
    i2c_master_setDC(0, 1);
    i2c_master_wait(5);    // sda 0, scl 1
    i2c_master_setDC(1, 1);
    i2c_master_wait(5);    // sda 1, scl 1
}

/******************************************************************************
 * FunctionName : i2c_master_setAck
 * Description  : set ack to i2c bus as level value
 * Parameters   : uint8_t level - 0 or 1
 * Returns      : NONE
*******************************************************************************/
void ICACHE_FLASH_ATTR
i2c_master_setAck(uint8_t level)
{
    i2c_master_setDC(m_nLastSDA, 0);
    i2c_master_wait(5);
    i2c_master_setDC(level, 0);
    i2c_master_wait(5);    // sda level, scl 0
    i2c_master_setDC(level, 1);
    i2c_master_wait(8);    // sda level, scl 1
    i2c_master_setDC(level, 0);
    i2c_master_wait(5);    // sda level, scl 0
    i2c_master_setDC(1, 0);
    i2c_master_wait(5);
}

/******************************************************************************
 * FunctionName : i2c_master_getAck
 * Description  : confirm if peer send ack
 * Parameters   : NONE
 * Returns      : uint8_t - ack value, 0 or 1
*******************************************************************************/
uint8_t ICACHE_FLASH_ATTR
i2c_master_getAck(void)
{
    uint8_t retVal;
    i2c_master_setDC(m_nLastSDA, 0);
    i2c_master_wait(5);
    i2c_master_setDC(1, 0);
    i2c_master_wait(5);
    i2c_master_setDC(1, 1);
    i2c_master_wait(5);

    retVal = i2c_master_getDC();
    i2c_master_wait(5);
    i2c_master_setDC(1, 0);
    i2c_master_wait(5);

    return retVal;
}

/******************************************************************************
* FunctionName : i2c_master_checkAck
* Description  : get dev response
* Parameters   : NONE
* Returns      : true : get ack ; false : get nack
*******************************************************************************/
bool ICACHE_FLASH_ATTR
i2c_master_checkAck(void)
{
    if (i2c_master_getAck()) {
        return FALSE;
    } else {
        return TRUE;
    }
}

/******************************************************************************
* FunctionName : i2c_master_send_ack
* Description  : response ack
* Parameters   : NONE
* Returns      : NONE
*******************************************************************************/
void ICACHE_FLASH_ATTR
i2c_master_send_ack(void)
{
    i2c_master_setAck(0x0);
}
/******************************************************************************
* FunctionName : i2c_master_send_nack
* Description  : response nack
* Parameters   : NONE
* Returns      : NONE
*******************************************************************************/
void ICACHE_FLASH_ATTR
i2c_master_send_nack(void)
{
    i2c_master_setAck(0x1);
}

/******************************************************************************
 * FunctionName : i2c_master_readByte
 * Description  : read Byte from i2c bus
 * Parameters   : NONE
 * Returns      : uint8_t - readed value
*******************************************************************************/
uint8_t ICACHE_FLASH_ATTR
i2c_master_readByte(void)
{
    uint8_t retVal = 0;
    uint8_t k, i;

    i2c_master_wait(5);
    i2c_master_setDC(m_nLastSDA, 0);
    i2c_master_wait(5);    // sda 1, scl 0

    for (i = 0; i < 8; i++) {
        i2c_master_wait(5);
        i2c_master_setDC(1, 0);
        i2c_master_wait(5);    // sda 1, scl 0
        i2c_master_setDC(1, 1);
        i2c_master_wait(5);    // sda 1, scl 1

        k = i2c_master_getDC();
        i2c_master_wait(5);

        if (i == 7) {
            i2c_master_wait(3);   ////
        }

        k <<= (7 - i);
        retVal |= k;
    }

    i2c_master_setDC(1, 0);
    i2c_master_wait(5);    // sda 1, scl 0

    return retVal;
}

/******************************************************************************
 * FunctionName : i2c_master_writeByte
 * Description  : write wrdata value(one byte) into i2c
 * Parameters   : uint8_t wrdata - write value
 * Returns      : NONE
*******************************************************************************/
void ICACHE_FLASH_ATTR
i2c_master_writeByte(uint8_t wrdata)
{
    uint8_t dat;
    sint8 i;

    i2c_master_wait(5);

    i2c_master_setDC(m_nLastSDA, 0);
    i2c_master_wait(5);

    for (i = 7; i >= 0; i--) {
        dat = wrdata >> i;
        i2c_master_setDC(dat, 0);
        i2c_master_wait(5);
        i2c_master_setDC(dat, 1);
        i2c_master_wait(5);

        if (i == 0) {
            i2c_master_wait(3);   ////
        }

        i2c_master_setDC(dat, 0);
        i2c_master_wait(5);
    }
}
