/* 
 * (c) danielinux 2019
 * GPLv.2
 *
 * See LICENSE for details
 */
#include <stdint.h>
#include <stdlib.h>
#include "system.h"
#include "i2c.h"
#include "display.h"
#define DISPLAY_I2C_ADDR 0x3C


#define I2C1 (0x40005400)
#define APB1_SPEED_IN_MHZ (42)
#define I2C1_CR1        (*(volatile uint32_t *)(I2C1))
#define I2C1_CR2        (*(volatile uint32_t *)(I2C1 + 0x04))
#define I2C1_OAR1       (*(volatile uint32_t *)(I2C1 + 0x08))
#define I2C1_OAR2       (*(volatile uint32_t *)(I2C1 + 0x0c))
#define I2C1_DR         (*(volatile uint32_t *)(I2C1 + 0x10))
#define I2C1_SR1        (*(volatile uint32_t *)(I2C1 + 0x14))
#define I2C1_SR2        (*(volatile uint32_t *)(I2C1 + 0x18))
#define I2C1_CCR        (*(volatile uint32_t *)(I2C1 + 0x1c))
#define I2C1_TRISE      (*(volatile uint32_t *)(I2C1 + 0x20))

#define I2C_CR1_ENABLE               (1 << 0)
#define I2C_CR1_START			     (1 << 8)
#define I2C_CR1_STOP			     (1 << 9)
#define I2C_CR1_ACK			         (1 << 10)
#define I2C_CR2_FREQ_MASK            (0x3ff)
#define I2C_CCR_MASK                 (0xfff)
#define I2C_TRISE_MASK                (0x3f)


#define I2C_SR1_START                   (1 << 0)
#define I2C_SR1_TX_BTF                  (1 << 2)
#define I2C_SR1_ADDR_SENT               (1 << 1)
#define I2C_SR1_RX_NOTEMPTY  	        (1 << 6)
#define I2C_SR1_TX_EMPTY			    (1 << 7)


#define I2C_SR2_MASTER              (1 << 0)
#define I2C_SR2_BUSY                (1 << 1)
#define I2C_SR2_XMIT                (1 << 2)

#define APB1_CLOCK_ER           (*(volatile uint32_t *)(0x40023840))
#define APB1_CLOCK_RST          (*(volatile uint32_t *)(0x40023820))
#define I2C1_APB1_CLOCK_ER_VAL 	(1 << 21)


static void i2c1_pins_setup(void)
{
    uint32_t reg;
    AHB1_CLOCK_ER |= GPIOB_AHB1_CLOCK_ER;
    /* Set mode = AF */
    reg = GPIOB_MODE & ~ (0x03 << (I2C1_SCL * 2));
    GPIOB_MODE = reg | (2 << (I2C1_SCL * 2));
    reg = GPIOB_MODE & ~ (0x03 << (I2C1_SDA * 2));
    GPIOB_MODE = reg | (2 << (I2C1_SDA * 2));

    /* Alternate function: */
    reg =  GPIOB_AFH & ~(0xf << ((I2C1_SCL - 8) * 4));
    GPIOB_AFH = reg | (I2C1_PIN_AF << ((I2C1_SCL - 8) * 4));
    reg =  GPIOB_AFH & ~(0xf << ((I2C1_SDA - 8) * 4));
    GPIOB_AFH = reg | (I2C1_PIN_AF << ((I2C1_SDA - 8) * 4));
}

static void i2c1_reset(void)
{
    APB1_CLOCK_RST |= I2C1_APB1_CLOCK_ER_VAL;
    APB1_CLOCK_RST &= ~I2C1_APB1_CLOCK_ER_VAL;
}

static void i2c1_send_start(void)
{
    volatile uint32_t sr1;
    I2C1_CR1 |= I2C_CR1_START;
    do {
        sr1 = I2C1_SR1;
    } while ((sr1 & I2C_SR1_START) == 0);;
}

static void i2c1_send_stop(void)
{
    I2C1_CR1 |= I2C_CR1_STOP;
}

void display_send_data(void *priv, const uint8_t *buf, int len)
{
    volatile uint32_t sr1, sr2;
    int i;
    volatile uint8_t drval;
    uint32_t start_data = 0x00000040;
    uint8_t address = DISPLAY_I2C_ADDR;
    I2C1_CR1 &= ~I2C_CR1_ENABLE;
    I2C1_CR1 &= ~I2C_CR1_STOP;
    I2C1_CR1 &= ~I2C_CR1_ACK;
    I2C1_CR1 |= I2C_CR1_ENABLE;

    /* Wait if the bus is busy */
    do {
        sr2 = I2C1_SR2;
    } while ((sr2 & I2C_SR2_BUSY) != 0);;
    
    
    /* Send a start condition */
    i2c1_send_start();

    /* Send address + R/W = 0 */
    I2C1_DR = (address << 1);

    do {
        sr1 = I2C1_SR1;
    } while ((sr1 & I2C_SR1_ADDR_SENT) != I2C_SR1_ADDR_SENT);

    do {
        sr2 = I2C1_SR2;
    } while ((sr2 & (I2C_SR2_BUSY | I2C_SR2_MASTER)) != (I2C_SR2_BUSY | I2C_SR2_MASTER));;

    I2C1_DR = start_data;
    do {
        sr1 = I2C1_SR1;
    } while ((sr1 & (I2C_SR1_TX_EMPTY)) == 0);

    for (i = 0; i < len; i++) {
        I2C1_DR = buf[i];
        do {
            sr1 = I2C1_SR1;
            if ((sr1 & I2C_SR1_RX_NOTEMPTY) == I2C_SR1_RX_NOTEMPTY) {
                drval = I2C1_DR;
            }
        } while ((sr1 & (I2C_SR1_TX_EMPTY)) == 0);
    }
    while ((sr1 & (I2C_SR1_TX_BTF)) == 0) {
        sr1 = I2C1_SR1;
    }
    i2c1_send_stop();
}


int i2c1_send(uint8_t address, const uint8_t *buf, int len)
{
    volatile uint32_t sr1, sr2;
    int i;
    volatile uint8_t drval;
    I2C1_CR1 &= ~I2C_CR1_ENABLE;
    I2C1_CR1 &= ~I2C_CR1_STOP;
    I2C1_CR1 &= ~I2C_CR1_ACK;
    I2C1_CR1 |= I2C_CR1_ENABLE;

    /* Wait if the bus is busy */
    do {
        sr2 = I2C1_SR2;
    } while ((sr2 & I2C_SR2_BUSY) != 0);;
    
    
    /* Send a start condition */
    i2c1_send_start();

    /* Send address + R/W = 0 */
    I2C1_DR = (address << 1);

    do {
        sr1 = I2C1_SR1;
    } while ((sr1 & I2C_SR1_ADDR_SENT) != I2C_SR1_ADDR_SENT);

    do {
        sr2 = I2C1_SR2;
    } while ((sr2 & (I2C_SR2_BUSY | I2C_SR2_MASTER)) != (I2C_SR2_BUSY | I2C_SR2_MASTER));;

    for (i = 0; i < len; i++) {
        I2C1_DR = buf[i];
        do {
            sr1 = I2C1_SR1;
            if ((sr1 & I2C_SR1_RX_NOTEMPTY) == I2C_SR1_RX_NOTEMPTY) {
                drval = I2C1_DR;
            }
        } while ((sr1 & (I2C_SR1_TX_EMPTY)) == 0);
    }
    while ((sr1 & (I2C_SR1_TX_BTF)) == 0) {
        sr1 = I2C1_SR1;
    }
    i2c1_send_stop();
    return i;
}

void i2c1_setup(void)
{
    uint32_t reg;
    i2c1_pins_setup();
    APB1_CLOCK_ER |= I2C1_APB1_CLOCK_ER_VAL;
    I2C1_CR1 &= ~I2C_CR1_ENABLE;
    i2c1_reset();

    reg =   I2C1_CR2 & ~(I2C_CR2_FREQ_MASK);
    I2C1_CR2 = reg | APB1_SPEED_IN_MHZ;

    reg =   I2C1_CCR & ~(I2C_CCR_MASK);
//    I2C1_CCR = reg | (APB1_SPEED_IN_MHZ * 5);
  I2C1_CCR = reg | 35;
        
    reg = I2C1_TRISE & ~(I2C_TRISE_MASK);
    I2C1_TRISE = reg | (APB1_SPEED_IN_MHZ + 1);

    I2C1_CR1 |= I2C_CR1_ENABLE;
}

void i2c_display_init(void)
{
    i2c1_setup();
    display_init(NULL);
}

void display_send_cmd(void *priv, uint8_t cmd)
{
    uint8_t buf[2] = {0x00, cmd};
    volatile int j;
    i2c1_send(DISPLAY_I2C_ADDR, buf, 2);
}

void display_send_cmd1(void *priv, uint8_t cmd, uint8_t arg1)
{
    uint8_t buf[3] = {0x00, cmd, arg1};
    volatile int j;
    i2c1_send(DISPLAY_I2C_ADDR, buf, 3);
}

void display_send_cmd2(void *priv, uint8_t cmd, uint8_t arg1, uint8_t arg2)
{
    uint8_t buf[4] = {0x00, cmd, arg1, arg2};
    volatile int j;
    i2c1_send(DISPLAY_I2C_ADDR, buf, 3);
}