i2c.c

/*
  i2c.c - I2C interface

  Grbl driver code for Texas Instruments Tiva C (TM4C123GH6PM) ARM processor

  Part of grblHAL

  Copyright (c) 2018-2021 Terje Io

  Grbl is free software: you can redistribute it and/or modify
  it under the terms of the GNU General Public License as published by
  the Free Software Foundation, either version 3 of the License, or
  (at your option) any later version.

  Grbl is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU General Public License for more details.

  You should have received a copy of the GNU General Public License
  along with Grbl.  If not, see <http://www.gnu.org/licenses/>.
*/

#include "i2c.h"

#if I2C_ENABLE

#if TRINAMIC_ENABLE && TRINAMIC_I2C
#define I2C_ADR_I2CBRIDGE 0x47
#endif

#define i2cIsBusy ((i2c.state != I2CState_Idle) || I2CMasterBusy(I2C1_BASE))

typedef enum {
    I2CState_Idle = 0,
    I2CState_SendNext,
    I2CState_SendLast,
    I2CState_SendRegisterAddress,
    I2CState_AwaitCompletion,
    I2CState_ReceiveNext,
    I2CState_ReceiveNextToLast,
    I2CState_ReceiveLast,
} i2c_state_t;

typedef struct {
    volatile i2c_state_t state;
    uint8_t addr;
    uint8_t count;
    uint8_t *data;
    keycode_callback_ptr keycode_callback;
    uint8_t buffer[8];
} i2c_trans_t;

static i2c_trans_t i2c;

static void I2C_interrupt_handler (void);

// get bytes (max 8), waits for result
static uint8_t* I2C_Receive (uint32_t i2cAddr, uint32_t bytes, bool block)
{
    i2c.data  = i2c.buffer;
    i2c.count = bytes;
    i2c.state = bytes == 1 ? I2CState_ReceiveLast : (bytes == 2 ? I2CState_ReceiveNextToLast : I2CState_ReceiveNext);

    I2CMasterSlaveAddrSet(I2C1_BASE, i2cAddr, true);
    I2CMasterControl(I2C1_BASE,  bytes == 1 ? I2C_MASTER_CMD_SINGLE_RECEIVE : I2C_MASTER_CMD_BURST_RECEIVE_START);

    if(block)
        while(i2cIsBusy);

    return i2c.buffer;
}

static void I2C_Send (uint32_t i2cAddr, uint8_t bytes, bool block)
{
    i2c.count = bytes - 1;
    i2c.data  = i2c.buffer;
    i2c.state = bytes == 1 ? I2CState_AwaitCompletion : (bytes == 2 ? I2CState_SendLast : I2CState_SendNext);
    I2CMasterSlaveAddrSet(I2C1_BASE, i2cAddr, false);
    I2CMasterDataPut(I2C1_BASE, *i2c.data++);
    I2CMasterControl(I2C1_BASE, bytes == 1 ? I2C_MASTER_CMD_SINGLE_SEND : I2C_MASTER_CMD_BURST_SEND_START);

    if(block)
        while(i2cIsBusy);
}

static uint8_t *I2C_ReadRegister (uint32_t i2cAddr, uint8_t bytes, bool block)
{
    while(i2cIsBusy);

    i2c.count = bytes;
    i2c.data  = i2c.buffer;
    i2c.state = I2CState_SendRegisterAddress;
    i2c.addr = i2cAddr;
    I2CMasterSlaveAddrSet(I2C1_BASE, i2cAddr, false);
    I2CMasterDataPut(I2C1_BASE, *i2c.data);
    I2CMasterControl(I2C1_BASE, I2C_MASTER_CMD_BURST_SEND_START);

    if(block)
        while(i2cIsBusy);

    return i2c.buffer;
}

void i2c_get_keycode (uint_fast16_t i2cAddr, keycode_callback_ptr callback)
{
    while(i2cIsBusy);

    i2c.keycode_callback = callback;

    I2C_Receive(i2cAddr, 1, false);
}

#if TRINAMIC_ENABLE && TRINAMIC_I2C

static uint8_t axis = 0xFF;

TMC_spi_status_t tmc_spi_read (trinamic_motor_t driver, TMC_spi_datagram_t *datagram)
{
    uint8_t *res;
    TMC_spi_status_t status = 0;

    while(i2cIsBusy);

    if(driver.axis != axis) {
        i2c.buffer[0] = driver.axis | 0x80;
        I2C_Send(I2C_ADR_I2CBRIDGE, 1, true);

        axis = driver.axis;
    }

    i2c.buffer[0] = datagram->addr.idx;
    i2c.buffer[1] = 0;
    i2c.buffer[2] = 0;
    i2c.buffer[3] = 0;
    i2c.buffer[4] = 0;

    res = I2C_ReadRegister(I2C_ADR_I2CBRIDGE, 5, true);

    status = (uint8_t)*res++;
    datagram->payload.value = ((uint8_t)*res++ << 24);
    datagram->payload.value |= ((uint8_t)*res++ << 16);
    datagram->payload.value |= ((uint8_t)*res++ << 8);
    datagram->payload.value |= (uint8_t)*res++;

    return status;
}

TMC_spi_status_t tmc_spi_write (trinamic_motor_t driver, TMC_spi_datagram_t *datagram)
{
    TMC_spi_status_t status = 0;

    while(i2cIsBusy);

    if(driver.axis != axis) {
        i2c.buffer[0] = driver.axis | 0x80;
        I2C_Send(I2C_ADR_I2CBRIDGE, 1, true);

        while(i2cIsBusy);

        axis = driver.axis;
    }

    datagram->addr.write = On;
    i2c.buffer[0] = datagram->addr.value;
    i2c.buffer[1] = (datagram->payload.value >> 24) & 0xFF;
    i2c.buffer[2] = (datagram->payload.value >> 16) & 0xFF;
    i2c.buffer[3] = (datagram->payload.value >> 8) & 0xFF;
    i2c.buffer[4] = datagram->payload.value & 0xFF;
    datagram->addr.write = Off;

    I2C_Send(I2C_ADR_I2CBRIDGE, 5, true);

    return status;
}

#endif

void i2c_init (void)
{
    SysCtlPeripheralEnable(SYSCTL_PERIPH_I2C1);
    SysCtlPeripheralReset(SYSCTL_PERIPH_I2C1);
    SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOA);

    GPIOPinConfigure(GPIO_PA6_I2C1SCL);
    GPIOPinConfigure(GPIO_PA7_I2C1SDA);
    GPIOPadConfigSet(GPIO_PORTA_BASE, GPIO_PIN_7, GPIO_STRENGTH_2MA, GPIO_PIN_TYPE_OD);

    GPIOPinTypeI2CSCL(GPIO_PORTA_BASE, GPIO_PIN_6);
    GPIOPinTypeI2C(GPIO_PORTA_BASE, GPIO_PIN_7);

    I2CMasterInitExpClk(I2C1_BASE, SysCtlClockGet(), false);
    I2CIntRegister(I2C1_BASE, I2C_interrupt_handler);

    I2CMasterIntClear(I2C1_BASE);
    I2CMasterIntEnable(I2C1_BASE);

    static const periph_pin_t scl = {
        .function = Output_SCK,
        .group = PinGroup_I2C,
        .port = (void *)GPIO_PORTA_BASE,
        .pin = 6,
        .mode = { .mask = PINMODE_OD }
    };

    static const periph_pin_t sda = {
        .function = Bidirectional_SDA,
        .group = PinGroup_I2C,
        .port = (void *)GPIO_PORTA_BASE,
        .pin = 7,
        .mode = { .mask = PINMODE_OD }
    };

    hal.periph_port.register_pin(&scl);
    hal.periph_port.register_pin(&sda);
}

static void I2C_interrupt_handler (void)
{
    // based on code from https://e2e.ti.com/support/microcontrollers/tiva_arm/f/908/t/169882
    // https://es.technikum-wien.at/ti-connected-launchpad/i2c_wrapper_public/blob/master/i2c_wrapper.c

    I2CMasterIntClear(I2C1_BASE);

//    if(I2CMasterErr(I2C1_BASE) == I2C_MASTER_ERR_NONE)

    switch(i2c.state) {

        case I2CState_Idle:
            break;

        case I2CState_SendNext:
            I2CMasterDataPut(I2C1_BASE, *i2c.data++);
            if(--i2c.count == 1)
                i2c.state = I2CState_SendLast;

            I2CMasterControl(I2C1_BASE, I2C_MASTER_CMD_BURST_SEND_CONT);
            break;

        case I2CState_SendLast:
            I2CMasterDataPut(I2C1_BASE, *i2c.data);
            I2CMasterControl(I2C1_BASE, I2C_MASTER_CMD_BURST_SEND_FINISH);
            i2c.state = I2CState_AwaitCompletion;
            break;

        case I2CState_AwaitCompletion:
            i2c.count = 0;
            i2c.state = I2CState_Idle;
            break;

        case I2CState_SendRegisterAddress:
            I2CMasterSlaveAddrSet(I2C1_BASE, i2c.addr, true);
            I2CMasterControl(I2C1_BASE,  i2c.count == 1 ? I2C_MASTER_CMD_SINGLE_RECEIVE : I2C_MASTER_CMD_BURST_RECEIVE_START);
            i2c.state = i2c.count == 1 ? I2CState_ReceiveLast : (i2c.count == 2 ? I2CState_ReceiveNextToLast : I2CState_ReceiveNext);
            break;

        case I2CState_ReceiveNext:
            *i2c.data++ = I2CMasterDataGet(I2C1_BASE);
            I2CMasterControl(I2C1_BASE, I2C_MASTER_CMD_BURST_RECEIVE_CONT);

            if(--i2c.count == 2)
                i2c.state = I2CState_ReceiveNextToLast;
            break;

        case I2CState_ReceiveNextToLast:
            *i2c.data++ = I2CMasterDataGet(I2C1_BASE);
            I2CMasterControl(I2C1_BASE, I2C_MASTER_CMD_BURST_RECEIVE_FINISH);

            i2c.count--;
            i2c.state = I2CState_ReceiveLast;
            break;

        case I2CState_ReceiveLast:
            *i2c.data = I2CMasterDataGet(I2C1_BASE);
            i2c.count = 0;
            i2c.state = I2CState_Idle;
          #if KEYPAD_ENABLE == 1
            if(i2c.keycode_callback) {
                //  if(GPIOIntStatus(I2C_STROBE_PORT, I2C_STROBE_PIN) != 0) { // only add keycode when key is still pressed
                i2c.keycode_callback(*i2c.data);
                i2c.keycode_callback = NULL;
            }
          #endif
            break;
    }
}

#endif