circuitpython/ports/stm32f4/common-hal/busio/I2C.c

/*
 * This file is part of the MicroPython project, http://micropython.org/
 *
 * The MIT License (MIT)
 *
 * Copyright (c) 2016 Scott Shawcroft
 * Copyright (c) 2019 Lucian Copeland for Adafruit Industries
 *
 * Permission is hereby granted, 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 "shared-bindings/busio/I2C.h"
#include "py/mperrno.h"
#include "py/runtime.h"
#include "stm32f4xx_hal.h"

#include "shared-bindings/microcontroller/__init__.h"
#include "supervisor/shared/translate.h"
#include "common-hal/microcontroller/Pin.h"
#include "stm32f4/periph.h"

STATIC I2C_HandleTypeDef hi2c;

STATIC I2C_TypeDef * I2Cbanks[3] = 
{
#ifdef I2C1
    I2C1, 
#else 
    NULL,
#endif
#ifdef I2C2
    I2C2,
#else
    NULL,
#endif
#ifdef I2C3
    I2C3
#else
    NULL
#endif
};

void common_hal_busio_i2c_construct(busio_i2c_obj_t *self,
        const mcu_pin_obj_t* scl, const mcu_pin_obj_t* sda, uint32_t frequency, uint32_t timeout) {

    I2C_TypeDef * I2Cx;
    uint8_t i2cidx = 0;
    uint8_t i2cidx_c = 0;
    uint8_t len = sizeof(mcu_i2c_list)/sizeof(*mcu_i2c_list);
    for(uint i=0; i<len;i++) {
        if (mcu_i2c_list[i]->sda_pin == sda) {
            i2cidx = mcu_i2c_list[i]->i2c_index;
        }
        if (mcu_i2c_list[i]->scl_pin == scl) {
            i2cidx_c = mcu_i2c_list[i]->i2c_index;
        }
    }
    if(i2cidx == i2cidx_c) {
        if(I2Cbanks[i2cidx] == NULL || i2cidx>=len) {
            mp_raise_RuntimeError(translate("Bad I2C pin definition, check peripheral files"));
        }
        I2Cx = I2Cbanks[i2cidx];
    } else {
        mp_raise_RuntimeError(translate("Invalid I2C pin selection"));
    } 

    GPIO_InitTypeDef GPIO_InitStruct = {0};
    GPIO_InitStruct.Pin = pin_mask(sda->number)|pin_mask(scl->number);
    GPIO_InitStruct.Mode = GPIO_MODE_AF_OD;
    GPIO_InitStruct.Pull = GPIO_PULLUP;
    GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
    GPIO_InitStruct.Alternate = GPIO_AF4_I2C1; //TODO; custom per pin? Or error if mixed is bad.
    HAL_GPIO_Init(pin_port(sda->port), &GPIO_InitStruct);
    __HAL_RCC_I2C1_CLK_ENABLE(); //TODO custom per periph

    hi2c.Instance = I2Cx;
    hi2c.Init.ClockSpeed = 100000;
    hi2c.Init.DutyCycle = I2C_DUTYCYCLE_2;
    hi2c.Init.OwnAddress1 = 0;
    hi2c.Init.AddressingMode = I2C_ADDRESSINGMODE_7BIT;
    hi2c.Init.DualAddressMode = I2C_DUALADDRESS_DISABLE;
    hi2c.Init.OwnAddress2 = 0;
    hi2c.Init.GeneralCallMode = I2C_GENERALCALL_DISABLE;
    hi2c.Init.NoStretchMode = I2C_NOSTRETCH_DISABLE;
    if(HAL_I2C_Init(&hi2c) != HAL_OK) {
        mp_raise_RuntimeError(translate("I2C Init Error"));
    } else {
        mp_printf(&mp_plat_print, "I2C INIT OK");
    }

    self->sda_pin = sda;
    self->scl_pin = scl;

    claim_pin(sda);
    claim_pin(scl);
}

bool common_hal_busio_i2c_deinited(busio_i2c_obj_t *self) {
    return self->sda_pin == NULL;
}

void common_hal_busio_i2c_deinit(busio_i2c_obj_t *self) {
    if (common_hal_busio_i2c_deinited(self)) {
        return;
    }

    HAL_I2C_MspDeInit(&hi2c);

    self->sda_pin = NULL;
    self->scl_pin = NULL;
}

bool common_hal_busio_i2c_probe(busio_i2c_obj_t *self, uint8_t addr) {
    return HAL_I2C_IsDeviceReady(&hi2c, (uint16_t)(addr<<1),2,2) == HAL_OK;
}

bool common_hal_busio_i2c_try_lock(busio_i2c_obj_t *self) {
    bool grabbed_lock = false;

    //Critical section code that may be required at some point. 
    // uint32_t store_primask = __get_PRIMASK();
    // __disable_irq();
    // __DMB();

        if (!self->has_lock) {
            grabbed_lock = true;
            self->has_lock = true;
        }

    // __DMB();
    // __set_PRIMASK(store_primask);

    return grabbed_lock;
}

bool common_hal_busio_i2c_has_lock(busio_i2c_obj_t *self) {
    return self->has_lock;
}

void common_hal_busio_i2c_unlock(busio_i2c_obj_t *self) {
    self->has_lock = false;
}

uint8_t common_hal_busio_i2c_write(busio_i2c_obj_t *self, uint16_t addr,
                                   const uint8_t *data, size_t len, bool transmit_stop_bit) {
    return HAL_I2C_Master_Transmit(&hi2c, (uint16_t)(addr<<1), (uint8_t *)data, (uint16_t)len, 2) == HAL_OK ? 0 : MP_EIO;
}

uint8_t common_hal_busio_i2c_read(busio_i2c_obj_t *self, uint16_t addr,
        uint8_t *data, size_t len) {
    return HAL_I2C_Master_Receive(&hi2c, (uint16_t)(addr<<1), data, (uint16_t)len, 2) == HAL_OK ? 0 : MP_EIO;
}