235 lines
6.3 KiB
C
235 lines
6.3 KiB
C
/*
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* This file is part of the MicroPython project, http://micropython.org/
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*
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* The MIT License (MIT)
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*
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* Copyright (c) 2018 Damien P. George
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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#include "py/mperrno.h"
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#include "py/mphal.h"
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#include "i2c.h"
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#if MICROPY_HW_ENABLE_HW_I2C
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#if defined(STM32F7)
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#define I2C_POLL_TIMEOUT_MS (50)
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int i2c_init(i2c_t *i2c, mp_hal_pin_obj_t scl, mp_hal_pin_obj_t sda, uint32_t freq) {
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uint32_t i2c_id = ((uint32_t)i2c - I2C1_BASE) / (I2C2_BASE - I2C1_BASE);
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// Init pins
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if (!mp_hal_pin_config_alt(scl, MP_HAL_PIN_MODE_ALT_OPEN_DRAIN, MP_HAL_PIN_PULL_UP, AF_FN_I2C, i2c_id + 1)) {
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return -MP_EPERM;
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}
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if (!mp_hal_pin_config_alt(sda, MP_HAL_PIN_MODE_ALT_OPEN_DRAIN, MP_HAL_PIN_PULL_UP, AF_FN_I2C, i2c_id + 1)) {
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return -MP_EPERM;
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}
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// Enable I2C peripheral clock
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RCC->APB1ENR |= RCC_APB1ENR_I2C1EN << i2c_id;
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volatile uint32_t tmp = RCC->APB1ENR; // delay after RCC clock enable
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(void)tmp;
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// Initialise I2C peripheral
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i2c->CR1 = 0;
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i2c->CR2 = 0;
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i2c->OAR1 = 0;
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i2c->OAR2 = 0;
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// These timing values are for f_I2CCLK=54MHz and are only approximate
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if (freq >= 1000000) {
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i2c->TIMINGR = 0x50100103;
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} else if (freq >= 400000) {
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i2c->TIMINGR = 0x70330309;
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} else if (freq >= 100000) {
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i2c->TIMINGR = 0xb0420f13;
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} else {
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return -MP_EINVAL;
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}
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i2c->TIMEOUTR = 0;
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return 0;
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}
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STATIC int i2c_wait_cr2_clear(i2c_t *i2c, uint32_t mask) {
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uint32_t t0 = HAL_GetTick();
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while (i2c->CR2 & mask) {
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if (HAL_GetTick() - t0 >= I2C_POLL_TIMEOUT_MS) {
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i2c->CR1 &= ~I2C_CR1_PE;
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return -MP_ETIMEDOUT;
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}
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}
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return 0;
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}
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STATIC int i2c_wait_isr_set(i2c_t *i2c, uint32_t mask) {
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uint32_t t0 = HAL_GetTick();
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while (!(i2c->ISR & mask)) {
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if (HAL_GetTick() - t0 >= I2C_POLL_TIMEOUT_MS) {
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i2c->CR1 &= ~I2C_CR1_PE;
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return -MP_ETIMEDOUT;
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}
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}
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return 0;
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}
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// len = 0, 1 or N
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int i2c_start_addr(i2c_t *i2c, int rd_wrn, uint16_t addr, size_t len, bool stop) {
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// Enable the peripheral and send the START condition with slave address
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i2c->CR1 |= I2C_CR1_PE;
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i2c->CR2 = stop << I2C_CR2_AUTOEND_Pos
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| (len > 1) << I2C_CR2_RELOAD_Pos
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| (len > 0) << I2C_CR2_NBYTES_Pos
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| rd_wrn << I2C_CR2_RD_WRN_Pos
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| (addr & 0x7f) << 1;
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i2c->CR2 |= I2C_CR2_START;
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// Wait for address to be sent
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int ret;
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if ((ret = i2c_wait_cr2_clear(i2c, I2C_CR2_START))) {
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return ret;
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}
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// Check if the slave responded or not
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if (i2c->ISR & I2C_ISR_NACKF) {
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// If we get a NACK then I2C periph releases the bus, so don't send STOP
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i2c->CR1 &= ~I2C_CR1_PE;
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return -MP_ENODEV;
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}
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// Repurpose OAR1 to indicate that we loaded CR2
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i2c->OAR1 = 1;
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return 0;
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}
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STATIC int i2c_check_stop(i2c_t *i2c) {
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if (i2c->CR2 & I2C_CR2_AUTOEND) {
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// Wait for the STOP condition and then disable the peripheral
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int ret;
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if ((ret = i2c_wait_isr_set(i2c, I2C_ISR_STOPF))) {
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return ret;
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}
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i2c->CR1 &= ~I2C_CR1_PE;
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}
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return 0;
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}
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// next_len = 0 or N
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int i2c_read(i2c_t *i2c, uint8_t *dest, size_t len, size_t next_len) {
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if (i2c->OAR1) {
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i2c->OAR1 = 0;
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} else {
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goto load_cr2;
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}
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// Read in the data
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while (len--) {
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int ret;
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if ((ret = i2c_wait_isr_set(i2c, I2C_ISR_RXNE))) {
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return ret;
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}
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*dest++ = i2c->RXDR;
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load_cr2:
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if (len) {
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i2c->CR2 = (i2c->CR2 & I2C_CR2_AUTOEND)
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| (len + next_len > 1) << I2C_CR2_RELOAD_Pos
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| 1 << I2C_CR2_NBYTES_Pos;
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}
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}
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if (!next_len) {
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int ret;
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if ((ret = i2c_check_stop(i2c))) {
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return ret;
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}
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}
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return 0;
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}
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// next_len = 0 or N
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int i2c_write(i2c_t *i2c, const uint8_t *src, size_t len, size_t next_len) {
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int num_acks = 0;
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if (i2c->OAR1) {
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i2c->OAR1 = 0;
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} else {
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goto load_cr2;
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}
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// Write out the data
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while (len--) {
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int ret;
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if ((ret = i2c_wait_isr_set(i2c, I2C_ISR_TXE))) {
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return ret;
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}
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i2c->TXDR = *src++;
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if ((ret = i2c_wait_isr_set(i2c, I2C_ISR_TCR | I2C_ISR_TC | I2C_ISR_STOPF))) {
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return ret;
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}
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if (i2c->ISR & I2C_ISR_NACKF) {
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// Slave did not respond to byte so stop sending
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break;
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}
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++num_acks;
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load_cr2:
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if (len) {
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i2c->CR2 = (i2c->CR2 & I2C_CR2_AUTOEND)
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| (len + next_len > 1) << I2C_CR2_RELOAD_Pos
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| 1 << I2C_CR2_NBYTES_Pos;
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}
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}
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if (!next_len) {
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int ret;
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if ((ret = i2c_check_stop(i2c))) {
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return ret;
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}
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}
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return num_acks;
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}
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int i2c_readfrom(i2c_t *i2c, uint16_t addr, uint8_t *dest, size_t len, bool stop) {
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int ret;
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if ((ret = i2c_start_addr(i2c, 1, addr, len, stop))) {
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return ret;
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}
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return i2c_read(i2c, dest, len, 0);
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}
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int i2c_writeto(i2c_t *i2c, uint16_t addr, const uint8_t *src, size_t len, bool stop) {
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int ret;
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if ((ret = i2c_start_addr(i2c, 0, addr, len, stop))) {
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return ret;
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}
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return i2c_write(i2c, src, len, 0);
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}
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#endif // defined(STM32F7)
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#endif // MICROPY_HW_ENABLE_HW_I2C
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