mirror of https://github.com/ARMmbed/mbed-os.git
139 lines
3.3 KiB
C++
139 lines
3.3 KiB
C++
/* Simple access class for I2C EEPROM chips like Microchip 24LC
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* Copyright (c) 2015 Robin Hourahane
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include "I2CEEBlockDevice.h"
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#define I2CEE_TIMEOUT 10000
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I2CEEBlockDevice::I2CEEBlockDevice(
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PinName sda, PinName scl, uint8_t addr,
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bd_size_t size, bd_size_t block, int freq)
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: _i2c(sda, scl), _i2c_addr(addr), _size(size), _block(block)
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{
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_i2c.frequency(freq);
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}
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bd_error_t I2CEEBlockDevice::init()
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{
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return _sync();
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}
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bd_error_t I2CEEBlockDevice::deinit()
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{
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return 0;
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}
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bd_error_t I2CEEBlockDevice::read(void *buffer, bd_addr_t addr, bd_size_t size)
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{
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// Check the address and size fit onto the chip.
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if (!is_valid_read(addr, size)) {
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return BD_ERROR_PARAMETER;
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}
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_i2c.start();
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if (!_i2c.write(_i2c_addr | 0) ||
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!_i2c.write((char)(addr >> 8)) ||
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!_i2c.write((char)(addr & 0xff))) {
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return BD_ERROR_DEVICE_ERROR;
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}
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_i2c.stop();
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if (_i2c.read(_i2c_addr, static_cast<char*>(buffer), size) < 0) {
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return BD_ERROR_DEVICE_ERROR;
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}
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return 0;
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}
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bd_error_t I2CEEBlockDevice::program(const void *buffer, bd_addr_t addr, bd_size_t size)
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{
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// Check the addr and size fit onto the chip.
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if (!is_valid_program(addr, size)) {
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return BD_ERROR_PARAMETER;
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}
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// While we have some more data to write.
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while (size > 0) {
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uint32_t off = addr % _block;
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uint32_t chunk = (off + size < _block) ? size : (_block - off);
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_i2c.start();
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if (!_i2c.write(_i2c_addr | 0) ||
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!_i2c.write((char)(addr >> 8)) ||
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!_i2c.write((char)(addr & 0xff))) {
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return BD_ERROR_DEVICE_ERROR;
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}
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for (unsigned i = 0; i < chunk; i++) {
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_i2c.write(static_cast<const char*>(buffer)[i]);
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}
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_i2c.stop();
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bd_error_t err = _sync();
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if (err) {
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return err;
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}
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addr += chunk;
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size -= chunk;
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buffer = static_cast<const char*>(buffer) + chunk;
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}
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return 0;
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}
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bd_error_t I2CEEBlockDevice::erase(bd_addr_t addr, bd_size_t size)
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{
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// No erase needed
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return 0;
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}
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bd_error_t I2CEEBlockDevice::_sync()
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{
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// The chip doesn't ACK while writing to the actual EEPROM
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// so loop trying to do a zero byte write until it is ACKed
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// by the chip.
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for (int i = 0; i < I2CEE_TIMEOUT; i++) {
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if (_i2c.write(_i2c_addr | 0, 0, 0) < 1) {
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return 0;
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}
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wait_ms(1);
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}
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return BD_ERROR_DEVICE_ERROR;
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}
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bd_size_t I2CEEBlockDevice::get_read_size()
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{
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return 1;
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}
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bd_size_t I2CEEBlockDevice::get_program_size()
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{
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return 1;
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}
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bd_size_t I2CEEBlockDevice::get_erase_size()
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{
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return 1;
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}
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bd_size_t I2CEEBlockDevice::size()
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{
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return _size;
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}
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