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mbed-dev/drivers/I2C.cpp@1:d0dfbce63a89, 2017-02-24 (annotated)

Committer:
elmot
Date:
Fri Feb 24 21:13:56 2017 +0000
Revision:
1:d0dfbce63a89
Ready-to-copy

Who changed what in which revision?

UserRevisionLine numberNew contents of line
elmot 1:d0dfbce63a89 1 /* mbed Microcontroller Library
elmot 1:d0dfbce63a89 2 * Copyright (c) 2006-2015 ARM Limited
elmot 1:d0dfbce63a89 3 *
elmot 1:d0dfbce63a89 4 * Licensed under the Apache License, Version 2.0 (the "License");
elmot 1:d0dfbce63a89 5 * you may not use this file except in compliance with the License.
elmot 1:d0dfbce63a89 6 * You may obtain a copy of the License at
elmot 1:d0dfbce63a89 7 *
elmot 1:d0dfbce63a89 8 * http://www.apache.org/licenses/LICENSE-2.0
elmot 1:d0dfbce63a89 9 *
elmot 1:d0dfbce63a89 10 * Unless required by applicable law or agreed to in writing, software
elmot 1:d0dfbce63a89 11 * distributed under the License is distributed on an "AS IS" BASIS,
elmot 1:d0dfbce63a89 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
elmot 1:d0dfbce63a89 13 * See the License for the specific language governing permissions and
elmot 1:d0dfbce63a89 14 * limitations under the License.
elmot 1:d0dfbce63a89 15 */
elmot 1:d0dfbce63a89 16 #include "drivers/I2C.h"
elmot 1:d0dfbce63a89 17
elmot 1:d0dfbce63a89 18 #if DEVICE_I2C
elmot 1:d0dfbce63a89 19
elmot 1:d0dfbce63a89 20 namespace mbed {
elmot 1:d0dfbce63a89 21
elmot 1:d0dfbce63a89 22 I2C *I2C::_owner = NULL;
elmot 1:d0dfbce63a89 23 SingletonPtr<PlatformMutex> I2C::_mutex;
elmot 1:d0dfbce63a89 24
elmot 1:d0dfbce63a89 25 I2C::I2C(PinName sda, PinName scl) :
elmot 1:d0dfbce63a89 26 #if DEVICE_I2C_ASYNCH
elmot 1:d0dfbce63a89 27 _irq(this), _usage(DMA_USAGE_NEVER),
elmot 1:d0dfbce63a89 28 #endif
elmot 1:d0dfbce63a89 29 _i2c(), _hz(100000) {
elmot 1:d0dfbce63a89 30 // No lock needed in the constructor
elmot 1:d0dfbce63a89 31
elmot 1:d0dfbce63a89 32 // The init function also set the frequency to 100000
elmot 1:d0dfbce63a89 33 i2c_init(&_i2c, sda, scl);
elmot 1:d0dfbce63a89 34
elmot 1:d0dfbce63a89 35 // Used to avoid unnecessary frequency updates
elmot 1:d0dfbce63a89 36 _owner = this;
elmot 1:d0dfbce63a89 37 }
elmot 1:d0dfbce63a89 38
elmot 1:d0dfbce63a89 39 void I2C::frequency(int hz) {
elmot 1:d0dfbce63a89 40 lock();
elmot 1:d0dfbce63a89 41 _hz = hz;
elmot 1:d0dfbce63a89 42
elmot 1:d0dfbce63a89 43 // We want to update the frequency even if we are already the bus owners
elmot 1:d0dfbce63a89 44 i2c_frequency(&_i2c, _hz);
elmot 1:d0dfbce63a89 45
elmot 1:d0dfbce63a89 46 // Updating the frequency of the bus we become the owners of it
elmot 1:d0dfbce63a89 47 _owner = this;
elmot 1:d0dfbce63a89 48 unlock();
elmot 1:d0dfbce63a89 49 }
elmot 1:d0dfbce63a89 50
elmot 1:d0dfbce63a89 51 void I2C::aquire() {
elmot 1:d0dfbce63a89 52 lock();
elmot 1:d0dfbce63a89 53 if (_owner != this) {
elmot 1:d0dfbce63a89 54 i2c_frequency(&_i2c, _hz);
elmot 1:d0dfbce63a89 55 _owner = this;
elmot 1:d0dfbce63a89 56 }
elmot 1:d0dfbce63a89 57 unlock();
elmot 1:d0dfbce63a89 58 }
elmot 1:d0dfbce63a89 59
elmot 1:d0dfbce63a89 60 // write - Master Transmitter Mode
elmot 1:d0dfbce63a89 61 int I2C::write(int address, const char* data, int length, bool repeated) {
elmot 1:d0dfbce63a89 62 lock();
elmot 1:d0dfbce63a89 63 aquire();
elmot 1:d0dfbce63a89 64
elmot 1:d0dfbce63a89 65 int stop = (repeated) ? 0 : 1;
elmot 1:d0dfbce63a89 66 int written = i2c_write(&_i2c, address, data, length, stop);
elmot 1:d0dfbce63a89 67
elmot 1:d0dfbce63a89 68 unlock();
elmot 1:d0dfbce63a89 69 return length != written;
elmot 1:d0dfbce63a89 70 }
elmot 1:d0dfbce63a89 71
elmot 1:d0dfbce63a89 72 int I2C::write(int data) {
elmot 1:d0dfbce63a89 73 lock();
elmot 1:d0dfbce63a89 74 int ret = i2c_byte_write(&_i2c, data);
elmot 1:d0dfbce63a89 75 unlock();
elmot 1:d0dfbce63a89 76 return ret;
elmot 1:d0dfbce63a89 77 }
elmot 1:d0dfbce63a89 78
elmot 1:d0dfbce63a89 79 // read - Master Reciever Mode
elmot 1:d0dfbce63a89 80 int I2C::read(int address, char* data, int length, bool repeated) {
elmot 1:d0dfbce63a89 81 lock();
elmot 1:d0dfbce63a89 82 aquire();
elmot 1:d0dfbce63a89 83
elmot 1:d0dfbce63a89 84 int stop = (repeated) ? 0 : 1;
elmot 1:d0dfbce63a89 85 int read = i2c_read(&_i2c, address, data, length, stop);
elmot 1:d0dfbce63a89 86
elmot 1:d0dfbce63a89 87 unlock();
elmot 1:d0dfbce63a89 88 return length != read;
elmot 1:d0dfbce63a89 89 }
elmot 1:d0dfbce63a89 90
elmot 1:d0dfbce63a89 91 int I2C::read(int ack) {
elmot 1:d0dfbce63a89 92 lock();
elmot 1:d0dfbce63a89 93 int ret;
elmot 1:d0dfbce63a89 94 if (ack) {
elmot 1:d0dfbce63a89 95 ret = i2c_byte_read(&_i2c, 0);
elmot 1:d0dfbce63a89 96 } else {
elmot 1:d0dfbce63a89 97 ret = i2c_byte_read(&_i2c, 1);
elmot 1:d0dfbce63a89 98 }
elmot 1:d0dfbce63a89 99 unlock();
elmot 1:d0dfbce63a89 100 return ret;
elmot 1:d0dfbce63a89 101 }
elmot 1:d0dfbce63a89 102
elmot 1:d0dfbce63a89 103 void I2C::start(void) {
elmot 1:d0dfbce63a89 104 lock();
elmot 1:d0dfbce63a89 105 i2c_start(&_i2c);
elmot 1:d0dfbce63a89 106 unlock();
elmot 1:d0dfbce63a89 107 }
elmot 1:d0dfbce63a89 108
elmot 1:d0dfbce63a89 109 void I2C::stop(void) {
elmot 1:d0dfbce63a89 110 lock();
elmot 1:d0dfbce63a89 111 i2c_stop(&_i2c);
elmot 1:d0dfbce63a89 112 unlock();
elmot 1:d0dfbce63a89 113 }
elmot 1:d0dfbce63a89 114
elmot 1:d0dfbce63a89 115 void I2C::lock() {
elmot 1:d0dfbce63a89 116 _mutex->lock();
elmot 1:d0dfbce63a89 117 }
elmot 1:d0dfbce63a89 118
elmot 1:d0dfbce63a89 119 void I2C::unlock() {
elmot 1:d0dfbce63a89 120 _mutex->unlock();
elmot 1:d0dfbce63a89 121 }
elmot 1:d0dfbce63a89 122
elmot 1:d0dfbce63a89 123 #if DEVICE_I2C_ASYNCH
elmot 1:d0dfbce63a89 124
elmot 1:d0dfbce63a89 125 int I2C::transfer(int address, const char *tx_buffer, int tx_length, char *rx_buffer, int rx_length, const event_callback_t& callback, int event, bool repeated)
elmot 1:d0dfbce63a89 126 {
elmot 1:d0dfbce63a89 127 lock();
elmot 1:d0dfbce63a89 128 if (i2c_active(&_i2c)) {
elmot 1:d0dfbce63a89 129 unlock();
elmot 1:d0dfbce63a89 130 return -1; // transaction ongoing
elmot 1:d0dfbce63a89 131 }
elmot 1:d0dfbce63a89 132 aquire();
elmot 1:d0dfbce63a89 133
elmot 1:d0dfbce63a89 134 _callback = callback;
elmot 1:d0dfbce63a89 135 int stop = (repeated) ? 0 : 1;
elmot 1:d0dfbce63a89 136 _irq.callback(&I2C::irq_handler_asynch);
elmot 1:d0dfbce63a89 137 i2c_transfer_asynch(&_i2c, (void *)tx_buffer, tx_length, (void *)rx_buffer, rx_length, address, stop, _irq.entry(), event, _usage);
elmot 1:d0dfbce63a89 138 unlock();
elmot 1:d0dfbce63a89 139 return 0;
elmot 1:d0dfbce63a89 140 }
elmot 1:d0dfbce63a89 141
elmot 1:d0dfbce63a89 142 void I2C::abort_transfer(void)
elmot 1:d0dfbce63a89 143 {
elmot 1:d0dfbce63a89 144 lock();
elmot 1:d0dfbce63a89 145 i2c_abort_asynch(&_i2c);
elmot 1:d0dfbce63a89 146 unlock();
elmot 1:d0dfbce63a89 147 }
elmot 1:d0dfbce63a89 148
elmot 1:d0dfbce63a89 149 void I2C::irq_handler_asynch(void)
elmot 1:d0dfbce63a89 150 {
elmot 1:d0dfbce63a89 151 int event = i2c_irq_handler_asynch(&_i2c);
elmot 1:d0dfbce63a89 152 if (_callback && event) {
elmot 1:d0dfbce63a89 153 _callback.call(event);
elmot 1:d0dfbce63a89 154 }
elmot 1:d0dfbce63a89 155
elmot 1:d0dfbce63a89 156 }
elmot 1:d0dfbce63a89 157
elmot 1:d0dfbce63a89 158
elmot 1:d0dfbce63a89 159 #endif
elmot 1:d0dfbce63a89 160
elmot 1:d0dfbce63a89 161 } // namespace mbed
elmot 1:d0dfbce63a89 162
elmot 1:d0dfbce63a89 163 #endif