Merge pull request #764 from pieterdepiet/LinuxI2CDev

Support for Linux /dev/i2c-%u

Author: jrowberg

LinuxI2CDev/I2Cdev/I2Cdev.cpp

@@ -0,0 +1,391 @@
+// I2Cdev library collection - Main I2C device class
+// Abstracts bit and byte I2C R/W functions into a convenient class
+// 2013-06-05 by Jeff Rowberg <jeff@rowberg.net>
+//
+// Changelog:
+//      2021-09-28 - allow custom Wire object as transaction function argument
+//      2020-01-20 - hardija : complete support for Teensy 3.x
+//      2015-10-30 - simondlevy : support i2c_t3 for Teensy3.1
+//      2013-05-06 - add Francesco Ferrara's Fastwire v0.24 implementation with small modifications
+//      2013-05-05 - fix issue with writing bit values to words (Sasquatch/Farzanegan)
+//      2012-06-09 - fix major issue with reading > 32 bytes at a time with Arduino Wire
+//                 - add compiler warnings when using outdated or IDE or limited I2Cdev implementation
+//      2011-11-01 - fix write*Bits mask calculation (thanks sasquatch @ Arduino forums)
+//      2011-10-03 - added automatic Arduino version detection for ease of use
+//      2011-10-02 - added Gene Knight's NBWire TwoWire class implementation with small modifications
+//      2011-08-31 - added support for Arduino 1.0 Wire library (methods are different from 0.x)
+//      2011-08-03 - added optional timeout parameter to read* methods to easily change from default
+//      2011-08-02 - added support for 16-bit registers
+//                 - fixed incorrect Doxygen comments on some methods
+//                 - added timeout value for read operations (thanks mem @ Arduino forums)
+//      2011-07-30 - changed read/write function structures to return success or byte counts
+//                 - made all methods static for multi-device memory savings
+//      2011-07-28 - initial release
+
+/* ============================================
+I2Cdev device library code is placed under the MIT license
+Copyright (c) 2013 Jeff Rowberg
+
+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 "I2Cdev.h"
+
+#include <fcntl.h>
+#include <unistd.h>
+#include <errno.h>
+#include <string.h>
+#include <stdio.h>
+#include <sys/ioctl.h>
+#include <linux/i2c-dev.h>
+
+static const char* i2cDev = NULL;
+/** Default constructor.
+ */
+I2Cdev::I2Cdev() {
+}
+
+void I2Cdev::initialize(const char* devPath) {
+	i2cDev = devPath;
+}
+/** Read a single bit from an 8-bit device register.
+ * @param devAddr I2C slave device address
+ * @param regAddr Register regAddr to read from
+ * @param bitNum Bit position to read (0-7)
+ * @param data Container for single bit value
+ * @param timeout Optional read timeout in milliseconds (0 to disable, leave off to use default class value in I2Cdev::readTimeout)
+ * @return Status of read operation (true = success)
+ */
+int8_t I2Cdev::readBit(uint8_t devAddr, uint8_t regAddr, uint8_t bitNum, uint8_t *data, uint16_t timeout) {
+    uint8_t b;
+    uint8_t count = readByte(devAddr, regAddr, &b, timeout);
+    *data = b & (1 << bitNum);
+    return count;
+}
+
+/** Read a single bit from a 16-bit device register.
+ * @param devAddr I2C slave device address
+ * @param regAddr Register regAddr to read from
+ * @param bitNum Bit position to read (0-15)
+ * @param data Container for single bit value
+ * @param timeout Optional read timeout in milliseconds (0 to disable, leave off to use default class value in I2Cdev::readTimeout)
+ * @return Status of read operation (true = success)
+ */
+int8_t I2Cdev::readBitW(uint8_t devAddr, uint8_t regAddr, uint8_t bitNum, uint16_t *data, uint16_t timeout) {
+    uint16_t b;
+    uint8_t count = readWord(devAddr, regAddr, &b, timeout);
+    *data = b & (1 << bitNum);
+    return count;
+}
+
+/** Read multiple bits from an 8-bit device register.
+ * @param devAddr I2C slave device address
+ * @param regAddr Register regAddr to read from
+ * @param bitStart First bit position to read (0-7)
+ * @param length Number of bits to read (not more than 8)
+ * @param data Container for right-aligned value (i.e. '101' read from any bitStart position will equal 0x05)
+ * @param timeout Optional read timeout in milliseconds (0 to disable, leave off to use default class value in I2Cdev::readTimeout)
+ * @return Status of read operation (true = success)
+ */
+int8_t I2Cdev::readBits(uint8_t devAddr, uint8_t regAddr, uint8_t bitStart, uint8_t length, uint8_t *data, uint16_t timeout) {
+    // 01101001 read byte
+    // 76543210 bit numbers
+    //    xxx   args: bitStart=4, length=3
+    //    010   masked
+    //   -> 010 shifted
+    uint8_t count, b;
+    if ((count = readByte(devAddr, regAddr, &b, timeout)) != 0) {
+        uint8_t mask = ((1 << length) - 1) << (bitStart - length + 1);
+        b &= mask;
+        b >>= (bitStart - length + 1);
+        *data = b;
+    }
+    return count;
+}
+
+/** Read multiple bits from a 16-bit device register.
+ * @param devAddr I2C slave device address
+ * @param regAddr Register regAddr to read from
+ * @param bitStart First bit position to read (0-15)
+ * @param length Number of bits to read (not more than 16)
+ * @param data Container for right-aligned value (i.e. '101' read from any bitStart position will equal 0x05)
+ * @param timeout Optional read timeout in milliseconds (0 to disable, leave off to use default class value in I2Cdev::readTimeout)
+ * @return Status of read operation (1 = success, 0 = failure, -1 = timeout)
+ */
+int8_t I2Cdev::readBitsW(uint8_t devAddr, uint8_t regAddr, uint8_t bitStart, uint8_t length, uint16_t *data, uint16_t timeout) {
+    // 1101011001101001 read byte
+    // fedcba9876543210 bit numbers
+    //    xxx           args: bitStart=12, length=3
+    //    010           masked
+    //           -> 010 shifted
+    uint8_t count;
+    uint16_t w;
+    if ((count = readWord(devAddr, regAddr, &w, timeout)) != 0) {
+        uint16_t mask = ((1 << length) - 1) << (bitStart - length + 1);
+        w &= mask;
+        w >>= (bitStart - length + 1);
+        *data = w;
+    }
+    return count;
+}
+
+/** Read single byte from an 8-bit device register.
+ * @param devAddr I2C slave device address
+ * @param regAddr Register regAddr to read from
+ * @param data Container for byte value read from device
+ * @param timeout Optional read timeout in milliseconds (0 to disable, leave off to use default class value in I2Cdev::readTimeout)
+ * @return Status of read operation (true = success)
+ */
+int8_t I2Cdev::readByte(uint8_t devAddr, uint8_t regAddr, uint8_t *data, uint16_t timeout) {
+    return readBytes(devAddr, regAddr, 1, data, timeout);
+}
+
+/** Read single word from a 16-bit device register.
+ * @param devAddr I2C slave device address
+ * @param regAddr Register regAddr to read from
+ * @param data Container for word value read from device
+ * @param timeout Optional read timeout in milliseconds (0 to disable, leave off to use default class value in I2Cdev::readTimeout)
+ * @return Status of read operation (true = success)
+ */
+int8_t I2Cdev::readWord(uint8_t devAddr, uint8_t regAddr, uint16_t *data, uint16_t timeout) {
+    return readWords(devAddr, regAddr, 1, data, timeout);
+}
+
+/** Read multiple bytes from an 8-bit device register.
+ * @param devAddr I2C slave device address
+ * @param regAddr First register regAddr to read from
+ * @param length Number of bytes to read
+ * @param data Buffer to store read data in
+ * @param timeout Optional read timeout in milliseconds (0 to disable, leave off to use default class value in I2Cdev::readTimeout)
+ * @return Number of bytes read (-1 indicates failure)
+ */
+int8_t I2Cdev::readBytes(uint8_t devAddr, uint8_t regAddr, uint8_t length, uint8_t *data, uint16_t timeout) {
+    int fd = open(i2cDev, O_RDWR);
+    if (fd < 0) {
+        fprintf(stderr, "Failed to open i2c device %s: %s\n", i2cDev, strerror(errno));
+        return -1;
+    }
+    if (ioctl(fd, I2C_SLAVE, (unsigned long) devAddr) < 0) {
+        fprintf(stderr, "Failed to set i2c address to %u: %s\n", devAddr, strerror(errno));
+        close(fd);
+        return -1;
+    }
+    if (timeout != 0 && ioctl(fd, I2C_TIMEOUT, (unsigned long) timeout / 100) < 0) {
+        fprintf(stderr, "Failed to set i2c timeout: %s\n", strerror(errno));
+    }
+    if (write(fd, &regAddr, 1) != 1) {
+        fprintf(stderr, "Failed to write reg: %s\n", strerror(errno));
+    }
+    if (read(fd, data, length) != length) {
+        fprintf(stderr, "Failed to read reg: %s\n", strerror(errno));
+        close(fd);
+        return -1;
+    }
+    close(fd);
+    return length;
+}
+
+/** Read multiple words from a 16-bit device register.
+ * @param devAddr I2C slave device address
+ * @param regAddr First register regAddr to read from
+ * @param length Number of words to read
+ * @param data Buffer to store read data in
+ * @param timeout Optional read timeout in milliseconds (0 to disable, leave off to use default class value in I2Cdev::readTimeout)
+ * @return Number of words read (-1 indicates failure)
+ */
+int8_t I2Cdev::readWords(uint8_t devAddr, uint8_t regAddr, uint8_t length, uint16_t *data, uint16_t timeout) {
+    uint8_t buff[length * 2];
+
+    if (readBytes(devAddr, regAddr, length * 2, buff, timeout) > 0)
+    {
+        for (int i = 0; i < length; i++)
+        {
+            data[i] = (buff[i * 2] << 8) | buff[i * 2 + 1];
+        }
+        return length;
+    }
+
+    return -1;
+}
+
+/** write a single bit in an 8-bit device register.
+ * @param devAddr I2C slave device address
+ * @param regAddr Register regAddr to write to
+ * @param bitNum Bit position to write (0-7)
+ * @param value New bit value to write
+ * @return Status of operation (true = success)
+ */
+bool I2Cdev::writeBit(uint8_t devAddr, uint8_t regAddr, uint8_t bitNum, uint8_t data) {
+    uint8_t b;
+    readByte(devAddr, regAddr, &b, I2Cdev::readTimeout);
+    b = (data != 0) ? (b | (1 << bitNum)) : (b & ~(1 << bitNum));
+    return writeByte(devAddr, regAddr, b);
+}
+
+/** write a single bit in a 16-bit device register.
+ * @param devAddr I2C slave device address
+ * @param regAddr Register regAddr to write to
+ * @param bitNum Bit position to write (0-15)
+ * @param value New bit value to write
+ * @return Status of operation (true = success)
+ */
+bool I2Cdev::writeBitW(uint8_t devAddr, uint8_t regAddr, uint8_t bitNum, uint16_t data) {
+    uint16_t w;
+    readWord(devAddr, regAddr, &w, I2Cdev::readTimeout);
+    w = (data != 0) ? (w | (1 << bitNum)) : (w & ~(1 << bitNum));
+    return writeWord(devAddr, regAddr, w);
+}
+
+/** Write multiple bits in an 8-bit device register.
+ * @param devAddr I2C slave device address
+ * @param regAddr Register regAddr to write to
+ * @param bitStart First bit position to write (0-7)
+ * @param length Number of bits to write (not more than 8)
+ * @param data Right-aligned value to write
+ * @return Status of operation (true = success)
+ */
+bool I2Cdev::writeBits(uint8_t devAddr, uint8_t regAddr, uint8_t bitStart, uint8_t length, uint8_t data) {
+    //      010 value to write
+    // 76543210 bit numbers
+    //    xxx   args: bitStart=4, length=3
+    // 00011100 mask byte
+    // 10101111 original value (sample)
+    // 10100011 original & ~mask
+    // 10101011 masked | value
+    uint8_t b;
+    if (readByte(devAddr, regAddr, &b, I2Cdev::readTimeout) != 0) {
+        uint8_t mask = ((1 << length) - 1) << (bitStart - length + 1);
+        data <<= (bitStart - length + 1); // shift data into correct position
+        data &= mask; // zero all non-important bits in data
+        b &= ~(mask); // zero all important bits in existing byte
+        b |= data; // combine data with existing byte
+        return writeByte(devAddr, regAddr, b);
+    } else {
+        return false;
+    }
+}
+
+/** Write multiple bits in a 16-bit device register.
+ * @param devAddr I2C slave device address
+ * @param regAddr Register regAddr to write to
+ * @param bitStart First bit position to write (0-15)
+ * @param length Number of bits to write (not more than 16)
+ * @param data Right-aligned value to write
+ * @return Status of operation (true = success)
+ */
+bool I2Cdev::writeBitsW(uint8_t devAddr, uint8_t regAddr, uint8_t bitStart, uint8_t length, uint16_t data) {
+    //              010 value to write
+    // fedcba9876543210 bit numbers
+    //    xxx           args: bitStart=12, length=3
+    // 0001110000000000 mask word
+    // 1010111110010110 original value (sample)
+    // 1010001110010110 original & ~mask
+    // 1010101110010110 masked | value
+    uint16_t w;
+    if (readWord(devAddr, regAddr, &w, I2Cdev::readTimeout) != 0) {
+        uint16_t mask = ((1 << length) - 1) << (bitStart - length + 1);
+        data <<= (bitStart - length + 1); // shift data into correct position
+        data &= mask; // zero all non-important bits in data
+        w &= ~(mask); // zero all important bits in existing word
+        w |= data; // combine data with existing word
+        return writeWord(devAddr, regAddr, w);
+    } else {
+        return false;
+    }
+}
+
+/** Write single byte to an 8-bit device register.
+ * @param devAddr I2C slave device address
+ * @param regAddr Register address to write to
+ * @param data New byte value to write
+ * @return Status of operation (true = success)
+ */
+bool I2Cdev::writeByte(uint8_t devAddr, uint8_t regAddr, uint8_t data) {
+    return writeBytes(devAddr, regAddr, 1, &data);
+}
+
+/** Write single word to a 16-bit device register.
+ * @param devAddr I2C slave device address
+ * @param regAddr Register address to write to
+ * @param data New word value to write
+ * @return Status of operation (true = success)
+ */
+bool I2Cdev::writeWord(uint8_t devAddr, uint8_t regAddr, uint16_t data) {
+    return writeWords(devAddr, regAddr, 1, &data);
+}
+
+/** Write multiple bytes to an 8-bit device register.
+ * @param devAddr I2C slave device address
+ * @param regAddr First register address to write to
+ * @param length Number of bytes to write
+ * @param data Buffer to copy new data from
+ * @return Status of operation (true = success)
+ */
+bool I2Cdev::writeBytes(uint8_t devAddr, uint8_t regAddr, uint8_t length, uint8_t* data) {
+    int fd = open(i2cDev, O_RDWR);
+    if (fd < 0) {
+        fprintf(stderr, "Failed to open i2c device %s: %s\n", i2cDev, strerror(errno));
+        return -1;
+    }
+    if (ioctl(fd, I2C_SLAVE, (unsigned long) devAddr) < 0) {
+        fprintf(stderr, "Failed to set i2c address to %u: %s\n", devAddr, strerror(errno));
+        close(fd);
+        return -1;
+    }
+    uint16_t buff_length = length + 1;
+    uint8_t buff[buff_length];
+    buff[0] = regAddr;
+
+    memcpy(&buff[1], data, length);
+
+    if (write(fd, buff, buff_length) != buff_length)
+    {
+        fprintf(stderr, "Failed to write reg: %s\n", strerror(errno));
+        close(fd);
+        return false;
+    }
+    close(fd);
+    return true;
+}
+
+/** Write multiple words to a 16-bit device register.
+ * @param devAddr I2C slave device address
+ * @param regAddr First register address to write to
+ * @param length Number of words to write
+ * @param data Buffer to copy new data from
+ * @return Status of operation (true = success)
+ */
+bool I2Cdev::writeWords(uint8_t devAddr, uint8_t regAddr, uint8_t length, uint16_t* data) {
+    uint8_t buff[length * 2];
+
+    for (int i = 0; i < length; i++)
+    {
+        buff[2 * i] = (uint8_t)(data[i] >> 8);     //MSByte
+        buff[1 + 2 * i] = (uint8_t)(data[i] >> 0); //LSByte
+    }
+
+    return writeBytes(devAddr, regAddr, length * 2, buff);
+}
+
+/** Default timeout value for read operations.
+ * Set this to 0 to disable timeout detection.
+ */
+uint16_t I2Cdev::readTimeout = I2CDEV_DEFAULT_READ_TIMEOUT;
+