1 | /* |
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2 | * Generic I2C bus interface for RTEMS |
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3 | * |
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4 | * Copyright (C) 2000 OKTET Ltd., St.-Petersburg, Russia |
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5 | * Author: Victor V. Vengerov <vvv@oktet.ru> |
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6 | * |
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7 | * The license and distribution terms for this file may be |
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8 | * found in the file LICENSE in this distribution or at |
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9 | * |
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10 | * http://www.rtems.org/license/LICENSE. |
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11 | */ |
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12 | |
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13 | #ifndef __RTEMS__I2C_H__ |
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14 | #define __RTEMS__I2C_H__ |
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15 | |
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16 | #include <rtems.h> |
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17 | #include <bsp.h> |
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18 | /* This header file define the generic interface to i2c buses available in |
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19 | * system. This interface may be used by user applications or i2c-device |
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20 | * drivers (like RTC, NVRAM, etc). |
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21 | * |
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22 | * Functions i2c_initialize and i2c_transfer declared in this header usually |
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23 | * implemented in particular board support package. Usually this |
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24 | * implementation is a simple wrapper or multiplexor to I2C controller |
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25 | * driver which is available in system. It may be generic "software |
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26 | * controller" I2C driver which control SDA and SCL signals directly (if SDA |
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27 | * and SCL is general-purpose I/O pins), or driver for hardware I2C |
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28 | * controller (standalone or integrated with processors: MBus controller in |
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29 | * ColdFire processors, I2C controller in PowerQUICC and so on). |
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30 | * |
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31 | * i2c_transfer is a very generic low-level function. Higher-level function |
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32 | * i2c_write, i2c_read, i2c_wrrd, i2c_wbrd is defined here too. |
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33 | */ |
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34 | |
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35 | /* I2C Bus Number type */ |
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36 | typedef uint32_t i2c_bus_number; |
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37 | |
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38 | /* I2C device address */ |
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39 | typedef uint16_t i2c_address; |
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40 | |
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41 | /* I2C error codes generated during message transfer */ |
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42 | typedef enum i2c_message_status { |
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43 | I2C_SUCCESSFUL = 0, |
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44 | I2C_TIMEOUT, |
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45 | I2C_NO_DEVICE, |
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46 | I2C_ARBITRATION_LOST, |
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47 | I2C_NO_ACKNOWLEDGE, |
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48 | I2C_NO_DATA, |
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49 | I2C_RESOURCE_NOT_AVAILABLE |
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50 | } i2c_message_status; |
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51 | |
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52 | /* I2C Message */ |
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53 | typedef struct i2c_message { |
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54 | i2c_address addr; /* I2C slave device address */ |
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55 | uint16_t flags; /* message flags (see below) */ |
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56 | i2c_message_status status; /* message transfer status code */ |
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57 | uint16_t len; /* Number of bytes to read or write */ |
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58 | uint8_t *buf; /* pointer to data array */ |
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59 | } i2c_message; |
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60 | |
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61 | /* I2C message flag */ |
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62 | #define I2C_MSG_ADDR_10 (0x01) /* 10-bit address */ |
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63 | #define I2C_MSG_WR (0x02) /* transfer direction for this message |
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64 | from master to slave */ |
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65 | #define I2C_MSG_ERRSKIP (0x04) /* Skip message if last transfered message |
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66 | is failed */ |
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67 | /* Type for function which is called when transfer over I2C bus is finished */ |
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68 | typedef void (*i2c_transfer_done) (void *arg); |
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69 | |
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70 | /* i2c_initialize -- |
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71 | * I2C driver initialization. This function usually called on device |
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72 | * driver initialization state, before initialization task. All I2C |
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73 | * buses are initialized; reasonable slow data transfer rate is |
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74 | * selected for each bus. |
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75 | * |
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76 | * PARAMETERS: |
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77 | * major - I2C device major number |
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78 | * minor - I2C device minor number |
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79 | * arg - RTEMS driver initialization argument |
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80 | * |
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81 | * RETURNS: |
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82 | * RTEMS status code |
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83 | */ |
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84 | rtems_device_driver |
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85 | i2c_initialize(rtems_device_major_number major, |
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86 | rtems_device_minor_number minor, |
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87 | void *arg); |
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88 | |
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89 | /* i2c_select_clock_rate -- |
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90 | * select I2C bus clock rate for specified bus. Some bus controller do not |
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91 | * allow to select arbitrary clock rate; in this case nearest possible |
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92 | * slower clock rate is selected. |
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93 | * |
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94 | * PARAMETERS: |
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95 | * bus - I2C bus number |
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96 | * bps - data transfer rate for this bytes in bits per second |
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97 | * |
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98 | * RETURNS: |
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99 | * RTEMS_SUCCESSFUL, if operation performed successfully, |
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100 | * RTEMS_INVALID_NUMBER, if wrong bus number is specified, |
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101 | * RTEMS_UNSATISFIED, if bus do not support data transfer rate selection |
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102 | * or specified data transfer rate could not be used. |
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103 | */ |
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104 | rtems_status_code |
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105 | i2c_select_clock_rate(i2c_bus_number bus, int bps); |
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106 | |
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107 | /* i2c_transfer -- |
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108 | * Initiate multiple-messages transfer over specified I2C bus or |
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109 | * put request into queue if bus or some other resource is busy. (This |
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110 | * is non-blocking function). |
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111 | * |
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112 | * PARAMETERS: |
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113 | * bus - I2C bus number |
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114 | * nmsg - number of messages |
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115 | * msg - pointer to messages array |
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116 | * done - function which is called when transfer is finished |
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117 | * done_arg_ptr - arbitrary argument ptr passed to done funciton |
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118 | * |
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119 | * RETURNS: |
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120 | * RTEMS_SUCCESSFUL if transfer initiated successfully, or error |
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121 | * code if something failed. |
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122 | */ |
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123 | rtems_status_code |
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124 | i2c_transfer(i2c_bus_number bus, int nmsg, i2c_message *msg, |
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125 | i2c_transfer_done done, void * done_arg_ptr); |
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126 | |
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127 | /* i2c_transfer_wait -- |
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128 | * Initiate I2C bus transfer and block until this transfer will be |
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129 | * finished. This function wait the semaphore if system in |
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130 | * SYSTEM_STATE_UP state, or poll done flag in other states. |
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131 | * |
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132 | * PARAMETERS: |
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133 | * bus - I2C bus number |
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134 | * msg - pointer to transfer messages array |
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135 | * nmsg - number of messages in transfer |
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136 | * |
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137 | * RETURNS: |
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138 | * I2C_SUCCESSFUL, if transfer finished successfully, |
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139 | * I2C_RESOURCE_NOT_AVAILABLE, if semaphore operations has failed, |
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140 | * value of status field of first error-finished message in transfer, |
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141 | * if something wrong. |
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142 | */ |
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143 | i2c_message_status |
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144 | i2c_transfer_wait(i2c_bus_number bus, i2c_message *msg, int nmsg); |
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145 | |
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146 | /* i2c_poll -- |
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147 | * Poll I2C bus controller for events and hanle it. This function is |
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148 | * used when I2C driver operates in poll-driven mode. |
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149 | * |
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150 | * PARAMETERS: |
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151 | * bus - bus number to be polled |
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152 | * |
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153 | * RETURNS: |
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154 | * none |
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155 | */ |
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156 | void |
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157 | i2c_poll(i2c_bus_number bus); |
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158 | |
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159 | /* i2c_write -- |
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160 | * Send single message over specified I2C bus to addressed device and |
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161 | * wait while transfer is finished. |
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162 | * |
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163 | * PARAMETERS: |
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164 | * bus - I2C bus number |
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165 | * addr - address of I2C device |
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166 | * buf - data to be sent to device |
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167 | * size - data buffer size |
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168 | * |
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169 | * RETURNS: |
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170 | * transfer status |
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171 | */ |
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172 | i2c_message_status |
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173 | i2c_write(i2c_bus_number bus, i2c_address addr, void *buf, int size); |
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174 | |
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175 | /* i2c_wrbyte -- |
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176 | * Send single one-byte long message over specified I2C bus to |
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177 | * addressed device and wait while transfer is finished. |
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178 | * |
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179 | * PARAMETERS: |
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180 | * bus - I2C bus number |
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181 | * addr - address of I2C device |
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182 | * cmd - byte message to be sent to device |
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183 | * |
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184 | * RETURNS: |
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185 | * transfer status |
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186 | */ |
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187 | i2c_message_status |
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188 | i2c_wrbyte(i2c_bus_number bus, i2c_address addr, uint8_t cmd); |
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189 | |
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190 | /* i2c_read -- |
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191 | * receive single message over specified I2C bus from addressed device. |
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192 | * This call will wait while transfer is finished. |
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193 | * |
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194 | * PARAMETERS: |
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195 | * bus - I2C bus number |
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196 | * addr - address of I2C device |
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197 | * buf - buffer for received message |
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198 | * size - receive buffer size |
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199 | * |
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200 | * RETURNS: |
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201 | * transfer status |
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202 | */ |
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203 | i2c_message_status |
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204 | i2c_read(i2c_bus_number bus, i2c_address addr, void *buf, int size); |
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205 | |
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206 | /* i2c_wrrd -- |
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207 | * Send message over I2C bus to specified device and receive message |
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208 | * from the same device during single transfer. |
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209 | * |
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210 | * PARAMETERS: |
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211 | * bus - I2C bus number |
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212 | * addr - address of I2C device |
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213 | * bufw - data to be sent to device |
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214 | * sizew - send data buffer size |
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215 | * bufr - buffer for received message |
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216 | * sizer - receive buffer size |
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217 | * |
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218 | * RETURNS: |
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219 | * transfer status |
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220 | */ |
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221 | i2c_message_status |
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222 | i2c_wrrd(i2c_bus_number bus, i2c_address addr, void *bufw, int sizew, |
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223 | void *bufr, int sizer); |
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224 | |
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225 | /* i2c_wbrd -- |
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226 | * Send one-byte message over I2C bus to specified device and receive |
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227 | * message from the same device during single transfer. |
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228 | * |
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229 | * PARAMETERS: |
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230 | * bus - I2C bus number |
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231 | * addr - address of I2C device |
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232 | * cmd - one-byte message to be sent over I2C bus |
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233 | * bufr - buffer for received message |
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234 | * sizer - receive buffer size |
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235 | * |
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236 | * RETURNS: |
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237 | * transfer status |
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238 | */ |
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239 | i2c_message_status |
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240 | i2c_wbrd(i2c_bus_number bus, i2c_address addr, uint8_t cmd, |
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241 | void *bufr, int sizer); |
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242 | |
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243 | #endif |
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