1 | /* $Id$ */ |
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2 | |
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3 | /* Trivial i2c driver for reading "2-byte eeproms". |
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4 | * On 'open' the read-pointer is reset to 0, subsequent |
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5 | * read operations slurp data from there... |
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6 | */ |
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7 | |
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8 | /* |
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9 | * Authorship |
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10 | * ---------- |
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11 | * This software was created by |
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12 | * Till Straumann <strauman@slac.stanford.edu>, 2005, |
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13 | * Stanford Linear Accelerator Center, Stanford University. |
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14 | * |
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15 | * Acknowledgement of sponsorship |
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16 | * ------------------------------ |
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17 | * This software was produced by |
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18 | * the Stanford Linear Accelerator Center, Stanford University, |
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19 | * under Contract DE-AC03-76SFO0515 with the Department of Energy. |
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20 | * |
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21 | * Government disclaimer of liability |
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22 | * ---------------------------------- |
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23 | * Neither the United States nor the United States Department of Energy, |
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24 | * nor any of their employees, makes any warranty, express or implied, or |
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25 | * assumes any legal liability or responsibility for the accuracy, |
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26 | * completeness, or usefulness of any data, apparatus, product, or process |
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27 | * disclosed, or represents that its use would not infringe privately owned |
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28 | * rights. |
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29 | * |
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30 | * Stanford disclaimer of liability |
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31 | * -------------------------------- |
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32 | * Stanford University makes no representations or warranties, express or |
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33 | * implied, nor assumes any liability for the use of this software. |
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34 | * |
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35 | * Stanford disclaimer of copyright |
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36 | * -------------------------------- |
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37 | * Stanford University, owner of the copyright, hereby disclaims its |
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38 | * copyright and all other rights in this software. Hence, anyone may |
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39 | * freely use it for any purpose without restriction. |
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40 | * |
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41 | * Maintenance of notices |
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42 | * ---------------------- |
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43 | * In the interest of clarity regarding the origin and status of this |
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44 | * SLAC software, this and all the preceding Stanford University notices |
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45 | * are to remain affixed to any copy or derivative of this software made |
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46 | * or distributed by the recipient and are to be affixed to any copy of |
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47 | * software made or distributed by the recipient that contains a copy or |
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48 | * derivative of this software. |
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49 | * |
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50 | * ------------------ SLAC Software Notices, Set 4 OTT.002a, 2004 FEB 03 |
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51 | */ |
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52 | |
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53 | |
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54 | #include <rtems.h> |
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55 | #include <rtems/libi2c.h> |
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56 | |
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57 | #include <libchip/i2c-2b-eeprom.h> |
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58 | #include <rtems/libio.h> |
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59 | |
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60 | #define EEPROM_PG_SZ 32 |
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61 | #define ALGN(x) (((uint32_t)(x) + EEPROM_PG_SZ) & ~(EEPROM_PG_SZ-1)) |
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62 | |
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63 | static rtems_status_code |
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64 | send_file_ptr (rtems_device_minor_number minor, unsigned pos, int tout) |
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65 | { |
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66 | int sc; |
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67 | unsigned char bytes[2]; |
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68 | |
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69 | bytes[0] = (pos >> 8) & 0xff; |
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70 | bytes[1] = (pos) & 0xff; |
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71 | |
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72 | /* poll addressing the next page; if 'tout' is <=0 we only try once |
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73 | * and return the status. If 'tout' is positive, we try 'tout' times |
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74 | * and return RTEMS_TIMEOUT if it didnt work |
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75 | */ |
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76 | while ((sc = rtems_libi2c_start_write_bytes (minor, bytes, 2)) < 0) { |
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77 | if (--tout <= 0) |
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78 | return tout ? -sc : RTEMS_TIMEOUT; |
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79 | rtems_task_wake_after (1); |
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80 | } |
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81 | return RTEMS_SUCCESSFUL; |
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82 | } |
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83 | |
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84 | static rtems_status_code |
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85 | i2c_2b_eeprom_write (rtems_device_major_number major, |
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86 | rtems_device_minor_number minor, void *arg) |
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87 | { |
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88 | rtems_libio_rw_args_t *rwargs = arg; |
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89 | unsigned off = rwargs->offset; |
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90 | int cnt = rwargs->count; |
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91 | unsigned char *buf = (unsigned char *)rwargs->buffer; |
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92 | int sc; |
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93 | unsigned end; |
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94 | int l; |
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95 | |
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96 | if (cnt <= 0) |
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97 | return RTEMS_SUCCESSFUL; |
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98 | |
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99 | if ((sc = send_file_ptr (minor, off, 0))) |
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100 | return sc; |
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101 | |
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102 | do { |
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103 | /* write up to next page boundary */ |
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104 | end = ALGN (off); |
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105 | l = end - off; |
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106 | if (l > cnt) |
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107 | l = cnt; |
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108 | |
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109 | sc = rtems_libi2c_write_bytes (minor, buf, l); |
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110 | if (sc < 0) |
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111 | return -sc; |
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112 | |
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113 | sc = rtems_libi2c_send_stop (minor); |
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114 | if (sc) |
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115 | return sc; |
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116 | |
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117 | rwargs->bytes_moved += l; |
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118 | |
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119 | buf += l; |
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120 | cnt -= l; |
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121 | off += l; |
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122 | |
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123 | /* poll addressing the next page */ |
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124 | if ((sc = send_file_ptr (minor, off, 100))) |
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125 | return sc; |
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126 | |
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127 | } while (cnt > 0); |
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128 | |
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129 | return rtems_libi2c_send_stop (minor); |
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130 | } |
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131 | |
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132 | static rtems_status_code |
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133 | i2c_2b_eeprom_read (rtems_device_major_number major, |
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134 | rtems_device_minor_number minor, void *arg) |
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135 | { |
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136 | int sc; |
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137 | rtems_libio_rw_args_t *rwargs = arg; |
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138 | |
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139 | if (RTEMS_SUCCESSFUL != (sc = send_file_ptr (minor, rwargs->offset, 0))) |
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140 | return -sc; |
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141 | |
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142 | sc = rtems_libi2c_start_read_bytes( |
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143 | minor, |
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144 | (unsigned char *)rwargs->buffer, |
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145 | rwargs->count |
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146 | ); |
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147 | |
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148 | if (sc < 0) { |
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149 | rwargs->bytes_moved = 0; |
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150 | return -sc; |
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151 | } |
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152 | rwargs->bytes_moved = sc; |
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153 | |
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154 | return rtems_libi2c_send_stop (minor); |
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155 | } |
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156 | |
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157 | static rtems_driver_address_table myops = { |
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158 | read_entry: i2c_2b_eeprom_read, |
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159 | write_entry: i2c_2b_eeprom_write, |
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160 | }; |
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161 | |
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162 | static rtems_libi2c_drv_t my_drv_tbl = { |
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163 | ops: &myops, |
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164 | size: sizeof (my_drv_tbl), |
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165 | }; |
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166 | |
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167 | /* provide a second table for R/O access */ |
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168 | static rtems_driver_address_table my_ro_ops = { |
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169 | read_entry: i2c_2b_eeprom_read, |
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170 | }; |
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171 | |
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172 | static rtems_libi2c_drv_t my_ro_drv_tbl = { |
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173 | ops: &my_ro_ops, |
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174 | size: sizeof (my_ro_drv_tbl), |
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175 | }; |
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176 | |
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177 | |
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178 | rtems_libi2c_drv_t *i2c_2b_eeprom_driver_descriptor = &my_drv_tbl; |
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179 | rtems_libi2c_drv_t *i2c_2b_eeprom_ro_driver_descriptor = &my_ro_drv_tbl; |
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