| 1 | /******************************************************************* |
| 2 | * |
| 3 | * Copyright (c) 2007 by Silicon Motion, Inc. (SMI) |
| 4 | * |
| 5 | * All rights are reserved. Reproduction or in part is prohibited |
| 6 | * without the written consent of the copyright owner. |
| 7 | * |
| 8 | * swi2c.c --- SM750/SM718 DDK |
| 9 | * This file contains the source code for I2C using software |
| 10 | * implementation. |
| 11 | * |
| 12 | *******************************************************************/ |
| 13 | #include "ddk750_help.h" |
| 14 | #include "ddk750_reg.h" |
| 15 | #include "ddk750_swi2c.h" |
| 16 | #include "ddk750_power.h" |
| 17 | |
| 18 | |
| 19 | /******************************************************************* |
| 20 | * I2C Software Master Driver: |
| 21 | * =========================== |
| 22 | * Each i2c cycle is split into 4 sections. Each of these section marks |
| 23 | * a point in time where the SCL or SDA may be changed. |
| 24 | * |
| 25 | * 1 Cycle == | Section I. | Section 2. | Section 3. | Section 4. | |
| 26 | * +-------------+-------------+-------------+-------------+ |
| 27 | * | SCL set LOW |SCL no change| SCL set HIGH|SCL no change| |
| 28 | * |
| 29 | * ____________ _____________ |
| 30 | * SCL == XXXX _____________ ____________ / |
| 31 | * |
| 32 | * I.e. the SCL may only be changed in section 1. and section 3. while |
| 33 | * the SDA may only be changed in section 2. and section 4. The table |
| 34 | * below gives the changes for these 2 lines in the varios sections. |
| 35 | * |
| 36 | * Section changes Table: |
| 37 | * ====================== |
| 38 | * blank = no change, L = set bit LOW, H = set bit HIGH |
| 39 | * |
| 40 | * | 1.| 2.| 3.| 4.| |
| 41 | * ---------------+---+---+---+---+ |
| 42 | * Tx Start SDA | | H | | L | |
| 43 | * SCL | L | | H | | |
| 44 | * ---------------+---+---+---+---+ |
| 45 | * Tx Stop SDA | | L | | H | |
| 46 | * SCL | L | | H | | |
| 47 | * ---------------+---+---+---+---+ |
| 48 | * Tx bit H SDA | | H | | | |
| 49 | * SCL | L | | H | | |
| 50 | * ---------------+---+---+---+---+ |
| 51 | * Tx bit L SDA | | L | | | |
| 52 | * SCL | L | | H | | |
| 53 | * ---------------+---+---+---+---+ |
| 54 | * |
| 55 | ******************************************************************/ |
| 56 | |
| 57 | /* GPIO pins used for this I2C. It ranges from 0 to 63. */ |
| 58 | static unsigned char g_i2cClockGPIO = DEFAULT_I2C_SCL; |
| 59 | static unsigned char g_i2cDataGPIO = DEFAULT_I2C_SDA; |
| 60 | |
| 61 | /* |
| 62 | * Below is the variable declaration for the GPIO pin register usage |
| 63 | * for the i2c Clock and i2c Data. |
| 64 | * |
| 65 | * Note: |
| 66 | * Notice that the GPIO usage for the i2c clock and i2c Data are |
| 67 | * separated. This is to make this code flexible enough when |
| 68 | * two separate GPIO pins for the clock and data are located |
| 69 | * in two different GPIO register set (worst case). |
| 70 | */ |
| 71 | |
| 72 | /* i2c Clock GPIO Register usage */ |
| 73 | static unsigned long g_i2cClkGPIOMuxReg = GPIO_MUX; |
| 74 | static unsigned long g_i2cClkGPIODataReg = GPIO_DATA; |
| 75 | static unsigned long g_i2cClkGPIODataDirReg = GPIO_DATA_DIRECTION; |
| 76 | |
| 77 | /* i2c Data GPIO Register usage */ |
| 78 | static unsigned long g_i2cDataGPIOMuxReg = GPIO_MUX; |
| 79 | static unsigned long g_i2cDataGPIODataReg = GPIO_DATA; |
| 80 | static unsigned long g_i2cDataGPIODataDirReg = GPIO_DATA_DIRECTION; |
| 81 | |
| 82 | /* |
| 83 | * This function puts a delay between command |
| 84 | */ |
| 85 | static void swI2CWait(void) |
| 86 | { |
| 87 | /* find a bug: |
| 88 | * peekIO method works well before suspend/resume |
| 89 | * but after suspend, peekIO(0x3ce,0x61) & 0x10 |
| 90 | * always be non-zero,which makes the while loop |
| 91 | * never finish. |
| 92 | * use non-ultimate for loop below is safe |
| 93 | * */ |
| 94 | #if 0 |
| 95 | /* Change wait algorithm to use PCI bus clock, |
| 96 | it's more reliable than counter loop .. |
| 97 | write 0x61 to 0x3ce and read from 0x3cf |
| 98 | */ |
| 99 | while(peekIO(0x3ce, 0x61) & 0x10); |
| 100 | #else |
| 101 | int i, Temp; |
| 102 | |
| 103 | for(i = 0; i < 600; i++) |
| 104 | { |
| 105 | Temp = i; |
| 106 | Temp += i; |
| 107 | } |
| 108 | #endif |
| 109 | } |
| 110 | |
| 111 | /* |
| 112 | * This function set/reset the SCL GPIO pin |
| 113 | * |
| 114 | * Parameters: |
| 115 | * value - Bit value to set to the SCL or SDA (0 = low, 1 = high) |
| 116 | * |
| 117 | * Notes: |
| 118 | * When setting SCL to high, just set the GPIO as input where the pull up |
| 119 | * resistor will pull the signal up. Do not use software to pull up the |
| 120 | * signal because the i2c will fail when other device try to drive the |
| 121 | * signal due to SM50x will drive the signal to always high. |
| 122 | */ |
| 123 | void swI2CSCL(unsigned char value) |
| 124 | { |
| 125 | unsigned long ulGPIOData; |
| 126 | unsigned long ulGPIODirection; |
| 127 | |
| 128 | ulGPIODirection = PEEK32(g_i2cClkGPIODataDirReg); |
| 129 | if (value) /* High */ |
| 130 | { |
| 131 | /* Set direction as input. This will automatically pull the signal up. */ |
| 132 | ulGPIODirection &= ~(1 << g_i2cClockGPIO); |
| 133 | POKE32(g_i2cClkGPIODataDirReg, ulGPIODirection); |
| 134 | } |
| 135 | else /* Low */ |
| 136 | { |
| 137 | /* Set the signal down */ |
| 138 | ulGPIOData = PEEK32(g_i2cClkGPIODataReg); |
| 139 | ulGPIOData &= ~(1 << g_i2cClockGPIO); |
| 140 | POKE32(g_i2cClkGPIODataReg, ulGPIOData); |
| 141 | |
| 142 | /* Set direction as output */ |
| 143 | ulGPIODirection |= (1 << g_i2cClockGPIO); |
| 144 | POKE32(g_i2cClkGPIODataDirReg, ulGPIODirection); |
| 145 | } |
| 146 | } |
| 147 | |
| 148 | /* |
| 149 | * This function set/reset the SDA GPIO pin |
| 150 | * |
| 151 | * Parameters: |
| 152 | * value - Bit value to set to the SCL or SDA (0 = low, 1 = high) |
| 153 | * |
| 154 | * Notes: |
| 155 | * When setting SCL to high, just set the GPIO as input where the pull up |
| 156 | * resistor will pull the signal up. Do not use software to pull up the |
| 157 | * signal because the i2c will fail when other device try to drive the |
| 158 | * signal due to SM50x will drive the signal to always high. |
| 159 | */ |
| 160 | void swI2CSDA(unsigned char value) |
| 161 | { |
| 162 | unsigned long ulGPIOData; |
| 163 | unsigned long ulGPIODirection; |
| 164 | |
| 165 | ulGPIODirection = PEEK32(g_i2cDataGPIODataDirReg); |
| 166 | if (value) /* High */ |
| 167 | { |
| 168 | /* Set direction as input. This will automatically pull the signal up. */ |
| 169 | ulGPIODirection &= ~(1 << g_i2cDataGPIO); |
| 170 | POKE32(g_i2cDataGPIODataDirReg, ulGPIODirection); |
| 171 | } |
| 172 | else /* Low */ |
| 173 | { |
| 174 | /* Set the signal down */ |
| 175 | ulGPIOData = PEEK32(g_i2cDataGPIODataReg); |
| 176 | ulGPIOData &= ~(1 << g_i2cDataGPIO); |
| 177 | POKE32(g_i2cDataGPIODataReg, ulGPIOData); |
| 178 | |
| 179 | /* Set direction as output */ |
| 180 | ulGPIODirection |= (1 << g_i2cDataGPIO); |
| 181 | POKE32(g_i2cDataGPIODataDirReg, ulGPIODirection); |
| 182 | } |
| 183 | } |
| 184 | |
| 185 | /* |
| 186 | * This function read the data from the SDA GPIO pin |
| 187 | * |
| 188 | * Return Value: |
| 189 | * The SDA data bit sent by the Slave |
| 190 | */ |
| 191 | static unsigned char swI2CReadSDA(void) |
| 192 | { |
| 193 | unsigned long ulGPIODirection; |
| 194 | unsigned long ulGPIOData; |
| 195 | |
| 196 | /* Make sure that the direction is input (High) */ |
| 197 | ulGPIODirection = PEEK32(g_i2cDataGPIODataDirReg); |
| 198 | if ((ulGPIODirection & (1 << g_i2cDataGPIO)) != (~(1 << g_i2cDataGPIO))) |
| 199 | { |
| 200 | ulGPIODirection &= ~(1 << g_i2cDataGPIO); |
| 201 | POKE32(g_i2cDataGPIODataDirReg, ulGPIODirection); |
| 202 | } |
| 203 | |
| 204 | /* Now read the SDA line */ |
| 205 | ulGPIOData = PEEK32(g_i2cDataGPIODataReg); |
| 206 | if (ulGPIOData & (1 << g_i2cDataGPIO)) |
| 207 | return 1; |
| 208 | else |
| 209 | return 0; |
| 210 | } |
| 211 | |
| 212 | /* |
| 213 | * This function sends ACK signal |
| 214 | */ |
| 215 | static void swI2CAck(void) |
| 216 | { |
| 217 | return; /* Single byte read is ok without it. */ |
| 218 | } |
| 219 | |
| 220 | /* |
| 221 | * This function sends the start command to the slave device |
| 222 | */ |
| 223 | static void swI2CStart(void) |
| 224 | { |
| 225 | /* Start I2C */ |
| 226 | swI2CSDA(1); |
| 227 | swI2CSCL(1); |
| 228 | swI2CSDA(0); |
| 229 | } |
| 230 | |
| 231 | /* |
| 232 | * This function sends the stop command to the slave device |
| 233 | */ |
| 234 | static void swI2CStop(void) |
| 235 | { |
| 236 | /* Stop the I2C */ |
| 237 | swI2CSCL(1); |
| 238 | swI2CSDA(0); |
| 239 | swI2CSDA(1); |
| 240 | } |
| 241 | |
| 242 | /* |
| 243 | * This function writes one byte to the slave device |
| 244 | * |
| 245 | * Parameters: |
| 246 | * data - Data to be write to the slave device |
| 247 | * |
| 248 | * Return Value: |
| 249 | * 0 - Success |
| 250 | * -1 - Fail to write byte |
| 251 | */ |
| 252 | static long swI2CWriteByte(unsigned char data) |
| 253 | { |
| 254 | unsigned char value = data; |
| 255 | int i; |
| 256 | |
| 257 | /* Sending the data bit by bit */ |
| 258 | for (i = 0; i < 8; i++) |
| 259 | { |
| 260 | /* Set SCL to low */ |
| 261 | swI2CSCL(0); |
| 262 | |
| 263 | /* Send data bit */ |
| 264 | if ((value & 0x80) != 0) |
| 265 | swI2CSDA(1); |
| 266 | else |
| 267 | swI2CSDA(0); |
| 268 | |
| 269 | swI2CWait(); |
| 270 | |
| 271 | /* Toggle clk line to one */ |
| 272 | swI2CSCL(1); |
| 273 | swI2CWait(); |
| 274 | |
| 275 | /* Shift byte to be sent */ |
| 276 | value = value << 1; |
| 277 | } |
| 278 | |
| 279 | /* Set the SCL Low and SDA High (prepare to get input) */ |
| 280 | swI2CSCL(0); |
| 281 | swI2CSDA(1); |
| 282 | |
| 283 | /* Set the SCL High for ack */ |
| 284 | swI2CWait(); |
| 285 | swI2CSCL(1); |
| 286 | swI2CWait(); |
| 287 | |
| 288 | /* Read SDA, until SDA==0 */ |
| 289 | for(i = 0; i < 0xff; i++) |
| 290 | { |
| 291 | if (!swI2CReadSDA()) |
| 292 | break; |
| 293 | |
| 294 | swI2CSCL(0); |
| 295 | swI2CWait(); |
| 296 | swI2CSCL(1); |
| 297 | swI2CWait(); |
| 298 | } |
| 299 | |
| 300 | /* Set the SCL Low and SDA High */ |
| 301 | swI2CSCL(0); |
| 302 | swI2CSDA(1); |
| 303 | |
| 304 | if (i < 0xff) |
| 305 | return 0; |
| 306 | else |
| 307 | return -1; |
| 308 | } |
| 309 | |
| 310 | /* |
| 311 | * This function reads one byte from the slave device |
| 312 | * |
| 313 | * Parameters: |
| 314 | * ack - Flag to indicate either to send the acknowledge |
| 315 | * message to the slave device or not |
| 316 | * |
| 317 | * Return Value: |
| 318 | * One byte data read from the Slave device |
| 319 | */ |
| 320 | static unsigned char swI2CReadByte(unsigned char ack) |
| 321 | { |
| 322 | int i; |
| 323 | unsigned char data = 0; |
| 324 | |
| 325 | for(i = 7; i >= 0; i--) |
| 326 | { |
| 327 | /* Set the SCL to Low and SDA to High (Input) */ |
| 328 | swI2CSCL(0); |
| 329 | swI2CSDA(1); |
| 330 | swI2CWait(); |
| 331 | |
| 332 | /* Set the SCL High */ |
| 333 | swI2CSCL(1); |
| 334 | swI2CWait(); |
| 335 | |
| 336 | /* Read data bits from SDA */ |
| 337 | data |= (swI2CReadSDA() << i); |
| 338 | } |
| 339 | |
| 340 | if (ack) |
| 341 | swI2CAck(); |
| 342 | |
| 343 | /* Set the SCL Low and SDA High */ |
| 344 | swI2CSCL(0); |
| 345 | swI2CSDA(1); |
| 346 | |
| 347 | return data; |
| 348 | } |
| 349 | |
| 350 | /* |
| 351 | * This function initializes GPIO port for SW I2C communication. |
| 352 | * |
| 353 | * Parameters: |
| 354 | * i2cClkGPIO - The GPIO pin to be used as i2c SCL |
| 355 | * i2cDataGPIO - The GPIO pin to be used as i2c SDA |
| 356 | * |
| 357 | * Return Value: |
| 358 | * -1 - Fail to initialize the i2c |
| 359 | * 0 - Success |
| 360 | */ |
| 361 | static long swI2CInit_SM750LE(unsigned char i2cClkGPIO, |
| 362 | unsigned char i2cDataGPIO) |
| 363 | { |
| 364 | int i; |
| 365 | |
| 366 | /* Initialize the GPIO pin for the i2c Clock Register */ |
| 367 | g_i2cClkGPIODataReg = GPIO_DATA_SM750LE; |
| 368 | g_i2cClkGPIODataDirReg = GPIO_DATA_DIRECTION_SM750LE; |
| 369 | |
| 370 | /* Initialize the Clock GPIO Offset */ |
| 371 | g_i2cClockGPIO = i2cClkGPIO; |
| 372 | |
| 373 | /* Initialize the GPIO pin for the i2c Data Register */ |
| 374 | g_i2cDataGPIODataReg = GPIO_DATA_SM750LE; |
| 375 | g_i2cDataGPIODataDirReg = GPIO_DATA_DIRECTION_SM750LE; |
| 376 | |
| 377 | /* Initialize the Data GPIO Offset */ |
| 378 | g_i2cDataGPIO = i2cDataGPIO; |
| 379 | |
| 380 | /* Note that SM750LE don't have GPIO MUX and power is always on */ |
| 381 | |
| 382 | /* Clear the i2c lines. */ |
| 383 | for(i = 0; i < 9; i++) |
| 384 | swI2CStop(); |
| 385 | |
| 386 | return 0; |
| 387 | } |
| 388 | |
| 389 | /* |
| 390 | * This function initializes the i2c attributes and bus |
| 391 | * |
| 392 | * Parameters: |
| 393 | * i2cClkGPIO - The GPIO pin to be used as i2c SCL |
| 394 | * i2cDataGPIO - The GPIO pin to be used as i2c SDA |
| 395 | * |
| 396 | * Return Value: |
| 397 | * -1 - Fail to initialize the i2c |
| 398 | * 0 - Success |
| 399 | */ |
| 400 | long swI2CInit( |
| 401 | unsigned char i2cClkGPIO, |
| 402 | unsigned char i2cDataGPIO |
| 403 | ) |
| 404 | { |
| 405 | int i; |
| 406 | |
| 407 | /* Return 0 if the GPIO pins to be used is out of range. The range is only from [0..63] */ |
| 408 | if ((i2cClkGPIO > 31) || (i2cDataGPIO > 31)) |
| 409 | return -1; |
| 410 | |
| 411 | if (getChipType() == SM750LE) |
| 412 | return swI2CInit_SM750LE(i2cClkGPIO, i2cDataGPIO); |
| 413 | |
| 414 | /* Initialize the GPIO pin for the i2c Clock Register */ |
| 415 | g_i2cClkGPIOMuxReg = GPIO_MUX; |
| 416 | g_i2cClkGPIODataReg = GPIO_DATA; |
| 417 | g_i2cClkGPIODataDirReg = GPIO_DATA_DIRECTION; |
| 418 | |
| 419 | /* Initialize the Clock GPIO Offset */ |
| 420 | g_i2cClockGPIO = i2cClkGPIO; |
| 421 | |
| 422 | /* Initialize the GPIO pin for the i2c Data Register */ |
| 423 | g_i2cDataGPIOMuxReg = GPIO_MUX; |
| 424 | g_i2cDataGPIODataReg = GPIO_DATA; |
| 425 | g_i2cDataGPIODataDirReg = GPIO_DATA_DIRECTION; |
| 426 | |
| 427 | /* Initialize the Data GPIO Offset */ |
| 428 | g_i2cDataGPIO = i2cDataGPIO; |
| 429 | |
| 430 | /* Enable the GPIO pins for the i2c Clock and Data (GPIO MUX) */ |
| 431 | POKE32(g_i2cClkGPIOMuxReg, |
| 432 | PEEK32(g_i2cClkGPIOMuxReg) & ~(1 << g_i2cClockGPIO)); |
| 433 | POKE32(g_i2cDataGPIOMuxReg, |
| 434 | PEEK32(g_i2cDataGPIOMuxReg) & ~(1 << g_i2cDataGPIO)); |
| 435 | |
| 436 | /* Enable GPIO power */ |
| 437 | enableGPIO(1); |
| 438 | |
| 439 | /* Clear the i2c lines. */ |
| 440 | for(i = 0; i < 9; i++) |
| 441 | swI2CStop(); |
| 442 | |
| 443 | return 0; |
| 444 | } |
| 445 | |
| 446 | /* |
| 447 | * This function reads the slave device's register |
| 448 | * |
| 449 | * Parameters: |
| 450 | * deviceAddress - i2c Slave device address which register |
| 451 | * to be read from |
| 452 | * registerIndex - Slave device's register to be read |
| 453 | * |
| 454 | * Return Value: |
| 455 | * Register value |
| 456 | */ |
| 457 | unsigned char swI2CReadReg( |
| 458 | unsigned char deviceAddress, |
| 459 | unsigned char registerIndex |
| 460 | ) |
| 461 | { |
| 462 | unsigned char data; |
| 463 | |
| 464 | /* Send the Start signal */ |
| 465 | swI2CStart(); |
| 466 | |
| 467 | /* Send the device address */ |
| 468 | swI2CWriteByte(deviceAddress); |
| 469 | |
| 470 | /* Send the register index */ |
| 471 | swI2CWriteByte(registerIndex); |
| 472 | |
| 473 | /* Get the bus again and get the data from the device read address */ |
| 474 | swI2CStart(); |
| 475 | swI2CWriteByte(deviceAddress + 1); |
| 476 | data = swI2CReadByte(1); |
| 477 | |
| 478 | /* Stop swI2C and release the bus */ |
| 479 | swI2CStop(); |
| 480 | |
| 481 | return data; |
| 482 | } |
| 483 | |
| 484 | /* |
| 485 | * This function writes a value to the slave device's register |
| 486 | * |
| 487 | * Parameters: |
| 488 | * deviceAddress - i2c Slave device address which register |
| 489 | * to be written |
| 490 | * registerIndex - Slave device's register to be written |
| 491 | * data - Data to be written to the register |
| 492 | * |
| 493 | * Result: |
| 494 | * 0 - Success |
| 495 | * -1 - Fail |
| 496 | */ |
| 497 | long swI2CWriteReg( |
| 498 | unsigned char deviceAddress, |
| 499 | unsigned char registerIndex, |
| 500 | unsigned char data |
| 501 | ) |
| 502 | { |
| 503 | long returnValue = 0; |
| 504 | |
| 505 | /* Send the Start signal */ |
| 506 | swI2CStart(); |
| 507 | |
| 508 | /* Send the device address and read the data. All should return success |
| 509 | in order for the writing processed to be successful |
| 510 | */ |
| 511 | if ((swI2CWriteByte(deviceAddress) != 0) || |
| 512 | (swI2CWriteByte(registerIndex) != 0) || |
| 513 | (swI2CWriteByte(data) != 0)) |
| 514 | { |
| 515 | returnValue = -1; |
| 516 | } |
| 517 | |
| 518 | /* Stop i2c and release the bus */ |
| 519 | swI2CStop(); |
| 520 | |
| 521 | return returnValue; |
| 522 | } |