1 /* 2 * (C) Copyright 2001, 2002 3 * Wolfgang Denk, DENX Software Engineering, wd@denx.de. 4 * 5 * See file CREDITS for list of people who contributed to this 6 * project. 7 * 8 * This program is free software; you can redistribute it and/or 9 * modify it under the terms of the GNU General Public License as 10 * published by the Free Software Foundation; either version 2 of 11 * the License, or (at your option) any later version. 12 * 13 * This program is distributed in the hope that it will be useful, 14 * but WITHOUT ANY WARRANTY; without even the implied warranty of 15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 16 * GNU General Public License for more details. 17 * 18 * You should have received a copy of the GNU General Public License 19 * along with this program; if not, write to the Free Software 20 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, 21 * MA 02111-1307 USA 22 * 23 * This has been changed substantially by Gerald Van Baren, Custom IDEAS, 24 * vanbaren@cideas.com. It was heavily influenced by LiMon, written by 25 * Neil Russell. 26 */ 27 28 #include <common.h> 29 #ifdef CONFIG_MPC8260 /* only valid for MPC8260 */ 30 #include <ioports.h> 31 #include <asm/io.h> 32 #endif 33 #if defined(CONFIG_AT91FAMILY) 34 #include <asm/io.h> 35 #include <asm/arch/hardware.h> 36 #include <asm/arch/at91_pio.h> 37 #ifdef CONFIG_AT91_LEGACY 38 #include <asm/arch/gpio.h> 39 #endif 40 #endif 41 #ifdef CONFIG_IXP425 /* only valid for IXP425 */ 42 #include <asm/arch/ixp425.h> 43 #endif 44 #ifdef CONFIG_LPC2292 45 #include <asm/arch/hardware.h> 46 #endif 47 #if defined(CONFIG_MPC852T) || defined(CONFIG_MPC866) 48 #include <asm/io.h> 49 #endif 50 #include <i2c.h> 51 52 #if defined(CONFIG_SOFT_I2C_GPIO_SCL) 53 # include <asm/gpio.h> 54 55 # ifndef I2C_GPIO_SYNC 56 # define I2C_GPIO_SYNC 57 # endif 58 59 # ifndef I2C_INIT 60 # define I2C_INIT \ 61 do { \ 62 gpio_request(CONFIG_SOFT_I2C_GPIO_SCL, "soft_i2c"); \ 63 gpio_request(CONFIG_SOFT_I2C_GPIO_SDA, "soft_i2c"); \ 64 } while (0) 65 # endif 66 67 # ifndef I2C_ACTIVE 68 # define I2C_ACTIVE do { } while (0) 69 # endif 70 71 # ifndef I2C_TRISTATE 72 # define I2C_TRISTATE do { } while (0) 73 # endif 74 75 # ifndef I2C_READ 76 # define I2C_READ gpio_get_value(CONFIG_SOFT_I2C_GPIO_SDA) 77 # endif 78 79 # ifndef I2C_SDA 80 # define I2C_SDA(bit) \ 81 do { \ 82 if (bit) \ 83 gpio_direction_input(CONFIG_SOFT_I2C_GPIO_SDA); \ 84 else \ 85 gpio_direction_output(CONFIG_SOFT_I2C_GPIO_SDA, 0); \ 86 I2C_GPIO_SYNC; \ 87 } while (0) 88 # endif 89 90 # ifndef I2C_SCL 91 # define I2C_SCL(bit) \ 92 do { \ 93 gpio_direction_output(CONFIG_SOFT_I2C_GPIO_SCL, bit); \ 94 I2C_GPIO_SYNC; \ 95 } while (0) 96 # endif 97 98 # ifndef I2C_DELAY 99 # define I2C_DELAY udelay(5) /* 1/4 I2C clock duration */ 100 # endif 101 102 #endif 103 104 /* #define DEBUG_I2C */ 105 106 #ifdef DEBUG_I2C 107 DECLARE_GLOBAL_DATA_PTR; 108 #endif 109 110 /*----------------------------------------------------------------------- 111 * Definitions 112 */ 113 114 #define RETRIES 0 115 116 #define I2C_ACK 0 /* PD_SDA level to ack a byte */ 117 #define I2C_NOACK 1 /* PD_SDA level to noack a byte */ 118 119 120 #ifdef DEBUG_I2C 121 #define PRINTD(fmt,args...) do { \ 122 if (gd->have_console) \ 123 printf (fmt ,##args); \ 124 } while (0) 125 #else 126 #define PRINTD(fmt,args...) 127 #endif 128 129 #if defined(CONFIG_I2C_MULTI_BUS) 130 static unsigned int i2c_bus_num __attribute__ ((section (".data"))) = 0; 131 #endif /* CONFIG_I2C_MULTI_BUS */ 132 133 /*----------------------------------------------------------------------- 134 * Local functions 135 */ 136 #if !defined(CONFIG_SYS_I2C_INIT_BOARD) 137 static void send_reset (void); 138 #endif 139 static void send_start (void); 140 static void send_stop (void); 141 static void send_ack (int); 142 static int write_byte (uchar byte); 143 static uchar read_byte (int); 144 145 #if !defined(CONFIG_SYS_I2C_INIT_BOARD) 146 /*----------------------------------------------------------------------- 147 * Send a reset sequence consisting of 9 clocks with the data signal high 148 * to clock any confused device back into an idle state. Also send a 149 * <stop> at the end of the sequence for belts & suspenders. 150 */ 151 static void send_reset(void) 152 { 153 I2C_SOFT_DECLARATIONS /* intentional without ';' */ 154 int j; 155 156 I2C_SCL(1); 157 I2C_SDA(1); 158 #ifdef I2C_INIT 159 I2C_INIT; 160 #endif 161 I2C_TRISTATE; 162 for(j = 0; j < 9; j++) { 163 I2C_SCL(0); 164 I2C_DELAY; 165 I2C_DELAY; 166 I2C_SCL(1); 167 I2C_DELAY; 168 I2C_DELAY; 169 } 170 send_stop(); 171 I2C_TRISTATE; 172 } 173 #endif 174 175 /*----------------------------------------------------------------------- 176 * START: High -> Low on SDA while SCL is High 177 */ 178 static void send_start(void) 179 { 180 I2C_SOFT_DECLARATIONS /* intentional without ';' */ 181 182 I2C_DELAY; 183 I2C_SDA(1); 184 I2C_ACTIVE; 185 I2C_DELAY; 186 I2C_SCL(1); 187 I2C_DELAY; 188 I2C_SDA(0); 189 I2C_DELAY; 190 } 191 192 /*----------------------------------------------------------------------- 193 * STOP: Low -> High on SDA while SCL is High 194 */ 195 static void send_stop(void) 196 { 197 I2C_SOFT_DECLARATIONS /* intentional without ';' */ 198 199 I2C_SCL(0); 200 I2C_DELAY; 201 I2C_SDA(0); 202 I2C_ACTIVE; 203 I2C_DELAY; 204 I2C_SCL(1); 205 I2C_DELAY; 206 I2C_SDA(1); 207 I2C_DELAY; 208 I2C_TRISTATE; 209 } 210 211 /*----------------------------------------------------------------------- 212 * ack should be I2C_ACK or I2C_NOACK 213 */ 214 static void send_ack(int ack) 215 { 216 I2C_SOFT_DECLARATIONS /* intentional without ';' */ 217 218 I2C_SCL(0); 219 I2C_DELAY; 220 I2C_ACTIVE; 221 I2C_SDA(ack); 222 I2C_DELAY; 223 I2C_SCL(1); 224 I2C_DELAY; 225 I2C_DELAY; 226 I2C_SCL(0); 227 I2C_DELAY; 228 } 229 230 /*----------------------------------------------------------------------- 231 * Send 8 bits and look for an acknowledgement. 232 */ 233 static int write_byte(uchar data) 234 { 235 I2C_SOFT_DECLARATIONS /* intentional without ';' */ 236 int j; 237 int nack; 238 239 I2C_ACTIVE; 240 for(j = 0; j < 8; j++) { 241 I2C_SCL(0); 242 I2C_DELAY; 243 I2C_SDA(data & 0x80); 244 I2C_DELAY; 245 I2C_SCL(1); 246 I2C_DELAY; 247 I2C_DELAY; 248 249 data <<= 1; 250 } 251 252 /* 253 * Look for an <ACK>(negative logic) and return it. 254 */ 255 I2C_SCL(0); 256 I2C_DELAY; 257 I2C_SDA(1); 258 I2C_TRISTATE; 259 I2C_DELAY; 260 I2C_SCL(1); 261 I2C_DELAY; 262 I2C_DELAY; 263 nack = I2C_READ; 264 I2C_SCL(0); 265 I2C_DELAY; 266 I2C_ACTIVE; 267 268 return(nack); /* not a nack is an ack */ 269 } 270 271 #if defined(CONFIG_I2C_MULTI_BUS) 272 /* 273 * Functions for multiple I2C bus handling 274 */ 275 unsigned int i2c_get_bus_num(void) 276 { 277 return i2c_bus_num; 278 } 279 280 int i2c_set_bus_num(unsigned int bus) 281 { 282 #if defined(CONFIG_I2C_MUX) 283 if (bus < CONFIG_SYS_MAX_I2C_BUS) { 284 i2c_bus_num = bus; 285 } else { 286 int ret; 287 288 ret = i2x_mux_select_mux(bus); 289 i2c_init_board(); 290 if (ret == 0) 291 i2c_bus_num = bus; 292 else 293 return ret; 294 } 295 #else 296 if (bus >= CONFIG_SYS_MAX_I2C_BUS) 297 return -1; 298 i2c_bus_num = bus; 299 #endif 300 return 0; 301 } 302 #endif 303 304 /*----------------------------------------------------------------------- 305 * if ack == I2C_ACK, ACK the byte so can continue reading, else 306 * send I2C_NOACK to end the read. 307 */ 308 static uchar read_byte(int ack) 309 { 310 I2C_SOFT_DECLARATIONS /* intentional without ';' */ 311 int data; 312 int j; 313 314 /* 315 * Read 8 bits, MSB first. 316 */ 317 I2C_TRISTATE; 318 I2C_SDA(1); 319 data = 0; 320 for(j = 0; j < 8; j++) { 321 I2C_SCL(0); 322 I2C_DELAY; 323 I2C_SCL(1); 324 I2C_DELAY; 325 data <<= 1; 326 data |= I2C_READ; 327 I2C_DELAY; 328 } 329 send_ack(ack); 330 331 return(data); 332 } 333 334 /*=====================================================================*/ 335 /* Public Functions */ 336 /*=====================================================================*/ 337 338 /*----------------------------------------------------------------------- 339 * Initialization 340 */ 341 void i2c_init (int speed, int slaveaddr) 342 { 343 #if defined(CONFIG_SYS_I2C_INIT_BOARD) 344 /* call board specific i2c bus reset routine before accessing the */ 345 /* environment, which might be in a chip on that bus. For details */ 346 /* about this problem see doc/I2C_Edge_Conditions. */ 347 i2c_init_board(); 348 #else 349 /* 350 * WARNING: Do NOT save speed in a static variable: if the 351 * I2C routines are called before RAM is initialized (to read 352 * the DIMM SPD, for instance), RAM won't be usable and your 353 * system will crash. 354 */ 355 send_reset (); 356 #endif 357 } 358 359 /*----------------------------------------------------------------------- 360 * Probe to see if a chip is present. Also good for checking for the 361 * completion of EEPROM writes since the chip stops responding until 362 * the write completes (typically 10mSec). 363 */ 364 int i2c_probe(uchar addr) 365 { 366 int rc; 367 368 /* 369 * perform 1 byte write transaction with just address byte 370 * (fake write) 371 */ 372 send_start(); 373 rc = write_byte ((addr << 1) | 0); 374 send_stop(); 375 376 return (rc ? 1 : 0); 377 } 378 379 /*----------------------------------------------------------------------- 380 * Read bytes 381 */ 382 int i2c_read(uchar chip, uint addr, int alen, uchar *buffer, int len) 383 { 384 int shift; 385 PRINTD("i2c_read: chip %02X addr %02X alen %d buffer %p len %d\n", 386 chip, addr, alen, buffer, len); 387 388 #ifdef CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW 389 /* 390 * EEPROM chips that implement "address overflow" are ones 391 * like Catalyst 24WC04/08/16 which has 9/10/11 bits of 392 * address and the extra bits end up in the "chip address" 393 * bit slots. This makes a 24WC08 (1Kbyte) chip look like 394 * four 256 byte chips. 395 * 396 * Note that we consider the length of the address field to 397 * still be one byte because the extra address bits are 398 * hidden in the chip address. 399 */ 400 chip |= ((addr >> (alen * 8)) & CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW); 401 402 PRINTD("i2c_read: fix addr_overflow: chip %02X addr %02X\n", 403 chip, addr); 404 #endif 405 406 /* 407 * Do the addressing portion of a write cycle to set the 408 * chip's address pointer. If the address length is zero, 409 * don't do the normal write cycle to set the address pointer, 410 * there is no address pointer in this chip. 411 */ 412 send_start(); 413 if(alen > 0) { 414 if(write_byte(chip << 1)) { /* write cycle */ 415 send_stop(); 416 PRINTD("i2c_read, no chip responded %02X\n", chip); 417 return(1); 418 } 419 shift = (alen-1) * 8; 420 while(alen-- > 0) { 421 if(write_byte(addr >> shift)) { 422 PRINTD("i2c_read, address not <ACK>ed\n"); 423 return(1); 424 } 425 shift -= 8; 426 } 427 428 /* Some I2C chips need a stop/start sequence here, 429 * other chips don't work with a full stop and need 430 * only a start. Default behaviour is to send the 431 * stop/start sequence. 432 */ 433 #ifdef CONFIG_SOFT_I2C_READ_REPEATED_START 434 send_start(); 435 #else 436 send_stop(); 437 send_start(); 438 #endif 439 } 440 /* 441 * Send the chip address again, this time for a read cycle. 442 * Then read the data. On the last byte, we do a NACK instead 443 * of an ACK(len == 0) to terminate the read. 444 */ 445 write_byte((chip << 1) | 1); /* read cycle */ 446 while(len-- > 0) { 447 *buffer++ = read_byte(len == 0); 448 } 449 send_stop(); 450 return(0); 451 } 452 453 /*----------------------------------------------------------------------- 454 * Write bytes 455 */ 456 int i2c_write(uchar chip, uint addr, int alen, uchar *buffer, int len) 457 { 458 int shift, failures = 0; 459 460 PRINTD("i2c_write: chip %02X addr %02X alen %d buffer %p len %d\n", 461 chip, addr, alen, buffer, len); 462 463 send_start(); 464 if(write_byte(chip << 1)) { /* write cycle */ 465 send_stop(); 466 PRINTD("i2c_write, no chip responded %02X\n", chip); 467 return(1); 468 } 469 shift = (alen-1) * 8; 470 while(alen-- > 0) { 471 if(write_byte(addr >> shift)) { 472 PRINTD("i2c_write, address not <ACK>ed\n"); 473 return(1); 474 } 475 shift -= 8; 476 } 477 478 while(len-- > 0) { 479 if(write_byte(*buffer++)) { 480 failures++; 481 } 482 } 483 send_stop(); 484 return(failures); 485 } 486