drivers/i2c/soft_i2c.c

   1 /*
   2  * (C) Copyright 2009
   3  * Heiko Schocher, DENX Software Engineering, hs@denx.de.
   4  * Changes for multibus/multiadapter I2C support.
   5  *
   6  * (C) Copyright 2001, 2002
   7  * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
   8  *
   9  * SPDX-License-Identifier:     GPL-2.0+
  10  *
  11  * This has been changed substantially by Gerald Van Baren, Custom IDEAS,
  12  * vanbaren@cideas.com.  It was heavily influenced by LiMon, written by
  13  * Neil Russell.
  14  *
  15  * NOTE: This driver should be converted to driver model before June 2017.
  16  * Please see doc/driver-model/i2c-howto.txt for instructions.
  17  */
  18
  19 #include <common.h>
  20 #ifdef  CONFIG_MPC8260                  /* only valid for MPC8260 */
  21 #include <ioports.h>
  22 #include <asm/io.h>
  23 #endif
  24 #if defined(CONFIG_AT91FAMILY)
  25 #include <asm/io.h>
  26 #include <asm/arch/hardware.h>
  27 #include <asm/arch/at91_pio.h>
  28 #ifdef CONFIG_ATMEL_LEGACY
  29 #include <asm/arch/gpio.h>
  30 #endif
  31 #endif
  32 #if defined(CONFIG_MPC852T) || defined(CONFIG_MPC866)
  33 #include <asm/io.h>
  34 #endif
  35 #include <i2c.h>
  36
  37 #if defined(CONFIG_SOFT_I2C_GPIO_SCL)
  38 # include <asm/gpio.h>
  39
  40 # ifndef I2C_GPIO_SYNC
  41 #  define I2C_GPIO_SYNC
  42 # endif
  43
  44 # ifndef I2C_INIT
  45 #  define I2C_INIT \
  46         do { \
  47                 gpio_request(CONFIG_SOFT_I2C_GPIO_SCL, "soft_i2c"); \
  48                 gpio_request(CONFIG_SOFT_I2C_GPIO_SDA, "soft_i2c"); \
  49         } while (0)
  50 # endif
  51
  52 # ifndef I2C_ACTIVE
  53 #  define I2C_ACTIVE do { } while (0)
  54 # endif
  55
  56 # ifndef I2C_TRISTATE
  57 #  define I2C_TRISTATE do { } while (0)
  58 # endif
  59
  60 # ifndef I2C_READ
  61 #  define I2C_READ gpio_get_value(CONFIG_SOFT_I2C_GPIO_SDA)
  62 # endif
  63
  64 # ifndef I2C_SDA
  65 #  define I2C_SDA(bit) \
  66         do { \
  67                 if (bit) \
  68                         gpio_direction_input(CONFIG_SOFT_I2C_GPIO_SDA); \
  69                 else \
  70                         gpio_direction_output(CONFIG_SOFT_I2C_GPIO_SDA, 0); \
  71                 I2C_GPIO_SYNC; \
  72         } while (0)
  73 # endif
  74
  75 # ifndef I2C_SCL
  76 #  define I2C_SCL(bit) \
  77         do { \
  78                 gpio_direction_output(CONFIG_SOFT_I2C_GPIO_SCL, bit); \
  79                 I2C_GPIO_SYNC; \
  80         } while (0)
  81 # endif
  82
  83 # ifndef I2C_DELAY
  84 #  define I2C_DELAY udelay(5)   /* 1/4 I2C clock duration */
  85 # endif
  86
  87 #endif
  88
  89 /* #define      DEBUG_I2C       */
  90
  91 DECLARE_GLOBAL_DATA_PTR;
  92
  93 #ifndef I2C_SOFT_DECLARATIONS
  94 #  define I2C_SOFT_DECLARATIONS
  95 #endif
  96
  97 #if !defined(CONFIG_SYS_I2C_SOFT_SPEED)
  98 #define CONFIG_SYS_I2C_SOFT_SPEED CONFIG_SYS_I2C_SPEED
  99 #endif
 100 #if !defined(CONFIG_SYS_I2C_SOFT_SLAVE)
 101 #define CONFIG_SYS_I2C_SOFT_SLAVE CONFIG_SYS_I2C_SLAVE
 102 #endif
 103
 104 /*-----------------------------------------------------------------------
 105  * Definitions
 106  */
 107 #define RETRIES         0
 108
 109 #define I2C_ACK         0               /* PD_SDA level to ack a byte */
 110 #define I2C_NOACK       1               /* PD_SDA level to noack a byte */
 111
 112
 113 #ifdef DEBUG_I2C
 114 #define PRINTD(fmt,args...)     do {    \
 115                 printf (fmt ,##args);   \
 116         } while (0)
 117 #else
 118 #define PRINTD(fmt,args...)
 119 #endif
 120
 121 /*-----------------------------------------------------------------------
 122  * Local functions
 123  */
 124 #if !defined(CONFIG_SYS_I2C_INIT_BOARD)
 125 static void  send_reset (void);
 126 #endif
 127 static void  send_start (void);
 128 static void  send_stop  (void);
 129 static void  send_ack   (int);
 130 static int   write_byte (uchar byte);
 131 static uchar read_byte  (int);
 132
 133 #if !defined(CONFIG_SYS_I2C_INIT_BOARD)
 134 /*-----------------------------------------------------------------------
 135  * Send a reset sequence consisting of 9 clocks with the data signal high
 136  * to clock any confused device back into an idle state.  Also send a
 137  * <stop> at the end of the sequence for belts & suspenders.
 138  */
 139 static void send_reset(void)
 140 {
 141         I2C_SOFT_DECLARATIONS   /* intentional without ';' */
 142         int j;
 143
 144         I2C_SCL(1);
 145         I2C_SDA(1);
 146 #ifdef  I2C_INIT
 147         I2C_INIT;
 148 #endif
 149         I2C_TRISTATE;
 150         for(j = 0; j < 9; j++) {
 151                 I2C_SCL(0);
 152                 I2C_DELAY;
 153                 I2C_DELAY;
 154                 I2C_SCL(1);
 155                 I2C_DELAY;
 156                 I2C_DELAY;
 157         }
 158         send_stop();
 159         I2C_TRISTATE;
 160 }
 161 #endif
 162
 163 /*-----------------------------------------------------------------------
 164  * START: High -> Low on SDA while SCL is High
 165  */
 166 static void send_start(void)
 167 {
 168         I2C_SOFT_DECLARATIONS   /* intentional without ';' */
 169
 170         I2C_DELAY;
 171         I2C_SDA(1);
 172         I2C_ACTIVE;
 173         I2C_DELAY;
 174         I2C_SCL(1);
 175         I2C_DELAY;
 176         I2C_SDA(0);
 177         I2C_DELAY;
 178 }
 179
 180 /*-----------------------------------------------------------------------
 181  * STOP: Low -> High on SDA while SCL is High
 182  */
 183 static void send_stop(void)
 184 {
 185         I2C_SOFT_DECLARATIONS   /* intentional without ';' */
 186
 187         I2C_SCL(0);
 188         I2C_DELAY;
 189         I2C_SDA(0);
 190         I2C_ACTIVE;
 191         I2C_DELAY;
 192         I2C_SCL(1);
 193         I2C_DELAY;
 194         I2C_SDA(1);
 195         I2C_DELAY;
 196         I2C_TRISTATE;
 197 }
 198
 199 /*-----------------------------------------------------------------------
 200  * ack should be I2C_ACK or I2C_NOACK
 201  */
 202 static void send_ack(int ack)
 203 {
 204         I2C_SOFT_DECLARATIONS   /* intentional without ';' */
 205
 206         I2C_SCL(0);
 207         I2C_DELAY;
 208         I2C_ACTIVE;
 209         I2C_SDA(ack);
 210         I2C_DELAY;
 211         I2C_SCL(1);
 212         I2C_DELAY;
 213         I2C_DELAY;
 214         I2C_SCL(0);
 215         I2C_DELAY;
 216 }
 217
 218 /*-----------------------------------------------------------------------
 219  * Send 8 bits and look for an acknowledgement.
 220  */
 221 static int write_byte(uchar data)
 222 {
 223         I2C_SOFT_DECLARATIONS   /* intentional without ';' */
 224         int j;
 225         int nack;
 226
 227         I2C_ACTIVE;
 228         for(j = 0; j < 8; j++) {
 229                 I2C_SCL(0);
 230                 I2C_DELAY;
 231                 I2C_SDA(data & 0x80);
 232                 I2C_DELAY;
 233                 I2C_SCL(1);
 234                 I2C_DELAY;
 235                 I2C_DELAY;
 236
 237                 data <<= 1;
 238         }
 239
 240         /*
 241          * Look for an <ACK>(negative logic) and return it.
 242          */
 243         I2C_SCL(0);
 244         I2C_DELAY;
 245         I2C_SDA(1);
 246         I2C_TRISTATE;
 247         I2C_DELAY;
 248         I2C_SCL(1);
 249         I2C_DELAY;
 250         I2C_DELAY;
 251         nack = I2C_READ;
 252         I2C_SCL(0);
 253         I2C_DELAY;
 254         I2C_ACTIVE;
 255
 256         return(nack);   /* not a nack is an ack */
 257 }
 258
 259 /*-----------------------------------------------------------------------
 260  * if ack == I2C_ACK, ACK the byte so can continue reading, else
 261  * send I2C_NOACK to end the read.
 262  */
 263 static uchar read_byte(int ack)
 264 {
 265         I2C_SOFT_DECLARATIONS   /* intentional without ';' */
 266         int  data;
 267         int  j;
 268
 269         /*
 270          * Read 8 bits, MSB first.
 271          */
 272         I2C_TRISTATE;
 273         I2C_SDA(1);
 274         data = 0;
 275         for(j = 0; j < 8; j++) {
 276                 I2C_SCL(0);
 277                 I2C_DELAY;
 278                 I2C_SCL(1);
 279                 I2C_DELAY;
 280                 data <<= 1;
 281                 data |= I2C_READ;
 282                 I2C_DELAY;
 283         }
 284         send_ack(ack);
 285
 286         return(data);
 287 }
 288
 289 /*-----------------------------------------------------------------------
 290  * Initialization
 291  */
 292 static void soft_i2c_init(struct i2c_adapter *adap, int speed, int slaveaddr)
 293 {
 294 #if defined(CONFIG_SYS_I2C_INIT_BOARD)
 295         /* call board specific i2c bus reset routine before accessing the   */
 296         /* environment, which might be in a chip on that bus. For details   */
 297         /* about this problem see doc/I2C_Edge_Conditions.                  */
 298         i2c_init_board();
 299 #else
 300         /*
 301          * WARNING: Do NOT save speed in a static variable: if the
 302          * I2C routines are called before RAM is initialized (to read
 303          * the DIMM SPD, for instance), RAM won't be usable and your
 304          * system will crash.
 305          */
 306         send_reset ();
 307 #endif
 308 }
 309
 310 /*-----------------------------------------------------------------------
 311  * Probe to see if a chip is present.  Also good for checking for the
 312  * completion of EEPROM writes since the chip stops responding until
 313  * the write completes (typically 10mSec).
 314  */
 315 static int soft_i2c_probe(struct i2c_adapter *adap, uint8_t addr)
 316 {
 317         int rc;
 318
 319         /*
 320          * perform 1 byte write transaction with just address byte
 321          * (fake write)
 322          */
 323         send_start();
 324         rc = write_byte ((addr << 1) | 0);
 325         send_stop();
 326
 327         return (rc ? 1 : 0);
 328 }
 329
 330 /*-----------------------------------------------------------------------
 331  * Read bytes
 332  */
 333 static int  soft_i2c_read(struct i2c_adapter *adap, uchar chip, uint addr,
 334                         int alen, uchar *buffer, int len)
 335 {
 336         int shift;
 337         PRINTD("i2c_read: chip %02X addr %02X alen %d buffer %p len %d\n",
 338                 chip, addr, alen, buffer, len);
 339
 340 #ifdef CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW
 341         /*
 342          * EEPROM chips that implement "address overflow" are ones
 343          * like Catalyst 24WC04/08/16 which has 9/10/11 bits of
 344          * address and the extra bits end up in the "chip address"
 345          * bit slots. This makes a 24WC08 (1Kbyte) chip look like
 346          * four 256 byte chips.
 347          *
 348          * Note that we consider the length of the address field to
 349          * still be one byte because the extra address bits are
 350          * hidden in the chip address.
 351          */
 352         chip |= ((addr >> (alen * 8)) & CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW);
 353
 354         PRINTD("i2c_read: fix addr_overflow: chip %02X addr %02X\n",
 355                 chip, addr);
 356 #endif
 357
 358         /*
 359          * Do the addressing portion of a write cycle to set the
 360          * chip's address pointer.  If the address length is zero,
 361          * don't do the normal write cycle to set the address pointer,
 362          * there is no address pointer in this chip.
 363          */
 364         send_start();
 365         if(alen > 0) {
 366                 if(write_byte(chip << 1)) {     /* write cycle */
 367                         send_stop();
 368                         PRINTD("i2c_read, no chip responded %02X\n", chip);
 369                         return(1);
 370                 }
 371                 shift = (alen-1) * 8;
 372                 while(alen-- > 0) {
 373                         if(write_byte(addr >> shift)) {
 374                                 PRINTD("i2c_read, address not <ACK>ed\n");
 375                                 return(1);
 376                         }
 377                         shift -= 8;
 378                 }
 379
 380                 /* Some I2C chips need a stop/start sequence here,
 381                  * other chips don't work with a full stop and need
 382                  * only a start.  Default behaviour is to send the
 383                  * stop/start sequence.
 384                  */
 385 #ifdef CONFIG_SOFT_I2C_READ_REPEATED_START
 386                 send_start();
 387 #else
 388                 send_stop();
 389                 send_start();
 390 #endif
 391         }
 392         /*
 393          * Send the chip address again, this time for a read cycle.
 394          * Then read the data.  On the last byte, we do a NACK instead
 395          * of an ACK(len == 0) to terminate the read.
 396          */
 397         write_byte((chip << 1) | 1);    /* read cycle */
 398         while(len-- > 0) {
 399                 *buffer++ = read_byte(len == 0);
 400         }
 401         send_stop();
 402         return(0);
 403 }
 404
 405 /*-----------------------------------------------------------------------
 406  * Write bytes
 407  */
 408 static int  soft_i2c_write(struct i2c_adapter *adap, uchar chip, uint addr,
 409                         int alen, uchar *buffer, int len)
 410 {
 411         int shift, failures = 0;
 412
 413         PRINTD("i2c_write: chip %02X addr %02X alen %d buffer %p len %d\n",
 414                 chip, addr, alen, buffer, len);
 415
 416         send_start();
 417         if(write_byte(chip << 1)) {     /* write cycle */
 418                 send_stop();
 419                 PRINTD("i2c_write, no chip responded %02X\n", chip);
 420                 return(1);
 421         }
 422         shift = (alen-1) * 8;
 423         while(alen-- > 0) {
 424                 if(write_byte(addr >> shift)) {
 425                         PRINTD("i2c_write, address not <ACK>ed\n");
 426                         return(1);
 427                 }
 428                 shift -= 8;
 429         }
 430
 431         while(len-- > 0) {
 432                 if(write_byte(*buffer++)) {
 433                         failures++;
 434                 }
 435         }
 436         send_stop();
 437         return(failures);
 438 }
 439
 440 /*
 441  * Register soft i2c adapters
 442  */
 443 U_BOOT_I2C_ADAP_COMPLETE(soft00, soft_i2c_init, soft_i2c_probe,
 444                          soft_i2c_read, soft_i2c_write, NULL,
 445                          CONFIG_SYS_I2C_SOFT_SPEED, CONFIG_SYS_I2C_SOFT_SLAVE,
 446                          0)
 447 #if defined(I2C_SOFT_DECLARATIONS2)
 448 U_BOOT_I2C_ADAP_COMPLETE(soft01, soft_i2c_init, soft_i2c_probe,
 449                          soft_i2c_read, soft_i2c_write, NULL,
 450                          CONFIG_SYS_I2C_SOFT_SPEED_2,
 451                          CONFIG_SYS_I2C_SOFT_SLAVE_2,
 452                          1)
 453 #endif
 454 #if defined(I2C_SOFT_DECLARATIONS3)
 455 U_BOOT_I2C_ADAP_COMPLETE(soft02, soft_i2c_init, soft_i2c_probe,
 456                          soft_i2c_read, soft_i2c_write, NULL,
 457                          CONFIG_SYS_I2C_SOFT_SPEED_3,
 458                          CONFIG_SYS_I2C_SOFT_SLAVE_3,
 459                          2)
 460 #endif
 461 #if defined(I2C_SOFT_DECLARATIONS4)
 462 U_BOOT_I2C_ADAP_COMPLETE(soft03, soft_i2c_init, soft_i2c_probe,
 463                          soft_i2c_read, soft_i2c_write, NULL,
 464                          CONFIG_SYS_I2C_SOFT_SPEED_4,
 465                          CONFIG_SYS_I2C_SOFT_SLAVE_4,
 466                          3)
 467 #endif
 468 #if defined(I2C_SOFT_DECLARATIONS5)
 469 U_BOOT_I2C_ADAP_COMPLETE(soft04, soft_i2c_init, soft_i2c_probe,
 470                          soft_i2c_read, soft_i2c_write, NULL,
 471                          CONFIG_SYS_I2C_SOFT_SPEED_5,
 472                          CONFIG_SYS_I2C_SOFT_SLAVE_5,
 473                          4)
 474 #endif
 475 #if defined(I2C_SOFT_DECLARATIONS6)
 476 U_BOOT_I2C_ADAP_COMPLETE(soft05, soft_i2c_init, soft_i2c_probe,
 477                          soft_i2c_read, soft_i2c_write, NULL,
 478                          CONFIG_SYS_I2C_SOFT_SPEED_6,
 479                          CONFIG_SYS_I2C_SOFT_SLAVE_6,
 480                          5)
 481 #endif
 482 #if defined(I2C_SOFT_DECLARATIONS7)
 483 U_BOOT_I2C_ADAP_COMPLETE(soft06, soft_i2c_init, soft_i2c_probe,
 484                          soft_i2c_read, soft_i2c_write, NULL,
 485                          CONFIG_SYS_I2C_SOFT_SPEED_7,
 486                          CONFIG_SYS_I2C_SOFT_SLAVE_7,
 487                          6)
 488 #endif
 489 #if defined(I2C_SOFT_DECLARATIONS8)
 490 U_BOOT_I2C_ADAP_COMPLETE(soft07, soft_i2c_init, soft_i2c_probe,
 491                          soft_i2c_read, soft_i2c_write, NULL,
 492                          CONFIG_SYS_I2C_SOFT_SPEED_8,
 493                          CONFIG_SYS_I2C_SOFT_SLAVE_8,
 494                          7)
 495 #endif
 496 #if defined(I2C_SOFT_DECLARATIONS9)
 497 U_BOOT_I2C_ADAP_COMPLETE(soft08, soft_i2c_init, soft_i2c_probe,
 498                          soft_i2c_read, soft_i2c_write, NULL,
 499                          CONFIG_SYS_I2C_SOFT_SPEED_9,
 500                          CONFIG_SYS_I2C_SOFT_SLAVE_9,
 501                          8)
 502 #endif
 503 #if defined(I2C_SOFT_DECLARATIONS10)
 504 U_BOOT_I2C_ADAP_COMPLETE(soft09, soft_i2c_init, soft_i2c_probe,
 505                          soft_i2c_read, soft_i2c_write, NULL,
 506                          CONFIG_SYS_I2C_SOFT_SPEED_10,
 507                          CONFIG_SYS_I2C_SOFT_SLAVE_10,
 508                          9)
 509 #endif
 510 #if defined(I2C_SOFT_DECLARATIONS11)
 511 U_BOOT_I2C_ADAP_COMPLETE(soft10, soft_i2c_init, soft_i2c_probe,
 512                          soft_i2c_read, soft_i2c_write, NULL,
 513                          CONFIG_SYS_I2C_SOFT_SPEED_11,
 514                          CONFIG_SYS_I2C_SOFT_SLAVE_11,
 515                          10)
 516 #endif
 517 #if defined(I2C_SOFT_DECLARATIONS12)
 518 U_BOOT_I2C_ADAP_COMPLETE(soft11, soft_i2c_init, soft_i2c_probe,
 519                          soft_i2c_read, soft_i2c_write, NULL,
 520                          CONFIG_SYS_I2C_SOFT_SPEED_12,
 521                          CONFIG_SYS_I2C_SOFT_SLAVE_12,
 522                          11)
 523 #endif