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 #if defined(CONFIG_AVR32)
  21 #include <asm/arch/portmux.h>
  22 #endif
  23 #if defined(CONFIG_AT91FAMILY)
  24 #include <asm/io.h>
  25 #include <asm/arch/hardware.h>
  26 #include <asm/arch/at91_pio.h>
  27 #ifdef CONFIG_ATMEL_LEGACY
  28 #include <asm/arch/gpio.h>
  29 #endif
  30 #endif
  31 #if defined(CONFIG_MPC852T) || defined(CONFIG_MPC866)
  32 #include <asm/io.h>
  33 #endif
  34 #include <i2c.h>
  35
  36 #if defined(CONFIG_SOFT_I2C_GPIO_SCL)
  37 # include <asm/gpio.h>
  38
  39 # ifndef I2C_GPIO_SYNC
  40 #  define I2C_GPIO_SYNC
  41 # endif
  42
  43 # ifndef I2C_INIT
  44 #  define I2C_INIT \
  45         do { \
  46                 gpio_request(CONFIG_SOFT_I2C_GPIO_SCL, "soft_i2c"); \
  47                 gpio_request(CONFIG_SOFT_I2C_GPIO_SDA, "soft_i2c"); \
  48         } while (0)
  49 # endif
  50
  51 # ifndef I2C_ACTIVE
  52 #  define I2C_ACTIVE do { } while (0)
  53 # endif
  54
  55 # ifndef I2C_TRISTATE
  56 #  define I2C_TRISTATE do { } while (0)
  57 # endif
  58
  59 # ifndef I2C_READ
  60 #  define I2C_READ gpio_get_value(CONFIG_SOFT_I2C_GPIO_SDA)
  61 # endif
  62
  63 # ifndef I2C_SDA
  64 #  define I2C_SDA(bit) \
  65         do { \
  66                 if (bit) \
  67                         gpio_direction_input(CONFIG_SOFT_I2C_GPIO_SDA); \
  68                 else \
  69                         gpio_direction_output(CONFIG_SOFT_I2C_GPIO_SDA, 0); \
  70                 I2C_GPIO_SYNC; \
  71         } while (0)
  72 # endif
  73
  74 # ifndef I2C_SCL
  75 #  define I2C_SCL(bit) \
  76         do { \
  77                 gpio_direction_output(CONFIG_SOFT_I2C_GPIO_SCL, bit); \
  78                 I2C_GPIO_SYNC; \
  79         } while (0)
  80 # endif
  81
  82 # ifndef I2C_DELAY
  83 #  define I2C_DELAY udelay(5)   /* 1/4 I2C clock duration */
  84 # endif
  85
  86 #endif
  87
  88 /* #define      DEBUG_I2C       */
  89
  90 DECLARE_GLOBAL_DATA_PTR;
  91
  92 #ifndef I2C_SOFT_DECLARATIONS
  93 #  define I2C_SOFT_DECLARATIONS
  94 #endif
  95
  96 #if !defined(CONFIG_SYS_I2C_SOFT_SPEED)
  97 #define CONFIG_SYS_I2C_SOFT_SPEED CONFIG_SYS_I2C_SPEED
  98 #endif
  99 #if !defined(CONFIG_SYS_I2C_SOFT_SLAVE)
 100 #define CONFIG_SYS_I2C_SOFT_SLAVE CONFIG_SYS_I2C_SLAVE
 101 #endif
 102
 103 /*-----------------------------------------------------------------------
 104  * Definitions
 105  */
 106 #define RETRIES         0
 107
 108 #define I2C_ACK         0               /* PD_SDA level to ack a byte */
 109 #define I2C_NOACK       1               /* PD_SDA level to noack a byte */
 110
 111
 112 #ifdef DEBUG_I2C
 113 #define PRINTD(fmt,args...)     do {    \
 114                 printf (fmt ,##args);   \
 115         } while (0)
 116 #else
 117 #define PRINTD(fmt,args...)
 118 #endif
 119
 120 /*-----------------------------------------------------------------------
 121  * Local functions
 122  */
 123 #if !defined(CONFIG_SYS_I2C_INIT_BOARD)
 124 static void  send_reset (void);
 125 #endif
 126 static void  send_start (void);
 127 static void  send_stop  (void);
 128 static void  send_ack   (int);
 129 static int   write_byte (uchar byte);
 130 static uchar read_byte  (int);
 131
 132 #if !defined(CONFIG_SYS_I2C_INIT_BOARD)
 133 /*-----------------------------------------------------------------------
 134  * Send a reset sequence consisting of 9 clocks with the data signal high
 135  * to clock any confused device back into an idle state.  Also send a
 136  * <stop> at the end of the sequence for belts & suspenders.
 137  */
 138 static void send_reset(void)
 139 {
 140         I2C_SOFT_DECLARATIONS   /* intentional without ';' */
 141         int j;
 142
 143         I2C_SCL(1);
 144         I2C_SDA(1);
 145 #ifdef  I2C_INIT
 146         I2C_INIT;
 147 #endif
 148         I2C_TRISTATE;
 149         for(j = 0; j < 9; j++) {
 150                 I2C_SCL(0);
 151                 I2C_DELAY;
 152                 I2C_DELAY;
 153                 I2C_SCL(1);
 154                 I2C_DELAY;
 155                 I2C_DELAY;
 156         }
 157         send_stop();
 158         I2C_TRISTATE;
 159 }
 160 #endif
 161
 162 /*-----------------------------------------------------------------------
 163  * START: High -> Low on SDA while SCL is High
 164  */
 165 static void send_start(void)
 166 {
 167         I2C_SOFT_DECLARATIONS   /* intentional without ';' */
 168
 169         I2C_DELAY;
 170         I2C_SDA(1);
 171         I2C_ACTIVE;
 172         I2C_DELAY;
 173         I2C_SCL(1);
 174         I2C_DELAY;
 175         I2C_SDA(0);
 176         I2C_DELAY;
 177 }
 178
 179 /*-----------------------------------------------------------------------
 180  * STOP: Low -> High on SDA while SCL is High
 181  */
 182 static void send_stop(void)
 183 {
 184         I2C_SOFT_DECLARATIONS   /* intentional without ';' */
 185
 186         I2C_SCL(0);
 187         I2C_DELAY;
 188         I2C_SDA(0);
 189         I2C_ACTIVE;
 190         I2C_DELAY;
 191         I2C_SCL(1);
 192         I2C_DELAY;
 193         I2C_SDA(1);
 194         I2C_DELAY;
 195         I2C_TRISTATE;
 196 }
 197
 198 /*-----------------------------------------------------------------------
 199  * ack should be I2C_ACK or I2C_NOACK
 200  */
 201 static void send_ack(int ack)
 202 {
 203         I2C_SOFT_DECLARATIONS   /* intentional without ';' */
 204
 205         I2C_SCL(0);
 206         I2C_DELAY;
 207         I2C_ACTIVE;
 208         I2C_SDA(ack);
 209         I2C_DELAY;
 210         I2C_SCL(1);
 211         I2C_DELAY;
 212         I2C_DELAY;
 213         I2C_SCL(0);
 214         I2C_DELAY;
 215 }
 216
 217 /*-----------------------------------------------------------------------
 218  * Send 8 bits and look for an acknowledgement.
 219  */
 220 static int write_byte(uchar data)
 221 {
 222         I2C_SOFT_DECLARATIONS   /* intentional without ';' */
 223         int j;
 224         int nack;
 225
 226         I2C_ACTIVE;
 227         for(j = 0; j < 8; j++) {
 228                 I2C_SCL(0);
 229                 I2C_DELAY;
 230                 I2C_SDA(data & 0x80);
 231                 I2C_DELAY;
 232                 I2C_SCL(1);
 233                 I2C_DELAY;
 234                 I2C_DELAY;
 235
 236                 data <<= 1;
 237         }
 238
 239         /*
 240          * Look for an <ACK>(negative logic) and return it.
 241          */
 242         I2C_SCL(0);
 243         I2C_DELAY;
 244         I2C_SDA(1);
 245         I2C_TRISTATE;
 246         I2C_DELAY;
 247         I2C_SCL(1);
 248         I2C_DELAY;
 249         I2C_DELAY;
 250         nack = I2C_READ;
 251         I2C_SCL(0);
 252         I2C_DELAY;
 253         I2C_ACTIVE;
 254
 255         return(nack);   /* not a nack is an ack */
 256 }
 257
 258 /*-----------------------------------------------------------------------
 259  * if ack == I2C_ACK, ACK the byte so can continue reading, else
 260  * send I2C_NOACK to end the read.
 261  */
 262 static uchar read_byte(int ack)
 263 {
 264         I2C_SOFT_DECLARATIONS   /* intentional without ';' */
 265         int  data;
 266         int  j;
 267
 268         /*
 269          * Read 8 bits, MSB first.
 270          */
 271         I2C_TRISTATE;
 272         I2C_SDA(1);
 273         data = 0;
 274         for(j = 0; j < 8; j++) {
 275                 I2C_SCL(0);
 276                 I2C_DELAY;
 277                 I2C_SCL(1);
 278                 I2C_DELAY;
 279                 data <<= 1;
 280                 data |= I2C_READ;
 281                 I2C_DELAY;
 282         }
 283         send_ack(ack);
 284
 285         return(data);
 286 }
 287
 288 /*-----------------------------------------------------------------------
 289  * Initialization
 290  */
 291 static void soft_i2c_init(struct i2c_adapter *adap, int speed, int slaveaddr)
 292 {
 293 #if defined(CONFIG_SYS_I2C_INIT_BOARD)
 294         /* call board specific i2c bus reset routine before accessing the   */
 295         /* environment, which might be in a chip on that bus. For details   */
 296         /* about this problem see doc/I2C_Edge_Conditions.                  */
 297         i2c_init_board();
 298 #else
 299         /*
 300          * WARNING: Do NOT save speed in a static variable: if the
 301          * I2C routines are called before RAM is initialized (to read
 302          * the DIMM SPD, for instance), RAM won't be usable and your
 303          * system will crash.
 304          */
 305         send_reset ();
 306 #endif
 307 }
 308
 309 /*-----------------------------------------------------------------------
 310  * Probe to see if a chip is present.  Also good for checking for the
 311  * completion of EEPROM writes since the chip stops responding until
 312  * the write completes (typically 10mSec).
 313  */
 314 static int soft_i2c_probe(struct i2c_adapter *adap, uint8_t addr)
 315 {
 316         int rc;
 317
 318         /*
 319          * perform 1 byte write transaction with just address byte
 320          * (fake write)
 321          */
 322         send_start();
 323         rc = write_byte ((addr << 1) | 0);
 324         send_stop();
 325
 326         return (rc ? 1 : 0);
 327 }
 328
 329 /*-----------------------------------------------------------------------
 330  * Read bytes
 331  */
 332 static int  soft_i2c_read(struct i2c_adapter *adap, uchar chip, uint addr,
 333                         int alen, uchar *buffer, int len)
 334 {
 335         int shift;
 336         PRINTD("i2c_read: chip %02X addr %02X alen %d buffer %p len %d\n",
 337                 chip, addr, alen, buffer, len);
 338
 339 #ifdef CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW
 340         /*
 341          * EEPROM chips that implement "address overflow" are ones
 342          * like Catalyst 24WC04/08/16 which has 9/10/11 bits of
 343          * address and the extra bits end up in the "chip address"
 344          * bit slots. This makes a 24WC08 (1Kbyte) chip look like
 345          * four 256 byte chips.
 346          *
 347          * Note that we consider the length of the address field to
 348          * still be one byte because the extra address bits are
 349          * hidden in the chip address.
 350          */
 351         chip |= ((addr >> (alen * 8)) & CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW);
 352
 353         PRINTD("i2c_read: fix addr_overflow: chip %02X addr %02X\n",
 354                 chip, addr);
 355 #endif
 356
 357         /*
 358          * Do the addressing portion of a write cycle to set the
 359          * chip's address pointer.  If the address length is zero,
 360          * don't do the normal write cycle to set the address pointer,
 361          * there is no address pointer in this chip.
 362          */
 363         send_start();
 364         if(alen > 0) {
 365                 if(write_byte(chip << 1)) {     /* write cycle */
 366                         send_stop();
 367                         PRINTD("i2c_read, no chip responded %02X\n", chip);
 368                         return(1);
 369                 }
 370                 shift = (alen-1) * 8;
 371                 while(alen-- > 0) {
 372                         if(write_byte(addr >> shift)) {
 373                                 PRINTD("i2c_read, address not <ACK>ed\n");
 374                                 return(1);
 375                         }
 376                         shift -= 8;
 377                 }
 378
 379                 /* Some I2C chips need a stop/start sequence here,
 380                  * other chips don't work with a full stop and need
 381                  * only a start.  Default behaviour is to send the
 382                  * stop/start sequence.
 383                  */
 384 #ifdef CONFIG_SOFT_I2C_READ_REPEATED_START
 385                 send_start();
 386 #else
 387                 send_stop();
 388                 send_start();
 389 #endif
 390         }
 391         /*
 392          * Send the chip address again, this time for a read cycle.
 393          * Then read the data.  On the last byte, we do a NACK instead
 394          * of an ACK(len == 0) to terminate the read.
 395          */
 396         write_byte((chip << 1) | 1);    /* read cycle */
 397         while(len-- > 0) {
 398                 *buffer++ = read_byte(len == 0);
 399         }
 400         send_stop();
 401         return(0);
 402 }
 403
 404 /*-----------------------------------------------------------------------
 405  * Write bytes
 406  */
 407 static int  soft_i2c_write(struct i2c_adapter *adap, uchar chip, uint addr,
 408                         int alen, uchar *buffer, int len)
 409 {
 410         int shift, failures = 0;
 411
 412         PRINTD("i2c_write: chip %02X addr %02X alen %d buffer %p len %d\n",
 413                 chip, addr, alen, buffer, len);
 414
 415         send_start();
 416         if(write_byte(chip << 1)) {     /* write cycle */
 417                 send_stop();
 418                 PRINTD("i2c_write, no chip responded %02X\n", chip);
 419                 return(1);
 420         }
 421         shift = (alen-1) * 8;
 422         while(alen-- > 0) {
 423                 if(write_byte(addr >> shift)) {
 424                         PRINTD("i2c_write, address not <ACK>ed\n");
 425                         return(1);
 426                 }
 427                 shift -= 8;
 428         }
 429
 430         while(len-- > 0) {
 431                 if(write_byte(*buffer++)) {
 432                         failures++;
 433                 }
 434         }
 435         send_stop();
 436         return(failures);
 437 }
 438
 439 /*
 440  * Register soft i2c adapters
 441  */
 442 U_BOOT_I2C_ADAP_COMPLETE(soft00, soft_i2c_init, soft_i2c_probe,
 443                          soft_i2c_read, soft_i2c_write, NULL,
 444                          CONFIG_SYS_I2C_SOFT_SPEED, CONFIG_SYS_I2C_SOFT_SLAVE,
 445                          0)
 446 #if defined(I2C_SOFT_DECLARATIONS2)
 447 U_BOOT_I2C_ADAP_COMPLETE(soft01, soft_i2c_init, soft_i2c_probe,
 448                          soft_i2c_read, soft_i2c_write, NULL,
 449                          CONFIG_SYS_I2C_SOFT_SPEED_2,
 450                          CONFIG_SYS_I2C_SOFT_SLAVE_2,
 451                          1)
 452 #endif
 453 #if defined(I2C_SOFT_DECLARATIONS3)
 454 U_BOOT_I2C_ADAP_COMPLETE(soft02, soft_i2c_init, soft_i2c_probe,
 455                          soft_i2c_read, soft_i2c_write, NULL,
 456                          CONFIG_SYS_I2C_SOFT_SPEED_3,
 457                          CONFIG_SYS_I2C_SOFT_SLAVE_3,
 458                          2)
 459 #endif
 460 #if defined(I2C_SOFT_DECLARATIONS4)
 461 U_BOOT_I2C_ADAP_COMPLETE(soft03, soft_i2c_init, soft_i2c_probe,
 462                          soft_i2c_read, soft_i2c_write, NULL,
 463                          CONFIG_SYS_I2C_SOFT_SPEED_4,
 464                          CONFIG_SYS_I2C_SOFT_SLAVE_4,
 465                          3)
 466 #endif
 467 #if defined(I2C_SOFT_DECLARATIONS5)
 468 U_BOOT_I2C_ADAP_COMPLETE(soft04, soft_i2c_init, soft_i2c_probe,
 469                          soft_i2c_read, soft_i2c_write, NULL,
 470                          CONFIG_SYS_I2C_SOFT_SPEED_5,
 471                          CONFIG_SYS_I2C_SOFT_SLAVE_5,
 472                          4)
 473 #endif
 474 #if defined(I2C_SOFT_DECLARATIONS6)
 475 U_BOOT_I2C_ADAP_COMPLETE(soft05, soft_i2c_init, soft_i2c_probe,
 476                          soft_i2c_read, soft_i2c_write, NULL,
 477                          CONFIG_SYS_I2C_SOFT_SPEED_6,
 478                          CONFIG_SYS_I2C_SOFT_SLAVE_6,
 479                          5)
 480 #endif
 481 #if defined(I2C_SOFT_DECLARATIONS7)
 482 U_BOOT_I2C_ADAP_COMPLETE(soft06, soft_i2c_init, soft_i2c_probe,
 483                          soft_i2c_read, soft_i2c_write, NULL,
 484                          CONFIG_SYS_I2C_SOFT_SPEED_7,
 485                          CONFIG_SYS_I2C_SOFT_SLAVE_7,
 486                          6)
 487 #endif
 488 #if defined(I2C_SOFT_DECLARATIONS8)
 489 U_BOOT_I2C_ADAP_COMPLETE(soft07, soft_i2c_init, soft_i2c_probe,
 490                          soft_i2c_read, soft_i2c_write, NULL,
 491                          CONFIG_SYS_I2C_SOFT_SPEED_8,
 492                          CONFIG_SYS_I2C_SOFT_SLAVE_8,
 493                          7)
 494 #endif
 495 #if defined(I2C_SOFT_DECLARATIONS9)
 496 U_BOOT_I2C_ADAP_COMPLETE(soft08, soft_i2c_init, soft_i2c_probe,
 497                          soft_i2c_read, soft_i2c_write, NULL,
 498                          CONFIG_SYS_I2C_SOFT_SPEED_9,
 499                          CONFIG_SYS_I2C_SOFT_SLAVE_9,
 500                          8)
 501 #endif
 502 #if defined(I2C_SOFT_DECLARATIONS10)
 503 U_BOOT_I2C_ADAP_COMPLETE(soft09, soft_i2c_init, soft_i2c_probe,
 504                          soft_i2c_read, soft_i2c_write, NULL,
 505                          CONFIG_SYS_I2C_SOFT_SPEED_10,
 506                          CONFIG_SYS_I2C_SOFT_SLAVE_10,
 507                          9)
 508 #endif
 509 #if defined(I2C_SOFT_DECLARATIONS11)
 510 U_BOOT_I2C_ADAP_COMPLETE(soft10, soft_i2c_init, soft_i2c_probe,
 511                          soft_i2c_read, soft_i2c_write, NULL,
 512                          CONFIG_SYS_I2C_SOFT_SPEED_11,
 513                          CONFIG_SYS_I2C_SOFT_SLAVE_11,
 514                          10)
 515 #endif
 516 #if defined(I2C_SOFT_DECLARATIONS12)
 517 U_BOOT_I2C_ADAP_COMPLETE(soft11, soft_i2c_init, soft_i2c_probe,
 518                          soft_i2c_read, soft_i2c_write, NULL,
 519                          CONFIG_SYS_I2C_SOFT_SPEED_12,
 520                          CONFIG_SYS_I2C_SOFT_SLAVE_12,
 521                          11)
 522 #endif