drivers/i2c/soft_i2c.c

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