arch/powerpc/cpu/mpc8260/i2c.c

   1 /*
   2  * (C) Copyright 2000
   3  * Paolo Scaffardi, AIRVENT SAM s.p.a - RIMINI(ITALY), arsenio@tin.it
   4  *
   5  * (C) Copyright 2000 Sysgo Real-Time Solutions, GmbH <www.elinos.com>
   6  * Marius Groeger <mgroeger@sysgo.de>
   7  *
   8  * SPDX-License-Identifier:     GPL-2.0+
   9  */
  10
  11 #include <common.h>
  12
  13 #if defined(CONFIG_HARD_I2C)
  14
  15 #include <asm/cpm_8260.h>
  16 #include <i2c.h>
  17
  18 DECLARE_GLOBAL_DATA_PTR;
  19
  20 #if defined(CONFIG_I2C_MULTI_BUS)
  21 static unsigned int i2c_bus_num __attribute__ ((section(".data"))) = 0;
  22 #endif /* CONFIG_I2C_MULTI_BUS */
  23
  24 /* uSec to wait between polls of the i2c */
  25 #define DELAY_US        100
  26 /* uSec to wait for the CPM to start processing the buffer */
  27 #define START_DELAY_US  1000
  28
  29 /*
  30  * tx/rx per-byte timeout: we delay DELAY_US uSec between polls so the
  31  * timeout will be (tx_length + rx_length) * DELAY_US * TOUT_LOOP
  32  */
  33 #define TOUT_LOOP 5
  34
  35 /*
  36  * Set default values
  37  */
  38 #ifndef CONFIG_SYS_I2C_SPEED
  39 #define CONFIG_SYS_I2C_SPEED    50000
  40 #endif
  41
  42
  43 typedef void (*i2c_ecb_t) (int, int, void *);   /* error callback function */
  44
  45 /* This structure keeps track of the bd and buffer space usage. */
  46 typedef struct i2c_state {
  47         int rx_idx;             /* index   to next free Rx BD */
  48         int tx_idx;             /* index   to next free Tx BD */
  49         void *rxbd;             /* pointer to next free Rx BD */
  50         void *txbd;             /* pointer to next free Tx BD */
  51         int tx_space;           /* number  of Tx bytes left   */
  52         unsigned char *tx_buf;  /* pointer to free Tx area    */
  53         i2c_ecb_t err_cb;       /* error callback function    */
  54         void *cb_data;          /* private data to be passed  */
  55 } i2c_state_t;
  56
  57 /* flags for i2c_send() and i2c_receive() */
  58 #define I2CF_ENABLE_SECONDARY   0x01    /* secondary_address is valid   */
  59 #define I2CF_START_COND         0x02    /* tx: generate start condition */
  60 #define I2CF_STOP_COND          0x04    /* tx: generate stop  condition */
  61
  62 /* return codes */
  63 #define I2CERR_NO_BUFFERS       1       /* no more BDs or buffer space  */
  64 #define I2CERR_MSG_TOO_LONG     2       /* tried to send/receive to much data */
  65 #define I2CERR_TIMEOUT          3       /* timeout in i2c_doio()        */
  66 #define I2CERR_QUEUE_EMPTY      4       /* i2c_doio called without send/rcv */
  67 #define I2CERR_IO_ERROR         5       /* had an error during comms    */
  68
  69 /* error callback flags */
  70 #define I2CECB_RX_ERR           0x10    /* this is a receive error      */
  71 #define     I2CECB_RX_OV        0x02    /* receive overrun error        */
  72 #define     I2CECB_RX_MASK      0x0f    /* mask for error bits          */
  73 #define I2CECB_TX_ERR           0x20    /* this is a transmit error     */
  74 #define     I2CECB_TX_CL        0x01    /* transmit collision error     */
  75 #define     I2CECB_TX_UN        0x02    /* transmit underflow error     */
  76 #define     I2CECB_TX_NAK       0x04    /* transmit no ack error        */
  77 #define     I2CECB_TX_MASK      0x0f    /* mask for error bits          */
  78 #define I2CECB_TIMEOUT          0x40    /* this is a timeout error      */
  79
  80 #define ERROR_I2C_NONE          0
  81 #define ERROR_I2C_LENGTH        1
  82
  83 #define I2C_WRITE_BIT           0x00
  84 #define I2C_READ_BIT            0x01
  85
  86 #define I2C_RXTX_LEN    128     /* maximum tx/rx buffer length */
  87
  88
  89 #define NUM_RX_BDS 4
  90 #define NUM_TX_BDS 4
  91 #define MAX_TX_SPACE 256
  92
  93 typedef struct I2C_BD {
  94         unsigned short status;
  95         unsigned short length;
  96         unsigned char *addr;
  97 } I2C_BD;
  98
  99 #define BD_I2C_TX_START 0x0400  /* special status for i2c: Start condition */
 100
 101 #define BD_I2C_TX_CL    0x0001  /* collision error */
 102 #define BD_I2C_TX_UN    0x0002  /* underflow error */
 103 #define BD_I2C_TX_NAK   0x0004  /* no acknowledge error */
 104 #define BD_I2C_TX_ERR   (BD_I2C_TX_NAK|BD_I2C_TX_UN|BD_I2C_TX_CL)
 105
 106 #define BD_I2C_RX_ERR   BD_SC_OV
 107
 108 /*
 109  * Returns the best value of I2BRG to meet desired clock speed of I2C with
 110  * input parameters (clock speed, filter, and predivider value).
 111  * It returns computer speed value and the difference between it and desired
 112  * speed.
 113  */
 114 static inline int
 115 i2c_roundrate(int hz, int speed, int filter, int modval,
 116               int *brgval, int *totspeed)
 117 {
 118         int moddiv = 1 << (5 - (modval & 3)), brgdiv, div;
 119
 120         debug("\t[I2C] trying hz=%d, speed=%d, filter=%d, modval=%d\n",
 121                 hz, speed, filter, modval);
 122
 123         div = moddiv * speed;
 124         brgdiv = (hz + div - 1) / div;
 125
 126         debug("\t\tmoddiv=%d, brgdiv=%d\n", moddiv, brgdiv);
 127
 128         *brgval = ((brgdiv + 1) / 2) - 3 - (2 * filter);
 129
 130         if ((*brgval < 0) || (*brgval > 255)) {
 131                 debug("\t\trejected brgval=%d\n", *brgval);
 132                 return -1;
 133         }
 134
 135         brgdiv = 2 * (*brgval + 3 + (2 * filter));
 136         div = moddiv * brgdiv;
 137         *totspeed = hz / div;
 138
 139         debug("\t\taccepted brgval=%d, totspeed=%d\n", *brgval, *totspeed);
 140
 141         return 0;
 142 }
 143
 144 /*
 145  * Sets the I2C clock predivider and divider to meet required clock speed.
 146  */
 147 static int i2c_setrate(int hz, int speed)
 148 {
 149         immap_t *immap = (immap_t *)CONFIG_SYS_IMMR;
 150         volatile i2c8260_t *i2c = (i2c8260_t *)&immap->im_i2c;
 151         int     brgval,
 152                 modval, /* 0-3 */
 153                 bestspeed_diff = speed,
 154                 bestspeed_brgval = 0,
 155                 bestspeed_modval = 0,
 156                 bestspeed_filter = 0,
 157                 totspeed,
 158                 filter = 0;     /* Use this fixed value */
 159
 160         for (modval = 0; modval < 4; modval++) {
 161                 if (i2c_roundrate(hz, speed, filter, modval, &brgval, &totspeed)
 162                     == 0) {
 163                         int diff = speed - totspeed;
 164
 165                         if ((diff >= 0) && (diff < bestspeed_diff)) {
 166                                 bestspeed_diff = diff;
 167                                 bestspeed_modval = modval;
 168                                 bestspeed_brgval = brgval;
 169                                 bestspeed_filter = filter;
 170                         }
 171                 }
 172         }
 173
 174         debug("[I2C] Best is:\n");
 175         debug("[I2C] CPU=%dhz RATE=%d F=%d I2MOD=%08x I2BRG=%08x DIFF=%dhz\n",
 176                 hz, speed, bestspeed_filter, bestspeed_modval, bestspeed_brgval,
 177                 bestspeed_diff);
 178
 179         i2c->i2c_i2mod |= ((bestspeed_modval & 3) << 1) |
 180                 (bestspeed_filter << 3);
 181         i2c->i2c_i2brg = bestspeed_brgval & 0xff;
 182
 183         debug("[I2C] i2mod=%08x i2brg=%08x\n", i2c->i2c_i2mod,
 184                 i2c->i2c_i2brg);
 185
 186         return 1;
 187 }
 188
 189 void i2c_init(int speed, int slaveadd)
 190 {
 191         volatile immap_t *immap = (immap_t *)CONFIG_SYS_IMMR;
 192         volatile cpm8260_t *cp = (cpm8260_t *)&immap->im_cpm;
 193         volatile i2c8260_t *i2c = (i2c8260_t *)&immap->im_i2c;
 194         volatile iic_t *iip;
 195         ulong rbase, tbase;
 196         volatile I2C_BD *rxbd, *txbd;
 197         uint dpaddr;
 198
 199 #ifdef CONFIG_SYS_I2C_INIT_BOARD
 200         /*
 201          * call board specific i2c bus reset routine before accessing the
 202          * environment, which might be in a chip on that bus. For details
 203          * about this problem see doc/I2C_Edge_Conditions.
 204          */
 205         i2c_init_board();
 206 #endif
 207
 208         dpaddr = immap->im_dprambase16[PROFF_I2C_BASE / sizeof(u16)];
 209         if (dpaddr == 0) {
 210                 /* need to allocate dual port ram */
 211                 dpaddr = m8260_cpm_dpalloc(64 +
 212                                         (NUM_RX_BDS * sizeof(I2C_BD)) +
 213                                         (NUM_TX_BDS * sizeof(I2C_BD)) +
 214                                         MAX_TX_SPACE, 64);
 215                 immap->im_dprambase16[PROFF_I2C_BASE / sizeof(u16)] =
 216                         dpaddr;
 217         }
 218
 219         /*
 220          * initialise data in dual port ram:
 221          *
 222          *        dpaddr -> parameter ram (64 bytes)
 223          *         rbase -> rx BD         (NUM_RX_BDS * sizeof(I2C_BD) bytes)
 224          *         tbase -> tx BD         (NUM_TX_BDS * sizeof(I2C_BD) bytes)
 225          *                  tx buffer     (MAX_TX_SPACE bytes)
 226          */
 227
 228         iip = (iic_t *)&immap->im_dprambase[dpaddr];
 229         memset((void *)iip, 0, sizeof(iic_t));
 230
 231         rbase = dpaddr + 64;
 232         tbase = rbase + NUM_RX_BDS * sizeof(I2C_BD);
 233
 234         /* Disable interrupts */
 235         i2c->i2c_i2mod = 0x00;
 236         i2c->i2c_i2cmr = 0x00;
 237         i2c->i2c_i2cer = 0xff;
 238         i2c->i2c_i2add = slaveadd;
 239
 240         /*
 241          * Set the I2C BRG Clock division factor from desired i2c rate
 242          * and current CPU rate (we assume sccr dfbgr field is 0;
 243          * divide BRGCLK by 1)
 244          */
 245         debug("[I2C] Setting rate...\n");
 246         i2c_setrate(gd->arch.brg_clk, CONFIG_SYS_I2C_SPEED);
 247
 248         /* Set I2C controller in master mode */
 249         i2c->i2c_i2com = 0x01;
 250
 251         /* Initialize Tx/Rx parameters */
 252         iip->iic_rbase = rbase;
 253         iip->iic_tbase = tbase;
 254         rxbd = (I2C_BD *)((unsigned char *) &immap->
 255                         im_dprambase[iip->iic_rbase]);
 256         txbd = (I2C_BD *)((unsigned char *) &immap->
 257                         im_dprambase[iip->iic_tbase]);
 258
 259         debug("[I2C] rbase = %04x\n", iip->iic_rbase);
 260         debug("[I2C] tbase = %04x\n", iip->iic_tbase);
 261         debug("[I2C] rxbd = %08x\n", (int) rxbd);
 262         debug("[I2C] txbd = %08x\n", (int) txbd);
 263
 264         /* Set big endian byte order */
 265         iip->iic_tfcr = 0x10;
 266         iip->iic_rfcr = 0x10;
 267
 268         /* Set maximum receive size. */
 269         iip->iic_mrblr = I2C_RXTX_LEN;
 270
 271         cp->cp_cpcr = mk_cr_cmd(CPM_CR_I2C_PAGE,
 272                                 CPM_CR_I2C_SBLOCK,
 273                                 0x00, CPM_CR_INIT_TRX) | CPM_CR_FLG;
 274         do {
 275                 __asm__ __volatile__("eieio");
 276         } while (cp->cp_cpcr & CPM_CR_FLG);
 277
 278         /* Clear events and interrupts */
 279         i2c->i2c_i2cer = 0xff;
 280         i2c->i2c_i2cmr = 0x00;
 281 }
 282
 283 static
 284 void i2c_newio(i2c_state_t *state)
 285 {
 286         volatile immap_t *immap = (immap_t *)CONFIG_SYS_IMMR;
 287         volatile iic_t *iip;
 288         uint dpaddr;
 289
 290         debug("[I2C] i2c_newio\n");
 291
 292         dpaddr = immap->im_dprambase16[PROFF_I2C_BASE / sizeof(u16)];
 293         iip = (iic_t *)&immap->im_dprambase[dpaddr];
 294         state->rx_idx = 0;
 295         state->tx_idx = 0;
 296         state->rxbd = (void *)&immap->im_dprambase[iip->iic_rbase];
 297         state->txbd = (void *)&immap->im_dprambase[iip->iic_tbase];
 298         state->tx_space = MAX_TX_SPACE;
 299         state->tx_buf = (uchar *)state->txbd + NUM_TX_BDS * sizeof(I2C_BD);
 300         state->err_cb = NULL;
 301         state->cb_data = NULL;
 302
 303         debug("[I2C] rxbd = %08x\n", (int)state->rxbd);
 304         debug("[I2C] txbd = %08x\n", (int)state->txbd);
 305         debug("[I2C] tx_buf = %08x\n", (int)state->tx_buf);
 306
 307         /* clear the buffer memory */
 308         memset((char *) state->tx_buf, 0, MAX_TX_SPACE);
 309 }
 310
 311 static
 312 int i2c_send(i2c_state_t *state,
 313              unsigned char address,
 314              unsigned char secondary_address,
 315              unsigned int flags, unsigned short size, unsigned char *dataout)
 316 {
 317         volatile I2C_BD *txbd;
 318         int i, j;
 319
 320         debug("[I2C] i2c_send add=%02d sec=%02d flag=%02d size=%d\n",
 321                 address, secondary_address, flags, size);
 322
 323         /* trying to send message larger than BD */
 324         if (size > I2C_RXTX_LEN)
 325                 return I2CERR_MSG_TOO_LONG;
 326
 327         /* no more free bds */
 328         if (state->tx_idx >= NUM_TX_BDS || state->tx_space < (2 + size))
 329                 return I2CERR_NO_BUFFERS;
 330
 331         txbd = (I2C_BD *)state->txbd;
 332         txbd->addr = state->tx_buf;
 333
 334         debug("[I2C] txbd = %08x\n", (int) txbd);
 335
 336         if (flags & I2CF_START_COND) {
 337                 debug("[I2C] Formatting addresses...\n");
 338                 if (flags & I2CF_ENABLE_SECONDARY) {
 339                         /* Length of message plus dest addresses */
 340                         txbd->length = size + 2;
 341                         txbd->addr[0] = address << 1;
 342                         txbd->addr[1] = secondary_address;
 343                         i = 2;
 344                 } else {
 345                         /* Length of message plus dest address */
 346                         txbd->length = size + 1;
 347                         /* Write destination address to BD */
 348                         txbd->addr[0] = address << 1;
 349                         i = 1;
 350                 }
 351         } else {
 352                 txbd->length = size;    /* Length of message */
 353                 i = 0;
 354         }
 355
 356         /* set up txbd */
 357         txbd->status = BD_SC_READY;
 358         if (flags & I2CF_START_COND)
 359                 txbd->status |= BD_I2C_TX_START;
 360         if (flags & I2CF_STOP_COND)
 361                 txbd->status |= BD_SC_LAST | BD_SC_WRAP;
 362
 363         /* Copy data to send into buffer */
 364         debug("[I2C] copy data...\n");
 365         for (j = 0; j < size; i++, j++)
 366                 txbd->addr[i] = dataout[j];
 367
 368         debug("[I2C] txbd: length=0x%04x status=0x%04x addr[0]=0x%02x addr[1]=0x%02x\n",
 369                 txbd->length, txbd->status, txbd->addr[0], txbd->addr[1]);
 370
 371         /* advance state */
 372         state->tx_buf += txbd->length;
 373         state->tx_space -= txbd->length;
 374         state->tx_idx++;
 375         state->txbd = (void *) (txbd + 1);
 376
 377         return 0;
 378 }
 379
 380 static
 381 int i2c_receive(i2c_state_t *state,
 382                 unsigned char address,
 383                 unsigned char secondary_address,
 384                 unsigned int flags,
 385                 unsigned short size_to_expect, unsigned char *datain)
 386 {
 387         volatile I2C_BD *rxbd, *txbd;
 388
 389         debug("[I2C] i2c_receive %02d %02d %02d\n", address,
 390                 secondary_address, flags);
 391
 392         /* Expected to receive too much */
 393         if (size_to_expect > I2C_RXTX_LEN)
 394                 return I2CERR_MSG_TOO_LONG;
 395
 396         /* no more free bds */
 397         if (state->tx_idx >= NUM_TX_BDS || state->rx_idx >= NUM_RX_BDS
 398             || state->tx_space < 2)
 399                 return I2CERR_NO_BUFFERS;
 400
 401         rxbd = (I2C_BD *) state->rxbd;
 402         txbd = (I2C_BD *) state->txbd;
 403
 404         debug("[I2C] rxbd = %08x\n", (int) rxbd);
 405         debug("[I2C] txbd = %08x\n", (int) txbd);
 406
 407         txbd->addr = state->tx_buf;
 408
 409         /* set up TXBD for destination address */
 410         if (flags & I2CF_ENABLE_SECONDARY) {
 411                 txbd->length = 2;
 412                 txbd->addr[0] = address << 1;   /* Write data */
 413                 txbd->addr[1] = secondary_address;      /* Internal address */
 414                 txbd->status = BD_SC_READY;
 415         } else {
 416                 txbd->length = 1 + size_to_expect;
 417                 txbd->addr[0] = (address << 1) | 0x01;
 418                 txbd->status = BD_SC_READY;
 419                 memset(&txbd->addr[1], 0, txbd->length);
 420         }
 421
 422         /* set up rxbd for reception */
 423         rxbd->status = BD_SC_EMPTY;
 424         rxbd->length = size_to_expect;
 425         rxbd->addr = datain;
 426
 427         txbd->status |= BD_I2C_TX_START;
 428         if (flags & I2CF_STOP_COND) {
 429                 txbd->status |= BD_SC_LAST | BD_SC_WRAP;
 430                 rxbd->status |= BD_SC_WRAP;
 431         }
 432
 433         debug("[I2C] txbd: length=0x%04x status=0x%04x addr[0]=0x%02x addr[1]=0x%02x\n",
 434                 txbd->length, txbd->status, txbd->addr[0], txbd->addr[1]);
 435         debug("[I2C] rxbd: length=0x%04x status=0x%04x addr[0]=0x%02x addr[1]=0x%02x\n",
 436                 rxbd->length, rxbd->status, rxbd->addr[0], rxbd->addr[1]);
 437
 438         /* advance state */
 439         state->tx_buf += txbd->length;
 440         state->tx_space -= txbd->length;
 441         state->tx_idx++;
 442         state->txbd = (void *) (txbd + 1);
 443         state->rx_idx++;
 444         state->rxbd = (void *) (rxbd + 1);
 445
 446         return 0;
 447 }
 448
 449
 450 static
 451 int i2c_doio(i2c_state_t *state)
 452 {
 453         volatile immap_t *immap = (immap_t *)CONFIG_SYS_IMMR;
 454         volatile iic_t *iip;
 455         volatile i2c8260_t *i2c = (i2c8260_t *)&immap->im_i2c;
 456         volatile I2C_BD *txbd, *rxbd;
 457         int n, i, b, rxcnt = 0, rxtimeo = 0, txcnt = 0, txtimeo = 0, rc = 0;
 458         uint dpaddr;
 459
 460         debug("[I2C] i2c_doio\n");
 461
 462         if (state->tx_idx <= 0 && state->rx_idx <= 0) {
 463                 debug("[I2C] No I/O is queued\n");
 464                 return I2CERR_QUEUE_EMPTY;
 465         }
 466
 467         dpaddr = immap->im_dprambase16[PROFF_I2C_BASE / sizeof(u16)];
 468         iip = (iic_t *)&immap->im_dprambase[dpaddr];
 469         iip->iic_rbptr = iip->iic_rbase;
 470         iip->iic_tbptr = iip->iic_tbase;
 471
 472         /* Enable I2C */
 473         debug("[I2C] Enabling I2C...\n");
 474         i2c->i2c_i2mod |= 0x01;
 475
 476         /* Begin transmission */
 477         i2c->i2c_i2com |= 0x80;
 478
 479         /* Loop until transmit & receive completed */
 480
 481         n = state->tx_idx;
 482
 483         if (n > 0) {
 484
 485                 txbd = ((I2C_BD *) state->txbd) - n;
 486                 for (i = 0; i < n; i++) {
 487                         txtimeo += TOUT_LOOP * txbd->length;
 488                         txbd++;
 489                 }
 490
 491                 txbd--;         /* wait until last in list is done */
 492
 493                 debug("[I2C] Transmitting...(txbd=0x%08lx)\n",
 494                         (ulong) txbd);
 495
 496                 udelay(START_DELAY_US); /* give it time to start */
 497                 while ((txbd->status & BD_SC_READY) && (++txcnt < txtimeo)) {
 498                         udelay(DELAY_US);
 499                         if (ctrlc())
 500                                 return -1;
 501                         __asm__ __volatile__("eieio");
 502                 }
 503         }
 504
 505         n = state->rx_idx;
 506
 507         if (txcnt < txtimeo && n > 0) {
 508
 509                 rxbd = ((I2C_BD *) state->rxbd) - n;
 510                 for (i = 0; i < n; i++) {
 511                         rxtimeo += TOUT_LOOP * rxbd->length;
 512                         rxbd++;
 513                 }
 514
 515                 rxbd--;         /* wait until last in list is done */
 516
 517                 debug("[I2C] Receiving...(rxbd=0x%08lx)\n", (ulong) rxbd);
 518
 519                 udelay(START_DELAY_US); /* give it time to start */
 520                 while ((rxbd->status & BD_SC_EMPTY) && (++rxcnt < rxtimeo)) {
 521                         udelay(DELAY_US);
 522                         if (ctrlc())
 523                                 return -1;
 524                         __asm__ __volatile__("eieio");
 525                 }
 526         }
 527
 528         /* Turn off I2C */
 529         i2c->i2c_i2mod &= ~0x01;
 530
 531         n = state->tx_idx;
 532
 533         if (n > 0) {
 534                 for (i = 0; i < n; i++) {
 535                         txbd = ((I2C_BD *) state->txbd) - (n - i);
 536                         b = txbd->status & BD_I2C_TX_ERR;
 537                         if (b != 0) {
 538                                 if (state->err_cb != NULL)
 539                                         (*state->err_cb) (I2CECB_TX_ERR | b,
 540                                                           i, state->cb_data);
 541                                 if (rc == 0)
 542                                         rc = I2CERR_IO_ERROR;
 543                         }
 544                 }
 545         }
 546
 547         n = state->rx_idx;
 548
 549         if (n > 0) {
 550                 for (i = 0; i < n; i++) {
 551                         rxbd = ((I2C_BD *) state->rxbd) - (n - i);
 552                         b = rxbd->status & BD_I2C_RX_ERR;
 553                         if (b != 0) {
 554                                 if (state->err_cb != NULL)
 555                                         (*state->err_cb) (I2CECB_RX_ERR | b,
 556                                                           i, state->cb_data);
 557                                 if (rc == 0)
 558                                         rc = I2CERR_IO_ERROR;
 559                         }
 560                 }
 561         }
 562
 563         if ((txtimeo > 0 && txcnt >= txtimeo) ||
 564             (rxtimeo > 0 && rxcnt >= rxtimeo)) {
 565                 if (state->err_cb != NULL)
 566                         (*state->err_cb) (I2CECB_TIMEOUT, -1, state->cb_data);
 567                 if (rc == 0)
 568                         rc = I2CERR_TIMEOUT;
 569         }
 570
 571         return rc;
 572 }
 573
 574 static void i2c_probe_callback(int flags, int xnum, void *data)
 575 {
 576         /*
 577          * the only acceptable errors are a transmit NAK or a receive
 578          * overrun - tx NAK means the device does not exist, rx OV
 579          * means the device must have responded to the slave address
 580          * even though the transfer failed
 581          */
 582         if (flags == (I2CECB_TX_ERR | I2CECB_TX_NAK))
 583                 *(int *) data |= 1;
 584         if (flags == (I2CECB_RX_ERR | I2CECB_RX_OV))
 585                 *(int *) data |= 2;
 586 }
 587
 588 int i2c_probe(uchar chip)
 589 {
 590         i2c_state_t state;
 591         int rc, err_flag;
 592         uchar buf[1];
 593
 594         i2c_newio(&state);
 595
 596         state.err_cb = i2c_probe_callback;
 597         state.cb_data = (void *) &err_flag;
 598         err_flag = 0;
 599
 600         rc = i2c_receive(&state, chip, 0, I2CF_START_COND | I2CF_STOP_COND, 1,
 601                          buf);
 602
 603         if (rc != 0)
 604                 return rc;      /* probe failed */
 605
 606         rc = i2c_doio(&state);
 607
 608         if (rc == 0)
 609                 return 0;       /* device exists - read succeeded */
 610
 611         if (rc == I2CERR_TIMEOUT)
 612                 return -1;      /* device does not exist - timeout */
 613
 614         if (rc != I2CERR_IO_ERROR || err_flag == 0)
 615                 return rc;      /* probe failed */
 616
 617         if (err_flag & 1)
 618                 return -1;      /* device does not exist - had transmit NAK */
 619
 620         return 0;               /* device exists - had receive overrun */
 621 }
 622
 623
 624 int i2c_read(uchar chip, uint addr, int alen, uchar *buffer, int len)
 625 {
 626         i2c_state_t state;
 627         uchar xaddr[4];
 628         int rc;
 629
 630         xaddr[0] = (addr >> 24) & 0xFF;
 631         xaddr[1] = (addr >> 16) & 0xFF;
 632         xaddr[2] = (addr >> 8) & 0xFF;
 633         xaddr[3] = addr & 0xFF;
 634
 635 #ifdef CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW
 636         /*
 637          * EEPROM chips that implement "address overflow" are ones
 638          * like Catalyst 24WC04/08/16 which has 9/10/11 bits of address
 639          * and the extra bits end up in the "chip address" bit slots.
 640          * This makes a 24WC08 (1Kbyte) chip look like four 256 byte
 641          * chips.
 642          *
 643          * Note that we consider the length of the address field to still
 644          * be one byte because the extra address bits are hidden in the
 645          * chip address.
 646          */
 647         chip |= ((addr >> (alen * 8)) & CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW);
 648 #endif
 649
 650         i2c_newio(&state);
 651
 652         rc = i2c_send(&state, chip, 0, I2CF_START_COND, alen,
 653                       &xaddr[4 - alen]);
 654         if (rc != 0) {
 655                 printf("i2c_read: i2c_send failed (%d)\n", rc);
 656                 return 1;
 657         }
 658
 659         rc = i2c_receive(&state, chip, 0, I2CF_STOP_COND, len, buffer);
 660         if (rc != 0) {
 661                 printf("i2c_read: i2c_receive failed (%d)\n", rc);
 662                 return 1;
 663         }
 664
 665         rc = i2c_doio(&state);
 666         if (rc != 0) {
 667                 printf("i2c_read: i2c_doio failed (%d)\n", rc);
 668                 return 1;
 669         }
 670         return 0;
 671 }
 672
 673 int i2c_write(uchar chip, uint addr, int alen, uchar *buffer, int len)
 674 {
 675         i2c_state_t state;
 676         uchar xaddr[4];
 677         int rc;
 678
 679         xaddr[0] = (addr >> 24) & 0xFF;
 680         xaddr[1] = (addr >> 16) & 0xFF;
 681         xaddr[2] = (addr >> 8) & 0xFF;
 682         xaddr[3] = addr & 0xFF;
 683
 684 #ifdef CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW
 685         /*
 686          * EEPROM chips that implement "address overflow" are ones
 687          * like Catalyst 24WC04/08/16 which has 9/10/11 bits of address
 688          * and the extra bits end up in the "chip address" bit slots.
 689          * This makes a 24WC08 (1Kbyte) chip look like four 256 byte
 690          * chips.
 691          *
 692          * Note that we consider the length of the address field to still
 693          * be one byte because the extra address bits are hidden in the
 694          * chip address.
 695          */
 696         chip |= ((addr >> (alen * 8)) & CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW);
 697 #endif
 698
 699         i2c_newio(&state);
 700
 701         rc = i2c_send(&state, chip, 0, I2CF_START_COND, alen,
 702                       &xaddr[4 - alen]);
 703         if (rc != 0) {
 704                 printf("i2c_write: first i2c_send failed (%d)\n", rc);
 705                 return 1;
 706         }
 707
 708         rc = i2c_send(&state, 0, 0, I2CF_STOP_COND, len, buffer);
 709         if (rc != 0) {
 710                 printf("i2c_write: second i2c_send failed (%d)\n", rc);
 711                 return 1;
 712         }
 713
 714         rc = i2c_doio(&state);
 715         if (rc != 0) {
 716                 printf("i2c_write: i2c_doio failed (%d)\n", rc);
 717                 return 1;
 718         }
 719         return 0;
 720 }
 721
 722 #if defined(CONFIG_I2C_MULTI_BUS)
 723 /*
 724  * Functions for multiple I2C bus handling
 725  */
 726 unsigned int i2c_get_bus_num(void)
 727 {
 728         return i2c_bus_num;
 729 }
 730
 731 int i2c_set_bus_num(unsigned int bus)
 732 {
 733         if (bus >= CONFIG_SYS_MAX_I2C_BUS)
 734                 return -1;
 735         i2c_bus_num = bus;
 736         return 0;
 737 }
 738
 739 #endif /* CONFIG_I2C_MULTI_BUS */
 740 #endif /* CONFIG_HARD_I2C */