drivers/i2c/omap24xx_i2c.c

   1 /*
   2  * Basic I2C functions
   3  *
   4  * Copyright (c) 2004 Texas Instruments
   5  *
   6  * This package is free software;  you can redistribute it and/or
   7  * modify it under the terms of the license found in the file
   8  * named COPYING that should have accompanied this file.
   9  *
  10  * THIS PACKAGE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
  11  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
  12  * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  13  *
  14  * Author: Jian Zhang jzhang@ti.com, Texas Instruments
  15  *
  16  * Copyright (c) 2003 Wolfgang Denk, wd@denx.de
  17  * Rewritten to fit into the current U-Boot framework
  18  *
  19  * Adapted for OMAP2420 I2C, r-woodruff2@ti.com
  20  *
  21  */
  22
  23 #include <common.h>
  24
  25 #include <asm/arch/i2c.h>
  26 #include <asm/io.h>
  27
  28 #include "omap24xx_i2c.h"
  29
  30 DECLARE_GLOBAL_DATA_PTR;
  31
  32 #define I2C_TIMEOUT     1000
  33
  34 static void wait_for_bb(void);
  35 static u16 wait_for_pin(void);
  36 static void flush_fifo(void);
  37
  38 /*
  39  * For SPL boot some boards need i2c before SDRAM is initialised so force
  40  * variables to live in SRAM
  41  */
  42 static struct i2c __attribute__((section (".data"))) *i2c_base =
  43                                         (struct i2c *)I2C_DEFAULT_BASE;
  44 static unsigned int __attribute__((section (".data"))) bus_initialized[I2C_BUS_MAX] =
  45                                         { [0 ... (I2C_BUS_MAX-1)] = 0 };
  46 static unsigned int __attribute__((section (".data"))) current_bus = 0;
  47
  48 void i2c_init(int speed, int slaveadd)
  49 {
  50         int psc, fsscll, fssclh;
  51         int hsscll = 0, hssclh = 0;
  52         u32 scll, sclh;
  53         int timeout = I2C_TIMEOUT;
  54
  55         /* Only handle standard, fast and high speeds */
  56         if ((speed != OMAP_I2C_STANDARD) &&
  57             (speed != OMAP_I2C_FAST_MODE) &&
  58             (speed != OMAP_I2C_HIGH_SPEED)) {
  59                 printf("Error : I2C unsupported speed %d\n", speed);
  60                 return;
  61         }
  62
  63         psc = I2C_IP_CLK / I2C_INTERNAL_SAMPLING_CLK;
  64         psc -= 1;
  65         if (psc < I2C_PSC_MIN) {
  66                 printf("Error : I2C unsupported prescalar %d\n", psc);
  67                 return;
  68         }
  69
  70         if (speed == OMAP_I2C_HIGH_SPEED) {
  71                 /* High speed */
  72
  73                 /* For first phase of HS mode */
  74                 fsscll = fssclh = I2C_INTERNAL_SAMPLING_CLK /
  75                         (2 * OMAP_I2C_FAST_MODE);
  76
  77                 fsscll -= I2C_HIGHSPEED_PHASE_ONE_SCLL_TRIM;
  78                 fssclh -= I2C_HIGHSPEED_PHASE_ONE_SCLH_TRIM;
  79                 if (((fsscll < 0) || (fssclh < 0)) ||
  80                     ((fsscll > 255) || (fssclh > 255))) {
  81                         puts("Error : I2C initializing first phase clock\n");
  82                         return;
  83                 }
  84
  85                 /* For second phase of HS mode */
  86                 hsscll = hssclh = I2C_INTERNAL_SAMPLING_CLK / (2 * speed);
  87
  88                 hsscll -= I2C_HIGHSPEED_PHASE_TWO_SCLL_TRIM;
  89                 hssclh -= I2C_HIGHSPEED_PHASE_TWO_SCLH_TRIM;
  90                 if (((fsscll < 0) || (fssclh < 0)) ||
  91                     ((fsscll > 255) || (fssclh > 255))) {
  92                         puts("Error : I2C initializing second phase clock\n");
  93                         return;
  94                 }
  95
  96                 scll = (unsigned int)hsscll << 8 | (unsigned int)fsscll;
  97                 sclh = (unsigned int)hssclh << 8 | (unsigned int)fssclh;
  98
  99         } else {
 100                 /* Standard and fast speed */
 101                 fsscll = fssclh = I2C_INTERNAL_SAMPLING_CLK / (2 * speed);
 102
 103                 fsscll -= I2C_FASTSPEED_SCLL_TRIM;
 104                 fssclh -= I2C_FASTSPEED_SCLH_TRIM;
 105                 if (((fsscll < 0) || (fssclh < 0)) ||
 106                     ((fsscll > 255) || (fssclh > 255))) {
 107                         puts("Error : I2C initializing clock\n");
 108                         return;
 109                 }
 110
 111                 scll = (unsigned int)fsscll;
 112                 sclh = (unsigned int)fssclh;
 113         }
 114
 115         if (readw(&i2c_base->con) & I2C_CON_EN) {
 116                 writew(0, &i2c_base->con);
 117                 udelay(50000);
 118         }
 119
 120         writew(0x2, &i2c_base->sysc); /* for ES2 after soft reset */
 121         udelay(1000);
 122
 123         writew(I2C_CON_EN, &i2c_base->con);
 124         while (!(readw(&i2c_base->syss) & I2C_SYSS_RDONE) && timeout--) {
 125                 if (timeout <= 0) {
 126                         puts("ERROR: Timeout in soft-reset\n");
 127                         return;
 128                 }
 129                 udelay(1000);
 130         }
 131
 132         writew(0, &i2c_base->con);
 133         writew(psc, &i2c_base->psc);
 134         writew(scll, &i2c_base->scll);
 135         writew(sclh, &i2c_base->sclh);
 136
 137         /* own address */
 138         writew(slaveadd, &i2c_base->oa);
 139         writew(I2C_CON_EN, &i2c_base->con);
 140
 141         /* have to enable intrrupts or OMAP i2c module doesn't work */
 142         writew(I2C_IE_XRDY_IE | I2C_IE_RRDY_IE | I2C_IE_ARDY_IE |
 143                 I2C_IE_NACK_IE | I2C_IE_AL_IE, &i2c_base->ie);
 144         udelay(1000);
 145         flush_fifo();
 146         writew(0xFFFF, &i2c_base->stat);
 147         writew(0, &i2c_base->cnt);
 148
 149         if (gd->flags & GD_FLG_RELOC)
 150                 bus_initialized[current_bus] = 1;
 151 }
 152
 153 static int i2c_read_byte(u8 devaddr, u16 regoffset, u8 alen, u8 *value)
 154 {
 155         int i2c_error = 0;
 156         u16 status;
 157         int i = 2 - alen;
 158         u8 tmpbuf[2] = {(regoffset) >> 8, regoffset & 0xff};
 159         u16 w;
 160
 161         /* wait until bus not busy */
 162         wait_for_bb();
 163
 164         /* one byte only */
 165         writew(alen, &i2c_base->cnt);
 166         /* set slave address */
 167         writew(devaddr, &i2c_base->sa);
 168         /* no stop bit needed here */
 169         writew(I2C_CON_EN | I2C_CON_MST | I2C_CON_STT |
 170               I2C_CON_TRX, &i2c_base->con);
 171
 172         /* send register offset */
 173         while (1) {
 174                 status = wait_for_pin();
 175                 if (status == 0 || status & I2C_STAT_NACK) {
 176                         i2c_error = 1;
 177                         goto read_exit;
 178                 }
 179                 if (status & I2C_STAT_XRDY) {
 180                         w = tmpbuf[i++];
 181 #if !(defined(CONFIG_OMAP243X) || defined(CONFIG_OMAP34XX) || \
 182         defined(CONFIG_OMAP44XX) || defined(CONFIG_AM33XX) || \
 183         defined(CONFIG_OMAP54XX))
 184                         w |= tmpbuf[i++] << 8;
 185 #endif
 186                         writew(w, &i2c_base->data);
 187                         writew(I2C_STAT_XRDY, &i2c_base->stat);
 188                 }
 189                 if (status & I2C_STAT_ARDY) {
 190                         writew(I2C_STAT_ARDY, &i2c_base->stat);
 191                         break;
 192                 }
 193         }
 194
 195         /* set slave address */
 196         writew(devaddr, &i2c_base->sa);
 197         /* read one byte from slave */
 198         writew(1, &i2c_base->cnt);
 199         /* need stop bit here */
 200         writew(I2C_CON_EN | I2C_CON_MST |
 201                 I2C_CON_STT | I2C_CON_STP,
 202                 &i2c_base->con);
 203
 204         /* receive data */
 205         while (1) {
 206                 status = wait_for_pin();
 207                 if (status == 0 || status & I2C_STAT_NACK) {
 208                         i2c_error = 1;
 209                         goto read_exit;
 210                 }
 211                 if (status & I2C_STAT_RRDY) {
 212 #if defined(CONFIG_OMAP243X) || defined(CONFIG_OMAP34XX) || \
 213         defined(CONFIG_OMAP44XX) || defined(CONFIG_AM33XX) || \
 214         defined(CONFIG_OMAP54XX)
 215                         *value = readb(&i2c_base->data);
 216 #else
 217                         *value = readw(&i2c_base->data);
 218 #endif
 219                         writew(I2C_STAT_RRDY, &i2c_base->stat);
 220                 }
 221                 if (status & I2C_STAT_ARDY) {
 222                         writew(I2C_STAT_ARDY, &i2c_base->stat);
 223                         break;
 224                 }
 225         }
 226
 227 read_exit:
 228         flush_fifo();
 229         writew(0xFFFF, &i2c_base->stat);
 230         writew(0, &i2c_base->cnt);
 231         return i2c_error;
 232 }
 233
 234 static void flush_fifo(void)
 235 {       u16 stat;
 236
 237         /* note: if you try and read data when its not there or ready
 238          * you get a bus error
 239          */
 240         while (1) {
 241                 stat = readw(&i2c_base->stat);
 242                 if (stat == I2C_STAT_RRDY) {
 243 #if defined(CONFIG_OMAP243X) || defined(CONFIG_OMAP34XX) || \
 244         defined(CONFIG_OMAP44XX) || defined(CONFIG_AM33XX) || \
 245         defined(CONFIG_OMAP54XX)
 246                         readb(&i2c_base->data);
 247 #else
 248                         readw(&i2c_base->data);
 249 #endif
 250                         writew(I2C_STAT_RRDY, &i2c_base->stat);
 251                         udelay(1000);
 252                 } else
 253                         break;
 254         }
 255 }
 256
 257 int i2c_probe(uchar chip)
 258 {
 259         u16 status;
 260         int res = 1; /* default = fail */
 261
 262         if (chip == readw(&i2c_base->oa))
 263                 return res;
 264
 265         /* wait until bus not busy */
 266         wait_for_bb();
 267
 268         /* try to read one byte */
 269         writew(1, &i2c_base->cnt);
 270         /* set slave address */
 271         writew(chip, &i2c_base->sa);
 272         /* stop bit needed here */
 273         writew (I2C_CON_EN | I2C_CON_MST | I2C_CON_STT | I2C_CON_STP, &i2c_base->con);
 274
 275         while (1) {
 276                 status = wait_for_pin();
 277                 if (status == 0 || status & I2C_STAT_AL) {
 278                         res = 1;
 279                         goto probe_exit;
 280                 }
 281                 if (status & I2C_STAT_NACK) {
 282                         res = 1;
 283                         writew(0xff, &i2c_base->stat);
 284                         writew (readw (&i2c_base->con) | I2C_CON_STP, &i2c_base->con);
 285                         wait_for_bb ();
 286                         break;
 287                 }
 288                 if (status & I2C_STAT_ARDY) {
 289                         writew(I2C_STAT_ARDY, &i2c_base->stat);
 290                         break;
 291                 }
 292                 if (status & I2C_STAT_RRDY) {
 293                         res = 0;
 294 #if defined(CONFIG_OMAP243X) || defined(CONFIG_OMAP34XX) || \
 295         defined(CONFIG_OMAP44XX) || defined(CONFIG_AM33XX) || \
 296         defined(CONFIG_OMAP54XX)
 297                         readb(&i2c_base->data);
 298 #else
 299                         readw(&i2c_base->data);
 300 #endif
 301                         writew(I2C_STAT_RRDY, &i2c_base->stat);
 302                 }
 303         }
 304
 305 probe_exit:
 306         flush_fifo();
 307         /* don't allow any more data in... we don't want it. */
 308         writew(0, &i2c_base->cnt);
 309         writew(0xFFFF, &i2c_base->stat);
 310         return res;
 311 }
 312
 313 int i2c_read(uchar chip, uint addr, int alen, uchar *buffer, int len)
 314 {
 315         int i;
 316
 317         if (alen > 2) {
 318                 printf("I2C read: addr len %d not supported\n", alen);
 319                 return 1;
 320         }
 321
 322         if (addr + len > (1 << 16)) {
 323                 puts("I2C read: address out of range\n");
 324                 return 1;
 325         }
 326
 327         for (i = 0; i < len; i++) {
 328                 if (i2c_read_byte(chip, addr + i, alen, &buffer[i])) {
 329                         puts("I2C read: I/O error\n");
 330                         i2c_init(CONFIG_SYS_I2C_SPEED, CONFIG_SYS_I2C_SLAVE);
 331                         return 1;
 332                 }
 333         }
 334
 335         return 0;
 336 }
 337
 338 int i2c_write(uchar chip, uint addr, int alen, uchar *buffer, int len)
 339 {
 340         int i;
 341         u16 status;
 342         int i2c_error = 0;
 343         u16 w;
 344         u8 tmpbuf[2] = {addr >> 8, addr & 0xff};
 345
 346         if (alen > 2) {
 347                 printf("I2C write: addr len %d not supported\n", alen);
 348                 return 1;
 349         }
 350
 351         if (addr + len > (1 << 16)) {
 352                 printf("I2C write: address 0x%x + 0x%x out of range\n",
 353                                 addr, len);
 354                 return 1;
 355         }
 356
 357         /* wait until bus not busy */
 358         wait_for_bb();
 359
 360         /* start address phase - will write regoffset + len bytes data */
 361         /* TODO consider case when !CONFIG_OMAP243X/34XX/44XX */
 362         writew(alen + len, &i2c_base->cnt);
 363         /* set slave address */
 364         writew(chip, &i2c_base->sa);
 365         /* stop bit needed here */
 366         writew(I2C_CON_EN | I2C_CON_MST | I2C_CON_STT | I2C_CON_TRX |
 367                 I2C_CON_STP, &i2c_base->con);
 368
 369         /* Send address and data */
 370         for (i = -alen; i < len; i++) {
 371                 status = wait_for_pin();
 372
 373                 if (status == 0 || status & I2C_STAT_NACK) {
 374                         i2c_error = 1;
 375                         printf("i2c error waiting for data ACK (status=0x%x)\n",
 376                                         status);
 377                         goto write_exit;
 378                 }
 379
 380                 if (status & I2C_STAT_XRDY) {
 381                         w = (i < 0) ? tmpbuf[2+i] : buffer[i];
 382 #if !(defined(CONFIG_OMAP243X) || defined(CONFIG_OMAP34XX) || \
 383         defined(CONFIG_OMAP44XX) || defined(CONFIG_AM33XX) || \
 384         defined(CONFIG_OMAP54XX))
 385                         w |= ((++i < 0) ? tmpbuf[2+i] : buffer[i]) << 8;
 386 #endif
 387                         writew(w, &i2c_base->data);
 388                         writew(I2C_STAT_XRDY, &i2c_base->stat);
 389                 } else {
 390                         i2c_error = 1;
 391                         printf("i2c bus not ready for Tx (i=%d)\n", i);
 392                         goto write_exit;
 393                 }
 394         }
 395
 396 write_exit:
 397         flush_fifo();
 398         writew(0xFFFF, &i2c_base->stat);
 399         return i2c_error;
 400 }
 401
 402 static void wait_for_bb(void)
 403 {
 404         int timeout = I2C_TIMEOUT;
 405         u16 stat;
 406
 407         writew(0xFFFF, &i2c_base->stat);        /* clear current interrupts...*/
 408         while ((stat = readw(&i2c_base->stat) & I2C_STAT_BB) && timeout--) {
 409                 writew(stat, &i2c_base->stat);
 410                 udelay(1000);
 411         }
 412
 413         if (timeout <= 0) {
 414                 printf("timed out in wait_for_bb: I2C_STAT=%x\n",
 415                         readw(&i2c_base->stat));
 416         }
 417         writew(0xFFFF, &i2c_base->stat);         /* clear delayed stuff*/
 418 }
 419
 420 static u16 wait_for_pin(void)
 421 {
 422         u16 status;
 423         int timeout = I2C_TIMEOUT;
 424
 425         do {
 426                 udelay(1000);
 427                 status = readw(&i2c_base->stat);
 428         } while (!(status &
 429                    (I2C_STAT_ROVR | I2C_STAT_XUDF | I2C_STAT_XRDY |
 430                     I2C_STAT_RRDY | I2C_STAT_ARDY | I2C_STAT_NACK |
 431                     I2C_STAT_AL)) && timeout--);
 432
 433         if (timeout <= 0) {
 434                 printf("timed out in wait_for_pin: I2C_STAT=%x\n",
 435                         readw(&i2c_base->stat));
 436                 writew(0xFFFF, &i2c_base->stat);
 437                 status = 0;
 438         }
 439
 440         return status;
 441 }
 442
 443 int i2c_set_bus_num(unsigned int bus)
 444 {
 445         if ((bus < 0) || (bus >= I2C_BUS_MAX)) {
 446                 printf("Bad bus: %d\n", bus);
 447                 return -1;
 448         }
 449
 450 #if I2C_BUS_MAX == 4
 451         if (bus == 3)
 452                 i2c_base = (struct i2c *)I2C_BASE4;
 453         else
 454         if (bus == 2)
 455                 i2c_base = (struct i2c *)I2C_BASE3;
 456         else
 457 #endif
 458 #if I2C_BUS_MAX == 3
 459         if (bus == 2)
 460                 i2c_base = (struct i2c *)I2C_BASE3;
 461         else
 462 #endif
 463         if (bus == 1)
 464                 i2c_base = (struct i2c *)I2C_BASE2;
 465         else
 466                 i2c_base = (struct i2c *)I2C_BASE1;
 467
 468         current_bus = bus;
 469
 470         if (!bus_initialized[current_bus])
 471                 i2c_init(CONFIG_SYS_I2C_SPEED, CONFIG_SYS_I2C_SLAVE);
 472
 473         return 0;
 474 }
 475
 476 int i2c_get_bus_num(void)
 477 {
 478         return (int) current_bus;
 479 }