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 static struct i2c *i2c_base = (struct i2c *)I2C_DEFAULT_BASE;
  39
  40 static unsigned int bus_initialized[I2C_BUS_MAX];
  41 static unsigned int current_bus;
  42
  43 void i2c_init (int speed, int slaveadd)
  44 {
  45         int psc, fsscll, fssclh;
  46         int hsscll = 0, hssclh = 0;
  47         u32 scll, sclh;
  48         int timeout = I2C_TIMEOUT;
  49
  50         /* Only handle standard, fast and high speeds */
  51         if ((speed != OMAP_I2C_STANDARD) &&
  52             (speed != OMAP_I2C_FAST_MODE) &&
  53             (speed != OMAP_I2C_HIGH_SPEED)) {
  54                 printf("Error : I2C unsupported speed %d\n", speed);
  55                 return;
  56         }
  57
  58         psc = I2C_IP_CLK / I2C_INTERNAL_SAMPLING_CLK;
  59         psc -= 1;
  60         if (psc < I2C_PSC_MIN) {
  61                 printf("Error : I2C unsupported prescalar %d\n", psc);
  62                 return;
  63         }
  64
  65         if (speed == OMAP_I2C_HIGH_SPEED) {
  66                 /* High speed */
  67
  68                 /* For first phase of HS mode */
  69                 fsscll = fssclh = I2C_INTERNAL_SAMPLING_CLK /
  70                         (2 * OMAP_I2C_FAST_MODE);
  71
  72                 fsscll -= I2C_HIGHSPEED_PHASE_ONE_SCLL_TRIM;
  73                 fssclh -= I2C_HIGHSPEED_PHASE_ONE_SCLH_TRIM;
  74                 if (((fsscll < 0) || (fssclh < 0)) ||
  75                     ((fsscll > 255) || (fssclh > 255))) {
  76                         printf("Error : I2C initializing first phase clock\n");
  77                         return;
  78                 }
  79
  80                 /* For second phase of HS mode */
  81                 hsscll = hssclh = I2C_INTERNAL_SAMPLING_CLK / (2 * speed);
  82
  83                 hsscll -= I2C_HIGHSPEED_PHASE_TWO_SCLL_TRIM;
  84                 hssclh -= I2C_HIGHSPEED_PHASE_TWO_SCLH_TRIM;
  85                 if (((fsscll < 0) || (fssclh < 0)) ||
  86                     ((fsscll > 255) || (fssclh > 255))) {
  87                         printf("Error : I2C initializing second phase clock\n");
  88                         return;
  89                 }
  90
  91                 scll = (unsigned int)hsscll << 8 | (unsigned int)fsscll;
  92                 sclh = (unsigned int)hssclh << 8 | (unsigned int)fssclh;
  93
  94         } else {
  95                 /* Standard and fast speed */
  96                 fsscll = fssclh = I2C_INTERNAL_SAMPLING_CLK / (2 * speed);
  97
  98                 fsscll -= I2C_FASTSPEED_SCLL_TRIM;
  99                 fssclh -= I2C_FASTSPEED_SCLH_TRIM;
 100                 if (((fsscll < 0) || (fssclh < 0)) ||
 101                     ((fsscll > 255) || (fssclh > 255))) {
 102                         printf("Error : I2C initializing clock\n");
 103                         return;
 104                 }
 105
 106                 scll = (unsigned int)fsscll;
 107                 sclh = (unsigned int)fssclh;
 108         }
 109
 110         if (readw (&i2c_base->con) & I2C_CON_EN) {
 111                 writew (0, &i2c_base->con);
 112                 udelay (50000);
 113         }
 114
 115         writew(0x2, &i2c_base->sysc); /* for ES2 after soft reset */
 116         udelay(1000);
 117
 118         writew(I2C_CON_EN, &i2c_base->con);
 119         while (!(readw(&i2c_base->syss) & I2C_SYSS_RDONE) && timeout--) {
 120                 if (timeout <= 0) {
 121                         printf("ERROR: Timeout in soft-reset\n");
 122                         return;
 123                 }
 124                 udelay(1000);
 125         }
 126
 127         writew(0, &i2c_base->con);
 128         writew(psc, &i2c_base->psc);
 129         writew(scll, &i2c_base->scll);
 130         writew(sclh, &i2c_base->sclh);
 131
 132         /* own address */
 133         writew (slaveadd, &i2c_base->oa);
 134         writew (I2C_CON_EN, &i2c_base->con);
 135
 136         /* have to enable intrrupts or OMAP i2c module doesn't work */
 137         writew (I2C_IE_XRDY_IE | I2C_IE_RRDY_IE | I2C_IE_ARDY_IE |
 138                 I2C_IE_NACK_IE | I2C_IE_AL_IE, &i2c_base->ie);
 139         udelay (1000);
 140         flush_fifo();
 141         writew (0xFFFF, &i2c_base->stat);
 142         writew (0, &i2c_base->cnt);
 143
 144         if (gd->flags & GD_FLG_RELOC)
 145                 bus_initialized[current_bus] = 1;
 146 }
 147
 148 static int i2c_read_byte (u8 devaddr, u8 regoffset, u8 * value)
 149 {
 150         int i2c_error = 0;
 151         u16 status;
 152
 153         /* wait until bus not busy */
 154         wait_for_bb ();
 155
 156         /* one byte only */
 157         writew (1, &i2c_base->cnt);
 158         /* set slave address */
 159         writew (devaddr, &i2c_base->sa);
 160         /* no stop bit needed here */
 161         writew (I2C_CON_EN | I2C_CON_MST | I2C_CON_STT | I2C_CON_TRX, &i2c_base->con);
 162
 163         /* send register offset */
 164         while (1) {
 165                 status = wait_for_pin();
 166                 if (status == 0 || status & I2C_STAT_NACK) {
 167                         i2c_error = 1;
 168                         goto read_exit;
 169                 }
 170                 if (status & I2C_STAT_XRDY) {
 171                         /* Important: have to use byte access */
 172                         writeb(regoffset, &i2c_base->data);
 173                         writew(I2C_STAT_XRDY, &i2c_base->stat);
 174                 }
 175                 if (status & I2C_STAT_ARDY) {
 176                         writew(I2C_STAT_ARDY, &i2c_base->stat);
 177                         break;
 178                 }
 179         }
 180
 181         /* set slave address */
 182         writew(devaddr, &i2c_base->sa);
 183         /* read one byte from slave */
 184         writew(1, &i2c_base->cnt);
 185         /* need stop bit here */
 186         writew(I2C_CON_EN | I2C_CON_MST |
 187                 I2C_CON_STT | I2C_CON_STP,
 188                 &i2c_base->con);
 189
 190         /* receive data */
 191         while (1) {
 192                 status = wait_for_pin();
 193                 if (status == 0 || status & I2C_STAT_NACK) {
 194                         i2c_error = 1;
 195                         goto read_exit;
 196                 }
 197                 if (status & I2C_STAT_RRDY) {
 198 #if defined(CONFIG_OMAP243X) || defined(CONFIG_OMAP34XX) || \
 199     defined(CONFIG_OMAP44XX)
 200                         *value = readb(&i2c_base->data);
 201 #else
 202                         *value = readw(&i2c_base->data);
 203 #endif
 204                         writew(I2C_STAT_RRDY, &i2c_base->stat);
 205                 }
 206                 if (status & I2C_STAT_ARDY) {
 207                         writew(I2C_STAT_ARDY, &i2c_base->stat);
 208                         break;
 209                 }
 210         }
 211
 212 read_exit:
 213         flush_fifo();
 214         writew (0xFFFF, &i2c_base->stat);
 215         writew (0, &i2c_base->cnt);
 216         return i2c_error;
 217 }
 218
 219 static int i2c_write_byte (u8 devaddr, u8 regoffset, u8 value)
 220 {
 221         int i2c_error = 0;
 222         u16 status;
 223
 224         /* wait until bus not busy */
 225         wait_for_bb ();
 226
 227         /* two bytes */
 228         writew (2, &i2c_base->cnt);
 229         /* set slave address */
 230         writew (devaddr, &i2c_base->sa);
 231         /* stop bit needed here */
 232         writew (I2C_CON_EN | I2C_CON_MST | I2C_CON_STT | I2C_CON_TRX |
 233                 I2C_CON_STP, &i2c_base->con);
 234
 235         while (1) {
 236                 status = wait_for_pin();
 237                 if (status == 0 || status & I2C_STAT_NACK) {
 238                         i2c_error = 1;
 239                         goto write_exit;
 240                 }
 241                 if (status & I2C_STAT_XRDY) {
 242 #if defined(CONFIG_OMAP243X) || defined(CONFIG_OMAP34XX) || \
 243     defined(CONFIG_OMAP44XX)
 244                         /* send register offset */
 245                         writeb(regoffset, &i2c_base->data);
 246                         writew(I2C_STAT_XRDY, &i2c_base->stat);
 247
 248                         while (1) {
 249                                 status = wait_for_pin();
 250                                 if (status == 0 || status & I2C_STAT_NACK) {
 251                                         i2c_error = 1;
 252                                         goto write_exit;
 253                                 }
 254                                 if (status & I2C_STAT_XRDY) {
 255                                         /* send data */
 256                                         writeb(value, &i2c_base->data);
 257                                         writew(I2C_STAT_XRDY, &i2c_base->stat);
 258                                 }
 259                                 if (status & I2C_STAT_ARDY) {
 260                                         writew(I2C_STAT_ARDY, &i2c_base->stat);
 261                                         break;
 262                                 }
 263                         }
 264                         break;
 265 #else
 266                         /* send out two bytes */
 267                         writew((value << 8) + regoffset, &i2c_base->data);
 268                         writew(I2C_STAT_XRDY, &i2c_base->stat);
 269 #endif
 270                 }
 271                 if (status & I2C_STAT_ARDY) {
 272                         writew(I2C_STAT_ARDY, &i2c_base->stat);
 273                         break;
 274                 }
 275         }
 276
 277         wait_for_bb();
 278
 279         status = readw(&i2c_base->stat);
 280         if (status & I2C_STAT_NACK)
 281                 i2c_error = 1;
 282
 283 write_exit:
 284         flush_fifo();
 285         writew (0xFFFF, &i2c_base->stat);
 286         writew (0, &i2c_base->cnt);
 287         return i2c_error;
 288 }
 289
 290 static void flush_fifo(void)
 291 {       u16 stat;
 292
 293         /* note: if you try and read data when its not there or ready
 294          * you get a bus error
 295          */
 296         while(1){
 297                 stat = readw(&i2c_base->stat);
 298                 if(stat == I2C_STAT_RRDY){
 299 #if defined(CONFIG_OMAP243X) || defined(CONFIG_OMAP34XX) || \
 300     defined(CONFIG_OMAP44XX)
 301                         readb(&i2c_base->data);
 302 #else
 303                         readw(&i2c_base->data);
 304 #endif
 305                         writew(I2C_STAT_RRDY,&i2c_base->stat);
 306                         udelay(1000);
 307                 }else
 308                         break;
 309         }
 310 }
 311
 312 int i2c_probe (uchar chip)
 313 {
 314         u16 status;
 315         int res = 1; /* default = fail */
 316
 317         if (chip == readw (&i2c_base->oa)) {
 318                 return res;
 319         }
 320
 321         /* wait until bus not busy */
 322         wait_for_bb ();
 323
 324         /* try to write one byte */
 325         writew (1, &i2c_base->cnt);
 326         /* set slave address */
 327         writew (chip, &i2c_base->sa);
 328         /* stop bit needed here */
 329         writew(I2C_CON_EN | I2C_CON_MST | I2C_CON_STT | I2C_CON_TRX |
 330                I2C_CON_STP, &i2c_base->con);
 331
 332         status = wait_for_pin();
 333
 334         /* check for ACK (!NAK) */
 335         if (!(status & I2C_STAT_NACK))
 336                 res = 0;
 337
 338         /* abort transfer (force idle state) */
 339         writew(0, &i2c_base->con);
 340
 341         flush_fifo();
 342         writew (0, &i2c_base->cnt); /* don't allow any more data in...we don't want it.*/
 343         writew(0xFFFF, &i2c_base->stat);
 344         return res;
 345 }
 346
 347 int i2c_read (uchar chip, uint addr, int alen, uchar * buffer, int len)
 348 {
 349         int i;
 350
 351         if (alen > 1) {
 352                 printf ("I2C read: addr len %d not supported\n", alen);
 353                 return 1;
 354         }
 355
 356         if (addr + len > 256) {
 357                 printf ("I2C read: address out of range\n");
 358                 return 1;
 359         }
 360
 361         for (i = 0; i < len; i++) {
 362                 if (i2c_read_byte (chip, addr + i, &buffer[i])) {
 363                         printf ("I2C read: I/O error\n");
 364                         i2c_init (CONFIG_SYS_I2C_SPEED, CONFIG_SYS_I2C_SLAVE);
 365                         return 1;
 366                 }
 367         }
 368
 369         return 0;
 370 }
 371
 372 int i2c_write (uchar chip, uint addr, int alen, uchar * buffer, int len)
 373 {
 374         int i;
 375
 376         if (alen > 1) {
 377                 printf ("I2C read: addr len %d not supported\n", alen);
 378                 return 1;
 379         }
 380
 381         if (addr + len > 256) {
 382                 printf ("I2C read: address out of range\n");
 383                 return 1;
 384         }
 385
 386         for (i = 0; i < len; i++) {
 387                 if (i2c_write_byte (chip, addr + i, buffer[i])) {
 388                         printf ("I2C read: I/O error\n");
 389                         i2c_init (CONFIG_SYS_I2C_SPEED, CONFIG_SYS_I2C_SLAVE);
 390                         return 1;
 391                 }
 392         }
 393
 394         return 0;
 395 }
 396
 397 static void wait_for_bb (void)
 398 {
 399         int timeout = I2C_TIMEOUT;
 400         u16 stat;
 401
 402         writew(0xFFFF, &i2c_base->stat);         /* clear current interruts...*/
 403         while ((stat = readw (&i2c_base->stat) & I2C_STAT_BB) && timeout--) {
 404                 writew (stat, &i2c_base->stat);
 405                 udelay(1000);
 406         }
 407
 408         if (timeout <= 0) {
 409                 printf ("timed out in wait_for_bb: I2C_STAT=%x\n",
 410                         readw (&i2c_base->stat));
 411         }
 412         writew(0xFFFF, &i2c_base->stat);         /* clear delayed stuff*/
 413 }
 414
 415 static u16 wait_for_pin (void)
 416 {
 417         u16 status;
 418         int timeout = I2C_TIMEOUT;
 419
 420         do {
 421                 udelay (1000);
 422                 status = readw (&i2c_base->stat);
 423         } while (  !(status &
 424                    (I2C_STAT_ROVR | I2C_STAT_XUDF | I2C_STAT_XRDY |
 425                     I2C_STAT_RRDY | I2C_STAT_ARDY | I2C_STAT_NACK |
 426                     I2C_STAT_AL)) && timeout--);
 427
 428         if (timeout <= 0) {
 429                 printf ("timed out in wait_for_pin: I2C_STAT=%x\n",
 430                         readw (&i2c_base->stat));
 431                 writew(0xFFFF, &i2c_base->stat);
 432                 status = 0;
 433         }
 434
 435         return status;
 436 }
 437
 438 int i2c_set_bus_num(unsigned int bus)
 439 {
 440         if ((bus < 0) || (bus >= I2C_BUS_MAX)) {
 441                 printf("Bad bus: %d\n", bus);
 442                 return -1;
 443         }
 444
 445 #if I2C_BUS_MAX==3
 446         if (bus == 2)
 447                 i2c_base = (struct i2c *)I2C_BASE3;
 448         else
 449 #endif
 450         if (bus == 1)
 451                 i2c_base = (struct i2c *)I2C_BASE2;
 452         else
 453                 i2c_base = (struct i2c *)I2C_BASE1;
 454
 455         current_bus = bus;
 456
 457         if(!bus_initialized[current_bus])
 458                 i2c_init(CONFIG_SYS_I2C_SPEED, CONFIG_SYS_I2C_SLAVE);
 459
 460         return 0;
 461 }
 462
 463 int i2c_get_bus_num(void)
 464 {
 465         return (int) current_bus;
 466 }