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 #define I2C_TIMEOUT     1000
  31
  32 static void wait_for_bb (void);
  33 static u16 wait_for_pin (void);
  34 static void flush_fifo(void);
  35
  36 static struct i2c *i2c_base = (struct i2c *)I2C_DEFAULT_BASE;
  37
  38 static unsigned int bus_initialized[I2C_BUS_MAX];
  39 static unsigned int current_bus;
  40
  41 void i2c_init (int speed, int slaveadd)
  42 {
  43         DECLARE_GLOBAL_DATA_PTR;
  44         int psc, fsscll, fssclh;
  45         int hsscll = 0, hssclh = 0;
  46         u32 scll, sclh;
  47         int timeout = I2C_TIMEOUT;
  48
  49         /* Only handle standard, fast and high speeds */
  50         if ((speed != OMAP_I2C_STANDARD) &&
  51             (speed != OMAP_I2C_FAST_MODE) &&
  52             (speed != OMAP_I2C_HIGH_SPEED)) {
  53                 printf("Error : I2C unsupported speed %d\n", speed);
  54                 return;
  55         }
  56
  57         psc = I2C_IP_CLK / I2C_INTERNAL_SAMPLING_CLK;
  58         psc -= 1;
  59         if (psc < I2C_PSC_MIN) {
  60                 printf("Error : I2C unsupported prescalar %d\n", psc);
  61                 return;
  62         }
  63
  64         if (speed == OMAP_I2C_HIGH_SPEED) {
  65                 /* High speed */
  66
  67                 /* For first phase of HS mode */
  68                 fsscll = fssclh = I2C_INTERNAL_SAMPLING_CLK /
  69                         (2 * OMAP_I2C_FAST_MODE);
  70
  71                 fsscll -= I2C_HIGHSPEED_PHASE_ONE_SCLL_TRIM;
  72                 fssclh -= I2C_HIGHSPEED_PHASE_ONE_SCLH_TRIM;
  73                 if (((fsscll < 0) || (fssclh < 0)) ||
  74                     ((fsscll > 255) || (fssclh > 255))) {
  75                         printf("Error : I2C initializing first phase clock\n");
  76                         return;
  77                 }
  78
  79                 /* For second phase of HS mode */
  80                 hsscll = hssclh = I2C_INTERNAL_SAMPLING_CLK / (2 * speed);
  81
  82                 hsscll -= I2C_HIGHSPEED_PHASE_TWO_SCLL_TRIM;
  83                 hssclh -= I2C_HIGHSPEED_PHASE_TWO_SCLH_TRIM;
  84                 if (((fsscll < 0) || (fssclh < 0)) ||
  85                     ((fsscll > 255) || (fssclh > 255))) {
  86                         printf("Error : I2C initializing second phase clock\n");
  87                         return;
  88                 }
  89
  90                 scll = (unsigned int)hsscll << 8 | (unsigned int)fsscll;
  91                 sclh = (unsigned int)hssclh << 8 | (unsigned int)fssclh;
  92
  93         } else {
  94                 /* Standard and fast speed */
  95                 fsscll = fssclh = I2C_INTERNAL_SAMPLING_CLK / (2 * speed);
  96
  97                 fsscll -= I2C_FASTSPEED_SCLL_TRIM;
  98                 fssclh -= I2C_FASTSPEED_SCLH_TRIM;
  99                 if (((fsscll < 0) || (fssclh < 0)) ||
 100                     ((fsscll > 255) || (fssclh > 255))) {
 101                         printf("Error : I2C initializing clock\n");
 102                         return;
 103                 }
 104
 105                 scll = (unsigned int)fsscll;
 106                 sclh = (unsigned int)fssclh;
 107         }
 108
 109         if (readw (&i2c_base->con) & I2C_CON_EN) {
 110                 writew (0, &i2c_base->con);
 111                 udelay (50000);
 112         }
 113
 114         writew(0x2, &i2c_base->sysc); /* for ES2 after soft reset */
 115         udelay(1000);
 116
 117         writew(I2C_CON_EN, &i2c_base->con);
 118         while (!(readw(&i2c_base->syss) & I2C_SYSS_RDONE) && timeout--) {
 119                 if (timeout <= 0) {
 120                         printf("ERROR: Timeout in soft-reset\n");
 121                         return;
 122                 }
 123                 udelay(1000);
 124         }
 125
 126         writew(0, &i2c_base->con);
 127         writew(psc, &i2c_base->psc);
 128         writew(scll, &i2c_base->scll);
 129         writew(sclh, &i2c_base->sclh);
 130
 131         /* own address */
 132         writew (slaveadd, &i2c_base->oa);
 133         writew (I2C_CON_EN, &i2c_base->con);
 134
 135         /* have to enable intrrupts or OMAP i2c module doesn't work */
 136         writew (I2C_IE_XRDY_IE | I2C_IE_RRDY_IE | I2C_IE_ARDY_IE |
 137                 I2C_IE_NACK_IE | I2C_IE_AL_IE, &i2c_base->ie);
 138         udelay (1000);
 139         flush_fifo();
 140         writew (0xFFFF, &i2c_base->stat);
 141         writew (0, &i2c_base->cnt);
 142
 143         if (gd->flags & GD_FLG_RELOC)
 144                 bus_initialized[current_bus] = 1;
 145 }
 146
 147 static int i2c_read_byte (u8 devaddr, u8 regoffset, u8 * value)
 148 {
 149         int i2c_error = 0;
 150         u16 status;
 151
 152         /* wait until bus not busy */
 153         wait_for_bb ();
 154
 155         /* one byte only */
 156         writew (1, &i2c_base->cnt);
 157         /* set slave address */
 158         writew (devaddr, &i2c_base->sa);
 159         /* no stop bit needed here */
 160         writew (I2C_CON_EN | I2C_CON_MST | I2C_CON_STT | I2C_CON_TRX, &i2c_base->con);
 161
 162         /* send register offset */
 163         while (1) {
 164                 status = wait_for_pin();
 165                 if (status == 0 || status & I2C_STAT_NACK) {
 166                         i2c_error = 1;
 167                         goto read_exit;
 168                 }
 169                 if (status & I2C_STAT_XRDY) {
 170                         /* Important: have to use byte access */
 171                         writeb(regoffset, &i2c_base->data);
 172                         writew(I2C_STAT_XRDY, &i2c_base->stat);
 173                 }
 174                 if (status & I2C_STAT_ARDY) {
 175                         writew(I2C_STAT_ARDY, &i2c_base->stat);
 176                         break;
 177                 }
 178         }
 179
 180         /* set slave address */
 181         writew(devaddr, &i2c_base->sa);
 182         /* read one byte from slave */
 183         writew(1, &i2c_base->cnt);
 184         /* need stop bit here */
 185         writew(I2C_CON_EN | I2C_CON_MST |
 186                 I2C_CON_STT | I2C_CON_STP,
 187                 &i2c_base->con);
 188
 189         /* receive data */
 190         while (1) {
 191                 status = wait_for_pin();
 192                 if (status == 0 || status & I2C_STAT_NACK) {
 193                         i2c_error = 1;
 194                         goto read_exit;
 195                 }
 196                 if (status & I2C_STAT_RRDY) {
 197 #if defined(CONFIG_OMAP243X) || defined(CONFIG_OMAP34XX) || \
 198     defined(CONFIG_OMAP44XX)
 199                         *value = readb(&i2c_base->data);
 200 #else
 201                         *value = readw(&i2c_base->data);
 202 #endif
 203                         writew(I2C_STAT_RRDY, &i2c_base->stat);
 204                 }
 205                 if (status & I2C_STAT_ARDY) {
 206                         writew(I2C_STAT_ARDY, &i2c_base->stat);
 207                         break;
 208                 }
 209         }
 210
 211 read_exit:
 212         flush_fifo();
 213         writew (0xFFFF, &i2c_base->stat);
 214         writew (0, &i2c_base->cnt);
 215         return i2c_error;
 216 }
 217
 218 static int i2c_write_byte (u8 devaddr, u8 regoffset, u8 value)
 219 {
 220         int i2c_error = 0;
 221         u16 status, stat;
 222
 223         /* wait until bus not busy */
 224         wait_for_bb ();
 225
 226         /* two bytes */
 227         writew (2, &i2c_base->cnt);
 228         /* set slave address */
 229         writew (devaddr, &i2c_base->sa);
 230         /* stop bit needed here */
 231         writew (I2C_CON_EN | I2C_CON_MST | I2C_CON_STT | I2C_CON_TRX |
 232                 I2C_CON_STP, &i2c_base->con);
 233
 234         /* wait until state change */
 235         status = wait_for_pin ();
 236
 237         if (status & I2C_STAT_XRDY) {
 238 #if defined(CONFIG_OMAP243X) || defined(CONFIG_OMAP34XX) || \
 239     defined(CONFIG_OMAP44XX)
 240                 /* send out 1 byte */
 241                 writeb (regoffset, &i2c_base->data);
 242                 writew (I2C_STAT_XRDY, &i2c_base->stat);
 243
 244                 status = wait_for_pin ();
 245                 if ((status & I2C_STAT_XRDY)) {
 246                         /* send out next 1 byte */
 247                         writeb (value, &i2c_base->data);
 248                         writew (I2C_STAT_XRDY, &i2c_base->stat);
 249                 } else {
 250                         i2c_error = 1;
 251                 }
 252 #else
 253                 /* send out two bytes */
 254                 writew ((value << 8) + regoffset, &i2c_base->data);
 255 #endif
 256                 /* must have enough delay to allow BB bit to go low */
 257                 udelay (50000);
 258                 if (readw (&i2c_base->stat) & I2C_STAT_NACK) {
 259                         i2c_error = 1;
 260                 }
 261         } else {
 262                 i2c_error = 1;
 263         }
 264
 265         if (!i2c_error) {
 266                 int eout = 200;
 267
 268                 writew (I2C_CON_EN, &i2c_base->con);
 269                 while ((stat = readw (&i2c_base->stat)) || (readw (&i2c_base->con) & I2C_CON_MST)) {
 270                         udelay (1000);
 271                         /* have to read to clear intrrupt */
 272                         writew (0xFFFF, &i2c_base->stat);
 273                         if(--eout == 0) /* better leave with error than hang */
 274                                 break;
 275                 }
 276         }
 277         flush_fifo();
 278         writew (0xFFFF, &i2c_base->stat);
 279         writew (0, &i2c_base->cnt);
 280         return i2c_error;
 281 }
 282
 283 static void flush_fifo(void)
 284 {       u16 stat;
 285
 286         /* note: if you try and read data when its not there or ready
 287          * you get a bus error
 288          */
 289         while(1){
 290                 stat = readw(&i2c_base->stat);
 291                 if(stat == I2C_STAT_RRDY){
 292 #if defined(CONFIG_OMAP243X) || defined(CONFIG_OMAP34XX) || \
 293     defined(CONFIG_OMAP44XX)
 294                         readb(&i2c_base->data);
 295 #else
 296                         readw(&i2c_base->data);
 297 #endif
 298                         writew(I2C_STAT_RRDY,&i2c_base->stat);
 299                         udelay(1000);
 300                 }else
 301                         break;
 302         }
 303 }
 304
 305 int i2c_probe (uchar chip)
 306 {
 307         int res = 1; /* default = fail */
 308
 309         if (chip == readw (&i2c_base->oa)) {
 310                 return res;
 311         }
 312
 313         /* wait until bus not busy */
 314         wait_for_bb ();
 315
 316         /* try to read one byte */
 317         writew (1, &i2c_base->cnt);
 318         /* set slave address */
 319         writew (chip, &i2c_base->sa);
 320         /* stop bit needed here */
 321         writew (I2C_CON_EN | I2C_CON_MST | I2C_CON_STT | I2C_CON_STP, &i2c_base->con);
 322         /* enough delay for the NACK bit set */
 323         udelay (50000);
 324
 325         if (!(readw (&i2c_base->stat) & I2C_STAT_NACK)) {
 326                 res = 0;      /* success case */
 327                 flush_fifo();
 328                 writew(0xFFFF, &i2c_base->stat);
 329         } else {
 330                 writew(0xFFFF, &i2c_base->stat);         /* failue, clear sources*/
 331                 writew (readw (&i2c_base->con) | I2C_CON_STP, &i2c_base->con); /* finish up xfer */
 332                 udelay(20000);
 333                 wait_for_bb ();
 334         }
 335         flush_fifo();
 336         writew (0, &i2c_base->cnt); /* don't allow any more data in...we don't want it.*/
 337         writew(0xFFFF, &i2c_base->stat);
 338         return res;
 339 }
 340
 341 int i2c_read (uchar chip, uint addr, int alen, uchar * buffer, int len)
 342 {
 343         int i;
 344
 345         if (alen > 1) {
 346                 printf ("I2C read: addr len %d not supported\n", alen);
 347                 return 1;
 348         }
 349
 350         if (addr + len > 256) {
 351                 printf ("I2C read: address out of range\n");
 352                 return 1;
 353         }
 354
 355         for (i = 0; i < len; i++) {
 356                 if (i2c_read_byte (chip, addr + i, &buffer[i])) {
 357                         printf ("I2C read: I/O error\n");
 358                         i2c_init (CONFIG_SYS_I2C_SPEED, CONFIG_SYS_I2C_SLAVE);
 359                         return 1;
 360                 }
 361         }
 362
 363         return 0;
 364 }
 365
 366 int i2c_write (uchar chip, uint addr, int alen, uchar * buffer, int len)
 367 {
 368         int i;
 369
 370         if (alen > 1) {
 371                 printf ("I2C read: addr len %d not supported\n", alen);
 372                 return 1;
 373         }
 374
 375         if (addr + len > 256) {
 376                 printf ("I2C read: address out of range\n");
 377                 return 1;
 378         }
 379
 380         for (i = 0; i < len; i++) {
 381                 if (i2c_write_byte (chip, addr + i, buffer[i])) {
 382                         printf ("I2C read: I/O error\n");
 383                         i2c_init (CONFIG_SYS_I2C_SPEED, CONFIG_SYS_I2C_SLAVE);
 384                         return 1;
 385                 }
 386         }
 387
 388         return 0;
 389 }
 390
 391 static void wait_for_bb (void)
 392 {
 393         int timeout = I2C_TIMEOUT;
 394         u16 stat;
 395
 396         writew(0xFFFF, &i2c_base->stat);         /* clear current interruts...*/
 397         while ((stat = readw (&i2c_base->stat) & I2C_STAT_BB) && timeout--) {
 398                 writew (stat, &i2c_base->stat);
 399                 udelay(1000);
 400         }
 401
 402         if (timeout <= 0) {
 403                 printf ("timed out in wait_for_bb: I2C_STAT=%x\n",
 404                         readw (&i2c_base->stat));
 405         }
 406         writew(0xFFFF, &i2c_base->stat);         /* clear delayed stuff*/
 407 }
 408
 409 static u16 wait_for_pin (void)
 410 {
 411         u16 status;
 412         int timeout = I2C_TIMEOUT;
 413
 414         do {
 415                 udelay (1000);
 416                 status = readw (&i2c_base->stat);
 417         } while (  !(status &
 418                    (I2C_STAT_ROVR | I2C_STAT_XUDF | I2C_STAT_XRDY |
 419                     I2C_STAT_RRDY | I2C_STAT_ARDY | I2C_STAT_NACK |
 420                     I2C_STAT_AL)) && timeout--);
 421
 422         if (timeout <= 0) {
 423                 printf ("timed out in wait_for_pin: I2C_STAT=%x\n",
 424                         readw (&i2c_base->stat));
 425                 writew(0xFFFF, &i2c_base->stat);
 426                 status = 0;
 427         }
 428
 429         return status;
 430 }
 431
 432 int i2c_set_bus_num(unsigned int bus)
 433 {
 434         if ((bus < 0) || (bus >= I2C_BUS_MAX)) {
 435                 printf("Bad bus: %d\n", bus);
 436                 return -1;
 437         }
 438
 439 #if I2C_BUS_MAX==3
 440         if (bus == 2)
 441                 i2c_base = (struct i2c *)I2C_BASE3;
 442         else
 443 #endif
 444         if (bus == 1)
 445                 i2c_base = (struct i2c *)I2C_BASE2;
 446         else
 447                 i2c_base = (struct i2c *)I2C_BASE1;
 448
 449         current_bus = bus;
 450
 451         if(!bus_initialized[current_bus])
 452                 i2c_init(CONFIG_SYS_I2C_SPEED, CONFIG_SYS_I2C_SLAVE);
 453
 454         return 0;
 455 }
 456
 457 int i2c_get_bus_num(void)
 458 {
 459         return (int) current_bus;
 460 }