cpu/arm920t/s3c24x0/i2c.c

   1 /*
   2  * (C) Copyright 2002
   3  * David Mueller, ELSOFT AG, d.mueller@elsoft.ch
   4  *
   5  * See file CREDITS for list of people who contributed to this
   6  * project.
   7  *
   8  * This program is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU General Public License as
  10  * published by the Free Software Foundation; either version 2 of
  11  * the License, or (at your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program; if not, write to the Free Software
  20  * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
  21  * MA 02111-1307 USA
  22  */
  23
  24 /* This code should work for both the S3C2400 and the S3C2410
  25  * as they seem to have the same I2C controller inside.
  26  * The different address mapping is handled by the s3c24xx.h files below.
  27  */
  28
  29 #include <common.h>
  30
  31 #ifdef CONFIG_DRIVER_S3C24X0_I2C
  32
  33 #if defined(CONFIG_S3C2400)
  34 #include <s3c2400.h>
  35 #elif defined(CONFIG_S3C2410)
  36 #include <s3c2410.h>
  37 #endif
  38 #include <i2c.h>
  39
  40 #ifdef CONFIG_HARD_I2C
  41
  42 #define I2C_WRITE       0
  43 #define I2C_READ        1
  44
  45 #define I2C_OK          0
  46 #define I2C_NOK         1
  47 #define I2C_NACK        2
  48 #define I2C_NOK_LA      3               /* Lost arbitration */
  49 #define I2C_NOK_TOUT    4               /* time out */
  50
  51 #define I2CSTAT_BSY     0x20            /* Busy bit */
  52 #define I2CSTAT_NACK    0x01            /* Nack bit */
  53 #define I2CCON_IRPND    0x10            /* Interrupt pending bit */
  54 #define I2C_MODE_MT     0xC0            /* Master Transmit Mode */
  55 #define I2C_MODE_MR     0x80            /* Master Receive Mode */
  56 #define I2C_START_STOP  0x20            /* START / STOP */
  57 #define I2C_TXRX_ENA    0x10            /* I2C Tx/Rx enable */
  58
  59 #define I2C_TIMEOUT 1                   /* 1 second */
  60
  61
  62 static int GetI2CSDA(void)
  63 {
  64         S3C24X0_GPIO * const gpio = S3C24X0_GetBase_GPIO();
  65
  66 #ifdef CONFIG_S3C2410
  67         return (gpio->GPEDAT & 0x8000) >> 15;
  68 #endif
  69 #ifdef CONFIG_S3C2400
  70         return (gpio->PGDAT & 0x0020) >> 5;
  71 #endif
  72 }
  73
  74 #if 0
  75 static void SetI2CSDA(int x)
  76 {
  77         rGPEDAT = (rGPEDAT & ~0x8000) | (x&1) << 15;
  78 }
  79 #endif
  80
  81 static void SetI2CSCL(int x)
  82 {
  83         S3C24X0_GPIO * const gpio = S3C24X0_GetBase_GPIO();
  84
  85 #ifdef CONFIG_S3C2410
  86         gpio->GPEDAT = (gpio->GPEDAT & ~0x4000) | (x&1) << 14;
  87 #endif
  88 #ifdef CONFIG_S3C2400
  89         gpio->PGDAT = (gpio->PGDAT & ~0x0040) | (x&1) << 6;
  90 #endif
  91 }
  92
  93
  94 static int WaitForXfer (void)
  95 {
  96         S3C24X0_I2C *const i2c = S3C24X0_GetBase_I2C ();
  97         int i, status;
  98
  99         i = I2C_TIMEOUT * 10000;
 100         status = i2c->IICCON;
 101         while ((i > 0) && !(status & I2CCON_IRPND)) {
 102                 udelay (100);
 103                 status = i2c->IICCON;
 104                 i--;
 105         }
 106
 107         return (status & I2CCON_IRPND) ? I2C_OK : I2C_NOK_TOUT;
 108 }
 109
 110 static int IsACK (void)
 111 {
 112         S3C24X0_I2C *const i2c = S3C24X0_GetBase_I2C ();
 113
 114         return (!(i2c->IICSTAT & I2CSTAT_NACK));
 115 }
 116
 117 static void ReadWriteByte (void)
 118 {
 119         S3C24X0_I2C *const i2c = S3C24X0_GetBase_I2C ();
 120
 121         i2c->IICCON &= ~I2CCON_IRPND;
 122 }
 123
 124 void i2c_init (int speed, int slaveadd)
 125 {
 126         S3C24X0_I2C *const i2c = S3C24X0_GetBase_I2C ();
 127         S3C24X0_GPIO *const gpio = S3C24X0_GetBase_GPIO ();
 128         ulong freq, pres = 16, div;
 129         int i, status;
 130
 131         /* wait for some time to give previous transfer a chance to finish */
 132
 133         i = I2C_TIMEOUT * 1000;
 134         status = i2c->IICSTAT;
 135         while ((i > 0) && (status & I2CSTAT_BSY)) {
 136                 udelay (1000);
 137                 status = i2c->IICSTAT;
 138                 i--;
 139         }
 140
 141         if ((status & I2CSTAT_BSY) || GetI2CSDA () == 0) {
 142 #ifdef CONFIG_S3C2410
 143                 ulong old_gpecon = gpio->GPECON;
 144 #endif
 145 #ifdef CONFIG_S3C2400
 146                 ulong old_gpecon = gpio->PGCON;
 147 #endif
 148                 /* bus still busy probably by (most) previously interrupted transfer */
 149
 150 #ifdef CONFIG_S3C2410
 151                 /* set I2CSDA and I2CSCL (GPE15, GPE14) to GPIO */
 152                 gpio->GPECON = (gpio->GPECON & ~0xF0000000) | 0x10000000;
 153 #endif
 154 #ifdef CONFIG_S3C2400
 155                 /* set I2CSDA and I2CSCL (PG5, PG6) to GPIO */
 156                 gpio->PGCON = (gpio->PGCON & ~0x00003c00) | 0x00001000;
 157 #endif
 158
 159                 /* toggle I2CSCL until bus idle */
 160                 SetI2CSCL (0);
 161                 udelay (1000);
 162                 i = 10;
 163                 while ((i > 0) && (GetI2CSDA () != 1)) {
 164                         SetI2CSCL (1);
 165                         udelay (1000);
 166                         SetI2CSCL (0);
 167                         udelay (1000);
 168                         i--;
 169                 }
 170                 SetI2CSCL (1);
 171                 udelay (1000);
 172
 173                 /* restore pin functions */
 174 #ifdef CONFIG_S3C2410
 175                 gpio->GPECON = old_gpecon;
 176 #endif
 177 #ifdef CONFIG_S3C2400
 178                 gpio->PGCON = old_gpecon;
 179 #endif
 180         }
 181
 182         /* calculate prescaler and divisor values */
 183         freq = get_PCLK ();
 184         if ((freq / pres / (16 + 1)) > speed)
 185                 /* set prescaler to 512 */
 186                 pres = 512;
 187
 188         div = 0;
 189         while ((freq / pres / (div + 1)) > speed)
 190                 div++;
 191
 192         /* set prescaler, divisor according to freq, also set
 193          * ACKGEN, IRQ */
 194         i2c->IICCON = (div & 0x0F) | 0xA0 | ((pres == 512) ? 0x40 : 0);
 195
 196         /* init to SLAVE REVEIVE and set slaveaddr */
 197         i2c->IICSTAT = 0;
 198         i2c->IICADD = slaveadd;
 199         /* program Master Transmit (and implicit STOP) */
 200         i2c->IICSTAT = I2C_MODE_MT | I2C_TXRX_ENA;
 201
 202 }
 203
 204 /*
 205  * cmd_type is 0 for write, 1 for read.
 206  *
 207  * addr_len can take any value from 0-255, it is only limited
 208  * by the char, we could make it larger if needed. If it is
 209  * 0 we skip the address write cycle.
 210  */
 211 static
 212 int i2c_transfer (unsigned char cmd_type,
 213                   unsigned char chip,
 214                   unsigned char addr[],
 215                   unsigned char addr_len,
 216                   unsigned char data[], unsigned short data_len)
 217 {
 218         S3C24X0_I2C *const i2c = S3C24X0_GetBase_I2C ();
 219         int i, status, result;
 220
 221         if (data == 0 || data_len == 0) {
 222                 /*Don't support data transfer of no length or to address 0 */
 223                 printf ("i2c_transfer: bad call\n");
 224                 return I2C_NOK;
 225         }
 226
 227         /* Check I2C bus idle */
 228         i = I2C_TIMEOUT * 1000;
 229         status = i2c->IICSTAT;
 230         while ((i > 0) && (status & I2CSTAT_BSY)) {
 231                 udelay (1000);
 232                 status = i2c->IICSTAT;
 233                 i--;
 234         }
 235
 236         if (status & I2CSTAT_BSY)
 237                 return I2C_NOK_TOUT;
 238
 239         i2c->IICCON |= 0x80;
 240         result = I2C_OK;
 241
 242         switch (cmd_type) {
 243         case I2C_WRITE:
 244                 if (addr && addr_len) {
 245                         i2c->IICDS = chip;
 246                         /* send START */
 247                         i2c->IICSTAT = I2C_MODE_MT | I2C_TXRX_ENA | I2C_START_STOP;
 248                         i = 0;
 249                         while ((i < addr_len) && (result == I2C_OK)) {
 250                                 result = WaitForXfer ();
 251                                 i2c->IICDS = addr[i];
 252                                 ReadWriteByte ();
 253                                 i++;
 254                         }
 255                         i = 0;
 256                         while ((i < data_len) && (result == I2C_OK)) {
 257                                 result = WaitForXfer ();
 258                                 i2c->IICDS = data[i];
 259                                 ReadWriteByte ();
 260                                 i++;
 261                         }
 262                 } else {
 263                         i2c->IICDS = chip;
 264                         /* send START */
 265                         i2c->IICSTAT = I2C_MODE_MT | I2C_TXRX_ENA | I2C_START_STOP;
 266                         i = 0;
 267                         while ((i < data_len) && (result = I2C_OK)) {
 268                                 result = WaitForXfer ();
 269                                 i2c->IICDS = data[i];
 270                                 ReadWriteByte ();
 271                                 i++;
 272                         }
 273                 }
 274
 275                 if (result == I2C_OK)
 276                         result = WaitForXfer ();
 277
 278                 /* send STOP */
 279                 i2c->IICSTAT = I2C_MODE_MR | I2C_TXRX_ENA;
 280                 ReadWriteByte ();
 281                 break;
 282
 283         case I2C_READ:
 284                 if (addr && addr_len) {
 285                         i2c->IICSTAT = I2C_MODE_MT | I2C_TXRX_ENA;
 286                         i2c->IICDS = chip;
 287                         /* send START */
 288                         i2c->IICSTAT |= I2C_START_STOP;
 289                         result = WaitForXfer ();
 290                         if (IsACK ()) {
 291                                 i = 0;
 292                                 while ((i < addr_len) && (result == I2C_OK)) {
 293                                         i2c->IICDS = addr[i];
 294                                         ReadWriteByte ();
 295                                         result = WaitForXfer ();
 296                                         i++;
 297                                 }
 298
 299                                 i2c->IICDS = chip;
 300                                 /* resend START */
 301                                 i2c->IICSTAT =  I2C_MODE_MR | I2C_TXRX_ENA |
 302                                                 I2C_START_STOP;
 303                                 ReadWriteByte ();
 304                                 result = WaitForXfer ();
 305                                 i = 0;
 306                                 while ((i < data_len) && (result == I2C_OK)) {
 307                                         /* disable ACK for final READ */
 308                                         if (i == data_len - 1)
 309                                                 i2c->IICCON &= ~0x80;
 310                                         ReadWriteByte ();
 311                                         result = WaitForXfer ();
 312                                         data[i] = i2c->IICDS;
 313                                         i++;
 314                                 }
 315                         } else {
 316                                 result = I2C_NACK;
 317                         }
 318
 319                 } else {
 320                         i2c->IICSTAT = I2C_MODE_MR | I2C_TXRX_ENA;
 321                         i2c->IICDS = chip;
 322                         /* send START */
 323                         i2c->IICSTAT |= I2C_START_STOP;
 324                         result = WaitForXfer ();
 325
 326                         if (IsACK ()) {
 327                                 i = 0;
 328                                 while ((i < data_len) && (result == I2C_OK)) {
 329                                         /* disable ACK for final READ */
 330                                         if (i == data_len - 1)
 331                                                 i2c->IICCON &= ~0x80;
 332                                         ReadWriteByte ();
 333                                         result = WaitForXfer ();
 334                                         data[i] = i2c->IICDS;
 335                                         i++;
 336                                 }
 337                         } else {
 338                                 result = I2C_NACK;
 339                         }
 340                 }
 341
 342                 /* send STOP */
 343                 i2c->IICSTAT = I2C_MODE_MR | I2C_TXRX_ENA;
 344                 ReadWriteByte ();
 345                 break;
 346
 347         default:
 348                 printf ("i2c_transfer: bad call\n");
 349                 result = I2C_NOK;
 350                 break;
 351         }
 352
 353         return (result);
 354 }
 355
 356 int i2c_probe (uchar chip)
 357 {
 358         uchar buf[1];
 359
 360         buf[0] = 0;
 361
 362         /*
 363          * What is needed is to send the chip address and verify that the
 364          * address was <ACK>ed (i.e. there was a chip at that address which
 365          * drove the data line low).
 366          */
 367         return (i2c_transfer (I2C_READ, chip << 1, 0, 0, buf, 1) != I2C_OK);
 368 }
 369
 370 int i2c_read (uchar chip, uint addr, int alen, uchar * buffer, int len)
 371 {
 372         uchar xaddr[4];
 373         int ret;
 374
 375         if (alen > 4) {
 376                 printf ("I2C read: addr len %d not supported\n", alen);
 377                 return 1;
 378         }
 379
 380         if (alen > 0) {
 381                 xaddr[0] = (addr >> 24) & 0xFF;
 382                 xaddr[1] = (addr >> 16) & 0xFF;
 383                 xaddr[2] = (addr >> 8) & 0xFF;
 384                 xaddr[3] = addr & 0xFF;
 385         }
 386
 387 #ifdef CFG_I2C_EEPROM_ADDR_OVERFLOW
 388         /*
 389          * EEPROM chips that implement "address overflow" are ones
 390          * like Catalyst 24WC04/08/16 which has 9/10/11 bits of
 391          * address and the extra bits end up in the "chip address"
 392          * bit slots. This makes a 24WC08 (1Kbyte) chip look like
 393          * four 256 byte chips.
 394          *
 395          * Note that we consider the length of the address field to
 396          * still be one byte because the extra address bits are
 397          * hidden in the chip address.
 398          */
 399         if (alen > 0)
 400                 chip |= ((addr >> (alen * 8)) & CFG_I2C_EEPROM_ADDR_OVERFLOW);
 401 #endif
 402         if ((ret =
 403              i2c_transfer (I2C_READ, chip << 1, &xaddr[4 - alen], alen,
 404                            buffer, len)) != 0) {
 405                 printf ("I2c read: failed %d\n", ret);
 406                 return 1;
 407         }
 408         return 0;
 409 }
 410
 411 int i2c_write (uchar chip, uint addr, int alen, uchar * buffer, int len)
 412 {
 413         uchar xaddr[4];
 414
 415         if (alen > 4) {
 416                 printf ("I2C write: addr len %d not supported\n", alen);
 417                 return 1;
 418         }
 419
 420         if (alen > 0) {
 421                 xaddr[0] = (addr >> 24) & 0xFF;
 422                 xaddr[1] = (addr >> 16) & 0xFF;
 423                 xaddr[2] = (addr >> 8) & 0xFF;
 424                 xaddr[3] = addr & 0xFF;
 425         }
 426 #ifdef CFG_I2C_EEPROM_ADDR_OVERFLOW
 427         /*
 428          * EEPROM chips that implement "address overflow" are ones
 429          * like Catalyst 24WC04/08/16 which has 9/10/11 bits of
 430          * address and the extra bits end up in the "chip address"
 431          * bit slots. This makes a 24WC08 (1Kbyte) chip look like
 432          * four 256 byte chips.
 433          *
 434          * Note that we consider the length of the address field to
 435          * still be one byte because the extra address bits are
 436          * hidden in the chip address.
 437          */
 438         if (alen > 0)
 439                 chip |= ((addr >> (alen * 8)) & CFG_I2C_EEPROM_ADDR_OVERFLOW);
 440 #endif
 441         return (i2c_transfer
 442                 (I2C_WRITE, chip << 1, &xaddr[4 - alen], alen, buffer,
 443                  len) != 0);
 444 }
 445 #endif  /* CONFIG_HARD_I2C */
 446
 447 #endif /* CONFIG_DRIVER_S3C24X0_I2C */