drivers/i2c/i2c-algo-pcf.c

   1 /* ------------------------------------------------------------------------- */
   2 /* i2c-algo-pcf.c i2c driver algorithms for PCF8584 adapters                 */
   3 /* ------------------------------------------------------------------------- */
   4 /*   Copyright (C) 1995-1997 Simon G. Vogl
   5                    1998-2000 Hans Berglund
   6
   7     This program is free software; you can redistribute it and/or modify
   8     it under the terms of the GNU General Public License as published by
   9     the Free Software Foundation; either version 2 of the License, or
  10     (at your option) any later version.
  11
  12     This program is distributed in the hope that it will be useful,
  13     but WITHOUT ANY WARRANTY; without even the implied warranty of
  14     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15     GNU General Public License for more details.
  16
  17     You should have received a copy of the GNU General Public License
  18     along with this program; if not, write to the Free Software
  19     Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.                */
  20 /* ------------------------------------------------------------------------- */
  21
  22 /* With some changes from Kyösti Mälkki <kmalkki@cc.hut.fi> and
  23    Frodo Looijaard <frodol@dds.nl> ,and also from Martin Bailey
  24    <mbailey@littlefeet-inc.com> */
  25
  26 /* Partially rewriten by Oleg I. Vdovikin <vdovikin@jscc.ru> to handle multiple
  27    messages, proper stop/repstart signaling during receive,
  28    added detect code */
  29
  30 #include <linux/kernel.h>
  31 #include <linux/module.h>
  32 #include <linux/delay.h>
  33 #include <linux/slab.h>
  34 #include <linux/init.h>
  35 #include <linux/errno.h>
  36 #include <linux/sched.h>
  37 #include <linux/i2c.h>
  38 #include <linux/i2c-algo-pcf.h>
  39 #include "i2c-pcf8584.h"
  40
  41
  42 /* ----- global defines ----------------------------------------------- */
  43 #define DEB(x) if (i2c_debug>=1) x
  44 #define DEB2(x) if (i2c_debug>=2) x
  45 #define DEB3(x) if (i2c_debug>=3) x /* print several statistical values*/
  46 #define DEBPROTO(x) if (i2c_debug>=9) x;
  47         /* debug the protocol by showing transferred bits */
  48 #define DEF_TIMEOUT 16
  49
  50 /* module parameters:
  51  */
  52 static int i2c_debug=0;
  53 static int pcf_scan=0;  /* have a look at what's hanging 'round         */
  54
  55 /* --- setting states on the bus with the right timing: --------------- */
  56
  57 #define set_pcf(adap, ctl, val) adap->setpcf(adap->data, ctl, val)
  58 #define get_pcf(adap, ctl) adap->getpcf(adap->data, ctl)
  59 #define get_own(adap) adap->getown(adap->data)
  60 #define get_clock(adap) adap->getclock(adap->data)
  61 #define i2c_outb(adap, val) adap->setpcf(adap->data, 0, val)
  62 #define i2c_inb(adap) adap->getpcf(adap->data, 0)
  63
  64 /* --- other auxiliary functions -------------------------------------- */
  65
  66 static void i2c_start(struct i2c_algo_pcf_data *adap)
  67 {
  68         DEBPROTO(printk("S "));
  69         set_pcf(adap, 1, I2C_PCF_START);
  70 }
  71
  72 static void i2c_repstart(struct i2c_algo_pcf_data *adap)
  73 {
  74         DEBPROTO(printk(" Sr "));
  75         set_pcf(adap, 1, I2C_PCF_REPSTART);
  76 }
  77
  78
  79 static void i2c_stop(struct i2c_algo_pcf_data *adap)
  80 {
  81         DEBPROTO(printk("P\n"));
  82         set_pcf(adap, 1, I2C_PCF_STOP);
  83 }
  84
  85
  86 static int wait_for_bb(struct i2c_algo_pcf_data *adap) {
  87
  88         int timeout = DEF_TIMEOUT;
  89         int status;
  90
  91         status = get_pcf(adap, 1);
  92 #ifndef STUB_I2C
  93         while (timeout-- && !(status & I2C_PCF_BB)) {
  94                 udelay(100); /* wait for 100 us */
  95                 status = get_pcf(adap, 1);
  96         }
  97 #endif
  98         if (timeout <= 0) {
  99                 printk(KERN_ERR "Timeout waiting for Bus Busy\n");
 100         }
 101
 102         return (timeout<=0);
 103 }
 104
 105
 106 static inline void pcf_sleep(unsigned long timeout)
 107 {
 108         schedule_timeout( timeout * HZ);
 109 }
 110
 111
 112 static int wait_for_pin(struct i2c_algo_pcf_data *adap, int *status) {
 113
 114         int timeout = DEF_TIMEOUT;
 115
 116         *status = get_pcf(adap, 1);
 117 #ifndef STUB_I2C
 118         while (timeout-- && (*status & I2C_PCF_PIN)) {
 119                 adap->waitforpin();
 120                 *status = get_pcf(adap, 1);
 121         }
 122 #endif
 123         if (timeout <= 0)
 124                 return(-1);
 125         else
 126                 return(0);
 127 }
 128
 129 /*
 130  * This should perform the 'PCF8584 initialization sequence' as described
 131  * in the Philips IC12 data book (1995, Aug 29).
 132  * There should be a 30 clock cycle wait after reset, I assume this
 133  * has been fulfilled.
 134  * There should be a delay at the end equal to the longest I2C message
 135  * to synchronize the BB-bit (in multimaster systems). How long is
 136  * this? I assume 1 second is always long enough.
 137  *
 138  * vdovikin: added detect code for PCF8584
 139  */
 140 static int pcf_init_8584 (struct i2c_algo_pcf_data *adap)
 141 {
 142         unsigned char temp;
 143
 144         DEB3(printk(KERN_DEBUG "i2c-algo-pcf.o: PCF state 0x%02x\n", get_pcf(adap, 1)));
 145
 146         /* S1=0x80: S0 selected, serial interface off */
 147         set_pcf(adap, 1, I2C_PCF_PIN);
 148         /* check to see S1 now used as R/W ctrl -
 149            PCF8584 does that when ESO is zero */
 150         /* PCF also resets PIN bit */
 151         if ((temp = get_pcf(adap, 1)) != (0)) {
 152                 DEB2(printk(KERN_ERR "i2c-algo-pcf.o: PCF detection failed -- can't select S0 (0x%02x).\n", temp));
 153                 return -ENXIO; /* definetly not PCF8584 */
 154         }
 155
 156         /* load own address in S0, effective address is (own << 1)      */
 157         i2c_outb(adap, get_own(adap));
 158         /* check it's realy writen */
 159         if ((temp = i2c_inb(adap)) != get_own(adap)) {
 160                 DEB2(printk(KERN_ERR "i2c-algo-pcf.o: PCF detection failed -- can't set S0 (0x%02x).\n", temp));
 161                 return -ENXIO;
 162         }
 163
 164         /* S1=0xA0, next byte in S2                                     */
 165         set_pcf(adap, 1, I2C_PCF_PIN | I2C_PCF_ES1);
 166         /* check to see S2 now selected */
 167         if ((temp = get_pcf(adap, 1)) != I2C_PCF_ES1) {
 168                 DEB2(printk(KERN_ERR "i2c-algo-pcf.o: PCF detection failed -- can't select S2 (0x%02x).\n", temp));
 169                 return -ENXIO;
 170         }
 171
 172         /* load clock register S2                                       */
 173         i2c_outb(adap, get_clock(adap));
 174         /* check it's realy writen, the only 5 lowest bits does matter */
 175         if (((temp = i2c_inb(adap)) & 0x1f) != get_clock(adap)) {
 176                 DEB2(printk(KERN_ERR "i2c-algo-pcf.o: PCF detection failed -- can't set S2 (0x%02x).\n", temp));
 177                 return -ENXIO;
 178         }
 179
 180         /* Enable serial interface, idle, S0 selected                   */
 181         set_pcf(adap, 1, I2C_PCF_IDLE);
 182
 183         /* check to see PCF is realy idled and we can access status register */
 184         if ((temp = get_pcf(adap, 1)) != (I2C_PCF_PIN | I2C_PCF_BB)) {
 185                 DEB2(printk(KERN_ERR "i2c-algo-pcf.o: PCF detection failed -- can't select S1` (0x%02x).\n", temp));
 186                 return -ENXIO;
 187         }
 188
 189         printk(KERN_DEBUG "i2c-algo-pcf.o: deteted and initialized PCF8584.\n");
 190
 191         return 0;
 192 }
 193
 194
 195 /* ----- Utility functions
 196  */
 197
 198 static inline int try_address(struct i2c_algo_pcf_data *adap,
 199                        unsigned char addr, int retries)
 200 {
 201         int i, status, ret = -1;
 202         for (i=0;i<retries;i++) {
 203                 i2c_outb(adap, addr);
 204                 i2c_start(adap);
 205                 status = get_pcf(adap, 1);
 206                 if (wait_for_pin(adap, &status) >= 0) {
 207                         if ((status & I2C_PCF_LRB) == 0) {
 208                                 i2c_stop(adap);
 209                                 break;  /* success! */
 210                         }
 211                 }
 212                 i2c_stop(adap);
 213                 udelay(adap->udelay);
 214         }
 215         DEB2(if (i) printk(KERN_DEBUG "i2c-algo-pcf.o: needed %d retries for %d\n",i,
 216                            addr));
 217         return ret;
 218 }
 219
 220
 221 static int pcf_sendbytes(struct i2c_adapter *i2c_adap, const char *buf,
 222                          int count, int last)
 223 {
 224         struct i2c_algo_pcf_data *adap = i2c_adap->algo_data;
 225         int wrcount, status, timeout;
 226
 227         for (wrcount=0; wrcount<count; ++wrcount) {
 228                 DEB2(printk(KERN_DEBUG "i2c-algo-pcf.o: %s i2c_write: writing %2.2X\n",
 229                       i2c_adap->name, buf[wrcount]&0xff));
 230                 i2c_outb(adap, buf[wrcount]);
 231                 timeout = wait_for_pin(adap, &status);
 232                 if (timeout) {
 233                         i2c_stop(adap);
 234                         printk(KERN_ERR "i2c-algo-pcf.o: %s i2c_write: "
 235                                "error - timeout.\n", i2c_adap->name);
 236                         return -EREMOTEIO; /* got a better one ?? */
 237                 }
 238 #ifndef STUB_I2C
 239                 if (status & I2C_PCF_LRB) {
 240                         i2c_stop(adap);
 241                         printk(KERN_ERR "i2c-algo-pcf.o: %s i2c_write: "
 242                                "error - no ack.\n", i2c_adap->name);
 243                         return -EREMOTEIO; /* got a better one ?? */
 244                 }
 245 #endif
 246         }
 247         if (last) {
 248                 i2c_stop(adap);
 249         }
 250         else {
 251                 i2c_repstart(adap);
 252         }
 253
 254         return (wrcount);
 255 }
 256
 257
 258 static int pcf_readbytes(struct i2c_adapter *i2c_adap, char *buf,
 259                          int count, int last)
 260 {
 261         int i, status;
 262         struct i2c_algo_pcf_data *adap = i2c_adap->algo_data;
 263
 264         /* increment number of bytes to read by one -- read dummy byte */
 265         for (i = 0; i <= count; i++) {
 266
 267                 if (wait_for_pin(adap, &status)) {
 268                         i2c_stop(adap);
 269                         printk(KERN_ERR "i2c-algo-pcf.o: pcf_readbytes timed out.\n");
 270                         return (-1);
 271                 }
 272
 273 #ifndef STUB_I2C
 274                 if ((status & I2C_PCF_LRB) && (i != count)) {
 275                         i2c_stop(adap);
 276                         printk(KERN_ERR "i2c-algo-pcf.o: i2c_read: i2c_inb, No ack.\n");
 277                         return (-1);
 278                 }
 279 #endif
 280
 281                 if (i == count - 1) {
 282                         set_pcf(adap, 1, I2C_PCF_ESO);
 283                 } else
 284                 if (i == count) {
 285                         if (last) {
 286                                 i2c_stop(adap);
 287                         } else {
 288                                 i2c_repstart(adap);
 289                         }
 290                 };
 291
 292                 if (i) {
 293                         buf[i - 1] = i2c_inb(adap);
 294                 } else {
 295                         i2c_inb(adap); /* dummy read */
 296                 }
 297         }
 298
 299         return (i - 1);
 300 }
 301
 302
 303 static inline int pcf_doAddress(struct i2c_algo_pcf_data *adap,
 304                                 struct i2c_msg *msg, int retries)
 305 {
 306         unsigned short flags = msg->flags;
 307         unsigned char addr;
 308         int ret;
 309         if ( (flags & I2C_M_TEN)  ) {
 310                 /* a ten bit address */
 311                 addr = 0xf0 | (( msg->addr >> 7) & 0x03);
 312                 DEB2(printk(KERN_DEBUG "addr0: %d\n",addr));
 313                 /* try extended address code...*/
 314                 ret = try_address(adap, addr, retries);
 315                 if (ret!=1) {
 316                         printk(KERN_ERR "died at extended address code.\n");
 317                         return -EREMOTEIO;
 318                 }
 319                 /* the remaining 8 bit address */
 320                 i2c_outb(adap,msg->addr & 0x7f);
 321 /* Status check comes here */
 322                 if (ret != 1) {
 323                         printk(KERN_ERR "died at 2nd address code.\n");
 324                         return -EREMOTEIO;
 325                 }
 326                 if ( flags & I2C_M_RD ) {
 327                         i2c_repstart(adap);
 328                         /* okay, now switch into reading mode */
 329                         addr |= 0x01;
 330                         ret = try_address(adap, addr, retries);
 331                         if (ret!=1) {
 332                                 printk(KERN_ERR "died at extended address code.\n");
 333                                 return -EREMOTEIO;
 334                         }
 335                 }
 336         } else {                /* normal 7bit address  */
 337                 addr = ( msg->addr << 1 );
 338                 if (flags & I2C_M_RD )
 339                         addr |= 1;
 340                 if (flags & I2C_M_REV_DIR_ADDR )
 341                         addr ^= 1;
 342                 i2c_outb(adap, addr);
 343         }
 344         return 0;
 345 }
 346
 347 static int pcf_xfer(struct i2c_adapter *i2c_adap,
 348                     struct i2c_msg msgs[],
 349                     int num)
 350 {
 351         struct i2c_algo_pcf_data *adap = i2c_adap->algo_data;
 352         struct i2c_msg *pmsg;
 353         int i;
 354         int ret=0, timeout, status;
 355
 356
 357         /* Check for bus busy */
 358         timeout = wait_for_bb(adap);
 359         if (timeout) {
 360                 DEB2(printk(KERN_ERR "i2c-algo-pcf.o: "
 361                             "Timeout waiting for BB in pcf_xfer\n");)
 362                 return -EIO;
 363         }
 364
 365         for (i = 0;ret >= 0 && i < num; i++) {
 366                 pmsg = &msgs[i];
 367
 368                 DEB2(printk(KERN_DEBUG "i2c-algo-pcf.o: Doing %s %d bytes to 0x%02x - %d of %d messages\n",
 369                      pmsg->flags & I2C_M_RD ? "read" : "write",
 370                      pmsg->len, pmsg->addr, i + 1, num);)
 371
 372                 ret = pcf_doAddress(adap, pmsg, i2c_adap->retries);
 373
 374                 /* Send START */
 375                 if (i == 0) {
 376                         i2c_start(adap);
 377                 }
 378
 379                 /* Wait for PIN (pending interrupt NOT) */
 380                 timeout = wait_for_pin(adap, &status);
 381                 if (timeout) {
 382                         i2c_stop(adap);
 383                         DEB2(printk(KERN_ERR "i2c-algo-pcf.o: Timeout waiting "
 384                                     "for PIN(1) in pcf_xfer\n");)
 385                         return (-EREMOTEIO);
 386                 }
 387
 388 #ifndef STUB_I2C
 389                 /* Check LRB (last rcvd bit - slave ack) */
 390                 if (status & I2C_PCF_LRB) {
 391                         i2c_stop(adap);
 392                         DEB2(printk(KERN_ERR "i2c-algo-pcf.o: No LRB(1) in pcf_xfer\n");)
 393                         return (-EREMOTEIO);
 394                 }
 395 #endif
 396
 397                 DEB3(printk(KERN_DEBUG "i2c-algo-pcf.o: Msg %d, addr=0x%x, flags=0x%x, len=%d\n",
 398                             i, msgs[i].addr, msgs[i].flags, msgs[i].len);)
 399
 400                 /* Read */
 401                 if (pmsg->flags & I2C_M_RD) {
 402                         /* read bytes into buffer*/
 403                         ret = pcf_readbytes(i2c_adap, pmsg->buf, pmsg->len,
 404                                             (i + 1 == num));
 405
 406                         if (ret != pmsg->len) {
 407                                 DEB2(printk(KERN_DEBUG "i2c-algo-pcf.o: fail: "
 408                                             "only read %d bytes.\n",ret));
 409                         } else {
 410                                 DEB2(printk(KERN_DEBUG "i2c-algo-pcf.o: read %d bytes.\n",ret));
 411                         }
 412                 } else { /* Write */
 413                         ret = pcf_sendbytes(i2c_adap, pmsg->buf, pmsg->len,
 414                                             (i + 1 == num));
 415
 416                         if (ret != pmsg->len) {
 417                                 DEB2(printk(KERN_DEBUG "i2c-algo-pcf.o: fail: "
 418                                             "only wrote %d bytes.\n",ret));
 419                         } else {
 420                                 DEB2(printk(KERN_DEBUG "i2c-algo-pcf.o: wrote %d bytes.\n",ret));
 421                         }
 422                 }
 423         }
 424
 425         return (i);
 426 }
 427
 428 static int algo_control(struct i2c_adapter *adapter,
 429         unsigned int cmd, unsigned long arg)
 430 {
 431         return 0;
 432 }
 433
 434 static u32 pcf_func(struct i2c_adapter *adap)
 435 {
 436         return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL |
 437                I2C_FUNC_10BIT_ADDR | I2C_FUNC_PROTOCOL_MANGLING;
 438 }
 439
 440 /* -----exported algorithm data: -------------------------------------  */
 441
 442 static struct i2c_algorithm pcf_algo = {
 443         "PCF8584 algorithm",
 444         I2C_ALGO_PCF,
 445         pcf_xfer,
 446         NULL,
 447         NULL,                           /* slave_xmit           */
 448         NULL,                           /* slave_recv           */
 449         algo_control,                   /* ioctl                */
 450         pcf_func,                       /* functionality        */
 451 };
 452
 453 /*
 454  * registering functions to load algorithms at runtime
 455  */
 456 int i2c_pcf_add_bus(struct i2c_adapter *adap)
 457 {
 458         int i, status;
 459         struct i2c_algo_pcf_data *pcf_adap = adap->algo_data;
 460
 461         DEB2(printk(KERN_DEBUG "i2c-algo-pcf.o: hw routines for %s registered.\n",
 462                     adap->name));
 463
 464         /* register new adapter to i2c module... */
 465
 466         adap->id |= pcf_algo.id;
 467         adap->algo = &pcf_algo;
 468
 469         adap->timeout = 100;            /* default values, should       */
 470         adap->retries = 3;              /* be replaced by defines       */
 471
 472         if ((i = pcf_init_8584(pcf_adap))) {
 473                 return i;
 474         }
 475
 476 #ifdef MODULE
 477         MOD_INC_USE_COUNT;
 478 #endif
 479
 480         /* scan bus */
 481         if (pcf_scan) {
 482                 printk(KERN_INFO " i2c-algo-pcf.o: scanning bus %s.\n",
 483                        adap->name);
 484                 for (i = 0x00; i < 0xff; i+=2) {
 485                         if (wait_for_bb(pcf_adap)) {
 486                         printk(KERN_INFO " i2c-algo-pcf.o: scanning bus %s - TIMEOUTed.\n",
 487                            adap->name);
 488                             break;
 489                         }
 490                         i2c_outb(pcf_adap, i);
 491                         i2c_start(pcf_adap);
 492                         if ((wait_for_pin(pcf_adap, &status) >= 0) &&
 493                             ((status & I2C_PCF_LRB) == 0)) {
 494                                 printk("(%02x)",i>>1);
 495                         } else {
 496                                 printk(".");
 497                         }
 498                         i2c_stop(pcf_adap);
 499                         udelay(pcf_adap->udelay);
 500                 }
 501                 printk("\n");
 502         }
 503
 504         return i2c_add_adapter(adap);
 505 }
 506
 507
 508 int i2c_pcf_del_bus(struct i2c_adapter *adap)
 509 {
 510         int res;
 511         if ((res = i2c_del_adapter(adap)) < 0)
 512                 return res;
 513         DEB2(printk("i2c-algo-pcf.o: adapter unregistered: %s\n",adap->name));
 514
 515 #ifdef MODULE
 516         MOD_DEC_USE_COUNT;
 517 #endif
 518         return 0;
 519 }
 520
 521 int __init i2c_algo_pcf_init (void)
 522 {
 523         printk("i2c-algo-pcf.o: i2c pcf8584 algorithm module\n");
 524         return 0;
 525 }
 526
 527 EXPORT_SYMBOL(i2c_pcf_add_bus);
 528 EXPORT_SYMBOL(i2c_pcf_del_bus);
 529
 530 #ifdef MODULE
 531 MODULE_AUTHOR("Hans Berglund <hb@spacetec.no>");
 532 MODULE_DESCRIPTION("I2C-Bus PCF8584 algorithm");
 533 MODULE_LICENSE("GPL");
 534
 535 MODULE_PARM(pcf_scan, "i");
 536 MODULE_PARM(i2c_debug,"i");
 537
 538 MODULE_PARM_DESC(pcf_scan, "Scan for active chips on the bus");
 539 MODULE_PARM_DESC(i2c_debug,
 540         "debug level - 0 off; 1 normal; 2,3 more verbose; 9 pcf-protocol");
 541
 542
 543 int init_module(void)
 544 {
 545         return i2c_algo_pcf_init();
 546 }
 547
 548 void cleanup_module(void)
 549 {
 550 }
 551 #endif