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/version.h>
  35 #include <linux/init.h>
  36 #include <asm/uaccess.h>
  37 #include <linux/ioport.h>
  38 #include <linux/errno.h>
  39 #include <linux/sched.h>
  40
  41 #include <linux/i2c.h>
  42 #include <linux/i2c-algo-pcf.h>
  43 #include "i2c-pcf8584.h"
  44
  45 /* ----- global defines ----------------------------------------------- */
  46 #define DEB(x) if (i2c_debug>=1) x
  47 #define DEB2(x) if (i2c_debug>=2) x
  48 #define DEB3(x) if (i2c_debug>=3) x /* print several statistical values*/
  49 #define DEBPROTO(x) if (i2c_debug>=9) x;
  50         /* debug the protocol by showing transferred bits */
  51 #define DEF_TIMEOUT 16
  52
  53 /* module parameters:
  54  */
  55 static int i2c_debug=0;
  56 static int pcf_scan=0;  /* have a look at what's hanging 'round         */
  57
  58 /* --- setting states on the bus with the right timing: --------------- */
  59
  60 #define set_pcf(adap, ctl, val) adap->setpcf(adap->data, ctl, val)
  61 #define get_pcf(adap, ctl) adap->getpcf(adap->data, ctl)
  62 #define get_own(adap) adap->getown(adap->data)
  63 #define get_clock(adap) adap->getclock(adap->data)
  64 #define i2c_outb(adap, val) adap->setpcf(adap->data, 0, val)
  65 #define i2c_inb(adap) adap->getpcf(adap->data, 0)
  66
  67 /* --- other auxiliary functions -------------------------------------- */
  68
  69 static void i2c_start(struct i2c_algo_pcf_data *adap)
  70 {
  71         DEBPROTO(printk("S "));
  72         set_pcf(adap, 1, I2C_PCF_START);
  73 }
  74
  75 static void i2c_repstart(struct i2c_algo_pcf_data *adap)
  76 {
  77         DEBPROTO(printk(" Sr "));
  78         set_pcf(adap, 1, I2C_PCF_REPSTART);
  79 }
  80
  81
  82 static void i2c_stop(struct i2c_algo_pcf_data *adap)
  83 {
  84         DEBPROTO(printk("P\n"));
  85         set_pcf(adap, 1, I2C_PCF_STOP);
  86 }
  87
  88
  89 static int wait_for_bb(struct i2c_algo_pcf_data *adap) {
  90
  91         int timeout = DEF_TIMEOUT;
  92         int status;
  93
  94         status = get_pcf(adap, 1);
  95 #ifndef STUB_I2C
  96         while (timeout-- && !(status & I2C_PCF_BB)) {
  97                 udelay(100); /* wait for 100 us */
  98                 status = get_pcf(adap, 1);
  99         }
 100 #endif
 101         if (timeout <= 0) {
 102                 printk("Timeout waiting for Bus Busy\n");
 103         }
 104
 105         return (timeout<=0);
 106 }
 107
 108
 109 static inline void pcf_sleep(unsigned long timeout)
 110 {
 111         schedule_timeout( timeout * HZ);
 112 }
 113
 114
 115 static int wait_for_pin(struct i2c_algo_pcf_data *adap, int *status) {
 116
 117         int timeout = DEF_TIMEOUT;
 118
 119         *status = get_pcf(adap, 1);
 120 #ifndef STUB_I2C
 121         while (timeout-- && (*status & I2C_PCF_PIN)) {
 122                 adap->waitforpin();
 123                 *status = get_pcf(adap, 1);
 124         }
 125 #endif
 126         if (timeout <= 0)
 127                 return(-1);
 128         else
 129                 return(0);
 130 }
 131
 132 /*
 133  * This should perform the 'PCF8584 initialization sequence' as described
 134  * in the Philips IC12 data book (1995, Aug 29).
 135  * There should be a 30 clock cycle wait after reset, I assume this
 136  * has been fulfilled.
 137  * There should be a delay at the end equal to the longest I2C message
 138  * to synchronize the BB-bit (in multimaster systems). How long is
 139  * this? I assume 1 second is always long enough.
 140  *
 141  * vdovikin: added detect code for PCF8584
 142  */
 143 static int pcf_init_8584 (struct i2c_algo_pcf_data *adap)
 144 {
 145         unsigned char temp;
 146
 147         DEB3(printk("i2c-algo-pcf.o: PCF state 0x%02x\n", get_pcf(adap, 1)));
 148
 149         /* S1=0x80: S0 selected, serial interface off */
 150         set_pcf(adap, 1, I2C_PCF_PIN);
 151         /* check to see S1 now used as R/W ctrl -
 152            PCF8584 does that when ESO is zero */
 153         /* PCF also resets PIN bit */
 154         if ((temp = get_pcf(adap, 1)) != (0)) {
 155                 DEB2(printk("i2c-algo-pcf.o: PCF detection failed -- can't select S0 (0x%02x).\n", temp));
 156                 return -ENXIO; /* definetly not PCF8584 */
 157         }
 158
 159         /* load own address in S0, effective address is (own << 1)      */
 160         i2c_outb(adap, get_own(adap));
 161         /* check it's realy writen */
 162         if ((temp = i2c_inb(adap)) != get_own(adap)) {
 163                 DEB2(printk("i2c-algo-pcf.o: PCF detection failed -- can't set S0 (0x%02x).\n", temp));
 164                 return -ENXIO;
 165         }
 166
 167         /* S1=0xA0, next byte in S2                                     */
 168         set_pcf(adap, 1, I2C_PCF_PIN | I2C_PCF_ES1);
 169         /* check to see S2 now selected */
 170         if ((temp = get_pcf(adap, 1)) != I2C_PCF_ES1) {
 171                 DEB2(printk("i2c-algo-pcf.o: PCF detection failed -- can't select S2 (0x%02x).\n", temp));
 172                 return -ENXIO;
 173         }
 174
 175         /* load clock register S2                                       */
 176         i2c_outb(adap, get_clock(adap));
 177         /* check it's realy writen, the only 5 lowest bits does matter */
 178         if (((temp = i2c_inb(adap)) & 0x1f) != get_clock(adap)) {
 179                 DEB2(printk("i2c-algo-pcf.o: PCF detection failed -- can't set S2 (0x%02x).\n", temp));
 180                 return -ENXIO;
 181         }
 182
 183         /* Enable serial interface, idle, S0 selected                   */
 184         set_pcf(adap, 1, I2C_PCF_IDLE);
 185
 186         /* check to see PCF is realy idled and we can access status register */
 187         if ((temp = get_pcf(adap, 1)) != (I2C_PCF_PIN | I2C_PCF_BB)) {
 188                 DEB2(printk("i2c-algo-pcf.o: PCF detection failed -- can't select S1` (0x%02x).\n", temp));
 189                 return -ENXIO;
 190         }
 191
 192         printk("i2c-algo-pcf.o: deteted and initialized PCF8584.\n");
 193
 194         return 0;
 195 }
 196
 197
 198 /* ----- Utility functions
 199  */
 200
 201 static inline int try_address(struct i2c_algo_pcf_data *adap,
 202                        unsigned char addr, int retries)
 203 {
 204         int i, status, ret = -1;
 205         for (i=0;i<retries;i++) {
 206                 i2c_outb(adap, addr);
 207                 i2c_start(adap);
 208                 status = get_pcf(adap, 1);
 209                 if (wait_for_pin(adap, &status) >= 0) {
 210                         if ((status & I2C_PCF_LRB) == 0) {
 211                                 i2c_stop(adap);
 212                                 break;  /* success! */
 213                         }
 214                 }
 215                 i2c_stop(adap);
 216                 udelay(adap->udelay);
 217         }
 218         DEB2(if (i) printk("i2c-algo-pcf.o: needed %d retries for %d\n",i,
 219                            addr));
 220         return ret;
 221 }
 222
 223
 224 static int pcf_sendbytes(struct i2c_adapter *i2c_adap, const char *buf,
 225                          int count, int last)
 226 {
 227         struct i2c_algo_pcf_data *adap = i2c_adap->algo_data;
 228         int wrcount, status, timeout;
 229
 230         for (wrcount=0; wrcount<count; ++wrcount) {
 231                 DEB2(printk("i2c-algo-pcf.o: %s i2c_write: writing %2.2X\n",
 232                       i2c_adap->name, buf[wrcount]&0xff));
 233                 i2c_outb(adap, buf[wrcount]);
 234                 timeout = wait_for_pin(adap, &status);
 235                 if (timeout) {
 236                         i2c_stop(adap);
 237                         printk("i2c-algo-pcf.o: %s i2c_write: "
 238                                "error - timeout.\n", i2c_adap->name);
 239                         return -EREMOTEIO; /* got a better one ?? */
 240                 }
 241 #ifndef STUB_I2C
 242                 if (status & I2C_PCF_LRB) {
 243                         i2c_stop(adap);
 244                         printk("i2c-algo-pcf.o: %s i2c_write: "
 245                                "error - no ack.\n", i2c_adap->name);
 246                         return -EREMOTEIO; /* got a better one ?? */
 247                 }
 248 #endif
 249         }
 250         if (last) {
 251                 i2c_stop(adap);
 252         }
 253         else {
 254                 i2c_repstart(adap);
 255         }
 256
 257         return (wrcount);
 258 }
 259
 260
 261 static int pcf_readbytes(struct i2c_adapter *i2c_adap, char *buf,
 262                          int count, int last)
 263 {
 264         int i, status;
 265         struct i2c_algo_pcf_data *adap = i2c_adap->algo_data;
 266
 267         /* increment number of bytes to read by one -- read dummy byte */
 268         for (i = 0; i <= count; i++) {
 269
 270                 if (wait_for_pin(adap, &status)) {
 271                         i2c_stop(adap);
 272                         printk("i2c-algo-pcf.o: pcf_readbytes timed out.\n");
 273                         return (-1);
 274                 }
 275
 276 #ifndef STUB_I2C
 277                 if ((status & I2C_PCF_LRB) && (i != count)) {
 278                         i2c_stop(adap);
 279                         printk("i2c-algo-pcf.o: i2c_read: i2c_inb, No ack.\n");
 280                         return (-1);
 281                 }
 282 #endif
 283
 284                 if (i == count - 1) {
 285                         set_pcf(adap, 1, I2C_PCF_ESO);
 286                 } else
 287                 if (i == count) {
 288                         if (last) {
 289                                 i2c_stop(adap);
 290                         } else {
 291                                 i2c_repstart(adap);
 292                         }
 293                 };
 294
 295                 if (i) {
 296                         buf[i - 1] = i2c_inb(adap);
 297                 } else {
 298                         i2c_inb(adap); /* dummy read */
 299                 }
 300         }
 301
 302         return (i - 1);
 303 }
 304
 305
 306 static inline int pcf_doAddress(struct i2c_algo_pcf_data *adap,
 307                                 struct i2c_msg *msg, int retries)
 308 {
 309         unsigned short flags = msg->flags;
 310         unsigned char addr;
 311         int ret;
 312         if ( (flags & I2C_M_TEN)  ) {
 313                 /* a ten bit address */
 314                 addr = 0xf0 | (( msg->addr >> 7) & 0x03);
 315                 DEB2(printk("addr0: %d\n",addr));
 316                 /* try extended address code...*/
 317                 ret = try_address(adap, addr, retries);
 318                 if (ret!=1) {
 319                         printk("died at extended address code.\n");
 320                         return -EREMOTEIO;
 321                 }
 322                 /* the remaining 8 bit address */
 323                 i2c_outb(adap,msg->addr & 0x7f);
 324 /* Status check comes here */
 325                 if (ret != 1) {
 326                         printk("died at 2nd address code.\n");
 327                         return -EREMOTEIO;
 328                 }
 329                 if ( flags & I2C_M_RD ) {
 330                         i2c_repstart(adap);
 331                         /* okay, now switch into reading mode */
 332                         addr |= 0x01;
 333                         ret = try_address(adap, addr, retries);
 334                         if (ret!=1) {
 335                                 printk("died at extended address code.\n");
 336                                 return -EREMOTEIO;
 337                         }
 338                 }
 339         } else {                /* normal 7bit address  */
 340                 addr = ( msg->addr << 1 );
 341                 if (flags & I2C_M_RD )
 342                         addr |= 1;
 343                 if (flags & I2C_M_REV_DIR_ADDR )
 344                         addr ^= 1;
 345                 i2c_outb(adap, addr);
 346         }
 347         return 0;
 348 }
 349
 350 static int pcf_xfer(struct i2c_adapter *i2c_adap,
 351                     struct i2c_msg msgs[],
 352                     int num)
 353 {
 354         struct i2c_algo_pcf_data *adap = i2c_adap->algo_data;
 355         struct i2c_msg *pmsg;
 356         int i;
 357         int ret=0, timeout, status;
 358
 359
 360         /* Check for bus busy */
 361         timeout = wait_for_bb(adap);
 362         if (timeout) {
 363                 DEB2(printk("i2c-algo-pcf.o: "
 364                             "Timeout waiting for BB in pcf_xfer\n");)
 365                 return -EIO;
 366         }
 367
 368         for (i = 0;ret >= 0 && i < num; i++) {
 369                 pmsg = &msgs[i];
 370
 371                 DEB2(printk("i2c-algo-pcf.o: Doing %s %d bytes to 0x%02x - %d of %d messages\n",
 372                      pmsg->flags & I2C_M_RD ? "read" : "write",
 373                      pmsg->len, pmsg->addr, i + 1, num);)
 374
 375                 ret = pcf_doAddress(adap, pmsg, i2c_adap->retries);
 376
 377                 /* Send START */
 378                 if (i == 0) {
 379                         i2c_start(adap);
 380                 }
 381
 382                 /* Wait for PIN (pending interrupt NOT) */
 383                 timeout = wait_for_pin(adap, &status);
 384                 if (timeout) {
 385                         i2c_stop(adap);
 386                         DEB2(printk("i2c-algo-pcf.o: Timeout waiting "
 387                                     "for PIN(1) in pcf_xfer\n");)
 388                         return (-EREMOTEIO);
 389                 }
 390
 391 #ifndef STUB_I2C
 392                 /* Check LRB (last rcvd bit - slave ack) */
 393                 if (status & I2C_PCF_LRB) {
 394                         i2c_stop(adap);
 395                         DEB2(printk("i2c-algo-pcf.o: No LRB(1) in pcf_xfer\n");)
 396                         return (-EREMOTEIO);
 397                 }
 398 #endif
 399
 400                 DEB3(printk("i2c-algo-pcf.o: Msg %d, addr=0x%x, flags=0x%x, len=%d\n",
 401                             i, msgs[i].addr, msgs[i].flags, msgs[i].len);)
 402
 403                 /* Read */
 404                 if (pmsg->flags & I2C_M_RD) {
 405                         /* read bytes into buffer*/
 406                         ret = pcf_readbytes(i2c_adap, pmsg->buf, pmsg->len,
 407                                             (i + 1 == num));
 408
 409                         if (ret != pmsg->len) {
 410                                 DEB2(printk("i2c-algo-pcf.o: fail: "
 411                                             "only read %d bytes.\n",ret));
 412                         } else {
 413                                 DEB2(printk("i2c-algo-pcf.o: read %d bytes.\n",ret));
 414                         }
 415                 } else { /* Write */
 416                         ret = pcf_sendbytes(i2c_adap, pmsg->buf, pmsg->len,
 417                                             (i + 1 == num));
 418
 419                         if (ret != pmsg->len) {
 420                                 DEB2(printk("i2c-algo-pcf.o: fail: "
 421                                             "only wrote %d bytes.\n",ret));
 422                         } else {
 423                                 DEB2(printk("i2c-algo-pcf.o: wrote %d bytes.\n",ret));
 424                         }
 425                 }
 426         }
 427
 428         return (i);
 429 }
 430
 431 static int algo_control(struct i2c_adapter *adapter,
 432         unsigned int cmd, unsigned long arg)
 433 {
 434         return 0;
 435 }
 436
 437 static u32 pcf_func(struct i2c_adapter *adap)
 438 {
 439         return I2C_FUNC_SMBUS_EMUL | I2C_FUNC_10BIT_ADDR |
 440                I2C_FUNC_PROTOCOL_MANGLING;
 441 }
 442
 443 /* -----exported algorithm data: -------------------------------------  */
 444
 445 static struct i2c_algorithm pcf_algo = {
 446         "PCF8584 algorithm",
 447         I2C_ALGO_PCF,
 448         pcf_xfer,
 449         NULL,
 450         NULL,                           /* slave_xmit           */
 451         NULL,                           /* slave_recv           */
 452         algo_control,                   /* ioctl                */
 453         pcf_func,                       /* functionality        */
 454 };
 455
 456 /*
 457  * registering functions to load algorithms at runtime
 458  */
 459 int i2c_pcf_add_bus(struct i2c_adapter *adap)
 460 {
 461         int i, status;
 462         struct i2c_algo_pcf_data *pcf_adap = adap->algo_data;
 463
 464         DEB2(printk("i2c-algo-pcf.o: hw routines for %s registered.\n",
 465                     adap->name));
 466
 467         /* register new adapter to i2c module... */
 468
 469         adap->id |= pcf_algo.id;
 470         adap->algo = &pcf_algo;
 471
 472         adap->timeout = 100;            /* default values, should       */
 473         adap->retries = 3;              /* be replaced by defines       */
 474
 475         if ((i = pcf_init_8584(pcf_adap))) {
 476                 return i;
 477         }
 478
 479 #ifdef MODULE
 480         MOD_INC_USE_COUNT;
 481 #endif
 482
 483         i2c_add_adapter(adap);
 484
 485         /* scan bus */
 486         if (pcf_scan) {
 487                 printk(KERN_INFO " i2c-algo-pcf.o: scanning bus %s.\n",
 488                        adap->name);
 489                 for (i = 0x00; i < 0xff; i+=2) {
 490                         if (wait_for_bb(pcf_adap)) {
 491                         printk(KERN_INFO " i2c-algo-pcf.o: scanning bus %s - TIMEOUTed.\n",
 492                            adap->name);
 493                             break;
 494                         }
 495                         i2c_outb(pcf_adap, i);
 496                         i2c_start(pcf_adap);
 497                         if ((wait_for_pin(pcf_adap, &status) >= 0) &&
 498                             ((status & I2C_PCF_LRB) == 0)) {
 499                                 printk("(%02x)",i>>1);
 500                         } else {
 501                                 printk(".");
 502                         }
 503                         i2c_stop(pcf_adap);
 504                         udelay(pcf_adap->udelay);
 505                 }
 506                 printk("\n");
 507         }
 508         return 0;
 509 }
 510
 511
 512 int i2c_pcf_del_bus(struct i2c_adapter *adap)
 513 {
 514         int res;
 515         if ((res = i2c_del_adapter(adap)) < 0)
 516                 return res;
 517         DEB2(printk("i2c-algo-pcf.o: adapter unregistered: %s\n",adap->name));
 518
 519 #ifdef MODULE
 520         MOD_DEC_USE_COUNT;
 521 #endif
 522         return 0;
 523 }
 524
 525 int __init i2c_algo_pcf_init (void)
 526 {
 527         printk("i2c-algo-pcf.o: i2c pcf8584 algorithm module\n");
 528         return 0;
 529 }
 530
 531
 532 EXPORT_SYMBOL(i2c_pcf_add_bus);
 533 EXPORT_SYMBOL(i2c_pcf_del_bus);
 534
 535 #ifdef MODULE
 536 MODULE_AUTHOR("Hans Berglund <hb@spacetec.no>");
 537 MODULE_DESCRIPTION("I2C-Bus PCF8584 algorithm");
 538 MODULE_LICENSE("GPL");
 539
 540 MODULE_PARM(pcf_scan, "i");
 541 MODULE_PARM(i2c_debug,"i");
 542
 543 MODULE_PARM_DESC(pcf_scan, "Scan for active chips on the bus");
 544 MODULE_PARM_DESC(i2c_debug,
 545         "debug level - 0 off; 1 normal; 2,3 more verbose; 9 pcf-protocol");
 546
 547
 548 int init_module(void)
 549 {
 550         return i2c_algo_pcf_init();
 551 }
 552
 553 void cleanup_module(void)
 554 {
 555 }
 556 #endif