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