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