LXR linux-old/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 */
  52static int i2c_debug=0;
  53static 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
  66static void i2c_start(struct i2c_algo_pcf_data *adap) 
  67{
  68        DEBPROTO(printk("S "));
  69        set_pcf(adap, 1, I2C_PCF_START);
  70}
  71
  72static 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
  79static 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
  86static 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
 106static inline void pcf_sleep(unsigned long timeout)
 107{
 108        schedule_timeout( timeout * HZ);
 109}
 110
 111
 112static 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 */
 140static 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
 198static 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
 221static 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
 258static 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
 303static 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
 347static 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
 428static int algo_control(struct i2c_adapter *adapter, 
 429        unsigned int cmd, unsigned long arg)
 430{
 431        return 0;
 432}
 433
 434static 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
 442static 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 */
 456int 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        i2c_add_adapter(adap);
 481
 482        /* scan bus */
 483        if (pcf_scan) {
 484                printk(KERN_INFO " i2c-algo-pcf.o: scanning bus %s.\n",
 485                       adap->name);
 486                for (i = 0x00; i < 0xff; i+=2) {
 487                        if (wait_for_bb(pcf_adap)) {
 488                        printk(KERN_INFO " i2c-algo-pcf.o: scanning bus %s - TIMEOUTed.\n",
 489                           adap->name);
 490                            break;
 491                        }
 492                        i2c_outb(pcf_adap, i);
 493                        i2c_start(pcf_adap);
 494                        if ((wait_for_pin(pcf_adap, &status) >= 0) && 
 495                            ((status & I2C_PCF_LRB) == 0)) { 
 496                                printk("(%02x)",i>>1); 
 497                        } else {
 498                                printk("."); 
 499                        }
 500                        i2c_stop(pcf_adap);
 501                        udelay(pcf_adap->udelay);
 502                }
 503                printk("\n");
 504        }
 505        return 0;
 506}
 507
 508
 509int i2c_pcf_del_bus(struct i2c_adapter *adap)
 510{
 511        int res;
 512        if ((res = i2c_del_adapter(adap)) < 0)
 513                return res;
 514        DEB2(printk("i2c-algo-pcf.o: adapter unregistered: %s\n",adap->name));
 515
 516#ifdef MODULE
 517        MOD_DEC_USE_COUNT;
 518#endif
 519        return 0;
 520}
 521
 522int __init i2c_algo_pcf_init (void)
 523{
 524        printk("i2c-algo-pcf.o: i2c pcf8584 algorithm module\n");
 525        return 0;
 526}
 527
 528
 529EXPORT_SYMBOL(i2c_pcf_add_bus);
 530EXPORT_SYMBOL(i2c_pcf_del_bus);
 531
 532#ifdef MODULE
 533MODULE_AUTHOR("Hans Berglund <hb@spacetec.no>");
 534MODULE_DESCRIPTION("I2C-Bus PCF8584 algorithm");
 535MODULE_LICENSE("GPL");
 536
 537MODULE_PARM(pcf_scan, "i");
 538MODULE_PARM(i2c_debug,"i");
 539
 540MODULE_PARM_DESC(pcf_scan, "Scan for active chips on the bus");
 541MODULE_PARM_DESC(i2c_debug,
 542        "debug level - 0 off; 1 normal; 2,3 more verbose; 9 pcf-protocol");
 543
 544
 545int init_module(void) 
 546{
 547        return i2c_algo_pcf_init();
 548}
 549
 550void cleanup_module(void) 
 551{
 552}
 553#endif
 554