drivers/i2c/busses/i2c-pxa.c

   1 /*
   2  *  i2c_adap_pxa.c
   3  *
   4  *  I2C adapter for the PXA I2C bus access.
   5  *
   6  *  Copyright (C) 2002 Intrinsyc Software Inc.
   7  *  Copyright (C) 2004-2005 Deep Blue Solutions Ltd.
   8  *
   9  *  This program is free software; you can redistribute it and/or modify
  10  *  it under the terms of the GNU General Public License version 2 as
  11  *  published by the Free Software Foundation.
  12  *
  13  *  History:
  14  *    Apr 2002: Initial version [CS]
  15  *    Jun 2002: Properly seperated algo/adap [FB]
  16  *    Jan 2003: Fixed several bugs concerning interrupt handling [Kai-Uwe Bloem]
  17  *    Jan 2003: added limited signal handling [Kai-Uwe Bloem]
  18  *    Sep 2004: Major rework to ensure efficient bus handling [RMK]
  19  *    Dec 2004: Added support for PXA27x and slave device probing [Liam Girdwood]
  20  *    Feb 2005: Rework slave mode handling [RMK]
  21  */
  22 #include <linux/kernel.h>
  23 #include <linux/module.h>
  24 #include <linux/i2c.h>
  25 #include <linux/i2c-id.h>
  26 #include <linux/init.h>
  27 #include <linux/time.h>
  28 #include <linux/sched.h>
  29 #include <linux/delay.h>
  30 #include <linux/errno.h>
  31 #include <linux/interrupt.h>
  32 #include <linux/i2c-pxa.h>
  33 #include <linux/platform_device.h>
  34
  35 #include <asm/hardware.h>
  36 #include <asm/irq.h>
  37 #include <asm/arch/i2c.h>
  38 #include <asm/arch/pxa-regs.h>
  39
  40 struct pxa_i2c {
  41         spinlock_t              lock;
  42         wait_queue_head_t       wait;
  43         struct i2c_msg          *msg;
  44         unsigned int            msg_num;
  45         unsigned int            msg_idx;
  46         unsigned int            msg_ptr;
  47         unsigned int            slave_addr;
  48
  49         struct i2c_adapter      adap;
  50 #ifdef CONFIG_I2C_PXA_SLAVE
  51         struct i2c_slave_client *slave;
  52 #endif
  53
  54         unsigned int            irqlogidx;
  55         u32                     isrlog[32];
  56         u32                     icrlog[32];
  57 };
  58
  59 /*
  60  * I2C Slave mode address
  61  */
  62 #define I2C_PXA_SLAVE_ADDR      0x1
  63
  64 #ifdef DEBUG
  65
  66 struct bits {
  67         u32     mask;
  68         const char *set;
  69         const char *unset;
  70 };
  71 #define BIT(m, s, u)    { .mask = m, .set = s, .unset = u }
  72
  73 static inline void
  74 decode_bits(const char *prefix, const struct bits *bits, int num, u32 val)
  75 {
  76         printk("%s %08x: ", prefix, val);
  77         while (num--) {
  78                 const char *str = val & bits->mask ? bits->set : bits->unset;
  79                 if (str)
  80                         printk("%s ", str);
  81                 bits++;
  82         }
  83 }
  84
  85 static const struct bits isr_bits[] = {
  86         BIT(ISR_RWM,    "RX",           "TX"),
  87         BIT(ISR_ACKNAK, "NAK",          "ACK"),
  88         BIT(ISR_UB,     "Bsy",          "Rdy"),
  89         BIT(ISR_IBB,    "BusBsy",       "BusRdy"),
  90         BIT(ISR_SSD,    "SlaveStop",    NULL),
  91         BIT(ISR_ALD,    "ALD",          NULL),
  92         BIT(ISR_ITE,    "TxEmpty",      NULL),
  93         BIT(ISR_IRF,    "RxFull",       NULL),
  94         BIT(ISR_GCAD,   "GenCall",      NULL),
  95         BIT(ISR_SAD,    "SlaveAddr",    NULL),
  96         BIT(ISR_BED,    "BusErr",       NULL),
  97 };
  98
  99 static void decode_ISR(unsigned int val)
 100 {
 101         decode_bits(KERN_DEBUG "ISR", isr_bits, ARRAY_SIZE(isr_bits), val);
 102         printk("\n");
 103 }
 104
 105 static const struct bits icr_bits[] = {
 106         BIT(ICR_START,  "START",        NULL),
 107         BIT(ICR_STOP,   "STOP",         NULL),
 108         BIT(ICR_ACKNAK, "ACKNAK",       NULL),
 109         BIT(ICR_TB,     "TB",           NULL),
 110         BIT(ICR_MA,     "MA",           NULL),
 111         BIT(ICR_SCLE,   "SCLE",         "scle"),
 112         BIT(ICR_IUE,    "IUE",          "iue"),
 113         BIT(ICR_GCD,    "GCD",          NULL),
 114         BIT(ICR_ITEIE,  "ITEIE",        NULL),
 115         BIT(ICR_IRFIE,  "IRFIE",        NULL),
 116         BIT(ICR_BEIE,   "BEIE",         NULL),
 117         BIT(ICR_SSDIE,  "SSDIE",        NULL),
 118         BIT(ICR_ALDIE,  "ALDIE",        NULL),
 119         BIT(ICR_SADIE,  "SADIE",        NULL),
 120         BIT(ICR_UR,     "UR",           "ur"),
 121 };
 122
 123 static void decode_ICR(unsigned int val)
 124 {
 125         decode_bits(KERN_DEBUG "ICR", icr_bits, ARRAY_SIZE(icr_bits), val);
 126         printk("\n");
 127 }
 128
 129 static unsigned int i2c_debug = DEBUG;
 130
 131 static void i2c_pxa_show_state(struct pxa_i2c *i2c, int lno, const char *fname)
 132 {
 133         dev_dbg(&i2c->adap.dev, "state:%s:%d: ISR=%08x, ICR=%08x, IBMR=%02x\n", fname, lno, ISR, ICR, IBMR);
 134 }
 135
 136 #define show_state(i2c) i2c_pxa_show_state(i2c, __LINE__, __FUNCTION__)
 137 #else
 138 #define i2c_debug       0
 139
 140 #define show_state(i2c) do { } while (0)
 141 #define decode_ISR(val) do { } while (0)
 142 #define decode_ICR(val) do { } while (0)
 143 #endif
 144
 145 #define eedbg(lvl, x...) do { if ((lvl) < 1) { printk(KERN_DEBUG "" x); } } while(0)
 146
 147 static void i2c_pxa_master_complete(struct pxa_i2c *i2c, int ret);
 148
 149 static void i2c_pxa_scream_blue_murder(struct pxa_i2c *i2c, const char *why)
 150 {
 151         unsigned int i;
 152         printk("i2c: error: %s\n", why);
 153         printk("i2c: msg_num: %d msg_idx: %d msg_ptr: %d\n",
 154                 i2c->msg_num, i2c->msg_idx, i2c->msg_ptr);
 155         printk("i2c: ICR: %08x ISR: %08x\n"
 156                "i2c: log: ", ICR, ISR);
 157         for (i = 0; i < i2c->irqlogidx; i++)
 158                 printk("[%08x:%08x] ", i2c->isrlog[i], i2c->icrlog[i]);
 159         printk("\n");
 160 }
 161
 162 static inline int i2c_pxa_is_slavemode(struct pxa_i2c *i2c)
 163 {
 164         return !(ICR & ICR_SCLE);
 165 }
 166
 167 static void i2c_pxa_abort(struct pxa_i2c *i2c)
 168 {
 169         unsigned long timeout = jiffies + HZ/4;
 170
 171         if (i2c_pxa_is_slavemode(i2c)) {
 172                 dev_dbg(&i2c->adap.dev, "%s: called in slave mode\n", __func__);
 173                 return;
 174         }
 175
 176         while (time_before(jiffies, timeout) && (IBMR & 0x1) == 0) {
 177                 unsigned long icr = ICR;
 178
 179                 icr &= ~ICR_START;
 180                 icr |= ICR_ACKNAK | ICR_STOP | ICR_TB;
 181
 182                 ICR = icr;
 183
 184                 show_state(i2c);
 185
 186                 msleep(1);
 187         }
 188
 189         ICR &= ~(ICR_MA | ICR_START | ICR_STOP);
 190 }
 191
 192 static int i2c_pxa_wait_bus_not_busy(struct pxa_i2c *i2c)
 193 {
 194         int timeout = DEF_TIMEOUT;
 195
 196         while (timeout-- && ISR & (ISR_IBB | ISR_UB)) {
 197                 if ((ISR & ISR_SAD) != 0)
 198                         timeout += 4;
 199
 200                 msleep(2);
 201                 show_state(i2c);
 202         }
 203
 204         if (timeout <= 0)
 205                 show_state(i2c);
 206
 207         return timeout <= 0 ? I2C_RETRY : 0;
 208 }
 209
 210 static int i2c_pxa_wait_master(struct pxa_i2c *i2c)
 211 {
 212         unsigned long timeout = jiffies + HZ*4;
 213
 214         while (time_before(jiffies, timeout)) {
 215                 if (i2c_debug > 1)
 216                         dev_dbg(&i2c->adap.dev, "%s: %ld: ISR=%08x, ICR=%08x, IBMR=%02x\n",
 217                                 __func__, (long)jiffies, ISR, ICR, IBMR);
 218
 219                 if (ISR & ISR_SAD) {
 220                         if (i2c_debug > 0)
 221                                 dev_dbg(&i2c->adap.dev, "%s: Slave detected\n", __func__);
 222                         goto out;
 223                 }
 224
 225                 /* wait for unit and bus being not busy, and we also do a
 226                  * quick check of the i2c lines themselves to ensure they've
 227                  * gone high...
 228                  */
 229                 if ((ISR & (ISR_UB | ISR_IBB)) == 0 && IBMR == 3) {
 230                         if (i2c_debug > 0)
 231                                 dev_dbg(&i2c->adap.dev, "%s: done\n", __func__);
 232                         return 1;
 233                 }
 234
 235                 msleep(1);
 236         }
 237
 238         if (i2c_debug > 0)
 239                 dev_dbg(&i2c->adap.dev, "%s: did not free\n", __func__);
 240  out:
 241         return 0;
 242 }
 243
 244 static int i2c_pxa_set_master(struct pxa_i2c *i2c)
 245 {
 246         if (i2c_debug)
 247                 dev_dbg(&i2c->adap.dev, "setting to bus master\n");
 248
 249         if ((ISR & (ISR_UB | ISR_IBB)) != 0) {
 250                 dev_dbg(&i2c->adap.dev, "%s: unit is busy\n", __func__);
 251                 if (!i2c_pxa_wait_master(i2c)) {
 252                         dev_dbg(&i2c->adap.dev, "%s: error: unit busy\n", __func__);
 253                         return I2C_RETRY;
 254                 }
 255         }
 256
 257         ICR |= ICR_SCLE;
 258         return 0;
 259 }
 260
 261 #ifdef CONFIG_I2C_PXA_SLAVE
 262 static int i2c_pxa_wait_slave(struct pxa_i2c *i2c)
 263 {
 264         unsigned long timeout = jiffies + HZ*1;
 265
 266         /* wait for stop */
 267
 268         show_state(i2c);
 269
 270         while (time_before(jiffies, timeout)) {
 271                 if (i2c_debug > 1)
 272                         dev_dbg(&i2c->adap.dev, "%s: %ld: ISR=%08x, ICR=%08x, IBMR=%02x\n",
 273                                 __func__, (long)jiffies, ISR, ICR, IBMR);
 274
 275                 if ((ISR & (ISR_UB|ISR_IBB|ISR_SAD)) == ISR_SAD ||
 276                     (ICR & ICR_SCLE) == 0) {
 277                         if (i2c_debug > 1)
 278                                 dev_dbg(&i2c->adap.dev, "%s: done\n", __func__);
 279                         return 1;
 280                 }
 281
 282                 msleep(1);
 283         }
 284
 285         if (i2c_debug > 0)
 286                 dev_dbg(&i2c->adap.dev, "%s: did not free\n", __func__);
 287         return 0;
 288 }
 289
 290 /*
 291  * clear the hold on the bus, and take of anything else
 292  * that has been configured
 293  */
 294 static void i2c_pxa_set_slave(struct pxa_i2c *i2c, int errcode)
 295 {
 296         show_state(i2c);
 297
 298         if (errcode < 0) {
 299                 udelay(100);   /* simple delay */
 300         } else {
 301                 /* we need to wait for the stop condition to end */
 302
 303                 /* if we where in stop, then clear... */
 304                 if (ICR & ICR_STOP) {
 305                         udelay(100);
 306                         ICR &= ~ICR_STOP;
 307                 }
 308
 309                 if (!i2c_pxa_wait_slave(i2c)) {
 310                         dev_err(&i2c->adap.dev, "%s: wait timedout\n",
 311                                 __func__);
 312                         return;
 313                 }
 314         }
 315
 316         ICR &= ~(ICR_STOP|ICR_ACKNAK|ICR_MA);
 317         ICR &= ~ICR_SCLE;
 318
 319         if (i2c_debug) {
 320                 dev_dbg(&i2c->adap.dev, "ICR now %08x, ISR %08x\n", ICR, ISR);
 321                 decode_ICR(ICR);
 322         }
 323 }
 324 #else
 325 #define i2c_pxa_set_slave(i2c, err)     do { } while (0)
 326 #endif
 327
 328 static void i2c_pxa_reset(struct pxa_i2c *i2c)
 329 {
 330         pr_debug("Resetting I2C Controller Unit\n");
 331
 332         /* abort any transfer currently under way */
 333         i2c_pxa_abort(i2c);
 334
 335         /* reset according to 9.8 */
 336         ICR = ICR_UR;
 337         ISR = I2C_ISR_INIT;
 338         ICR &= ~ICR_UR;
 339
 340         ISAR = i2c->slave_addr;
 341
 342         /* set control register values */
 343         ICR = I2C_ICR_INIT;
 344
 345 #ifdef CONFIG_I2C_PXA_SLAVE
 346         dev_info(&i2c->adap.dev, "Enabling slave mode\n");
 347         ICR |= ICR_SADIE | ICR_ALDIE | ICR_SSDIE;
 348 #endif
 349
 350         i2c_pxa_set_slave(i2c, 0);
 351
 352         /* enable unit */
 353         ICR |= ICR_IUE;
 354         udelay(100);
 355 }
 356
 357
 358 #ifdef CONFIG_I2C_PXA_SLAVE
 359 /*
 360  * I2C EEPROM emulation.
 361  */
 362 static struct i2c_eeprom_emu eeprom = {
 363         .size = I2C_EEPROM_EMU_SIZE,
 364         .watch = LIST_HEAD_INIT(eeprom.watch),
 365 };
 366
 367 struct i2c_eeprom_emu *i2c_pxa_get_eeprom(void)
 368 {
 369         return &eeprom;
 370 }
 371
 372 int i2c_eeprom_emu_addwatcher(struct i2c_eeprom_emu *emu, void *data,
 373                               unsigned int addr, unsigned int size,
 374                               struct i2c_eeprom_emu_watcher *watcher)
 375 {
 376         struct i2c_eeprom_emu_watch *watch;
 377         unsigned long flags;
 378
 379         if (addr + size > emu->size)
 380                 return -EINVAL;
 381
 382         watch = kmalloc(sizeof(struct i2c_eeprom_emu_watch), GFP_KERNEL);
 383         if (watch) {
 384                 watch->start = addr;
 385                 watch->end = addr + size - 1;
 386                 watch->ops = watcher;
 387                 watch->data = data;
 388
 389                 local_irq_save(flags);
 390                 list_add(&watch->node, &emu->watch);
 391                 local_irq_restore(flags);
 392         }
 393
 394         return watch ? 0 : -ENOMEM;
 395 }
 396
 397 void i2c_eeprom_emu_delwatcher(struct i2c_eeprom_emu *emu, void *data,
 398                                struct i2c_eeprom_emu_watcher *watcher)
 399 {
 400         struct i2c_eeprom_emu_watch *watch, *n;
 401         unsigned long flags;
 402
 403         list_for_each_entry_safe(watch, n, &emu->watch, node) {
 404                 if (watch->ops == watcher && watch->data == data) {
 405                         local_irq_save(flags);
 406                         list_del(&watch->node);
 407                         local_irq_restore(flags);
 408                         kfree(watch);
 409                 }
 410         }
 411 }
 412
 413 static void i2c_eeprom_emu_event(void *ptr, i2c_slave_event_t event)
 414 {
 415         struct i2c_eeprom_emu *emu = ptr;
 416
 417         eedbg(3, "i2c_eeprom_emu_event: %d\n", event);
 418
 419         switch (event) {
 420         case I2C_SLAVE_EVENT_START_WRITE:
 421                 emu->seen_start = 1;
 422                 eedbg(2, "i2c_eeprom: write initiated\n");
 423                 break;
 424
 425         case I2C_SLAVE_EVENT_START_READ:
 426                 emu->seen_start = 0;
 427                 eedbg(2, "i2c_eeprom: read initiated\n");
 428                 break;
 429
 430         case I2C_SLAVE_EVENT_STOP:
 431                 emu->seen_start = 0;
 432                 eedbg(2, "i2c_eeprom: received stop\n");
 433                 break;
 434
 435         default:
 436                 eedbg(0, "i2c_eeprom: unhandled event\n");
 437                 break;
 438         }
 439 }
 440
 441 static int i2c_eeprom_emu_read(void *ptr)
 442 {
 443         struct i2c_eeprom_emu *emu = ptr;
 444         int ret;
 445
 446         ret = emu->bytes[emu->ptr];
 447         emu->ptr = (emu->ptr + 1) % emu->size;
 448
 449         return ret;
 450 }
 451
 452 static void i2c_eeprom_emu_write(void *ptr, unsigned int val)
 453 {
 454         struct i2c_eeprom_emu *emu = ptr;
 455         struct i2c_eeprom_emu_watch *watch;
 456
 457         if (emu->seen_start != 0) {
 458                 eedbg(2, "i2c_eeprom_emu_write: setting ptr %02x\n", val);
 459                 emu->ptr = val;
 460                 emu->seen_start = 0;
 461                 return;
 462         }
 463
 464         emu->bytes[emu->ptr] = val;
 465
 466         eedbg(1, "i2c_eeprom_emu_write: ptr=0x%02x, val=0x%02x\n",
 467               emu->ptr, val);
 468
 469         list_for_each_entry(watch, &emu->watch, node) {
 470                 if (!watch->ops || !watch->ops->write)
 471                         continue;
 472                 if (watch->start <= emu->ptr && watch->end >= emu->ptr)
 473                         watch->ops->write(watch->data, emu->ptr, val);
 474         }
 475
 476         emu->ptr = (emu->ptr + 1) % emu->size;
 477 }
 478
 479 struct i2c_slave_client eeprom_client = {
 480         .data   = &eeprom,
 481         .event  = i2c_eeprom_emu_event,
 482         .read   = i2c_eeprom_emu_read,
 483         .write  = i2c_eeprom_emu_write
 484 };
 485
 486 /*
 487  * PXA I2C Slave mode
 488  */
 489
 490 static void i2c_pxa_slave_txempty(struct pxa_i2c *i2c, u32 isr)
 491 {
 492         if (isr & ISR_BED) {
 493                 /* what should we do here? */
 494         } else {
 495                 int ret = i2c->slave->read(i2c->slave->data);
 496
 497                 IDBR = ret;
 498                 ICR |= ICR_TB;   /* allow next byte */
 499         }
 500 }
 501
 502 static void i2c_pxa_slave_rxfull(struct pxa_i2c *i2c, u32 isr)
 503 {
 504         unsigned int byte = IDBR;
 505
 506         if (i2c->slave != NULL)
 507                 i2c->slave->write(i2c->slave->data, byte);
 508
 509         ICR |= ICR_TB;
 510 }
 511
 512 static void i2c_pxa_slave_start(struct pxa_i2c *i2c, u32 isr)
 513 {
 514         int timeout;
 515
 516         if (i2c_debug > 0)
 517                 dev_dbg(&i2c->adap.dev, "SAD, mode is slave-%cx\n",
 518                        (isr & ISR_RWM) ? 'r' : 't');
 519
 520         if (i2c->slave != NULL)
 521                 i2c->slave->event(i2c->slave->data,
 522                                  (isr & ISR_RWM) ? I2C_SLAVE_EVENT_START_READ : I2C_SLAVE_EVENT_START_WRITE);
 523
 524         /*
 525          * slave could interrupt in the middle of us generating a
 526          * start condition... if this happens, we'd better back off
 527          * and stop holding the poor thing up
 528          */
 529         ICR &= ~(ICR_START|ICR_STOP);
 530         ICR |= ICR_TB;
 531
 532         timeout = 0x10000;
 533
 534         while (1) {
 535                 if ((IBMR & 2) == 2)
 536                         break;
 537
 538                 timeout--;
 539
 540                 if (timeout <= 0) {
 541                         dev_err(&i2c->adap.dev, "timeout waiting for SCL high\n");
 542                         break;
 543                 }
 544         }
 545
 546         ICR &= ~ICR_SCLE;
 547 }
 548
 549 static void i2c_pxa_slave_stop(struct pxa_i2c *i2c)
 550 {
 551         if (i2c_debug > 2)
 552                 dev_dbg(&i2c->adap.dev, "ISR: SSD (Slave Stop)\n");
 553
 554         if (i2c->slave != NULL)
 555                 i2c->slave->event(i2c->slave->data, I2C_SLAVE_EVENT_STOP);
 556
 557         if (i2c_debug > 2)
 558                 dev_dbg(&i2c->adap.dev, "ISR: SSD (Slave Stop) acked\n");
 559
 560         /*
 561          * If we have a master-mode message waiting,
 562          * kick it off now that the slave has completed.
 563          */
 564         if (i2c->msg)
 565                 i2c_pxa_master_complete(i2c, I2C_RETRY);
 566 }
 567 #else
 568 static void i2c_pxa_slave_txempty(struct pxa_i2c *i2c, u32 isr)
 569 {
 570         if (isr & ISR_BED) {
 571                 /* what should we do here? */
 572         } else {
 573                 IDBR = 0;
 574                 ICR |= ICR_TB;
 575         }
 576 }
 577
 578 static void i2c_pxa_slave_rxfull(struct pxa_i2c *i2c, u32 isr)
 579 {
 580         ICR |= ICR_TB | ICR_ACKNAK;
 581 }
 582
 583 static void i2c_pxa_slave_start(struct pxa_i2c *i2c, u32 isr)
 584 {
 585         int timeout;
 586
 587         /*
 588          * slave could interrupt in the middle of us generating a
 589          * start condition... if this happens, we'd better back off
 590          * and stop holding the poor thing up
 591          */
 592         ICR &= ~(ICR_START|ICR_STOP);
 593         ICR |= ICR_TB | ICR_ACKNAK;
 594
 595         timeout = 0x10000;
 596
 597         while (1) {
 598                 if ((IBMR & 2) == 2)
 599                         break;
 600
 601                 timeout--;
 602
 603                 if (timeout <= 0) {
 604                         dev_err(&i2c->adap.dev, "timeout waiting for SCL high\n");
 605                         break;
 606                 }
 607         }
 608
 609         ICR &= ~ICR_SCLE;
 610 }
 611
 612 static void i2c_pxa_slave_stop(struct pxa_i2c *i2c)
 613 {
 614         if (i2c->msg)
 615                 i2c_pxa_master_complete(i2c, I2C_RETRY);
 616 }
 617 #endif
 618
 619 /*
 620  * PXA I2C Master mode
 621  */
 622
 623 static inline unsigned int i2c_pxa_addr_byte(struct i2c_msg *msg)
 624 {
 625         unsigned int addr = (msg->addr & 0x7f) << 1;
 626
 627         if (msg->flags & I2C_M_RD)
 628                 addr |= 1;
 629
 630         return addr;
 631 }
 632
 633 static inline void i2c_pxa_start_message(struct pxa_i2c *i2c)
 634 {
 635         u32 icr;
 636
 637         /*
 638          * Step 1: target slave address into IDBR
 639          */
 640         IDBR = i2c_pxa_addr_byte(i2c->msg);
 641
 642         /*
 643          * Step 2: initiate the write.
 644          */
 645         icr = ICR & ~(ICR_STOP | ICR_ALDIE);
 646         ICR = icr | ICR_START | ICR_TB;
 647 }
 648
 649 /*
 650  * We are protected by the adapter bus mutex.
 651  */
 652 static int i2c_pxa_do_xfer(struct pxa_i2c *i2c, struct i2c_msg *msg, int num)
 653 {
 654         long timeout;
 655         int ret;
 656
 657         /*
 658          * Wait for the bus to become free.
 659          */
 660         ret = i2c_pxa_wait_bus_not_busy(i2c);
 661         if (ret) {
 662                 dev_err(&i2c->adap.dev, "i2c_pxa: timeout waiting for bus free\n");
 663                 goto out;
 664         }
 665
 666         /*
 667          * Set master mode.
 668          */
 669         ret = i2c_pxa_set_master(i2c);
 670         if (ret) {
 671                 dev_err(&i2c->adap.dev, "i2c_pxa_set_master: error %d\n", ret);
 672                 goto out;
 673         }
 674
 675         spin_lock_irq(&i2c->lock);
 676
 677         i2c->msg = msg;
 678         i2c->msg_num = num;
 679         i2c->msg_idx = 0;
 680         i2c->msg_ptr = 0;
 681         i2c->irqlogidx = 0;
 682
 683         i2c_pxa_start_message(i2c);
 684
 685         spin_unlock_irq(&i2c->lock);
 686
 687         /*
 688          * The rest of the processing occurs in the interrupt handler.
 689          */
 690         timeout = wait_event_timeout(i2c->wait, i2c->msg_num == 0, HZ * 5);
 691
 692         /*
 693          * We place the return code in i2c->msg_idx.
 694          */
 695         ret = i2c->msg_idx;
 696
 697         if (timeout == 0)
 698                 i2c_pxa_scream_blue_murder(i2c, "timeout");
 699
 700  out:
 701         return ret;
 702 }
 703
 704 /*
 705  * i2c_pxa_master_complete - complete the message and wake up.
 706  */
 707 static void i2c_pxa_master_complete(struct pxa_i2c *i2c, int ret)
 708 {
 709         i2c->msg_ptr = 0;
 710         i2c->msg = NULL;
 711         i2c->msg_idx ++;
 712         i2c->msg_num = 0;
 713         if (ret)
 714                 i2c->msg_idx = ret;
 715         wake_up(&i2c->wait);
 716 }
 717
 718 static void i2c_pxa_irq_txempty(struct pxa_i2c *i2c, u32 isr)
 719 {
 720         u32 icr = ICR & ~(ICR_START|ICR_STOP|ICR_ACKNAK|ICR_TB);
 721
 722  again:
 723         /*
 724          * If ISR_ALD is set, we lost arbitration.
 725          */
 726         if (isr & ISR_ALD) {
 727                 /*
 728                  * Do we need to do anything here?  The PXA docs
 729                  * are vague about what happens.
 730                  */
 731                 i2c_pxa_scream_blue_murder(i2c, "ALD set");
 732
 733                 /*
 734                  * We ignore this error.  We seem to see spurious ALDs
 735                  * for seemingly no reason.  If we handle them as I think
 736                  * they should, we end up causing an I2C error, which
 737                  * is painful for some systems.
 738                  */
 739                 return; /* ignore */
 740         }
 741
 742         if (isr & ISR_BED) {
 743                 int ret = BUS_ERROR;
 744
 745                 /*
 746                  * I2C bus error - either the device NAK'd us, or
 747                  * something more serious happened.  If we were NAK'd
 748                  * on the initial address phase, we can retry.
 749                  */
 750                 if (isr & ISR_ACKNAK) {
 751                         if (i2c->msg_ptr == 0 && i2c->msg_idx == 0)
 752                                 ret = I2C_RETRY;
 753                         else
 754                                 ret = XFER_NAKED;
 755                 }
 756                 i2c_pxa_master_complete(i2c, ret);
 757         } else if (isr & ISR_RWM) {
 758                 /*
 759                  * Read mode.  We have just sent the address byte, and
 760                  * now we must initiate the transfer.
 761                  */
 762                 if (i2c->msg_ptr == i2c->msg->len - 1 &&
 763                     i2c->msg_idx == i2c->msg_num - 1)
 764                         icr |= ICR_STOP | ICR_ACKNAK;
 765
 766                 icr |= ICR_ALDIE | ICR_TB;
 767         } else if (i2c->msg_ptr < i2c->msg->len) {
 768                 /*
 769                  * Write mode.  Write the next data byte.
 770                  */
 771                 IDBR = i2c->msg->buf[i2c->msg_ptr++];
 772
 773                 icr |= ICR_ALDIE | ICR_TB;
 774
 775                 /*
 776                  * If this is the last byte of the last message, send
 777                  * a STOP.
 778                  */
 779                 if (i2c->msg_ptr == i2c->msg->len &&
 780                     i2c->msg_idx == i2c->msg_num - 1)
 781                         icr |= ICR_STOP;
 782         } else if (i2c->msg_idx < i2c->msg_num - 1) {
 783                 /*
 784                  * Next segment of the message.
 785                  */
 786                 i2c->msg_ptr = 0;
 787                 i2c->msg_idx ++;
 788                 i2c->msg++;
 789
 790                 /*
 791                  * If we aren't doing a repeated start and address,
 792                  * go back and try to send the next byte.  Note that
 793                  * we do not support switching the R/W direction here.
 794                  */
 795                 if (i2c->msg->flags & I2C_M_NOSTART)
 796                         goto again;
 797
 798                 /*
 799                  * Write the next address.
 800                  */
 801                 IDBR = i2c_pxa_addr_byte(i2c->msg);
 802
 803                 /*
 804                  * And trigger a repeated start, and send the byte.
 805                  */
 806                 icr &= ~ICR_ALDIE;
 807                 icr |= ICR_START | ICR_TB;
 808         } else {
 809                 if (i2c->msg->len == 0) {
 810                         /*
 811                          * Device probes have a message length of zero
 812                          * and need the bus to be reset before it can
 813                          * be used again.
 814                          */
 815                         i2c_pxa_reset(i2c);
 816                 }
 817                 i2c_pxa_master_complete(i2c, 0);
 818         }
 819
 820         i2c->icrlog[i2c->irqlogidx-1] = icr;
 821
 822         ICR = icr;
 823         show_state(i2c);
 824 }
 825
 826 static void i2c_pxa_irq_rxfull(struct pxa_i2c *i2c, u32 isr)
 827 {
 828         u32 icr = ICR & ~(ICR_START|ICR_STOP|ICR_ACKNAK|ICR_TB);
 829
 830         /*
 831          * Read the byte.
 832          */
 833         i2c->msg->buf[i2c->msg_ptr++] = IDBR;
 834
 835         if (i2c->msg_ptr < i2c->msg->len) {
 836                 /*
 837                  * If this is the last byte of the last
 838                  * message, send a STOP.
 839                  */
 840                 if (i2c->msg_ptr == i2c->msg->len - 1)
 841                         icr |= ICR_STOP | ICR_ACKNAK;
 842
 843                 icr |= ICR_ALDIE | ICR_TB;
 844         } else {
 845                 i2c_pxa_master_complete(i2c, 0);
 846         }
 847
 848         i2c->icrlog[i2c->irqlogidx-1] = icr;
 849
 850         ICR = icr;
 851 }
 852
 853 static irqreturn_t i2c_pxa_handler(int this_irq, void *dev_id, struct pt_regs *regs)
 854 {
 855         struct pxa_i2c *i2c = dev_id;
 856         u32 isr = ISR;
 857
 858         if (i2c_debug > 2 && 0) {
 859                 dev_dbg(&i2c->adap.dev, "%s: ISR=%08x, ICR=%08x, IBMR=%02x\n",
 860                         __func__, isr, ICR, IBMR);
 861                 decode_ISR(isr);
 862         }
 863
 864         if (i2c->irqlogidx < ARRAY_SIZE(i2c->isrlog))
 865                 i2c->isrlog[i2c->irqlogidx++] = isr;
 866
 867         show_state(i2c);
 868
 869         /*
 870          * Always clear all pending IRQs.
 871          */
 872         ISR = isr & (ISR_SSD|ISR_ALD|ISR_ITE|ISR_IRF|ISR_SAD|ISR_BED);
 873
 874         if (isr & ISR_SAD)
 875                 i2c_pxa_slave_start(i2c, isr);
 876         if (isr & ISR_SSD)
 877                 i2c_pxa_slave_stop(i2c);
 878
 879         if (i2c_pxa_is_slavemode(i2c)) {
 880                 if (isr & ISR_ITE)
 881                         i2c_pxa_slave_txempty(i2c, isr);
 882                 if (isr & ISR_IRF)
 883                         i2c_pxa_slave_rxfull(i2c, isr);
 884         } else if (i2c->msg) {
 885                 if (isr & ISR_ITE)
 886                         i2c_pxa_irq_txempty(i2c, isr);
 887                 if (isr & ISR_IRF)
 888                         i2c_pxa_irq_rxfull(i2c, isr);
 889         } else {
 890                 i2c_pxa_scream_blue_murder(i2c, "spurious irq");
 891         }
 892
 893         return IRQ_HANDLED;
 894 }
 895
 896
 897 static int i2c_pxa_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
 898 {
 899         struct pxa_i2c *i2c = adap->algo_data;
 900         int ret, i;
 901
 902         /* If the I2C controller is disabled we need to reset it (probably due
 903            to a suspend/resume destroying state). We do this here as we can then
 904            avoid worrying about resuming the controller before its users. */
 905         if (!(ICR & ICR_IUE))
 906                 i2c_pxa_reset(i2c);
 907
 908         for (i = adap->retries; i >= 0; i--) {
 909                 ret = i2c_pxa_do_xfer(i2c, msgs, num);
 910                 if (ret != I2C_RETRY)
 911                         goto out;
 912
 913                 if (i2c_debug)
 914                         dev_dbg(&adap->dev, "Retrying transmission\n");
 915                 udelay(100);
 916         }
 917         i2c_pxa_scream_blue_murder(i2c, "exhausted retries");
 918         ret = -EREMOTEIO;
 919  out:
 920         i2c_pxa_set_slave(i2c, ret);
 921         return ret;
 922 }
 923
 924 static u32 i2c_pxa_functionality(struct i2c_adapter *adap)
 925 {
 926         return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
 927 }
 928
 929 static struct i2c_algorithm i2c_pxa_algorithm = {
 930         .master_xfer    = i2c_pxa_xfer,
 931         .functionality  = i2c_pxa_functionality,
 932 };
 933
 934 static struct pxa_i2c i2c_pxa = {
 935         .lock   = SPIN_LOCK_UNLOCKED,
 936         .wait   = __WAIT_QUEUE_HEAD_INITIALIZER(i2c_pxa.wait),
 937         .adap   = {
 938                 .owner          = THIS_MODULE,
 939                 .algo           = &i2c_pxa_algorithm,
 940                 .name           = "pxa2xx-i2c",
 941                 .retries        = 5,
 942         },
 943 };
 944
 945 static int i2c_pxa_probe(struct platform_device *dev)
 946 {
 947         struct pxa_i2c *i2c = &i2c_pxa;
 948 #ifdef CONFIG_I2C_PXA_SLAVE
 949         struct i2c_pxa_platform_data *plat = dev->dev.platform_data;
 950 #endif
 951         int ret;
 952
 953 #ifdef CONFIG_PXA27x
 954         pxa_gpio_mode(GPIO117_I2CSCL_MD);
 955         pxa_gpio_mode(GPIO118_I2CSDA_MD);
 956         udelay(100);
 957 #endif
 958
 959         i2c->slave_addr = I2C_PXA_SLAVE_ADDR;
 960
 961 #ifdef CONFIG_I2C_PXA_SLAVE
 962         i2c->slave = &eeprom_client;
 963         if (plat) {
 964                 i2c->slave_addr = plat->slave_addr;
 965                 if (plat->slave)
 966                         i2c->slave = plat->slave;
 967         }
 968 #endif
 969
 970         pxa_set_cken(CKEN14_I2C, 1);
 971         ret = request_irq(IRQ_I2C, i2c_pxa_handler, SA_INTERRUPT,
 972                           "pxa2xx-i2c", i2c);
 973         if (ret)
 974                 goto out;
 975
 976         i2c_pxa_reset(i2c);
 977
 978         i2c->adap.algo_data = i2c;
 979         i2c->adap.dev.parent = &dev->dev;
 980
 981         ret = i2c_add_adapter(&i2c->adap);
 982         if (ret < 0) {
 983                 printk(KERN_INFO "I2C: Failed to add bus\n");
 984                 goto err_irq;
 985         }
 986
 987         platform_set_drvdata(dev, i2c);
 988
 989 #ifdef CONFIG_I2C_PXA_SLAVE
 990         printk(KERN_INFO "I2C: %s: PXA I2C adapter, slave address %d\n",
 991                i2c->adap.dev.bus_id, i2c->slave_addr);
 992 #else
 993         printk(KERN_INFO "I2C: %s: PXA I2C adapter\n",
 994                i2c->adap.dev.bus_id);
 995 #endif
 996         return 0;
 997
 998  err_irq:
 999         free_irq(IRQ_I2C, i2c);
1000  out:
1001         return ret;
1002 }
1003
1004 static int i2c_pxa_remove(struct platform_device *dev)
1005 {
1006         struct pxa_i2c *i2c = platform_get_drvdata(dev);
1007
1008         platform_set_drvdata(dev, NULL);
1009
1010         i2c_del_adapter(&i2c->adap);
1011         free_irq(IRQ_I2C, i2c);
1012         pxa_set_cken(CKEN14_I2C, 0);
1013
1014         return 0;
1015 }
1016
1017 static struct platform_driver i2c_pxa_driver = {
1018         .probe          = i2c_pxa_probe,
1019         .remove         = i2c_pxa_remove,
1020         .driver         = {
1021                 .name   = "pxa2xx-i2c",
1022         },
1023 };
1024
1025 static int __init i2c_adap_pxa_init(void)
1026 {
1027         return platform_driver_register(&i2c_pxa_driver);
1028 }
1029
1030 static void i2c_adap_pxa_exit(void)
1031 {
1032         return platform_driver_unregister(&i2c_pxa_driver);
1033 }
1034
1035 MODULE_LICENSE("GPL");
1036
1037 module_init(i2c_adap_pxa_init);
1038 module_exit(i2c_adap_pxa_exit);