git.oblomov.eu Git - linux-2.6/blob - 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
  34 #include <asm/hardware.h>
  35 #include <asm/irq.h>
  36 #include <asm/arch/i2c.h>
  37 #include <asm/arch/pxa-regs.h>
  38
  39 struct pxa_i2c {
  40         spinlock_t              lock;
  41         wait_queue_head_t       wait;
  42         struct i2c_msg          *msg;
  43         unsigned int            msg_num;
  44         unsigned int            msg_idx;
  45         unsigned int            msg_ptr;
  46         unsigned int            slave_addr;
  47
  48         struct i2c_adapter      adap;
  49 #ifdef CONFIG_I2C_PXA_SLAVE
  50         struct i2c_slave_client *slave;
  51 #endif
  52
  53         unsigned int            irqlogidx;
  54         u32                     isrlog[32];
  55         u32                     icrlog[32];
  56 };
  57
  58 /*
  59  * I2C Slave mode address
  60  */
  61 #define I2C_PXA_SLAVE_ADDR      0x1
  62
  63 #ifdef DEBUG
  64
  65 struct bits {
  66         u32     mask;
  67         const char *set;
  68         const char *unset;
  69 };
  70 #define BIT(m, s, u)    { .mask = m, .set = s, .unset = u }
  71
  72 static inline void
  73 decode_bits(const char *prefix, const struct bits *bits, int num, u32 val)
  74 {
  75         printk("%s %08x: ", prefix, val);
  76         while (num--) {
  77                 const char *str = val & bits->mask ? bits->set : bits->unset;
  78                 if (str)
  79                         printk("%s ", str);
  80                 bits++;
  81         }
  82 }
  83
  84 static const struct bits isr_bits[] = {
  85         BIT(ISR_RWM,    "RX",           "TX"),
  86         BIT(ISR_ACKNAK, "NAK",          "ACK"),
  87         BIT(ISR_UB,     "Bsy",          "Rdy"),
  88         BIT(ISR_IBB,    "BusBsy",       "BusRdy"),
  89         BIT(ISR_SSD,    "SlaveStop",    NULL),
  90         BIT(ISR_ALD,    "ALD",          NULL),
  91         BIT(ISR_ITE,    "TxEmpty",      NULL),
  92         BIT(ISR_IRF,    "RxFull",       NULL),
  93         BIT(ISR_GCAD,   "GenCall",      NULL),
  94         BIT(ISR_SAD,    "SlaveAddr",    NULL),
  95         BIT(ISR_BED,    "BusErr",       NULL),
  96 };
  97
  98 static void decode_ISR(unsigned int val)
  99 {
 100         decode_bits(KERN_DEBUG "ISR", isr_bits, ARRAY_SIZE(isr_bits), val);
 101         printk("\n");
 102 }
 103
 104 static const struct bits icr_bits[] = {
 105         BIT(ICR_START,  "START",        NULL),
 106         BIT(ICR_STOP,   "STOP",         NULL),
 107         BIT(ICR_ACKNAK, "ACKNAK",       NULL),
 108         BIT(ICR_TB,     "TB",           NULL),
 109         BIT(ICR_MA,     "MA",           NULL),
 110         BIT(ICR_SCLE,   "SCLE",         "scle"),
 111         BIT(ICR_IUE,    "IUE",          "iue"),
 112         BIT(ICR_GCD,    "GCD",          NULL),
 113         BIT(ICR_ITEIE,  "ITEIE",        NULL),
 114         BIT(ICR_IRFIE,  "IRFIE",        NULL),
 115         BIT(ICR_BEIE,   "BEIE",         NULL),
 116         BIT(ICR_SSDIE,  "SSDIE",        NULL),
 117         BIT(ICR_ALDIE,  "ALDIE",        NULL),
 118         BIT(ICR_SADIE,  "SADIE",        NULL),
 119         BIT(ICR_UR,     "UR",           "ur"),
 120 };
 121
 122 static void decode_ICR(unsigned int val)
 123 {
 124         decode_bits(KERN_DEBUG "ICR", icr_bits, ARRAY_SIZE(icr_bits), val);
 125         printk("\n");
 126 }
 127
 128 static unsigned int i2c_debug = DEBUG;
 129
 130 static void i2c_pxa_show_state(struct pxa_i2c *i2c, int lno, const char *fname)
 131 {
 132         dev_dbg(&i2c->adap.dev, "state:%s:%d: ISR=%08x, ICR=%08x, IBMR=%02x\n", fname, lno, ISR, ICR, IBMR);
 133 }
 134
 135 #define show_state(i2c) i2c_pxa_show_state(i2c, __LINE__, __FUNCTION__)
 136 #else
 137 #define i2c_debug       0
 138
 139 #define show_state(i2c) do { } while (0)
 140 #define decode_ISR(val) do { } while (0)
 141 #define decode_ICR(val) do { } while (0)
 142 #endif
 143
 144 #define eedbg(lvl, x...) do { if ((lvl) < 1) { printk(KERN_DEBUG "" x); } } while(0)
 145
 146 static void i2c_pxa_master_complete(struct pxa_i2c *i2c, int ret);
 147
 148 static void i2c_pxa_scream_blue_murder(struct pxa_i2c *i2c, const char *why)
 149 {
 150         unsigned int i;
 151         printk("i2c: error: %s\n", why);
 152         printk("i2c: msg_num: %d msg_idx: %d msg_ptr: %d\n",
 153                 i2c->msg_num, i2c->msg_idx, i2c->msg_ptr);
 154         printk("i2c: ICR: %08x ISR: %08x\n"
 155                "i2c: log: ", ICR, ISR);
 156         for (i = 0; i < i2c->irqlogidx; i++)
 157                 printk("[%08x:%08x] ", i2c->isrlog[i], i2c->icrlog[i]);
 158         printk("\n");
 159 }
 160
 161 static inline int i2c_pxa_is_slavemode(struct pxa_i2c *i2c)
 162 {
 163         return !(ICR & ICR_SCLE);
 164 }
 165
 166 static void i2c_pxa_abort(struct pxa_i2c *i2c)
 167 {
 168         unsigned long timeout = jiffies + HZ/4;
 169
 170         if (i2c_pxa_is_slavemode(i2c)) {
 171                 dev_dbg(&i2c->adap.dev, "%s: called in slave mode\n", __func__);
 172                 return;
 173         }
 174
 175         while (time_before(jiffies, timeout) && (IBMR & 0x1) == 0) {
 176                 unsigned long icr = ICR;
 177
 178                 icr &= ~ICR_START;
 179                 icr |= ICR_ACKNAK | ICR_STOP | ICR_TB;
 180
 181                 ICR = icr;
 182
 183                 show_state(i2c);
 184
 185                 msleep(1);
 186         }
 187
 188         ICR &= ~(ICR_MA | ICR_START | ICR_STOP);
 189 }
 190
 191 static int i2c_pxa_wait_bus_not_busy(struct pxa_i2c *i2c)
 192 {
 193         int timeout = DEF_TIMEOUT;
 194
 195         while (timeout-- && ISR & (ISR_IBB | ISR_UB)) {
 196                 if ((ISR & ISR_SAD) != 0)
 197                         timeout += 4;
 198
 199                 msleep(2);
 200                 show_state(i2c);
 201         }
 202
 203         if (timeout <= 0)
 204                 show_state(i2c);
 205
 206         return timeout <= 0 ? I2C_RETRY : 0;
 207 }
 208
 209 static int i2c_pxa_wait_master(struct pxa_i2c *i2c)
 210 {
 211         unsigned long timeout = jiffies + HZ*4;
 212
 213         while (time_before(jiffies, timeout)) {
 214                 if (i2c_debug > 1)
 215                         dev_dbg(&i2c->adap.dev, "%s: %ld: ISR=%08x, ICR=%08x, IBMR=%02x\n",
 216                                 __func__, (long)jiffies, ISR, ICR, IBMR);
 217
 218                 if (ISR & ISR_SAD) {
 219                         if (i2c_debug > 0)
 220                                 dev_dbg(&i2c->adap.dev, "%s: Slave detected\n", __func__);
 221                         goto out;
 222                 }
 223
 224                 /* wait for unit and bus being not busy, and we also do a
 225                  * quick check of the i2c lines themselves to ensure they've
 226                  * gone high...
 227                  */
 228                 if ((ISR & (ISR_UB | ISR_IBB)) == 0 && IBMR == 3) {
 229                         if (i2c_debug > 0)
 230                                 dev_dbg(&i2c->adap.dev, "%s: done\n", __func__);
 231                         return 1;
 232                 }
 233
 234                 msleep(1);
 235         }
 236
 237         if (i2c_debug > 0)
 238                 dev_dbg(&i2c->adap.dev, "%s: did not free\n", __func__);
 239  out:
 240         return 0;
 241 }
 242
 243 static int i2c_pxa_set_master(struct pxa_i2c *i2c)
 244 {
 245         if (i2c_debug)
 246                 dev_dbg(&i2c->adap.dev, "setting to bus master\n");
 247
 248         if ((ISR & (ISR_UB | ISR_IBB)) != 0) {
 249                 dev_dbg(&i2c->adap.dev, "%s: unit is busy\n", __func__);
 250                 if (!i2c_pxa_wait_master(i2c)) {
 251                         dev_dbg(&i2c->adap.dev, "%s: error: unit busy\n", __func__);
 252                         return I2C_RETRY;
 253                 }
 254         }
 255
 256         ICR |= ICR_SCLE;
 257         return 0;
 258 }
 259
 260 #ifdef CONFIG_I2C_PXA_SLAVE
 261 static int i2c_pxa_wait_slave(struct pxa_i2c *i2c)
 262 {
 263         unsigned long timeout = jiffies + HZ*1;
 264
 265         /* wait for stop */
 266
 267         show_state(i2c);
 268
 269         while (time_before(jiffies, timeout)) {
 270                 if (i2c_debug > 1)
 271                         dev_dbg(&i2c->adap.dev, "%s: %ld: ISR=%08x, ICR=%08x, IBMR=%02x\n",
 272                                 __func__, (long)jiffies, ISR, ICR, IBMR);
 273
 274                 if ((ISR & (ISR_UB|ISR_IBB|ISR_SAD)) == ISR_SAD ||
 275                     (ICR & ICR_SCLE) == 0) {
 276                         if (i2c_debug > 1)
 277                                 dev_dbg(&i2c->adap.dev, "%s: done\n", __func__);
 278                         return 1;
 279                 }
 280
 281                 msleep(1);
 282         }
 283
 284         if (i2c_debug > 0)
 285                 dev_dbg(&i2c->adap.dev, "%s: did not free\n", __func__);
 286         return 0;
 287 }
 288
 289 /*
 290  * clear the hold on the bus, and take of anything else
 291  * that has been configured
 292  */
 293 static void i2c_pxa_set_slave(struct pxa_i2c *i2c, int errcode)
 294 {
 295         show_state(i2c);
 296
 297         if (errcode < 0) {
 298                 udelay(100);   /* simple delay */
 299         } else {
 300                 /* we need to wait for the stop condition to end */
 301
 302                 /* if we where in stop, then clear... */
 303                 if (ICR & ICR_STOP) {
 304                         udelay(100);
 305                         ICR &= ~ICR_STOP;
 306                 }
 307
 308                 if (!i2c_pxa_wait_slave(i2c)) {
 309                         dev_err(&i2c->adap.dev, "%s: wait timedout\n",
 310                                 __func__);
 311                         return;
 312                 }
 313         }
 314
 315         ICR &= ~(ICR_STOP|ICR_ACKNAK|ICR_MA);
 316         ICR &= ~ICR_SCLE;
 317
 318         if (i2c_debug) {
 319                 dev_dbg(&i2c->adap.dev, "ICR now %08x, ISR %08x\n", ICR, ISR);
 320                 decode_ICR(ICR);
 321         }
 322 }
 323 #else
 324 #define i2c_pxa_set_slave(i2c, err)     do { } while (0)
 325 #endif
 326
 327 static void i2c_pxa_reset(struct pxa_i2c *i2c)
 328 {
 329         pr_debug("Resetting I2C Controller Unit\n");
 330
 331         /* abort any transfer currently under way */
 332         i2c_pxa_abort(i2c);
 333
 334         /* reset according to 9.8 */
 335         ICR = ICR_UR;
 336         ISR = I2C_ISR_INIT;
 337         ICR &= ~ICR_UR;
 338
 339         ISAR = i2c->slave_addr;
 340
 341         /* set control register values */
 342         ICR = I2C_ICR_INIT;
 343
 344 #ifdef CONFIG_I2C_PXA_SLAVE
 345         dev_info(&i2c->adap.dev, "Enabling slave mode\n");
 346         ICR |= ICR_SADIE | ICR_ALDIE | ICR_SSDIE;
 347 #endif
 348
 349         i2c_pxa_set_slave(i2c, 0);
 350
 351         /* enable unit */
 352         ICR |= ICR_IUE;
 353         udelay(100);
 354 }
 355
 356
 357 #ifdef CONFIG_I2C_PXA_SLAVE
 358 /*
 359  * I2C EEPROM emulation.
 360  */
 361 static struct i2c_eeprom_emu eeprom = {
 362         .size = I2C_EEPROM_EMU_SIZE,
 363         .watch = LIST_HEAD_INIT(eeprom.watch),
 364 };
 365
 366 struct i2c_eeprom_emu *i2c_pxa_get_eeprom(void)
 367 {
 368         return &eeprom;
 369 }
 370
 371 int i2c_eeprom_emu_addwatcher(struct i2c_eeprom_emu *emu, void *data,
 372                               unsigned int addr, unsigned int size,
 373                               struct i2c_eeprom_emu_watcher *watcher)
 374 {
 375         struct i2c_eeprom_emu_watch *watch;
 376         unsigned long flags;
 377
 378         if (addr + size > emu->size)
 379                 return -EINVAL;
 380
 381         watch = kmalloc(sizeof(struct i2c_eeprom_emu_watch), GFP_KERNEL);
 382         if (watch) {
 383                 watch->start = addr;
 384                 watch->end = addr + size - 1;
 385                 watch->ops = watcher;
 386                 watch->data = data;
 387
 388                 local_irq_save(flags);
 389                 list_add(&watch->node, &emu->watch);
 390                 local_irq_restore(flags);
 391         }
 392
 393         return watch ? 0 : -ENOMEM;
 394 }
 395
 396 void i2c_eeprom_emu_delwatcher(struct i2c_eeprom_emu *emu, void *data,
 397                                struct i2c_eeprom_emu_watcher *watcher)
 398 {
 399         struct i2c_eeprom_emu_watch *watch, *n;
 400         unsigned long flags;
 401
 402         list_for_each_entry_safe(watch, n, &emu->watch, node) {
 403                 if (watch->ops == watcher && watch->data == data) {
 404                         local_irq_save(flags);
 405                         list_del(&watch->node);
 406                         local_irq_restore(flags);
 407                         kfree(watch);
 408                 }
 409         }
 410 }
 411
 412 static void i2c_eeprom_emu_event(void *ptr, i2c_slave_event_t event)
 413 {
 414         struct i2c_eeprom_emu *emu = ptr;
 415
 416         eedbg(3, "i2c_eeprom_emu_event: %d\n", event);
 417
 418         switch (event) {
 419         case I2C_SLAVE_EVENT_START_WRITE:
 420                 emu->seen_start = 1;
 421                 eedbg(2, "i2c_eeprom: write initiated\n");
 422                 break;
 423
 424         case I2C_SLAVE_EVENT_START_READ:
 425                 emu->seen_start = 0;
 426                 eedbg(2, "i2c_eeprom: read initiated\n");
 427                 break;
 428
 429         case I2C_SLAVE_EVENT_STOP:
 430                 emu->seen_start = 0;
 431                 eedbg(2, "i2c_eeprom: received stop\n");
 432                 break;
 433
 434         default:
 435                 eedbg(0, "i2c_eeprom: unhandled event\n");
 436                 break;
 437         }
 438 }
 439
 440 static int i2c_eeprom_emu_read(void *ptr)
 441 {
 442         struct i2c_eeprom_emu *emu = ptr;
 443         int ret;
 444
 445         ret = emu->bytes[emu->ptr];
 446         emu->ptr = (emu->ptr + 1) % emu->size;
 447
 448         return ret;
 449 }
 450
 451 static void i2c_eeprom_emu_write(void *ptr, unsigned int val)
 452 {
 453         struct i2c_eeprom_emu *emu = ptr;
 454         struct i2c_eeprom_emu_watch *watch;
 455
 456         if (emu->seen_start != 0) {
 457                 eedbg(2, "i2c_eeprom_emu_write: setting ptr %02x\n", val);
 458                 emu->ptr = val;
 459                 emu->seen_start = 0;
 460                 return;
 461         }
 462
 463         emu->bytes[emu->ptr] = val;
 464
 465         eedbg(1, "i2c_eeprom_emu_write: ptr=0x%02x, val=0x%02x\n",
 466               emu->ptr, val);
 467
 468         list_for_each_entry(watch, &emu->watch, node) {
 469                 if (!watch->ops || !watch->ops->write)
 470                         continue;
 471                 if (watch->start <= emu->ptr && watch->end >= emu->ptr)
 472                         watch->ops->write(watch->data, emu->ptr, val);
 473         }
 474
 475         emu->ptr = (emu->ptr + 1) % emu->size;
 476 }
 477
 478 struct i2c_slave_client eeprom_client = {
 479         .data   = &eeprom,
 480         .event  = i2c_eeprom_emu_event,
 481         .read   = i2c_eeprom_emu_read,
 482         .write  = i2c_eeprom_emu_write
 483 };
 484
 485 /*
 486  * PXA I2C Slave mode
 487  */
 488
 489 static void i2c_pxa_slave_txempty(struct pxa_i2c *i2c, u32 isr)
 490 {
 491         if (isr & ISR_BED) {
 492                 /* what should we do here? */
 493         } else {
 494                 int ret = i2c->slave->read(i2c->slave->data);
 495
 496                 IDBR = ret;
 497                 ICR |= ICR_TB;   /* allow next byte */
 498         }
 499 }
 500
 501 static void i2c_pxa_slave_rxfull(struct pxa_i2c *i2c, u32 isr)
 502 {
 503         unsigned int byte = IDBR;
 504
 505         if (i2c->slave != NULL)
 506                 i2c->slave->write(i2c->slave->data, byte);
 507
 508         ICR |= ICR_TB;
 509 }
 510
 511 static void i2c_pxa_slave_start(struct pxa_i2c *i2c, u32 isr)
 512 {
 513         int timeout;
 514
 515         if (i2c_debug > 0)
 516                 dev_dbg(&i2c->adap.dev, "SAD, mode is slave-%cx\n",
 517                        (isr & ISR_RWM) ? 'r' : 't');
 518
 519         if (i2c->slave != NULL)
 520                 i2c->slave->event(i2c->slave->data,
 521                                  (isr & ISR_RWM) ? I2C_SLAVE_EVENT_START_READ : I2C_SLAVE_EVENT_START_WRITE);
 522
 523         /*
 524          * slave could interrupt in the middle of us generating a
 525          * start condition... if this happens, we'd better back off
 526          * and stop holding the poor thing up
 527          */
 528         ICR &= ~(ICR_START|ICR_STOP);
 529         ICR |= ICR_TB;
 530
 531         timeout = 0x10000;
 532
 533         while (1) {
 534                 if ((IBMR & 2) == 2)
 535                         break;
 536
 537                 timeout--;
 538
 539                 if (timeout <= 0) {
 540                         dev_err(&i2c->adap.dev, "timeout waiting for SCL high\n");
 541                         break;
 542                 }
 543         }
 544
 545         ICR &= ~ICR_SCLE;
 546 }
 547
 548 static void i2c_pxa_slave_stop(struct pxa_i2c *i2c)
 549 {
 550         if (i2c_debug > 2)
 551                 dev_dbg(&i2c->adap.dev, "ISR: SSD (Slave Stop)\n");
 552
 553         if (i2c->slave != NULL)
 554                 i2c->slave->event(i2c->slave->data, I2C_SLAVE_EVENT_STOP);
 555
 556         if (i2c_debug > 2)
 557                 dev_dbg(&i2c->adap.dev, "ISR: SSD (Slave Stop) acked\n");
 558
 559         /*
 560          * If we have a master-mode message waiting,
 561          * kick it off now that the slave has completed.
 562          */
 563         if (i2c->msg)
 564                 i2c_pxa_master_complete(i2c, I2C_RETRY);
 565 }
 566 #else
 567 static void i2c_pxa_slave_txempty(struct pxa_i2c *i2c, u32 isr)
 568 {
 569         if (isr & ISR_BED) {
 570                 /* what should we do here? */
 571         } else {
 572                 IDBR = 0;
 573                 ICR |= ICR_TB;
 574         }
 575 }
 576
 577 static void i2c_pxa_slave_rxfull(struct pxa_i2c *i2c, u32 isr)
 578 {
 579         ICR |= ICR_TB | ICR_ACKNAK;
 580 }
 581
 582 static void i2c_pxa_slave_start(struct pxa_i2c *i2c, u32 isr)
 583 {
 584         int timeout;
 585
 586         /*
 587          * slave could interrupt in the middle of us generating a
 588          * start condition... if this happens, we'd better back off
 589          * and stop holding the poor thing up
 590          */
 591         ICR &= ~(ICR_START|ICR_STOP);
 592         ICR |= ICR_TB | ICR_ACKNAK;
 593
 594         timeout = 0x10000;
 595
 596         while (1) {
 597                 if ((IBMR & 2) == 2)
 598                         break;
 599
 600                 timeout--;
 601
 602                 if (timeout <= 0) {
 603                         dev_err(&i2c->adap.dev, "timeout waiting for SCL high\n");
 604                         break;
 605                 }
 606         }
 607
 608         ICR &= ~ICR_SCLE;
 609 }
 610
 611 static void i2c_pxa_slave_stop(struct pxa_i2c *i2c)
 612 {
 613         if (i2c->msg)
 614                 i2c_pxa_master_complete(i2c, I2C_RETRY);
 615 }
 616 #endif
 617
 618 /*
 619  * PXA I2C Master mode
 620  */
 621
 622 static inline unsigned int i2c_pxa_addr_byte(struct i2c_msg *msg)
 623 {
 624         unsigned int addr = (msg->addr & 0x7f) << 1;
 625
 626         if (msg->flags & I2C_M_RD)
 627                 addr |= 1;
 628
 629         return addr;
 630 }
 631
 632 static inline void i2c_pxa_start_message(struct pxa_i2c *i2c)
 633 {
 634         u32 icr;
 635
 636         /*
 637          * Step 1: target slave address into IDBR
 638          */
 639         IDBR = i2c_pxa_addr_byte(i2c->msg);
 640
 641         /*
 642          * Step 2: initiate the write.
 643          */
 644         icr = ICR & ~(ICR_STOP | ICR_ALDIE);
 645         ICR = icr | ICR_START | ICR_TB;
 646 }
 647
 648 /*
 649  * We are protected by the adapter bus semaphore.
 650  */
 651 static int i2c_pxa_do_xfer(struct pxa_i2c *i2c, struct i2c_msg *msg, int num)
 652 {
 653         long timeout;
 654         int ret;
 655
 656         /*
 657          * Wait for the bus to become free.
 658          */
 659         ret = i2c_pxa_wait_bus_not_busy(i2c);
 660         if (ret) {
 661                 dev_err(&i2c->adap.dev, "i2c_pxa: timeout waiting for bus free\n");
 662                 goto out;
 663         }
 664
 665         /*
 666          * Set master mode.
 667          */
 668         ret = i2c_pxa_set_master(i2c);
 669         if (ret) {
 670                 dev_err(&i2c->adap.dev, "i2c_pxa_set_master: error %d\n", ret);
 671                 goto out;
 672         }
 673
 674         spin_lock_irq(&i2c->lock);
 675
 676         i2c->msg = msg;
 677         i2c->msg_num = num;
 678         i2c->msg_idx = 0;
 679         i2c->msg_ptr = 0;
 680         i2c->irqlogidx = 0;
 681
 682         i2c_pxa_start_message(i2c);
 683
 684         spin_unlock_irq(&i2c->lock);
 685
 686         /*
 687          * The rest of the processing occurs in the interrupt handler.
 688          */
 689         timeout = wait_event_timeout(i2c->wait, i2c->msg_num == 0, HZ * 5);
 690
 691         /*
 692          * We place the return code in i2c->msg_idx.
 693          */
 694         ret = i2c->msg_idx;
 695
 696         if (timeout == 0)
 697                 i2c_pxa_scream_blue_murder(i2c, "timeout");
 698
 699  out:
 700         return ret;
 701 }
 702
 703 /*
 704  * i2c_pxa_master_complete - complete the message and wake up.
 705  */
 706 static void i2c_pxa_master_complete(struct pxa_i2c *i2c, int ret)
 707 {
 708         i2c->msg_ptr = 0;
 709         i2c->msg = NULL;
 710         i2c->msg_idx ++;
 711         i2c->msg_num = 0;
 712         if (ret)
 713                 i2c->msg_idx = ret;
 714         wake_up(&i2c->wait);
 715 }
 716
 717 static void i2c_pxa_irq_txempty(struct pxa_i2c *i2c, u32 isr)
 718 {
 719         u32 icr = ICR & ~(ICR_START|ICR_STOP|ICR_ACKNAK|ICR_TB);
 720
 721  again:
 722         /*
 723          * If ISR_ALD is set, we lost arbitration.
 724          */
 725         if (isr & ISR_ALD) {
 726                 /*
 727                  * Do we need to do anything here?  The PXA docs
 728                  * are vague about what happens.
 729                  */
 730                 i2c_pxa_scream_blue_murder(i2c, "ALD set");
 731
 732                 /*
 733                  * We ignore this error.  We seem to see spurious ALDs
 734                  * for seemingly no reason.  If we handle them as I think
 735                  * they should, we end up causing an I2C error, which
 736                  * is painful for some systems.
 737                  */
 738                 return; /* ignore */
 739         }
 740
 741         if (isr & ISR_BED) {
 742                 int ret = BUS_ERROR;
 743
 744                 /*
 745                  * I2C bus error - either the device NAK'd us, or
 746                  * something more serious happened.  If we were NAK'd
 747                  * on the initial address phase, we can retry.
 748                  */
 749                 if (isr & ISR_ACKNAK) {
 750                         if (i2c->msg_ptr == 0 && i2c->msg_idx == 0)
 751                                 ret = I2C_RETRY;
 752                         else
 753                                 ret = XFER_NAKED;
 754                 }
 755                 i2c_pxa_master_complete(i2c, ret);
 756         } else if (isr & ISR_RWM) {
 757                 /*
 758                  * Read mode.  We have just sent the address byte, and
 759                  * now we must initiate the transfer.
 760                  */
 761                 if (i2c->msg_ptr == i2c->msg->len - 1 &&
 762                     i2c->msg_idx == i2c->msg_num - 1)
 763                         icr |= ICR_STOP | ICR_ACKNAK;
 764
 765                 icr |= ICR_ALDIE | ICR_TB;
 766         } else if (i2c->msg_ptr < i2c->msg->len) {
 767                 /*
 768                  * Write mode.  Write the next data byte.
 769                  */
 770                 IDBR = i2c->msg->buf[i2c->msg_ptr++];
 771
 772                 icr |= ICR_ALDIE | ICR_TB;
 773
 774                 /*
 775                  * If this is the last byte of the last message, send
 776                  * a STOP.
 777                  */
 778                 if (i2c->msg_ptr == i2c->msg->len &&
 779                     i2c->msg_idx == i2c->msg_num - 1)
 780                         icr |= ICR_STOP;
 781         } else if (i2c->msg_idx < i2c->msg_num - 1) {
 782                 /*
 783                  * Next segment of the message.
 784                  */
 785                 i2c->msg_ptr = 0;
 786                 i2c->msg_idx ++;
 787                 i2c->msg++;
 788
 789                 /*
 790                  * If we aren't doing a repeated start and address,
 791                  * go back and try to send the next byte.  Note that
 792                  * we do not support switching the R/W direction here.
 793                  */
 794                 if (i2c->msg->flags & I2C_M_NOSTART)
 795                         goto again;
 796
 797                 /*
 798                  * Write the next address.
 799                  */
 800                 IDBR = i2c_pxa_addr_byte(i2c->msg);
 801
 802                 /*
 803                  * And trigger a repeated start, and send the byte.
 804                  */
 805                 icr &= ~ICR_ALDIE;
 806                 icr |= ICR_START | ICR_TB;
 807         } else {
 808                 if (i2c->msg->len == 0) {
 809                         /*
 810                          * Device probes have a message length of zero
 811                          * and need the bus to be reset before it can
 812                          * be used again.
 813                          */
 814                         i2c_pxa_reset(i2c);
 815                 }
 816                 i2c_pxa_master_complete(i2c, 0);
 817         }
 818
 819         i2c->icrlog[i2c->irqlogidx-1] = icr;
 820
 821         ICR = icr;
 822         show_state(i2c);
 823 }
 824
 825 static void i2c_pxa_irq_rxfull(struct pxa_i2c *i2c, u32 isr)
 826 {
 827         u32 icr = ICR & ~(ICR_START|ICR_STOP|ICR_ACKNAK|ICR_TB);
 828
 829         /*
 830          * Read the byte.
 831          */
 832         i2c->msg->buf[i2c->msg_ptr++] = IDBR;
 833
 834         if (i2c->msg_ptr < i2c->msg->len) {
 835                 /*
 836                  * If this is the last byte of the last
 837                  * message, send a STOP.
 838                  */
 839                 if (i2c->msg_ptr == i2c->msg->len - 1)
 840                         icr |= ICR_STOP | ICR_ACKNAK;
 841
 842                 icr |= ICR_ALDIE | ICR_TB;
 843         } else {
 844                 i2c_pxa_master_complete(i2c, 0);
 845         }
 846
 847         i2c->icrlog[i2c->irqlogidx-1] = icr;
 848
 849         ICR = icr;
 850 }
 851
 852 static irqreturn_t i2c_pxa_handler(int this_irq, void *dev_id, struct pt_regs *regs)
 853 {
 854         struct pxa_i2c *i2c = dev_id;
 855         u32 isr = ISR;
 856
 857         if (i2c_debug > 2 && 0) {
 858                 dev_dbg(&i2c->adap.dev, "%s: ISR=%08x, ICR=%08x, IBMR=%02x\n",
 859                         __func__, isr, ICR, IBMR);
 860                 decode_ISR(isr);
 861         }
 862
 863         if (i2c->irqlogidx < sizeof(i2c->isrlog)/sizeof(u32))
 864                 i2c->isrlog[i2c->irqlogidx++] = isr;
 865
 866         show_state(i2c);
 867
 868         /*
 869          * Always clear all pending IRQs.
 870          */
 871         ISR = isr & (ISR_SSD|ISR_ALD|ISR_ITE|ISR_IRF|ISR_SAD|ISR_BED);
 872
 873         if (isr & ISR_SAD)
 874                 i2c_pxa_slave_start(i2c, isr);
 875         if (isr & ISR_SSD)
 876                 i2c_pxa_slave_stop(i2c);
 877
 878         if (i2c_pxa_is_slavemode(i2c)) {
 879                 if (isr & ISR_ITE)
 880                         i2c_pxa_slave_txempty(i2c, isr);
 881                 if (isr & ISR_IRF)
 882                         i2c_pxa_slave_rxfull(i2c, isr);
 883         } else if (i2c->msg) {
 884                 if (isr & ISR_ITE)
 885                         i2c_pxa_irq_txempty(i2c, isr);
 886                 if (isr & ISR_IRF)
 887                         i2c_pxa_irq_rxfull(i2c, isr);
 888         } else {
 889                 i2c_pxa_scream_blue_murder(i2c, "spurious irq");
 890         }
 891
 892         return IRQ_HANDLED;
 893 }
 894
 895
 896 static int i2c_pxa_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
 897 {
 898         struct pxa_i2c *i2c = adap->algo_data;
 899         int ret, i;
 900
 901         for (i = adap->retries; i >= 0; i--) {
 902                 ret = i2c_pxa_do_xfer(i2c, msgs, num);
 903                 if (ret != I2C_RETRY)
 904                         goto out;
 905
 906                 if (i2c_debug)
 907                         dev_dbg(&adap->dev, "Retrying transmission\n");
 908                 udelay(100);
 909         }
 910         i2c_pxa_scream_blue_murder(i2c, "exhausted retries");
 911         ret = -EREMOTEIO;
 912  out:
 913         i2c_pxa_set_slave(i2c, ret);
 914         return ret;
 915 }
 916
 917 static u32 i2c_pxa_functionality(struct i2c_adapter *adap)
 918 {
 919         return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
 920 }
 921
 922 static struct i2c_algorithm i2c_pxa_algorithm = {
 923         .master_xfer    = i2c_pxa_xfer,
 924         .functionality  = i2c_pxa_functionality,
 925 };
 926
 927 static struct pxa_i2c i2c_pxa = {
 928         .lock   = SPIN_LOCK_UNLOCKED,
 929         .wait   = __WAIT_QUEUE_HEAD_INITIALIZER(i2c_pxa.wait),
 930         .adap   = {
 931                 .owner          = THIS_MODULE,
 932                 .algo           = &i2c_pxa_algorithm,
 933                 .name           = "pxa2xx-i2c",
 934                 .retries        = 5,
 935         },
 936 };
 937
 938 static int i2c_pxa_probe(struct device *dev)
 939 {
 940         struct pxa_i2c *i2c = &i2c_pxa;
 941         struct i2c_pxa_platform_data *plat = dev->platform_data;
 942         int ret;
 943
 944 #ifdef CONFIG_PXA27x
 945         pxa_gpio_mode(GPIO117_I2CSCL_MD);
 946         pxa_gpio_mode(GPIO118_I2CSDA_MD);
 947         udelay(100);
 948 #endif
 949
 950         i2c->slave_addr = I2C_PXA_SLAVE_ADDR;
 951
 952 #ifdef CONFIG_I2C_PXA_SLAVE
 953         i2c->slave = &eeprom_client;
 954         if (plat) {
 955                 i2c->slave_addr = plat->slave_addr;
 956                 if (plat->slave)
 957                         i2c->slave = plat->slave;
 958         }
 959 #endif
 960
 961         pxa_set_cken(CKEN14_I2C, 1);
 962         ret = request_irq(IRQ_I2C, i2c_pxa_handler, SA_INTERRUPT,
 963                           "pxa2xx-i2c", i2c);
 964         if (ret)
 965                 goto out;
 966
 967         i2c_pxa_reset(i2c);
 968
 969         i2c->adap.algo_data = i2c;
 970         i2c->adap.dev.parent = dev;
 971
 972         ret = i2c_add_adapter(&i2c->adap);
 973         if (ret < 0) {
 974                 printk(KERN_INFO "I2C: Failed to add bus\n");
 975                 goto err_irq;
 976         }
 977
 978         dev_set_drvdata(dev, i2c);
 979
 980 #ifdef CONFIG_I2C_PXA_SLAVE
 981         printk(KERN_INFO "I2C: %s: PXA I2C adapter, slave address %d\n",
 982                i2c->adap.dev.bus_id, i2c->slave_addr);
 983 #else
 984         printk(KERN_INFO "I2C: %s: PXA I2C adapter\n",
 985                i2c->adap.dev.bus_id);
 986 #endif
 987         return 0;
 988
 989  err_irq:
 990         free_irq(IRQ_I2C, i2c);
 991  out:
 992         return ret;
 993 }
 994
 995 static int i2c_pxa_remove(struct device *dev)
 996 {
 997         struct pxa_i2c *i2c = dev_get_drvdata(dev);
 998
 999         dev_set_drvdata(dev, NULL);
1000
1001         i2c_del_adapter(&i2c->adap);
1002         free_irq(IRQ_I2C, i2c);
1003         pxa_set_cken(CKEN14_I2C, 0);
1004
1005         return 0;
1006 }
1007
1008 static struct device_driver i2c_pxa_driver = {
1009         .name           = "pxa2xx-i2c",
1010         .bus            = &platform_bus_type,
1011         .probe          = i2c_pxa_probe,
1012         .remove         = i2c_pxa_remove,
1013 };
1014
1015 static int __init i2c_adap_pxa_init(void)
1016 {
1017         return driver_register(&i2c_pxa_driver);
1018 }
1019
1020 static void i2c_adap_pxa_exit(void)
1021 {
1022         return driver_unregister(&i2c_pxa_driver);
1023 }
1024
1025 module_init(i2c_adap_pxa_init);
1026 module_exit(i2c_adap_pxa_exit);