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)) == 0 ||
 276                     (ISR & ISR_SAD) != 0 ||
 277                     (ICR & ICR_SCLE) == 0) {
 278                         if (i2c_debug > 1)
 279                                 dev_dbg(&i2c->adap.dev, "%s: done\n", __func__);
 280                         return 1;
 281                 }
 282
 283                 msleep(1);
 284         }
 285
 286         if (i2c_debug > 0)
 287                 dev_dbg(&i2c->adap.dev, "%s: did not free\n", __func__);
 288         return 0;
 289 }
 290
 291 /*
 292  * clear the hold on the bus, and take of anything else
 293  * that has been configured
 294  */
 295 static void i2c_pxa_set_slave(struct pxa_i2c *i2c, int errcode)
 296 {
 297         show_state(i2c);
 298
 299         if (errcode < 0) {
 300                 udelay(100);   /* simple delay */
 301         } else {
 302                 /* we need to wait for the stop condition to end */
 303
 304                 /* if we where in stop, then clear... */
 305                 if (ICR & ICR_STOP) {
 306                         udelay(100);
 307                         ICR &= ~ICR_STOP;
 308                 }
 309
 310                 if (!i2c_pxa_wait_slave(i2c)) {
 311                         dev_err(&i2c->adap.dev, "%s: wait timedout\n",
 312                                 __func__);
 313                         return;
 314                 }
 315         }
 316
 317         ICR &= ~(ICR_STOP|ICR_ACKNAK|ICR_MA);
 318         ICR &= ~ICR_SCLE;
 319
 320         if (i2c_debug) {
 321                 dev_dbg(&i2c->adap.dev, "ICR now %08x, ISR %08x\n", ICR, ISR);
 322                 decode_ICR(ICR);
 323         }
 324 }
 325 #else
 326 #define i2c_pxa_set_slave(i2c, err)     do { } while (0)
 327 #endif
 328
 329 static void i2c_pxa_reset(struct pxa_i2c *i2c)
 330 {
 331         pr_debug("Resetting I2C Controller Unit\n");
 332
 333         /* abort any transfer currently under way */
 334         i2c_pxa_abort(i2c);
 335
 336         /* reset according to 9.8 */
 337         ICR = ICR_UR;
 338         ISR = I2C_ISR_INIT;
 339         ICR &= ~ICR_UR;
 340
 341         ISAR = i2c->slave_addr;
 342
 343         /* set control register values */
 344         ICR = I2C_ICR_INIT;
 345
 346 #ifdef CONFIG_I2C_PXA_SLAVE
 347         dev_info(&i2c->adap.dev, "Enabling slave mode\n");
 348         ICR |= ICR_SADIE | ICR_ALDIE | ICR_SSDIE;
 349 #endif
 350
 351         i2c_pxa_set_slave(i2c, 0);
 352
 353         /* enable unit */
 354         ICR |= ICR_IUE;
 355         udelay(100);
 356 }
 357
 358
 359 #ifdef CONFIG_I2C_PXA_SLAVE
 360 /*
 361  * PXA I2C Slave mode
 362  */
 363
 364 static void i2c_pxa_slave_txempty(struct pxa_i2c *i2c, u32 isr)
 365 {
 366         if (isr & ISR_BED) {
 367                 /* what should we do here? */
 368         } else {
 369                 int ret = 0;
 370
 371                 if (i2c->slave != NULL)
 372                         ret = i2c->slave->read(i2c->slave->data);
 373
 374                 IDBR = ret;
 375                 ICR |= ICR_TB;   /* allow next byte */
 376         }
 377 }
 378
 379 static void i2c_pxa_slave_rxfull(struct pxa_i2c *i2c, u32 isr)
 380 {
 381         unsigned int byte = IDBR;
 382
 383         if (i2c->slave != NULL)
 384                 i2c->slave->write(i2c->slave->data, byte);
 385
 386         ICR |= ICR_TB;
 387 }
 388
 389 static void i2c_pxa_slave_start(struct pxa_i2c *i2c, u32 isr)
 390 {
 391         int timeout;
 392
 393         if (i2c_debug > 0)
 394                 dev_dbg(&i2c->adap.dev, "SAD, mode is slave-%cx\n",
 395                        (isr & ISR_RWM) ? 'r' : 't');
 396
 397         if (i2c->slave != NULL)
 398                 i2c->slave->event(i2c->slave->data,
 399                                  (isr & ISR_RWM) ? I2C_SLAVE_EVENT_START_READ : I2C_SLAVE_EVENT_START_WRITE);
 400
 401         /*
 402          * slave could interrupt in the middle of us generating a
 403          * start condition... if this happens, we'd better back off
 404          * and stop holding the poor thing up
 405          */
 406         ICR &= ~(ICR_START|ICR_STOP);
 407         ICR |= ICR_TB;
 408
 409         timeout = 0x10000;
 410
 411         while (1) {
 412                 if ((IBMR & 2) == 2)
 413                         break;
 414
 415                 timeout--;
 416
 417                 if (timeout <= 0) {
 418                         dev_err(&i2c->adap.dev, "timeout waiting for SCL high\n");
 419                         break;
 420                 }
 421         }
 422
 423         ICR &= ~ICR_SCLE;
 424 }
 425
 426 static void i2c_pxa_slave_stop(struct pxa_i2c *i2c)
 427 {
 428         if (i2c_debug > 2)
 429                 dev_dbg(&i2c->adap.dev, "ISR: SSD (Slave Stop)\n");
 430
 431         if (i2c->slave != NULL)
 432                 i2c->slave->event(i2c->slave->data, I2C_SLAVE_EVENT_STOP);
 433
 434         if (i2c_debug > 2)
 435                 dev_dbg(&i2c->adap.dev, "ISR: SSD (Slave Stop) acked\n");
 436
 437         /*
 438          * If we have a master-mode message waiting,
 439          * kick it off now that the slave has completed.
 440          */
 441         if (i2c->msg)
 442                 i2c_pxa_master_complete(i2c, I2C_RETRY);
 443 }
 444 #else
 445 static void i2c_pxa_slave_txempty(struct pxa_i2c *i2c, u32 isr)
 446 {
 447         if (isr & ISR_BED) {
 448                 /* what should we do here? */
 449         } else {
 450                 IDBR = 0;
 451                 ICR |= ICR_TB;
 452         }
 453 }
 454
 455 static void i2c_pxa_slave_rxfull(struct pxa_i2c *i2c, u32 isr)
 456 {
 457         ICR |= ICR_TB | ICR_ACKNAK;
 458 }
 459
 460 static void i2c_pxa_slave_start(struct pxa_i2c *i2c, u32 isr)
 461 {
 462         int timeout;
 463
 464         /*
 465          * slave could interrupt in the middle of us generating a
 466          * start condition... if this happens, we'd better back off
 467          * and stop holding the poor thing up
 468          */
 469         ICR &= ~(ICR_START|ICR_STOP);
 470         ICR |= ICR_TB | ICR_ACKNAK;
 471
 472         timeout = 0x10000;
 473
 474         while (1) {
 475                 if ((IBMR & 2) == 2)
 476                         break;
 477
 478                 timeout--;
 479
 480                 if (timeout <= 0) {
 481                         dev_err(&i2c->adap.dev, "timeout waiting for SCL high\n");
 482                         break;
 483                 }
 484         }
 485
 486         ICR &= ~ICR_SCLE;
 487 }
 488
 489 static void i2c_pxa_slave_stop(struct pxa_i2c *i2c)
 490 {
 491         if (i2c->msg)
 492                 i2c_pxa_master_complete(i2c, I2C_RETRY);
 493 }
 494 #endif
 495
 496 /*
 497  * PXA I2C Master mode
 498  */
 499
 500 static inline unsigned int i2c_pxa_addr_byte(struct i2c_msg *msg)
 501 {
 502         unsigned int addr = (msg->addr & 0x7f) << 1;
 503
 504         if (msg->flags & I2C_M_RD)
 505                 addr |= 1;
 506
 507         return addr;
 508 }
 509
 510 static inline void i2c_pxa_start_message(struct pxa_i2c *i2c)
 511 {
 512         u32 icr;
 513
 514         /*
 515          * Step 1: target slave address into IDBR
 516          */
 517         IDBR = i2c_pxa_addr_byte(i2c->msg);
 518
 519         /*
 520          * Step 2: initiate the write.
 521          */
 522         icr = ICR & ~(ICR_STOP | ICR_ALDIE);
 523         ICR = icr | ICR_START | ICR_TB;
 524 }
 525
 526 /*
 527  * We are protected by the adapter bus mutex.
 528  */
 529 static int i2c_pxa_do_xfer(struct pxa_i2c *i2c, struct i2c_msg *msg, int num)
 530 {
 531         long timeout;
 532         int ret;
 533
 534         /*
 535          * Wait for the bus to become free.
 536          */
 537         ret = i2c_pxa_wait_bus_not_busy(i2c);
 538         if (ret) {
 539                 dev_err(&i2c->adap.dev, "i2c_pxa: timeout waiting for bus free\n");
 540                 goto out;
 541         }
 542
 543         /*
 544          * Set master mode.
 545          */
 546         ret = i2c_pxa_set_master(i2c);
 547         if (ret) {
 548                 dev_err(&i2c->adap.dev, "i2c_pxa_set_master: error %d\n", ret);
 549                 goto out;
 550         }
 551
 552         spin_lock_irq(&i2c->lock);
 553
 554         i2c->msg = msg;
 555         i2c->msg_num = num;
 556         i2c->msg_idx = 0;
 557         i2c->msg_ptr = 0;
 558         i2c->irqlogidx = 0;
 559
 560         i2c_pxa_start_message(i2c);
 561
 562         spin_unlock_irq(&i2c->lock);
 563
 564         /*
 565          * The rest of the processing occurs in the interrupt handler.
 566          */
 567         timeout = wait_event_timeout(i2c->wait, i2c->msg_num == 0, HZ * 5);
 568
 569         /*
 570          * We place the return code in i2c->msg_idx.
 571          */
 572         ret = i2c->msg_idx;
 573
 574         if (timeout == 0)
 575                 i2c_pxa_scream_blue_murder(i2c, "timeout");
 576
 577  out:
 578         return ret;
 579 }
 580
 581 /*
 582  * i2c_pxa_master_complete - complete the message and wake up.
 583  */
 584 static void i2c_pxa_master_complete(struct pxa_i2c *i2c, int ret)
 585 {
 586         i2c->msg_ptr = 0;
 587         i2c->msg = NULL;
 588         i2c->msg_idx ++;
 589         i2c->msg_num = 0;
 590         if (ret)
 591                 i2c->msg_idx = ret;
 592         wake_up(&i2c->wait);
 593 }
 594
 595 static void i2c_pxa_irq_txempty(struct pxa_i2c *i2c, u32 isr)
 596 {
 597         u32 icr = ICR & ~(ICR_START|ICR_STOP|ICR_ACKNAK|ICR_TB);
 598
 599  again:
 600         /*
 601          * If ISR_ALD is set, we lost arbitration.
 602          */
 603         if (isr & ISR_ALD) {
 604                 /*
 605                  * Do we need to do anything here?  The PXA docs
 606                  * are vague about what happens.
 607                  */
 608                 i2c_pxa_scream_blue_murder(i2c, "ALD set");
 609
 610                 /*
 611                  * We ignore this error.  We seem to see spurious ALDs
 612                  * for seemingly no reason.  If we handle them as I think
 613                  * they should, we end up causing an I2C error, which
 614                  * is painful for some systems.
 615                  */
 616                 return; /* ignore */
 617         }
 618
 619         if (isr & ISR_BED) {
 620                 int ret = BUS_ERROR;
 621
 622                 /*
 623                  * I2C bus error - either the device NAK'd us, or
 624                  * something more serious happened.  If we were NAK'd
 625                  * on the initial address phase, we can retry.
 626                  */
 627                 if (isr & ISR_ACKNAK) {
 628                         if (i2c->msg_ptr == 0 && i2c->msg_idx == 0)
 629                                 ret = I2C_RETRY;
 630                         else
 631                                 ret = XFER_NAKED;
 632                 }
 633                 i2c_pxa_master_complete(i2c, ret);
 634         } else if (isr & ISR_RWM) {
 635                 /*
 636                  * Read mode.  We have just sent the address byte, and
 637                  * now we must initiate the transfer.
 638                  */
 639                 if (i2c->msg_ptr == i2c->msg->len - 1 &&
 640                     i2c->msg_idx == i2c->msg_num - 1)
 641                         icr |= ICR_STOP | ICR_ACKNAK;
 642
 643                 icr |= ICR_ALDIE | ICR_TB;
 644         } else if (i2c->msg_ptr < i2c->msg->len) {
 645                 /*
 646                  * Write mode.  Write the next data byte.
 647                  */
 648                 IDBR = i2c->msg->buf[i2c->msg_ptr++];
 649
 650                 icr |= ICR_ALDIE | ICR_TB;
 651
 652                 /*
 653                  * If this is the last byte of the last message, send
 654                  * a STOP.
 655                  */
 656                 if (i2c->msg_ptr == i2c->msg->len &&
 657                     i2c->msg_idx == i2c->msg_num - 1)
 658                         icr |= ICR_STOP;
 659         } else if (i2c->msg_idx < i2c->msg_num - 1) {
 660                 /*
 661                  * Next segment of the message.
 662                  */
 663                 i2c->msg_ptr = 0;
 664                 i2c->msg_idx ++;
 665                 i2c->msg++;
 666
 667                 /*
 668                  * If we aren't doing a repeated start and address,
 669                  * go back and try to send the next byte.  Note that
 670                  * we do not support switching the R/W direction here.
 671                  */
 672                 if (i2c->msg->flags & I2C_M_NOSTART)
 673                         goto again;
 674
 675                 /*
 676                  * Write the next address.
 677                  */
 678                 IDBR = i2c_pxa_addr_byte(i2c->msg);
 679
 680                 /*
 681                  * And trigger a repeated start, and send the byte.
 682                  */
 683                 icr &= ~ICR_ALDIE;
 684                 icr |= ICR_START | ICR_TB;
 685         } else {
 686                 if (i2c->msg->len == 0) {
 687                         /*
 688                          * Device probes have a message length of zero
 689                          * and need the bus to be reset before it can
 690                          * be used again.
 691                          */
 692                         i2c_pxa_reset(i2c);
 693                 }
 694                 i2c_pxa_master_complete(i2c, 0);
 695         }
 696
 697         i2c->icrlog[i2c->irqlogidx-1] = icr;
 698
 699         ICR = icr;
 700         show_state(i2c);
 701 }
 702
 703 static void i2c_pxa_irq_rxfull(struct pxa_i2c *i2c, u32 isr)
 704 {
 705         u32 icr = ICR & ~(ICR_START|ICR_STOP|ICR_ACKNAK|ICR_TB);
 706
 707         /*
 708          * Read the byte.
 709          */
 710         i2c->msg->buf[i2c->msg_ptr++] = IDBR;
 711
 712         if (i2c->msg_ptr < i2c->msg->len) {
 713                 /*
 714                  * If this is the last byte of the last
 715                  * message, send a STOP.
 716                  */
 717                 if (i2c->msg_ptr == i2c->msg->len - 1)
 718                         icr |= ICR_STOP | ICR_ACKNAK;
 719
 720                 icr |= ICR_ALDIE | ICR_TB;
 721         } else {
 722                 i2c_pxa_master_complete(i2c, 0);
 723         }
 724
 725         i2c->icrlog[i2c->irqlogidx-1] = icr;
 726
 727         ICR = icr;
 728 }
 729
 730 static irqreturn_t i2c_pxa_handler(int this_irq, void *dev_id)
 731 {
 732         struct pxa_i2c *i2c = dev_id;
 733         u32 isr = ISR;
 734
 735         if (i2c_debug > 2 && 0) {
 736                 dev_dbg(&i2c->adap.dev, "%s: ISR=%08x, ICR=%08x, IBMR=%02x\n",
 737                         __func__, isr, ICR, IBMR);
 738                 decode_ISR(isr);
 739         }
 740
 741         if (i2c->irqlogidx < ARRAY_SIZE(i2c->isrlog))
 742                 i2c->isrlog[i2c->irqlogidx++] = isr;
 743
 744         show_state(i2c);
 745
 746         /*
 747          * Always clear all pending IRQs.
 748          */
 749         ISR = isr & (ISR_SSD|ISR_ALD|ISR_ITE|ISR_IRF|ISR_SAD|ISR_BED);
 750
 751         if (isr & ISR_SAD)
 752                 i2c_pxa_slave_start(i2c, isr);
 753         if (isr & ISR_SSD)
 754                 i2c_pxa_slave_stop(i2c);
 755
 756         if (i2c_pxa_is_slavemode(i2c)) {
 757                 if (isr & ISR_ITE)
 758                         i2c_pxa_slave_txempty(i2c, isr);
 759                 if (isr & ISR_IRF)
 760                         i2c_pxa_slave_rxfull(i2c, isr);
 761         } else if (i2c->msg) {
 762                 if (isr & ISR_ITE)
 763                         i2c_pxa_irq_txempty(i2c, isr);
 764                 if (isr & ISR_IRF)
 765                         i2c_pxa_irq_rxfull(i2c, isr);
 766         } else {
 767                 i2c_pxa_scream_blue_murder(i2c, "spurious irq");
 768         }
 769
 770         return IRQ_HANDLED;
 771 }
 772
 773
 774 static int i2c_pxa_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
 775 {
 776         struct pxa_i2c *i2c = adap->algo_data;
 777         int ret, i;
 778
 779         /* If the I2C controller is disabled we need to reset it (probably due
 780            to a suspend/resume destroying state). We do this here as we can then
 781            avoid worrying about resuming the controller before its users. */
 782         if (!(ICR & ICR_IUE))
 783                 i2c_pxa_reset(i2c);
 784
 785         for (i = adap->retries; i >= 0; i--) {
 786                 ret = i2c_pxa_do_xfer(i2c, msgs, num);
 787                 if (ret != I2C_RETRY)
 788                         goto out;
 789
 790                 if (i2c_debug)
 791                         dev_dbg(&adap->dev, "Retrying transmission\n");
 792                 udelay(100);
 793         }
 794         i2c_pxa_scream_blue_murder(i2c, "exhausted retries");
 795         ret = -EREMOTEIO;
 796  out:
 797         i2c_pxa_set_slave(i2c, ret);
 798         return ret;
 799 }
 800
 801 static u32 i2c_pxa_functionality(struct i2c_adapter *adap)
 802 {
 803         return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
 804 }
 805
 806 static const struct i2c_algorithm i2c_pxa_algorithm = {
 807         .master_xfer    = i2c_pxa_xfer,
 808         .functionality  = i2c_pxa_functionality,
 809 };
 810
 811 static struct pxa_i2c i2c_pxa = {
 812         .lock   = SPIN_LOCK_UNLOCKED,
 813         .wait   = __WAIT_QUEUE_HEAD_INITIALIZER(i2c_pxa.wait),
 814         .adap   = {
 815                 .owner          = THIS_MODULE,
 816                 .algo           = &i2c_pxa_algorithm,
 817                 .name           = "pxa2xx-i2c",
 818                 .retries        = 5,
 819         },
 820 };
 821
 822 static int i2c_pxa_probe(struct platform_device *dev)
 823 {
 824         struct pxa_i2c *i2c = &i2c_pxa;
 825 #ifdef CONFIG_I2C_PXA_SLAVE
 826         struct i2c_pxa_platform_data *plat = dev->dev.platform_data;
 827 #endif
 828         int ret;
 829
 830 #ifdef CONFIG_PXA27x
 831         pxa_gpio_mode(GPIO117_I2CSCL_MD);
 832         pxa_gpio_mode(GPIO118_I2CSDA_MD);
 833         udelay(100);
 834 #endif
 835
 836         i2c->slave_addr = I2C_PXA_SLAVE_ADDR;
 837
 838 #ifdef CONFIG_I2C_PXA_SLAVE
 839         if (plat) {
 840                 i2c->slave_addr = plat->slave_addr;
 841                 i2c->slave = plat->slave;
 842         }
 843 #endif
 844
 845         pxa_set_cken(CKEN14_I2C, 1);
 846         ret = request_irq(IRQ_I2C, i2c_pxa_handler, IRQF_DISABLED,
 847                           "pxa2xx-i2c", i2c);
 848         if (ret)
 849                 goto out;
 850
 851         i2c_pxa_reset(i2c);
 852
 853         i2c->adap.algo_data = i2c;
 854         i2c->adap.dev.parent = &dev->dev;
 855
 856         ret = i2c_add_adapter(&i2c->adap);
 857         if (ret < 0) {
 858                 printk(KERN_INFO "I2C: Failed to add bus\n");
 859                 goto err_irq;
 860         }
 861
 862         platform_set_drvdata(dev, i2c);
 863
 864 #ifdef CONFIG_I2C_PXA_SLAVE
 865         printk(KERN_INFO "I2C: %s: PXA I2C adapter, slave address %d\n",
 866                i2c->adap.dev.bus_id, i2c->slave_addr);
 867 #else
 868         printk(KERN_INFO "I2C: %s: PXA I2C adapter\n",
 869                i2c->adap.dev.bus_id);
 870 #endif
 871         return 0;
 872
 873  err_irq:
 874         free_irq(IRQ_I2C, i2c);
 875  out:
 876         return ret;
 877 }
 878
 879 static int i2c_pxa_remove(struct platform_device *dev)
 880 {
 881         struct pxa_i2c *i2c = platform_get_drvdata(dev);
 882
 883         platform_set_drvdata(dev, NULL);
 884
 885         i2c_del_adapter(&i2c->adap);
 886         free_irq(IRQ_I2C, i2c);
 887         pxa_set_cken(CKEN14_I2C, 0);
 888
 889         return 0;
 890 }
 891
 892 static struct platform_driver i2c_pxa_driver = {
 893         .probe          = i2c_pxa_probe,
 894         .remove         = i2c_pxa_remove,
 895         .driver         = {
 896                 .name   = "pxa2xx-i2c",
 897         },
 898 };
 899
 900 static int __init i2c_adap_pxa_init(void)
 901 {
 902         return platform_driver_register(&i2c_pxa_driver);
 903 }
 904
 905 static void i2c_adap_pxa_exit(void)
 906 {
 907         return platform_driver_unregister(&i2c_pxa_driver);
 908 }
 909
 910 MODULE_LICENSE("GPL");
 911
 912 module_init(i2c_adap_pxa_init);
 913 module_exit(i2c_adap_pxa_exit);