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 #include <linux/err.h>
  35 #include <linux/clk.h>
  36
  37 #include <asm/hardware.h>
  38 #include <asm/irq.h>
  39 #include <asm/io.h>
  40 #include <asm/arch/i2c.h>
  41 #include <asm/arch/pxa-regs.h>
  42 #include <asm/arch/pxa2xx-gpio.h>
  43
  44 struct pxa_i2c {
  45         spinlock_t              lock;
  46         wait_queue_head_t       wait;
  47         struct i2c_msg          *msg;
  48         unsigned int            msg_num;
  49         unsigned int            msg_idx;
  50         unsigned int            msg_ptr;
  51         unsigned int            slave_addr;
  52
  53         struct i2c_adapter      adap;
  54         struct clk              *clk;
  55 #ifdef CONFIG_I2C_PXA_SLAVE
  56         struct i2c_slave_client *slave;
  57 #endif
  58
  59         unsigned int            irqlogidx;
  60         u32                     isrlog[32];
  61         u32                     icrlog[32];
  62
  63         void __iomem            *reg_base;
  64
  65         unsigned long           iobase;
  66         unsigned long           iosize;
  67
  68         int                     irq;
  69         int                     use_pio;
  70 };
  71
  72 #define _IBMR(i2c)      ((i2c)->reg_base + 0)
  73 #define _IDBR(i2c)      ((i2c)->reg_base + 8)
  74 #define _ICR(i2c)       ((i2c)->reg_base + 0x10)
  75 #define _ISR(i2c)       ((i2c)->reg_base + 0x18)
  76 #define _ISAR(i2c)      ((i2c)->reg_base + 0x20)
  77
  78 /*
  79  * I2C Slave mode address
  80  */
  81 #define I2C_PXA_SLAVE_ADDR      0x1
  82
  83 #ifdef DEBUG
  84
  85 struct bits {
  86         u32     mask;
  87         const char *set;
  88         const char *unset;
  89 };
  90 #define PXA_BIT(m, s, u)        { .mask = m, .set = s, .unset = u }
  91
  92 static inline void
  93 decode_bits(const char *prefix, const struct bits *bits, int num, u32 val)
  94 {
  95         printk("%s %08x: ", prefix, val);
  96         while (num--) {
  97                 const char *str = val & bits->mask ? bits->set : bits->unset;
  98                 if (str)
  99                         printk("%s ", str);
 100                 bits++;
 101         }
 102 }
 103
 104 static const struct bits isr_bits[] = {
 105         PXA_BIT(ISR_RWM,        "RX",           "TX"),
 106         PXA_BIT(ISR_ACKNAK,     "NAK",          "ACK"),
 107         PXA_BIT(ISR_UB,         "Bsy",          "Rdy"),
 108         PXA_BIT(ISR_IBB,        "BusBsy",       "BusRdy"),
 109         PXA_BIT(ISR_SSD,        "SlaveStop",    NULL),
 110         PXA_BIT(ISR_ALD,        "ALD",          NULL),
 111         PXA_BIT(ISR_ITE,        "TxEmpty",      NULL),
 112         PXA_BIT(ISR_IRF,        "RxFull",       NULL),
 113         PXA_BIT(ISR_GCAD,       "GenCall",      NULL),
 114         PXA_BIT(ISR_SAD,        "SlaveAddr",    NULL),
 115         PXA_BIT(ISR_BED,        "BusErr",       NULL),
 116 };
 117
 118 static void decode_ISR(unsigned int val)
 119 {
 120         decode_bits(KERN_DEBUG "ISR", isr_bits, ARRAY_SIZE(isr_bits), val);
 121         printk("\n");
 122 }
 123
 124 static const struct bits icr_bits[] = {
 125         PXA_BIT(ICR_START,  "START",    NULL),
 126         PXA_BIT(ICR_STOP,   "STOP",     NULL),
 127         PXA_BIT(ICR_ACKNAK, "ACKNAK",   NULL),
 128         PXA_BIT(ICR_TB,     "TB",       NULL),
 129         PXA_BIT(ICR_MA,     "MA",       NULL),
 130         PXA_BIT(ICR_SCLE,   "SCLE",     "scle"),
 131         PXA_BIT(ICR_IUE,    "IUE",      "iue"),
 132         PXA_BIT(ICR_GCD,    "GCD",      NULL),
 133         PXA_BIT(ICR_ITEIE,  "ITEIE",    NULL),
 134         PXA_BIT(ICR_IRFIE,  "IRFIE",    NULL),
 135         PXA_BIT(ICR_BEIE,   "BEIE",     NULL),
 136         PXA_BIT(ICR_SSDIE,  "SSDIE",    NULL),
 137         PXA_BIT(ICR_ALDIE,  "ALDIE",    NULL),
 138         PXA_BIT(ICR_SADIE,  "SADIE",    NULL),
 139         PXA_BIT(ICR_UR,     "UR",               "ur"),
 140 };
 141
 142 #ifdef CONFIG_I2C_PXA_SLAVE
 143 static void decode_ICR(unsigned int val)
 144 {
 145         decode_bits(KERN_DEBUG "ICR", icr_bits, ARRAY_SIZE(icr_bits), val);
 146         printk("\n");
 147 }
 148 #endif
 149
 150 static unsigned int i2c_debug = DEBUG;
 151
 152 static void i2c_pxa_show_state(struct pxa_i2c *i2c, int lno, const char *fname)
 153 {
 154         dev_dbg(&i2c->adap.dev, "state:%s:%d: ISR=%08x, ICR=%08x, IBMR=%02x\n", fname, lno,
 155                 readl(_ISR(i2c)), readl(_ICR(i2c)), readl(_IBMR(i2c)));
 156 }
 157
 158 #define show_state(i2c) i2c_pxa_show_state(i2c, __LINE__, __func__)
 159 #else
 160 #define i2c_debug       0
 161
 162 #define show_state(i2c) do { } while (0)
 163 #define decode_ISR(val) do { } while (0)
 164 #define decode_ICR(val) do { } while (0)
 165 #endif
 166
 167 #define eedbg(lvl, x...) do { if ((lvl) < 1) { printk(KERN_DEBUG "" x); } } while(0)
 168
 169 static void i2c_pxa_master_complete(struct pxa_i2c *i2c, int ret);
 170 static irqreturn_t i2c_pxa_handler(int this_irq, void *dev_id);
 171
 172 static void i2c_pxa_scream_blue_murder(struct pxa_i2c *i2c, const char *why)
 173 {
 174         unsigned int i;
 175         printk("i2c: error: %s\n", why);
 176         printk("i2c: msg_num: %d msg_idx: %d msg_ptr: %d\n",
 177                 i2c->msg_num, i2c->msg_idx, i2c->msg_ptr);
 178         printk("i2c: ICR: %08x ISR: %08x\n"
 179                "i2c: log: ", readl(_ICR(i2c)), readl(_ISR(i2c)));
 180         for (i = 0; i < i2c->irqlogidx; i++)
 181                 printk("[%08x:%08x] ", i2c->isrlog[i], i2c->icrlog[i]);
 182         printk("\n");
 183 }
 184
 185 static inline int i2c_pxa_is_slavemode(struct pxa_i2c *i2c)
 186 {
 187         return !(readl(_ICR(i2c)) & ICR_SCLE);
 188 }
 189
 190 static void i2c_pxa_abort(struct pxa_i2c *i2c)
 191 {
 192         unsigned long timeout = jiffies + HZ/4;
 193
 194         if (i2c_pxa_is_slavemode(i2c)) {
 195                 dev_dbg(&i2c->adap.dev, "%s: called in slave mode\n", __func__);
 196                 return;
 197         }
 198
 199         while (time_before(jiffies, timeout) && (readl(_IBMR(i2c)) & 0x1) == 0) {
 200                 unsigned long icr = readl(_ICR(i2c));
 201
 202                 icr &= ~ICR_START;
 203                 icr |= ICR_ACKNAK | ICR_STOP | ICR_TB;
 204
 205                 writel(icr, _ICR(i2c));
 206
 207                 show_state(i2c);
 208
 209                 msleep(1);
 210         }
 211
 212         writel(readl(_ICR(i2c)) & ~(ICR_MA | ICR_START | ICR_STOP),
 213                _ICR(i2c));
 214 }
 215
 216 static int i2c_pxa_wait_bus_not_busy(struct pxa_i2c *i2c)
 217 {
 218         int timeout = DEF_TIMEOUT;
 219
 220         while (timeout-- && readl(_ISR(i2c)) & (ISR_IBB | ISR_UB)) {
 221                 if ((readl(_ISR(i2c)) & ISR_SAD) != 0)
 222                         timeout += 4;
 223
 224                 msleep(2);
 225                 show_state(i2c);
 226         }
 227
 228         if (timeout <= 0)
 229                 show_state(i2c);
 230
 231         return timeout <= 0 ? I2C_RETRY : 0;
 232 }
 233
 234 static int i2c_pxa_wait_master(struct pxa_i2c *i2c)
 235 {
 236         unsigned long timeout = jiffies + HZ*4;
 237
 238         while (time_before(jiffies, timeout)) {
 239                 if (i2c_debug > 1)
 240                         dev_dbg(&i2c->adap.dev, "%s: %ld: ISR=%08x, ICR=%08x, IBMR=%02x\n",
 241                                 __func__, (long)jiffies, readl(_ISR(i2c)), readl(_ICR(i2c)), readl(_IBMR(i2c)));
 242
 243                 if (readl(_ISR(i2c)) & ISR_SAD) {
 244                         if (i2c_debug > 0)
 245                                 dev_dbg(&i2c->adap.dev, "%s: Slave detected\n", __func__);
 246                         goto out;
 247                 }
 248
 249                 /* wait for unit and bus being not busy, and we also do a
 250                  * quick check of the i2c lines themselves to ensure they've
 251                  * gone high...
 252                  */
 253                 if ((readl(_ISR(i2c)) & (ISR_UB | ISR_IBB)) == 0 && readl(_IBMR(i2c)) == 3) {
 254                         if (i2c_debug > 0)
 255                                 dev_dbg(&i2c->adap.dev, "%s: done\n", __func__);
 256                         return 1;
 257                 }
 258
 259                 msleep(1);
 260         }
 261
 262         if (i2c_debug > 0)
 263                 dev_dbg(&i2c->adap.dev, "%s: did not free\n", __func__);
 264  out:
 265         return 0;
 266 }
 267
 268 static int i2c_pxa_set_master(struct pxa_i2c *i2c)
 269 {
 270         if (i2c_debug)
 271                 dev_dbg(&i2c->adap.dev, "setting to bus master\n");
 272
 273         if ((readl(_ISR(i2c)) & (ISR_UB | ISR_IBB)) != 0) {
 274                 dev_dbg(&i2c->adap.dev, "%s: unit is busy\n", __func__);
 275                 if (!i2c_pxa_wait_master(i2c)) {
 276                         dev_dbg(&i2c->adap.dev, "%s: error: unit busy\n", __func__);
 277                         return I2C_RETRY;
 278                 }
 279         }
 280
 281         writel(readl(_ICR(i2c)) | ICR_SCLE, _ICR(i2c));
 282         return 0;
 283 }
 284
 285 #ifdef CONFIG_I2C_PXA_SLAVE
 286 static int i2c_pxa_wait_slave(struct pxa_i2c *i2c)
 287 {
 288         unsigned long timeout = jiffies + HZ*1;
 289
 290         /* wait for stop */
 291
 292         show_state(i2c);
 293
 294         while (time_before(jiffies, timeout)) {
 295                 if (i2c_debug > 1)
 296                         dev_dbg(&i2c->adap.dev, "%s: %ld: ISR=%08x, ICR=%08x, IBMR=%02x\n",
 297                                 __func__, (long)jiffies, readl(_ISR(i2c)), readl(_ICR(i2c)), readl(_IBMR(i2c)));
 298
 299                 if ((readl(_ISR(i2c)) & (ISR_UB|ISR_IBB)) == 0 ||
 300                     (readl(_ISR(i2c)) & ISR_SAD) != 0 ||
 301                     (readl(_ICR(i2c)) & ICR_SCLE) == 0) {
 302                         if (i2c_debug > 1)
 303                                 dev_dbg(&i2c->adap.dev, "%s: done\n", __func__);
 304                         return 1;
 305                 }
 306
 307                 msleep(1);
 308         }
 309
 310         if (i2c_debug > 0)
 311                 dev_dbg(&i2c->adap.dev, "%s: did not free\n", __func__);
 312         return 0;
 313 }
 314
 315 /*
 316  * clear the hold on the bus, and take of anything else
 317  * that has been configured
 318  */
 319 static void i2c_pxa_set_slave(struct pxa_i2c *i2c, int errcode)
 320 {
 321         show_state(i2c);
 322
 323         if (errcode < 0) {
 324                 udelay(100);   /* simple delay */
 325         } else {
 326                 /* we need to wait for the stop condition to end */
 327
 328                 /* if we where in stop, then clear... */
 329                 if (readl(_ICR(i2c)) & ICR_STOP) {
 330                         udelay(100);
 331                         writel(readl(_ICR(i2c)) & ~ICR_STOP, _ICR(i2c));
 332                 }
 333
 334                 if (!i2c_pxa_wait_slave(i2c)) {
 335                         dev_err(&i2c->adap.dev, "%s: wait timedout\n",
 336                                 __func__);
 337                         return;
 338                 }
 339         }
 340
 341         writel(readl(_ICR(i2c)) & ~(ICR_STOP|ICR_ACKNAK|ICR_MA), _ICR(i2c));
 342         writel(readl(_ICR(i2c)) & ~ICR_SCLE, _ICR(i2c));
 343
 344         if (i2c_debug) {
 345                 dev_dbg(&i2c->adap.dev, "ICR now %08x, ISR %08x\n", readl(_ICR(i2c)), readl(_ISR(i2c)));
 346                 decode_ICR(readl(_ICR(i2c)));
 347         }
 348 }
 349 #else
 350 #define i2c_pxa_set_slave(i2c, err)     do { } while (0)
 351 #endif
 352
 353 static void i2c_pxa_reset(struct pxa_i2c *i2c)
 354 {
 355         pr_debug("Resetting I2C Controller Unit\n");
 356
 357         /* abort any transfer currently under way */
 358         i2c_pxa_abort(i2c);
 359
 360         /* reset according to 9.8 */
 361         writel(ICR_UR, _ICR(i2c));
 362         writel(I2C_ISR_INIT, _ISR(i2c));
 363         writel(readl(_ICR(i2c)) & ~ICR_UR, _ICR(i2c));
 364
 365         writel(i2c->slave_addr, _ISAR(i2c));
 366
 367         /* set control register values */
 368         writel(I2C_ICR_INIT, _ICR(i2c));
 369
 370 #ifdef CONFIG_I2C_PXA_SLAVE
 371         dev_info(&i2c->adap.dev, "Enabling slave mode\n");
 372         writel(readl(_ICR(i2c)) | ICR_SADIE | ICR_ALDIE | ICR_SSDIE, _ICR(i2c));
 373 #endif
 374
 375         i2c_pxa_set_slave(i2c, 0);
 376
 377         /* enable unit */
 378         writel(readl(_ICR(i2c)) | ICR_IUE, _ICR(i2c));
 379         udelay(100);
 380 }
 381
 382
 383 #ifdef CONFIG_I2C_PXA_SLAVE
 384 /*
 385  * PXA I2C Slave mode
 386  */
 387
 388 static void i2c_pxa_slave_txempty(struct pxa_i2c *i2c, u32 isr)
 389 {
 390         if (isr & ISR_BED) {
 391                 /* what should we do here? */
 392         } else {
 393                 int ret = 0;
 394
 395                 if (i2c->slave != NULL)
 396                         ret = i2c->slave->read(i2c->slave->data);
 397
 398                 writel(ret, _IDBR(i2c));
 399                 writel(readl(_ICR(i2c)) | ICR_TB, _ICR(i2c));   /* allow next byte */
 400         }
 401 }
 402
 403 static void i2c_pxa_slave_rxfull(struct pxa_i2c *i2c, u32 isr)
 404 {
 405         unsigned int byte = readl(_IDBR(i2c));
 406
 407         if (i2c->slave != NULL)
 408                 i2c->slave->write(i2c->slave->data, byte);
 409
 410         writel(readl(_ICR(i2c)) | ICR_TB, _ICR(i2c));
 411 }
 412
 413 static void i2c_pxa_slave_start(struct pxa_i2c *i2c, u32 isr)
 414 {
 415         int timeout;
 416
 417         if (i2c_debug > 0)
 418                 dev_dbg(&i2c->adap.dev, "SAD, mode is slave-%cx\n",
 419                        (isr & ISR_RWM) ? 'r' : 't');
 420
 421         if (i2c->slave != NULL)
 422                 i2c->slave->event(i2c->slave->data,
 423                                  (isr & ISR_RWM) ? I2C_SLAVE_EVENT_START_READ : I2C_SLAVE_EVENT_START_WRITE);
 424
 425         /*
 426          * slave could interrupt in the middle of us generating a
 427          * start condition... if this happens, we'd better back off
 428          * and stop holding the poor thing up
 429          */
 430         writel(readl(_ICR(i2c)) & ~(ICR_START|ICR_STOP), _ICR(i2c));
 431         writel(readl(_ICR(i2c)) | ICR_TB, _ICR(i2c));
 432
 433         timeout = 0x10000;
 434
 435         while (1) {
 436                 if ((readl(_IBMR(i2c)) & 2) == 2)
 437                         break;
 438
 439                 timeout--;
 440
 441                 if (timeout <= 0) {
 442                         dev_err(&i2c->adap.dev, "timeout waiting for SCL high\n");
 443                         break;
 444                 }
 445         }
 446
 447         writel(readl(_ICR(i2c)) & ~ICR_SCLE, _ICR(i2c));
 448 }
 449
 450 static void i2c_pxa_slave_stop(struct pxa_i2c *i2c)
 451 {
 452         if (i2c_debug > 2)
 453                 dev_dbg(&i2c->adap.dev, "ISR: SSD (Slave Stop)\n");
 454
 455         if (i2c->slave != NULL)
 456                 i2c->slave->event(i2c->slave->data, I2C_SLAVE_EVENT_STOP);
 457
 458         if (i2c_debug > 2)
 459                 dev_dbg(&i2c->adap.dev, "ISR: SSD (Slave Stop) acked\n");
 460
 461         /*
 462          * If we have a master-mode message waiting,
 463          * kick it off now that the slave has completed.
 464          */
 465         if (i2c->msg)
 466                 i2c_pxa_master_complete(i2c, I2C_RETRY);
 467 }
 468 #else
 469 static void i2c_pxa_slave_txempty(struct pxa_i2c *i2c, u32 isr)
 470 {
 471         if (isr & ISR_BED) {
 472                 /* what should we do here? */
 473         } else {
 474                 writel(0, _IDBR(i2c));
 475                 writel(readl(_ICR(i2c)) | ICR_TB, _ICR(i2c));
 476         }
 477 }
 478
 479 static void i2c_pxa_slave_rxfull(struct pxa_i2c *i2c, u32 isr)
 480 {
 481         writel(readl(_ICR(i2c)) | ICR_TB | ICR_ACKNAK, _ICR(i2c));
 482 }
 483
 484 static void i2c_pxa_slave_start(struct pxa_i2c *i2c, u32 isr)
 485 {
 486         int timeout;
 487
 488         /*
 489          * slave could interrupt in the middle of us generating a
 490          * start condition... if this happens, we'd better back off
 491          * and stop holding the poor thing up
 492          */
 493         writel(readl(_ICR(i2c)) & ~(ICR_START|ICR_STOP), _ICR(i2c));
 494         writel(readl(_ICR(i2c)) | ICR_TB | ICR_ACKNAK, _ICR(i2c));
 495
 496         timeout = 0x10000;
 497
 498         while (1) {
 499                 if ((readl(_IBMR(i2c)) & 2) == 2)
 500                         break;
 501
 502                 timeout--;
 503
 504                 if (timeout <= 0) {
 505                         dev_err(&i2c->adap.dev, "timeout waiting for SCL high\n");
 506                         break;
 507                 }
 508         }
 509
 510         writel(readl(_ICR(i2c)) & ~ICR_SCLE, _ICR(i2c));
 511 }
 512
 513 static void i2c_pxa_slave_stop(struct pxa_i2c *i2c)
 514 {
 515         if (i2c->msg)
 516                 i2c_pxa_master_complete(i2c, I2C_RETRY);
 517 }
 518 #endif
 519
 520 /*
 521  * PXA I2C Master mode
 522  */
 523
 524 static inline unsigned int i2c_pxa_addr_byte(struct i2c_msg *msg)
 525 {
 526         unsigned int addr = (msg->addr & 0x7f) << 1;
 527
 528         if (msg->flags & I2C_M_RD)
 529                 addr |= 1;
 530
 531         return addr;
 532 }
 533
 534 static inline void i2c_pxa_start_message(struct pxa_i2c *i2c)
 535 {
 536         u32 icr;
 537
 538         /*
 539          * Step 1: target slave address into IDBR
 540          */
 541         writel(i2c_pxa_addr_byte(i2c->msg), _IDBR(i2c));
 542
 543         /*
 544          * Step 2: initiate the write.
 545          */
 546         icr = readl(_ICR(i2c)) & ~(ICR_STOP | ICR_ALDIE);
 547         writel(icr | ICR_START | ICR_TB, _ICR(i2c));
 548 }
 549
 550 static inline void i2c_pxa_stop_message(struct pxa_i2c *i2c)
 551 {
 552         u32 icr;
 553
 554         /*
 555          * Clear the STOP and ACK flags
 556          */
 557         icr = readl(_ICR(i2c));
 558         icr &= ~(ICR_STOP | ICR_ACKNAK);
 559         writel(icr, _ICR(i2c));
 560 }
 561
 562 static int i2c_pxa_pio_set_master(struct pxa_i2c *i2c)
 563 {
 564         /* make timeout the same as for interrupt based functions */
 565         long timeout = 2 * DEF_TIMEOUT;
 566
 567         /*
 568          * Wait for the bus to become free.
 569          */
 570         while (timeout-- && readl(_ISR(i2c)) & (ISR_IBB | ISR_UB)) {
 571                 udelay(1000);
 572                 show_state(i2c);
 573         }
 574
 575         if (timeout <= 0) {
 576                 show_state(i2c);
 577                 dev_err(&i2c->adap.dev,
 578                         "i2c_pxa: timeout waiting for bus free\n");
 579                 return I2C_RETRY;
 580         }
 581
 582         /*
 583          * Set master mode.
 584          */
 585         writel(readl(_ICR(i2c)) | ICR_SCLE, _ICR(i2c));
 586
 587         return 0;
 588 }
 589
 590 static int i2c_pxa_do_pio_xfer(struct pxa_i2c *i2c,
 591                                struct i2c_msg *msg, int num)
 592 {
 593         unsigned long timeout = 500000; /* 5 seconds */
 594         int ret = 0;
 595
 596         ret = i2c_pxa_pio_set_master(i2c);
 597         if (ret)
 598                 goto out;
 599
 600         i2c->msg = msg;
 601         i2c->msg_num = num;
 602         i2c->msg_idx = 0;
 603         i2c->msg_ptr = 0;
 604         i2c->irqlogidx = 0;
 605
 606         i2c_pxa_start_message(i2c);
 607
 608         while (timeout-- && i2c->msg_num > 0) {
 609                 i2c_pxa_handler(0, i2c);
 610                 udelay(10);
 611         }
 612
 613         i2c_pxa_stop_message(i2c);
 614
 615         /*
 616          * We place the return code in i2c->msg_idx.
 617          */
 618         ret = i2c->msg_idx;
 619
 620 out:
 621         if (timeout == 0)
 622                 i2c_pxa_scream_blue_murder(i2c, "timeout");
 623
 624         return ret;
 625 }
 626
 627 /*
 628  * We are protected by the adapter bus mutex.
 629  */
 630 static int i2c_pxa_do_xfer(struct pxa_i2c *i2c, struct i2c_msg *msg, int num)
 631 {
 632         long timeout;
 633         int ret;
 634
 635         /*
 636          * Wait for the bus to become free.
 637          */
 638         ret = i2c_pxa_wait_bus_not_busy(i2c);
 639         if (ret) {
 640                 dev_err(&i2c->adap.dev, "i2c_pxa: timeout waiting for bus free\n");
 641                 goto out;
 642         }
 643
 644         /*
 645          * Set master mode.
 646          */
 647         ret = i2c_pxa_set_master(i2c);
 648         if (ret) {
 649                 dev_err(&i2c->adap.dev, "i2c_pxa_set_master: error %d\n", ret);
 650                 goto out;
 651         }
 652
 653         spin_lock_irq(&i2c->lock);
 654
 655         i2c->msg = msg;
 656         i2c->msg_num = num;
 657         i2c->msg_idx = 0;
 658         i2c->msg_ptr = 0;
 659         i2c->irqlogidx = 0;
 660
 661         i2c_pxa_start_message(i2c);
 662
 663         spin_unlock_irq(&i2c->lock);
 664
 665         /*
 666          * The rest of the processing occurs in the interrupt handler.
 667          */
 668         timeout = wait_event_timeout(i2c->wait, i2c->msg_num == 0, HZ * 5);
 669         i2c_pxa_stop_message(i2c);
 670
 671         /*
 672          * We place the return code in i2c->msg_idx.
 673          */
 674         ret = i2c->msg_idx;
 675
 676         if (timeout == 0)
 677                 i2c_pxa_scream_blue_murder(i2c, "timeout");
 678
 679  out:
 680         return ret;
 681 }
 682
 683 static int i2c_pxa_pio_xfer(struct i2c_adapter *adap,
 684                             struct i2c_msg msgs[], int num)
 685 {
 686         struct pxa_i2c *i2c = adap->algo_data;
 687         int ret, i;
 688
 689         /* If the I2C controller is disabled we need to reset it
 690           (probably due to a suspend/resume destroying state). We do
 691           this here as we can then avoid worrying about resuming the
 692           controller before its users. */
 693         if (!(readl(_ICR(i2c)) & ICR_IUE))
 694                 i2c_pxa_reset(i2c);
 695
 696         for (i = adap->retries; i >= 0; i--) {
 697                 ret = i2c_pxa_do_pio_xfer(i2c, msgs, num);
 698                 if (ret != I2C_RETRY)
 699                         goto out;
 700
 701                 if (i2c_debug)
 702                         dev_dbg(&adap->dev, "Retrying transmission\n");
 703                 udelay(100);
 704         }
 705         i2c_pxa_scream_blue_murder(i2c, "exhausted retries");
 706         ret = -EREMOTEIO;
 707  out:
 708         i2c_pxa_set_slave(i2c, ret);
 709         return ret;
 710 }
 711
 712 /*
 713  * i2c_pxa_master_complete - complete the message and wake up.
 714  */
 715 static void i2c_pxa_master_complete(struct pxa_i2c *i2c, int ret)
 716 {
 717         i2c->msg_ptr = 0;
 718         i2c->msg = NULL;
 719         i2c->msg_idx ++;
 720         i2c->msg_num = 0;
 721         if (ret)
 722                 i2c->msg_idx = ret;
 723         if (!i2c->use_pio)
 724                 wake_up(&i2c->wait);
 725 }
 726
 727 static void i2c_pxa_irq_txempty(struct pxa_i2c *i2c, u32 isr)
 728 {
 729         u32 icr = readl(_ICR(i2c)) & ~(ICR_START|ICR_STOP|ICR_ACKNAK|ICR_TB);
 730
 731  again:
 732         /*
 733          * If ISR_ALD is set, we lost arbitration.
 734          */
 735         if (isr & ISR_ALD) {
 736                 /*
 737                  * Do we need to do anything here?  The PXA docs
 738                  * are vague about what happens.
 739                  */
 740                 i2c_pxa_scream_blue_murder(i2c, "ALD set");
 741
 742                 /*
 743                  * We ignore this error.  We seem to see spurious ALDs
 744                  * for seemingly no reason.  If we handle them as I think
 745                  * they should, we end up causing an I2C error, which
 746                  * is painful for some systems.
 747                  */
 748                 return; /* ignore */
 749         }
 750
 751         if (isr & ISR_BED) {
 752                 int ret = BUS_ERROR;
 753
 754                 /*
 755                  * I2C bus error - either the device NAK'd us, or
 756                  * something more serious happened.  If we were NAK'd
 757                  * on the initial address phase, we can retry.
 758                  */
 759                 if (isr & ISR_ACKNAK) {
 760                         if (i2c->msg_ptr == 0 && i2c->msg_idx == 0)
 761                                 ret = I2C_RETRY;
 762                         else
 763                                 ret = XFER_NAKED;
 764                 }
 765                 i2c_pxa_master_complete(i2c, ret);
 766         } else if (isr & ISR_RWM) {
 767                 /*
 768                  * Read mode.  We have just sent the address byte, and
 769                  * now we must initiate the transfer.
 770                  */
 771                 if (i2c->msg_ptr == i2c->msg->len - 1 &&
 772                     i2c->msg_idx == i2c->msg_num - 1)
 773                         icr |= ICR_STOP | ICR_ACKNAK;
 774
 775                 icr |= ICR_ALDIE | ICR_TB;
 776         } else if (i2c->msg_ptr < i2c->msg->len) {
 777                 /*
 778                  * Write mode.  Write the next data byte.
 779                  */
 780                 writel(i2c->msg->buf[i2c->msg_ptr++], _IDBR(i2c));
 781
 782                 icr |= ICR_ALDIE | ICR_TB;
 783
 784                 /*
 785                  * If this is the last byte of the last message, send
 786                  * a STOP.
 787                  */
 788                 if (i2c->msg_ptr == i2c->msg->len &&
 789                     i2c->msg_idx == i2c->msg_num - 1)
 790                         icr |= ICR_STOP;
 791         } else if (i2c->msg_idx < i2c->msg_num - 1) {
 792                 /*
 793                  * Next segment of the message.
 794                  */
 795                 i2c->msg_ptr = 0;
 796                 i2c->msg_idx ++;
 797                 i2c->msg++;
 798
 799                 /*
 800                  * If we aren't doing a repeated start and address,
 801                  * go back and try to send the next byte.  Note that
 802                  * we do not support switching the R/W direction here.
 803                  */
 804                 if (i2c->msg->flags & I2C_M_NOSTART)
 805                         goto again;
 806
 807                 /*
 808                  * Write the next address.
 809                  */
 810                 writel(i2c_pxa_addr_byte(i2c->msg), _IDBR(i2c));
 811
 812                 /*
 813                  * And trigger a repeated start, and send the byte.
 814                  */
 815                 icr &= ~ICR_ALDIE;
 816                 icr |= ICR_START | ICR_TB;
 817         } else {
 818                 if (i2c->msg->len == 0) {
 819                         /*
 820                          * Device probes have a message length of zero
 821                          * and need the bus to be reset before it can
 822                          * be used again.
 823                          */
 824                         i2c_pxa_reset(i2c);
 825                 }
 826                 i2c_pxa_master_complete(i2c, 0);
 827         }
 828
 829         i2c->icrlog[i2c->irqlogidx-1] = icr;
 830
 831         writel(icr, _ICR(i2c));
 832         show_state(i2c);
 833 }
 834
 835 static void i2c_pxa_irq_rxfull(struct pxa_i2c *i2c, u32 isr)
 836 {
 837         u32 icr = readl(_ICR(i2c)) & ~(ICR_START|ICR_STOP|ICR_ACKNAK|ICR_TB);
 838
 839         /*
 840          * Read the byte.
 841          */
 842         i2c->msg->buf[i2c->msg_ptr++] = readl(_IDBR(i2c));
 843
 844         if (i2c->msg_ptr < i2c->msg->len) {
 845                 /*
 846                  * If this is the last byte of the last
 847                  * message, send a STOP.
 848                  */
 849                 if (i2c->msg_ptr == i2c->msg->len - 1)
 850                         icr |= ICR_STOP | ICR_ACKNAK;
 851
 852                 icr |= ICR_ALDIE | ICR_TB;
 853         } else {
 854                 i2c_pxa_master_complete(i2c, 0);
 855         }
 856
 857         i2c->icrlog[i2c->irqlogidx-1] = icr;
 858
 859         writel(icr, _ICR(i2c));
 860 }
 861
 862 static irqreturn_t i2c_pxa_handler(int this_irq, void *dev_id)
 863 {
 864         struct pxa_i2c *i2c = dev_id;
 865         u32 isr = readl(_ISR(i2c));
 866
 867         if (i2c_debug > 2 && 0) {
 868                 dev_dbg(&i2c->adap.dev, "%s: ISR=%08x, ICR=%08x, IBMR=%02x\n",
 869                         __func__, isr, readl(_ICR(i2c)), readl(_IBMR(i2c)));
 870                 decode_ISR(isr);
 871         }
 872
 873         if (i2c->irqlogidx < ARRAY_SIZE(i2c->isrlog))
 874                 i2c->isrlog[i2c->irqlogidx++] = isr;
 875
 876         show_state(i2c);
 877
 878         /*
 879          * Always clear all pending IRQs.
 880          */
 881         writel(isr & (ISR_SSD|ISR_ALD|ISR_ITE|ISR_IRF|ISR_SAD|ISR_BED), _ISR(i2c));
 882
 883         if (isr & ISR_SAD)
 884                 i2c_pxa_slave_start(i2c, isr);
 885         if (isr & ISR_SSD)
 886                 i2c_pxa_slave_stop(i2c);
 887
 888         if (i2c_pxa_is_slavemode(i2c)) {
 889                 if (isr & ISR_ITE)
 890                         i2c_pxa_slave_txempty(i2c, isr);
 891                 if (isr & ISR_IRF)
 892                         i2c_pxa_slave_rxfull(i2c, isr);
 893         } else if (i2c->msg) {
 894                 if (isr & ISR_ITE)
 895                         i2c_pxa_irq_txempty(i2c, isr);
 896                 if (isr & ISR_IRF)
 897                         i2c_pxa_irq_rxfull(i2c, isr);
 898         } else {
 899                 i2c_pxa_scream_blue_murder(i2c, "spurious irq");
 900         }
 901
 902         return IRQ_HANDLED;
 903 }
 904
 905
 906 static int i2c_pxa_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
 907 {
 908         struct pxa_i2c *i2c = adap->algo_data;
 909         int ret, i;
 910
 911         /* If the I2C controller is disabled we need to reset it (probably due
 912            to a suspend/resume destroying state). We do this here as we can then
 913            avoid worrying about resuming the controller before its users. */
 914         if (!(readl(_ICR(i2c)) & ICR_IUE))
 915                 i2c_pxa_reset(i2c);
 916
 917         for (i = adap->retries; i >= 0; i--) {
 918                 ret = i2c_pxa_do_xfer(i2c, msgs, num);
 919                 if (ret != I2C_RETRY)
 920                         goto out;
 921
 922                 if (i2c_debug)
 923                         dev_dbg(&adap->dev, "Retrying transmission\n");
 924                 udelay(100);
 925         }
 926         i2c_pxa_scream_blue_murder(i2c, "exhausted retries");
 927         ret = -EREMOTEIO;
 928  out:
 929         i2c_pxa_set_slave(i2c, ret);
 930         return ret;
 931 }
 932
 933 static u32 i2c_pxa_functionality(struct i2c_adapter *adap)
 934 {
 935         return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
 936 }
 937
 938 static const struct i2c_algorithm i2c_pxa_algorithm = {
 939         .master_xfer    = i2c_pxa_xfer,
 940         .functionality  = i2c_pxa_functionality,
 941 };
 942
 943 static const struct i2c_algorithm i2c_pxa_pio_algorithm = {
 944         .master_xfer    = i2c_pxa_pio_xfer,
 945         .functionality  = i2c_pxa_functionality,
 946 };
 947
 948 #define res_len(r)              ((r)->end - (r)->start + 1)
 949 static int i2c_pxa_probe(struct platform_device *dev)
 950 {
 951         struct pxa_i2c *i2c;
 952         struct resource *res;
 953         struct i2c_pxa_platform_data *plat = dev->dev.platform_data;
 954         int ret;
 955         int irq;
 956
 957         res = platform_get_resource(dev, IORESOURCE_MEM, 0);
 958         irq = platform_get_irq(dev, 0);
 959         if (res == NULL || irq < 0)
 960                 return -ENODEV;
 961
 962         if (!request_mem_region(res->start, res_len(res), res->name))
 963                 return -ENOMEM;
 964
 965         i2c = kzalloc(sizeof(struct pxa_i2c), GFP_KERNEL);
 966         if (!i2c) {
 967                 ret = -ENOMEM;
 968                 goto emalloc;
 969         }
 970
 971         i2c->adap.owner   = THIS_MODULE;
 972         i2c->adap.retries = 5;
 973
 974         spin_lock_init(&i2c->lock);
 975         init_waitqueue_head(&i2c->wait);
 976
 977         /*
 978          * If "dev->id" is negative we consider it as zero.
 979          * The reason to do so is to avoid sysfs names that only make
 980          * sense when there are multiple adapters.
 981          */
 982         i2c->adap.nr = dev->id != -1 ? dev->id : 0;
 983         snprintf(i2c->adap.name, sizeof(i2c->adap.name), "pxa_i2c-i2c.%u",
 984                  i2c->adap.nr);
 985
 986         i2c->clk = clk_get(&dev->dev, "I2CCLK");
 987         if (IS_ERR(i2c->clk)) {
 988                 ret = PTR_ERR(i2c->clk);
 989                 goto eclk;
 990         }
 991
 992         i2c->reg_base = ioremap(res->start, res_len(res));
 993         if (!i2c->reg_base) {
 994                 ret = -EIO;
 995                 goto eremap;
 996         }
 997
 998         i2c->iobase = res->start;
 999         i2c->iosize = res_len(res);
1000
1001         i2c->irq = irq;
1002
1003         i2c->slave_addr = I2C_PXA_SLAVE_ADDR;
1004
1005 #ifdef CONFIG_I2C_PXA_SLAVE
1006         if (plat) {
1007                 i2c->slave_addr = plat->slave_addr;
1008                 i2c->slave = plat->slave;
1009         }
1010 #endif
1011
1012         clk_enable(i2c->clk);
1013
1014         if (plat) {
1015                 i2c->adap.class = plat->class;
1016                 i2c->use_pio = plat->use_pio;
1017         }
1018
1019         if (i2c->use_pio) {
1020                 i2c->adap.algo = &i2c_pxa_pio_algorithm;
1021         } else {
1022                 i2c->adap.algo = &i2c_pxa_algorithm;
1023                 ret = request_irq(irq, i2c_pxa_handler, IRQF_DISABLED,
1024                                   i2c->adap.name, i2c);
1025                 if (ret)
1026                         goto ereqirq;
1027         }
1028
1029         i2c_pxa_reset(i2c);
1030
1031         i2c->adap.algo_data = i2c;
1032         i2c->adap.dev.parent = &dev->dev;
1033
1034         ret = i2c_add_numbered_adapter(&i2c->adap);
1035         if (ret < 0) {
1036                 printk(KERN_INFO "I2C: Failed to add bus\n");
1037                 goto eadapt;
1038         }
1039
1040         platform_set_drvdata(dev, i2c);
1041
1042 #ifdef CONFIG_I2C_PXA_SLAVE
1043         printk(KERN_INFO "I2C: %s: PXA I2C adapter, slave address %d\n",
1044                i2c->adap.dev.bus_id, i2c->slave_addr);
1045 #else
1046         printk(KERN_INFO "I2C: %s: PXA I2C adapter\n",
1047                i2c->adap.dev.bus_id);
1048 #endif
1049         return 0;
1050
1051 eadapt:
1052         if (!i2c->use_pio)
1053                 free_irq(irq, i2c);
1054 ereqirq:
1055         clk_disable(i2c->clk);
1056         iounmap(i2c->reg_base);
1057 eremap:
1058         clk_put(i2c->clk);
1059 eclk:
1060         kfree(i2c);
1061 emalloc:
1062         release_mem_region(res->start, res_len(res));
1063         return ret;
1064 }
1065
1066 static int __exit i2c_pxa_remove(struct platform_device *dev)
1067 {
1068         struct pxa_i2c *i2c = platform_get_drvdata(dev);
1069
1070         platform_set_drvdata(dev, NULL);
1071
1072         i2c_del_adapter(&i2c->adap);
1073         if (!i2c->use_pio)
1074                 free_irq(i2c->irq, i2c);
1075
1076         clk_disable(i2c->clk);
1077         clk_put(i2c->clk);
1078
1079         iounmap(i2c->reg_base);
1080         release_mem_region(i2c->iobase, i2c->iosize);
1081         kfree(i2c);
1082
1083         return 0;
1084 }
1085
1086 static struct platform_driver i2c_pxa_driver = {
1087         .probe          = i2c_pxa_probe,
1088         .remove         = __exit_p(i2c_pxa_remove),
1089         .driver         = {
1090                 .name   = "pxa2xx-i2c",
1091                 .owner  = THIS_MODULE,
1092         },
1093 };
1094
1095 static int __init i2c_adap_pxa_init(void)
1096 {
1097         return platform_driver_register(&i2c_pxa_driver);
1098 }
1099
1100 static void __exit i2c_adap_pxa_exit(void)
1101 {
1102         platform_driver_unregister(&i2c_pxa_driver);
1103 }
1104
1105 MODULE_LICENSE("GPL");
1106 MODULE_ALIAS("platform:pxa2xx-i2c");
1107
1108 module_init(i2c_adap_pxa_init);
1109 module_exit(i2c_adap_pxa_exit);