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