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   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 static void decode_ICR(unsigned int val)
 142 {
 143         decode_bits(KERN_DEBUG "ICR", icr_bits, ARRAY_SIZE(icr_bits), val);
 144         printk("\n");
 145 }
 146
 147 static unsigned int i2c_debug = DEBUG;
 148
 149 static void i2c_pxa_show_state(struct pxa_i2c *i2c, int lno, const char *fname)
 150 {
 151         dev_dbg(&i2c->adap.dev, "state:%s:%d: ISR=%08x, ICR=%08x, IBMR=%02x\n", fname, lno,
 152                 readl(_ISR(i2c)), readl(_ICR(i2c)), readl(_IBMR(i2c)));
 153 }
 154
 155 #define show_state(i2c) i2c_pxa_show_state(i2c, __LINE__, __FUNCTION__)
 156 #else
 157 #define i2c_debug       0
 158
 159 #define show_state(i2c) do { } while (0)
 160 #define decode_ISR(val) do { } while (0)
 161 #define decode_ICR(val) do { } while (0)
 162 #endif
 163
 164 #define eedbg(lvl, x...) do { if ((lvl) < 1) { printk(KERN_DEBUG "" x); } } while(0)
 165
 166 static void i2c_pxa_master_complete(struct pxa_i2c *i2c, int ret);
 167 static irqreturn_t i2c_pxa_handler(int this_irq, void *dev_id);
 168
 169 static void i2c_pxa_scream_blue_murder(struct pxa_i2c *i2c, const char *why)
 170 {
 171         unsigned int i;
 172         printk("i2c: error: %s\n", why);
 173         printk("i2c: msg_num: %d msg_idx: %d msg_ptr: %d\n",
 174                 i2c->msg_num, i2c->msg_idx, i2c->msg_ptr);
 175         printk("i2c: ICR: %08x ISR: %08x\n"
 176                "i2c: log: ", readl(_ICR(i2c)), readl(_ISR(i2c)));
 177         for (i = 0; i < i2c->irqlogidx; i++)
 178                 printk("[%08x:%08x] ", i2c->isrlog[i], i2c->icrlog[i]);
 179         printk("\n");
 180 }
 181
 182 static inline int i2c_pxa_is_slavemode(struct pxa_i2c *i2c)
 183 {
 184         return !(readl(_ICR(i2c)) & ICR_SCLE);
 185 }
 186
 187 static void i2c_pxa_abort(struct pxa_i2c *i2c)
 188 {
 189         unsigned long timeout = jiffies + HZ/4;
 190
 191         if (i2c_pxa_is_slavemode(i2c)) {
 192                 dev_dbg(&i2c->adap.dev, "%s: called in slave mode\n", __func__);
 193                 return;
 194         }
 195
 196         while (time_before(jiffies, timeout) && (readl(_IBMR(i2c)) & 0x1) == 0) {
 197                 unsigned long icr = readl(_ICR(i2c));
 198
 199                 icr &= ~ICR_START;
 200                 icr |= ICR_ACKNAK | ICR_STOP | ICR_TB;
 201
 202                 writel(icr, _ICR(i2c));
 203
 204                 show_state(i2c);
 205
 206                 msleep(1);
 207         }
 208
 209         writel(readl(_ICR(i2c)) & ~(ICR_MA | ICR_START | ICR_STOP),
 210                _ICR(i2c));
 211 }
 212
 213 static int i2c_pxa_wait_bus_not_busy(struct pxa_i2c *i2c)
 214 {
 215         int timeout = DEF_TIMEOUT;
 216
 217         while (timeout-- && readl(_ISR(i2c)) & (ISR_IBB | ISR_UB)) {
 218                 if ((readl(_ISR(i2c)) & ISR_SAD) != 0)
 219                         timeout += 4;
 220
 221                 msleep(2);
 222                 show_state(i2c);
 223         }
 224
 225         if (timeout <= 0)
 226                 show_state(i2c);
 227
 228         return timeout <= 0 ? I2C_RETRY : 0;
 229 }
 230
 231 static int i2c_pxa_wait_master(struct pxa_i2c *i2c)
 232 {
 233         unsigned long timeout = jiffies + HZ*4;
 234
 235         while (time_before(jiffies, timeout)) {
 236                 if (i2c_debug > 1)
 237                         dev_dbg(&i2c->adap.dev, "%s: %ld: ISR=%08x, ICR=%08x, IBMR=%02x\n",
 238                                 __func__, (long)jiffies, readl(_ISR(i2c)), readl(_ICR(i2c)), readl(_IBMR(i2c)));
 239
 240                 if (readl(_ISR(i2c)) & ISR_SAD) {
 241                         if (i2c_debug > 0)
 242                                 dev_dbg(&i2c->adap.dev, "%s: Slave detected\n", __func__);
 243                         goto out;
 244                 }
 245
 246                 /* wait for unit and bus being not busy, and we also do a
 247                  * quick check of the i2c lines themselves to ensure they've
 248                  * gone high...
 249                  */
 250                 if ((readl(_ISR(i2c)) & (ISR_UB | ISR_IBB)) == 0 && readl(_IBMR(i2c)) == 3) {
 251                         if (i2c_debug > 0)
 252                                 dev_dbg(&i2c->adap.dev, "%s: done\n", __func__);
 253                         return 1;
 254                 }
 255
 256                 msleep(1);
 257         }
 258
 259         if (i2c_debug > 0)
 260                 dev_dbg(&i2c->adap.dev, "%s: did not free\n", __func__);
 261  out:
 262         return 0;
 263 }
 264
 265 static int i2c_pxa_set_master(struct pxa_i2c *i2c)
 266 {
 267         if (i2c_debug)
 268                 dev_dbg(&i2c->adap.dev, "setting to bus master\n");
 269
 270         if ((readl(_ISR(i2c)) & (ISR_UB | ISR_IBB)) != 0) {
 271                 dev_dbg(&i2c->adap.dev, "%s: unit is busy\n", __func__);
 272                 if (!i2c_pxa_wait_master(i2c)) {
 273                         dev_dbg(&i2c->adap.dev, "%s: error: unit busy\n", __func__);
 274                         return I2C_RETRY;
 275                 }
 276         }
 277
 278         writel(readl(_ICR(i2c)) | ICR_SCLE, _ICR(i2c));
 279         return 0;
 280 }
 281
 282 #ifdef CONFIG_I2C_PXA_SLAVE
 283 static int i2c_pxa_wait_slave(struct pxa_i2c *i2c)
 284 {
 285         unsigned long timeout = jiffies + HZ*1;
 286
 287         /* wait for stop */
 288
 289         show_state(i2c);
 290
 291         while (time_before(jiffies, timeout)) {
 292                 if (i2c_debug > 1)
 293                         dev_dbg(&i2c->adap.dev, "%s: %ld: ISR=%08x, ICR=%08x, IBMR=%02x\n",
 294                                 __func__, (long)jiffies, readl(_ISR(i2c)), readl(_ICR(i2c)), readl(_IBMR(i2c)));
 295
 296                 if ((readl(_ISR(i2c)) & (ISR_UB|ISR_IBB)) == 0 ||
 297                     (readl(_ISR(i2c)) & ISR_SAD) != 0 ||
 298                     (readl(_ICR(i2c)) & ICR_SCLE) == 0) {
 299                         if (i2c_debug > 1)
 300                                 dev_dbg(&i2c->adap.dev, "%s: done\n", __func__);
 301                         return 1;
 302                 }
 303
 304                 msleep(1);
 305         }
 306
 307         if (i2c_debug > 0)
 308                 dev_dbg(&i2c->adap.dev, "%s: did not free\n", __func__);
 309         return 0;
 310 }
 311
 312 /*
 313  * clear the hold on the bus, and take of anything else
 314  * that has been configured
 315  */
 316 static void i2c_pxa_set_slave(struct pxa_i2c *i2c, int errcode)
 317 {
 318         show_state(i2c);
 319
 320         if (errcode < 0) {
 321                 udelay(100);   /* simple delay */
 322         } else {
 323                 /* we need to wait for the stop condition to end */
 324
 325                 /* if we where in stop, then clear... */
 326                 if (readl(_ICR(i2c)) & ICR_STOP) {
 327                         udelay(100);
 328                         writel(readl(_ICR(i2c)) & ~ICR_STOP, _ICR(i2c));
 329                 }
 330
 331                 if (!i2c_pxa_wait_slave(i2c)) {
 332                         dev_err(&i2c->adap.dev, "%s: wait timedout\n",
 333                                 __func__);
 334                         return;
 335                 }
 336         }
 337
 338         writel(readl(_ICR(i2c)) & ~(ICR_STOP|ICR_ACKNAK|ICR_MA), _ICR(i2c));
 339         writel(readl(_ICR(i2c)) & ~ICR_SCLE, _ICR(i2c));
 340
 341         if (i2c_debug) {
 342                 dev_dbg(&i2c->adap.dev, "ICR now %08x, ISR %08x\n", readl(_ICR(i2c)), readl(_ISR(i2c)));
 343                 decode_ICR(readl(_ICR(i2c)));
 344         }
 345 }
 346 #else
 347 #define i2c_pxa_set_slave(i2c, err)     do { } while (0)
 348 #endif
 349
 350 static void i2c_pxa_reset(struct pxa_i2c *i2c)
 351 {
 352         pr_debug("Resetting I2C Controller Unit\n");
 353
 354         /* abort any transfer currently under way */
 355         i2c_pxa_abort(i2c);
 356
 357         /* reset according to 9.8 */
 358         writel(ICR_UR, _ICR(i2c));
 359         writel(I2C_ISR_INIT, _ISR(i2c));
 360         writel(readl(_ICR(i2c)) & ~ICR_UR, _ICR(i2c));
 361
 362         writel(i2c->slave_addr, _ISAR(i2c));
 363
 364         /* set control register values */
 365         writel(I2C_ICR_INIT, _ICR(i2c));
 366
 367 #ifdef CONFIG_I2C_PXA_SLAVE
 368         dev_info(&i2c->adap.dev, "Enabling slave mode\n");
 369         writel(readl(_ICR(i2c)) | ICR_SADIE | ICR_ALDIE | ICR_SSDIE, _ICR(i2c));
 370 #endif
 371
 372         i2c_pxa_set_slave(i2c, 0);
 373
 374         /* enable unit */
 375         writel(readl(_ICR(i2c)) | ICR_IUE, _ICR(i2c));
 376         udelay(100);
 377 }
 378
 379
 380 #ifdef CONFIG_I2C_PXA_SLAVE
 381 /*
 382  * PXA I2C Slave mode
 383  */
 384
 385 static void i2c_pxa_slave_txempty(struct pxa_i2c *i2c, u32 isr)
 386 {
 387         if (isr & ISR_BED) {
 388                 /* what should we do here? */
 389         } else {
 390                 int ret = 0;
 391
 392                 if (i2c->slave != NULL)
 393                         ret = i2c->slave->read(i2c->slave->data);
 394
 395                 writel(ret, _IDBR(i2c));
 396                 writel(readl(_ICR(i2c)) | ICR_TB, _ICR(i2c));   /* allow next byte */
 397         }
 398 }
 399
 400 static void i2c_pxa_slave_rxfull(struct pxa_i2c *i2c, u32 isr)
 401 {
 402         unsigned int byte = readl(_IDBR(i2c));
 403
 404         if (i2c->slave != NULL)
 405                 i2c->slave->write(i2c->slave->data, byte);
 406
 407         writel(readl(_ICR(i2c)) | ICR_TB, _ICR(i2c));
 408 }
 409
 410 static void i2c_pxa_slave_start(struct pxa_i2c *i2c, u32 isr)
 411 {
 412         int timeout;
 413
 414         if (i2c_debug > 0)
 415                 dev_dbg(&i2c->adap.dev, "SAD, mode is slave-%cx\n",
 416                        (isr & ISR_RWM) ? 'r' : 't');
 417
 418         if (i2c->slave != NULL)
 419                 i2c->slave->event(i2c->slave->data,
 420                                  (isr & ISR_RWM) ? I2C_SLAVE_EVENT_START_READ : I2C_SLAVE_EVENT_START_WRITE);
 421
 422         /*
 423          * slave could interrupt in the middle of us generating a
 424          * start condition... if this happens, we'd better back off
 425          * and stop holding the poor thing up
 426          */
 427         writel(readl(_ICR(i2c)) & ~(ICR_START|ICR_STOP), _ICR(i2c));
 428         writel(readl(_ICR(i2c)) | ICR_TB, _ICR(i2c));
 429
 430         timeout = 0x10000;
 431
 432         while (1) {
 433                 if ((readl(_IBMR(i2c)) & 2) == 2)
 434                         break;
 435
 436                 timeout--;
 437
 438                 if (timeout <= 0) {
 439                         dev_err(&i2c->adap.dev, "timeout waiting for SCL high\n");
 440                         break;
 441                 }
 442         }
 443
 444         writel(readl(_ICR(i2c)) & ~ICR_SCLE, _ICR(i2c));
 445 }
 446
 447 static void i2c_pxa_slave_stop(struct pxa_i2c *i2c)
 448 {
 449         if (i2c_debug > 2)
 450                 dev_dbg(&i2c->adap.dev, "ISR: SSD (Slave Stop)\n");
 451
 452         if (i2c->slave != NULL)
 453                 i2c->slave->event(i2c->slave->data, I2C_SLAVE_EVENT_STOP);
 454
 455         if (i2c_debug > 2)
 456                 dev_dbg(&i2c->adap.dev, "ISR: SSD (Slave Stop) acked\n");
 457
 458         /*
 459          * If we have a master-mode message waiting,
 460          * kick it off now that the slave has completed.
 461          */
 462         if (i2c->msg)
 463                 i2c_pxa_master_complete(i2c, I2C_RETRY);
 464 }
 465 #else
 466 static void i2c_pxa_slave_txempty(struct pxa_i2c *i2c, u32 isr)
 467 {
 468         if (isr & ISR_BED) {
 469                 /* what should we do here? */
 470         } else {
 471                 writel(0, _IDBR(i2c));
 472                 writel(readl(_ICR(i2c)) | ICR_TB, _ICR(i2c));
 473         }
 474 }
 475
 476 static void i2c_pxa_slave_rxfull(struct pxa_i2c *i2c, u32 isr)
 477 {
 478         writel(readl(_ICR(i2c)) | ICR_TB | ICR_ACKNAK, _ICR(i2c));
 479 }
 480
 481 static void i2c_pxa_slave_start(struct pxa_i2c *i2c, u32 isr)
 482 {
 483         int timeout;
 484
 485         /*
 486          * slave could interrupt in the middle of us generating a
 487          * start condition... if this happens, we'd better back off
 488          * and stop holding the poor thing up
 489          */
 490         writel(readl(_ICR(i2c)) & ~(ICR_START|ICR_STOP), _ICR(i2c));
 491         writel(readl(_ICR(i2c)) | ICR_TB | ICR_ACKNAK, _ICR(i2c));
 492
 493         timeout = 0x10000;
 494
 495         while (1) {
 496                 if ((readl(_IBMR(i2c)) & 2) == 2)
 497                         break;
 498
 499                 timeout--;
 500
 501                 if (timeout <= 0) {
 502                         dev_err(&i2c->adap.dev, "timeout waiting for SCL high\n");
 503                         break;
 504                 }
 505         }
 506
 507         writel(readl(_ICR(i2c)) & ~ICR_SCLE, _ICR(i2c));
 508 }
 509
 510 static void i2c_pxa_slave_stop(struct pxa_i2c *i2c)
 511 {
 512         if (i2c->msg)
 513                 i2c_pxa_master_complete(i2c, I2C_RETRY);
 514 }
 515 #endif
 516
 517 /*
 518  * PXA I2C Master mode
 519  */
 520
 521 static inline unsigned int i2c_pxa_addr_byte(struct i2c_msg *msg)
 522 {
 523         unsigned int addr = (msg->addr & 0x7f) << 1;
 524
 525         if (msg->flags & I2C_M_RD)
 526                 addr |= 1;
 527
 528         return addr;
 529 }
 530
 531 static inline void i2c_pxa_start_message(struct pxa_i2c *i2c)
 532 {
 533         u32 icr;
 534
 535         /*
 536          * Step 1: target slave address into IDBR
 537          */
 538         writel(i2c_pxa_addr_byte(i2c->msg), _IDBR(i2c));
 539
 540         /*
 541          * Step 2: initiate the write.
 542          */
 543         icr = readl(_ICR(i2c)) & ~(ICR_STOP | ICR_ALDIE);
 544         writel(icr | ICR_START | ICR_TB, _ICR(i2c));
 545 }
 546
 547 static inline void i2c_pxa_stop_message(struct pxa_i2c *i2c)
 548 {
 549         u32 icr;
 550
 551         /*
 552          * Clear the STOP and ACK flags
 553          */
 554         icr = readl(_ICR(i2c));
 555         icr &= ~(ICR_STOP | ICR_ACKNAK);
 556         writel(icr, _ICR(i2c));
 557 }
 558
 559 static int i2c_pxa_pio_set_master(struct pxa_i2c *i2c)
 560 {
 561         /* make timeout the same as for interrupt based functions */
 562         long timeout = 2 * DEF_TIMEOUT;
 563
 564         /*
 565          * Wait for the bus to become free.
 566          */
 567         while (timeout-- && readl(_ISR(i2c)) & (ISR_IBB | ISR_UB)) {
 568                 udelay(1000);
 569                 show_state(i2c);
 570         }
 571
 572         if (timeout <= 0) {
 573                 show_state(i2c);
 574                 dev_err(&i2c->adap.dev,
 575                         "i2c_pxa: timeout waiting for bus free\n");
 576                 return I2C_RETRY;
 577         }
 578
 579         /*
 580          * Set master mode.
 581          */
 582         writel(readl(_ICR(i2c)) | ICR_SCLE, _ICR(i2c));
 583
 584         return 0;
 585 }
 586
 587 static int i2c_pxa_do_pio_xfer(struct pxa_i2c *i2c,
 588                                struct i2c_msg *msg, int num)
 589 {
 590         unsigned long timeout = 500000; /* 5 seconds */
 591         int ret = 0;
 592
 593         ret = i2c_pxa_pio_set_master(i2c);
 594         if (ret)
 595                 goto out;
 596
 597         i2c->msg = msg;
 598         i2c->msg_num = num;
 599         i2c->msg_idx = 0;
 600         i2c->msg_ptr = 0;
 601         i2c->irqlogidx = 0;
 602
 603         i2c_pxa_start_message(i2c);
 604
 605         while (timeout-- && i2c->msg_num > 0) {
 606                 i2c_pxa_handler(0, i2c);
 607                 udelay(10);
 608         }
 609
 610         i2c_pxa_stop_message(i2c);
 611
 612         /*
 613          * We place the return code in i2c->msg_idx.
 614          */
 615         ret = i2c->msg_idx;
 616
 617 out:
 618         if (timeout == 0)
 619                 i2c_pxa_scream_blue_murder(i2c, "timeout");
 620
 621         return ret;
 622 }
 623
 624 /*
 625  * We are protected by the adapter bus mutex.
 626  */
 627 static int i2c_pxa_do_xfer(struct pxa_i2c *i2c, struct i2c_msg *msg, int num)
 628 {
 629         long timeout;
 630         int ret;
 631
 632         /*
 633          * Wait for the bus to become free.
 634          */
 635         ret = i2c_pxa_wait_bus_not_busy(i2c);
 636         if (ret) {
 637                 dev_err(&i2c->adap.dev, "i2c_pxa: timeout waiting for bus free\n");
 638                 goto out;
 639         }
 640
 641         /*
 642          * Set master mode.
 643          */
 644         ret = i2c_pxa_set_master(i2c);
 645         if (ret) {
 646                 dev_err(&i2c->adap.dev, "i2c_pxa_set_master: error %d\n", ret);
 647                 goto out;
 648         }
 649
 650         spin_lock_irq(&i2c->lock);
 651
 652         i2c->msg = msg;
 653         i2c->msg_num = num;
 654         i2c->msg_idx = 0;
 655         i2c->msg_ptr = 0;
 656         i2c->irqlogidx = 0;
 657
 658         i2c_pxa_start_message(i2c);
 659
 660         spin_unlock_irq(&i2c->lock);
 661
 662         /*
 663          * The rest of the processing occurs in the interrupt handler.
 664          */
 665         timeout = wait_event_timeout(i2c->wait, i2c->msg_num == 0, HZ * 5);
 666         i2c_pxa_stop_message(i2c);
 667
 668         /*
 669          * We place the return code in i2c->msg_idx.
 670          */
 671         ret = i2c->msg_idx;
 672
 673         if (timeout == 0)
 674                 i2c_pxa_scream_blue_murder(i2c, "timeout");
 675
 676  out:
 677         return ret;
 678 }
 679
 680 static int i2c_pxa_pio_xfer(struct i2c_adapter *adap,
 681                             struct i2c_msg msgs[], int num)
 682 {
 683         struct pxa_i2c *i2c = adap->algo_data;
 684         int ret, i;
 685
 686         /* If the I2C controller is disabled we need to reset it
 687           (probably due to a suspend/resume destroying state). We do
 688           this here as we can then avoid worrying about resuming the
 689           controller before its users. */
 690         if (!(readl(_ICR(i2c)) & ICR_IUE))
 691                 i2c_pxa_reset(i2c);
 692
 693         for (i = adap->retries; i >= 0; i--) {
 694                 ret = i2c_pxa_do_pio_xfer(i2c, msgs, num);
 695                 if (ret != I2C_RETRY)
 696                         goto out;
 697
 698                 if (i2c_debug)
 699                         dev_dbg(&adap->dev, "Retrying transmission\n");
 700                 udelay(100);
 701         }
 702         i2c_pxa_scream_blue_murder(i2c, "exhausted retries");
 703         ret = -EREMOTEIO;
 704  out:
 705         i2c_pxa_set_slave(i2c, ret);
 706         return ret;
 707 }
 708
 709 /*
 710  * i2c_pxa_master_complete - complete the message and wake up.
 711  */
 712 static void i2c_pxa_master_complete(struct pxa_i2c *i2c, int ret)
 713 {
 714         i2c->msg_ptr = 0;
 715         i2c->msg = NULL;
 716         i2c->msg_idx ++;
 717         i2c->msg_num = 0;
 718         if (ret)
 719                 i2c->msg_idx = ret;
 720         if (!i2c->use_pio)
 721                 wake_up(&i2c->wait);
 722 }
 723
 724 static void i2c_pxa_irq_txempty(struct pxa_i2c *i2c, u32 isr)
 725 {
 726         u32 icr = readl(_ICR(i2c)) & ~(ICR_START|ICR_STOP|ICR_ACKNAK|ICR_TB);
 727
 728  again:
 729         /*
 730          * If ISR_ALD is set, we lost arbitration.
 731          */
 732         if (isr & ISR_ALD) {
 733                 /*
 734                  * Do we need to do anything here?  The PXA docs
 735                  * are vague about what happens.
 736                  */
 737                 i2c_pxa_scream_blue_murder(i2c, "ALD set");
 738
 739                 /*
 740                  * We ignore this error.  We seem to see spurious ALDs
 741                  * for seemingly no reason.  If we handle them as I think
 742                  * they should, we end up causing an I2C error, which
 743                  * is painful for some systems.
 744                  */
 745                 return; /* ignore */
 746         }
 747
 748         if (isr & ISR_BED) {
 749                 int ret = BUS_ERROR;
 750
 751                 /*
 752                  * I2C bus error - either the device NAK'd us, or
 753                  * something more serious happened.  If we were NAK'd
 754                  * on the initial address phase, we can retry.
 755                  */
 756                 if (isr & ISR_ACKNAK) {
 757                         if (i2c->msg_ptr == 0 && i2c->msg_idx == 0)
 758                                 ret = I2C_RETRY;
 759                         else
 760                                 ret = XFER_NAKED;
 761                 }
 762                 i2c_pxa_master_complete(i2c, ret);
 763         } else if (isr & ISR_RWM) {
 764                 /*
 765                  * Read mode.  We have just sent the address byte, and
 766                  * now we must initiate the transfer.
 767                  */
 768                 if (i2c->msg_ptr == i2c->msg->len - 1 &&
 769                     i2c->msg_idx == i2c->msg_num - 1)
 770                         icr |= ICR_STOP | ICR_ACKNAK;
 771
 772                 icr |= ICR_ALDIE | ICR_TB;
 773         } else if (i2c->msg_ptr < i2c->msg->len) {
 774                 /*
 775                  * Write mode.  Write the next data byte.
 776                  */
 777                 writel(i2c->msg->buf[i2c->msg_ptr++], _IDBR(i2c));
 778
 779                 icr |= ICR_ALDIE | ICR_TB;
 780
 781                 /*
 782                  * If this is the last byte of the last message, send
 783                  * a STOP.
 784                  */
 785                 if (i2c->msg_ptr == i2c->msg->len &&
 786                     i2c->msg_idx == i2c->msg_num - 1)
 787                         icr |= ICR_STOP;
 788         } else if (i2c->msg_idx < i2c->msg_num - 1) {
 789                 /*
 790                  * Next segment of the message.
 791                  */
 792                 i2c->msg_ptr = 0;
 793                 i2c->msg_idx ++;
 794                 i2c->msg++;
 795
 796                 /*
 797                  * If we aren't doing a repeated start and address,
 798                  * go back and try to send the next byte.  Note that
 799                  * we do not support switching the R/W direction here.
 800                  */
 801                 if (i2c->msg->flags & I2C_M_NOSTART)
 802                         goto again;
 803
 804                 /*
 805                  * Write the next address.
 806                  */
 807                 writel(i2c_pxa_addr_byte(i2c->msg), _IDBR(i2c));
 808
 809                 /*
 810                  * And trigger a repeated start, and send the byte.
 811                  */
 812                 icr &= ~ICR_ALDIE;
 813                 icr |= ICR_START | ICR_TB;
 814         } else {
 815                 if (i2c->msg->len == 0) {
 816                         /*
 817                          * Device probes have a message length of zero
 818                          * and need the bus to be reset before it can
 819                          * be used again.
 820                          */
 821                         i2c_pxa_reset(i2c);
 822                 }
 823                 i2c_pxa_master_complete(i2c, 0);
 824         }
 825
 826         i2c->icrlog[i2c->irqlogidx-1] = icr;
 827
 828         writel(icr, _ICR(i2c));
 829         show_state(i2c);
 830 }
 831
 832 static void i2c_pxa_irq_rxfull(struct pxa_i2c *i2c, u32 isr)
 833 {
 834         u32 icr = readl(_ICR(i2c)) & ~(ICR_START|ICR_STOP|ICR_ACKNAK|ICR_TB);
 835
 836         /*
 837          * Read the byte.
 838          */
 839         i2c->msg->buf[i2c->msg_ptr++] = readl(_IDBR(i2c));
 840
 841         if (i2c->msg_ptr < i2c->msg->len) {
 842                 /*
 843                  * If this is the last byte of the last
 844                  * message, send a STOP.
 845                  */
 846                 if (i2c->msg_ptr == i2c->msg->len - 1)
 847                         icr |= ICR_STOP | ICR_ACKNAK;
 848
 849                 icr |= ICR_ALDIE | ICR_TB;
 850         } else {
 851                 i2c_pxa_master_complete(i2c, 0);
 852         }
 853
 854         i2c->icrlog[i2c->irqlogidx-1] = icr;
 855
 856         writel(icr, _ICR(i2c));
 857 }
 858
 859 static irqreturn_t i2c_pxa_handler(int this_irq, void *dev_id)
 860 {
 861         struct pxa_i2c *i2c = dev_id;
 862         u32 isr = readl(_ISR(i2c));
 863
 864         if (i2c_debug > 2 && 0) {
 865                 dev_dbg(&i2c->adap.dev, "%s: ISR=%08x, ICR=%08x, IBMR=%02x\n",
 866                         __func__, isr, readl(_ICR(i2c)), readl(_IBMR(i2c)));
 867                 decode_ISR(isr);
 868         }
 869
 870         if (i2c->irqlogidx < ARRAY_SIZE(i2c->isrlog))
 871                 i2c->isrlog[i2c->irqlogidx++] = isr;
 872
 873         show_state(i2c);
 874
 875         /*
 876          * Always clear all pending IRQs.
 877          */
 878         writel(isr & (ISR_SSD|ISR_ALD|ISR_ITE|ISR_IRF|ISR_SAD|ISR_BED), _ISR(i2c));
 879
 880         if (isr & ISR_SAD)
 881                 i2c_pxa_slave_start(i2c, isr);
 882         if (isr & ISR_SSD)
 883                 i2c_pxa_slave_stop(i2c);
 884
 885         if (i2c_pxa_is_slavemode(i2c)) {
 886                 if (isr & ISR_ITE)
 887                         i2c_pxa_slave_txempty(i2c, isr);
 888                 if (isr & ISR_IRF)
 889                         i2c_pxa_slave_rxfull(i2c, isr);
 890         } else if (i2c->msg) {
 891                 if (isr & ISR_ITE)
 892                         i2c_pxa_irq_txempty(i2c, isr);
 893                 if (isr & ISR_IRF)
 894                         i2c_pxa_irq_rxfull(i2c, isr);
 895         } else {
 896                 i2c_pxa_scream_blue_murder(i2c, "spurious irq");
 897         }
 898
 899         return IRQ_HANDLED;
 900 }
 901
 902
 903 static int i2c_pxa_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
 904 {
 905         struct pxa_i2c *i2c = adap->algo_data;
 906         int ret, i;
 907
 908         /* If the I2C controller is disabled we need to reset it (probably due
 909            to a suspend/resume destroying state). We do this here as we can then
 910            avoid worrying about resuming the controller before its users. */
 911         if (!(readl(_ICR(i2c)) & ICR_IUE))
 912                 i2c_pxa_reset(i2c);
 913
 914         for (i = adap->retries; i >= 0; i--) {
 915                 ret = i2c_pxa_do_xfer(i2c, msgs, num);
 916                 if (ret != I2C_RETRY)
 917                         goto out;
 918
 919                 if (i2c_debug)
 920                         dev_dbg(&adap->dev, "Retrying transmission\n");
 921                 udelay(100);
 922         }
 923         i2c_pxa_scream_blue_murder(i2c, "exhausted retries");
 924         ret = -EREMOTEIO;
 925  out:
 926         i2c_pxa_set_slave(i2c, ret);
 927         return ret;
 928 }
 929
 930 static u32 i2c_pxa_functionality(struct i2c_adapter *adap)
 931 {
 932         return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
 933 }
 934
 935 static const struct i2c_algorithm i2c_pxa_algorithm = {
 936         .master_xfer    = i2c_pxa_xfer,
 937         .functionality  = i2c_pxa_functionality,
 938 };
 939
 940 static const struct i2c_algorithm i2c_pxa_pio_algorithm = {
 941         .master_xfer    = i2c_pxa_pio_xfer,
 942         .functionality  = i2c_pxa_functionality,
 943 };
 944
 945 static void i2c_pxa_enable(struct platform_device *dev)
 946 {
 947         if (cpu_is_pxa27x()) {
 948                 switch (dev->id) {
 949                 case 0:
 950                         pxa_gpio_mode(GPIO117_I2CSCL_MD);
 951                         pxa_gpio_mode(GPIO118_I2CSDA_MD);
 952                         break;
 953                 case 1:
 954                         local_irq_disable();
 955                         PCFR |= PCFR_PI2CEN;
 956                         local_irq_enable();
 957                         break;
 958                 }
 959         }
 960 }
 961
 962 static void i2c_pxa_disable(struct platform_device *dev)
 963 {
 964         if (cpu_is_pxa27x() && dev->id == 1) {
 965                 local_irq_disable();
 966                 PCFR &= ~PCFR_PI2CEN;
 967                 local_irq_enable();
 968         }
 969 }
 970
 971 #define res_len(r)              ((r)->end - (r)->start + 1)
 972 static int i2c_pxa_probe(struct platform_device *dev)
 973 {
 974         struct pxa_i2c *i2c;
 975         struct resource *res;
 976         struct i2c_pxa_platform_data *plat = dev->dev.platform_data;
 977         int ret;
 978         int irq;
 979
 980         res = platform_get_resource(dev, IORESOURCE_MEM, 0);
 981         irq = platform_get_irq(dev, 0);
 982         if (res == NULL || irq < 0)
 983                 return -ENODEV;
 984
 985         if (!request_mem_region(res->start, res_len(res), res->name))
 986                 return -ENOMEM;
 987
 988         i2c = kzalloc(sizeof(struct pxa_i2c), GFP_KERNEL);
 989         if (!i2c) {
 990                 ret = -ENOMEM;
 991                 goto emalloc;
 992         }
 993
 994         i2c->adap.owner   = THIS_MODULE;
 995         i2c->adap.retries = 5;
 996
 997         spin_lock_init(&i2c->lock);
 998         init_waitqueue_head(&i2c->wait);
 999
1000         sprintf(i2c->adap.name, "pxa_i2c-i2c.%u", dev->id);
1001
1002         i2c->clk = clk_get(&dev->dev, "I2CCLK");
1003         if (IS_ERR(i2c->clk)) {
1004                 ret = PTR_ERR(i2c->clk);
1005                 goto eclk;
1006         }
1007
1008         i2c->reg_base = ioremap(res->start, res_len(res));
1009         if (!i2c->reg_base) {
1010                 ret = -EIO;
1011                 goto eremap;
1012         }
1013
1014         i2c->iobase = res->start;
1015         i2c->iosize = res_len(res);
1016
1017         i2c->irq = irq;
1018
1019         i2c->slave_addr = I2C_PXA_SLAVE_ADDR;
1020
1021 #ifdef CONFIG_I2C_PXA_SLAVE
1022         if (plat) {
1023                 i2c->slave_addr = plat->slave_addr;
1024                 i2c->slave = plat->slave;
1025         }
1026 #endif
1027
1028         clk_enable(i2c->clk);
1029         i2c_pxa_enable(dev);
1030
1031         if (plat) {
1032                 i2c->adap.class = plat->class;
1033                 i2c->use_pio = plat->use_pio;
1034         }
1035
1036         if (i2c->use_pio) {
1037                 i2c->adap.algo = &i2c_pxa_pio_algorithm;
1038         } else {
1039                 i2c->adap.algo = &i2c_pxa_algorithm;
1040                 ret = request_irq(irq, i2c_pxa_handler, IRQF_DISABLED,
1041                                   i2c->adap.name, i2c);
1042                 if (ret)
1043                         goto ereqirq;
1044         }
1045
1046         i2c_pxa_reset(i2c);
1047
1048         i2c->adap.algo_data = i2c;
1049         i2c->adap.dev.parent = &dev->dev;
1050
1051         /*
1052          * If "dev->id" is negative we consider it as zero.
1053          * The reason to do so is to avoid sysfs names that only make
1054          * sense when there are multiple adapters.
1055          */
1056         i2c->adap.nr = dev->id != -1 ? dev->id : 0;
1057
1058         ret = i2c_add_numbered_adapter(&i2c->adap);
1059         if (ret < 0) {
1060                 printk(KERN_INFO "I2C: Failed to add bus\n");
1061                 goto eadapt;
1062         }
1063
1064         platform_set_drvdata(dev, i2c);
1065
1066 #ifdef CONFIG_I2C_PXA_SLAVE
1067         printk(KERN_INFO "I2C: %s: PXA I2C adapter, slave address %d\n",
1068                i2c->adap.dev.bus_id, i2c->slave_addr);
1069 #else
1070         printk(KERN_INFO "I2C: %s: PXA I2C adapter\n",
1071                i2c->adap.dev.bus_id);
1072 #endif
1073         return 0;
1074
1075 eadapt:
1076         if (!i2c->use_pio)
1077                 free_irq(irq, i2c);
1078 ereqirq:
1079         clk_disable(i2c->clk);
1080         i2c_pxa_disable(dev);
1081 eremap:
1082         clk_put(i2c->clk);
1083 eclk:
1084         kfree(i2c);
1085 emalloc:
1086         release_mem_region(res->start, res_len(res));
1087         return ret;
1088 }
1089
1090 static int i2c_pxa_remove(struct platform_device *dev)
1091 {
1092         struct pxa_i2c *i2c = platform_get_drvdata(dev);
1093
1094         platform_set_drvdata(dev, NULL);
1095
1096         i2c_del_adapter(&i2c->adap);
1097         if (!i2c->use_pio)
1098                 free_irq(i2c->irq, i2c);
1099
1100         clk_disable(i2c->clk);
1101         clk_put(i2c->clk);
1102         i2c_pxa_disable(dev);
1103
1104         release_mem_region(i2c->iobase, i2c->iosize);
1105         kfree(i2c);
1106
1107         return 0;
1108 }
1109
1110 static struct platform_driver i2c_pxa_driver = {
1111         .probe          = i2c_pxa_probe,
1112         .remove         = i2c_pxa_remove,
1113         .driver         = {
1114                 .name   = "pxa2xx-i2c",
1115         },
1116 };
1117
1118 static int __init i2c_adap_pxa_init(void)
1119 {
1120         return platform_driver_register(&i2c_pxa_driver);
1121 }
1122
1123 static void i2c_adap_pxa_exit(void)
1124 {
1125         return platform_driver_unregister(&i2c_pxa_driver);
1126 }
1127
1128 MODULE_LICENSE("GPL");
1129
1130 module_init(i2c_adap_pxa_init);
1131 module_exit(i2c_adap_pxa_exit);