git.oblomov.eu Git - linux-2.6/blob - drivers/i2c/busses/i2c-pxa.c

   1 /*
   2  *  i2c_adap_pxa.c
   3  *
   4  *  I2C adapter for the PXA I2C bus access.
   5  *
   6  *  Copyright (C) 2002 Intrinsyc Software Inc.
   7  *  Copyright (C) 2004-2005 Deep Blue Solutions Ltd.
   8  *
   9  *  This program is free software; you can redistribute it and/or modify
  10  *  it under the terms of the GNU General Public License version 2 as
  11  *  published by the Free Software Foundation.
  12  *
  13  *  History:
  14  *    Apr 2002: Initial version [CS]
  15  *    Jun 2002: Properly seperated algo/adap [FB]
  16  *    Jan 2003: Fixed several bugs concerning interrupt handling [Kai-Uwe Bloem]
  17  *    Jan 2003: added limited signal handling [Kai-Uwe Bloem]
  18  *    Sep 2004: Major rework to ensure efficient bus handling [RMK]
  19  *    Dec 2004: Added support for PXA27x and slave device probing [Liam Girdwood]
  20  *    Feb 2005: Rework slave mode handling [RMK]
  21  */
  22 #include <linux/kernel.h>
  23 #include <linux/module.h>
  24 #include <linux/i2c.h>
  25 #include <linux/i2c-id.h>
  26 #include <linux/init.h>
  27 #include <linux/time.h>
  28 #include <linux/sched.h>
  29 #include <linux/delay.h>
  30 #include <linux/errno.h>
  31 #include <linux/interrupt.h>
  32 #include <linux/i2c-pxa.h>
  33 #include <linux/platform_device.h>
  34 #include <linux/err.h>
  35 #include <linux/clk.h>
  36
  37 #include <mach/hardware.h>
  38 #include <asm/irq.h>
  39 #include <asm/io.h>
  40 #include <mach/i2c.h>
  41
  42 /*
  43  * I2C registers and bit definitions
  44  */
  45 #define IBMR            (0x00)
  46 #define IDBR            (0x08)
  47 #define ICR             (0x10)
  48 #define ISR             (0x18)
  49 #define ISAR            (0x20)
  50
  51 #define ICR_START       (1 << 0)           /* start bit */
  52 #define ICR_STOP        (1 << 1)           /* stop bit */
  53 #define ICR_ACKNAK      (1 << 2)           /* send ACK(0) or NAK(1) */
  54 #define ICR_TB          (1 << 3)           /* transfer byte bit */
  55 #define ICR_MA          (1 << 4)           /* master abort */
  56 #define ICR_SCLE        (1 << 5)           /* master clock enable */
  57 #define ICR_IUE         (1 << 6)           /* unit enable */
  58 #define ICR_GCD         (1 << 7)           /* general call disable */
  59 #define ICR_ITEIE       (1 << 8)           /* enable tx interrupts */
  60 #define ICR_IRFIE       (1 << 9)           /* enable rx interrupts */
  61 #define ICR_BEIE        (1 << 10)          /* enable bus error ints */
  62 #define ICR_SSDIE       (1 << 11)          /* slave STOP detected int enable */
  63 #define ICR_ALDIE       (1 << 12)          /* enable arbitration interrupt */
  64 #define ICR_SADIE       (1 << 13)          /* slave address detected int enable */
  65 #define ICR_UR          (1 << 14)          /* unit reset */
  66 #define ICR_FM          (1 << 15)          /* fast mode */
  67
  68 #define ISR_RWM         (1 << 0)           /* read/write mode */
  69 #define ISR_ACKNAK      (1 << 1)           /* ack/nak status */
  70 #define ISR_UB          (1 << 2)           /* unit busy */
  71 #define ISR_IBB         (1 << 3)           /* bus busy */
  72 #define ISR_SSD         (1 << 4)           /* slave stop detected */
  73 #define ISR_ALD         (1 << 5)           /* arbitration loss detected */
  74 #define ISR_ITE         (1 << 6)           /* tx buffer empty */
  75 #define ISR_IRF         (1 << 7)           /* rx buffer full */
  76 #define ISR_GCAD        (1 << 8)           /* general call address detected */
  77 #define ISR_SAD         (1 << 9)           /* slave address detected */
  78 #define ISR_BED         (1 << 10)          /* bus error no ACK/NAK */
  79
  80 struct pxa_i2c {
  81         spinlock_t              lock;
  82         wait_queue_head_t       wait;
  83         struct i2c_msg          *msg;
  84         unsigned int            msg_num;
  85         unsigned int            msg_idx;
  86         unsigned int            msg_ptr;
  87         unsigned int            slave_addr;
  88
  89         struct i2c_adapter      adap;
  90         struct clk              *clk;
  91 #ifdef CONFIG_I2C_PXA_SLAVE
  92         struct i2c_slave_client *slave;
  93 #endif
  94
  95         unsigned int            irqlogidx;
  96         u32                     isrlog[32];
  97         u32                     icrlog[32];
  98
  99         void __iomem            *reg_base;
 100         unsigned int            reg_shift;
 101
 102         unsigned long           iobase;
 103         unsigned long           iosize;
 104
 105         int                     irq;
 106         unsigned int            use_pio :1;
 107         unsigned int            fast_mode :1;
 108 };
 109
 110 #define _IBMR(i2c)      ((i2c)->reg_base + (0x0 << (i2c)->reg_shift))
 111 #define _IDBR(i2c)      ((i2c)->reg_base + (0x4 << (i2c)->reg_shift))
 112 #define _ICR(i2c)       ((i2c)->reg_base + (0x8 << (i2c)->reg_shift))
 113 #define _ISR(i2c)       ((i2c)->reg_base + (0xc << (i2c)->reg_shift))
 114 #define _ISAR(i2c)      ((i2c)->reg_base + (0x10 << (i2c)->reg_shift))
 115
 116 /*
 117  * I2C Slave mode address
 118  */
 119 #define I2C_PXA_SLAVE_ADDR      0x1
 120
 121 #ifdef DEBUG
 122
 123 struct bits {
 124         u32     mask;
 125         const char *set;
 126         const char *unset;
 127 };
 128 #define PXA_BIT(m, s, u)        { .mask = m, .set = s, .unset = u }
 129
 130 static inline void
 131 decode_bits(const char *prefix, const struct bits *bits, int num, u32 val)
 132 {
 133         printk("%s %08x: ", prefix, val);
 134         while (num--) {
 135                 const char *str = val & bits->mask ? bits->set : bits->unset;
 136                 if (str)
 137                         printk("%s ", str);
 138                 bits++;
 139         }
 140 }
 141
 142 static const struct bits isr_bits[] = {
 143         PXA_BIT(ISR_RWM,        "RX",           "TX"),
 144         PXA_BIT(ISR_ACKNAK,     "NAK",          "ACK"),
 145         PXA_BIT(ISR_UB,         "Bsy",          "Rdy"),
 146         PXA_BIT(ISR_IBB,        "BusBsy",       "BusRdy"),
 147         PXA_BIT(ISR_SSD,        "SlaveStop",    NULL),
 148         PXA_BIT(ISR_ALD,        "ALD",          NULL),
 149         PXA_BIT(ISR_ITE,        "TxEmpty",      NULL),
 150         PXA_BIT(ISR_IRF,        "RxFull",       NULL),
 151         PXA_BIT(ISR_GCAD,       "GenCall",      NULL),
 152         PXA_BIT(ISR_SAD,        "SlaveAddr",    NULL),
 153         PXA_BIT(ISR_BED,        "BusErr",       NULL),
 154 };
 155
 156 static void decode_ISR(unsigned int val)
 157 {
 158         decode_bits(KERN_DEBUG "ISR", isr_bits, ARRAY_SIZE(isr_bits), val);
 159         printk("\n");
 160 }
 161
 162 static const struct bits icr_bits[] = {
 163         PXA_BIT(ICR_START,  "START",    NULL),
 164         PXA_BIT(ICR_STOP,   "STOP",     NULL),
 165         PXA_BIT(ICR_ACKNAK, "ACKNAK",   NULL),
 166         PXA_BIT(ICR_TB,     "TB",       NULL),
 167         PXA_BIT(ICR_MA,     "MA",       NULL),
 168         PXA_BIT(ICR_SCLE,   "SCLE",     "scle"),
 169         PXA_BIT(ICR_IUE,    "IUE",      "iue"),
 170         PXA_BIT(ICR_GCD,    "GCD",      NULL),
 171         PXA_BIT(ICR_ITEIE,  "ITEIE",    NULL),
 172         PXA_BIT(ICR_IRFIE,  "IRFIE",    NULL),
 173         PXA_BIT(ICR_BEIE,   "BEIE",     NULL),
 174         PXA_BIT(ICR_SSDIE,  "SSDIE",    NULL),
 175         PXA_BIT(ICR_ALDIE,  "ALDIE",    NULL),
 176         PXA_BIT(ICR_SADIE,  "SADIE",    NULL),
 177         PXA_BIT(ICR_UR,     "UR",               "ur"),
 178 };
 179
 180 #ifdef CONFIG_I2C_PXA_SLAVE
 181 static void decode_ICR(unsigned int val)
 182 {
 183         decode_bits(KERN_DEBUG "ICR", icr_bits, ARRAY_SIZE(icr_bits), val);
 184         printk("\n");
 185 }
 186 #endif
 187
 188 static unsigned int i2c_debug = DEBUG;
 189
 190 static void i2c_pxa_show_state(struct pxa_i2c *i2c, int lno, const char *fname)
 191 {
 192         dev_dbg(&i2c->adap.dev, "state:%s:%d: ISR=%08x, ICR=%08x, IBMR=%02x\n", fname, lno,
 193                 readl(_ISR(i2c)), readl(_ICR(i2c)), readl(_IBMR(i2c)));
 194 }
 195
 196 #define show_state(i2c) i2c_pxa_show_state(i2c, __LINE__, __func__)
 197 #else
 198 #define i2c_debug       0
 199
 200 #define show_state(i2c) do { } while (0)
 201 #define decode_ISR(val) do { } while (0)
 202 #define decode_ICR(val) do { } while (0)
 203 #endif
 204
 205 #define eedbg(lvl, x...) do { if ((lvl) < 1) { printk(KERN_DEBUG "" x); } } while(0)
 206
 207 static void i2c_pxa_master_complete(struct pxa_i2c *i2c, int ret);
 208 static irqreturn_t i2c_pxa_handler(int this_irq, void *dev_id);
 209
 210 static void i2c_pxa_scream_blue_murder(struct pxa_i2c *i2c, const char *why)
 211 {
 212         unsigned int i;
 213         printk("i2c: error: %s\n", why);
 214         printk("i2c: msg_num: %d msg_idx: %d msg_ptr: %d\n",
 215                 i2c->msg_num, i2c->msg_idx, i2c->msg_ptr);
 216         printk("i2c: ICR: %08x ISR: %08x\n"
 217                "i2c: log: ", readl(_ICR(i2c)), readl(_ISR(i2c)));
 218         for (i = 0; i < i2c->irqlogidx; i++)
 219                 printk("[%08x:%08x] ", i2c->isrlog[i], i2c->icrlog[i]);
 220         printk("\n");
 221 }
 222
 223 static inline int i2c_pxa_is_slavemode(struct pxa_i2c *i2c)
 224 {
 225         return !(readl(_ICR(i2c)) & ICR_SCLE);
 226 }
 227
 228 static void i2c_pxa_abort(struct pxa_i2c *i2c)
 229 {
 230         int i = 250;
 231
 232         if (i2c_pxa_is_slavemode(i2c)) {
 233                 dev_dbg(&i2c->adap.dev, "%s: called in slave mode\n", __func__);
 234                 return;
 235         }
 236
 237         while ((i > 0) && (readl(_IBMR(i2c)) & 0x1) == 0) {
 238                 unsigned long icr = readl(_ICR(i2c));
 239
 240                 icr &= ~ICR_START;
 241                 icr |= ICR_ACKNAK | ICR_STOP | ICR_TB;
 242
 243                 writel(icr, _ICR(i2c));
 244
 245                 show_state(i2c);
 246
 247                 mdelay(1);
 248                 i --;
 249         }
 250
 251         writel(readl(_ICR(i2c)) & ~(ICR_MA | ICR_START | ICR_STOP),
 252                _ICR(i2c));
 253 }
 254
 255 static int i2c_pxa_wait_bus_not_busy(struct pxa_i2c *i2c)
 256 {
 257         int timeout = DEF_TIMEOUT;
 258
 259         while (timeout-- && readl(_ISR(i2c)) & (ISR_IBB | ISR_UB)) {
 260                 if ((readl(_ISR(i2c)) & ISR_SAD) != 0)
 261                         timeout += 4;
 262
 263                 msleep(2);
 264                 show_state(i2c);
 265         }
 266
 267         if (timeout <= 0)
 268                 show_state(i2c);
 269
 270         return timeout <= 0 ? I2C_RETRY : 0;
 271 }
 272
 273 static int i2c_pxa_wait_master(struct pxa_i2c *i2c)
 274 {
 275         unsigned long timeout = jiffies + HZ*4;
 276
 277         while (time_before(jiffies, timeout)) {
 278                 if (i2c_debug > 1)
 279                         dev_dbg(&i2c->adap.dev, "%s: %ld: ISR=%08x, ICR=%08x, IBMR=%02x\n",
 280                                 __func__, (long)jiffies, readl(_ISR(i2c)), readl(_ICR(i2c)), readl(_IBMR(i2c)));
 281
 282                 if (readl(_ISR(i2c)) & ISR_SAD) {
 283                         if (i2c_debug > 0)
 284                                 dev_dbg(&i2c->adap.dev, "%s: Slave detected\n", __func__);
 285                         goto out;
 286                 }
 287
 288                 /* wait for unit and bus being not busy, and we also do a
 289                  * quick check of the i2c lines themselves to ensure they've
 290                  * gone high...
 291                  */
 292                 if ((readl(_ISR(i2c)) & (ISR_UB | ISR_IBB)) == 0 && readl(_IBMR(i2c)) == 3) {
 293                         if (i2c_debug > 0)
 294                                 dev_dbg(&i2c->adap.dev, "%s: done\n", __func__);
 295                         return 1;
 296                 }
 297
 298                 msleep(1);
 299         }
 300
 301         if (i2c_debug > 0)
 302                 dev_dbg(&i2c->adap.dev, "%s: did not free\n", __func__);
 303  out:
 304         return 0;
 305 }
 306
 307 static int i2c_pxa_set_master(struct pxa_i2c *i2c)
 308 {
 309         if (i2c_debug)
 310                 dev_dbg(&i2c->adap.dev, "setting to bus master\n");
 311
 312         if ((readl(_ISR(i2c)) & (ISR_UB | ISR_IBB)) != 0) {
 313                 dev_dbg(&i2c->adap.dev, "%s: unit is busy\n", __func__);
 314                 if (!i2c_pxa_wait_master(i2c)) {
 315                         dev_dbg(&i2c->adap.dev, "%s: error: unit busy\n", __func__);
 316                         return I2C_RETRY;
 317                 }
 318         }
 319
 320         writel(readl(_ICR(i2c)) | ICR_SCLE, _ICR(i2c));
 321         return 0;
 322 }
 323
 324 #ifdef CONFIG_I2C_PXA_SLAVE
 325 static int i2c_pxa_wait_slave(struct pxa_i2c *i2c)
 326 {
 327         unsigned long timeout = jiffies + HZ*1;
 328
 329         /* wait for stop */
 330
 331         show_state(i2c);
 332
 333         while (time_before(jiffies, timeout)) {
 334                 if (i2c_debug > 1)
 335                         dev_dbg(&i2c->adap.dev, "%s: %ld: ISR=%08x, ICR=%08x, IBMR=%02x\n",
 336                                 __func__, (long)jiffies, readl(_ISR(i2c)), readl(_ICR(i2c)), readl(_IBMR(i2c)));
 337
 338                 if ((readl(_ISR(i2c)) & (ISR_UB|ISR_IBB)) == 0 ||
 339                     (readl(_ISR(i2c)) & ISR_SAD) != 0 ||
 340                     (readl(_ICR(i2c)) & ICR_SCLE) == 0) {
 341                         if (i2c_debug > 1)
 342                                 dev_dbg(&i2c->adap.dev, "%s: done\n", __func__);
 343                         return 1;
 344                 }
 345
 346                 msleep(1);
 347         }
 348
 349         if (i2c_debug > 0)
 350                 dev_dbg(&i2c->adap.dev, "%s: did not free\n", __func__);
 351         return 0;
 352 }
 353
 354 /*
 355  * clear the hold on the bus, and take of anything else
 356  * that has been configured
 357  */
 358 static void i2c_pxa_set_slave(struct pxa_i2c *i2c, int errcode)
 359 {
 360         show_state(i2c);
 361
 362         if (errcode < 0) {
 363                 udelay(100);   /* simple delay */
 364         } else {
 365                 /* we need to wait for the stop condition to end */
 366
 367                 /* if we where in stop, then clear... */
 368                 if (readl(_ICR(i2c)) & ICR_STOP) {
 369                         udelay(100);
 370                         writel(readl(_ICR(i2c)) & ~ICR_STOP, _ICR(i2c));
 371                 }
 372
 373                 if (!i2c_pxa_wait_slave(i2c)) {
 374                         dev_err(&i2c->adap.dev, "%s: wait timedout\n",
 375                                 __func__);
 376                         return;
 377                 }
 378         }
 379
 380         writel(readl(_ICR(i2c)) & ~(ICR_STOP|ICR_ACKNAK|ICR_MA), _ICR(i2c));
 381         writel(readl(_ICR(i2c)) & ~ICR_SCLE, _ICR(i2c));
 382
 383         if (i2c_debug) {
 384                 dev_dbg(&i2c->adap.dev, "ICR now %08x, ISR %08x\n", readl(_ICR(i2c)), readl(_ISR(i2c)));
 385                 decode_ICR(readl(_ICR(i2c)));
 386         }
 387 }
 388 #else
 389 #define i2c_pxa_set_slave(i2c, err)     do { } while (0)
 390 #endif
 391
 392 static void i2c_pxa_reset(struct pxa_i2c *i2c)
 393 {
 394         pr_debug("Resetting I2C Controller Unit\n");
 395
 396         /* abort any transfer currently under way */
 397         i2c_pxa_abort(i2c);
 398
 399         /* reset according to 9.8 */
 400         writel(ICR_UR, _ICR(i2c));
 401         writel(I2C_ISR_INIT, _ISR(i2c));
 402         writel(readl(_ICR(i2c)) & ~ICR_UR, _ICR(i2c));
 403
 404         writel(i2c->slave_addr, _ISAR(i2c));
 405
 406         /* set control register values */
 407         writel(I2C_ICR_INIT | (i2c->fast_mode ? ICR_FM : 0), _ICR(i2c));
 408
 409 #ifdef CONFIG_I2C_PXA_SLAVE
 410         dev_info(&i2c->adap.dev, "Enabling slave mode\n");
 411         writel(readl(_ICR(i2c)) | ICR_SADIE | ICR_ALDIE | ICR_SSDIE, _ICR(i2c));
 412 #endif
 413
 414         i2c_pxa_set_slave(i2c, 0);
 415
 416         /* enable unit */
 417         writel(readl(_ICR(i2c)) | ICR_IUE, _ICR(i2c));
 418         udelay(100);
 419 }
 420
 421
 422 #ifdef CONFIG_I2C_PXA_SLAVE
 423 /*
 424  * PXA I2C Slave mode
 425  */
 426
 427 static void i2c_pxa_slave_txempty(struct pxa_i2c *i2c, u32 isr)
 428 {
 429         if (isr & ISR_BED) {
 430                 /* what should we do here? */
 431         } else {
 432                 int ret = 0;
 433
 434                 if (i2c->slave != NULL)
 435                         ret = i2c->slave->read(i2c->slave->data);
 436
 437                 writel(ret, _IDBR(i2c));
 438                 writel(readl(_ICR(i2c)) | ICR_TB, _ICR(i2c));   /* allow next byte */
 439         }
 440 }
 441
 442 static void i2c_pxa_slave_rxfull(struct pxa_i2c *i2c, u32 isr)
 443 {
 444         unsigned int byte = readl(_IDBR(i2c));
 445
 446         if (i2c->slave != NULL)
 447                 i2c->slave->write(i2c->slave->data, byte);
 448
 449         writel(readl(_ICR(i2c)) | ICR_TB, _ICR(i2c));
 450 }
 451
 452 static void i2c_pxa_slave_start(struct pxa_i2c *i2c, u32 isr)
 453 {
 454         int timeout;
 455
 456         if (i2c_debug > 0)
 457                 dev_dbg(&i2c->adap.dev, "SAD, mode is slave-%cx\n",
 458                        (isr & ISR_RWM) ? 'r' : 't');
 459
 460         if (i2c->slave != NULL)
 461                 i2c->slave->event(i2c->slave->data,
 462                                  (isr & ISR_RWM) ? I2C_SLAVE_EVENT_START_READ : I2C_SLAVE_EVENT_START_WRITE);
 463
 464         /*
 465          * slave could interrupt in the middle of us generating a
 466          * start condition... if this happens, we'd better back off
 467          * and stop holding the poor thing up
 468          */
 469         writel(readl(_ICR(i2c)) & ~(ICR_START|ICR_STOP), _ICR(i2c));
 470         writel(readl(_ICR(i2c)) | ICR_TB, _ICR(i2c));
 471
 472         timeout = 0x10000;
 473
 474         while (1) {
 475                 if ((readl(_IBMR(i2c)) & 2) == 2)
 476                         break;
 477
 478                 timeout--;
 479
 480                 if (timeout <= 0) {
 481                         dev_err(&i2c->adap.dev, "timeout waiting for SCL high\n");
 482                         break;
 483                 }
 484         }
 485
 486         writel(readl(_ICR(i2c)) & ~ICR_SCLE, _ICR(i2c));
 487 }
 488
 489 static void i2c_pxa_slave_stop(struct pxa_i2c *i2c)
 490 {
 491         if (i2c_debug > 2)
 492                 dev_dbg(&i2c->adap.dev, "ISR: SSD (Slave Stop)\n");
 493
 494         if (i2c->slave != NULL)
 495                 i2c->slave->event(i2c->slave->data, I2C_SLAVE_EVENT_STOP);
 496
 497         if (i2c_debug > 2)
 498                 dev_dbg(&i2c->adap.dev, "ISR: SSD (Slave Stop) acked\n");
 499
 500         /*
 501          * If we have a master-mode message waiting,
 502          * kick it off now that the slave has completed.
 503          */
 504         if (i2c->msg)
 505                 i2c_pxa_master_complete(i2c, I2C_RETRY);
 506 }
 507 #else
 508 static void i2c_pxa_slave_txempty(struct pxa_i2c *i2c, u32 isr)
 509 {
 510         if (isr & ISR_BED) {
 511                 /* what should we do here? */
 512         } else {
 513                 writel(0, _IDBR(i2c));
 514                 writel(readl(_ICR(i2c)) | ICR_TB, _ICR(i2c));
 515         }
 516 }
 517
 518 static void i2c_pxa_slave_rxfull(struct pxa_i2c *i2c, u32 isr)
 519 {
 520         writel(readl(_ICR(i2c)) | ICR_TB | ICR_ACKNAK, _ICR(i2c));
 521 }
 522
 523 static void i2c_pxa_slave_start(struct pxa_i2c *i2c, u32 isr)
 524 {
 525         int timeout;
 526
 527         /*
 528          * slave could interrupt in the middle of us generating a
 529          * start condition... if this happens, we'd better back off
 530          * and stop holding the poor thing up
 531          */
 532         writel(readl(_ICR(i2c)) & ~(ICR_START|ICR_STOP), _ICR(i2c));
 533         writel(readl(_ICR(i2c)) | ICR_TB | ICR_ACKNAK, _ICR(i2c));
 534
 535         timeout = 0x10000;
 536
 537         while (1) {
 538                 if ((readl(_IBMR(i2c)) & 2) == 2)
 539                         break;
 540
 541                 timeout--;
 542
 543                 if (timeout <= 0) {
 544                         dev_err(&i2c->adap.dev, "timeout waiting for SCL high\n");
 545                         break;
 546                 }
 547         }
 548
 549         writel(readl(_ICR(i2c)) & ~ICR_SCLE, _ICR(i2c));
 550 }
 551
 552 static void i2c_pxa_slave_stop(struct pxa_i2c *i2c)
 553 {
 554         if (i2c->msg)
 555                 i2c_pxa_master_complete(i2c, I2C_RETRY);
 556 }
 557 #endif
 558
 559 /*
 560  * PXA I2C Master mode
 561  */
 562
 563 static inline unsigned int i2c_pxa_addr_byte(struct i2c_msg *msg)
 564 {
 565         unsigned int addr = (msg->addr & 0x7f) << 1;
 566
 567         if (msg->flags & I2C_M_RD)
 568                 addr |= 1;
 569
 570         return addr;
 571 }
 572
 573 static inline void i2c_pxa_start_message(struct pxa_i2c *i2c)
 574 {
 575         u32 icr;
 576
 577         /*
 578          * Step 1: target slave address into IDBR
 579          */
 580         writel(i2c_pxa_addr_byte(i2c->msg), _IDBR(i2c));
 581
 582         /*
 583          * Step 2: initiate the write.
 584          */
 585         icr = readl(_ICR(i2c)) & ~(ICR_STOP | ICR_ALDIE);
 586         writel(icr | ICR_START | ICR_TB, _ICR(i2c));
 587 }
 588
 589 static inline void i2c_pxa_stop_message(struct pxa_i2c *i2c)
 590 {
 591         u32 icr;
 592
 593         /*
 594          * Clear the STOP and ACK flags
 595          */
 596         icr = readl(_ICR(i2c));
 597         icr &= ~(ICR_STOP | ICR_ACKNAK);
 598         writel(icr, _ICR(i2c));
 599 }
 600
 601 static int i2c_pxa_pio_set_master(struct pxa_i2c *i2c)
 602 {
 603         /* make timeout the same as for interrupt based functions */
 604         long timeout = 2 * DEF_TIMEOUT;
 605
 606         /*
 607          * Wait for the bus to become free.
 608          */
 609         while (timeout-- && readl(_ISR(i2c)) & (ISR_IBB | ISR_UB)) {
 610                 udelay(1000);
 611                 show_state(i2c);
 612         }
 613
 614         if (timeout <= 0) {
 615                 show_state(i2c);
 616                 dev_err(&i2c->adap.dev,
 617                         "i2c_pxa: timeout waiting for bus free\n");
 618                 return I2C_RETRY;
 619         }
 620
 621         /*
 622          * Set master mode.
 623          */
 624         writel(readl(_ICR(i2c)) | ICR_SCLE, _ICR(i2c));
 625
 626         return 0;
 627 }
 628
 629 static int i2c_pxa_do_pio_xfer(struct pxa_i2c *i2c,
 630                                struct i2c_msg *msg, int num)
 631 {
 632         unsigned long timeout = 500000; /* 5 seconds */
 633         int ret = 0;
 634
 635         ret = i2c_pxa_pio_set_master(i2c);
 636         if (ret)
 637                 goto out;
 638
 639         i2c->msg = msg;
 640         i2c->msg_num = num;
 641         i2c->msg_idx = 0;
 642         i2c->msg_ptr = 0;
 643         i2c->irqlogidx = 0;
 644
 645         i2c_pxa_start_message(i2c);
 646
 647         while (i2c->msg_num > 0 && --timeout) {
 648                 i2c_pxa_handler(0, i2c);
 649                 udelay(10);
 650         }
 651
 652         i2c_pxa_stop_message(i2c);
 653
 654         /*
 655          * We place the return code in i2c->msg_idx.
 656          */
 657         ret = i2c->msg_idx;
 658
 659 out:
 660         if (timeout == 0)
 661                 i2c_pxa_scream_blue_murder(i2c, "timeout");
 662
 663         return ret;
 664 }
 665
 666 /*
 667  * We are protected by the adapter bus mutex.
 668  */
 669 static int i2c_pxa_do_xfer(struct pxa_i2c *i2c, struct i2c_msg *msg, int num)
 670 {
 671         long timeout;
 672         int ret;
 673
 674         /*
 675          * Wait for the bus to become free.
 676          */
 677         ret = i2c_pxa_wait_bus_not_busy(i2c);
 678         if (ret) {
 679                 dev_err(&i2c->adap.dev, "i2c_pxa: timeout waiting for bus free\n");
 680                 goto out;
 681         }
 682
 683         /*
 684          * Set master mode.
 685          */
 686         ret = i2c_pxa_set_master(i2c);
 687         if (ret) {
 688                 dev_err(&i2c->adap.dev, "i2c_pxa_set_master: error %d\n", ret);
 689                 goto out;
 690         }
 691
 692         spin_lock_irq(&i2c->lock);
 693
 694         i2c->msg = msg;
 695         i2c->msg_num = num;
 696         i2c->msg_idx = 0;
 697         i2c->msg_ptr = 0;
 698         i2c->irqlogidx = 0;
 699
 700         i2c_pxa_start_message(i2c);
 701
 702         spin_unlock_irq(&i2c->lock);
 703
 704         /*
 705          * The rest of the processing occurs in the interrupt handler.
 706          */
 707         timeout = wait_event_timeout(i2c->wait, i2c->msg_num == 0, HZ * 5);
 708         i2c_pxa_stop_message(i2c);
 709
 710         /*
 711          * We place the return code in i2c->msg_idx.
 712          */
 713         ret = i2c->msg_idx;
 714
 715         if (timeout == 0)
 716                 i2c_pxa_scream_blue_murder(i2c, "timeout");
 717
 718  out:
 719         return ret;
 720 }
 721
 722 static int i2c_pxa_pio_xfer(struct i2c_adapter *adap,
 723                             struct i2c_msg msgs[], int num)
 724 {
 725         struct pxa_i2c *i2c = adap->algo_data;
 726         int ret, i;
 727
 728         /* If the I2C controller is disabled we need to reset it
 729           (probably due to a suspend/resume destroying state). We do
 730           this here as we can then avoid worrying about resuming the
 731           controller before its users. */
 732         if (!(readl(_ICR(i2c)) & ICR_IUE))
 733                 i2c_pxa_reset(i2c);
 734
 735         for (i = adap->retries; i >= 0; i--) {
 736                 ret = i2c_pxa_do_pio_xfer(i2c, msgs, num);
 737                 if (ret != I2C_RETRY)
 738                         goto out;
 739
 740                 if (i2c_debug)
 741                         dev_dbg(&adap->dev, "Retrying transmission\n");
 742                 udelay(100);
 743         }
 744         i2c_pxa_scream_blue_murder(i2c, "exhausted retries");
 745         ret = -EREMOTEIO;
 746  out:
 747         i2c_pxa_set_slave(i2c, ret);
 748         return ret;
 749 }
 750
 751 /*
 752  * i2c_pxa_master_complete - complete the message and wake up.
 753  */
 754 static void i2c_pxa_master_complete(struct pxa_i2c *i2c, int ret)
 755 {
 756         i2c->msg_ptr = 0;
 757         i2c->msg = NULL;
 758         i2c->msg_idx ++;
 759         i2c->msg_num = 0;
 760         if (ret)
 761                 i2c->msg_idx = ret;
 762         if (!i2c->use_pio)
 763                 wake_up(&i2c->wait);
 764 }
 765
 766 static void i2c_pxa_irq_txempty(struct pxa_i2c *i2c, u32 isr)
 767 {
 768         u32 icr = readl(_ICR(i2c)) & ~(ICR_START|ICR_STOP|ICR_ACKNAK|ICR_TB);
 769
 770  again:
 771         /*
 772          * If ISR_ALD is set, we lost arbitration.
 773          */
 774         if (isr & ISR_ALD) {
 775                 /*
 776                  * Do we need to do anything here?  The PXA docs
 777                  * are vague about what happens.
 778                  */
 779                 i2c_pxa_scream_blue_murder(i2c, "ALD set");
 780
 781                 /*
 782                  * We ignore this error.  We seem to see spurious ALDs
 783                  * for seemingly no reason.  If we handle them as I think
 784                  * they should, we end up causing an I2C error, which
 785                  * is painful for some systems.
 786                  */
 787                 return; /* ignore */
 788         }
 789
 790         if (isr & ISR_BED) {
 791                 int ret = BUS_ERROR;
 792
 793                 /*
 794                  * I2C bus error - either the device NAK'd us, or
 795                  * something more serious happened.  If we were NAK'd
 796                  * on the initial address phase, we can retry.
 797                  */
 798                 if (isr & ISR_ACKNAK) {
 799                         if (i2c->msg_ptr == 0 && i2c->msg_idx == 0)
 800                                 ret = I2C_RETRY;
 801                         else
 802                                 ret = XFER_NAKED;
 803                 }
 804                 i2c_pxa_master_complete(i2c, ret);
 805         } else if (isr & ISR_RWM) {
 806                 /*
 807                  * Read mode.  We have just sent the address byte, and
 808                  * now we must initiate the transfer.
 809                  */
 810                 if (i2c->msg_ptr == i2c->msg->len - 1 &&
 811                     i2c->msg_idx == i2c->msg_num - 1)
 812                         icr |= ICR_STOP | ICR_ACKNAK;
 813
 814                 icr |= ICR_ALDIE | ICR_TB;
 815         } else if (i2c->msg_ptr < i2c->msg->len) {
 816                 /*
 817                  * Write mode.  Write the next data byte.
 818                  */
 819                 writel(i2c->msg->buf[i2c->msg_ptr++], _IDBR(i2c));
 820
 821                 icr |= ICR_ALDIE | ICR_TB;
 822
 823                 /*
 824                  * If this is the last byte of the last message, send
 825                  * a STOP.
 826                  */
 827                 if (i2c->msg_ptr == i2c->msg->len &&
 828                     i2c->msg_idx == i2c->msg_num - 1)
 829                         icr |= ICR_STOP;
 830         } else if (i2c->msg_idx < i2c->msg_num - 1) {
 831                 /*
 832                  * Next segment of the message.
 833                  */
 834                 i2c->msg_ptr = 0;
 835                 i2c->msg_idx ++;
 836                 i2c->msg++;
 837
 838                 /*
 839                  * If we aren't doing a repeated start and address,
 840                  * go back and try to send the next byte.  Note that
 841                  * we do not support switching the R/W direction here.
 842                  */
 843                 if (i2c->msg->flags & I2C_M_NOSTART)
 844                         goto again;
 845
 846                 /*
 847                  * Write the next address.
 848                  */
 849                 writel(i2c_pxa_addr_byte(i2c->msg), _IDBR(i2c));
 850
 851                 /*
 852                  * And trigger a repeated start, and send the byte.
 853                  */
 854                 icr &= ~ICR_ALDIE;
 855                 icr |= ICR_START | ICR_TB;
 856         } else {
 857                 if (i2c->msg->len == 0) {
 858                         /*
 859                          * Device probes have a message length of zero
 860                          * and need the bus to be reset before it can
 861                          * be used again.
 862                          */
 863                         i2c_pxa_reset(i2c);
 864                 }
 865                 i2c_pxa_master_complete(i2c, 0);
 866         }
 867
 868         i2c->icrlog[i2c->irqlogidx-1] = icr;
 869
 870         writel(icr, _ICR(i2c));
 871         show_state(i2c);
 872 }
 873
 874 static void i2c_pxa_irq_rxfull(struct pxa_i2c *i2c, u32 isr)
 875 {
 876         u32 icr = readl(_ICR(i2c)) & ~(ICR_START|ICR_STOP|ICR_ACKNAK|ICR_TB);
 877
 878         /*
 879          * Read the byte.
 880          */
 881         i2c->msg->buf[i2c->msg_ptr++] = readl(_IDBR(i2c));
 882
 883         if (i2c->msg_ptr < i2c->msg->len) {
 884                 /*
 885                  * If this is the last byte of the last
 886                  * message, send a STOP.
 887                  */
 888                 if (i2c->msg_ptr == i2c->msg->len - 1)
 889                         icr |= ICR_STOP | ICR_ACKNAK;
 890
 891                 icr |= ICR_ALDIE | ICR_TB;
 892         } else {
 893                 i2c_pxa_master_complete(i2c, 0);
 894         }
 895
 896         i2c->icrlog[i2c->irqlogidx-1] = icr;
 897
 898         writel(icr, _ICR(i2c));
 899 }
 900
 901 static irqreturn_t i2c_pxa_handler(int this_irq, void *dev_id)
 902 {
 903         struct pxa_i2c *i2c = dev_id;
 904         u32 isr = readl(_ISR(i2c));
 905
 906         if (i2c_debug > 2 && 0) {
 907                 dev_dbg(&i2c->adap.dev, "%s: ISR=%08x, ICR=%08x, IBMR=%02x\n",
 908                         __func__, isr, readl(_ICR(i2c)), readl(_IBMR(i2c)));
 909                 decode_ISR(isr);
 910         }
 911
 912         if (i2c->irqlogidx < ARRAY_SIZE(i2c->isrlog))
 913                 i2c->isrlog[i2c->irqlogidx++] = isr;
 914
 915         show_state(i2c);
 916
 917         /*
 918          * Always clear all pending IRQs.
 919          */
 920         writel(isr & (ISR_SSD|ISR_ALD|ISR_ITE|ISR_IRF|ISR_SAD|ISR_BED), _ISR(i2c));
 921
 922         if (isr & ISR_SAD)
 923                 i2c_pxa_slave_start(i2c, isr);
 924         if (isr & ISR_SSD)
 925                 i2c_pxa_slave_stop(i2c);
 926
 927         if (i2c_pxa_is_slavemode(i2c)) {
 928                 if (isr & ISR_ITE)
 929                         i2c_pxa_slave_txempty(i2c, isr);
 930                 if (isr & ISR_IRF)
 931                         i2c_pxa_slave_rxfull(i2c, isr);
 932         } else if (i2c->msg) {
 933                 if (isr & ISR_ITE)
 934                         i2c_pxa_irq_txempty(i2c, isr);
 935                 if (isr & ISR_IRF)
 936                         i2c_pxa_irq_rxfull(i2c, isr);
 937         } else {
 938                 i2c_pxa_scream_blue_murder(i2c, "spurious irq");
 939         }
 940
 941         return IRQ_HANDLED;
 942 }
 943
 944
 945 static int i2c_pxa_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
 946 {
 947         struct pxa_i2c *i2c = adap->algo_data;
 948         int ret, i;
 949
 950         for (i = adap->retries; i >= 0; i--) {
 951                 ret = i2c_pxa_do_xfer(i2c, msgs, num);
 952                 if (ret != I2C_RETRY)
 953                         goto out;
 954
 955                 if (i2c_debug)
 956                         dev_dbg(&adap->dev, "Retrying transmission\n");
 957                 udelay(100);
 958         }
 959         i2c_pxa_scream_blue_murder(i2c, "exhausted retries");
 960         ret = -EREMOTEIO;
 961  out:
 962         i2c_pxa_set_slave(i2c, ret);
 963         return ret;
 964 }
 965
 966 static u32 i2c_pxa_functionality(struct i2c_adapter *adap)
 967 {
 968         return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
 969 }
 970
 971 static const struct i2c_algorithm i2c_pxa_algorithm = {
 972         .master_xfer    = i2c_pxa_xfer,
 973         .functionality  = i2c_pxa_functionality,
 974 };
 975
 976 static const struct i2c_algorithm i2c_pxa_pio_algorithm = {
 977         .master_xfer    = i2c_pxa_pio_xfer,
 978         .functionality  = i2c_pxa_functionality,
 979 };
 980
 981 #define res_len(r)              ((r)->end - (r)->start + 1)
 982 static int i2c_pxa_probe(struct platform_device *dev)
 983 {
 984         struct pxa_i2c *i2c;
 985         struct resource *res;
 986         struct i2c_pxa_platform_data *plat = dev->dev.platform_data;
 987         int ret;
 988         int irq;
 989
 990         res = platform_get_resource(dev, IORESOURCE_MEM, 0);
 991         irq = platform_get_irq(dev, 0);
 992         if (res == NULL || irq < 0)
 993                 return -ENODEV;
 994
 995         if (!request_mem_region(res->start, res_len(res), res->name))
 996                 return -ENOMEM;
 997
 998         i2c = kzalloc(sizeof(struct pxa_i2c), GFP_KERNEL);
 999         if (!i2c) {
1000                 ret = -ENOMEM;
1001                 goto emalloc;
1002         }
1003
1004         i2c->adap.owner   = THIS_MODULE;
1005         i2c->adap.retries = 5;
1006
1007         spin_lock_init(&i2c->lock);
1008         init_waitqueue_head(&i2c->wait);
1009
1010         /*
1011          * If "dev->id" is negative we consider it as zero.
1012          * The reason to do so is to avoid sysfs names that only make
1013          * sense when there are multiple adapters.
1014          */
1015         i2c->adap.nr = dev->id != -1 ? dev->id : 0;
1016         snprintf(i2c->adap.name, sizeof(i2c->adap.name), "pxa_i2c-i2c.%u",
1017                  i2c->adap.nr);
1018
1019         i2c->clk = clk_get(&dev->dev, NULL);
1020         if (IS_ERR(i2c->clk)) {
1021                 ret = PTR_ERR(i2c->clk);
1022                 goto eclk;
1023         }
1024
1025         i2c->reg_base = ioremap(res->start, res_len(res));
1026         if (!i2c->reg_base) {
1027                 ret = -EIO;
1028                 goto eremap;
1029         }
1030         i2c->reg_shift = (cpu_is_pxa3xx() && (dev->id == 1)) ? 0 : 1;
1031
1032         i2c->iobase = res->start;
1033         i2c->iosize = res_len(res);
1034
1035         i2c->irq = irq;
1036
1037         i2c->slave_addr = I2C_PXA_SLAVE_ADDR;
1038
1039 #ifdef CONFIG_I2C_PXA_SLAVE
1040         if (plat) {
1041                 i2c->slave_addr = plat->slave_addr;
1042                 i2c->slave = plat->slave;
1043         }
1044 #endif
1045
1046         clk_enable(i2c->clk);
1047
1048         if (plat) {
1049                 i2c->adap.class = plat->class;
1050                 i2c->use_pio = plat->use_pio;
1051                 i2c->fast_mode = plat->fast_mode;
1052         }
1053
1054         if (i2c->use_pio) {
1055                 i2c->adap.algo = &i2c_pxa_pio_algorithm;
1056         } else {
1057                 i2c->adap.algo = &i2c_pxa_algorithm;
1058                 ret = request_irq(irq, i2c_pxa_handler, IRQF_DISABLED,
1059                                   i2c->adap.name, i2c);
1060                 if (ret)
1061                         goto ereqirq;
1062         }
1063
1064         i2c_pxa_reset(i2c);
1065
1066         i2c->adap.algo_data = i2c;
1067         i2c->adap.dev.parent = &dev->dev;
1068
1069         ret = i2c_add_numbered_adapter(&i2c->adap);
1070         if (ret < 0) {
1071                 printk(KERN_INFO "I2C: Failed to add bus\n");
1072                 goto eadapt;
1073         }
1074
1075         platform_set_drvdata(dev, i2c);
1076
1077 #ifdef CONFIG_I2C_PXA_SLAVE
1078         printk(KERN_INFO "I2C: %s: PXA I2C adapter, slave address %d\n",
1079                dev_name(&i2c->adap.dev), i2c->slave_addr);
1080 #else
1081         printk(KERN_INFO "I2C: %s: PXA I2C adapter\n",
1082                dev_name(&i2c->adap.dev));
1083 #endif
1084         return 0;
1085
1086 eadapt:
1087         if (!i2c->use_pio)
1088                 free_irq(irq, i2c);
1089 ereqirq:
1090         clk_disable(i2c->clk);
1091         iounmap(i2c->reg_base);
1092 eremap:
1093         clk_put(i2c->clk);
1094 eclk:
1095         kfree(i2c);
1096 emalloc:
1097         release_mem_region(res->start, res_len(res));
1098         return ret;
1099 }
1100
1101 static int __exit i2c_pxa_remove(struct platform_device *dev)
1102 {
1103         struct pxa_i2c *i2c = platform_get_drvdata(dev);
1104
1105         platform_set_drvdata(dev, NULL);
1106
1107         i2c_del_adapter(&i2c->adap);
1108         if (!i2c->use_pio)
1109                 free_irq(i2c->irq, i2c);
1110
1111         clk_disable(i2c->clk);
1112         clk_put(i2c->clk);
1113
1114         iounmap(i2c->reg_base);
1115         release_mem_region(i2c->iobase, i2c->iosize);
1116         kfree(i2c);
1117
1118         return 0;
1119 }
1120
1121 #ifdef CONFIG_PM
1122 static int i2c_pxa_suspend_late(struct platform_device *dev, pm_message_t state)
1123 {
1124         struct pxa_i2c *i2c = platform_get_drvdata(dev);
1125         clk_disable(i2c->clk);
1126         return 0;
1127 }
1128
1129 static int i2c_pxa_resume_early(struct platform_device *dev)
1130 {
1131         struct pxa_i2c *i2c = platform_get_drvdata(dev);
1132
1133         clk_enable(i2c->clk);
1134         i2c_pxa_reset(i2c);
1135
1136         return 0;
1137 }
1138 #else
1139 #define i2c_pxa_suspend_late NULL
1140 #define i2c_pxa_resume_early NULL
1141 #endif
1142
1143 static struct platform_driver i2c_pxa_driver = {
1144         .probe          = i2c_pxa_probe,
1145         .remove         = __exit_p(i2c_pxa_remove),
1146         .suspend_late   = i2c_pxa_suspend_late,
1147         .resume_early   = i2c_pxa_resume_early,
1148         .driver         = {
1149                 .name   = "pxa2xx-i2c",
1150                 .owner  = THIS_MODULE,
1151         },
1152 };
1153
1154 static int __init i2c_adap_pxa_init(void)
1155 {
1156         return platform_driver_register(&i2c_pxa_driver);
1157 }
1158
1159 static void __exit i2c_adap_pxa_exit(void)
1160 {
1161         platform_driver_unregister(&i2c_pxa_driver);
1162 }
1163
1164 MODULE_LICENSE("GPL");
1165 MODULE_ALIAS("platform:pxa2xx-i2c");
1166
1167 subsys_initcall(i2c_adap_pxa_init);
1168 module_exit(i2c_adap_pxa_exit);