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 separated 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 #include <linux/slab.h>
  37 #include <linux/io.h>
  38
  39 #include <asm/irq.h>
  40 #include <plat/i2c.h>
  41
  42 /*
  43  * I2C register offsets will be shifted 0 or 1 bit left, depending on
  44  * different SoCs
  45  */
  46 #define REG_SHIFT_0     (0 << 0)
  47 #define REG_SHIFT_1     (1 << 0)
  48 #define REG_SHIFT(d)    ((d) & 0x1)
  49
  50 static const struct platform_device_id i2c_pxa_id_table[] = {
  51         { "pxa2xx-i2c",         REG_SHIFT_1 },
  52         { "pxa3xx-pwri2c",      REG_SHIFT_0 },
  53         { },
  54 };
  55 MODULE_DEVICE_TABLE(platform, i2c_pxa_id_table);
  56
  57 /*
  58  * I2C registers and bit definitions
  59  */
  60 #define IBMR            (0x00)
  61 #define IDBR            (0x08)
  62 #define ICR             (0x10)
  63 #define ISR             (0x18)
  64 #define ISAR            (0x20)
  65
  66 #define ICR_START       (1 << 0)           /* start bit */
  67 #define ICR_STOP        (1 << 1)           /* stop bit */
  68 #define ICR_ACKNAK      (1 << 2)           /* send ACK(0) or NAK(1) */
  69 #define ICR_TB          (1 << 3)           /* transfer byte bit */
  70 #define ICR_MA          (1 << 4)           /* master abort */
  71 #define ICR_SCLE        (1 << 5)           /* master clock enable */
  72 #define ICR_IUE         (1 << 6)           /* unit enable */
  73 #define ICR_GCD         (1 << 7)           /* general call disable */
  74 #define ICR_ITEIE       (1 << 8)           /* enable tx interrupts */
  75 #define ICR_IRFIE       (1 << 9)           /* enable rx interrupts */
  76 #define ICR_BEIE        (1 << 10)          /* enable bus error ints */
  77 #define ICR_SSDIE       (1 << 11)          /* slave STOP detected int enable */
  78 #define ICR_ALDIE       (1 << 12)          /* enable arbitration interrupt */
  79 #define ICR_SADIE       (1 << 13)          /* slave address detected int enable */
  80 #define ICR_UR          (1 << 14)          /* unit reset */
  81 #define ICR_FM          (1 << 15)          /* fast mode */
  82
  83 #define ISR_RWM         (1 << 0)           /* read/write mode */
  84 #define ISR_ACKNAK      (1 << 1)           /* ack/nak status */
  85 #define ISR_UB          (1 << 2)           /* unit busy */
  86 #define ISR_IBB         (1 << 3)           /* bus busy */
  87 #define ISR_SSD         (1 << 4)           /* slave stop detected */
  88 #define ISR_ALD         (1 << 5)           /* arbitration loss detected */
  89 #define ISR_ITE         (1 << 6)           /* tx buffer empty */
  90 #define ISR_IRF         (1 << 7)           /* rx buffer full */
  91 #define ISR_GCAD        (1 << 8)           /* general call address detected */
  92 #define ISR_SAD         (1 << 9)           /* slave address detected */
  93 #define ISR_BED         (1 << 10)          /* bus error no ACK/NAK */
  94
  95 struct pxa_i2c {
  96         spinlock_t              lock;
  97         wait_queue_head_t       wait;
  98         struct i2c_msg          *msg;
  99         unsigned int            msg_num;
 100         unsigned int            msg_idx;
 101         unsigned int            msg_ptr;
 102         unsigned int            slave_addr;
 103
 104         struct i2c_adapter      adap;
 105         struct clk              *clk;
 106 #ifdef CONFIG_I2C_PXA_SLAVE
 107         struct i2c_slave_client *slave;
 108 #endif
 109
 110         unsigned int            irqlogidx;
 111         u32                     isrlog[32];
 112         u32                     icrlog[32];
 113
 114         void __iomem            *reg_base;
 115         unsigned int            reg_shift;
 116
 117         unsigned long           iobase;
 118         unsigned long           iosize;
 119
 120         int                     irq;
 121         unsigned int            use_pio :1;
 122         unsigned int            fast_mode :1;
 123 };
 124
 125 #define _IBMR(i2c)      ((i2c)->reg_base + (0x0 << (i2c)->reg_shift))
 126 #define _IDBR(i2c)      ((i2c)->reg_base + (0x4 << (i2c)->reg_shift))
 127 #define _ICR(i2c)       ((i2c)->reg_base + (0x8 << (i2c)->reg_shift))
 128 #define _ISR(i2c)       ((i2c)->reg_base + (0xc << (i2c)->reg_shift))
 129 #define _ISAR(i2c)      ((i2c)->reg_base + (0x10 << (i2c)->reg_shift))
 130
 131 /*
 132  * I2C Slave mode address
 133  */
 134 #define I2C_PXA_SLAVE_ADDR      0x1
 135
 136 #ifdef DEBUG
 137
 138 struct bits {
 139         u32     mask;
 140         const char *set;
 141         const char *unset;
 142 };
 143 #define PXA_BIT(m, s, u)        { .mask = m, .set = s, .unset = u }
 144
 145 static inline void
 146 decode_bits(const char *prefix, const struct bits *bits, int num, u32 val)
 147 {
 148         printk("%s %08x: ", prefix, val);
 149         while (num--) {
 150                 const char *str = val & bits->mask ? bits->set : bits->unset;
 151                 if (str)
 152                         printk("%s ", str);
 153                 bits++;
 154         }
 155 }
 156
 157 static const struct bits isr_bits[] = {
 158         PXA_BIT(ISR_RWM,        "RX",           "TX"),
 159         PXA_BIT(ISR_ACKNAK,     "NAK",          "ACK"),
 160         PXA_BIT(ISR_UB,         "Bsy",          "Rdy"),
 161         PXA_BIT(ISR_IBB,        "BusBsy",       "BusRdy"),
 162         PXA_BIT(ISR_SSD,        "SlaveStop",    NULL),
 163         PXA_BIT(ISR_ALD,        "ALD",          NULL),
 164         PXA_BIT(ISR_ITE,        "TxEmpty",      NULL),
 165         PXA_BIT(ISR_IRF,        "RxFull",       NULL),
 166         PXA_BIT(ISR_GCAD,       "GenCall",      NULL),
 167         PXA_BIT(ISR_SAD,        "SlaveAddr",    NULL),
 168         PXA_BIT(ISR_BED,        "BusErr",       NULL),
 169 };
 170
 171 static void decode_ISR(unsigned int val)
 172 {
 173         decode_bits(KERN_DEBUG "ISR", isr_bits, ARRAY_SIZE(isr_bits), val);
 174         printk("\n");
 175 }
 176
 177 static const struct bits icr_bits[] = {
 178         PXA_BIT(ICR_START,  "START",    NULL),
 179         PXA_BIT(ICR_STOP,   "STOP",     NULL),
 180         PXA_BIT(ICR_ACKNAK, "ACKNAK",   NULL),
 181         PXA_BIT(ICR_TB,     "TB",       NULL),
 182         PXA_BIT(ICR_MA,     "MA",       NULL),
 183         PXA_BIT(ICR_SCLE,   "SCLE",     "scle"),
 184         PXA_BIT(ICR_IUE,    "IUE",      "iue"),
 185         PXA_BIT(ICR_GCD,    "GCD",      NULL),
 186         PXA_BIT(ICR_ITEIE,  "ITEIE",    NULL),
 187         PXA_BIT(ICR_IRFIE,  "IRFIE",    NULL),
 188         PXA_BIT(ICR_BEIE,   "BEIE",     NULL),
 189         PXA_BIT(ICR_SSDIE,  "SSDIE",    NULL),
 190         PXA_BIT(ICR_ALDIE,  "ALDIE",    NULL),
 191         PXA_BIT(ICR_SADIE,  "SADIE",    NULL),
 192         PXA_BIT(ICR_UR,     "UR",               "ur"),
 193 };
 194
 195 #ifdef CONFIG_I2C_PXA_SLAVE
 196 static void decode_ICR(unsigned int val)
 197 {
 198         decode_bits(KERN_DEBUG "ICR", icr_bits, ARRAY_SIZE(icr_bits), val);
 199         printk("\n");
 200 }
 201 #endif
 202
 203 static unsigned int i2c_debug = DEBUG;
 204
 205 static void i2c_pxa_show_state(struct pxa_i2c *i2c, int lno, const char *fname)
 206 {
 207         dev_dbg(&i2c->adap.dev, "state:%s:%d: ISR=%08x, ICR=%08x, IBMR=%02x\n", fname, lno,
 208                 readl(_ISR(i2c)), readl(_ICR(i2c)), readl(_IBMR(i2c)));
 209 }
 210
 211 #define show_state(i2c) i2c_pxa_show_state(i2c, __LINE__, __func__)
 212
 213 static void i2c_pxa_scream_blue_murder(struct pxa_i2c *i2c, const char *why)
 214 {
 215         unsigned int i;
 216         printk(KERN_ERR "i2c: error: %s\n", why);
 217         printk(KERN_ERR "i2c: msg_num: %d msg_idx: %d msg_ptr: %d\n",
 218                 i2c->msg_num, i2c->msg_idx, i2c->msg_ptr);
 219         printk(KERN_ERR "i2c: ICR: %08x ISR: %08x\n",
 220                readl(_ICR(i2c)), readl(_ISR(i2c)));
 221         printk(KERN_DEBUG "i2c: log: ");
 222         for (i = 0; i < i2c->irqlogidx; i++)
 223                 printk("[%08x:%08x] ", i2c->isrlog[i], i2c->icrlog[i]);
 224         printk("\n");
 225 }
 226
 227 #else /* ifdef DEBUG */
 228
 229 #define i2c_debug       0
 230
 231 #define show_state(i2c) do { } while (0)
 232 #define decode_ISR(val) do { } while (0)
 233 #define decode_ICR(val) do { } while (0)
 234 #define i2c_pxa_scream_blue_murder(i2c, why) do { } while (0)
 235
 236 #endif /* ifdef DEBUG / else */
 237
 238 static void i2c_pxa_master_complete(struct pxa_i2c *i2c, int ret);
 239 static irqreturn_t i2c_pxa_handler(int this_irq, void *dev_id);
 240
 241 static inline int i2c_pxa_is_slavemode(struct pxa_i2c *i2c)
 242 {
 243         return !(readl(_ICR(i2c)) & ICR_SCLE);
 244 }
 245
 246 static void i2c_pxa_abort(struct pxa_i2c *i2c)
 247 {
 248         int i = 250;
 249
 250         if (i2c_pxa_is_slavemode(i2c)) {
 251                 dev_dbg(&i2c->adap.dev, "%s: called in slave mode\n", __func__);
 252                 return;
 253         }
 254
 255         while ((i > 0) && (readl(_IBMR(i2c)) & 0x1) == 0) {
 256                 unsigned long icr = readl(_ICR(i2c));
 257
 258                 icr &= ~ICR_START;
 259                 icr |= ICR_ACKNAK | ICR_STOP | ICR_TB;
 260
 261                 writel(icr, _ICR(i2c));
 262
 263                 show_state(i2c);
 264
 265                 mdelay(1);
 266                 i --;
 267         }
 268
 269         writel(readl(_ICR(i2c)) & ~(ICR_MA | ICR_START | ICR_STOP),
 270                _ICR(i2c));
 271 }
 272
 273 static int i2c_pxa_wait_bus_not_busy(struct pxa_i2c *i2c)
 274 {
 275         int timeout = DEF_TIMEOUT;
 276
 277         while (timeout-- && readl(_ISR(i2c)) & (ISR_IBB | ISR_UB)) {
 278                 if ((readl(_ISR(i2c)) & ISR_SAD) != 0)
 279                         timeout += 4;
 280
 281                 msleep(2);
 282                 show_state(i2c);
 283         }
 284
 285         if (timeout < 0)
 286                 show_state(i2c);
 287
 288         return timeout < 0 ? I2C_RETRY : 0;
 289 }
 290
 291 static int i2c_pxa_wait_master(struct pxa_i2c *i2c)
 292 {
 293         unsigned long timeout = jiffies + HZ*4;
 294
 295         while (time_before(jiffies, timeout)) {
 296                 if (i2c_debug > 1)
 297                         dev_dbg(&i2c->adap.dev, "%s: %ld: ISR=%08x, ICR=%08x, IBMR=%02x\n",
 298                                 __func__, (long)jiffies, readl(_ISR(i2c)), readl(_ICR(i2c)), readl(_IBMR(i2c)));
 299
 300                 if (readl(_ISR(i2c)) & ISR_SAD) {
 301                         if (i2c_debug > 0)
 302                                 dev_dbg(&i2c->adap.dev, "%s: Slave detected\n", __func__);
 303                         goto out;
 304                 }
 305
 306                 /* wait for unit and bus being not busy, and we also do a
 307                  * quick check of the i2c lines themselves to ensure they've
 308                  * gone high...
 309                  */
 310                 if ((readl(_ISR(i2c)) & (ISR_UB | ISR_IBB)) == 0 && readl(_IBMR(i2c)) == 3) {
 311                         if (i2c_debug > 0)
 312                                 dev_dbg(&i2c->adap.dev, "%s: done\n", __func__);
 313                         return 1;
 314                 }
 315
 316                 msleep(1);
 317         }
 318
 319         if (i2c_debug > 0)
 320                 dev_dbg(&i2c->adap.dev, "%s: did not free\n", __func__);
 321  out:
 322         return 0;
 323 }
 324
 325 static int i2c_pxa_set_master(struct pxa_i2c *i2c)
 326 {
 327         if (i2c_debug)
 328                 dev_dbg(&i2c->adap.dev, "setting to bus master\n");
 329
 330         if ((readl(_ISR(i2c)) & (ISR_UB | ISR_IBB)) != 0) {
 331                 dev_dbg(&i2c->adap.dev, "%s: unit is busy\n", __func__);
 332                 if (!i2c_pxa_wait_master(i2c)) {
 333                         dev_dbg(&i2c->adap.dev, "%s: error: unit busy\n", __func__);
 334                         return I2C_RETRY;
 335                 }
 336         }
 337
 338         writel(readl(_ICR(i2c)) | ICR_SCLE, _ICR(i2c));
 339         return 0;
 340 }
 341
 342 #ifdef CONFIG_I2C_PXA_SLAVE
 343 static int i2c_pxa_wait_slave(struct pxa_i2c *i2c)
 344 {
 345         unsigned long timeout = jiffies + HZ*1;
 346
 347         /* wait for stop */
 348
 349         show_state(i2c);
 350
 351         while (time_before(jiffies, timeout)) {
 352                 if (i2c_debug > 1)
 353                         dev_dbg(&i2c->adap.dev, "%s: %ld: ISR=%08x, ICR=%08x, IBMR=%02x\n",
 354                                 __func__, (long)jiffies, readl(_ISR(i2c)), readl(_ICR(i2c)), readl(_IBMR(i2c)));
 355
 356                 if ((readl(_ISR(i2c)) & (ISR_UB|ISR_IBB)) == 0 ||
 357                     (readl(_ISR(i2c)) & ISR_SAD) != 0 ||
 358                     (readl(_ICR(i2c)) & ICR_SCLE) == 0) {
 359                         if (i2c_debug > 1)
 360                                 dev_dbg(&i2c->adap.dev, "%s: done\n", __func__);
 361                         return 1;
 362                 }
 363
 364                 msleep(1);
 365         }
 366
 367         if (i2c_debug > 0)
 368                 dev_dbg(&i2c->adap.dev, "%s: did not free\n", __func__);
 369         return 0;
 370 }
 371
 372 /*
 373  * clear the hold on the bus, and take of anything else
 374  * that has been configured
 375  */
 376 static void i2c_pxa_set_slave(struct pxa_i2c *i2c, int errcode)
 377 {
 378         show_state(i2c);
 379
 380         if (errcode < 0) {
 381                 udelay(100);   /* simple delay */
 382         } else {
 383                 /* we need to wait for the stop condition to end */
 384
 385                 /* if we where in stop, then clear... */
 386                 if (readl(_ICR(i2c)) & ICR_STOP) {
 387                         udelay(100);
 388                         writel(readl(_ICR(i2c)) & ~ICR_STOP, _ICR(i2c));
 389                 }
 390
 391                 if (!i2c_pxa_wait_slave(i2c)) {
 392                         dev_err(&i2c->adap.dev, "%s: wait timedout\n",
 393                                 __func__);
 394                         return;
 395                 }
 396         }
 397
 398         writel(readl(_ICR(i2c)) & ~(ICR_STOP|ICR_ACKNAK|ICR_MA), _ICR(i2c));
 399         writel(readl(_ICR(i2c)) & ~ICR_SCLE, _ICR(i2c));
 400
 401         if (i2c_debug) {
 402                 dev_dbg(&i2c->adap.dev, "ICR now %08x, ISR %08x\n", readl(_ICR(i2c)), readl(_ISR(i2c)));
 403                 decode_ICR(readl(_ICR(i2c)));
 404         }
 405 }
 406 #else
 407 #define i2c_pxa_set_slave(i2c, err)     do { } while (0)
 408 #endif
 409
 410 static void i2c_pxa_reset(struct pxa_i2c *i2c)
 411 {
 412         pr_debug("Resetting I2C Controller Unit\n");
 413
 414         /* abort any transfer currently under way */
 415         i2c_pxa_abort(i2c);
 416
 417         /* reset according to 9.8 */
 418         writel(ICR_UR, _ICR(i2c));
 419         writel(I2C_ISR_INIT, _ISR(i2c));
 420         writel(readl(_ICR(i2c)) & ~ICR_UR, _ICR(i2c));
 421
 422         writel(i2c->slave_addr, _ISAR(i2c));
 423
 424         /* set control register values */
 425         writel(I2C_ICR_INIT | (i2c->fast_mode ? ICR_FM : 0), _ICR(i2c));
 426
 427 #ifdef CONFIG_I2C_PXA_SLAVE
 428         dev_info(&i2c->adap.dev, "Enabling slave mode\n");
 429         writel(readl(_ICR(i2c)) | ICR_SADIE | ICR_ALDIE | ICR_SSDIE, _ICR(i2c));
 430 #endif
 431
 432         i2c_pxa_set_slave(i2c, 0);
 433
 434         /* enable unit */
 435         writel(readl(_ICR(i2c)) | ICR_IUE, _ICR(i2c));
 436         udelay(100);
 437 }
 438
 439
 440 #ifdef CONFIG_I2C_PXA_SLAVE
 441 /*
 442  * PXA I2C Slave mode
 443  */
 444
 445 static void i2c_pxa_slave_txempty(struct pxa_i2c *i2c, u32 isr)
 446 {
 447         if (isr & ISR_BED) {
 448                 /* what should we do here? */
 449         } else {
 450                 int ret = 0;
 451
 452                 if (i2c->slave != NULL)
 453                         ret = i2c->slave->read(i2c->slave->data);
 454
 455                 writel(ret, _IDBR(i2c));
 456                 writel(readl(_ICR(i2c)) | ICR_TB, _ICR(i2c));   /* allow next byte */
 457         }
 458 }
 459
 460 static void i2c_pxa_slave_rxfull(struct pxa_i2c *i2c, u32 isr)
 461 {
 462         unsigned int byte = readl(_IDBR(i2c));
 463
 464         if (i2c->slave != NULL)
 465                 i2c->slave->write(i2c->slave->data, byte);
 466
 467         writel(readl(_ICR(i2c)) | ICR_TB, _ICR(i2c));
 468 }
 469
 470 static void i2c_pxa_slave_start(struct pxa_i2c *i2c, u32 isr)
 471 {
 472         int timeout;
 473
 474         if (i2c_debug > 0)
 475                 dev_dbg(&i2c->adap.dev, "SAD, mode is slave-%cx\n",
 476                        (isr & ISR_RWM) ? 'r' : 't');
 477
 478         if (i2c->slave != NULL)
 479                 i2c->slave->event(i2c->slave->data,
 480                                  (isr & ISR_RWM) ? I2C_SLAVE_EVENT_START_READ : I2C_SLAVE_EVENT_START_WRITE);
 481
 482         /*
 483          * slave could interrupt in the middle of us generating a
 484          * start condition... if this happens, we'd better back off
 485          * and stop holding the poor thing up
 486          */
 487         writel(readl(_ICR(i2c)) & ~(ICR_START|ICR_STOP), _ICR(i2c));
 488         writel(readl(_ICR(i2c)) | ICR_TB, _ICR(i2c));
 489
 490         timeout = 0x10000;
 491
 492         while (1) {
 493                 if ((readl(_IBMR(i2c)) & 2) == 2)
 494                         break;
 495
 496                 timeout--;
 497
 498                 if (timeout <= 0) {
 499                         dev_err(&i2c->adap.dev, "timeout waiting for SCL high\n");
 500                         break;
 501                 }
 502         }
 503
 504         writel(readl(_ICR(i2c)) & ~ICR_SCLE, _ICR(i2c));
 505 }
 506
 507 static void i2c_pxa_slave_stop(struct pxa_i2c *i2c)
 508 {
 509         if (i2c_debug > 2)
 510                 dev_dbg(&i2c->adap.dev, "ISR: SSD (Slave Stop)\n");
 511
 512         if (i2c->slave != NULL)
 513                 i2c->slave->event(i2c->slave->data, I2C_SLAVE_EVENT_STOP);
 514
 515         if (i2c_debug > 2)
 516                 dev_dbg(&i2c->adap.dev, "ISR: SSD (Slave Stop) acked\n");
 517
 518         /*
 519          * If we have a master-mode message waiting,
 520          * kick it off now that the slave has completed.
 521          */
 522         if (i2c->msg)
 523                 i2c_pxa_master_complete(i2c, I2C_RETRY);
 524 }
 525 #else
 526 static void i2c_pxa_slave_txempty(struct pxa_i2c *i2c, u32 isr)
 527 {
 528         if (isr & ISR_BED) {
 529                 /* what should we do here? */
 530         } else {
 531                 writel(0, _IDBR(i2c));
 532                 writel(readl(_ICR(i2c)) | ICR_TB, _ICR(i2c));
 533         }
 534 }
 535
 536 static void i2c_pxa_slave_rxfull(struct pxa_i2c *i2c, u32 isr)
 537 {
 538         writel(readl(_ICR(i2c)) | ICR_TB | ICR_ACKNAK, _ICR(i2c));
 539 }
 540
 541 static void i2c_pxa_slave_start(struct pxa_i2c *i2c, u32 isr)
 542 {
 543         int timeout;
 544
 545         /*
 546          * slave could interrupt in the middle of us generating a
 547          * start condition... if this happens, we'd better back off
 548          * and stop holding the poor thing up
 549          */
 550         writel(readl(_ICR(i2c)) & ~(ICR_START|ICR_STOP), _ICR(i2c));
 551         writel(readl(_ICR(i2c)) | ICR_TB | ICR_ACKNAK, _ICR(i2c));
 552
 553         timeout = 0x10000;
 554
 555         while (1) {
 556                 if ((readl(_IBMR(i2c)) & 2) == 2)
 557                         break;
 558
 559                 timeout--;
 560
 561                 if (timeout <= 0) {
 562                         dev_err(&i2c->adap.dev, "timeout waiting for SCL high\n");
 563                         break;
 564                 }
 565         }
 566
 567         writel(readl(_ICR(i2c)) & ~ICR_SCLE, _ICR(i2c));
 568 }
 569
 570 static void i2c_pxa_slave_stop(struct pxa_i2c *i2c)
 571 {
 572         if (i2c->msg)
 573                 i2c_pxa_master_complete(i2c, I2C_RETRY);
 574 }
 575 #endif
 576
 577 /*
 578  * PXA I2C Master mode
 579  */
 580
 581 static inline unsigned int i2c_pxa_addr_byte(struct i2c_msg *msg)
 582 {
 583         unsigned int addr = (msg->addr & 0x7f) << 1;
 584
 585         if (msg->flags & I2C_M_RD)
 586                 addr |= 1;
 587
 588         return addr;
 589 }
 590
 591 static inline void i2c_pxa_start_message(struct pxa_i2c *i2c)
 592 {
 593         u32 icr;
 594
 595         /*
 596          * Step 1: target slave address into IDBR
 597          */
 598         writel(i2c_pxa_addr_byte(i2c->msg), _IDBR(i2c));
 599
 600         /*
 601          * Step 2: initiate the write.
 602          */
 603         icr = readl(_ICR(i2c)) & ~(ICR_STOP | ICR_ALDIE);
 604         writel(icr | ICR_START | ICR_TB, _ICR(i2c));
 605 }
 606
 607 static inline void i2c_pxa_stop_message(struct pxa_i2c *i2c)
 608 {
 609         u32 icr;
 610
 611         /*
 612          * Clear the STOP and ACK flags
 613          */
 614         icr = readl(_ICR(i2c));
 615         icr &= ~(ICR_STOP | ICR_ACKNAK);
 616         writel(icr, _ICR(i2c));
 617 }
 618
 619 static int i2c_pxa_pio_set_master(struct pxa_i2c *i2c)
 620 {
 621         /* make timeout the same as for interrupt based functions */
 622         long timeout = 2 * DEF_TIMEOUT;
 623
 624         /*
 625          * Wait for the bus to become free.
 626          */
 627         while (timeout-- && readl(_ISR(i2c)) & (ISR_IBB | ISR_UB)) {
 628                 udelay(1000);
 629                 show_state(i2c);
 630         }
 631
 632         if (timeout < 0) {
 633                 show_state(i2c);
 634                 dev_err(&i2c->adap.dev,
 635                         "i2c_pxa: timeout waiting for bus free\n");
 636                 return I2C_RETRY;
 637         }
 638
 639         /*
 640          * Set master mode.
 641          */
 642         writel(readl(_ICR(i2c)) | ICR_SCLE, _ICR(i2c));
 643
 644         return 0;
 645 }
 646
 647 static int i2c_pxa_do_pio_xfer(struct pxa_i2c *i2c,
 648                                struct i2c_msg *msg, int num)
 649 {
 650         unsigned long timeout = 500000; /* 5 seconds */
 651         int ret = 0;
 652
 653         ret = i2c_pxa_pio_set_master(i2c);
 654         if (ret)
 655                 goto out;
 656
 657         i2c->msg = msg;
 658         i2c->msg_num = num;
 659         i2c->msg_idx = 0;
 660         i2c->msg_ptr = 0;
 661         i2c->irqlogidx = 0;
 662
 663         i2c_pxa_start_message(i2c);
 664
 665         while (i2c->msg_num > 0 && --timeout) {
 666                 i2c_pxa_handler(0, i2c);
 667                 udelay(10);
 668         }
 669
 670         i2c_pxa_stop_message(i2c);
 671
 672         /*
 673          * We place the return code in i2c->msg_idx.
 674          */
 675         ret = i2c->msg_idx;
 676
 677 out:
 678         if (timeout == 0)
 679                 i2c_pxa_scream_blue_murder(i2c, "timeout");
 680
 681         return ret;
 682 }
 683
 684 /*
 685  * We are protected by the adapter bus mutex.
 686  */
 687 static int i2c_pxa_do_xfer(struct pxa_i2c *i2c, struct i2c_msg *msg, int num)
 688 {
 689         long timeout;
 690         int ret;
 691
 692         /*
 693          * Wait for the bus to become free.
 694          */
 695         ret = i2c_pxa_wait_bus_not_busy(i2c);
 696         if (ret) {
 697                 dev_err(&i2c->adap.dev, "i2c_pxa: timeout waiting for bus free\n");
 698                 goto out;
 699         }
 700
 701         /*
 702          * Set master mode.
 703          */
 704         ret = i2c_pxa_set_master(i2c);
 705         if (ret) {
 706                 dev_err(&i2c->adap.dev, "i2c_pxa_set_master: error %d\n", ret);
 707                 goto out;
 708         }
 709
 710         spin_lock_irq(&i2c->lock);
 711
 712         i2c->msg = msg;
 713         i2c->msg_num = num;
 714         i2c->msg_idx = 0;
 715         i2c->msg_ptr = 0;
 716         i2c->irqlogidx = 0;
 717
 718         i2c_pxa_start_message(i2c);
 719
 720         spin_unlock_irq(&i2c->lock);
 721
 722         /*
 723          * The rest of the processing occurs in the interrupt handler.
 724          */
 725         timeout = wait_event_timeout(i2c->wait, i2c->msg_num == 0, HZ * 5);
 726         i2c_pxa_stop_message(i2c);
 727
 728         /*
 729          * We place the return code in i2c->msg_idx.
 730          */
 731         ret = i2c->msg_idx;
 732
 733         if (timeout == 0)
 734                 i2c_pxa_scream_blue_murder(i2c, "timeout");
 735
 736  out:
 737         return ret;
 738 }
 739
 740 static int i2c_pxa_pio_xfer(struct i2c_adapter *adap,
 741                             struct i2c_msg msgs[], int num)
 742 {
 743         struct pxa_i2c *i2c = adap->algo_data;
 744         int ret, i;
 745
 746         /* If the I2C controller is disabled we need to reset it
 747           (probably due to a suspend/resume destroying state). We do
 748           this here as we can then avoid worrying about resuming the
 749           controller before its users. */
 750         if (!(readl(_ICR(i2c)) & ICR_IUE))
 751                 i2c_pxa_reset(i2c);
 752
 753         for (i = adap->retries; i >= 0; i--) {
 754                 ret = i2c_pxa_do_pio_xfer(i2c, msgs, num);
 755                 if (ret != I2C_RETRY)
 756                         goto out;
 757
 758                 if (i2c_debug)
 759                         dev_dbg(&adap->dev, "Retrying transmission\n");
 760                 udelay(100);
 761         }
 762         i2c_pxa_scream_blue_murder(i2c, "exhausted retries");
 763         ret = -EREMOTEIO;
 764  out:
 765         i2c_pxa_set_slave(i2c, ret);
 766         return ret;
 767 }
 768
 769 /*
 770  * i2c_pxa_master_complete - complete the message and wake up.
 771  */
 772 static void i2c_pxa_master_complete(struct pxa_i2c *i2c, int ret)
 773 {
 774         i2c->msg_ptr = 0;
 775         i2c->msg = NULL;
 776         i2c->msg_idx ++;
 777         i2c->msg_num = 0;
 778         if (ret)
 779                 i2c->msg_idx = ret;
 780         if (!i2c->use_pio)
 781                 wake_up(&i2c->wait);
 782 }
 783
 784 static void i2c_pxa_irq_txempty(struct pxa_i2c *i2c, u32 isr)
 785 {
 786         u32 icr = readl(_ICR(i2c)) & ~(ICR_START|ICR_STOP|ICR_ACKNAK|ICR_TB);
 787
 788  again:
 789         /*
 790          * If ISR_ALD is set, we lost arbitration.
 791          */
 792         if (isr & ISR_ALD) {
 793                 /*
 794                  * Do we need to do anything here?  The PXA docs
 795                  * are vague about what happens.
 796                  */
 797                 i2c_pxa_scream_blue_murder(i2c, "ALD set");
 798
 799                 /*
 800                  * We ignore this error.  We seem to see spurious ALDs
 801                  * for seemingly no reason.  If we handle them as I think
 802                  * they should, we end up causing an I2C error, which
 803                  * is painful for some systems.
 804                  */
 805                 return; /* ignore */
 806         }
 807
 808         if (isr & ISR_BED) {
 809                 int ret = BUS_ERROR;
 810
 811                 /*
 812                  * I2C bus error - either the device NAK'd us, or
 813                  * something more serious happened.  If we were NAK'd
 814                  * on the initial address phase, we can retry.
 815                  */
 816                 if (isr & ISR_ACKNAK) {
 817                         if (i2c->msg_ptr == 0 && i2c->msg_idx == 0)
 818                                 ret = I2C_RETRY;
 819                         else
 820                                 ret = XFER_NAKED;
 821                 }
 822                 i2c_pxa_master_complete(i2c, ret);
 823         } else if (isr & ISR_RWM) {
 824                 /*
 825                  * Read mode.  We have just sent the address byte, and
 826                  * now we must initiate the transfer.
 827                  */
 828                 if (i2c->msg_ptr == i2c->msg->len - 1 &&
 829                     i2c->msg_idx == i2c->msg_num - 1)
 830                         icr |= ICR_STOP | ICR_ACKNAK;
 831
 832                 icr |= ICR_ALDIE | ICR_TB;
 833         } else if (i2c->msg_ptr < i2c->msg->len) {
 834                 /*
 835                  * Write mode.  Write the next data byte.
 836                  */
 837                 writel(i2c->msg->buf[i2c->msg_ptr++], _IDBR(i2c));
 838
 839                 icr |= ICR_ALDIE | ICR_TB;
 840
 841                 /*
 842                  * If this is the last byte of the last message, send
 843                  * a STOP.
 844                  */
 845                 if (i2c->msg_ptr == i2c->msg->len &&
 846                     i2c->msg_idx == i2c->msg_num - 1)
 847                         icr |= ICR_STOP;
 848         } else if (i2c->msg_idx < i2c->msg_num - 1) {
 849                 /*
 850                  * Next segment of the message.
 851                  */
 852                 i2c->msg_ptr = 0;
 853                 i2c->msg_idx ++;
 854                 i2c->msg++;
 855
 856                 /*
 857                  * If we aren't doing a repeated start and address,
 858                  * go back and try to send the next byte.  Note that
 859                  * we do not support switching the R/W direction here.
 860                  */
 861                 if (i2c->msg->flags & I2C_M_NOSTART)
 862                         goto again;
 863
 864                 /*
 865                  * Write the next address.
 866                  */
 867                 writel(i2c_pxa_addr_byte(i2c->msg), _IDBR(i2c));
 868
 869                 /*
 870                  * And trigger a repeated start, and send the byte.
 871                  */
 872                 icr &= ~ICR_ALDIE;
 873                 icr |= ICR_START | ICR_TB;
 874         } else {
 875                 if (i2c->msg->len == 0) {
 876                         /*
 877                          * Device probes have a message length of zero
 878                          * and need the bus to be reset before it can
 879                          * be used again.
 880                          */
 881                         i2c_pxa_reset(i2c);
 882                 }
 883                 i2c_pxa_master_complete(i2c, 0);
 884         }
 885
 886         i2c->icrlog[i2c->irqlogidx-1] = icr;
 887
 888         writel(icr, _ICR(i2c));
 889         show_state(i2c);
 890 }
 891
 892 static void i2c_pxa_irq_rxfull(struct pxa_i2c *i2c, u32 isr)
 893 {
 894         u32 icr = readl(_ICR(i2c)) & ~(ICR_START|ICR_STOP|ICR_ACKNAK|ICR_TB);
 895
 896         /*
 897          * Read the byte.
 898          */
 899         i2c->msg->buf[i2c->msg_ptr++] = readl(_IDBR(i2c));
 900
 901         if (i2c->msg_ptr < i2c->msg->len) {
 902                 /*
 903                  * If this is the last byte of the last
 904                  * message, send a STOP.
 905                  */
 906                 if (i2c->msg_ptr == i2c->msg->len - 1)
 907                         icr |= ICR_STOP | ICR_ACKNAK;
 908
 909                 icr |= ICR_ALDIE | ICR_TB;
 910         } else {
 911                 i2c_pxa_master_complete(i2c, 0);
 912         }
 913
 914         i2c->icrlog[i2c->irqlogidx-1] = icr;
 915
 916         writel(icr, _ICR(i2c));
 917 }
 918
 919 static irqreturn_t i2c_pxa_handler(int this_irq, void *dev_id)
 920 {
 921         struct pxa_i2c *i2c = dev_id;
 922         u32 isr = readl(_ISR(i2c));
 923
 924         if (i2c_debug > 2 && 0) {
 925                 dev_dbg(&i2c->adap.dev, "%s: ISR=%08x, ICR=%08x, IBMR=%02x\n",
 926                         __func__, isr, readl(_ICR(i2c)), readl(_IBMR(i2c)));
 927                 decode_ISR(isr);
 928         }
 929
 930         if (i2c->irqlogidx < ARRAY_SIZE(i2c->isrlog))
 931                 i2c->isrlog[i2c->irqlogidx++] = isr;
 932
 933         show_state(i2c);
 934
 935         /*
 936          * Always clear all pending IRQs.
 937          */
 938         writel(isr & (ISR_SSD|ISR_ALD|ISR_ITE|ISR_IRF|ISR_SAD|ISR_BED), _ISR(i2c));
 939
 940         if (isr & ISR_SAD)
 941                 i2c_pxa_slave_start(i2c, isr);
 942         if (isr & ISR_SSD)
 943                 i2c_pxa_slave_stop(i2c);
 944
 945         if (i2c_pxa_is_slavemode(i2c)) {
 946                 if (isr & ISR_ITE)
 947                         i2c_pxa_slave_txempty(i2c, isr);
 948                 if (isr & ISR_IRF)
 949                         i2c_pxa_slave_rxfull(i2c, isr);
 950         } else if (i2c->msg) {
 951                 if (isr & ISR_ITE)
 952                         i2c_pxa_irq_txempty(i2c, isr);
 953                 if (isr & ISR_IRF)
 954                         i2c_pxa_irq_rxfull(i2c, isr);
 955         } else {
 956                 i2c_pxa_scream_blue_murder(i2c, "spurious irq");
 957         }
 958
 959         return IRQ_HANDLED;
 960 }
 961
 962
 963 static int i2c_pxa_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
 964 {
 965         struct pxa_i2c *i2c = adap->algo_data;
 966         int ret, i;
 967
 968         for (i = adap->retries; i >= 0; i--) {
 969                 ret = i2c_pxa_do_xfer(i2c, msgs, num);
 970                 if (ret != I2C_RETRY)
 971                         goto out;
 972
 973                 if (i2c_debug)
 974                         dev_dbg(&adap->dev, "Retrying transmission\n");
 975                 udelay(100);
 976         }
 977         i2c_pxa_scream_blue_murder(i2c, "exhausted retries");
 978         ret = -EREMOTEIO;
 979  out:
 980         i2c_pxa_set_slave(i2c, ret);
 981         return ret;
 982 }
 983
 984 static u32 i2c_pxa_functionality(struct i2c_adapter *adap)
 985 {
 986         return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
 987 }
 988
 989 static const struct i2c_algorithm i2c_pxa_algorithm = {
 990         .master_xfer    = i2c_pxa_xfer,
 991         .functionality  = i2c_pxa_functionality,
 992 };
 993
 994 static const struct i2c_algorithm i2c_pxa_pio_algorithm = {
 995         .master_xfer    = i2c_pxa_pio_xfer,
 996         .functionality  = i2c_pxa_functionality,
 997 };
 998
 999 static int i2c_pxa_probe(struct platform_device *dev)
1000 {
1001         struct pxa_i2c *i2c;
1002         struct resource *res;
1003         struct i2c_pxa_platform_data *plat = dev->dev.platform_data;
1004         struct platform_device_id *id = platform_get_device_id(dev);
1005         int ret;
1006         int irq;
1007
1008         res = platform_get_resource(dev, IORESOURCE_MEM, 0);
1009         irq = platform_get_irq(dev, 0);
1010         if (res == NULL || irq < 0)
1011                 return -ENODEV;
1012
1013         if (!request_mem_region(res->start, resource_size(res), res->name))
1014                 return -ENOMEM;
1015
1016         i2c = kzalloc(sizeof(struct pxa_i2c), GFP_KERNEL);
1017         if (!i2c) {
1018                 ret = -ENOMEM;
1019                 goto emalloc;
1020         }
1021
1022         i2c->adap.owner   = THIS_MODULE;
1023         i2c->adap.retries = 5;
1024
1025         spin_lock_init(&i2c->lock);
1026         init_waitqueue_head(&i2c->wait);
1027
1028         /*
1029          * If "dev->id" is negative we consider it as zero.
1030          * The reason to do so is to avoid sysfs names that only make
1031          * sense when there are multiple adapters.
1032          */
1033         i2c->adap.nr = dev->id != -1 ? dev->id : 0;
1034         snprintf(i2c->adap.name, sizeof(i2c->adap.name), "pxa_i2c-i2c.%u",
1035                  i2c->adap.nr);
1036
1037         i2c->clk = clk_get(&dev->dev, NULL);
1038         if (IS_ERR(i2c->clk)) {
1039                 ret = PTR_ERR(i2c->clk);
1040                 goto eclk;
1041         }
1042
1043         i2c->reg_base = ioremap(res->start, resource_size(res));
1044         if (!i2c->reg_base) {
1045                 ret = -EIO;
1046                 goto eremap;
1047         }
1048         i2c->reg_shift = REG_SHIFT(id->driver_data);
1049
1050         i2c->iobase = res->start;
1051         i2c->iosize = resource_size(res);
1052
1053         i2c->irq = irq;
1054
1055         i2c->slave_addr = I2C_PXA_SLAVE_ADDR;
1056
1057 #ifdef CONFIG_I2C_PXA_SLAVE
1058         if (plat) {
1059                 i2c->slave_addr = plat->slave_addr;
1060                 i2c->slave = plat->slave;
1061         }
1062 #endif
1063
1064         clk_enable(i2c->clk);
1065
1066         if (plat) {
1067                 i2c->adap.class = plat->class;
1068                 i2c->use_pio = plat->use_pio;
1069                 i2c->fast_mode = plat->fast_mode;
1070         }
1071
1072         if (i2c->use_pio) {
1073                 i2c->adap.algo = &i2c_pxa_pio_algorithm;
1074         } else {
1075                 i2c->adap.algo = &i2c_pxa_algorithm;
1076                 ret = request_irq(irq, i2c_pxa_handler, IRQF_DISABLED,
1077                                   i2c->adap.name, i2c);
1078                 if (ret)
1079                         goto ereqirq;
1080         }
1081
1082         i2c_pxa_reset(i2c);
1083
1084         i2c->adap.algo_data = i2c;
1085         i2c->adap.dev.parent = &dev->dev;
1086
1087         ret = i2c_add_numbered_adapter(&i2c->adap);
1088         if (ret < 0) {
1089                 printk(KERN_INFO "I2C: Failed to add bus\n");
1090                 goto eadapt;
1091         }
1092
1093         platform_set_drvdata(dev, i2c);
1094
1095 #ifdef CONFIG_I2C_PXA_SLAVE
1096         printk(KERN_INFO "I2C: %s: PXA I2C adapter, slave address %d\n",
1097                dev_name(&i2c->adap.dev), i2c->slave_addr);
1098 #else
1099         printk(KERN_INFO "I2C: %s: PXA I2C adapter\n",
1100                dev_name(&i2c->adap.dev));
1101 #endif
1102         return 0;
1103
1104 eadapt:
1105         if (!i2c->use_pio)
1106                 free_irq(irq, i2c);
1107 ereqirq:
1108         clk_disable(i2c->clk);
1109         iounmap(i2c->reg_base);
1110 eremap:
1111         clk_put(i2c->clk);
1112 eclk:
1113         kfree(i2c);
1114 emalloc:
1115         release_mem_region(res->start, resource_size(res));
1116         return ret;
1117 }
1118
1119 static int __exit i2c_pxa_remove(struct platform_device *dev)
1120 {
1121         struct pxa_i2c *i2c = platform_get_drvdata(dev);
1122
1123         platform_set_drvdata(dev, NULL);
1124
1125         i2c_del_adapter(&i2c->adap);
1126         if (!i2c->use_pio)
1127                 free_irq(i2c->irq, i2c);
1128
1129         clk_disable(i2c->clk);
1130         clk_put(i2c->clk);
1131
1132         iounmap(i2c->reg_base);
1133         release_mem_region(i2c->iobase, i2c->iosize);
1134         kfree(i2c);
1135
1136         return 0;
1137 }
1138
1139 #ifdef CONFIG_PM
1140 static int i2c_pxa_suspend_noirq(struct device *dev)
1141 {
1142         struct platform_device *pdev = to_platform_device(dev);
1143         struct pxa_i2c *i2c = platform_get_drvdata(pdev);
1144
1145         clk_disable(i2c->clk);
1146
1147         return 0;
1148 }
1149
1150 static int i2c_pxa_resume_noirq(struct device *dev)
1151 {
1152         struct platform_device *pdev = to_platform_device(dev);
1153         struct pxa_i2c *i2c = platform_get_drvdata(pdev);
1154
1155         clk_enable(i2c->clk);
1156         i2c_pxa_reset(i2c);
1157
1158         return 0;
1159 }
1160
1161 static const struct dev_pm_ops i2c_pxa_dev_pm_ops = {
1162         .suspend_noirq = i2c_pxa_suspend_noirq,
1163         .resume_noirq = i2c_pxa_resume_noirq,
1164 };
1165
1166 #define I2C_PXA_DEV_PM_OPS (&i2c_pxa_dev_pm_ops)
1167 #else
1168 #define I2C_PXA_DEV_PM_OPS NULL
1169 #endif
1170
1171 static struct platform_driver i2c_pxa_driver = {
1172         .probe          = i2c_pxa_probe,
1173         .remove         = __exit_p(i2c_pxa_remove),
1174         .driver         = {
1175                 .name   = "pxa2xx-i2c",
1176                 .owner  = THIS_MODULE,
1177                 .pm     = I2C_PXA_DEV_PM_OPS,
1178         },
1179         .id_table       = i2c_pxa_id_table,
1180 };
1181
1182 static int __init i2c_adap_pxa_init(void)
1183 {
1184         return platform_driver_register(&i2c_pxa_driver);
1185 }
1186
1187 static void __exit i2c_adap_pxa_exit(void)
1188 {
1189         platform_driver_unregister(&i2c_pxa_driver);
1190 }
1191
1192 MODULE_LICENSE("GPL");
1193 MODULE_ALIAS("platform:pxa2xx-i2c");
1194
1195 subsys_initcall(i2c_adap_pxa_init);
1196 module_exit(i2c_adap_pxa_exit);