drivers/i2c/busses/i2c-ibm_iic.c

   1 /*
   2  * drivers/i2c/busses/i2c-ibm_iic.c
   3  *
   4  * Support for the IIC peripheral on IBM PPC 4xx
   5  *
   6  * Copyright (c) 2003, 2004 Zultys Technologies.
   7  * Eugene Surovegin <eugene.surovegin@zultys.com> or <ebs@ebshome.net>
   8  *
   9  * Copyright (c) 2008 PIKA Technologies
  10  * Sean MacLennan <smaclennan@pikatech.com>
  11  *
  12  * Based on original work by
  13  *      Ian DaSilva  <idasilva@mvista.com>
  14  *      Armin Kuster <akuster@mvista.com>
  15  *      Matt Porter  <mporter@mvista.com>
  16  *
  17  *      Copyright 2000-2003 MontaVista Software Inc.
  18  *
  19  * Original driver version was highly leveraged from i2c-elektor.c
  20  *
  21  *      Copyright 1995-97 Simon G. Vogl
  22  *                1998-99 Hans Berglund
  23  *
  24  *      With some changes from Kyösti Mälkki <kmalkki@cc.hut.fi>
  25  *      and even Frodo Looijaard <frodol@dds.nl>
  26  *
  27  * This program is free software; you can redistribute  it and/or modify it
  28  * under  the terms of  the GNU General  Public License as published by the
  29  * Free Software Foundation;  either version 2 of the  License, or (at your
  30  * option) any later version.
  31  *
  32  */
  33
  34 #include <linux/module.h>
  35 #include <linux/kernel.h>
  36 #include <linux/ioport.h>
  37 #include <linux/delay.h>
  38 #include <linux/slab.h>
  39 #include <linux/init.h>
  40 #include <linux/interrupt.h>
  41 #include <asm/irq.h>
  42 #include <linux/io.h>
  43 #include <linux/i2c.h>
  44 #include <linux/of_platform.h>
  45
  46 #include "i2c-ibm_iic.h"
  47
  48 #define DRIVER_VERSION "2.2"
  49
  50 MODULE_DESCRIPTION("IBM IIC driver v" DRIVER_VERSION);
  51 MODULE_LICENSE("GPL");
  52
  53 static bool iic_force_poll;
  54 module_param(iic_force_poll, bool, 0);
  55 MODULE_PARM_DESC(iic_force_poll, "Force polling mode");
  56
  57 static bool iic_force_fast;
  58 module_param(iic_force_fast, bool, 0);
  59 MODULE_PARM_DESC(iic_force_fast, "Force fast mode (400 kHz)");
  60
  61 #define DBG_LEVEL 0
  62
  63 #ifdef DBG
  64 #undef DBG
  65 #endif
  66
  67 #ifdef DBG2
  68 #undef DBG2
  69 #endif
  70
  71 #if DBG_LEVEL > 0
  72 #  define DBG(f,x...)   printk(KERN_DEBUG "ibm-iic" f, ##x)
  73 #else
  74 #  define DBG(f,x...)   ((void)0)
  75 #endif
  76 #if DBG_LEVEL > 1
  77 #  define DBG2(f,x...)  DBG(f, ##x)
  78 #else
  79 #  define DBG2(f,x...)  ((void)0)
  80 #endif
  81 #if DBG_LEVEL > 2
  82 static void dump_iic_regs(const char* header, struct ibm_iic_private* dev)
  83 {
  84         volatile struct iic_regs __iomem *iic = dev->vaddr;
  85         printk(KERN_DEBUG "ibm-iic%d: %s\n", dev->idx, header);
  86         printk(KERN_DEBUG
  87                "  cntl     = 0x%02x, mdcntl = 0x%02x\n"
  88                "  sts      = 0x%02x, extsts = 0x%02x\n"
  89                "  clkdiv   = 0x%02x, xfrcnt = 0x%02x\n"
  90                "  xtcntlss = 0x%02x, directcntl = 0x%02x\n",
  91                 in_8(&iic->cntl), in_8(&iic->mdcntl), in_8(&iic->sts),
  92                 in_8(&iic->extsts), in_8(&iic->clkdiv), in_8(&iic->xfrcnt),
  93                 in_8(&iic->xtcntlss), in_8(&iic->directcntl));
  94 }
  95 #  define DUMP_REGS(h,dev)      dump_iic_regs((h),(dev))
  96 #else
  97 #  define DUMP_REGS(h,dev)      ((void)0)
  98 #endif
  99
 100 /* Bus timings (in ns) for bit-banging */
 101 static struct i2c_timings {
 102         unsigned int hd_sta;
 103         unsigned int su_sto;
 104         unsigned int low;
 105         unsigned int high;
 106         unsigned int buf;
 107 } timings [] = {
 108 /* Standard mode (100 KHz) */
 109 {
 110         .hd_sta = 4000,
 111         .su_sto = 4000,
 112         .low    = 4700,
 113         .high   = 4000,
 114         .buf    = 4700,
 115 },
 116 /* Fast mode (400 KHz) */
 117 {
 118         .hd_sta = 600,
 119         .su_sto = 600,
 120         .low    = 1300,
 121         .high   = 600,
 122         .buf    = 1300,
 123 }};
 124
 125 /* Enable/disable interrupt generation */
 126 static inline void iic_interrupt_mode(struct ibm_iic_private* dev, int enable)
 127 {
 128         out_8(&dev->vaddr->intmsk, enable ? INTRMSK_EIMTC : 0);
 129 }
 130
 131 /*
 132  * Initialize IIC interface.
 133  */
 134 static void iic_dev_init(struct ibm_iic_private* dev)
 135 {
 136         volatile struct iic_regs __iomem *iic = dev->vaddr;
 137
 138         DBG("%d: init\n", dev->idx);
 139
 140         /* Clear master address */
 141         out_8(&iic->lmadr, 0);
 142         out_8(&iic->hmadr, 0);
 143
 144         /* Clear slave address */
 145         out_8(&iic->lsadr, 0);
 146         out_8(&iic->hsadr, 0);
 147
 148         /* Clear status & extended status */
 149         out_8(&iic->sts, STS_SCMP | STS_IRQA);
 150         out_8(&iic->extsts, EXTSTS_IRQP | EXTSTS_IRQD | EXTSTS_LA
 151                             | EXTSTS_ICT | EXTSTS_XFRA);
 152
 153         /* Set clock divider */
 154         out_8(&iic->clkdiv, dev->clckdiv);
 155
 156         /* Clear transfer count */
 157         out_8(&iic->xfrcnt, 0);
 158
 159         /* Clear extended control and status */
 160         out_8(&iic->xtcntlss, XTCNTLSS_SRC | XTCNTLSS_SRS | XTCNTLSS_SWC
 161                             | XTCNTLSS_SWS);
 162
 163         /* Clear control register */
 164         out_8(&iic->cntl, 0);
 165
 166         /* Enable interrupts if possible */
 167         iic_interrupt_mode(dev, dev->irq >= 0);
 168
 169         /* Set mode control */
 170         out_8(&iic->mdcntl, MDCNTL_FMDB | MDCNTL_EINT | MDCNTL_EUBS
 171                             | (dev->fast_mode ? MDCNTL_FSM : 0));
 172
 173         DUMP_REGS("iic_init", dev);
 174 }
 175
 176 /*
 177  * Reset IIC interface
 178  */
 179 static void iic_dev_reset(struct ibm_iic_private* dev)
 180 {
 181         volatile struct iic_regs __iomem *iic = dev->vaddr;
 182         int i;
 183         u8 dc;
 184
 185         DBG("%d: soft reset\n", dev->idx);
 186         DUMP_REGS("reset", dev);
 187
 188         /* Place chip in the reset state */
 189         out_8(&iic->xtcntlss, XTCNTLSS_SRST);
 190
 191         /* Check if bus is free */
 192         dc = in_8(&iic->directcntl);
 193         if (!DIRCTNL_FREE(dc)){
 194                 DBG("%d: trying to regain bus control\n", dev->idx);
 195
 196                 /* Try to set bus free state */
 197                 out_8(&iic->directcntl, DIRCNTL_SDAC | DIRCNTL_SCC);
 198
 199                 /* Wait until we regain bus control */
 200                 for (i = 0; i < 100; ++i){
 201                         dc = in_8(&iic->directcntl);
 202                         if (DIRCTNL_FREE(dc))
 203                                 break;
 204
 205                         /* Toggle SCL line */
 206                         dc ^= DIRCNTL_SCC;
 207                         out_8(&iic->directcntl, dc);
 208                         udelay(10);
 209                         dc ^= DIRCNTL_SCC;
 210                         out_8(&iic->directcntl, dc);
 211
 212                         /* be nice */
 213                         cond_resched();
 214                 }
 215         }
 216
 217         /* Remove reset */
 218         out_8(&iic->xtcntlss, 0);
 219
 220         /* Reinitialize interface */
 221         iic_dev_init(dev);
 222 }
 223
 224 /*
 225  * Do 0-length transaction using bit-banging through IIC_DIRECTCNTL register.
 226  */
 227
 228 /* Wait for SCL and/or SDA to be high */
 229 static int iic_dc_wait(volatile struct iic_regs __iomem *iic, u8 mask)
 230 {
 231         unsigned long x = jiffies + HZ / 28 + 2;
 232         while ((in_8(&iic->directcntl) & mask) != mask){
 233                 if (unlikely(time_after(jiffies, x)))
 234                         return -1;
 235                 cond_resched();
 236         }
 237         return 0;
 238 }
 239
 240 static int iic_smbus_quick(struct ibm_iic_private* dev, const struct i2c_msg* p)
 241 {
 242         volatile struct iic_regs __iomem *iic = dev->vaddr;
 243         const struct i2c_timings* t = &timings[dev->fast_mode ? 1 : 0];
 244         u8 mask, v, sda;
 245         int i, res;
 246
 247         /* Only 7-bit addresses are supported */
 248         if (unlikely(p->flags & I2C_M_TEN)){
 249                 DBG("%d: smbus_quick - 10 bit addresses are not supported\n",
 250                         dev->idx);
 251                 return -EINVAL;
 252         }
 253
 254         DBG("%d: smbus_quick(0x%02x)\n", dev->idx, p->addr);
 255
 256         /* Reset IIC interface */
 257         out_8(&iic->xtcntlss, XTCNTLSS_SRST);
 258
 259         /* Wait for bus to become free */
 260         out_8(&iic->directcntl, DIRCNTL_SDAC | DIRCNTL_SCC);
 261         if (unlikely(iic_dc_wait(iic, DIRCNTL_MSDA | DIRCNTL_MSC)))
 262                 goto err;
 263         ndelay(t->buf);
 264
 265         /* START */
 266         out_8(&iic->directcntl, DIRCNTL_SCC);
 267         sda = 0;
 268         ndelay(t->hd_sta);
 269
 270         /* Send address */
 271         v = (u8)((p->addr << 1) | ((p->flags & I2C_M_RD) ? 1 : 0));
 272         for (i = 0, mask = 0x80; i < 8; ++i, mask >>= 1){
 273                 out_8(&iic->directcntl, sda);
 274                 ndelay(t->low / 2);
 275                 sda = (v & mask) ? DIRCNTL_SDAC : 0;
 276                 out_8(&iic->directcntl, sda);
 277                 ndelay(t->low / 2);
 278
 279                 out_8(&iic->directcntl, DIRCNTL_SCC | sda);
 280                 if (unlikely(iic_dc_wait(iic, DIRCNTL_MSC)))
 281                         goto err;
 282                 ndelay(t->high);
 283         }
 284
 285         /* ACK */
 286         out_8(&iic->directcntl, sda);
 287         ndelay(t->low / 2);
 288         out_8(&iic->directcntl, DIRCNTL_SDAC);
 289         ndelay(t->low / 2);
 290         out_8(&iic->directcntl, DIRCNTL_SDAC | DIRCNTL_SCC);
 291         if (unlikely(iic_dc_wait(iic, DIRCNTL_MSC)))
 292                 goto err;
 293         res = (in_8(&iic->directcntl) & DIRCNTL_MSDA) ? -EREMOTEIO : 1;
 294         ndelay(t->high);
 295
 296         /* STOP */
 297         out_8(&iic->directcntl, 0);
 298         ndelay(t->low);
 299         out_8(&iic->directcntl, DIRCNTL_SCC);
 300         if (unlikely(iic_dc_wait(iic, DIRCNTL_MSC)))
 301                 goto err;
 302         ndelay(t->su_sto);
 303         out_8(&iic->directcntl, DIRCNTL_SDAC | DIRCNTL_SCC);
 304
 305         ndelay(t->buf);
 306
 307         DBG("%d: smbus_quick -> %s\n", dev->idx, res ? "NACK" : "ACK");
 308 out:
 309         /* Remove reset */
 310         out_8(&iic->xtcntlss, 0);
 311
 312         /* Reinitialize interface */
 313         iic_dev_init(dev);
 314
 315         return res;
 316 err:
 317         DBG("%d: smbus_quick - bus is stuck\n", dev->idx);
 318         res = -EREMOTEIO;
 319         goto out;
 320 }
 321
 322 /*
 323  * IIC interrupt handler
 324  */
 325 static irqreturn_t iic_handler(int irq, void *dev_id)
 326 {
 327         struct ibm_iic_private* dev = (struct ibm_iic_private*)dev_id;
 328         volatile struct iic_regs __iomem *iic = dev->vaddr;
 329
 330         DBG2("%d: irq handler, STS = 0x%02x, EXTSTS = 0x%02x\n",
 331              dev->idx, in_8(&iic->sts), in_8(&iic->extsts));
 332
 333         /* Acknowledge IRQ and wakeup iic_wait_for_tc */
 334         out_8(&iic->sts, STS_IRQA | STS_SCMP);
 335         wake_up_interruptible(&dev->wq);
 336
 337         return IRQ_HANDLED;
 338 }
 339
 340 /*
 341  * Get master transfer result and clear errors if any.
 342  * Returns the number of actually transferred bytes or error (<0)
 343  */
 344 static int iic_xfer_result(struct ibm_iic_private* dev)
 345 {
 346         volatile struct iic_regs __iomem *iic = dev->vaddr;
 347
 348         if (unlikely(in_8(&iic->sts) & STS_ERR)){
 349                 DBG("%d: xfer error, EXTSTS = 0x%02x\n", dev->idx,
 350                         in_8(&iic->extsts));
 351
 352                 /* Clear errors and possible pending IRQs */
 353                 out_8(&iic->extsts, EXTSTS_IRQP | EXTSTS_IRQD |
 354                         EXTSTS_LA | EXTSTS_ICT | EXTSTS_XFRA);
 355
 356                 /* Flush master data buffer */
 357                 out_8(&iic->mdcntl, in_8(&iic->mdcntl) | MDCNTL_FMDB);
 358
 359                 /* Is bus free?
 360                  * If error happened during combined xfer
 361                  * IIC interface is usually stuck in some strange
 362                  * state, the only way out - soft reset.
 363                  */
 364                 if ((in_8(&iic->extsts) & EXTSTS_BCS_MASK) != EXTSTS_BCS_FREE){
 365                         DBG("%d: bus is stuck, resetting\n", dev->idx);
 366                         iic_dev_reset(dev);
 367                 }
 368                 return -EREMOTEIO;
 369         }
 370         else
 371                 return in_8(&iic->xfrcnt) & XFRCNT_MTC_MASK;
 372 }
 373
 374 /*
 375  * Try to abort active transfer.
 376  */
 377 static void iic_abort_xfer(struct ibm_iic_private* dev)
 378 {
 379         volatile struct iic_regs __iomem *iic = dev->vaddr;
 380         unsigned long x;
 381
 382         DBG("%d: iic_abort_xfer\n", dev->idx);
 383
 384         out_8(&iic->cntl, CNTL_HMT);
 385
 386         /*
 387          * Wait for the abort command to complete.
 388          * It's not worth to be optimized, just poll (timeout >= 1 tick)
 389          */
 390         x = jiffies + 2;
 391         while ((in_8(&iic->extsts) & EXTSTS_BCS_MASK) != EXTSTS_BCS_FREE){
 392                 if (time_after(jiffies, x)){
 393                         DBG("%d: abort timeout, resetting...\n", dev->idx);
 394                         iic_dev_reset(dev);
 395                         return;
 396                 }
 397                 schedule();
 398         }
 399
 400         /* Just to clear errors */
 401         iic_xfer_result(dev);
 402 }
 403
 404 /*
 405  * Wait for master transfer to complete.
 406  * It puts current process to sleep until we get interrupt or timeout expires.
 407  * Returns the number of transferred bytes or error (<0)
 408  */
 409 static int iic_wait_for_tc(struct ibm_iic_private* dev){
 410
 411         volatile struct iic_regs __iomem *iic = dev->vaddr;
 412         int ret = 0;
 413
 414         if (dev->irq >= 0){
 415                 /* Interrupt mode */
 416                 ret = wait_event_interruptible_timeout(dev->wq,
 417                         !(in_8(&iic->sts) & STS_PT), dev->adap.timeout);
 418
 419                 if (unlikely(ret < 0))
 420                         DBG("%d: wait interrupted\n", dev->idx);
 421                 else if (unlikely(in_8(&iic->sts) & STS_PT)){
 422                         DBG("%d: wait timeout\n", dev->idx);
 423                         ret = -ETIMEDOUT;
 424                 }
 425         }
 426         else {
 427                 /* Polling mode */
 428                 unsigned long x = jiffies + dev->adap.timeout;
 429
 430                 while (in_8(&iic->sts) & STS_PT){
 431                         if (unlikely(time_after(jiffies, x))){
 432                                 DBG("%d: poll timeout\n", dev->idx);
 433                                 ret = -ETIMEDOUT;
 434                                 break;
 435                         }
 436
 437                         if (unlikely(signal_pending(current))){
 438                                 DBG("%d: poll interrupted\n", dev->idx);
 439                                 ret = -ERESTARTSYS;
 440                                 break;
 441                         }
 442                         schedule();
 443                 }
 444         }
 445
 446         if (unlikely(ret < 0))
 447                 iic_abort_xfer(dev);
 448         else
 449                 ret = iic_xfer_result(dev);
 450
 451         DBG2("%d: iic_wait_for_tc -> %d\n", dev->idx, ret);
 452
 453         return ret;
 454 }
 455
 456 /*
 457  * Low level master transfer routine
 458  */
 459 static int iic_xfer_bytes(struct ibm_iic_private* dev, struct i2c_msg* pm,
 460                           int combined_xfer)
 461 {
 462         volatile struct iic_regs __iomem *iic = dev->vaddr;
 463         char* buf = pm->buf;
 464         int i, j, loops, ret = 0;
 465         int len = pm->len;
 466
 467         u8 cntl = (in_8(&iic->cntl) & CNTL_AMD) | CNTL_PT;
 468         if (pm->flags & I2C_M_RD)
 469                 cntl |= CNTL_RW;
 470
 471         loops = (len + 3) / 4;
 472         for (i = 0; i < loops; ++i, len -= 4){
 473                 int count = len > 4 ? 4 : len;
 474                 u8 cmd = cntl | ((count - 1) << CNTL_TCT_SHIFT);
 475
 476                 if (!(cntl & CNTL_RW))
 477                         for (j = 0; j < count; ++j)
 478                                 out_8((void __iomem *)&iic->mdbuf, *buf++);
 479
 480                 if (i < loops - 1)
 481                         cmd |= CNTL_CHT;
 482                 else if (combined_xfer)
 483                         cmd |= CNTL_RPST;
 484
 485                 DBG2("%d: xfer_bytes, %d, CNTL = 0x%02x\n", dev->idx, count, cmd);
 486
 487                 /* Start transfer */
 488                 out_8(&iic->cntl, cmd);
 489
 490                 /* Wait for completion */
 491                 ret = iic_wait_for_tc(dev);
 492
 493                 if (unlikely(ret < 0))
 494                         break;
 495                 else if (unlikely(ret != count)){
 496                         DBG("%d: xfer_bytes, requested %d, transferred %d\n",
 497                                 dev->idx, count, ret);
 498
 499                         /* If it's not a last part of xfer, abort it */
 500                         if (combined_xfer || (i < loops - 1))
 501                                 iic_abort_xfer(dev);
 502
 503                         ret = -EREMOTEIO;
 504                         break;
 505                 }
 506
 507                 if (cntl & CNTL_RW)
 508                         for (j = 0; j < count; ++j)
 509                                 *buf++ = in_8((void __iomem *)&iic->mdbuf);
 510         }
 511
 512         return ret > 0 ? 0 : ret;
 513 }
 514
 515 /*
 516  * Set target slave address for master transfer
 517  */
 518 static inline void iic_address(struct ibm_iic_private* dev, struct i2c_msg* msg)
 519 {
 520         volatile struct iic_regs __iomem *iic = dev->vaddr;
 521         u16 addr = msg->addr;
 522
 523         DBG2("%d: iic_address, 0x%03x (%d-bit)\n", dev->idx,
 524                 addr, msg->flags & I2C_M_TEN ? 10 : 7);
 525
 526         if (msg->flags & I2C_M_TEN){
 527             out_8(&iic->cntl, CNTL_AMD);
 528             out_8(&iic->lmadr, addr);
 529             out_8(&iic->hmadr, 0xf0 | ((addr >> 7) & 0x06));
 530         }
 531         else {
 532             out_8(&iic->cntl, 0);
 533             out_8(&iic->lmadr, addr << 1);
 534         }
 535 }
 536
 537 static inline int iic_invalid_address(const struct i2c_msg* p)
 538 {
 539         return (p->addr > 0x3ff) || (!(p->flags & I2C_M_TEN) && (p->addr > 0x7f));
 540 }
 541
 542 static inline int iic_address_neq(const struct i2c_msg* p1,
 543                                   const struct i2c_msg* p2)
 544 {
 545         return (p1->addr != p2->addr)
 546                 || ((p1->flags & I2C_M_TEN) != (p2->flags & I2C_M_TEN));
 547 }
 548
 549 /*
 550  * Generic master transfer entrypoint.
 551  * Returns the number of processed messages or error (<0)
 552  */
 553 static int iic_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
 554 {
 555         struct ibm_iic_private* dev = (struct ibm_iic_private*)(i2c_get_adapdata(adap));
 556         volatile struct iic_regs __iomem *iic = dev->vaddr;
 557         int i, ret = 0;
 558
 559         DBG2("%d: iic_xfer, %d msg(s)\n", dev->idx, num);
 560
 561         if (!num)
 562                 return 0;
 563
 564         /* Check the sanity of the passed messages.
 565          * Uhh, generic i2c layer is more suitable place for such code...
 566          */
 567         if (unlikely(iic_invalid_address(&msgs[0]))){
 568                 DBG("%d: invalid address 0x%03x (%d-bit)\n", dev->idx,
 569                         msgs[0].addr, msgs[0].flags & I2C_M_TEN ? 10 : 7);
 570                 return -EINVAL;
 571         }
 572         for (i = 0; i < num; ++i){
 573                 if (unlikely(msgs[i].len <= 0)){
 574                         if (num == 1 && !msgs[0].len){
 575                                 /* Special case for I2C_SMBUS_QUICK emulation.
 576                                  * IBM IIC doesn't support 0-length transactions
 577                                  * so we have to emulate them using bit-banging.
 578                                  */
 579                                 return iic_smbus_quick(dev, &msgs[0]);
 580                         }
 581                         DBG("%d: invalid len %d in msg[%d]\n", dev->idx,
 582                                 msgs[i].len, i);
 583                         return -EINVAL;
 584                 }
 585                 if (unlikely(iic_address_neq(&msgs[0], &msgs[i]))){
 586                         DBG("%d: invalid addr in msg[%d]\n", dev->idx, i);
 587                         return -EINVAL;
 588                 }
 589         }
 590
 591         /* Check bus state */
 592         if (unlikely((in_8(&iic->extsts) & EXTSTS_BCS_MASK) != EXTSTS_BCS_FREE)){
 593                 DBG("%d: iic_xfer, bus is not free\n", dev->idx);
 594
 595                 /* Usually it means something serious has happened.
 596                  * We *cannot* have unfinished previous transfer
 597                  * so it doesn't make any sense to try to stop it.
 598                  * Probably we were not able to recover from the
 599                  * previous error.
 600                  * The only *reasonable* thing I can think of here
 601                  * is soft reset.  --ebs
 602                  */
 603                 iic_dev_reset(dev);
 604
 605                 if ((in_8(&iic->extsts) & EXTSTS_BCS_MASK) != EXTSTS_BCS_FREE){
 606                         DBG("%d: iic_xfer, bus is still not free\n", dev->idx);
 607                         return -EREMOTEIO;
 608                 }
 609         }
 610         else {
 611                 /* Flush master data buffer (just in case) */
 612                 out_8(&iic->mdcntl, in_8(&iic->mdcntl) | MDCNTL_FMDB);
 613         }
 614
 615         /* Load slave address */
 616         iic_address(dev, &msgs[0]);
 617
 618         /* Do real transfer */
 619         for (i = 0; i < num && !ret; ++i)
 620                 ret = iic_xfer_bytes(dev, &msgs[i], i < num - 1);
 621
 622         return ret < 0 ? ret : num;
 623 }
 624
 625 static u32 iic_func(struct i2c_adapter *adap)
 626 {
 627         return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_10BIT_ADDR;
 628 }
 629
 630 static const struct i2c_algorithm iic_algo = {
 631         .master_xfer    = iic_xfer,
 632         .functionality  = iic_func
 633 };
 634
 635 /*
 636  * Calculates IICx_CLCKDIV value for a specific OPB clock frequency
 637  */
 638 static inline u8 iic_clckdiv(unsigned int opb)
 639 {
 640         /* Compatibility kludge, should go away after all cards
 641          * are fixed to fill correct value for opbfreq.
 642          * Previous driver version used hardcoded divider value 4,
 643          * it corresponds to OPB frequency from the range (40, 50] MHz
 644          */
 645         if (!opb){
 646                 printk(KERN_WARNING "ibm-iic: using compatibility value for OPB freq,"
 647                         " fix your board specific setup\n");
 648                 opb = 50000000;
 649         }
 650
 651         /* Convert to MHz */
 652         opb /= 1000000;
 653
 654         if (opb < 20 || opb > 150){
 655                 printk(KERN_WARNING "ibm-iic: invalid OPB clock frequency %u MHz\n",
 656                         opb);
 657                 opb = opb < 20 ? 20 : 150;
 658         }
 659         return (u8)((opb + 9) / 10 - 1);
 660 }
 661
 662 static int iic_request_irq(struct platform_device *ofdev,
 663                                      struct ibm_iic_private *dev)
 664 {
 665         struct device_node *np = ofdev->dev.of_node;
 666         int irq;
 667
 668         if (iic_force_poll)
 669                 return 0;
 670
 671         irq = irq_of_parse_and_map(np, 0);
 672         if (!irq) {
 673                 dev_err(&ofdev->dev, "irq_of_parse_and_map failed\n");
 674                 return 0;
 675         }
 676
 677         /* Disable interrupts until we finish initialization, assumes
 678          *  level-sensitive IRQ setup...
 679          */
 680         iic_interrupt_mode(dev, 0);
 681         if (request_irq(irq, iic_handler, 0, "IBM IIC", dev)) {
 682                 dev_err(&ofdev->dev, "request_irq %d failed\n", irq);
 683                 /* Fallback to the polling mode */
 684                 return 0;
 685         }
 686
 687         return irq;
 688 }
 689
 690 /*
 691  * Register single IIC interface
 692  */
 693 static int iic_probe(struct platform_device *ofdev)
 694 {
 695         struct device_node *np = ofdev->dev.of_node;
 696         struct ibm_iic_private *dev;
 697         struct i2c_adapter *adap;
 698         const u32 *freq;
 699         int ret;
 700
 701         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
 702         if (!dev) {
 703                 dev_err(&ofdev->dev, "failed to allocate device data\n");
 704                 return -ENOMEM;
 705         }
 706
 707         platform_set_drvdata(ofdev, dev);
 708
 709         dev->vaddr = of_iomap(np, 0);
 710         if (dev->vaddr == NULL) {
 711                 dev_err(&ofdev->dev, "failed to iomap device\n");
 712                 ret = -ENXIO;
 713                 goto error_cleanup;
 714         }
 715
 716         init_waitqueue_head(&dev->wq);
 717
 718         dev->irq = iic_request_irq(ofdev, dev);
 719         if (!dev->irq)
 720                 dev_warn(&ofdev->dev, "using polling mode\n");
 721
 722         /* Board specific settings */
 723         if (iic_force_fast || of_get_property(np, "fast-mode", NULL))
 724                 dev->fast_mode = 1;
 725
 726         freq = of_get_property(np, "clock-frequency", NULL);
 727         if (freq == NULL) {
 728                 freq = of_get_property(np->parent, "clock-frequency", NULL);
 729                 if (freq == NULL) {
 730                         dev_err(&ofdev->dev, "Unable to get bus frequency\n");
 731                         ret = -EINVAL;
 732                         goto error_cleanup;
 733                 }
 734         }
 735
 736         dev->clckdiv = iic_clckdiv(*freq);
 737         dev_dbg(&ofdev->dev, "clckdiv = %d\n", dev->clckdiv);
 738
 739         /* Initialize IIC interface */
 740         iic_dev_init(dev);
 741
 742         /* Register it with i2c layer */
 743         adap = &dev->adap;
 744         adap->dev.parent = &ofdev->dev;
 745         adap->dev.of_node = of_node_get(np);
 746         strlcpy(adap->name, "IBM IIC", sizeof(adap->name));
 747         i2c_set_adapdata(adap, dev);
 748         adap->class = I2C_CLASS_HWMON | I2C_CLASS_SPD;
 749         adap->algo = &iic_algo;
 750         adap->timeout = HZ;
 751
 752         ret = i2c_add_adapter(adap);
 753         if (ret  < 0) {
 754                 dev_err(&ofdev->dev, "failed to register i2c adapter\n");
 755                 goto error_cleanup;
 756         }
 757
 758         dev_info(&ofdev->dev, "using %s mode\n",
 759                  dev->fast_mode ? "fast (400 kHz)" : "standard (100 kHz)");
 760
 761         return 0;
 762
 763 error_cleanup:
 764         if (dev->irq) {
 765                 iic_interrupt_mode(dev, 0);
 766                 free_irq(dev->irq, dev);
 767         }
 768
 769         if (dev->vaddr)
 770                 iounmap(dev->vaddr);
 771
 772         kfree(dev);
 773         return ret;
 774 }
 775
 776 /*
 777  * Cleanup initialized IIC interface
 778  */
 779 static int iic_remove(struct platform_device *ofdev)
 780 {
 781         struct ibm_iic_private *dev = platform_get_drvdata(ofdev);
 782
 783         i2c_del_adapter(&dev->adap);
 784
 785         if (dev->irq) {
 786                 iic_interrupt_mode(dev, 0);
 787                 free_irq(dev->irq, dev);
 788         }
 789
 790         iounmap(dev->vaddr);
 791         kfree(dev);
 792
 793         return 0;
 794 }
 795
 796 static const struct of_device_id ibm_iic_match[] = {
 797         { .compatible = "ibm,iic", },
 798         {}
 799 };
 800
 801 static struct platform_driver ibm_iic_driver = {
 802         .driver = {
 803                 .name = "ibm-iic",
 804                 .owner = THIS_MODULE,
 805                 .of_match_table = ibm_iic_match,
 806         },
 807         .probe  = iic_probe,
 808         .remove = iic_remove,
 809 };
 810
 811 module_platform_driver(ibm_iic_driver);