drivers/i2c/busses/i2c-s3c2410.c

   1 /* linux/drivers/i2c/busses/i2c-s3c2410.c
   2  *
   3  * Copyright (C) 2004,2005 Simtec Electronics
   4  *      Ben Dooks <ben@simtec.co.uk>
   5  *
   6  * S3C2410 I2C Controller
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation; either version 2 of the License, or
  11  * (at your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program; if not, write to the Free Software
  20  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  21 */
  22
  23 #include <linux/config.h>
  24 #include <linux/kernel.h>
  25 #include <linux/module.h>
  26
  27 #include <linux/i2c.h>
  28 #include <linux/i2c-id.h>
  29 #include <linux/init.h>
  30 #include <linux/time.h>
  31 #include <linux/interrupt.h>
  32 #include <linux/sched.h>
  33 #include <linux/delay.h>
  34 #include <linux/errno.h>
  35 #include <linux/err.h>
  36 #include <linux/device.h>
  37
  38 #include <asm/hardware.h>
  39 #include <asm/irq.h>
  40 #include <asm/io.h>
  41
  42 #include <asm/hardware/clock.h>
  43 #include <asm/arch/regs-gpio.h>
  44 #include <asm/arch/regs-iic.h>
  45 #include <asm/arch/iic.h>
  46
  47 /* i2c controller state */
  48
  49 enum s3c24xx_i2c_state {
  50         STATE_IDLE,
  51         STATE_START,
  52         STATE_READ,
  53         STATE_WRITE,
  54         STATE_STOP
  55 };
  56
  57 struct s3c24xx_i2c {
  58         spinlock_t              lock;
  59         wait_queue_head_t       wait;
  60
  61         struct i2c_msg          *msg;
  62         unsigned int            msg_num;
  63         unsigned int            msg_idx;
  64         unsigned int            msg_ptr;
  65
  66         enum s3c24xx_i2c_state  state;
  67
  68         void __iomem            *regs;
  69         struct clk              *clk;
  70         struct device           *dev;
  71         struct resource         *irq;
  72         struct resource         *ioarea;
  73         struct i2c_adapter      adap;
  74 };
  75
  76 /* default platform data to use if not supplied in the platform_device
  77 */
  78
  79 static struct s3c2410_platform_i2c s3c24xx_i2c_default_platform = {
  80         .flags          = 0,
  81         .slave_addr     = 0x10,
  82         .bus_freq       = 100*1000,
  83         .max_freq       = 400*1000,
  84         .sda_delay      = S3C2410_IICLC_SDA_DELAY5 | S3C2410_IICLC_FILTER_ON,
  85 };
  86
  87 /* s3c24xx_i2c_is2440()
  88  *
  89  * return true is this is an s3c2440
  90 */
  91
  92 static inline int s3c24xx_i2c_is2440(struct s3c24xx_i2c *i2c)
  93 {
  94         struct platform_device *pdev = to_platform_device(i2c->dev);
  95
  96         return !strcmp(pdev->name, "s3c2440-i2c");
  97 }
  98
  99
 100 /* s3c24xx_i2c_get_platformdata
 101  *
 102  * get the platform data associated with the given device, or return
 103  * the default if there is none
 104 */
 105
 106 static inline struct s3c2410_platform_i2c *s3c24xx_i2c_get_platformdata(struct device *dev)
 107 {
 108         if (dev->platform_data != NULL)
 109                 return (struct s3c2410_platform_i2c *)dev->platform_data;
 110
 111         return &s3c24xx_i2c_default_platform;
 112 }
 113
 114 /* s3c24xx_i2c_master_complete
 115  *
 116  * complete the message and wake up the caller, using the given return code,
 117  * or zero to mean ok.
 118 */
 119
 120 static inline void s3c24xx_i2c_master_complete(struct s3c24xx_i2c *i2c, int ret)
 121 {
 122         dev_dbg(i2c->dev, "master_complete %d\n", ret);
 123
 124         i2c->msg_ptr = 0;
 125         i2c->msg = NULL;
 126         i2c->msg_idx ++;
 127         i2c->msg_num = 0;
 128         if (ret)
 129                 i2c->msg_idx = ret;
 130
 131         wake_up(&i2c->wait);
 132 }
 133
 134 static inline void s3c24xx_i2c_disable_ack(struct s3c24xx_i2c *i2c)
 135 {
 136         unsigned long tmp;
 137
 138         tmp = readl(i2c->regs + S3C2410_IICCON);
 139         writel(tmp & ~S3C2410_IICCON_ACKEN, i2c->regs + S3C2410_IICCON);
 140
 141 }
 142
 143 static inline void s3c24xx_i2c_enable_ack(struct s3c24xx_i2c *i2c)
 144 {
 145         unsigned long tmp;
 146
 147         tmp = readl(i2c->regs + S3C2410_IICCON);
 148         writel(tmp | S3C2410_IICCON_ACKEN, i2c->regs + S3C2410_IICCON);
 149
 150 }
 151
 152 /* irq enable/disable functions */
 153
 154 static inline void s3c24xx_i2c_disable_irq(struct s3c24xx_i2c *i2c)
 155 {
 156         unsigned long tmp;
 157
 158         tmp = readl(i2c->regs + S3C2410_IICCON);
 159         writel(tmp & ~S3C2410_IICCON_IRQEN, i2c->regs + S3C2410_IICCON);
 160 }
 161
 162 static inline void s3c24xx_i2c_enable_irq(struct s3c24xx_i2c *i2c)
 163 {
 164         unsigned long tmp;
 165
 166         tmp = readl(i2c->regs + S3C2410_IICCON);
 167         writel(tmp | S3C2410_IICCON_IRQEN, i2c->regs + S3C2410_IICCON);
 168 }
 169
 170
 171 /* s3c24xx_i2c_message_start
 172  *
 173  * put the start of a message onto the bus
 174 */
 175
 176 static void s3c24xx_i2c_message_start(struct s3c24xx_i2c *i2c,
 177                                       struct i2c_msg *msg)
 178 {
 179         unsigned int addr = (msg->addr & 0x7f) << 1;
 180         unsigned long stat;
 181         unsigned long iiccon;
 182
 183         stat = 0;
 184         stat |=  S3C2410_IICSTAT_TXRXEN;
 185
 186         if (msg->flags & I2C_M_RD) {
 187                 stat |= S3C2410_IICSTAT_MASTER_RX;
 188                 addr |= 1;
 189         } else
 190                 stat |= S3C2410_IICSTAT_MASTER_TX;
 191
 192         if (msg->flags & I2C_M_REV_DIR_ADDR)
 193                 addr ^= 1;
 194
 195         // todo - check for wether ack wanted or not
 196         s3c24xx_i2c_enable_ack(i2c);
 197
 198         iiccon = readl(i2c->regs + S3C2410_IICCON);
 199         writel(stat, i2c->regs + S3C2410_IICSTAT);
 200
 201         dev_dbg(i2c->dev, "START: %08lx to IICSTAT, %02x to DS\n", stat, addr);
 202         writeb(addr, i2c->regs + S3C2410_IICDS);
 203
 204         // delay a bit and reset iiccon before setting start (per samsung)
 205         udelay(1);
 206         dev_dbg(i2c->dev, "iiccon, %08lx\n", iiccon);
 207         writel(iiccon, i2c->regs + S3C2410_IICCON);
 208
 209         stat |=  S3C2410_IICSTAT_START;
 210         writel(stat, i2c->regs + S3C2410_IICSTAT);
 211 }
 212
 213 static inline void s3c24xx_i2c_stop(struct s3c24xx_i2c *i2c, int ret)
 214 {
 215         unsigned long iicstat = readl(i2c->regs + S3C2410_IICSTAT);
 216
 217         dev_dbg(i2c->dev, "STOP\n");
 218
 219         /* stop the transfer */
 220         iicstat &= ~ S3C2410_IICSTAT_START;
 221         writel(iicstat, i2c->regs + S3C2410_IICSTAT);
 222
 223         i2c->state = STATE_STOP;
 224
 225         s3c24xx_i2c_master_complete(i2c, ret);
 226         s3c24xx_i2c_disable_irq(i2c);
 227 }
 228
 229 /* helper functions to determine the current state in the set of
 230  * messages we are sending */
 231
 232 /* is_lastmsg()
 233  *
 234  * returns TRUE if the current message is the last in the set
 235 */
 236
 237 static inline int is_lastmsg(struct s3c24xx_i2c *i2c)
 238 {
 239         return i2c->msg_idx >= (i2c->msg_num - 1);
 240 }
 241
 242 /* is_msglast
 243  *
 244  * returns TRUE if we this is the last byte in the current message
 245 */
 246
 247 static inline int is_msglast(struct s3c24xx_i2c *i2c)
 248 {
 249         return i2c->msg_ptr == i2c->msg->len-1;
 250 }
 251
 252 /* is_msgend
 253  *
 254  * returns TRUE if we reached the end of the current message
 255 */
 256
 257 static inline int is_msgend(struct s3c24xx_i2c *i2c)
 258 {
 259         return i2c->msg_ptr >= i2c->msg->len;
 260 }
 261
 262 /* i2s_s3c_irq_nextbyte
 263  *
 264  * process an interrupt and work out what to do
 265  */
 266
 267 static int i2s_s3c_irq_nextbyte(struct s3c24xx_i2c *i2c, unsigned long iicstat)
 268 {
 269         unsigned long tmp;
 270         unsigned char byte;
 271         int ret = 0;
 272
 273         switch (i2c->state) {
 274
 275         case STATE_IDLE:
 276                 dev_err(i2c->dev, "%s: called in STATE_IDLE\n", __FUNCTION__);
 277                 goto out;
 278                 break;
 279
 280         case STATE_STOP:
 281                 dev_err(i2c->dev, "%s: called in STATE_STOP\n", __FUNCTION__);
 282                 s3c24xx_i2c_disable_irq(i2c);
 283                 goto out_ack;
 284
 285         case STATE_START:
 286                 /* last thing we did was send a start condition on the
 287                  * bus, or started a new i2c message
 288                  */
 289
 290                 if (iicstat  & S3C2410_IICSTAT_LASTBIT &&
 291                     !(i2c->msg->flags & I2C_M_IGNORE_NAK)) {
 292                         /* ack was not received... */
 293
 294                         dev_dbg(i2c->dev, "ack was not received\n");
 295                         s3c24xx_i2c_stop(i2c, -EREMOTEIO);
 296                         goto out_ack;
 297                 }
 298
 299                 if (i2c->msg->flags & I2C_M_RD)
 300                         i2c->state = STATE_READ;
 301                 else
 302                         i2c->state = STATE_WRITE;
 303
 304                 /* terminate the transfer if there is nothing to do
 305                  * (used by the i2c probe to find devices */
 306
 307                 if (is_lastmsg(i2c) && i2c->msg->len == 0) {
 308                         s3c24xx_i2c_stop(i2c, 0);
 309                         goto out_ack;
 310                 }
 311
 312                 if (i2c->state == STATE_READ)
 313                         goto prepare_read;
 314
 315                 /* fall through to the write state, as we will need to
 316                  * send a byte as well */
 317
 318         case STATE_WRITE:
 319                 /* we are writing data to the device... check for the
 320                  * end of the message, and if so, work out what to do
 321                  */
 322
 323         retry_write:
 324                 if (!is_msgend(i2c)) {
 325                         byte = i2c->msg->buf[i2c->msg_ptr++];
 326                         writeb(byte, i2c->regs + S3C2410_IICDS);
 327
 328                 } else if (!is_lastmsg(i2c)) {
 329                         /* we need to go to the next i2c message */
 330
 331                         dev_dbg(i2c->dev, "WRITE: Next Message\n");
 332
 333                         i2c->msg_ptr = 0;
 334                         i2c->msg_idx ++;
 335                         i2c->msg++;
 336
 337                         /* check to see if we need to do another message */
 338                         if (i2c->msg->flags & I2C_M_NOSTART) {
 339
 340                                 if (i2c->msg->flags & I2C_M_RD) {
 341                                         /* cannot do this, the controller
 342                                          * forces us to send a new START
 343                                          * when we change direction */
 344
 345                                         s3c24xx_i2c_stop(i2c, -EINVAL);
 346                                 }
 347
 348                                 goto retry_write;
 349                         } else {
 350
 351                                 /* send the new start */
 352                                 s3c24xx_i2c_message_start(i2c, i2c->msg);
 353                                 i2c->state = STATE_START;
 354                         }
 355
 356                 } else {
 357                         /* send stop */
 358
 359                         s3c24xx_i2c_stop(i2c, 0);
 360                 }
 361                 break;
 362
 363         case STATE_READ:
 364                 /* we have a byte of data in the data register, do
 365                  * something with it, and then work out wether we are
 366                  * going to do any more read/write
 367                  */
 368
 369                 if (!(i2c->msg->flags & I2C_M_IGNORE_NAK) &&
 370                     !(is_msglast(i2c) && is_lastmsg(i2c))) {
 371
 372                         if (iicstat & S3C2410_IICSTAT_LASTBIT) {
 373                                 dev_dbg(i2c->dev, "READ: No Ack\n");
 374
 375                                 s3c24xx_i2c_stop(i2c, -ECONNREFUSED);
 376                                 goto out_ack;
 377                         }
 378                 }
 379
 380                 byte = readb(i2c->regs + S3C2410_IICDS);
 381                 i2c->msg->buf[i2c->msg_ptr++] = byte;
 382
 383         prepare_read:
 384                 if (is_msglast(i2c)) {
 385                         /* last byte of buffer */
 386
 387                         if (is_lastmsg(i2c))
 388                                 s3c24xx_i2c_disable_ack(i2c);
 389
 390                 } else if (is_msgend(i2c)) {
 391                         /* ok, we've read the entire buffer, see if there
 392                          * is anything else we need to do */
 393
 394                         if (is_lastmsg(i2c)) {
 395                                 /* last message, send stop and complete */
 396                                 dev_dbg(i2c->dev, "READ: Send Stop\n");
 397
 398                                 s3c24xx_i2c_stop(i2c, 0);
 399                         } else {
 400                                 /* go to the next transfer */
 401                                 dev_dbg(i2c->dev, "READ: Next Transfer\n");
 402
 403                                 i2c->msg_ptr = 0;
 404                                 i2c->msg_idx++;
 405                                 i2c->msg++;
 406                         }
 407                 }
 408
 409                 break;
 410         }
 411
 412         /* acknowlegde the IRQ and get back on with the work */
 413
 414  out_ack:
 415         tmp = readl(i2c->regs + S3C2410_IICCON);
 416         tmp &= ~S3C2410_IICCON_IRQPEND;
 417         writel(tmp, i2c->regs + S3C2410_IICCON);
 418  out:
 419         return ret;
 420 }
 421
 422 /* s3c24xx_i2c_irq
 423  *
 424  * top level IRQ servicing routine
 425 */
 426
 427 static irqreturn_t s3c24xx_i2c_irq(int irqno, void *dev_id,
 428                                    struct pt_regs *regs)
 429 {
 430         struct s3c24xx_i2c *i2c = dev_id;
 431         unsigned long status;
 432         unsigned long tmp;
 433
 434         status = readl(i2c->regs + S3C2410_IICSTAT);
 435
 436         if (status & S3C2410_IICSTAT_ARBITR) {
 437                 // deal with arbitration loss
 438                 dev_err(i2c->dev, "deal with arbitration loss\n");
 439         }
 440
 441         if (i2c->state == STATE_IDLE) {
 442                 dev_dbg(i2c->dev, "IRQ: error i2c->state == IDLE\n");
 443
 444                 tmp = readl(i2c->regs + S3C2410_IICCON);
 445                 tmp &= ~S3C2410_IICCON_IRQPEND;
 446                 writel(tmp, i2c->regs +  S3C2410_IICCON);
 447                 goto out;
 448         }
 449
 450         /* pretty much this leaves us with the fact that we've
 451          * transmitted or received whatever byte we last sent */
 452
 453         i2s_s3c_irq_nextbyte(i2c, status);
 454
 455  out:
 456         return IRQ_HANDLED;
 457 }
 458
 459
 460 /* s3c24xx_i2c_set_master
 461  *
 462  * get the i2c bus for a master transaction
 463 */
 464
 465 static int s3c24xx_i2c_set_master(struct s3c24xx_i2c *i2c)
 466 {
 467         unsigned long iicstat;
 468         int timeout = 400;
 469
 470         while (timeout-- > 0) {
 471                 iicstat = readl(i2c->regs + S3C2410_IICSTAT);
 472
 473                 if (!(iicstat & S3C2410_IICSTAT_BUSBUSY))
 474                         return 0;
 475
 476                 msleep(1);
 477         }
 478
 479         dev_dbg(i2c->dev, "timeout: GPEDAT is %08x\n",
 480                 __raw_readl(S3C2410_GPEDAT));
 481
 482         return -ETIMEDOUT;
 483 }
 484
 485 /* s3c24xx_i2c_doxfer
 486  *
 487  * this starts an i2c transfer
 488 */
 489
 490 static int s3c24xx_i2c_doxfer(struct s3c24xx_i2c *i2c, struct i2c_msg *msgs, int num)
 491 {
 492         unsigned long timeout;
 493         int ret;
 494
 495         ret = s3c24xx_i2c_set_master(i2c);
 496         if (ret != 0) {
 497                 dev_err(i2c->dev, "cannot get bus (error %d)\n", ret);
 498                 ret = -EAGAIN;
 499                 goto out;
 500         }
 501
 502         spin_lock_irq(&i2c->lock);
 503
 504         i2c->msg     = msgs;
 505         i2c->msg_num = num;
 506         i2c->msg_ptr = 0;
 507         i2c->msg_idx = 0;
 508         i2c->state   = STATE_START;
 509
 510         s3c24xx_i2c_enable_irq(i2c);
 511         s3c24xx_i2c_message_start(i2c, msgs);
 512         spin_unlock_irq(&i2c->lock);
 513
 514         timeout = wait_event_timeout(i2c->wait, i2c->msg_num == 0, HZ * 5);
 515
 516         ret = i2c->msg_idx;
 517
 518         /* having these next two as dev_err() makes life very
 519          * noisy when doing an i2cdetect */
 520
 521         if (timeout == 0)
 522                 dev_dbg(i2c->dev, "timeout\n");
 523         else if (ret != num)
 524                 dev_dbg(i2c->dev, "incomplete xfer (%d)\n", ret);
 525
 526         /* ensure the stop has been through the bus */
 527
 528         msleep(1);
 529
 530  out:
 531         return ret;
 532 }
 533
 534 /* s3c24xx_i2c_xfer
 535  *
 536  * first port of call from the i2c bus code when an message needs
 537  * transferring across the i2c bus.
 538 */
 539
 540 static int s3c24xx_i2c_xfer(struct i2c_adapter *adap,
 541                         struct i2c_msg *msgs, int num)
 542 {
 543         struct s3c24xx_i2c *i2c = (struct s3c24xx_i2c *)adap->algo_data;
 544         int retry;
 545         int ret;
 546
 547         for (retry = 0; retry < adap->retries; retry++) {
 548
 549                 ret = s3c24xx_i2c_doxfer(i2c, msgs, num);
 550
 551                 if (ret != -EAGAIN)
 552                         return ret;
 553
 554                 dev_dbg(i2c->dev, "Retrying transmission (%d)\n", retry);
 555
 556                 udelay(100);
 557         }
 558
 559         return -EREMOTEIO;
 560 }
 561
 562 /* declare our i2c functionality */
 563 static u32 s3c24xx_i2c_func(struct i2c_adapter *adap)
 564 {
 565         return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_PROTOCOL_MANGLING;
 566 }
 567
 568 /* i2c bus registration info */
 569
 570 static struct i2c_algorithm s3c24xx_i2c_algorithm = {
 571         .master_xfer            = s3c24xx_i2c_xfer,
 572         .functionality          = s3c24xx_i2c_func,
 573 };
 574
 575 static struct s3c24xx_i2c s3c24xx_i2c = {
 576         .lock   = SPIN_LOCK_UNLOCKED,
 577         .wait   = __WAIT_QUEUE_HEAD_INITIALIZER(s3c24xx_i2c.wait),
 578         .adap   = {
 579                 .name                   = "s3c2410-i2c",
 580                 .owner                  = THIS_MODULE,
 581                 .algo                   = &s3c24xx_i2c_algorithm,
 582                 .retries                = 2,
 583                 .class                  = I2C_CLASS_HWMON,
 584         },
 585 };
 586
 587 /* s3c24xx_i2c_calcdivisor
 588  *
 589  * return the divisor settings for a given frequency
 590 */
 591
 592 static int s3c24xx_i2c_calcdivisor(unsigned long clkin, unsigned int wanted,
 593                                    unsigned int *div1, unsigned int *divs)
 594 {
 595         unsigned int calc_divs = clkin / wanted;
 596         unsigned int calc_div1;
 597
 598         if (calc_divs > (16*16))
 599                 calc_div1 = 512;
 600         else
 601                 calc_div1 = 16;
 602
 603         calc_divs += calc_div1-1;
 604         calc_divs /= calc_div1;
 605
 606         if (calc_divs == 0)
 607                 calc_divs = 1;
 608         if (calc_divs > 17)
 609                 calc_divs = 17;
 610
 611         *divs = calc_divs;
 612         *div1 = calc_div1;
 613
 614         return clkin / (calc_divs * calc_div1);
 615 }
 616
 617 /* freq_acceptable
 618  *
 619  * test wether a frequency is within the acceptable range of error
 620 */
 621
 622 static inline int freq_acceptable(unsigned int freq, unsigned int wanted)
 623 {
 624         int diff = freq - wanted;
 625
 626         return (diff >= -2 && diff <= 2);
 627 }
 628
 629 /* s3c24xx_i2c_getdivisor
 630  *
 631  * work out a divisor for the user requested frequency setting,
 632  * either by the requested frequency, or scanning the acceptable
 633  * range of frequencies until something is found
 634 */
 635
 636 static int s3c24xx_i2c_getdivisor(struct s3c24xx_i2c *i2c,
 637                                   struct s3c2410_platform_i2c *pdata,
 638                                   unsigned long *iicon,
 639                                   unsigned int *got)
 640 {
 641         unsigned long clkin = clk_get_rate(i2c->clk);
 642
 643         unsigned int divs, div1;
 644         int freq;
 645         int start, end;
 646
 647         clkin /= 1000;          /* clkin now in KHz */
 648
 649         dev_dbg(i2c->dev,  "pdata %p, freq %lu %lu..%lu\n",
 650                  pdata, pdata->bus_freq, pdata->min_freq, pdata->max_freq);
 651
 652         if (pdata->bus_freq != 0) {
 653                 freq = s3c24xx_i2c_calcdivisor(clkin, pdata->bus_freq/1000,
 654                                                &div1, &divs);
 655                 if (freq_acceptable(freq, pdata->bus_freq/1000))
 656                         goto found;
 657         }
 658
 659         /* ok, we may have to search for something suitable... */
 660
 661         start = (pdata->max_freq == 0) ? pdata->bus_freq : pdata->max_freq;
 662         end = pdata->min_freq;
 663
 664         start /= 1000;
 665         end /= 1000;
 666
 667         /* search loop... */
 668
 669         for (; start > end; start--) {
 670                 freq = s3c24xx_i2c_calcdivisor(clkin, start, &div1, &divs);
 671                 if (freq_acceptable(freq, start))
 672                         goto found;
 673         }
 674
 675         /* cannot find frequency spec */
 676
 677         return -EINVAL;
 678
 679  found:
 680         *got = freq;
 681         *iicon |= (divs-1);
 682         *iicon |= (div1 == 512) ? S3C2410_IICCON_TXDIV_512 : 0;
 683         return 0;
 684 }
 685
 686 /* s3c24xx_i2c_init
 687  *
 688  * initialise the controller, set the IO lines and frequency
 689 */
 690
 691 static int s3c24xx_i2c_init(struct s3c24xx_i2c *i2c)
 692 {
 693         unsigned long iicon = S3C2410_IICCON_IRQEN | S3C2410_IICCON_ACKEN;
 694         struct s3c2410_platform_i2c *pdata;
 695         unsigned int freq;
 696
 697         /* get the plafrom data */
 698
 699         pdata = s3c24xx_i2c_get_platformdata(i2c->adap.dev.parent);
 700
 701         /* inititalise the gpio */
 702
 703         s3c2410_gpio_cfgpin(S3C2410_GPE15, S3C2410_GPE15_IICSDA);
 704         s3c2410_gpio_cfgpin(S3C2410_GPE14, S3C2410_GPE14_IICSCL);
 705
 706         /* write slave address */
 707
 708         writeb(pdata->slave_addr, i2c->regs + S3C2410_IICADD);
 709
 710         dev_info(i2c->dev, "slave address 0x%02x\n", pdata->slave_addr);
 711
 712         /* we need to work out the divisors for the clock... */
 713
 714         if (s3c24xx_i2c_getdivisor(i2c, pdata, &iicon, &freq) != 0) {
 715                 dev_err(i2c->dev, "cannot meet bus frequency required\n");
 716                 return -EINVAL;
 717         }
 718
 719         /* todo - check that the i2c lines aren't being dragged anywhere */
 720
 721         dev_info(i2c->dev, "bus frequency set to %d KHz\n", freq);
 722         dev_dbg(i2c->dev, "S3C2410_IICCON=0x%02lx\n", iicon);
 723
 724         writel(iicon, i2c->regs + S3C2410_IICCON);
 725
 726         /* check for s3c2440 i2c controller  */
 727
 728         if (s3c24xx_i2c_is2440(i2c)) {
 729                 dev_dbg(i2c->dev, "S3C2440_IICLC=%08x\n", pdata->sda_delay);
 730
 731                 writel(pdata->sda_delay, i2c->regs + S3C2440_IICLC);
 732         }
 733
 734         return 0;
 735 }
 736
 737 static void s3c24xx_i2c_free(struct s3c24xx_i2c *i2c)
 738 {
 739         if (i2c->clk != NULL && !IS_ERR(i2c->clk)) {
 740                 clk_disable(i2c->clk);
 741                 clk_unuse(i2c->clk);
 742                 clk_put(i2c->clk);
 743                 i2c->clk = NULL;
 744         }
 745
 746         if (i2c->regs != NULL) {
 747                 iounmap(i2c->regs);
 748                 i2c->regs = NULL;
 749         }
 750
 751         if (i2c->ioarea != NULL) {
 752                 release_resource(i2c->ioarea);
 753                 kfree(i2c->ioarea);
 754                 i2c->ioarea = NULL;
 755         }
 756 }
 757
 758 /* s3c24xx_i2c_probe
 759  *
 760  * called by the bus driver when a suitable device is found
 761 */
 762
 763 static int s3c24xx_i2c_probe(struct device *dev)
 764 {
 765         struct platform_device *pdev = to_platform_device(dev);
 766         struct s3c24xx_i2c *i2c = &s3c24xx_i2c;
 767         struct resource *res;
 768         int ret;
 769
 770         /* find the clock and enable it */
 771
 772         i2c->dev = dev;
 773         i2c->clk = clk_get(dev, "i2c");
 774         if (IS_ERR(i2c->clk)) {
 775                 dev_err(dev, "cannot get clock\n");
 776                 ret = -ENOENT;
 777                 goto out;
 778         }
 779
 780         dev_dbg(dev, "clock source %p\n", i2c->clk);
 781
 782         clk_use(i2c->clk);
 783         clk_enable(i2c->clk);
 784
 785         /* map the registers */
 786
 787         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 788         if (res == NULL) {
 789                 dev_err(dev, "cannot find IO resource\n");
 790                 ret = -ENOENT;
 791                 goto out;
 792         }
 793
 794         i2c->ioarea = request_mem_region(res->start, (res->end-res->start)+1,
 795                                          pdev->name);
 796
 797         if (i2c->ioarea == NULL) {
 798                 dev_err(dev, "cannot request IO\n");
 799                 ret = -ENXIO;
 800                 goto out;
 801         }
 802
 803         i2c->regs = ioremap(res->start, (res->end-res->start)+1);
 804
 805         if (i2c->regs == NULL) {
 806                 dev_err(dev, "cannot map IO\n");
 807                 ret = -ENXIO;
 808                 goto out;
 809         }
 810
 811         dev_dbg(dev, "registers %p (%p, %p)\n", i2c->regs, i2c->ioarea, res);
 812
 813         /* setup info block for the i2c core */
 814
 815         i2c->adap.algo_data = i2c;
 816         i2c->adap.dev.parent = dev;
 817
 818         /* initialise the i2c controller */
 819
 820         ret = s3c24xx_i2c_init(i2c);
 821         if (ret != 0)
 822                 goto out;
 823
 824         /* find the IRQ for this unit (note, this relies on the init call to
 825          * ensure no current IRQs pending
 826          */
 827
 828         res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
 829         if (res == NULL) {
 830                 dev_err(dev, "cannot find IRQ\n");
 831                 ret = -ENOENT;
 832                 goto out;
 833         }
 834
 835         ret = request_irq(res->start, s3c24xx_i2c_irq, SA_INTERRUPT,
 836                           pdev->name, i2c);
 837
 838         if (ret != 0) {
 839                 dev_err(dev, "cannot claim IRQ\n");
 840                 goto out;
 841         }
 842
 843         i2c->irq = res;
 844
 845         dev_dbg(dev, "irq resource %p (%ld)\n", res, res->start);
 846
 847         ret = i2c_add_adapter(&i2c->adap);
 848         if (ret < 0) {
 849                 dev_err(dev, "failed to add bus to i2c core\n");
 850                 goto out;
 851         }
 852
 853         dev_set_drvdata(dev, i2c);
 854
 855         dev_info(dev, "%s: S3C I2C adapter\n", i2c->adap.dev.bus_id);
 856
 857  out:
 858         if (ret < 0)
 859                 s3c24xx_i2c_free(i2c);
 860
 861         return ret;
 862 }
 863
 864 /* s3c24xx_i2c_remove
 865  *
 866  * called when device is removed from the bus
 867 */
 868
 869 static int s3c24xx_i2c_remove(struct device *dev)
 870 {
 871         struct s3c24xx_i2c *i2c = dev_get_drvdata(dev);
 872
 873         if (i2c != NULL) {
 874                 s3c24xx_i2c_free(i2c);
 875                 dev_set_drvdata(dev, NULL);
 876         }
 877
 878         return 0;
 879 }
 880
 881 #ifdef CONFIG_PM
 882 static int s3c24xx_i2c_resume(struct device *dev)
 883 {
 884         struct s3c24xx_i2c *i2c = dev_get_drvdata(dev);
 885
 886         if (i2c != NULL)
 887                 s3c24xx_i2c_init(i2c);
 888
 889         return 0;
 890 }
 891
 892 #else
 893 #define s3c24xx_i2c_resume NULL
 894 #endif
 895
 896 /* device driver for platform bus bits */
 897
 898 static struct device_driver s3c2410_i2c_driver = {
 899         .owner          = THIS_MODULE,
 900         .name           = "s3c2410-i2c",
 901         .bus            = &platform_bus_type,
 902         .probe          = s3c24xx_i2c_probe,
 903         .remove         = s3c24xx_i2c_remove,
 904         .resume         = s3c24xx_i2c_resume,
 905 };
 906
 907 static struct device_driver s3c2440_i2c_driver = {
 908         .owner          = THIS_MODULE,
 909         .name           = "s3c2440-i2c",
 910         .bus            = &platform_bus_type,
 911         .probe          = s3c24xx_i2c_probe,
 912         .remove         = s3c24xx_i2c_remove,
 913         .resume         = s3c24xx_i2c_resume,
 914 };
 915
 916 static int __init i2c_adap_s3c_init(void)
 917 {
 918         int ret;
 919
 920         ret = driver_register(&s3c2410_i2c_driver);
 921         if (ret == 0)
 922                 ret = driver_register(&s3c2440_i2c_driver);
 923
 924         return ret;
 925 }
 926
 927 static void __exit i2c_adap_s3c_exit(void)
 928 {
 929         driver_unregister(&s3c2410_i2c_driver);
 930         driver_unregister(&s3c2440_i2c_driver);
 931 }
 932
 933 module_init(i2c_adap_s3c_init);
 934 module_exit(i2c_adap_s3c_exit);
 935
 936 MODULE_DESCRIPTION("S3C24XX I2C Bus driver");
 937 MODULE_AUTHOR("Ben Dooks, <ben@simtec.co.uk>");
 938 MODULE_LICENSE("GPL");