git.oblomov.eu Git - linux-2.6/blob - 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/kernel.h>
  24 #include <linux/module.h>
  25
  26 #include <linux/i2c.h>
  27 #include <linux/i2c-id.h>
  28 #include <linux/init.h>
  29 #include <linux/time.h>
  30 #include <linux/interrupt.h>
  31 #include <linux/delay.h>
  32 #include <linux/errno.h>
  33 #include <linux/err.h>
  34 #include <linux/platform_device.h>
  35 #include <linux/clk.h>
  36
  37 #include <asm/hardware.h>
  38 #include <asm/irq.h>
  39 #include <asm/io.h>
  40
  41 #include <asm/arch/regs-gpio.h>
  42 #include <asm/arch/regs-iic.h>
  43 #include <asm/arch/iic.h>
  44
  45 /* i2c controller state */
  46
  47 enum s3c24xx_i2c_state {
  48         STATE_IDLE,
  49         STATE_START,
  50         STATE_READ,
  51         STATE_WRITE,
  52         STATE_STOP
  53 };
  54
  55 struct s3c24xx_i2c {
  56         spinlock_t              lock;
  57         wait_queue_head_t       wait;
  58
  59         struct i2c_msg          *msg;
  60         unsigned int            msg_num;
  61         unsigned int            msg_idx;
  62         unsigned int            msg_ptr;
  63
  64         enum s3c24xx_i2c_state  state;
  65
  66         void __iomem            *regs;
  67         struct clk              *clk;
  68         struct device           *dev;
  69         struct resource         *irq;
  70         struct resource         *ioarea;
  71         struct i2c_adapter      adap;
  72 };
  73
  74 /* default platform data to use if not supplied in the platform_device
  75 */
  76
  77 static struct s3c2410_platform_i2c s3c24xx_i2c_default_platform = {
  78         .flags          = 0,
  79         .slave_addr     = 0x10,
  80         .bus_freq       = 100*1000,
  81         .max_freq       = 400*1000,
  82         .sda_delay      = S3C2410_IICLC_SDA_DELAY5 | S3C2410_IICLC_FILTER_ON,
  83 };
  84
  85 /* s3c24xx_i2c_is2440()
  86  *
  87  * return true is this is an s3c2440
  88 */
  89
  90 static inline int s3c24xx_i2c_is2440(struct s3c24xx_i2c *i2c)
  91 {
  92         struct platform_device *pdev = to_platform_device(i2c->dev);
  93
  94         return !strcmp(pdev->name, "s3c2440-i2c");
  95 }
  96
  97
  98 /* s3c24xx_i2c_get_platformdata
  99  *
 100  * get the platform data associated with the given device, or return
 101  * the default if there is none
 102 */
 103
 104 static inline struct s3c2410_platform_i2c *s3c24xx_i2c_get_platformdata(struct device *dev)
 105 {
 106         if (dev->platform_data != NULL)
 107                 return (struct s3c2410_platform_i2c *)dev->platform_data;
 108
 109         return &s3c24xx_i2c_default_platform;
 110 }
 111
 112 /* s3c24xx_i2c_master_complete
 113  *
 114  * complete the message and wake up the caller, using the given return code,
 115  * or zero to mean ok.
 116 */
 117
 118 static inline void s3c24xx_i2c_master_complete(struct s3c24xx_i2c *i2c, int ret)
 119 {
 120         dev_dbg(i2c->dev, "master_complete %d\n", ret);
 121
 122         i2c->msg_ptr = 0;
 123         i2c->msg = NULL;
 124         i2c->msg_idx ++;
 125         i2c->msg_num = 0;
 126         if (ret)
 127                 i2c->msg_idx = ret;
 128
 129         wake_up(&i2c->wait);
 130 }
 131
 132 static inline void s3c24xx_i2c_disable_ack(struct s3c24xx_i2c *i2c)
 133 {
 134         unsigned long tmp;
 135
 136         tmp = readl(i2c->regs + S3C2410_IICCON);
 137         writel(tmp & ~S3C2410_IICCON_ACKEN, i2c->regs + S3C2410_IICCON);
 138
 139 }
 140
 141 static inline void s3c24xx_i2c_enable_ack(struct s3c24xx_i2c *i2c)
 142 {
 143         unsigned long tmp;
 144
 145         tmp = readl(i2c->regs + S3C2410_IICCON);
 146         writel(tmp | S3C2410_IICCON_ACKEN, i2c->regs + S3C2410_IICCON);
 147
 148 }
 149
 150 /* irq enable/disable functions */
 151
 152 static inline void s3c24xx_i2c_disable_irq(struct s3c24xx_i2c *i2c)
 153 {
 154         unsigned long tmp;
 155
 156         tmp = readl(i2c->regs + S3C2410_IICCON);
 157         writel(tmp & ~S3C2410_IICCON_IRQEN, i2c->regs + S3C2410_IICCON);
 158 }
 159
 160 static inline void s3c24xx_i2c_enable_irq(struct s3c24xx_i2c *i2c)
 161 {
 162         unsigned long tmp;
 163
 164         tmp = readl(i2c->regs + S3C2410_IICCON);
 165         writel(tmp | S3C2410_IICCON_IRQEN, i2c->regs + S3C2410_IICCON);
 166 }
 167
 168
 169 /* s3c24xx_i2c_message_start
 170  *
 171  * put the start of a message onto the bus
 172 */
 173
 174 static void s3c24xx_i2c_message_start(struct s3c24xx_i2c *i2c,
 175                                       struct i2c_msg *msg)
 176 {
 177         unsigned int addr = (msg->addr & 0x7f) << 1;
 178         unsigned long stat;
 179         unsigned long iiccon;
 180
 181         stat = 0;
 182         stat |=  S3C2410_IICSTAT_TXRXEN;
 183
 184         if (msg->flags & I2C_M_RD) {
 185                 stat |= S3C2410_IICSTAT_MASTER_RX;
 186                 addr |= 1;
 187         } else
 188                 stat |= S3C2410_IICSTAT_MASTER_TX;
 189
 190         if (msg->flags & I2C_M_REV_DIR_ADDR)
 191                 addr ^= 1;
 192
 193         // todo - check for wether ack wanted or not
 194         s3c24xx_i2c_enable_ack(i2c);
 195
 196         iiccon = readl(i2c->regs + S3C2410_IICCON);
 197         writel(stat, i2c->regs + S3C2410_IICSTAT);
 198
 199         dev_dbg(i2c->dev, "START: %08lx to IICSTAT, %02x to DS\n", stat, addr);
 200         writeb(addr, i2c->regs + S3C2410_IICDS);
 201
 202         // delay a bit and reset iiccon before setting start (per samsung)
 203         udelay(1);
 204         dev_dbg(i2c->dev, "iiccon, %08lx\n", iiccon);
 205         writel(iiccon, i2c->regs + S3C2410_IICCON);
 206
 207         stat |=  S3C2410_IICSTAT_START;
 208         writel(stat, i2c->regs + S3C2410_IICSTAT);
 209 }
 210
 211 static inline void s3c24xx_i2c_stop(struct s3c24xx_i2c *i2c, int ret)
 212 {
 213         unsigned long iicstat = readl(i2c->regs + S3C2410_IICSTAT);
 214
 215         dev_dbg(i2c->dev, "STOP\n");
 216
 217         /* stop the transfer */
 218         iicstat &= ~ S3C2410_IICSTAT_START;
 219         writel(iicstat, i2c->regs + S3C2410_IICSTAT);
 220
 221         i2c->state = STATE_STOP;
 222
 223         s3c24xx_i2c_master_complete(i2c, ret);
 224         s3c24xx_i2c_disable_irq(i2c);
 225 }
 226
 227 /* helper functions to determine the current state in the set of
 228  * messages we are sending */
 229
 230 /* is_lastmsg()
 231  *
 232  * returns TRUE if the current message is the last in the set
 233 */
 234
 235 static inline int is_lastmsg(struct s3c24xx_i2c *i2c)
 236 {
 237         return i2c->msg_idx >= (i2c->msg_num - 1);
 238 }
 239
 240 /* is_msglast
 241  *
 242  * returns TRUE if we this is the last byte in the current message
 243 */
 244
 245 static inline int is_msglast(struct s3c24xx_i2c *i2c)
 246 {
 247         return i2c->msg_ptr == i2c->msg->len-1;
 248 }
 249
 250 /* is_msgend
 251  *
 252  * returns TRUE if we reached the end of the current message
 253 */
 254
 255 static inline int is_msgend(struct s3c24xx_i2c *i2c)
 256 {
 257         return i2c->msg_ptr >= i2c->msg->len;
 258 }
 259
 260 /* i2s_s3c_irq_nextbyte
 261  *
 262  * process an interrupt and work out what to do
 263  */
 264
 265 static int i2s_s3c_irq_nextbyte(struct s3c24xx_i2c *i2c, unsigned long iicstat)
 266 {
 267         unsigned long tmp;
 268         unsigned char byte;
 269         int ret = 0;
 270
 271         switch (i2c->state) {
 272
 273         case STATE_IDLE:
 274                 dev_err(i2c->dev, "%s: called in STATE_IDLE\n", __FUNCTION__);
 275                 goto out;
 276                 break;
 277
 278         case STATE_STOP:
 279                 dev_err(i2c->dev, "%s: called in STATE_STOP\n", __FUNCTION__);
 280                 s3c24xx_i2c_disable_irq(i2c);
 281                 goto out_ack;
 282
 283         case STATE_START:
 284                 /* last thing we did was send a start condition on the
 285                  * bus, or started a new i2c message
 286                  */
 287
 288                 if (iicstat  & S3C2410_IICSTAT_LASTBIT &&
 289                     !(i2c->msg->flags & I2C_M_IGNORE_NAK)) {
 290                         /* ack was not received... */
 291
 292                         dev_dbg(i2c->dev, "ack was not received\n");
 293                         s3c24xx_i2c_stop(i2c, -EREMOTEIO);
 294                         goto out_ack;
 295                 }
 296
 297                 if (i2c->msg->flags & I2C_M_RD)
 298                         i2c->state = STATE_READ;
 299                 else
 300                         i2c->state = STATE_WRITE;
 301
 302                 /* terminate the transfer if there is nothing to do
 303                  * (used by the i2c probe to find devices */
 304
 305                 if (is_lastmsg(i2c) && i2c->msg->len == 0) {
 306                         s3c24xx_i2c_stop(i2c, 0);
 307                         goto out_ack;
 308                 }
 309
 310                 if (i2c->state == STATE_READ)
 311                         goto prepare_read;
 312
 313                 /* fall through to the write state, as we will need to
 314                  * send a byte as well */
 315
 316         case STATE_WRITE:
 317                 /* we are writing data to the device... check for the
 318                  * end of the message, and if so, work out what to do
 319                  */
 320
 321         retry_write:
 322                 if (!is_msgend(i2c)) {
 323                         byte = i2c->msg->buf[i2c->msg_ptr++];
 324                         writeb(byte, i2c->regs + S3C2410_IICDS);
 325
 326                 } else if (!is_lastmsg(i2c)) {
 327                         /* we need to go to the next i2c message */
 328
 329                         dev_dbg(i2c->dev, "WRITE: Next Message\n");
 330
 331                         i2c->msg_ptr = 0;
 332                         i2c->msg_idx ++;
 333                         i2c->msg++;
 334
 335                         /* check to see if we need to do another message */
 336                         if (i2c->msg->flags & I2C_M_NOSTART) {
 337
 338                                 if (i2c->msg->flags & I2C_M_RD) {
 339                                         /* cannot do this, the controller
 340                                          * forces us to send a new START
 341                                          * when we change direction */
 342
 343                                         s3c24xx_i2c_stop(i2c, -EINVAL);
 344                                 }
 345
 346                                 goto retry_write;
 347                         } else {
 348
 349                                 /* send the new start */
 350                                 s3c24xx_i2c_message_start(i2c, i2c->msg);
 351                                 i2c->state = STATE_START;
 352                         }
 353
 354                 } else {
 355                         /* send stop */
 356
 357                         s3c24xx_i2c_stop(i2c, 0);
 358                 }
 359                 break;
 360
 361         case STATE_READ:
 362                 /* we have a byte of data in the data register, do
 363                  * something with it, and then work out wether we are
 364                  * going to do any more read/write
 365                  */
 366
 367                 if (!(i2c->msg->flags & I2C_M_IGNORE_NAK) &&
 368                     !(is_msglast(i2c) && is_lastmsg(i2c))) {
 369
 370                         if (iicstat & S3C2410_IICSTAT_LASTBIT) {
 371                                 dev_dbg(i2c->dev, "READ: No Ack\n");
 372
 373                                 s3c24xx_i2c_stop(i2c, -ECONNREFUSED);
 374                                 goto out_ack;
 375                         }
 376                 }
 377
 378                 byte = readb(i2c->regs + S3C2410_IICDS);
 379                 i2c->msg->buf[i2c->msg_ptr++] = byte;
 380
 381         prepare_read:
 382                 if (is_msglast(i2c)) {
 383                         /* last byte of buffer */
 384
 385                         if (is_lastmsg(i2c))
 386                                 s3c24xx_i2c_disable_ack(i2c);
 387
 388                 } else if (is_msgend(i2c)) {
 389                         /* ok, we've read the entire buffer, see if there
 390                          * is anything else we need to do */
 391
 392                         if (is_lastmsg(i2c)) {
 393                                 /* last message, send stop and complete */
 394                                 dev_dbg(i2c->dev, "READ: Send Stop\n");
 395
 396                                 s3c24xx_i2c_stop(i2c, 0);
 397                         } else {
 398                                 /* go to the next transfer */
 399                                 dev_dbg(i2c->dev, "READ: Next Transfer\n");
 400
 401                                 i2c->msg_ptr = 0;
 402                                 i2c->msg_idx++;
 403                                 i2c->msg++;
 404                         }
 405                 }
 406
 407                 break;
 408         }
 409
 410         /* acknowlegde the IRQ and get back on with the work */
 411
 412  out_ack:
 413         tmp = readl(i2c->regs + S3C2410_IICCON);
 414         tmp &= ~S3C2410_IICCON_IRQPEND;
 415         writel(tmp, i2c->regs + S3C2410_IICCON);
 416  out:
 417         return ret;
 418 }
 419
 420 /* s3c24xx_i2c_irq
 421  *
 422  * top level IRQ servicing routine
 423 */
 424
 425 static irqreturn_t s3c24xx_i2c_irq(int irqno, void *dev_id)
 426 {
 427         struct s3c24xx_i2c *i2c = dev_id;
 428         unsigned long status;
 429         unsigned long tmp;
 430
 431         status = readl(i2c->regs + S3C2410_IICSTAT);
 432
 433         if (status & S3C2410_IICSTAT_ARBITR) {
 434                 // deal with arbitration loss
 435                 dev_err(i2c->dev, "deal with arbitration loss\n");
 436         }
 437
 438         if (i2c->state == STATE_IDLE) {
 439                 dev_dbg(i2c->dev, "IRQ: error i2c->state == IDLE\n");
 440
 441                 tmp = readl(i2c->regs + S3C2410_IICCON);
 442                 tmp &= ~S3C2410_IICCON_IRQPEND;
 443                 writel(tmp, i2c->regs +  S3C2410_IICCON);
 444                 goto out;
 445         }
 446
 447         /* pretty much this leaves us with the fact that we've
 448          * transmitted or received whatever byte we last sent */
 449
 450         i2s_s3c_irq_nextbyte(i2c, status);
 451
 452  out:
 453         return IRQ_HANDLED;
 454 }
 455
 456
 457 /* s3c24xx_i2c_set_master
 458  *
 459  * get the i2c bus for a master transaction
 460 */
 461
 462 static int s3c24xx_i2c_set_master(struct s3c24xx_i2c *i2c)
 463 {
 464         unsigned long iicstat;
 465         int timeout = 400;
 466
 467         while (timeout-- > 0) {
 468                 iicstat = readl(i2c->regs + S3C2410_IICSTAT);
 469
 470                 if (!(iicstat & S3C2410_IICSTAT_BUSBUSY))
 471                         return 0;
 472
 473                 msleep(1);
 474         }
 475
 476         dev_dbg(i2c->dev, "timeout: GPEDAT is %08x\n",
 477                 __raw_readl(S3C2410_GPEDAT));
 478
 479         return -ETIMEDOUT;
 480 }
 481
 482 /* s3c24xx_i2c_doxfer
 483  *
 484  * this starts an i2c transfer
 485 */
 486
 487 static int s3c24xx_i2c_doxfer(struct s3c24xx_i2c *i2c, struct i2c_msg *msgs, int num)
 488 {
 489         unsigned long timeout;
 490         int ret;
 491
 492         ret = s3c24xx_i2c_set_master(i2c);
 493         if (ret != 0) {
 494                 dev_err(i2c->dev, "cannot get bus (error %d)\n", ret);
 495                 ret = -EAGAIN;
 496                 goto out;
 497         }
 498
 499         spin_lock_irq(&i2c->lock);
 500
 501         i2c->msg     = msgs;
 502         i2c->msg_num = num;
 503         i2c->msg_ptr = 0;
 504         i2c->msg_idx = 0;
 505         i2c->state   = STATE_START;
 506
 507         s3c24xx_i2c_enable_irq(i2c);
 508         s3c24xx_i2c_message_start(i2c, msgs);
 509         spin_unlock_irq(&i2c->lock);
 510
 511         timeout = wait_event_timeout(i2c->wait, i2c->msg_num == 0, HZ * 5);
 512
 513         ret = i2c->msg_idx;
 514
 515         /* having these next two as dev_err() makes life very
 516          * noisy when doing an i2cdetect */
 517
 518         if (timeout == 0)
 519                 dev_dbg(i2c->dev, "timeout\n");
 520         else if (ret != num)
 521                 dev_dbg(i2c->dev, "incomplete xfer (%d)\n", ret);
 522
 523         /* ensure the stop has been through the bus */
 524
 525         msleep(1);
 526
 527  out:
 528         return ret;
 529 }
 530
 531 /* s3c24xx_i2c_xfer
 532  *
 533  * first port of call from the i2c bus code when an message needs
 534  * transferring across the i2c bus.
 535 */
 536
 537 static int s3c24xx_i2c_xfer(struct i2c_adapter *adap,
 538                         struct i2c_msg *msgs, int num)
 539 {
 540         struct s3c24xx_i2c *i2c = (struct s3c24xx_i2c *)adap->algo_data;
 541         int retry;
 542         int ret;
 543
 544         for (retry = 0; retry < adap->retries; retry++) {
 545
 546                 ret = s3c24xx_i2c_doxfer(i2c, msgs, num);
 547
 548                 if (ret != -EAGAIN)
 549                         return ret;
 550
 551                 dev_dbg(i2c->dev, "Retrying transmission (%d)\n", retry);
 552
 553                 udelay(100);
 554         }
 555
 556         return -EREMOTEIO;
 557 }
 558
 559 /* declare our i2c functionality */
 560 static u32 s3c24xx_i2c_func(struct i2c_adapter *adap)
 561 {
 562         return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_PROTOCOL_MANGLING;
 563 }
 564
 565 /* i2c bus registration info */
 566
 567 static const struct i2c_algorithm s3c24xx_i2c_algorithm = {
 568         .master_xfer            = s3c24xx_i2c_xfer,
 569         .functionality          = s3c24xx_i2c_func,
 570 };
 571
 572 static struct s3c24xx_i2c s3c24xx_i2c = {
 573         .lock   = SPIN_LOCK_UNLOCKED,
 574         .wait   = __WAIT_QUEUE_HEAD_INITIALIZER(s3c24xx_i2c.wait),
 575         .adap   = {
 576                 .name                   = "s3c2410-i2c",
 577                 .owner                  = THIS_MODULE,
 578                 .algo                   = &s3c24xx_i2c_algorithm,
 579                 .retries                = 2,
 580                 .class                  = I2C_CLASS_HWMON,
 581         },
 582 };
 583
 584 /* s3c24xx_i2c_calcdivisor
 585  *
 586  * return the divisor settings for a given frequency
 587 */
 588
 589 static int s3c24xx_i2c_calcdivisor(unsigned long clkin, unsigned int wanted,
 590                                    unsigned int *div1, unsigned int *divs)
 591 {
 592         unsigned int calc_divs = clkin / wanted;
 593         unsigned int calc_div1;
 594
 595         if (calc_divs > (16*16))
 596                 calc_div1 = 512;
 597         else
 598                 calc_div1 = 16;
 599
 600         calc_divs += calc_div1-1;
 601         calc_divs /= calc_div1;
 602
 603         if (calc_divs == 0)
 604                 calc_divs = 1;
 605         if (calc_divs > 17)
 606                 calc_divs = 17;
 607
 608         *divs = calc_divs;
 609         *div1 = calc_div1;
 610
 611         return clkin / (calc_divs * calc_div1);
 612 }
 613
 614 /* freq_acceptable
 615  *
 616  * test wether a frequency is within the acceptable range of error
 617 */
 618
 619 static inline int freq_acceptable(unsigned int freq, unsigned int wanted)
 620 {
 621         int diff = freq - wanted;
 622
 623         return (diff >= -2 && diff <= 2);
 624 }
 625
 626 /* s3c24xx_i2c_getdivisor
 627  *
 628  * work out a divisor for the user requested frequency setting,
 629  * either by the requested frequency, or scanning the acceptable
 630  * range of frequencies until something is found
 631 */
 632
 633 static int s3c24xx_i2c_getdivisor(struct s3c24xx_i2c *i2c,
 634                                   struct s3c2410_platform_i2c *pdata,
 635                                   unsigned long *iicon,
 636                                   unsigned int *got)
 637 {
 638         unsigned long clkin = clk_get_rate(i2c->clk);
 639
 640         unsigned int divs, div1;
 641         int freq;
 642         int start, end;
 643
 644         clkin /= 1000;          /* clkin now in KHz */
 645
 646         dev_dbg(i2c->dev,  "pdata %p, freq %lu %lu..%lu\n",
 647                  pdata, pdata->bus_freq, pdata->min_freq, pdata->max_freq);
 648
 649         if (pdata->bus_freq != 0) {
 650                 freq = s3c24xx_i2c_calcdivisor(clkin, pdata->bus_freq/1000,
 651                                                &div1, &divs);
 652                 if (freq_acceptable(freq, pdata->bus_freq/1000))
 653                         goto found;
 654         }
 655
 656         /* ok, we may have to search for something suitable... */
 657
 658         start = (pdata->max_freq == 0) ? pdata->bus_freq : pdata->max_freq;
 659         end = pdata->min_freq;
 660
 661         start /= 1000;
 662         end /= 1000;
 663
 664         /* search loop... */
 665
 666         for (; start > end; start--) {
 667                 freq = s3c24xx_i2c_calcdivisor(clkin, start, &div1, &divs);
 668                 if (freq_acceptable(freq, start))
 669                         goto found;
 670         }
 671
 672         /* cannot find frequency spec */
 673
 674         return -EINVAL;
 675
 676  found:
 677         *got = freq;
 678         *iicon |= (divs-1);
 679         *iicon |= (div1 == 512) ? S3C2410_IICCON_TXDIV_512 : 0;
 680         return 0;
 681 }
 682
 683 /* s3c24xx_i2c_init
 684  *
 685  * initialise the controller, set the IO lines and frequency
 686 */
 687
 688 static int s3c24xx_i2c_init(struct s3c24xx_i2c *i2c)
 689 {
 690         unsigned long iicon = S3C2410_IICCON_IRQEN | S3C2410_IICCON_ACKEN;
 691         struct s3c2410_platform_i2c *pdata;
 692         unsigned int freq;
 693
 694         /* get the plafrom data */
 695
 696         pdata = s3c24xx_i2c_get_platformdata(i2c->adap.dev.parent);
 697
 698         /* inititalise the gpio */
 699
 700         s3c2410_gpio_cfgpin(S3C2410_GPE15, S3C2410_GPE15_IICSDA);
 701         s3c2410_gpio_cfgpin(S3C2410_GPE14, S3C2410_GPE14_IICSCL);
 702
 703         /* write slave address */
 704
 705         writeb(pdata->slave_addr, i2c->regs + S3C2410_IICADD);
 706
 707         dev_info(i2c->dev, "slave address 0x%02x\n", pdata->slave_addr);
 708
 709         /* we need to work out the divisors for the clock... */
 710
 711         if (s3c24xx_i2c_getdivisor(i2c, pdata, &iicon, &freq) != 0) {
 712                 dev_err(i2c->dev, "cannot meet bus frequency required\n");
 713                 return -EINVAL;
 714         }
 715
 716         /* todo - check that the i2c lines aren't being dragged anywhere */
 717
 718         dev_info(i2c->dev, "bus frequency set to %d KHz\n", freq);
 719         dev_dbg(i2c->dev, "S3C2410_IICCON=0x%02lx\n", iicon);
 720
 721         writel(iicon, i2c->regs + S3C2410_IICCON);
 722
 723         /* check for s3c2440 i2c controller  */
 724
 725         if (s3c24xx_i2c_is2440(i2c)) {
 726                 dev_dbg(i2c->dev, "S3C2440_IICLC=%08x\n", pdata->sda_delay);
 727
 728                 writel(pdata->sda_delay, i2c->regs + S3C2440_IICLC);
 729         }
 730
 731         return 0;
 732 }
 733
 734 static void s3c24xx_i2c_free(struct s3c24xx_i2c *i2c)
 735 {
 736         if (i2c->clk != NULL && !IS_ERR(i2c->clk)) {
 737                 clk_disable(i2c->clk);
 738                 clk_put(i2c->clk);
 739                 i2c->clk = NULL;
 740         }
 741
 742         if (i2c->regs != NULL) {
 743                 iounmap(i2c->regs);
 744                 i2c->regs = NULL;
 745         }
 746
 747         if (i2c->ioarea != NULL) {
 748                 release_resource(i2c->ioarea);
 749                 kfree(i2c->ioarea);
 750                 i2c->ioarea = NULL;
 751         }
 752 }
 753
 754 /* s3c24xx_i2c_probe
 755  *
 756  * called by the bus driver when a suitable device is found
 757 */
 758
 759 static int s3c24xx_i2c_probe(struct platform_device *pdev)
 760 {
 761         struct s3c24xx_i2c *i2c = &s3c24xx_i2c;
 762         struct resource *res;
 763         int ret;
 764
 765         /* find the clock and enable it */
 766
 767         i2c->dev = &pdev->dev;
 768         i2c->clk = clk_get(&pdev->dev, "i2c");
 769         if (IS_ERR(i2c->clk)) {
 770                 dev_err(&pdev->dev, "cannot get clock\n");
 771                 ret = -ENOENT;
 772                 goto out;
 773         }
 774
 775         dev_dbg(&pdev->dev, "clock source %p\n", i2c->clk);
 776
 777         clk_enable(i2c->clk);
 778
 779         /* map the registers */
 780
 781         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 782         if (res == NULL) {
 783                 dev_err(&pdev->dev, "cannot find IO resource\n");
 784                 ret = -ENOENT;
 785                 goto out;
 786         }
 787
 788         i2c->ioarea = request_mem_region(res->start, (res->end-res->start)+1,
 789                                          pdev->name);
 790
 791         if (i2c->ioarea == NULL) {
 792                 dev_err(&pdev->dev, "cannot request IO\n");
 793                 ret = -ENXIO;
 794                 goto out;
 795         }
 796
 797         i2c->regs = ioremap(res->start, (res->end-res->start)+1);
 798
 799         if (i2c->regs == NULL) {
 800                 dev_err(&pdev->dev, "cannot map IO\n");
 801                 ret = -ENXIO;
 802                 goto out;
 803         }
 804
 805         dev_dbg(&pdev->dev, "registers %p (%p, %p)\n", i2c->regs, i2c->ioarea, res);
 806
 807         /* setup info block for the i2c core */
 808
 809         i2c->adap.algo_data = i2c;
 810         i2c->adap.dev.parent = &pdev->dev;
 811
 812         /* initialise the i2c controller */
 813
 814         ret = s3c24xx_i2c_init(i2c);
 815         if (ret != 0)
 816                 goto out;
 817
 818         /* find the IRQ for this unit (note, this relies on the init call to
 819          * ensure no current IRQs pending
 820          */
 821
 822         res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
 823         if (res == NULL) {
 824                 dev_err(&pdev->dev, "cannot find IRQ\n");
 825                 ret = -ENOENT;
 826                 goto out;
 827         }
 828
 829         ret = request_irq(res->start, s3c24xx_i2c_irq, IRQF_DISABLED,
 830                           pdev->name, i2c);
 831
 832         if (ret != 0) {
 833                 dev_err(&pdev->dev, "cannot claim IRQ\n");
 834                 goto out;
 835         }
 836
 837         i2c->irq = res;
 838
 839         dev_dbg(&pdev->dev, "irq resource %p (%ld)\n", res, res->start);
 840
 841         ret = i2c_add_adapter(&i2c->adap);
 842         if (ret < 0) {
 843                 dev_err(&pdev->dev, "failed to add bus to i2c core\n");
 844                 goto out;
 845         }
 846
 847         platform_set_drvdata(pdev, i2c);
 848
 849         dev_info(&pdev->dev, "%s: S3C I2C adapter\n", i2c->adap.dev.bus_id);
 850
 851  out:
 852         if (ret < 0)
 853                 s3c24xx_i2c_free(i2c);
 854
 855         return ret;
 856 }
 857
 858 /* s3c24xx_i2c_remove
 859  *
 860  * called when device is removed from the bus
 861 */
 862
 863 static int s3c24xx_i2c_remove(struct platform_device *pdev)
 864 {
 865         struct s3c24xx_i2c *i2c = platform_get_drvdata(pdev);
 866
 867         if (i2c != NULL) {
 868                 s3c24xx_i2c_free(i2c);
 869                 platform_set_drvdata(pdev, NULL);
 870         }
 871
 872         return 0;
 873 }
 874
 875 #ifdef CONFIG_PM
 876 static int s3c24xx_i2c_resume(struct platform_device *dev)
 877 {
 878         struct s3c24xx_i2c *i2c = platform_get_drvdata(dev);
 879
 880         if (i2c != NULL)
 881                 s3c24xx_i2c_init(i2c);
 882
 883         return 0;
 884 }
 885
 886 #else
 887 #define s3c24xx_i2c_resume NULL
 888 #endif
 889
 890 /* device driver for platform bus bits */
 891
 892 static struct platform_driver s3c2410_i2c_driver = {
 893         .probe          = s3c24xx_i2c_probe,
 894         .remove         = s3c24xx_i2c_remove,
 895         .resume         = s3c24xx_i2c_resume,
 896         .driver         = {
 897                 .owner  = THIS_MODULE,
 898                 .name   = "s3c2410-i2c",
 899         },
 900 };
 901
 902 static struct platform_driver s3c2440_i2c_driver = {
 903         .probe          = s3c24xx_i2c_probe,
 904         .remove         = s3c24xx_i2c_remove,
 905         .resume         = s3c24xx_i2c_resume,
 906         .driver         = {
 907                 .owner  = THIS_MODULE,
 908                 .name   = "s3c2440-i2c",
 909         },
 910 };
 911
 912 static int __init i2c_adap_s3c_init(void)
 913 {
 914         int ret;
 915
 916         ret = platform_driver_register(&s3c2410_i2c_driver);
 917         if (ret == 0) {
 918                 ret = platform_driver_register(&s3c2440_i2c_driver);
 919                 if (ret)
 920                         platform_driver_unregister(&s3c2410_i2c_driver);
 921         }
 922
 923         return ret;
 924 }
 925
 926 static void __exit i2c_adap_s3c_exit(void)
 927 {
 928         platform_driver_unregister(&s3c2410_i2c_driver);
 929         platform_driver_unregister(&s3c2440_i2c_driver);
 930 }
 931
 932 module_init(i2c_adap_s3c_init);
 933 module_exit(i2c_adap_s3c_exit);
 934
 935 MODULE_DESCRIPTION("S3C24XX I2C Bus driver");
 936 MODULE_AUTHOR("Ben Dooks, <ben@simtec.co.uk>");
 937 MODULE_LICENSE("GPL");