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/plat-s3c/regs-iic.h>
  43 #include <asm/plat-s3c/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         unsigned int            tx_setup;
  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 here to ensure the data byte has gotten onto the bus
 205          * before the transaction is started */
 206
 207         ndelay(i2c->tx_setup);
 208
 209         dev_dbg(i2c->dev, "iiccon, %08lx\n", iiccon);
 210         writel(iiccon, i2c->regs + S3C2410_IICCON);
 211
 212         stat |=  S3C2410_IICSTAT_START;
 213         writel(stat, i2c->regs + S3C2410_IICSTAT);
 214 }
 215
 216 static inline void s3c24xx_i2c_stop(struct s3c24xx_i2c *i2c, int ret)
 217 {
 218         unsigned long iicstat = readl(i2c->regs + S3C2410_IICSTAT);
 219
 220         dev_dbg(i2c->dev, "STOP\n");
 221
 222         /* stop the transfer */
 223         iicstat &= ~ S3C2410_IICSTAT_START;
 224         writel(iicstat, i2c->regs + S3C2410_IICSTAT);
 225
 226         i2c->state = STATE_STOP;
 227
 228         s3c24xx_i2c_master_complete(i2c, ret);
 229         s3c24xx_i2c_disable_irq(i2c);
 230 }
 231
 232 /* helper functions to determine the current state in the set of
 233  * messages we are sending */
 234
 235 /* is_lastmsg()
 236  *
 237  * returns TRUE if the current message is the last in the set
 238 */
 239
 240 static inline int is_lastmsg(struct s3c24xx_i2c *i2c)
 241 {
 242         return i2c->msg_idx >= (i2c->msg_num - 1);
 243 }
 244
 245 /* is_msglast
 246  *
 247  * returns TRUE if we this is the last byte in the current message
 248 */
 249
 250 static inline int is_msglast(struct s3c24xx_i2c *i2c)
 251 {
 252         return i2c->msg_ptr == i2c->msg->len-1;
 253 }
 254
 255 /* is_msgend
 256  *
 257  * returns TRUE if we reached the end of the current message
 258 */
 259
 260 static inline int is_msgend(struct s3c24xx_i2c *i2c)
 261 {
 262         return i2c->msg_ptr >= i2c->msg->len;
 263 }
 264
 265 /* i2s_s3c_irq_nextbyte
 266  *
 267  * process an interrupt and work out what to do
 268  */
 269
 270 static int i2s_s3c_irq_nextbyte(struct s3c24xx_i2c *i2c, unsigned long iicstat)
 271 {
 272         unsigned long tmp;
 273         unsigned char byte;
 274         int ret = 0;
 275
 276         switch (i2c->state) {
 277
 278         case STATE_IDLE:
 279                 dev_err(i2c->dev, "%s: called in STATE_IDLE\n", __FUNCTION__);
 280                 goto out;
 281                 break;
 282
 283         case STATE_STOP:
 284                 dev_err(i2c->dev, "%s: called in STATE_STOP\n", __FUNCTION__);
 285                 s3c24xx_i2c_disable_irq(i2c);
 286                 goto out_ack;
 287
 288         case STATE_START:
 289                 /* last thing we did was send a start condition on the
 290                  * bus, or started a new i2c message
 291                  */
 292
 293                 if (iicstat  & S3C2410_IICSTAT_LASTBIT &&
 294                     !(i2c->msg->flags & I2C_M_IGNORE_NAK)) {
 295                         /* ack was not received... */
 296
 297                         dev_dbg(i2c->dev, "ack was not received\n");
 298                         s3c24xx_i2c_stop(i2c, -EREMOTEIO);
 299                         goto out_ack;
 300                 }
 301
 302                 if (i2c->msg->flags & I2C_M_RD)
 303                         i2c->state = STATE_READ;
 304                 else
 305                         i2c->state = STATE_WRITE;
 306
 307                 /* terminate the transfer if there is nothing to do
 308                  * (used by the i2c probe to find devices */
 309
 310                 if (is_lastmsg(i2c) && i2c->msg->len == 0) {
 311                         s3c24xx_i2c_stop(i2c, 0);
 312                         goto out_ack;
 313                 }
 314
 315                 if (i2c->state == STATE_READ)
 316                         goto prepare_read;
 317
 318                 /* fall through to the write state, as we will need to
 319                  * send a byte as well */
 320
 321         case STATE_WRITE:
 322                 /* we are writing data to the device... check for the
 323                  * end of the message, and if so, work out what to do
 324                  */
 325
 326         retry_write:
 327                 if (!is_msgend(i2c)) {
 328                         byte = i2c->msg->buf[i2c->msg_ptr++];
 329                         writeb(byte, i2c->regs + S3C2410_IICDS);
 330
 331                         /* delay after writing the byte to allow the
 332                          * data setup time on the bus, as writing the
 333                          * data to the register causes the first bit
 334                          * to appear on SDA, and SCL will change as
 335                          * soon as the interrupt is acknowledged */
 336
 337                         ndelay(i2c->tx_setup);
 338
 339                 } else if (!is_lastmsg(i2c)) {
 340                         /* we need to go to the next i2c message */
 341
 342                         dev_dbg(i2c->dev, "WRITE: Next Message\n");
 343
 344                         i2c->msg_ptr = 0;
 345                         i2c->msg_idx ++;
 346                         i2c->msg++;
 347
 348                         /* check to see if we need to do another message */
 349                         if (i2c->msg->flags & I2C_M_NOSTART) {
 350
 351                                 if (i2c->msg->flags & I2C_M_RD) {
 352                                         /* cannot do this, the controller
 353                                          * forces us to send a new START
 354                                          * when we change direction */
 355
 356                                         s3c24xx_i2c_stop(i2c, -EINVAL);
 357                                 }
 358
 359                                 goto retry_write;
 360                         } else {
 361
 362                                 /* send the new start */
 363                                 s3c24xx_i2c_message_start(i2c, i2c->msg);
 364                                 i2c->state = STATE_START;
 365                         }
 366
 367                 } else {
 368                         /* send stop */
 369
 370                         s3c24xx_i2c_stop(i2c, 0);
 371                 }
 372                 break;
 373
 374         case STATE_READ:
 375                 /* we have a byte of data in the data register, do
 376                  * something with it, and then work out wether we are
 377                  * going to do any more read/write
 378                  */
 379
 380                 if (!(i2c->msg->flags & I2C_M_IGNORE_NAK) &&
 381                     !(is_msglast(i2c) && is_lastmsg(i2c))) {
 382
 383                         if (iicstat & S3C2410_IICSTAT_LASTBIT) {
 384                                 dev_dbg(i2c->dev, "READ: No Ack\n");
 385
 386                                 s3c24xx_i2c_stop(i2c, -ECONNREFUSED);
 387                                 goto out_ack;
 388                         }
 389                 }
 390
 391                 byte = readb(i2c->regs + S3C2410_IICDS);
 392                 i2c->msg->buf[i2c->msg_ptr++] = byte;
 393
 394         prepare_read:
 395                 if (is_msglast(i2c)) {
 396                         /* last byte of buffer */
 397
 398                         if (is_lastmsg(i2c))
 399                                 s3c24xx_i2c_disable_ack(i2c);
 400
 401                 } else if (is_msgend(i2c)) {
 402                         /* ok, we've read the entire buffer, see if there
 403                          * is anything else we need to do */
 404
 405                         if (is_lastmsg(i2c)) {
 406                                 /* last message, send stop and complete */
 407                                 dev_dbg(i2c->dev, "READ: Send Stop\n");
 408
 409                                 s3c24xx_i2c_stop(i2c, 0);
 410                         } else {
 411                                 /* go to the next transfer */
 412                                 dev_dbg(i2c->dev, "READ: Next Transfer\n");
 413
 414                                 i2c->msg_ptr = 0;
 415                                 i2c->msg_idx++;
 416                                 i2c->msg++;
 417                         }
 418                 }
 419
 420                 break;
 421         }
 422
 423         /* acknowlegde the IRQ and get back on with the work */
 424
 425  out_ack:
 426         tmp = readl(i2c->regs + S3C2410_IICCON);
 427         tmp &= ~S3C2410_IICCON_IRQPEND;
 428         writel(tmp, i2c->regs + S3C2410_IICCON);
 429  out:
 430         return ret;
 431 }
 432
 433 /* s3c24xx_i2c_irq
 434  *
 435  * top level IRQ servicing routine
 436 */
 437
 438 static irqreturn_t s3c24xx_i2c_irq(int irqno, void *dev_id)
 439 {
 440         struct s3c24xx_i2c *i2c = dev_id;
 441         unsigned long status;
 442         unsigned long tmp;
 443
 444         status = readl(i2c->regs + S3C2410_IICSTAT);
 445
 446         if (status & S3C2410_IICSTAT_ARBITR) {
 447                 // deal with arbitration loss
 448                 dev_err(i2c->dev, "deal with arbitration loss\n");
 449         }
 450
 451         if (i2c->state == STATE_IDLE) {
 452                 dev_dbg(i2c->dev, "IRQ: error i2c->state == IDLE\n");
 453
 454                 tmp = readl(i2c->regs + S3C2410_IICCON);
 455                 tmp &= ~S3C2410_IICCON_IRQPEND;
 456                 writel(tmp, i2c->regs +  S3C2410_IICCON);
 457                 goto out;
 458         }
 459
 460         /* pretty much this leaves us with the fact that we've
 461          * transmitted or received whatever byte we last sent */
 462
 463         i2s_s3c_irq_nextbyte(i2c, status);
 464
 465  out:
 466         return IRQ_HANDLED;
 467 }
 468
 469
 470 /* s3c24xx_i2c_set_master
 471  *
 472  * get the i2c bus for a master transaction
 473 */
 474
 475 static int s3c24xx_i2c_set_master(struct s3c24xx_i2c *i2c)
 476 {
 477         unsigned long iicstat;
 478         int timeout = 400;
 479
 480         while (timeout-- > 0) {
 481                 iicstat = readl(i2c->regs + S3C2410_IICSTAT);
 482
 483                 if (!(iicstat & S3C2410_IICSTAT_BUSBUSY))
 484                         return 0;
 485
 486                 msleep(1);
 487         }
 488
 489         dev_dbg(i2c->dev, "timeout: GPEDAT is %08x\n",
 490                 __raw_readl(S3C2410_GPEDAT));
 491
 492         return -ETIMEDOUT;
 493 }
 494
 495 /* s3c24xx_i2c_doxfer
 496  *
 497  * this starts an i2c transfer
 498 */
 499
 500 static int s3c24xx_i2c_doxfer(struct s3c24xx_i2c *i2c, struct i2c_msg *msgs, int num)
 501 {
 502         unsigned long timeout;
 503         int ret;
 504
 505         ret = s3c24xx_i2c_set_master(i2c);
 506         if (ret != 0) {
 507                 dev_err(i2c->dev, "cannot get bus (error %d)\n", ret);
 508                 ret = -EAGAIN;
 509                 goto out;
 510         }
 511
 512         spin_lock_irq(&i2c->lock);
 513
 514         i2c->msg     = msgs;
 515         i2c->msg_num = num;
 516         i2c->msg_ptr = 0;
 517         i2c->msg_idx = 0;
 518         i2c->state   = STATE_START;
 519
 520         s3c24xx_i2c_enable_irq(i2c);
 521         s3c24xx_i2c_message_start(i2c, msgs);
 522         spin_unlock_irq(&i2c->lock);
 523
 524         timeout = wait_event_timeout(i2c->wait, i2c->msg_num == 0, HZ * 5);
 525
 526         ret = i2c->msg_idx;
 527
 528         /* having these next two as dev_err() makes life very
 529          * noisy when doing an i2cdetect */
 530
 531         if (timeout == 0)
 532                 dev_dbg(i2c->dev, "timeout\n");
 533         else if (ret != num)
 534                 dev_dbg(i2c->dev, "incomplete xfer (%d)\n", ret);
 535
 536         /* ensure the stop has been through the bus */
 537
 538         msleep(1);
 539
 540  out:
 541         return ret;
 542 }
 543
 544 /* s3c24xx_i2c_xfer
 545  *
 546  * first port of call from the i2c bus code when an message needs
 547  * transferring across the i2c bus.
 548 */
 549
 550 static int s3c24xx_i2c_xfer(struct i2c_adapter *adap,
 551                         struct i2c_msg *msgs, int num)
 552 {
 553         struct s3c24xx_i2c *i2c = (struct s3c24xx_i2c *)adap->algo_data;
 554         int retry;
 555         int ret;
 556
 557         for (retry = 0; retry < adap->retries; retry++) {
 558
 559                 ret = s3c24xx_i2c_doxfer(i2c, msgs, num);
 560
 561                 if (ret != -EAGAIN)
 562                         return ret;
 563
 564                 dev_dbg(i2c->dev, "Retrying transmission (%d)\n", retry);
 565
 566                 udelay(100);
 567         }
 568
 569         return -EREMOTEIO;
 570 }
 571
 572 /* declare our i2c functionality */
 573 static u32 s3c24xx_i2c_func(struct i2c_adapter *adap)
 574 {
 575         return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_PROTOCOL_MANGLING;
 576 }
 577
 578 /* i2c bus registration info */
 579
 580 static const struct i2c_algorithm s3c24xx_i2c_algorithm = {
 581         .master_xfer            = s3c24xx_i2c_xfer,
 582         .functionality          = s3c24xx_i2c_func,
 583 };
 584
 585 static struct s3c24xx_i2c s3c24xx_i2c = {
 586         .lock           = __SPIN_LOCK_UNLOCKED(s3c24xx_i2c.lock),
 587         .wait           = __WAIT_QUEUE_HEAD_INITIALIZER(s3c24xx_i2c.wait),
 588         .tx_setup       = 50,
 589         .adap           = {
 590                 .name                   = "s3c2410-i2c",
 591                 .owner                  = THIS_MODULE,
 592                 .algo                   = &s3c24xx_i2c_algorithm,
 593                 .retries                = 2,
 594                 .class                  = I2C_CLASS_HWMON,
 595         },
 596 };
 597
 598 /* s3c24xx_i2c_calcdivisor
 599  *
 600  * return the divisor settings for a given frequency
 601 */
 602
 603 static int s3c24xx_i2c_calcdivisor(unsigned long clkin, unsigned int wanted,
 604                                    unsigned int *div1, unsigned int *divs)
 605 {
 606         unsigned int calc_divs = clkin / wanted;
 607         unsigned int calc_div1;
 608
 609         if (calc_divs > (16*16))
 610                 calc_div1 = 512;
 611         else
 612                 calc_div1 = 16;
 613
 614         calc_divs += calc_div1-1;
 615         calc_divs /= calc_div1;
 616
 617         if (calc_divs == 0)
 618                 calc_divs = 1;
 619         if (calc_divs > 17)
 620                 calc_divs = 17;
 621
 622         *divs = calc_divs;
 623         *div1 = calc_div1;
 624
 625         return clkin / (calc_divs * calc_div1);
 626 }
 627
 628 /* freq_acceptable
 629  *
 630  * test wether a frequency is within the acceptable range of error
 631 */
 632
 633 static inline int freq_acceptable(unsigned int freq, unsigned int wanted)
 634 {
 635         int diff = freq - wanted;
 636
 637         return (diff >= -2 && diff <= 2);
 638 }
 639
 640 /* s3c24xx_i2c_getdivisor
 641  *
 642  * work out a divisor for the user requested frequency setting,
 643  * either by the requested frequency, or scanning the acceptable
 644  * range of frequencies until something is found
 645 */
 646
 647 static int s3c24xx_i2c_getdivisor(struct s3c24xx_i2c *i2c,
 648                                   struct s3c2410_platform_i2c *pdata,
 649                                   unsigned long *iicon,
 650                                   unsigned int *got)
 651 {
 652         unsigned long clkin = clk_get_rate(i2c->clk);
 653
 654         unsigned int divs, div1;
 655         int freq;
 656         int start, end;
 657
 658         clkin /= 1000;          /* clkin now in KHz */
 659
 660         dev_dbg(i2c->dev,  "pdata %p, freq %lu %lu..%lu\n",
 661                  pdata, pdata->bus_freq, pdata->min_freq, pdata->max_freq);
 662
 663         if (pdata->bus_freq != 0) {
 664                 freq = s3c24xx_i2c_calcdivisor(clkin, pdata->bus_freq/1000,
 665                                                &div1, &divs);
 666                 if (freq_acceptable(freq, pdata->bus_freq/1000))
 667                         goto found;
 668         }
 669
 670         /* ok, we may have to search for something suitable... */
 671
 672         start = (pdata->max_freq == 0) ? pdata->bus_freq : pdata->max_freq;
 673         end = pdata->min_freq;
 674
 675         start /= 1000;
 676         end /= 1000;
 677
 678         /* search loop... */
 679
 680         for (; start > end; start--) {
 681                 freq = s3c24xx_i2c_calcdivisor(clkin, start, &div1, &divs);
 682                 if (freq_acceptable(freq, start))
 683                         goto found;
 684         }
 685
 686         /* cannot find frequency spec */
 687
 688         return -EINVAL;
 689
 690  found:
 691         *got = freq;
 692         *iicon |= (divs-1);
 693         *iicon |= (div1 == 512) ? S3C2410_IICCON_TXDIV_512 : 0;
 694         return 0;
 695 }
 696
 697 /* s3c24xx_i2c_init
 698  *
 699  * initialise the controller, set the IO lines and frequency
 700 */
 701
 702 static int s3c24xx_i2c_init(struct s3c24xx_i2c *i2c)
 703 {
 704         unsigned long iicon = S3C2410_IICCON_IRQEN | S3C2410_IICCON_ACKEN;
 705         struct s3c2410_platform_i2c *pdata;
 706         unsigned int freq;
 707
 708         /* get the plafrom data */
 709
 710         pdata = s3c24xx_i2c_get_platformdata(i2c->adap.dev.parent);
 711
 712         /* inititalise the gpio */
 713
 714         s3c2410_gpio_cfgpin(S3C2410_GPE15, S3C2410_GPE15_IICSDA);
 715         s3c2410_gpio_cfgpin(S3C2410_GPE14, S3C2410_GPE14_IICSCL);
 716
 717         /* write slave address */
 718
 719         writeb(pdata->slave_addr, i2c->regs + S3C2410_IICADD);
 720
 721         dev_info(i2c->dev, "slave address 0x%02x\n", pdata->slave_addr);
 722
 723         /* we need to work out the divisors for the clock... */
 724
 725         if (s3c24xx_i2c_getdivisor(i2c, pdata, &iicon, &freq) != 0) {
 726                 dev_err(i2c->dev, "cannot meet bus frequency required\n");
 727                 return -EINVAL;
 728         }
 729
 730         /* todo - check that the i2c lines aren't being dragged anywhere */
 731
 732         dev_info(i2c->dev, "bus frequency set to %d KHz\n", freq);
 733         dev_dbg(i2c->dev, "S3C2410_IICCON=0x%02lx\n", iicon);
 734
 735         writel(iicon, i2c->regs + S3C2410_IICCON);
 736
 737         /* check for s3c2440 i2c controller  */
 738
 739         if (s3c24xx_i2c_is2440(i2c)) {
 740                 dev_dbg(i2c->dev, "S3C2440_IICLC=%08x\n", pdata->sda_delay);
 741
 742                 writel(pdata->sda_delay, i2c->regs + S3C2440_IICLC);
 743         }
 744
 745         return 0;
 746 }
 747
 748 /* s3c24xx_i2c_probe
 749  *
 750  * called by the bus driver when a suitable device is found
 751 */
 752
 753 static int s3c24xx_i2c_probe(struct platform_device *pdev)
 754 {
 755         struct s3c24xx_i2c *i2c = &s3c24xx_i2c;
 756         struct resource *res;
 757         int ret;
 758
 759         /* find the clock and enable it */
 760
 761         i2c->dev = &pdev->dev;
 762         i2c->clk = clk_get(&pdev->dev, "i2c");
 763         if (IS_ERR(i2c->clk)) {
 764                 dev_err(&pdev->dev, "cannot get clock\n");
 765                 ret = -ENOENT;
 766                 goto err_noclk;
 767         }
 768
 769         dev_dbg(&pdev->dev, "clock source %p\n", i2c->clk);
 770
 771         clk_enable(i2c->clk);
 772
 773         /* map the registers */
 774
 775         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 776         if (res == NULL) {
 777                 dev_err(&pdev->dev, "cannot find IO resource\n");
 778                 ret = -ENOENT;
 779                 goto err_clk;
 780         }
 781
 782         i2c->ioarea = request_mem_region(res->start, (res->end-res->start)+1,
 783                                          pdev->name);
 784
 785         if (i2c->ioarea == NULL) {
 786                 dev_err(&pdev->dev, "cannot request IO\n");
 787                 ret = -ENXIO;
 788                 goto err_clk;
 789         }
 790
 791         i2c->regs = ioremap(res->start, (res->end-res->start)+1);
 792
 793         if (i2c->regs == NULL) {
 794                 dev_err(&pdev->dev, "cannot map IO\n");
 795                 ret = -ENXIO;
 796                 goto err_ioarea;
 797         }
 798
 799         dev_dbg(&pdev->dev, "registers %p (%p, %p)\n", i2c->regs, i2c->ioarea, res);
 800
 801         /* setup info block for the i2c core */
 802
 803         i2c->adap.algo_data = i2c;
 804         i2c->adap.dev.parent = &pdev->dev;
 805
 806         /* initialise the i2c controller */
 807
 808         ret = s3c24xx_i2c_init(i2c);
 809         if (ret != 0)
 810                 goto err_iomap;
 811
 812         /* find the IRQ for this unit (note, this relies on the init call to
 813          * ensure no current IRQs pending
 814          */
 815
 816         res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
 817         if (res == NULL) {
 818                 dev_err(&pdev->dev, "cannot find IRQ\n");
 819                 ret = -ENOENT;
 820                 goto err_iomap;
 821         }
 822
 823         ret = request_irq(res->start, s3c24xx_i2c_irq, IRQF_DISABLED,
 824                           pdev->name, i2c);
 825
 826         if (ret != 0) {
 827                 dev_err(&pdev->dev, "cannot claim IRQ\n");
 828                 goto err_iomap;
 829         }
 830
 831         i2c->irq = res;
 832
 833         dev_dbg(&pdev->dev, "irq resource %p (%lu)\n", res,
 834                 (unsigned long)res->start);
 835
 836         ret = i2c_add_adapter(&i2c->adap);
 837         if (ret < 0) {
 838                 dev_err(&pdev->dev, "failed to add bus to i2c core\n");
 839                 goto err_irq;
 840         }
 841
 842         platform_set_drvdata(pdev, i2c);
 843
 844         dev_info(&pdev->dev, "%s: S3C I2C adapter\n", i2c->adap.dev.bus_id);
 845         return 0;
 846
 847  err_irq:
 848         free_irq(i2c->irq->start, i2c);
 849
 850  err_iomap:
 851         iounmap(i2c->regs);
 852
 853  err_ioarea:
 854         release_resource(i2c->ioarea);
 855         kfree(i2c->ioarea);
 856
 857  err_clk:
 858         clk_disable(i2c->clk);
 859         clk_put(i2c->clk);
 860
 861  err_noclk:
 862         return ret;
 863 }
 864
 865 /* s3c24xx_i2c_remove
 866  *
 867  * called when device is removed from the bus
 868 */
 869
 870 static int s3c24xx_i2c_remove(struct platform_device *pdev)
 871 {
 872         struct s3c24xx_i2c *i2c = platform_get_drvdata(pdev);
 873
 874         i2c_del_adapter(&i2c->adap);
 875         free_irq(i2c->irq->start, i2c);
 876
 877         clk_disable(i2c->clk);
 878         clk_put(i2c->clk);
 879
 880         iounmap(i2c->regs);
 881
 882         release_resource(i2c->ioarea);
 883         kfree(i2c->ioarea);
 884
 885         return 0;
 886 }
 887
 888 #ifdef CONFIG_PM
 889 static int s3c24xx_i2c_resume(struct platform_device *dev)
 890 {
 891         struct s3c24xx_i2c *i2c = platform_get_drvdata(dev);
 892
 893         if (i2c != NULL)
 894                 s3c24xx_i2c_init(i2c);
 895
 896         return 0;
 897 }
 898
 899 #else
 900 #define s3c24xx_i2c_resume NULL
 901 #endif
 902
 903 /* device driver for platform bus bits */
 904
 905 static struct platform_driver s3c2410_i2c_driver = {
 906         .probe          = s3c24xx_i2c_probe,
 907         .remove         = s3c24xx_i2c_remove,
 908         .resume         = s3c24xx_i2c_resume,
 909         .driver         = {
 910                 .owner  = THIS_MODULE,
 911                 .name   = "s3c2410-i2c",
 912         },
 913 };
 914
 915 static struct platform_driver s3c2440_i2c_driver = {
 916         .probe          = s3c24xx_i2c_probe,
 917         .remove         = s3c24xx_i2c_remove,
 918         .resume         = s3c24xx_i2c_resume,
 919         .driver         = {
 920                 .owner  = THIS_MODULE,
 921                 .name   = "s3c2440-i2c",
 922         },
 923 };
 924
 925 static int __init i2c_adap_s3c_init(void)
 926 {
 927         int ret;
 928
 929         ret = platform_driver_register(&s3c2410_i2c_driver);
 930         if (ret == 0) {
 931                 ret = platform_driver_register(&s3c2440_i2c_driver);
 932                 if (ret)
 933                         platform_driver_unregister(&s3c2410_i2c_driver);
 934         }
 935
 936         return ret;
 937 }
 938
 939 static void __exit i2c_adap_s3c_exit(void)
 940 {
 941         platform_driver_unregister(&s3c2410_i2c_driver);
 942         platform_driver_unregister(&s3c2440_i2c_driver);
 943 }
 944
 945 module_init(i2c_adap_s3c_init);
 946 module_exit(i2c_adap_s3c_exit);
 947
 948 MODULE_DESCRIPTION("S3C24XX I2C Bus driver");
 949 MODULE_AUTHOR("Ben Dooks, <ben@simtec.co.uk>");
 950 MODULE_LICENSE("GPL");