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 #include <linux/cpufreq.h>
  37
  38 #include <mach/hardware.h>
  39 #include <asm/irq.h>
  40 #include <asm/io.h>
  41
  42 #include <mach/regs-gpio.h>
  43 #include <plat/regs-iic.h>
  44 #include <plat/iic.h>
  45
  46 /* i2c controller state */
  47
  48 enum s3c24xx_i2c_state {
  49         STATE_IDLE,
  50         STATE_START,
  51         STATE_READ,
  52         STATE_WRITE,
  53         STATE_STOP
  54 };
  55
  56 struct s3c24xx_i2c {
  57         spinlock_t              lock;
  58         wait_queue_head_t       wait;
  59         unsigned int            suspended:1;
  60
  61         struct i2c_msg          *msg;
  62         unsigned int            msg_num;
  63         unsigned int            msg_idx;
  64         unsigned int            msg_ptr;
  65
  66         unsigned int            tx_setup;
  67
  68         enum s3c24xx_i2c_state  state;
  69         unsigned long           clkrate;
  70
  71         void __iomem            *regs;
  72         struct clk              *clk;
  73         struct device           *dev;
  74         struct resource         *irq;
  75         struct resource         *ioarea;
  76         struct i2c_adapter      adap;
  77
  78 #ifdef CONFIG_CPU_FREQ
  79         struct notifier_block   freq_transition;
  80 #endif
  81 };
  82
  83 /* default platform data to use if not supplied in the platform_device
  84 */
  85
  86 static struct s3c2410_platform_i2c s3c24xx_i2c_default_platform = {
  87         .flags          = 0,
  88         .slave_addr     = 0x10,
  89         .bus_freq       = 100*1000,
  90         .max_freq       = 400*1000,
  91         .sda_delay      = S3C2410_IICLC_SDA_DELAY5 | S3C2410_IICLC_FILTER_ON,
  92 };
  93
  94 /* s3c24xx_i2c_is2440()
  95  *
  96  * return true is this is an s3c2440
  97 */
  98
  99 static inline int s3c24xx_i2c_is2440(struct s3c24xx_i2c *i2c)
 100 {
 101         struct platform_device *pdev = to_platform_device(i2c->dev);
 102
 103         return !strcmp(pdev->name, "s3c2440-i2c");
 104 }
 105
 106
 107 /* s3c24xx_i2c_get_platformdata
 108  *
 109  * get the platform data associated with the given device, or return
 110  * the default if there is none
 111 */
 112
 113 static inline struct s3c2410_platform_i2c *s3c24xx_i2c_get_platformdata(struct device *dev)
 114 {
 115         if (dev->platform_data != NULL)
 116                 return (struct s3c2410_platform_i2c *)dev->platform_data;
 117
 118         return &s3c24xx_i2c_default_platform;
 119 }
 120
 121 /* s3c24xx_i2c_master_complete
 122  *
 123  * complete the message and wake up the caller, using the given return code,
 124  * or zero to mean ok.
 125 */
 126
 127 static inline void s3c24xx_i2c_master_complete(struct s3c24xx_i2c *i2c, int ret)
 128 {
 129         dev_dbg(i2c->dev, "master_complete %d\n", ret);
 130
 131         i2c->msg_ptr = 0;
 132         i2c->msg = NULL;
 133         i2c->msg_idx ++;
 134         i2c->msg_num = 0;
 135         if (ret)
 136                 i2c->msg_idx = ret;
 137
 138         wake_up(&i2c->wait);
 139 }
 140
 141 static inline void s3c24xx_i2c_disable_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 static inline void s3c24xx_i2c_enable_ack(struct s3c24xx_i2c *i2c)
 151 {
 152         unsigned long tmp;
 153
 154         tmp = readl(i2c->regs + S3C2410_IICCON);
 155         writel(tmp | S3C2410_IICCON_ACKEN, i2c->regs + S3C2410_IICCON);
 156
 157 }
 158
 159 /* irq enable/disable functions */
 160
 161 static inline void s3c24xx_i2c_disable_irq(struct s3c24xx_i2c *i2c)
 162 {
 163         unsigned long tmp;
 164
 165         tmp = readl(i2c->regs + S3C2410_IICCON);
 166         writel(tmp & ~S3C2410_IICCON_IRQEN, i2c->regs + S3C2410_IICCON);
 167 }
 168
 169 static inline void s3c24xx_i2c_enable_irq(struct s3c24xx_i2c *i2c)
 170 {
 171         unsigned long tmp;
 172
 173         tmp = readl(i2c->regs + S3C2410_IICCON);
 174         writel(tmp | S3C2410_IICCON_IRQEN, i2c->regs + S3C2410_IICCON);
 175 }
 176
 177
 178 /* s3c24xx_i2c_message_start
 179  *
 180  * put the start of a message onto the bus
 181 */
 182
 183 static void s3c24xx_i2c_message_start(struct s3c24xx_i2c *i2c,
 184                                       struct i2c_msg *msg)
 185 {
 186         unsigned int addr = (msg->addr & 0x7f) << 1;
 187         unsigned long stat;
 188         unsigned long iiccon;
 189
 190         stat = 0;
 191         stat |=  S3C2410_IICSTAT_TXRXEN;
 192
 193         if (msg->flags & I2C_M_RD) {
 194                 stat |= S3C2410_IICSTAT_MASTER_RX;
 195                 addr |= 1;
 196         } else
 197                 stat |= S3C2410_IICSTAT_MASTER_TX;
 198
 199         if (msg->flags & I2C_M_REV_DIR_ADDR)
 200                 addr ^= 1;
 201
 202         // todo - check for wether ack wanted or not
 203         s3c24xx_i2c_enable_ack(i2c);
 204
 205         iiccon = readl(i2c->regs + S3C2410_IICCON);
 206         writel(stat, i2c->regs + S3C2410_IICSTAT);
 207
 208         dev_dbg(i2c->dev, "START: %08lx to IICSTAT, %02x to DS\n", stat, addr);
 209         writeb(addr, i2c->regs + S3C2410_IICDS);
 210
 211         /* delay here to ensure the data byte has gotten onto the bus
 212          * before the transaction is started */
 213
 214         ndelay(i2c->tx_setup);
 215
 216         dev_dbg(i2c->dev, "iiccon, %08lx\n", iiccon);
 217         writel(iiccon, i2c->regs + S3C2410_IICCON);
 218
 219         stat |=  S3C2410_IICSTAT_START;
 220         writel(stat, i2c->regs + S3C2410_IICSTAT);
 221 }
 222
 223 static inline void s3c24xx_i2c_stop(struct s3c24xx_i2c *i2c, int ret)
 224 {
 225         unsigned long iicstat = readl(i2c->regs + S3C2410_IICSTAT);
 226
 227         dev_dbg(i2c->dev, "STOP\n");
 228
 229         /* stop the transfer */
 230         iicstat &= ~ S3C2410_IICSTAT_START;
 231         writel(iicstat, i2c->regs + S3C2410_IICSTAT);
 232
 233         i2c->state = STATE_STOP;
 234
 235         s3c24xx_i2c_master_complete(i2c, ret);
 236         s3c24xx_i2c_disable_irq(i2c);
 237 }
 238
 239 /* helper functions to determine the current state in the set of
 240  * messages we are sending */
 241
 242 /* is_lastmsg()
 243  *
 244  * returns TRUE if the current message is the last in the set
 245 */
 246
 247 static inline int is_lastmsg(struct s3c24xx_i2c *i2c)
 248 {
 249         return i2c->msg_idx >= (i2c->msg_num - 1);
 250 }
 251
 252 /* is_msglast
 253  *
 254  * returns TRUE if we this is the last byte in the current message
 255 */
 256
 257 static inline int is_msglast(struct s3c24xx_i2c *i2c)
 258 {
 259         return i2c->msg_ptr == i2c->msg->len-1;
 260 }
 261
 262 /* is_msgend
 263  *
 264  * returns TRUE if we reached the end of the current message
 265 */
 266
 267 static inline int is_msgend(struct s3c24xx_i2c *i2c)
 268 {
 269         return i2c->msg_ptr >= i2c->msg->len;
 270 }
 271
 272 /* i2s_s3c_irq_nextbyte
 273  *
 274  * process an interrupt and work out what to do
 275  */
 276
 277 static int i2s_s3c_irq_nextbyte(struct s3c24xx_i2c *i2c, unsigned long iicstat)
 278 {
 279         unsigned long tmp;
 280         unsigned char byte;
 281         int ret = 0;
 282
 283         switch (i2c->state) {
 284
 285         case STATE_IDLE:
 286                 dev_err(i2c->dev, "%s: called in STATE_IDLE\n", __func__);
 287                 goto out;
 288                 break;
 289
 290         case STATE_STOP:
 291                 dev_err(i2c->dev, "%s: called in STATE_STOP\n", __func__);
 292                 s3c24xx_i2c_disable_irq(i2c);
 293                 goto out_ack;
 294
 295         case STATE_START:
 296                 /* last thing we did was send a start condition on the
 297                  * bus, or started a new i2c message
 298                  */
 299
 300                 if (iicstat & S3C2410_IICSTAT_LASTBIT &&
 301                     !(i2c->msg->flags & I2C_M_IGNORE_NAK)) {
 302                         /* ack was not received... */
 303
 304                         dev_dbg(i2c->dev, "ack was not received\n");
 305                         s3c24xx_i2c_stop(i2c, -ENXIO);
 306                         goto out_ack;
 307                 }
 308
 309                 if (i2c->msg->flags & I2C_M_RD)
 310                         i2c->state = STATE_READ;
 311                 else
 312                         i2c->state = STATE_WRITE;
 313
 314                 /* terminate the transfer if there is nothing to do
 315                  * as this is used by the i2c probe to find devices. */
 316
 317                 if (is_lastmsg(i2c) && i2c->msg->len == 0) {
 318                         s3c24xx_i2c_stop(i2c, 0);
 319                         goto out_ack;
 320                 }
 321
 322                 if (i2c->state == STATE_READ)
 323                         goto prepare_read;
 324
 325                 /* fall through to the write state, as we will need to
 326                  * send a byte as well */
 327
 328         case STATE_WRITE:
 329                 /* we are writing data to the device... check for the
 330                  * end of the message, and if so, work out what to do
 331                  */
 332
 333                 if (!(i2c->msg->flags & I2C_M_IGNORE_NAK)) {
 334                         if (iicstat & S3C2410_IICSTAT_LASTBIT) {
 335                                 dev_dbg(i2c->dev, "WRITE: No Ack\n");
 336
 337                                 s3c24xx_i2c_stop(i2c, -ECONNREFUSED);
 338                                 goto out_ack;
 339                         }
 340                 }
 341
 342         retry_write:
 343
 344                 if (!is_msgend(i2c)) {
 345                         byte = i2c->msg->buf[i2c->msg_ptr++];
 346                         writeb(byte, i2c->regs + S3C2410_IICDS);
 347
 348                         /* delay after writing the byte to allow the
 349                          * data setup time on the bus, as writing the
 350                          * data to the register causes the first bit
 351                          * to appear on SDA, and SCL will change as
 352                          * soon as the interrupt is acknowledged */
 353
 354                         ndelay(i2c->tx_setup);
 355
 356                 } else if (!is_lastmsg(i2c)) {
 357                         /* we need to go to the next i2c message */
 358
 359                         dev_dbg(i2c->dev, "WRITE: Next Message\n");
 360
 361                         i2c->msg_ptr = 0;
 362                         i2c->msg_idx ++;
 363                         i2c->msg++;
 364
 365                         /* check to see if we need to do another message */
 366                         if (i2c->msg->flags & I2C_M_NOSTART) {
 367
 368                                 if (i2c->msg->flags & I2C_M_RD) {
 369                                         /* cannot do this, the controller
 370                                          * forces us to send a new START
 371                                          * when we change direction */
 372
 373                                         s3c24xx_i2c_stop(i2c, -EINVAL);
 374                                 }
 375
 376                                 goto retry_write;
 377                         } else {
 378
 379                                 /* send the new start */
 380                                 s3c24xx_i2c_message_start(i2c, i2c->msg);
 381                                 i2c->state = STATE_START;
 382                         }
 383
 384                 } else {
 385                         /* send stop */
 386
 387                         s3c24xx_i2c_stop(i2c, 0);
 388                 }
 389                 break;
 390
 391         case STATE_READ:
 392                 /* we have a byte of data in the data register, do
 393                  * something with it, and then work out wether we are
 394                  * going to do any more read/write
 395                  */
 396
 397                 byte = readb(i2c->regs + S3C2410_IICDS);
 398                 i2c->msg->buf[i2c->msg_ptr++] = byte;
 399
 400         prepare_read:
 401                 if (is_msglast(i2c)) {
 402                         /* last byte of buffer */
 403
 404                         if (is_lastmsg(i2c))
 405                                 s3c24xx_i2c_disable_ack(i2c);
 406
 407                 } else if (is_msgend(i2c)) {
 408                         /* ok, we've read the entire buffer, see if there
 409                          * is anything else we need to do */
 410
 411                         if (is_lastmsg(i2c)) {
 412                                 /* last message, send stop and complete */
 413                                 dev_dbg(i2c->dev, "READ: Send Stop\n");
 414
 415                                 s3c24xx_i2c_stop(i2c, 0);
 416                         } else {
 417                                 /* go to the next transfer */
 418                                 dev_dbg(i2c->dev, "READ: Next Transfer\n");
 419
 420                                 i2c->msg_ptr = 0;
 421                                 i2c->msg_idx++;
 422                                 i2c->msg++;
 423                         }
 424                 }
 425
 426                 break;
 427         }
 428
 429         /* acknowlegde the IRQ and get back on with the work */
 430
 431  out_ack:
 432         tmp = readl(i2c->regs + S3C2410_IICCON);
 433         tmp &= ~S3C2410_IICCON_IRQPEND;
 434         writel(tmp, i2c->regs + S3C2410_IICCON);
 435  out:
 436         return ret;
 437 }
 438
 439 /* s3c24xx_i2c_irq
 440  *
 441  * top level IRQ servicing routine
 442 */
 443
 444 static irqreturn_t s3c24xx_i2c_irq(int irqno, void *dev_id)
 445 {
 446         struct s3c24xx_i2c *i2c = dev_id;
 447         unsigned long status;
 448         unsigned long tmp;
 449
 450         status = readl(i2c->regs + S3C2410_IICSTAT);
 451
 452         if (status & S3C2410_IICSTAT_ARBITR) {
 453                 // deal with arbitration loss
 454                 dev_err(i2c->dev, "deal with arbitration loss\n");
 455         }
 456
 457         if (i2c->state == STATE_IDLE) {
 458                 dev_dbg(i2c->dev, "IRQ: error i2c->state == IDLE\n");
 459
 460                 tmp = readl(i2c->regs + S3C2410_IICCON);
 461                 tmp &= ~S3C2410_IICCON_IRQPEND;
 462                 writel(tmp, i2c->regs +  S3C2410_IICCON);
 463                 goto out;
 464         }
 465
 466         /* pretty much this leaves us with the fact that we've
 467          * transmitted or received whatever byte we last sent */
 468
 469         i2s_s3c_irq_nextbyte(i2c, status);
 470
 471  out:
 472         return IRQ_HANDLED;
 473 }
 474
 475
 476 /* s3c24xx_i2c_set_master
 477  *
 478  * get the i2c bus for a master transaction
 479 */
 480
 481 static int s3c24xx_i2c_set_master(struct s3c24xx_i2c *i2c)
 482 {
 483         unsigned long iicstat;
 484         int timeout = 400;
 485
 486         while (timeout-- > 0) {
 487                 iicstat = readl(i2c->regs + S3C2410_IICSTAT);
 488
 489                 if (!(iicstat & S3C2410_IICSTAT_BUSBUSY))
 490                         return 0;
 491
 492                 msleep(1);
 493         }
 494
 495         dev_dbg(i2c->dev, "timeout: GPEDAT is %08x\n",
 496                 __raw_readl(S3C2410_GPEDAT));
 497
 498         return -ETIMEDOUT;
 499 }
 500
 501 /* s3c24xx_i2c_doxfer
 502  *
 503  * this starts an i2c transfer
 504 */
 505
 506 static int s3c24xx_i2c_doxfer(struct s3c24xx_i2c *i2c, struct i2c_msg *msgs, int num)
 507 {
 508         unsigned long timeout;
 509         int ret;
 510
 511         if (i2c->suspended)
 512                 return -EIO;
 513
 514         ret = s3c24xx_i2c_set_master(i2c);
 515         if (ret != 0) {
 516                 dev_err(i2c->dev, "cannot get bus (error %d)\n", ret);
 517                 ret = -EAGAIN;
 518                 goto out;
 519         }
 520
 521         spin_lock_irq(&i2c->lock);
 522
 523         i2c->msg     = msgs;
 524         i2c->msg_num = num;
 525         i2c->msg_ptr = 0;
 526         i2c->msg_idx = 0;
 527         i2c->state   = STATE_START;
 528
 529         s3c24xx_i2c_enable_irq(i2c);
 530         s3c24xx_i2c_message_start(i2c, msgs);
 531         spin_unlock_irq(&i2c->lock);
 532
 533         timeout = wait_event_timeout(i2c->wait, i2c->msg_num == 0, HZ * 5);
 534
 535         ret = i2c->msg_idx;
 536
 537         /* having these next two as dev_err() makes life very
 538          * noisy when doing an i2cdetect */
 539
 540         if (timeout == 0)
 541                 dev_dbg(i2c->dev, "timeout\n");
 542         else if (ret != num)
 543                 dev_dbg(i2c->dev, "incomplete xfer (%d)\n", ret);
 544
 545         /* ensure the stop has been through the bus */
 546
 547         msleep(1);
 548
 549  out:
 550         return ret;
 551 }
 552
 553 /* s3c24xx_i2c_xfer
 554  *
 555  * first port of call from the i2c bus code when an message needs
 556  * transferring across the i2c bus.
 557 */
 558
 559 static int s3c24xx_i2c_xfer(struct i2c_adapter *adap,
 560                         struct i2c_msg *msgs, int num)
 561 {
 562         struct s3c24xx_i2c *i2c = (struct s3c24xx_i2c *)adap->algo_data;
 563         int retry;
 564         int ret;
 565
 566         for (retry = 0; retry < adap->retries; retry++) {
 567
 568                 ret = s3c24xx_i2c_doxfer(i2c, msgs, num);
 569
 570                 if (ret != -EAGAIN)
 571                         return ret;
 572
 573                 dev_dbg(i2c->dev, "Retrying transmission (%d)\n", retry);
 574
 575                 udelay(100);
 576         }
 577
 578         return -EREMOTEIO;
 579 }
 580
 581 /* declare our i2c functionality */
 582 static u32 s3c24xx_i2c_func(struct i2c_adapter *adap)
 583 {
 584         return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_PROTOCOL_MANGLING;
 585 }
 586
 587 /* i2c bus registration info */
 588
 589 static const struct i2c_algorithm s3c24xx_i2c_algorithm = {
 590         .master_xfer            = s3c24xx_i2c_xfer,
 591         .functionality          = s3c24xx_i2c_func,
 592 };
 593
 594 static struct s3c24xx_i2c s3c24xx_i2c = {
 595         .lock           = __SPIN_LOCK_UNLOCKED(s3c24xx_i2c.lock),
 596         .wait           = __WAIT_QUEUE_HEAD_INITIALIZER(s3c24xx_i2c.wait),
 597         .tx_setup       = 50,
 598         .adap           = {
 599                 .name                   = "s3c2410-i2c",
 600                 .owner                  = THIS_MODULE,
 601                 .algo                   = &s3c24xx_i2c_algorithm,
 602                 .retries                = 2,
 603                 .class                  = I2C_CLASS_HWMON | I2C_CLASS_SPD,
 604         },
 605 };
 606
 607 /* s3c24xx_i2c_calcdivisor
 608  *
 609  * return the divisor settings for a given frequency
 610 */
 611
 612 static int s3c24xx_i2c_calcdivisor(unsigned long clkin, unsigned int wanted,
 613                                    unsigned int *div1, unsigned int *divs)
 614 {
 615         unsigned int calc_divs = clkin / wanted;
 616         unsigned int calc_div1;
 617
 618         if (calc_divs > (16*16))
 619                 calc_div1 = 512;
 620         else
 621                 calc_div1 = 16;
 622
 623         calc_divs += calc_div1-1;
 624         calc_divs /= calc_div1;
 625
 626         if (calc_divs == 0)
 627                 calc_divs = 1;
 628         if (calc_divs > 17)
 629                 calc_divs = 17;
 630
 631         *divs = calc_divs;
 632         *div1 = calc_div1;
 633
 634         return clkin / (calc_divs * calc_div1);
 635 }
 636
 637 /* freq_acceptable
 638  *
 639  * test wether a frequency is within the acceptable range of error
 640 */
 641
 642 static inline int freq_acceptable(unsigned int freq, unsigned int wanted)
 643 {
 644         int diff = freq - wanted;
 645
 646         return (diff >= -2 && diff <= 2);
 647 }
 648
 649 /* s3c24xx_i2c_clockrate
 650  *
 651  * work out a divisor for the user requested frequency setting,
 652  * either by the requested frequency, or scanning the acceptable
 653  * range of frequencies until something is found
 654 */
 655
 656 static int s3c24xx_i2c_clockrate(struct s3c24xx_i2c *i2c, unsigned int *got)
 657 {
 658         struct s3c2410_platform_i2c *pdata;
 659         unsigned long clkin = clk_get_rate(i2c->clk);
 660         unsigned int divs, div1;
 661         u32 iiccon;
 662         int freq;
 663         int start, end;
 664
 665         i2c->clkrate = clkin;
 666
 667         pdata = s3c24xx_i2c_get_platformdata(i2c->adap.dev.parent);
 668         clkin /= 1000;          /* clkin now in KHz */
 669
 670         dev_dbg(i2c->dev, "pdata %p, freq %lu %lu..%lu\n",
 671                  pdata, pdata->bus_freq, pdata->min_freq, pdata->max_freq);
 672
 673         if (pdata->bus_freq != 0) {
 674                 freq = s3c24xx_i2c_calcdivisor(clkin, pdata->bus_freq/1000,
 675                                                &div1, &divs);
 676                 if (freq_acceptable(freq, pdata->bus_freq/1000))
 677                         goto found;
 678         }
 679
 680         /* ok, we may have to search for something suitable... */
 681
 682         start = (pdata->max_freq == 0) ? pdata->bus_freq : pdata->max_freq;
 683         end = pdata->min_freq;
 684
 685         start /= 1000;
 686         end /= 1000;
 687
 688         /* search loop... */
 689
 690         for (; start > end; start--) {
 691                 freq = s3c24xx_i2c_calcdivisor(clkin, start, &div1, &divs);
 692                 if (freq_acceptable(freq, start))
 693                         goto found;
 694         }
 695
 696         /* cannot find frequency spec */
 697
 698         return -EINVAL;
 699
 700  found:
 701         *got = freq;
 702
 703         iiccon = readl(i2c->regs + S3C2410_IICCON);
 704         iiccon &= ~(S3C2410_IICCON_SCALEMASK | S3C2410_IICCON_TXDIV_512);
 705         iiccon |= (divs-1);
 706
 707         if (div1 == 512)
 708                 iiccon |= S3C2410_IICCON_TXDIV_512;
 709
 710         writel(iiccon, i2c->regs + S3C2410_IICCON);
 711
 712         return 0;
 713 }
 714
 715 #ifdef CONFIG_CPU_FREQ
 716
 717 #define freq_to_i2c(_n) container_of(_n, struct s3c24xx_i2c, freq_transition)
 718
 719 static int s3c24xx_i2c_cpufreq_transition(struct notifier_block *nb,
 720                                           unsigned long val, void *data)
 721 {
 722         struct s3c24xx_i2c *i2c = freq_to_i2c(nb);
 723         unsigned long flags;
 724         unsigned int got;
 725         int delta_f;
 726         int ret;
 727
 728         delta_f = clk_get_rate(i2c->clk) - i2c->clkrate;
 729
 730         /* if we're post-change and the input clock has slowed down
 731          * or at pre-change and the clock is about to speed up, then
 732          * adjust our clock rate. <0 is slow, >0 speedup.
 733          */
 734
 735         if ((val == CPUFREQ_POSTCHANGE && delta_f < 0) ||
 736             (val == CPUFREQ_PRECHANGE && delta_f > 0)) {
 737                 spin_lock_irqsave(&i2c->lock, flags);
 738                 ret = s3c24xx_i2c_clockrate(i2c, &got);
 739                 spin_unlock_irqrestore(&i2c->lock, flags);
 740
 741                 if (ret < 0)
 742                         dev_err(i2c->dev, "cannot find frequency\n");
 743                 else
 744                         dev_info(i2c->dev, "setting freq %d\n", got);
 745         }
 746
 747         return 0;
 748 }
 749
 750 static inline int s3c24xx_i2c_register_cpufreq(struct s3c24xx_i2c *i2c)
 751 {
 752         i2c->freq_transition.notifier_call = s3c24xx_i2c_cpufreq_transition;
 753
 754         return cpufreq_register_notifier(&i2c->freq_transition,
 755                                          CPUFREQ_TRANSITION_NOTIFIER);
 756 }
 757
 758 static inline void s3c24xx_i2c_deregister_cpufreq(struct s3c24xx_i2c *i2c)
 759 {
 760         cpufreq_unregister_notifier(&i2c->freq_transition,
 761                                     CPUFREQ_TRANSITION_NOTIFIER);
 762 }
 763
 764 #else
 765 static inline int s3c24xx_i2c_register_cpufreq(struct s3c24xx_i2c *i2c)
 766 {
 767         return 0;
 768 }
 769
 770 static inline void s3c24xx_i2c_deregister_cpufreq(struct s3c24xx_i2c *i2c)
 771 {
 772 }
 773 #endif
 774
 775 /* s3c24xx_i2c_init
 776  *
 777  * initialise the controller, set the IO lines and frequency
 778 */
 779
 780 static int s3c24xx_i2c_init(struct s3c24xx_i2c *i2c)
 781 {
 782         unsigned long iicon = S3C2410_IICCON_IRQEN | S3C2410_IICCON_ACKEN;
 783         struct s3c2410_platform_i2c *pdata;
 784         unsigned int freq;
 785
 786         /* get the plafrom data */
 787
 788         pdata = s3c24xx_i2c_get_platformdata(i2c->adap.dev.parent);
 789
 790         /* inititalise the gpio */
 791
 792         s3c2410_gpio_cfgpin(S3C2410_GPE15, S3C2410_GPE15_IICSDA);
 793         s3c2410_gpio_cfgpin(S3C2410_GPE14, S3C2410_GPE14_IICSCL);
 794
 795         /* write slave address */
 796
 797         writeb(pdata->slave_addr, i2c->regs + S3C2410_IICADD);
 798
 799         dev_info(i2c->dev, "slave address 0x%02x\n", pdata->slave_addr);
 800
 801         writel(iicon, i2c->regs + S3C2410_IICCON);
 802
 803         /* we need to work out the divisors for the clock... */
 804
 805         if (s3c24xx_i2c_clockrate(i2c, &freq) != 0) {
 806                 writel(0, i2c->regs + S3C2410_IICCON);
 807                 dev_err(i2c->dev, "cannot meet bus frequency required\n");
 808                 return -EINVAL;
 809         }
 810
 811         /* todo - check that the i2c lines aren't being dragged anywhere */
 812
 813         dev_info(i2c->dev, "bus frequency set to %d KHz\n", freq);
 814         dev_dbg(i2c->dev, "S3C2410_IICCON=0x%02lx\n", iicon);
 815
 816         /* check for s3c2440 i2c controller  */
 817
 818         if (s3c24xx_i2c_is2440(i2c)) {
 819                 dev_dbg(i2c->dev, "S3C2440_IICLC=%08x\n", pdata->sda_delay);
 820
 821                 writel(pdata->sda_delay, i2c->regs + S3C2440_IICLC);
 822         }
 823
 824         return 0;
 825 }
 826
 827 /* s3c24xx_i2c_probe
 828  *
 829  * called by the bus driver when a suitable device is found
 830 */
 831
 832 static int s3c24xx_i2c_probe(struct platform_device *pdev)
 833 {
 834         struct s3c24xx_i2c *i2c = &s3c24xx_i2c;
 835         struct s3c2410_platform_i2c *pdata;
 836         struct resource *res;
 837         int ret;
 838
 839         pdata = s3c24xx_i2c_get_platformdata(&pdev->dev);
 840
 841         /* find the clock and enable it */
 842
 843         i2c->dev = &pdev->dev;
 844         i2c->clk = clk_get(&pdev->dev, "i2c");
 845         if (IS_ERR(i2c->clk)) {
 846                 dev_err(&pdev->dev, "cannot get clock\n");
 847                 ret = -ENOENT;
 848                 goto err_noclk;
 849         }
 850
 851         dev_dbg(&pdev->dev, "clock source %p\n", i2c->clk);
 852
 853         clk_enable(i2c->clk);
 854
 855         /* map the registers */
 856
 857         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 858         if (res == NULL) {
 859                 dev_err(&pdev->dev, "cannot find IO resource\n");
 860                 ret = -ENOENT;
 861                 goto err_clk;
 862         }
 863
 864         i2c->ioarea = request_mem_region(res->start, (res->end-res->start)+1,
 865                                          pdev->name);
 866
 867         if (i2c->ioarea == NULL) {
 868                 dev_err(&pdev->dev, "cannot request IO\n");
 869                 ret = -ENXIO;
 870                 goto err_clk;
 871         }
 872
 873         i2c->regs = ioremap(res->start, (res->end-res->start)+1);
 874
 875         if (i2c->regs == NULL) {
 876                 dev_err(&pdev->dev, "cannot map IO\n");
 877                 ret = -ENXIO;
 878                 goto err_ioarea;
 879         }
 880
 881         dev_dbg(&pdev->dev, "registers %p (%p, %p)\n", i2c->regs, i2c->ioarea, res);
 882
 883         /* setup info block for the i2c core */
 884
 885         i2c->adap.algo_data = i2c;
 886         i2c->adap.dev.parent = &pdev->dev;
 887
 888         /* initialise the i2c controller */
 889
 890         ret = s3c24xx_i2c_init(i2c);
 891         if (ret != 0)
 892                 goto err_iomap;
 893
 894         /* find the IRQ for this unit (note, this relies on the init call to
 895          * ensure no current IRQs pending
 896          */
 897
 898         res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
 899         if (res == NULL) {
 900                 dev_err(&pdev->dev, "cannot find IRQ\n");
 901                 ret = -ENOENT;
 902                 goto err_iomap;
 903         }
 904
 905         ret = request_irq(res->start, s3c24xx_i2c_irq, IRQF_DISABLED,
 906                           pdev->name, i2c);
 907
 908         if (ret != 0) {
 909                 dev_err(&pdev->dev, "cannot claim IRQ\n");
 910                 goto err_iomap;
 911         }
 912
 913         i2c->irq = res;
 914
 915         dev_dbg(&pdev->dev, "irq resource %p (%lu)\n", res,
 916                 (unsigned long)res->start);
 917
 918         ret = s3c24xx_i2c_register_cpufreq(i2c);
 919         if (ret < 0) {
 920                 dev_err(&pdev->dev, "failed to register cpufreq notifier\n");
 921                 goto err_irq;
 922         }
 923
 924         /* Note, previous versions of the driver used i2c_add_adapter()
 925          * to add the bus at any number. We now pass the bus number via
 926          * the platform data, so if unset it will now default to always
 927          * being bus 0.
 928          */
 929
 930         i2c->adap.nr = pdata->bus_num;
 931
 932         ret = i2c_add_numbered_adapter(&i2c->adap);
 933         if (ret < 0) {
 934                 dev_err(&pdev->dev, "failed to add bus to i2c core\n");
 935                 goto err_cpufreq;
 936         }
 937
 938         platform_set_drvdata(pdev, i2c);
 939
 940         dev_info(&pdev->dev, "%s: S3C I2C adapter\n", i2c->adap.dev.bus_id);
 941         return 0;
 942
 943  err_cpufreq:
 944         s3c24xx_i2c_deregister_cpufreq(i2c);
 945
 946  err_irq:
 947         free_irq(i2c->irq->start, i2c);
 948
 949  err_iomap:
 950         iounmap(i2c->regs);
 951
 952  err_ioarea:
 953         release_resource(i2c->ioarea);
 954         kfree(i2c->ioarea);
 955
 956  err_clk:
 957         clk_disable(i2c->clk);
 958         clk_put(i2c->clk);
 959
 960  err_noclk:
 961         return ret;
 962 }
 963
 964 /* s3c24xx_i2c_remove
 965  *
 966  * called when device is removed from the bus
 967 */
 968
 969 static int s3c24xx_i2c_remove(struct platform_device *pdev)
 970 {
 971         struct s3c24xx_i2c *i2c = platform_get_drvdata(pdev);
 972
 973         s3c24xx_i2c_deregister_cpufreq(i2c);
 974
 975         i2c_del_adapter(&i2c->adap);
 976         free_irq(i2c->irq->start, i2c);
 977
 978         clk_disable(i2c->clk);
 979         clk_put(i2c->clk);
 980
 981         iounmap(i2c->regs);
 982
 983         release_resource(i2c->ioarea);
 984         kfree(i2c->ioarea);
 985
 986         return 0;
 987 }
 988
 989 #ifdef CONFIG_PM
 990 static int s3c24xx_i2c_suspend_late(struct platform_device *dev,
 991                                     pm_message_t msg)
 992 {
 993         struct s3c24xx_i2c *i2c = platform_get_drvdata(dev);
 994         i2c->suspended = 1;
 995         return 0;
 996 }
 997
 998 static int s3c24xx_i2c_resume(struct platform_device *dev)
 999 {
1000         struct s3c24xx_i2c *i2c = platform_get_drvdata(dev);
1001
1002         i2c->suspended = 0;
1003         s3c24xx_i2c_init(i2c);
1004
1005         return 0;
1006 }
1007
1008 #else
1009 #define s3c24xx_i2c_suspend_late NULL
1010 #define s3c24xx_i2c_resume NULL
1011 #endif
1012
1013 /* device driver for platform bus bits */
1014
1015 static struct platform_driver s3c2410_i2c_driver = {
1016         .probe          = s3c24xx_i2c_probe,
1017         .remove         = s3c24xx_i2c_remove,
1018         .suspend_late   = s3c24xx_i2c_suspend_late,
1019         .resume         = s3c24xx_i2c_resume,
1020         .driver         = {
1021                 .owner  = THIS_MODULE,
1022                 .name   = "s3c2410-i2c",
1023         },
1024 };
1025
1026 static struct platform_driver s3c2440_i2c_driver = {
1027         .probe          = s3c24xx_i2c_probe,
1028         .remove         = s3c24xx_i2c_remove,
1029         .suspend_late   = s3c24xx_i2c_suspend_late,
1030         .resume         = s3c24xx_i2c_resume,
1031         .driver         = {
1032                 .owner  = THIS_MODULE,
1033                 .name   = "s3c2440-i2c",
1034         },
1035 };
1036
1037 static int __init i2c_adap_s3c_init(void)
1038 {
1039         int ret;
1040
1041         ret = platform_driver_register(&s3c2410_i2c_driver);
1042         if (ret == 0) {
1043                 ret = platform_driver_register(&s3c2440_i2c_driver);
1044                 if (ret)
1045                         platform_driver_unregister(&s3c2410_i2c_driver);
1046         }
1047
1048         return ret;
1049 }
1050
1051 static void __exit i2c_adap_s3c_exit(void)
1052 {
1053         platform_driver_unregister(&s3c2410_i2c_driver);
1054         platform_driver_unregister(&s3c2440_i2c_driver);
1055 }
1056
1057 module_init(i2c_adap_s3c_init);
1058 module_exit(i2c_adap_s3c_exit);
1059
1060 MODULE_DESCRIPTION("S3C24XX I2C Bus driver");
1061 MODULE_AUTHOR("Ben Dooks, <ben@simtec.co.uk>");
1062 MODULE_LICENSE("GPL");
1063 MODULE_ALIAS("platform:s3c2410-i2c");
1064 MODULE_ALIAS("platform:s3c2440-i2c");