drivers/i2c/busses/i2c-s3c2410.c

   1 /* linux/drivers/i2c/busses/i2c-s3c2410.c
   2  *
   3  * Copyright (C) 2004,2005,2009 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/init.h>
  28 #include <linux/time.h>
  29 #include <linux/interrupt.h>
  30 #include <linux/delay.h>
  31 #include <linux/errno.h>
  32 #include <linux/err.h>
  33 #include <linux/platform_device.h>
  34 #include <linux/clk.h>
  35 #include <linux/cpufreq.h>
  36 #include <linux/slab.h>
  37 #include <linux/io.h>
  38
  39 #include <asm/irq.h>
  40
  41 #include <plat/regs-iic.h>
  42 #include <plat/iic.h>
  43
  44 /* i2c controller state */
  45
  46 enum s3c24xx_i2c_state {
  47         STATE_IDLE,
  48         STATE_START,
  49         STATE_READ,
  50         STATE_WRITE,
  51         STATE_STOP
  52 };
  53
  54 enum s3c24xx_i2c_type {
  55         TYPE_S3C2410,
  56         TYPE_S3C2440,
  57 };
  58
  59 struct s3c24xx_i2c {
  60         spinlock_t              lock;
  61         wait_queue_head_t       wait;
  62         unsigned int            suspended:1;
  63
  64         struct i2c_msg          *msg;
  65         unsigned int            msg_num;
  66         unsigned int            msg_idx;
  67         unsigned int            msg_ptr;
  68
  69         unsigned int            tx_setup;
  70         unsigned int            irq;
  71
  72         enum s3c24xx_i2c_state  state;
  73         unsigned long           clkrate;
  74
  75         void __iomem            *regs;
  76         struct clk              *clk;
  77         struct device           *dev;
  78         struct resource         *ioarea;
  79         struct i2c_adapter      adap;
  80
  81 #ifdef CONFIG_CPU_FREQ
  82         struct notifier_block   freq_transition;
  83 #endif
  84 };
  85
  86 /* default platform data removed, dev should always carry data. */
  87
  88 /* s3c24xx_i2c_is2440()
  89  *
  90  * return true is this is an s3c2440
  91 */
  92
  93 static inline int s3c24xx_i2c_is2440(struct s3c24xx_i2c *i2c)
  94 {
  95         struct platform_device *pdev = to_platform_device(i2c->dev);
  96         enum s3c24xx_i2c_type type;
  97
  98         type = platform_get_device_id(pdev)->driver_data;
  99         return type == TYPE_S3C2440;
 100 }
 101
 102 /* s3c24xx_i2c_master_complete
 103  *
 104  * complete the message and wake up the caller, using the given return code,
 105  * or zero to mean ok.
 106 */
 107
 108 static inline void s3c24xx_i2c_master_complete(struct s3c24xx_i2c *i2c, int ret)
 109 {
 110         dev_dbg(i2c->dev, "master_complete %d\n", ret);
 111
 112         i2c->msg_ptr = 0;
 113         i2c->msg = NULL;
 114         i2c->msg_idx++;
 115         i2c->msg_num = 0;
 116         if (ret)
 117                 i2c->msg_idx = ret;
 118
 119         wake_up(&i2c->wait);
 120 }
 121
 122 static inline void s3c24xx_i2c_disable_ack(struct s3c24xx_i2c *i2c)
 123 {
 124         unsigned long tmp;
 125
 126         tmp = readl(i2c->regs + S3C2410_IICCON);
 127         writel(tmp & ~S3C2410_IICCON_ACKEN, i2c->regs + S3C2410_IICCON);
 128 }
 129
 130 static inline void s3c24xx_i2c_enable_ack(struct s3c24xx_i2c *i2c)
 131 {
 132         unsigned long tmp;
 133
 134         tmp = readl(i2c->regs + S3C2410_IICCON);
 135         writel(tmp | S3C2410_IICCON_ACKEN, i2c->regs + S3C2410_IICCON);
 136 }
 137
 138 /* irq enable/disable functions */
 139
 140 static inline void s3c24xx_i2c_disable_irq(struct s3c24xx_i2c *i2c)
 141 {
 142         unsigned long tmp;
 143
 144         tmp = readl(i2c->regs + S3C2410_IICCON);
 145         writel(tmp & ~S3C2410_IICCON_IRQEN, i2c->regs + S3C2410_IICCON);
 146 }
 147
 148 static inline void s3c24xx_i2c_enable_irq(struct s3c24xx_i2c *i2c)
 149 {
 150         unsigned long tmp;
 151
 152         tmp = readl(i2c->regs + S3C2410_IICCON);
 153         writel(tmp | S3C2410_IICCON_IRQEN, i2c->regs + S3C2410_IICCON);
 154 }
 155
 156
 157 /* s3c24xx_i2c_message_start
 158  *
 159  * put the start of a message onto the bus
 160 */
 161
 162 static void s3c24xx_i2c_message_start(struct s3c24xx_i2c *i2c,
 163                                       struct i2c_msg *msg)
 164 {
 165         unsigned int addr = (msg->addr & 0x7f) << 1;
 166         unsigned long stat;
 167         unsigned long iiccon;
 168
 169         stat = 0;
 170         stat |=  S3C2410_IICSTAT_TXRXEN;
 171
 172         if (msg->flags & I2C_M_RD) {
 173                 stat |= S3C2410_IICSTAT_MASTER_RX;
 174                 addr |= 1;
 175         } else
 176                 stat |= S3C2410_IICSTAT_MASTER_TX;
 177
 178         if (msg->flags & I2C_M_REV_DIR_ADDR)
 179                 addr ^= 1;
 180
 181         /* todo - check for wether ack wanted or not */
 182         s3c24xx_i2c_enable_ack(i2c);
 183
 184         iiccon = readl(i2c->regs + S3C2410_IICCON);
 185         writel(stat, i2c->regs + S3C2410_IICSTAT);
 186
 187         dev_dbg(i2c->dev, "START: %08lx to IICSTAT, %02x to DS\n", stat, addr);
 188         writeb(addr, i2c->regs + S3C2410_IICDS);
 189
 190         /* delay here to ensure the data byte has gotten onto the bus
 191          * before the transaction is started */
 192
 193         ndelay(i2c->tx_setup);
 194
 195         dev_dbg(i2c->dev, "iiccon, %08lx\n", iiccon);
 196         writel(iiccon, i2c->regs + S3C2410_IICCON);
 197
 198         stat |= S3C2410_IICSTAT_START;
 199         writel(stat, i2c->regs + S3C2410_IICSTAT);
 200 }
 201
 202 static inline void s3c24xx_i2c_stop(struct s3c24xx_i2c *i2c, int ret)
 203 {
 204         unsigned long iicstat = readl(i2c->regs + S3C2410_IICSTAT);
 205
 206         dev_dbg(i2c->dev, "STOP\n");
 207
 208         /* stop the transfer */
 209         iicstat &= ~S3C2410_IICSTAT_START;
 210         writel(iicstat, i2c->regs + S3C2410_IICSTAT);
 211
 212         i2c->state = STATE_STOP;
 213
 214         s3c24xx_i2c_master_complete(i2c, ret);
 215         s3c24xx_i2c_disable_irq(i2c);
 216 }
 217
 218 /* helper functions to determine the current state in the set of
 219  * messages we are sending */
 220
 221 /* is_lastmsg()
 222  *
 223  * returns TRUE if the current message is the last in the set
 224 */
 225
 226 static inline int is_lastmsg(struct s3c24xx_i2c *i2c)
 227 {
 228         return i2c->msg_idx >= (i2c->msg_num - 1);
 229 }
 230
 231 /* is_msglast
 232  *
 233  * returns TRUE if we this is the last byte in the current message
 234 */
 235
 236 static inline int is_msglast(struct s3c24xx_i2c *i2c)
 237 {
 238         return i2c->msg_ptr == i2c->msg->len-1;
 239 }
 240
 241 /* is_msgend
 242  *
 243  * returns TRUE if we reached the end of the current message
 244 */
 245
 246 static inline int is_msgend(struct s3c24xx_i2c *i2c)
 247 {
 248         return i2c->msg_ptr >= i2c->msg->len;
 249 }
 250
 251 /* i2s_s3c_irq_nextbyte
 252  *
 253  * process an interrupt and work out what to do
 254  */
 255
 256 static int i2s_s3c_irq_nextbyte(struct s3c24xx_i2c *i2c, unsigned long iicstat)
 257 {
 258         unsigned long tmp;
 259         unsigned char byte;
 260         int ret = 0;
 261
 262         switch (i2c->state) {
 263
 264         case STATE_IDLE:
 265                 dev_err(i2c->dev, "%s: called in STATE_IDLE\n", __func__);
 266                 goto out;
 267                 break;
 268
 269         case STATE_STOP:
 270                 dev_err(i2c->dev, "%s: called in STATE_STOP\n", __func__);
 271                 s3c24xx_i2c_disable_irq(i2c);
 272                 goto out_ack;
 273
 274         case STATE_START:
 275                 /* last thing we did was send a start condition on the
 276                  * bus, or started a new i2c message
 277                  */
 278
 279                 if (iicstat & S3C2410_IICSTAT_LASTBIT &&
 280                     !(i2c->msg->flags & I2C_M_IGNORE_NAK)) {
 281                         /* ack was not received... */
 282
 283                         dev_dbg(i2c->dev, "ack was not received\n");
 284                         s3c24xx_i2c_stop(i2c, -ENXIO);
 285                         goto out_ack;
 286                 }
 287
 288                 if (i2c->msg->flags & I2C_M_RD)
 289                         i2c->state = STATE_READ;
 290                 else
 291                         i2c->state = STATE_WRITE;
 292
 293                 /* terminate the transfer if there is nothing to do
 294                  * as this is used by the i2c probe to find devices. */
 295
 296                 if (is_lastmsg(i2c) && i2c->msg->len == 0) {
 297                         s3c24xx_i2c_stop(i2c, 0);
 298                         goto out_ack;
 299                 }
 300
 301                 if (i2c->state == STATE_READ)
 302                         goto prepare_read;
 303
 304                 /* fall through to the write state, as we will need to
 305                  * send a byte as well */
 306
 307         case STATE_WRITE:
 308                 /* we are writing data to the device... check for the
 309                  * end of the message, and if so, work out what to do
 310                  */
 311
 312                 if (!(i2c->msg->flags & I2C_M_IGNORE_NAK)) {
 313                         if (iicstat & S3C2410_IICSTAT_LASTBIT) {
 314                                 dev_dbg(i2c->dev, "WRITE: No Ack\n");
 315
 316                                 s3c24xx_i2c_stop(i2c, -ECONNREFUSED);
 317                                 goto out_ack;
 318                         }
 319                 }
 320
 321  retry_write:
 322
 323                 if (!is_msgend(i2c)) {
 324                         byte = i2c->msg->buf[i2c->msg_ptr++];
 325                         writeb(byte, i2c->regs + S3C2410_IICDS);
 326
 327                         /* delay after writing the byte to allow the
 328                          * data setup time on the bus, as writing the
 329                          * data to the register causes the first bit
 330                          * to appear on SDA, and SCL will change as
 331                          * soon as the interrupt is acknowledged */
 332
 333                         ndelay(i2c->tx_setup);
 334
 335                 } else if (!is_lastmsg(i2c)) {
 336                         /* we need to go to the next i2c message */
 337
 338                         dev_dbg(i2c->dev, "WRITE: Next Message\n");
 339
 340                         i2c->msg_ptr = 0;
 341                         i2c->msg_idx++;
 342                         i2c->msg++;
 343
 344                         /* check to see if we need to do another message */
 345                         if (i2c->msg->flags & I2C_M_NOSTART) {
 346
 347                                 if (i2c->msg->flags & I2C_M_RD) {
 348                                         /* cannot do this, the controller
 349                                          * forces us to send a new START
 350                                          * when we change direction */
 351
 352                                         s3c24xx_i2c_stop(i2c, -EINVAL);
 353                                 }
 354
 355                                 goto retry_write;
 356                         } else {
 357                                 /* send the new start */
 358                                 s3c24xx_i2c_message_start(i2c, i2c->msg);
 359                                 i2c->state = STATE_START;
 360                         }
 361
 362                 } else {
 363                         /* send stop */
 364
 365                         s3c24xx_i2c_stop(i2c, 0);
 366                 }
 367                 break;
 368
 369         case STATE_READ:
 370                 /* we have a byte of data in the data register, do
 371                  * something with it, and then work out wether we are
 372                  * going to do any more read/write
 373                  */
 374
 375                 byte = readb(i2c->regs + S3C2410_IICDS);
 376                 i2c->msg->buf[i2c->msg_ptr++] = byte;
 377
 378  prepare_read:
 379                 if (is_msglast(i2c)) {
 380                         /* last byte of buffer */
 381
 382                         if (is_lastmsg(i2c))
 383                                 s3c24xx_i2c_disable_ack(i2c);
 384
 385                 } else if (is_msgend(i2c)) {
 386                         /* ok, we've read the entire buffer, see if there
 387                          * is anything else we need to do */
 388
 389                         if (is_lastmsg(i2c)) {
 390                                 /* last message, send stop and complete */
 391                                 dev_dbg(i2c->dev, "READ: Send Stop\n");
 392
 393                                 s3c24xx_i2c_stop(i2c, 0);
 394                         } else {
 395                                 /* go to the next transfer */
 396                                 dev_dbg(i2c->dev, "READ: Next Transfer\n");
 397
 398                                 i2c->msg_ptr = 0;
 399                                 i2c->msg_idx++;
 400                                 i2c->msg++;
 401                         }
 402                 }
 403
 404                 break;
 405         }
 406
 407         /* acknowlegde the IRQ and get back on with the work */
 408
 409  out_ack:
 410         tmp = readl(i2c->regs + S3C2410_IICCON);
 411         tmp &= ~S3C2410_IICCON_IRQPEND;
 412         writel(tmp, i2c->regs + S3C2410_IICCON);
 413  out:
 414         return ret;
 415 }
 416
 417 /* s3c24xx_i2c_irq
 418  *
 419  * top level IRQ servicing routine
 420 */
 421
 422 static irqreturn_t s3c24xx_i2c_irq(int irqno, void *dev_id)
 423 {
 424         struct s3c24xx_i2c *i2c = dev_id;
 425         unsigned long status;
 426         unsigned long tmp;
 427
 428         status = readl(i2c->regs + S3C2410_IICSTAT);
 429
 430         if (status & S3C2410_IICSTAT_ARBITR) {
 431                 /* deal with arbitration loss */
 432                 dev_err(i2c->dev, "deal with arbitration loss\n");
 433         }
 434
 435         if (i2c->state == STATE_IDLE) {
 436                 dev_dbg(i2c->dev, "IRQ: error i2c->state == IDLE\n");
 437
 438                 tmp = readl(i2c->regs + S3C2410_IICCON);
 439                 tmp &= ~S3C2410_IICCON_IRQPEND;
 440                 writel(tmp, i2c->regs +  S3C2410_IICCON);
 441                 goto out;
 442         }
 443
 444         /* pretty much this leaves us with the fact that we've
 445          * transmitted or received whatever byte we last sent */
 446
 447         i2s_s3c_irq_nextbyte(i2c, status);
 448
 449  out:
 450         return IRQ_HANDLED;
 451 }
 452
 453
 454 /* s3c24xx_i2c_set_master
 455  *
 456  * get the i2c bus for a master transaction
 457 */
 458
 459 static int s3c24xx_i2c_set_master(struct s3c24xx_i2c *i2c)
 460 {
 461         unsigned long iicstat;
 462         int timeout = 400;
 463
 464         while (timeout-- > 0) {
 465                 iicstat = readl(i2c->regs + S3C2410_IICSTAT);
 466
 467                 if (!(iicstat & S3C2410_IICSTAT_BUSBUSY))
 468                         return 0;
 469
 470                 msleep(1);
 471         }
 472
 473         return -ETIMEDOUT;
 474 }
 475
 476 /* s3c24xx_i2c_doxfer
 477  *
 478  * this starts an i2c transfer
 479 */
 480
 481 static int s3c24xx_i2c_doxfer(struct s3c24xx_i2c *i2c,
 482                               struct i2c_msg *msgs, int num)
 483 {
 484         unsigned long iicstat, timeout;
 485         int spins = 20;
 486         int ret;
 487
 488         if (i2c->suspended)
 489                 return -EIO;
 490
 491         ret = s3c24xx_i2c_set_master(i2c);
 492         if (ret != 0) {
 493                 dev_err(i2c->dev, "cannot get bus (error %d)\n", ret);
 494                 ret = -EAGAIN;
 495                 goto out;
 496         }
 497
 498         spin_lock_irq(&i2c->lock);
 499
 500         i2c->msg     = msgs;
 501         i2c->msg_num = num;
 502         i2c->msg_ptr = 0;
 503         i2c->msg_idx = 0;
 504         i2c->state   = STATE_START;
 505
 506         s3c24xx_i2c_enable_irq(i2c);
 507         s3c24xx_i2c_message_start(i2c, msgs);
 508         spin_unlock_irq(&i2c->lock);
 509
 510         timeout = wait_event_timeout(i2c->wait, i2c->msg_num == 0, HZ * 5);
 511
 512         ret = i2c->msg_idx;
 513
 514         /* having these next two as dev_err() makes life very
 515          * noisy when doing an i2cdetect */
 516
 517         if (timeout == 0)
 518                 dev_dbg(i2c->dev, "timeout\n");
 519         else if (ret != num)
 520                 dev_dbg(i2c->dev, "incomplete xfer (%d)\n", ret);
 521
 522         /* ensure the stop has been through the bus */
 523
 524         dev_dbg(i2c->dev, "waiting for bus idle\n");
 525
 526         /* first, try busy waiting briefly */
 527         do {
 528                 iicstat = readl(i2c->regs + S3C2410_IICSTAT);
 529         } while ((iicstat & S3C2410_IICSTAT_START) && --spins);
 530
 531         /* if that timed out sleep */
 532         if (!spins) {
 533                 msleep(1);
 534                 iicstat = readl(i2c->regs + S3C2410_IICSTAT);
 535         }
 536
 537         if (iicstat & S3C2410_IICSTAT_START)
 538                 dev_warn(i2c->dev, "timeout waiting for bus idle\n");
 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         clk_enable(i2c->clk);
 558
 559         for (retry = 0; retry < adap->retries; retry++) {
 560
 561                 ret = s3c24xx_i2c_doxfer(i2c, msgs, num);
 562
 563                 if (ret != -EAGAIN) {
 564                         clk_disable(i2c->clk);
 565                         return ret;
 566                 }
 567
 568                 dev_dbg(i2c->dev, "Retrying transmission (%d)\n", retry);
 569
 570                 udelay(100);
 571         }
 572
 573         clk_disable(i2c->clk);
 574         return -EREMOTEIO;
 575 }
 576
 577 /* declare our i2c functionality */
 578 static u32 s3c24xx_i2c_func(struct i2c_adapter *adap)
 579 {
 580         return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_PROTOCOL_MANGLING;
 581 }
 582
 583 /* i2c bus registration info */
 584
 585 static const struct i2c_algorithm s3c24xx_i2c_algorithm = {
 586         .master_xfer            = s3c24xx_i2c_xfer,
 587         .functionality          = s3c24xx_i2c_func,
 588 };
 589
 590 /* s3c24xx_i2c_calcdivisor
 591  *
 592  * return the divisor settings for a given frequency
 593 */
 594
 595 static int s3c24xx_i2c_calcdivisor(unsigned long clkin, unsigned int wanted,
 596                                    unsigned int *div1, unsigned int *divs)
 597 {
 598         unsigned int calc_divs = clkin / wanted;
 599         unsigned int calc_div1;
 600
 601         if (calc_divs > (16*16))
 602                 calc_div1 = 512;
 603         else
 604                 calc_div1 = 16;
 605
 606         calc_divs += calc_div1-1;
 607         calc_divs /= calc_div1;
 608
 609         if (calc_divs == 0)
 610                 calc_divs = 1;
 611         if (calc_divs > 17)
 612                 calc_divs = 17;
 613
 614         *divs = calc_divs;
 615         *div1 = calc_div1;
 616
 617         return clkin / (calc_divs * calc_div1);
 618 }
 619
 620 /* s3c24xx_i2c_clockrate
 621  *
 622  * work out a divisor for the user requested frequency setting,
 623  * either by the requested frequency, or scanning the acceptable
 624  * range of frequencies until something is found
 625 */
 626
 627 static int s3c24xx_i2c_clockrate(struct s3c24xx_i2c *i2c, unsigned int *got)
 628 {
 629         struct s3c2410_platform_i2c *pdata = i2c->dev->platform_data;
 630         unsigned long clkin = clk_get_rate(i2c->clk);
 631         unsigned int divs, div1;
 632         unsigned long target_frequency;
 633         u32 iiccon;
 634         int freq;
 635
 636         i2c->clkrate = clkin;
 637         clkin /= 1000;          /* clkin now in KHz */
 638
 639         dev_dbg(i2c->dev, "pdata desired frequency %lu\n", pdata->frequency);
 640
 641         target_frequency = pdata->frequency ? pdata->frequency : 100000;
 642
 643         target_frequency /= 1000; /* Target frequency now in KHz */
 644
 645         freq = s3c24xx_i2c_calcdivisor(clkin, target_frequency, &div1, &divs);
 646
 647         if (freq > target_frequency) {
 648                 dev_err(i2c->dev,
 649                         "Unable to achieve desired frequency %luKHz."   \
 650                         " Lowest achievable %dKHz\n", target_frequency, freq);
 651                 return -EINVAL;
 652         }
 653
 654         *got = freq;
 655
 656         iiccon = readl(i2c->regs + S3C2410_IICCON);
 657         iiccon &= ~(S3C2410_IICCON_SCALEMASK | S3C2410_IICCON_TXDIV_512);
 658         iiccon |= (divs-1);
 659
 660         if (div1 == 512)
 661                 iiccon |= S3C2410_IICCON_TXDIV_512;
 662
 663         writel(iiccon, i2c->regs + S3C2410_IICCON);
 664
 665         if (s3c24xx_i2c_is2440(i2c)) {
 666                 unsigned long sda_delay;
 667
 668                 if (pdata->sda_delay) {
 669                         sda_delay = clkin * pdata->sda_delay;
 670                         sda_delay = DIV_ROUND_UP(sda_delay, 1000000);
 671                         sda_delay = DIV_ROUND_UP(sda_delay, 5);
 672                         if (sda_delay > 3)
 673                                 sda_delay = 3;
 674                         sda_delay |= S3C2410_IICLC_FILTER_ON;
 675                 } else
 676                         sda_delay = 0;
 677
 678                 dev_dbg(i2c->dev, "IICLC=%08lx\n", sda_delay);
 679                 writel(sda_delay, i2c->regs + S3C2440_IICLC);
 680         }
 681
 682         return 0;
 683 }
 684
 685 #ifdef CONFIG_CPU_FREQ
 686
 687 #define freq_to_i2c(_n) container_of(_n, struct s3c24xx_i2c, freq_transition)
 688
 689 static int s3c24xx_i2c_cpufreq_transition(struct notifier_block *nb,
 690                                           unsigned long val, void *data)
 691 {
 692         struct s3c24xx_i2c *i2c = freq_to_i2c(nb);
 693         unsigned long flags;
 694         unsigned int got;
 695         int delta_f;
 696         int ret;
 697
 698         delta_f = clk_get_rate(i2c->clk) - i2c->clkrate;
 699
 700         /* if we're post-change and the input clock has slowed down
 701          * or at pre-change and the clock is about to speed up, then
 702          * adjust our clock rate. <0 is slow, >0 speedup.
 703          */
 704
 705         if ((val == CPUFREQ_POSTCHANGE && delta_f < 0) ||
 706             (val == CPUFREQ_PRECHANGE && delta_f > 0)) {
 707                 spin_lock_irqsave(&i2c->lock, flags);
 708                 ret = s3c24xx_i2c_clockrate(i2c, &got);
 709                 spin_unlock_irqrestore(&i2c->lock, flags);
 710
 711                 if (ret < 0)
 712                         dev_err(i2c->dev, "cannot find frequency\n");
 713                 else
 714                         dev_info(i2c->dev, "setting freq %d\n", got);
 715         }
 716
 717         return 0;
 718 }
 719
 720 static inline int s3c24xx_i2c_register_cpufreq(struct s3c24xx_i2c *i2c)
 721 {
 722         i2c->freq_transition.notifier_call = s3c24xx_i2c_cpufreq_transition;
 723
 724         return cpufreq_register_notifier(&i2c->freq_transition,
 725                                          CPUFREQ_TRANSITION_NOTIFIER);
 726 }
 727
 728 static inline void s3c24xx_i2c_deregister_cpufreq(struct s3c24xx_i2c *i2c)
 729 {
 730         cpufreq_unregister_notifier(&i2c->freq_transition,
 731                                     CPUFREQ_TRANSITION_NOTIFIER);
 732 }
 733
 734 #else
 735 static inline int s3c24xx_i2c_register_cpufreq(struct s3c24xx_i2c *i2c)
 736 {
 737         return 0;
 738 }
 739
 740 static inline void s3c24xx_i2c_deregister_cpufreq(struct s3c24xx_i2c *i2c)
 741 {
 742 }
 743 #endif
 744
 745 /* s3c24xx_i2c_init
 746  *
 747  * initialise the controller, set the IO lines and frequency
 748 */
 749
 750 static int s3c24xx_i2c_init(struct s3c24xx_i2c *i2c)
 751 {
 752         unsigned long iicon = S3C2410_IICCON_IRQEN | S3C2410_IICCON_ACKEN;
 753         struct s3c2410_platform_i2c *pdata;
 754         unsigned int freq;
 755
 756         /* get the plafrom data */
 757
 758         pdata = i2c->dev->platform_data;
 759
 760         /* inititalise the gpio */
 761
 762         if (pdata->cfg_gpio)
 763                 pdata->cfg_gpio(to_platform_device(i2c->dev));
 764
 765         /* write slave address */
 766
 767         writeb(pdata->slave_addr, i2c->regs + S3C2410_IICADD);
 768
 769         dev_info(i2c->dev, "slave address 0x%02x\n", pdata->slave_addr);
 770
 771         writel(iicon, i2c->regs + S3C2410_IICCON);
 772
 773         /* we need to work out the divisors for the clock... */
 774
 775         if (s3c24xx_i2c_clockrate(i2c, &freq) != 0) {
 776                 writel(0, i2c->regs + S3C2410_IICCON);
 777                 dev_err(i2c->dev, "cannot meet bus frequency required\n");
 778                 return -EINVAL;
 779         }
 780
 781         /* todo - check that the i2c lines aren't being dragged anywhere */
 782
 783         dev_info(i2c->dev, "bus frequency set to %d KHz\n", freq);
 784         dev_dbg(i2c->dev, "S3C2410_IICCON=0x%02lx\n", iicon);
 785
 786         return 0;
 787 }
 788
 789 /* s3c24xx_i2c_probe
 790  *
 791  * called by the bus driver when a suitable device is found
 792 */
 793
 794 static int s3c24xx_i2c_probe(struct platform_device *pdev)
 795 {
 796         struct s3c24xx_i2c *i2c;
 797         struct s3c2410_platform_i2c *pdata;
 798         struct resource *res;
 799         int ret;
 800
 801         pdata = pdev->dev.platform_data;
 802         if (!pdata) {
 803                 dev_err(&pdev->dev, "no platform data\n");
 804                 return -EINVAL;
 805         }
 806
 807         i2c = kzalloc(sizeof(struct s3c24xx_i2c), GFP_KERNEL);
 808         if (!i2c) {
 809                 dev_err(&pdev->dev, "no memory for state\n");
 810                 return -ENOMEM;
 811         }
 812
 813         strlcpy(i2c->adap.name, "s3c2410-i2c", sizeof(i2c->adap.name));
 814         i2c->adap.owner   = THIS_MODULE;
 815         i2c->adap.algo    = &s3c24xx_i2c_algorithm;
 816         i2c->adap.retries = 2;
 817         i2c->adap.class   = I2C_CLASS_HWMON | I2C_CLASS_SPD;
 818         i2c->tx_setup     = 50;
 819
 820         spin_lock_init(&i2c->lock);
 821         init_waitqueue_head(&i2c->wait);
 822
 823         /* find the clock and enable it */
 824
 825         i2c->dev = &pdev->dev;
 826         i2c->clk = clk_get(&pdev->dev, "i2c");
 827         if (IS_ERR(i2c->clk)) {
 828                 dev_err(&pdev->dev, "cannot get clock\n");
 829                 ret = -ENOENT;
 830                 goto err_noclk;
 831         }
 832
 833         dev_dbg(&pdev->dev, "clock source %p\n", i2c->clk);
 834
 835         clk_enable(i2c->clk);
 836
 837         /* map the registers */
 838
 839         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 840         if (res == NULL) {
 841                 dev_err(&pdev->dev, "cannot find IO resource\n");
 842                 ret = -ENOENT;
 843                 goto err_clk;
 844         }
 845
 846         i2c->ioarea = request_mem_region(res->start, resource_size(res),
 847                                          pdev->name);
 848
 849         if (i2c->ioarea == NULL) {
 850                 dev_err(&pdev->dev, "cannot request IO\n");
 851                 ret = -ENXIO;
 852                 goto err_clk;
 853         }
 854
 855         i2c->regs = ioremap(res->start, resource_size(res));
 856
 857         if (i2c->regs == NULL) {
 858                 dev_err(&pdev->dev, "cannot map IO\n");
 859                 ret = -ENXIO;
 860                 goto err_ioarea;
 861         }
 862
 863         dev_dbg(&pdev->dev, "registers %p (%p, %p)\n",
 864                 i2c->regs, i2c->ioarea, res);
 865
 866         /* setup info block for the i2c core */
 867
 868         i2c->adap.algo_data = i2c;
 869         i2c->adap.dev.parent = &pdev->dev;
 870
 871         /* initialise the i2c controller */
 872
 873         ret = s3c24xx_i2c_init(i2c);
 874         if (ret != 0)
 875                 goto err_iomap;
 876
 877         /* find the IRQ for this unit (note, this relies on the init call to
 878          * ensure no current IRQs pending
 879          */
 880
 881         i2c->irq = ret = platform_get_irq(pdev, 0);
 882         if (ret <= 0) {
 883                 dev_err(&pdev->dev, "cannot find IRQ\n");
 884                 goto err_iomap;
 885         }
 886
 887         ret = request_irq(i2c->irq, s3c24xx_i2c_irq, IRQF_DISABLED,
 888                           dev_name(&pdev->dev), i2c);
 889
 890         if (ret != 0) {
 891                 dev_err(&pdev->dev, "cannot claim IRQ %d\n", i2c->irq);
 892                 goto err_iomap;
 893         }
 894
 895         ret = s3c24xx_i2c_register_cpufreq(i2c);
 896         if (ret < 0) {
 897                 dev_err(&pdev->dev, "failed to register cpufreq notifier\n");
 898                 goto err_irq;
 899         }
 900
 901         /* Note, previous versions of the driver used i2c_add_adapter()
 902          * to add the bus at any number. We now pass the bus number via
 903          * the platform data, so if unset it will now default to always
 904          * being bus 0.
 905          */
 906
 907         i2c->adap.nr = pdata->bus_num;
 908
 909         ret = i2c_add_numbered_adapter(&i2c->adap);
 910         if (ret < 0) {
 911                 dev_err(&pdev->dev, "failed to add bus to i2c core\n");
 912                 goto err_cpufreq;
 913         }
 914
 915         platform_set_drvdata(pdev, i2c);
 916
 917         dev_info(&pdev->dev, "%s: S3C I2C adapter\n", dev_name(&i2c->adap.dev));
 918         clk_disable(i2c->clk);
 919         return 0;
 920
 921  err_cpufreq:
 922         s3c24xx_i2c_deregister_cpufreq(i2c);
 923
 924  err_irq:
 925         free_irq(i2c->irq, i2c);
 926
 927  err_iomap:
 928         iounmap(i2c->regs);
 929
 930  err_ioarea:
 931         release_resource(i2c->ioarea);
 932         kfree(i2c->ioarea);
 933
 934  err_clk:
 935         clk_disable(i2c->clk);
 936         clk_put(i2c->clk);
 937
 938  err_noclk:
 939         kfree(i2c);
 940         return ret;
 941 }
 942
 943 /* s3c24xx_i2c_remove
 944  *
 945  * called when device is removed from the bus
 946 */
 947
 948 static int s3c24xx_i2c_remove(struct platform_device *pdev)
 949 {
 950         struct s3c24xx_i2c *i2c = platform_get_drvdata(pdev);
 951
 952         s3c24xx_i2c_deregister_cpufreq(i2c);
 953
 954         i2c_del_adapter(&i2c->adap);
 955         free_irq(i2c->irq, i2c);
 956
 957         clk_disable(i2c->clk);
 958         clk_put(i2c->clk);
 959
 960         iounmap(i2c->regs);
 961
 962         release_resource(i2c->ioarea);
 963         kfree(i2c->ioarea);
 964         kfree(i2c);
 965
 966         return 0;
 967 }
 968
 969 #ifdef CONFIG_PM
 970 static int s3c24xx_i2c_suspend_noirq(struct device *dev)
 971 {
 972         struct platform_device *pdev = to_platform_device(dev);
 973         struct s3c24xx_i2c *i2c = platform_get_drvdata(pdev);
 974
 975         i2c->suspended = 1;
 976
 977         return 0;
 978 }
 979
 980 static int s3c24xx_i2c_resume(struct device *dev)
 981 {
 982         struct platform_device *pdev = to_platform_device(dev);
 983         struct s3c24xx_i2c *i2c = platform_get_drvdata(pdev);
 984
 985         i2c->suspended = 0;
 986         clk_enable(i2c->clk);
 987         s3c24xx_i2c_init(i2c);
 988         clk_disable(i2c->clk);
 989
 990         return 0;
 991 }
 992
 993 static const struct dev_pm_ops s3c24xx_i2c_dev_pm_ops = {
 994         .suspend_noirq = s3c24xx_i2c_suspend_noirq,
 995         .resume = s3c24xx_i2c_resume,
 996 };
 997
 998 #define S3C24XX_DEV_PM_OPS (&s3c24xx_i2c_dev_pm_ops)
 999 #else
1000 #define S3C24XX_DEV_PM_OPS NULL
1001 #endif
1002
1003 /* device driver for platform bus bits */
1004
1005 static struct platform_device_id s3c24xx_driver_ids[] = {
1006         {
1007                 .name           = "s3c2410-i2c",
1008                 .driver_data    = TYPE_S3C2410,
1009         }, {
1010                 .name           = "s3c2440-i2c",
1011                 .driver_data    = TYPE_S3C2440,
1012         }, { },
1013 };
1014 MODULE_DEVICE_TABLE(platform, s3c24xx_driver_ids);
1015
1016 static struct platform_driver s3c24xx_i2c_driver = {
1017         .probe          = s3c24xx_i2c_probe,
1018         .remove         = s3c24xx_i2c_remove,
1019         .id_table       = s3c24xx_driver_ids,
1020         .driver         = {
1021                 .owner  = THIS_MODULE,
1022                 .name   = "s3c-i2c",
1023                 .pm     = S3C24XX_DEV_PM_OPS,
1024         },
1025 };
1026
1027 static int __init i2c_adap_s3c_init(void)
1028 {
1029         return platform_driver_register(&s3c24xx_i2c_driver);
1030 }
1031 subsys_initcall(i2c_adap_s3c_init);
1032
1033 static void __exit i2c_adap_s3c_exit(void)
1034 {
1035         platform_driver_unregister(&s3c24xx_i2c_driver);
1036 }
1037 module_exit(i2c_adap_s3c_exit);
1038
1039 MODULE_DESCRIPTION("S3C24XX I2C Bus driver");
1040 MODULE_AUTHOR("Ben Dooks, <ben@simtec.co.uk>");
1041 MODULE_LICENSE("GPL");