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/arch/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", __func__);
 280                 goto out;
 281                 break;
 282
 283         case STATE_STOP:
 284                 dev_err(i2c->dev, "%s: called in STATE_STOP\n", __func__);
 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, -ENXIO);
 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                  * as this is 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                 if (!(i2c->msg->flags & I2C_M_IGNORE_NAK)) {
 327                         if (iicstat & S3C2410_IICSTAT_LASTBIT) {
 328                                 dev_dbg(i2c->dev, "WRITE: No Ack\n");
 329
 330                                 s3c24xx_i2c_stop(i2c, -ECONNREFUSED);
 331                                 goto out_ack;
 332                         }
 333                 }
 334
 335         retry_write:
 336
 337                 if (!is_msgend(i2c)) {
 338                         byte = i2c->msg->buf[i2c->msg_ptr++];
 339                         writeb(byte, i2c->regs + S3C2410_IICDS);
 340
 341                         /* delay after writing the byte to allow the
 342                          * data setup time on the bus, as writing the
 343                          * data to the register causes the first bit
 344                          * to appear on SDA, and SCL will change as
 345                          * soon as the interrupt is acknowledged */
 346
 347                         ndelay(i2c->tx_setup);
 348
 349                 } else if (!is_lastmsg(i2c)) {
 350                         /* we need to go to the next i2c message */
 351
 352                         dev_dbg(i2c->dev, "WRITE: Next Message\n");
 353
 354                         i2c->msg_ptr = 0;
 355                         i2c->msg_idx ++;
 356                         i2c->msg++;
 357
 358                         /* check to see if we need to do another message */
 359                         if (i2c->msg->flags & I2C_M_NOSTART) {
 360
 361                                 if (i2c->msg->flags & I2C_M_RD) {
 362                                         /* cannot do this, the controller
 363                                          * forces us to send a new START
 364                                          * when we change direction */
 365
 366                                         s3c24xx_i2c_stop(i2c, -EINVAL);
 367                                 }
 368
 369                                 goto retry_write;
 370                         } else {
 371
 372                                 /* send the new start */
 373                                 s3c24xx_i2c_message_start(i2c, i2c->msg);
 374                                 i2c->state = STATE_START;
 375                         }
 376
 377                 } else {
 378                         /* send stop */
 379
 380                         s3c24xx_i2c_stop(i2c, 0);
 381                 }
 382                 break;
 383
 384         case STATE_READ:
 385                 /* we have a byte of data in the data register, do
 386                  * something with it, and then work out wether we are
 387                  * going to do any more read/write
 388                  */
 389
 390                 byte = readb(i2c->regs + S3C2410_IICDS);
 391                 i2c->msg->buf[i2c->msg_ptr++] = byte;
 392
 393         prepare_read:
 394                 if (is_msglast(i2c)) {
 395                         /* last byte of buffer */
 396
 397                         if (is_lastmsg(i2c))
 398                                 s3c24xx_i2c_disable_ack(i2c);
 399
 400                 } else if (is_msgend(i2c)) {
 401                         /* ok, we've read the entire buffer, see if there
 402                          * is anything else we need to do */
 403
 404                         if (is_lastmsg(i2c)) {
 405                                 /* last message, send stop and complete */
 406                                 dev_dbg(i2c->dev, "READ: Send Stop\n");
 407
 408                                 s3c24xx_i2c_stop(i2c, 0);
 409                         } else {
 410                                 /* go to the next transfer */
 411                                 dev_dbg(i2c->dev, "READ: Next Transfer\n");
 412
 413                                 i2c->msg_ptr = 0;
 414                                 i2c->msg_idx++;
 415                                 i2c->msg++;
 416                         }
 417                 }
 418
 419                 break;
 420         }
 421
 422         /* acknowlegde the IRQ and get back on with the work */
 423
 424  out_ack:
 425         tmp = readl(i2c->regs + S3C2410_IICCON);
 426         tmp &= ~S3C2410_IICCON_IRQPEND;
 427         writel(tmp, i2c->regs + S3C2410_IICCON);
 428  out:
 429         return ret;
 430 }
 431
 432 /* s3c24xx_i2c_irq
 433  *
 434  * top level IRQ servicing routine
 435 */
 436
 437 static irqreturn_t s3c24xx_i2c_irq(int irqno, void *dev_id)
 438 {
 439         struct s3c24xx_i2c *i2c = dev_id;
 440         unsigned long status;
 441         unsigned long tmp;
 442
 443         status = readl(i2c->regs + S3C2410_IICSTAT);
 444
 445         if (status & S3C2410_IICSTAT_ARBITR) {
 446                 // deal with arbitration loss
 447                 dev_err(i2c->dev, "deal with arbitration loss\n");
 448         }
 449
 450         if (i2c->state == STATE_IDLE) {
 451                 dev_dbg(i2c->dev, "IRQ: error i2c->state == IDLE\n");
 452
 453                 tmp = readl(i2c->regs + S3C2410_IICCON);
 454                 tmp &= ~S3C2410_IICCON_IRQPEND;
 455                 writel(tmp, i2c->regs +  S3C2410_IICCON);
 456                 goto out;
 457         }
 458
 459         /* pretty much this leaves us with the fact that we've
 460          * transmitted or received whatever byte we last sent */
 461
 462         i2s_s3c_irq_nextbyte(i2c, status);
 463
 464  out:
 465         return IRQ_HANDLED;
 466 }
 467
 468
 469 /* s3c24xx_i2c_set_master
 470  *
 471  * get the i2c bus for a master transaction
 472 */
 473
 474 static int s3c24xx_i2c_set_master(struct s3c24xx_i2c *i2c)
 475 {
 476         unsigned long iicstat;
 477         int timeout = 400;
 478
 479         while (timeout-- > 0) {
 480                 iicstat = readl(i2c->regs + S3C2410_IICSTAT);
 481
 482                 if (!(iicstat & S3C2410_IICSTAT_BUSBUSY))
 483                         return 0;
 484
 485                 msleep(1);
 486         }
 487
 488         dev_dbg(i2c->dev, "timeout: GPEDAT is %08x\n",
 489                 __raw_readl(S3C2410_GPEDAT));
 490
 491         return -ETIMEDOUT;
 492 }
 493
 494 /* s3c24xx_i2c_doxfer
 495  *
 496  * this starts an i2c transfer
 497 */
 498
 499 static int s3c24xx_i2c_doxfer(struct s3c24xx_i2c *i2c, struct i2c_msg *msgs, int num)
 500 {
 501         unsigned long timeout;
 502         int ret;
 503
 504         ret = s3c24xx_i2c_set_master(i2c);
 505         if (ret != 0) {
 506                 dev_err(i2c->dev, "cannot get bus (error %d)\n", ret);
 507                 ret = -EAGAIN;
 508                 goto out;
 509         }
 510
 511         spin_lock_irq(&i2c->lock);
 512
 513         i2c->msg     = msgs;
 514         i2c->msg_num = num;
 515         i2c->msg_ptr = 0;
 516         i2c->msg_idx = 0;
 517         i2c->state   = STATE_START;
 518
 519         s3c24xx_i2c_enable_irq(i2c);
 520         s3c24xx_i2c_message_start(i2c, msgs);
 521         spin_unlock_irq(&i2c->lock);
 522
 523         timeout = wait_event_timeout(i2c->wait, i2c->msg_num == 0, HZ * 5);
 524
 525         ret = i2c->msg_idx;
 526
 527         /* having these next two as dev_err() makes life very
 528          * noisy when doing an i2cdetect */
 529
 530         if (timeout == 0)
 531                 dev_dbg(i2c->dev, "timeout\n");
 532         else if (ret != num)
 533                 dev_dbg(i2c->dev, "incomplete xfer (%d)\n", ret);
 534
 535         /* ensure the stop has been through the bus */
 536
 537         msleep(1);
 538
 539  out:
 540         return ret;
 541 }
 542
 543 /* s3c24xx_i2c_xfer
 544  *
 545  * first port of call from the i2c bus code when an message needs
 546  * transferring across the i2c bus.
 547 */
 548
 549 static int s3c24xx_i2c_xfer(struct i2c_adapter *adap,
 550                         struct i2c_msg *msgs, int num)
 551 {
 552         struct s3c24xx_i2c *i2c = (struct s3c24xx_i2c *)adap->algo_data;
 553         int retry;
 554         int ret;
 555
 556         for (retry = 0; retry < adap->retries; retry++) {
 557
 558                 ret = s3c24xx_i2c_doxfer(i2c, msgs, num);
 559
 560                 if (ret != -EAGAIN)
 561                         return ret;
 562
 563                 dev_dbg(i2c->dev, "Retrying transmission (%d)\n", retry);
 564
 565                 udelay(100);
 566         }
 567
 568         return -EREMOTEIO;
 569 }
 570
 571 /* declare our i2c functionality */
 572 static u32 s3c24xx_i2c_func(struct i2c_adapter *adap)
 573 {
 574         return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_PROTOCOL_MANGLING;
 575 }
 576
 577 /* i2c bus registration info */
 578
 579 static const struct i2c_algorithm s3c24xx_i2c_algorithm = {
 580         .master_xfer            = s3c24xx_i2c_xfer,
 581         .functionality          = s3c24xx_i2c_func,
 582 };
 583
 584 static struct s3c24xx_i2c s3c24xx_i2c = {
 585         .lock           = __SPIN_LOCK_UNLOCKED(s3c24xx_i2c.lock),
 586         .wait           = __WAIT_QUEUE_HEAD_INITIALIZER(s3c24xx_i2c.wait),
 587         .tx_setup       = 50,
 588         .adap           = {
 589                 .name                   = "s3c2410-i2c",
 590                 .owner                  = THIS_MODULE,
 591                 .algo                   = &s3c24xx_i2c_algorithm,
 592                 .retries                = 2,
 593                 .class                  = I2C_CLASS_HWMON | I2C_CLASS_SPD,
 594         },
 595 };
 596
 597 /* s3c24xx_i2c_calcdivisor
 598  *
 599  * return the divisor settings for a given frequency
 600 */
 601
 602 static int s3c24xx_i2c_calcdivisor(unsigned long clkin, unsigned int wanted,
 603                                    unsigned int *div1, unsigned int *divs)
 604 {
 605         unsigned int calc_divs = clkin / wanted;
 606         unsigned int calc_div1;
 607
 608         if (calc_divs > (16*16))
 609                 calc_div1 = 512;
 610         else
 611                 calc_div1 = 16;
 612
 613         calc_divs += calc_div1-1;
 614         calc_divs /= calc_div1;
 615
 616         if (calc_divs == 0)
 617                 calc_divs = 1;
 618         if (calc_divs > 17)
 619                 calc_divs = 17;
 620
 621         *divs = calc_divs;
 622         *div1 = calc_div1;
 623
 624         return clkin / (calc_divs * calc_div1);
 625 }
 626
 627 /* freq_acceptable
 628  *
 629  * test wether a frequency is within the acceptable range of error
 630 */
 631
 632 static inline int freq_acceptable(unsigned int freq, unsigned int wanted)
 633 {
 634         int diff = freq - wanted;
 635
 636         return (diff >= -2 && diff <= 2);
 637 }
 638
 639 /* s3c24xx_i2c_getdivisor
 640  *
 641  * work out a divisor for the user requested frequency setting,
 642  * either by the requested frequency, or scanning the acceptable
 643  * range of frequencies until something is found
 644 */
 645
 646 static int s3c24xx_i2c_getdivisor(struct s3c24xx_i2c *i2c,
 647                                   struct s3c2410_platform_i2c *pdata,
 648                                   unsigned long *iicon,
 649                                   unsigned int *got)
 650 {
 651         unsigned long clkin = clk_get_rate(i2c->clk);
 652
 653         unsigned int divs, div1;
 654         int freq;
 655         int start, end;
 656
 657         clkin /= 1000;          /* clkin now in KHz */
 658
 659         dev_dbg(i2c->dev,  "pdata %p, freq %lu %lu..%lu\n",
 660                  pdata, pdata->bus_freq, pdata->min_freq, pdata->max_freq);
 661
 662         if (pdata->bus_freq != 0) {
 663                 freq = s3c24xx_i2c_calcdivisor(clkin, pdata->bus_freq/1000,
 664                                                &div1, &divs);
 665                 if (freq_acceptable(freq, pdata->bus_freq/1000))
 666                         goto found;
 667         }
 668
 669         /* ok, we may have to search for something suitable... */
 670
 671         start = (pdata->max_freq == 0) ? pdata->bus_freq : pdata->max_freq;
 672         end = pdata->min_freq;
 673
 674         start /= 1000;
 675         end /= 1000;
 676
 677         /* search loop... */
 678
 679         for (; start > end; start--) {
 680                 freq = s3c24xx_i2c_calcdivisor(clkin, start, &div1, &divs);
 681                 if (freq_acceptable(freq, start))
 682                         goto found;
 683         }
 684
 685         /* cannot find frequency spec */
 686
 687         return -EINVAL;
 688
 689  found:
 690         *got = freq;
 691         *iicon |= (divs-1);
 692         *iicon |= (div1 == 512) ? S3C2410_IICCON_TXDIV_512 : 0;
 693         return 0;
 694 }
 695
 696 /* s3c24xx_i2c_init
 697  *
 698  * initialise the controller, set the IO lines and frequency
 699 */
 700
 701 static int s3c24xx_i2c_init(struct s3c24xx_i2c *i2c)
 702 {
 703         unsigned long iicon = S3C2410_IICCON_IRQEN | S3C2410_IICCON_ACKEN;
 704         struct s3c2410_platform_i2c *pdata;
 705         unsigned int freq;
 706
 707         /* get the plafrom data */
 708
 709         pdata = s3c24xx_i2c_get_platformdata(i2c->adap.dev.parent);
 710
 711         /* inititalise the gpio */
 712
 713         s3c2410_gpio_cfgpin(S3C2410_GPE15, S3C2410_GPE15_IICSDA);
 714         s3c2410_gpio_cfgpin(S3C2410_GPE14, S3C2410_GPE14_IICSCL);
 715
 716         /* write slave address */
 717
 718         writeb(pdata->slave_addr, i2c->regs + S3C2410_IICADD);
 719
 720         dev_info(i2c->dev, "slave address 0x%02x\n", pdata->slave_addr);
 721
 722         /* we need to work out the divisors for the clock... */
 723
 724         if (s3c24xx_i2c_getdivisor(i2c, pdata, &iicon, &freq) != 0) {
 725                 dev_err(i2c->dev, "cannot meet bus frequency required\n");
 726                 return -EINVAL;
 727         }
 728
 729         /* todo - check that the i2c lines aren't being dragged anywhere */
 730
 731         dev_info(i2c->dev, "bus frequency set to %d KHz\n", freq);
 732         dev_dbg(i2c->dev, "S3C2410_IICCON=0x%02lx\n", iicon);
 733
 734         writel(iicon, i2c->regs + S3C2410_IICCON);
 735
 736         /* check for s3c2440 i2c controller  */
 737
 738         if (s3c24xx_i2c_is2440(i2c)) {
 739                 dev_dbg(i2c->dev, "S3C2440_IICLC=%08x\n", pdata->sda_delay);
 740
 741                 writel(pdata->sda_delay, i2c->regs + S3C2440_IICLC);
 742         }
 743
 744         return 0;
 745 }
 746
 747 /* s3c24xx_i2c_probe
 748  *
 749  * called by the bus driver when a suitable device is found
 750 */
 751
 752 static int s3c24xx_i2c_probe(struct platform_device *pdev)
 753 {
 754         struct s3c24xx_i2c *i2c = &s3c24xx_i2c;
 755         struct resource *res;
 756         int ret;
 757
 758         /* find the clock and enable it */
 759
 760         i2c->dev = &pdev->dev;
 761         i2c->clk = clk_get(&pdev->dev, "i2c");
 762         if (IS_ERR(i2c->clk)) {
 763                 dev_err(&pdev->dev, "cannot get clock\n");
 764                 ret = -ENOENT;
 765                 goto err_noclk;
 766         }
 767
 768         dev_dbg(&pdev->dev, "clock source %p\n", i2c->clk);
 769
 770         clk_enable(i2c->clk);
 771
 772         /* map the registers */
 773
 774         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 775         if (res == NULL) {
 776                 dev_err(&pdev->dev, "cannot find IO resource\n");
 777                 ret = -ENOENT;
 778                 goto err_clk;
 779         }
 780
 781         i2c->ioarea = request_mem_region(res->start, (res->end-res->start)+1,
 782                                          pdev->name);
 783
 784         if (i2c->ioarea == NULL) {
 785                 dev_err(&pdev->dev, "cannot request IO\n");
 786                 ret = -ENXIO;
 787                 goto err_clk;
 788         }
 789
 790         i2c->regs = ioremap(res->start, (res->end-res->start)+1);
 791
 792         if (i2c->regs == NULL) {
 793                 dev_err(&pdev->dev, "cannot map IO\n");
 794                 ret = -ENXIO;
 795                 goto err_ioarea;
 796         }
 797
 798         dev_dbg(&pdev->dev, "registers %p (%p, %p)\n", i2c->regs, i2c->ioarea, res);
 799
 800         /* setup info block for the i2c core */
 801
 802         i2c->adap.algo_data = i2c;
 803         i2c->adap.dev.parent = &pdev->dev;
 804
 805         /* initialise the i2c controller */
 806
 807         ret = s3c24xx_i2c_init(i2c);
 808         if (ret != 0)
 809                 goto err_iomap;
 810
 811         /* find the IRQ for this unit (note, this relies on the init call to
 812          * ensure no current IRQs pending
 813          */
 814
 815         res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
 816         if (res == NULL) {
 817                 dev_err(&pdev->dev, "cannot find IRQ\n");
 818                 ret = -ENOENT;
 819                 goto err_iomap;
 820         }
 821
 822         ret = request_irq(res->start, s3c24xx_i2c_irq, IRQF_DISABLED,
 823                           pdev->name, i2c);
 824
 825         if (ret != 0) {
 826                 dev_err(&pdev->dev, "cannot claim IRQ\n");
 827                 goto err_iomap;
 828         }
 829
 830         i2c->irq = res;
 831
 832         dev_dbg(&pdev->dev, "irq resource %p (%lu)\n", res,
 833                 (unsigned long)res->start);
 834
 835         ret = i2c_add_adapter(&i2c->adap);
 836         if (ret < 0) {
 837                 dev_err(&pdev->dev, "failed to add bus to i2c core\n");
 838                 goto err_irq;
 839         }
 840
 841         platform_set_drvdata(pdev, i2c);
 842
 843         dev_info(&pdev->dev, "%s: S3C I2C adapter\n", i2c->adap.dev.bus_id);
 844         return 0;
 845
 846  err_irq:
 847         free_irq(i2c->irq->start, i2c);
 848
 849  err_iomap:
 850         iounmap(i2c->regs);
 851
 852  err_ioarea:
 853         release_resource(i2c->ioarea);
 854         kfree(i2c->ioarea);
 855
 856  err_clk:
 857         clk_disable(i2c->clk);
 858         clk_put(i2c->clk);
 859
 860  err_noclk:
 861         return ret;
 862 }
 863
 864 /* s3c24xx_i2c_remove
 865  *
 866  * called when device is removed from the bus
 867 */
 868
 869 static int s3c24xx_i2c_remove(struct platform_device *pdev)
 870 {
 871         struct s3c24xx_i2c *i2c = platform_get_drvdata(pdev);
 872
 873         i2c_del_adapter(&i2c->adap);
 874         free_irq(i2c->irq->start, i2c);
 875
 876         clk_disable(i2c->clk);
 877         clk_put(i2c->clk);
 878
 879         iounmap(i2c->regs);
 880
 881         release_resource(i2c->ioarea);
 882         kfree(i2c->ioarea);
 883
 884         return 0;
 885 }
 886
 887 #ifdef CONFIG_PM
 888 static int s3c24xx_i2c_resume(struct platform_device *dev)
 889 {
 890         struct s3c24xx_i2c *i2c = platform_get_drvdata(dev);
 891
 892         if (i2c != NULL)
 893                 s3c24xx_i2c_init(i2c);
 894
 895         return 0;
 896 }
 897
 898 #else
 899 #define s3c24xx_i2c_resume NULL
 900 #endif
 901
 902 /* device driver for platform bus bits */
 903
 904 static struct platform_driver s3c2410_i2c_driver = {
 905         .probe          = s3c24xx_i2c_probe,
 906         .remove         = s3c24xx_i2c_remove,
 907         .resume         = s3c24xx_i2c_resume,
 908         .driver         = {
 909                 .owner  = THIS_MODULE,
 910                 .name   = "s3c2410-i2c",
 911         },
 912 };
 913
 914 static struct platform_driver s3c2440_i2c_driver = {
 915         .probe          = s3c24xx_i2c_probe,
 916         .remove         = s3c24xx_i2c_remove,
 917         .resume         = s3c24xx_i2c_resume,
 918         .driver         = {
 919                 .owner  = THIS_MODULE,
 920                 .name   = "s3c2440-i2c",
 921         },
 922 };
 923
 924 static int __init i2c_adap_s3c_init(void)
 925 {
 926         int ret;
 927
 928         ret = platform_driver_register(&s3c2410_i2c_driver);
 929         if (ret == 0) {
 930                 ret = platform_driver_register(&s3c2440_i2c_driver);
 931                 if (ret)
 932                         platform_driver_unregister(&s3c2410_i2c_driver);
 933         }
 934
 935         return ret;
 936 }
 937
 938 static void __exit i2c_adap_s3c_exit(void)
 939 {
 940         platform_driver_unregister(&s3c2410_i2c_driver);
 941         platform_driver_unregister(&s3c2440_i2c_driver);
 942 }
 943
 944 module_init(i2c_adap_s3c_init);
 945 module_exit(i2c_adap_s3c_exit);
 946
 947 MODULE_DESCRIPTION("S3C24XX I2C Bus driver");
 948 MODULE_AUTHOR("Ben Dooks, <ben@simtec.co.uk>");
 949 MODULE_LICENSE("GPL");
 950 MODULE_ALIAS("platform:s3c2410-i2c");
 951 MODULE_ALIAS("platform:s3c2440-i2c");