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/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 #include <linux/slab.h>
  38
  39 #include <asm/irq.h>
  40 #include <asm/io.h>
  41
  42 #include <plat/regs-iic.h>
  43 #include <plat/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 enum s3c24xx_i2c_type {
  56         TYPE_S3C2410,
  57         TYPE_S3C2440,
  58 };
  59
  60 struct s3c24xx_i2c {
  61         spinlock_t              lock;
  62         wait_queue_head_t       wait;
  63         unsigned int            suspended:1;
  64
  65         struct i2c_msg          *msg;
  66         unsigned int            msg_num;
  67         unsigned int            msg_idx;
  68         unsigned int            msg_ptr;
  69
  70         unsigned int            tx_setup;
  71         unsigned int            irq;
  72
  73         enum s3c24xx_i2c_state  state;
  74         unsigned long           clkrate;
  75
  76         void __iomem            *regs;
  77         struct clk              *clk;
  78         struct device           *dev;
  79         struct resource         *ioarea;
  80         struct i2c_adapter      adap;
  81
  82 #ifdef CONFIG_CPU_FREQ
  83         struct notifier_block   freq_transition;
  84 #endif
  85 };
  86
  87 /* default platform data removed, dev should always carry data. */
  88
  89 /* s3c24xx_i2c_is2440()
  90  *
  91  * return true is this is an s3c2440
  92 */
  93
  94 static inline int s3c24xx_i2c_is2440(struct s3c24xx_i2c *i2c)
  95 {
  96         struct platform_device *pdev = to_platform_device(i2c->dev);
  97         enum s3c24xx_i2c_type type;
  98
  99         type = platform_get_device_id(pdev)->driver_data;
 100         return type == TYPE_S3C2440;
 101 }
 102
 103 /* s3c24xx_i2c_master_complete
 104  *
 105  * complete the message and wake up the caller, using the given return code,
 106  * or zero to mean ok.
 107 */
 108
 109 static inline void s3c24xx_i2c_master_complete(struct s3c24xx_i2c *i2c, int ret)
 110 {
 111         dev_dbg(i2c->dev, "master_complete %d\n", ret);
 112
 113         i2c->msg_ptr = 0;
 114         i2c->msg = NULL;
 115         i2c->msg_idx++;
 116         i2c->msg_num = 0;
 117         if (ret)
 118                 i2c->msg_idx = ret;
 119
 120         wake_up(&i2c->wait);
 121 }
 122
 123 static inline void s3c24xx_i2c_disable_ack(struct s3c24xx_i2c *i2c)
 124 {
 125         unsigned long tmp;
 126
 127         tmp = readl(i2c->regs + S3C2410_IICCON);
 128         writel(tmp & ~S3C2410_IICCON_ACKEN, i2c->regs + S3C2410_IICCON);
 129 }
 130
 131 static inline void s3c24xx_i2c_enable_ack(struct s3c24xx_i2c *i2c)
 132 {
 133         unsigned long tmp;
 134
 135         tmp = readl(i2c->regs + S3C2410_IICCON);
 136         writel(tmp | S3C2410_IICCON_ACKEN, i2c->regs + S3C2410_IICCON);
 137 }
 138
 139 /* irq enable/disable functions */
 140
 141 static inline void s3c24xx_i2c_disable_irq(struct s3c24xx_i2c *i2c)
 142 {
 143         unsigned long tmp;
 144
 145         tmp = readl(i2c->regs + S3C2410_IICCON);
 146         writel(tmp & ~S3C2410_IICCON_IRQEN, i2c->regs + S3C2410_IICCON);
 147 }
 148
 149 static inline void s3c24xx_i2c_enable_irq(struct s3c24xx_i2c *i2c)
 150 {
 151         unsigned long tmp;
 152
 153         tmp = readl(i2c->regs + S3C2410_IICCON);
 154         writel(tmp | S3C2410_IICCON_IRQEN, i2c->regs + S3C2410_IICCON);
 155 }
 156
 157
 158 /* s3c24xx_i2c_message_start
 159  *
 160  * put the start of a message onto the bus
 161 */
 162
 163 static void s3c24xx_i2c_message_start(struct s3c24xx_i2c *i2c,
 164                                       struct i2c_msg *msg)
 165 {
 166         unsigned int addr = (msg->addr & 0x7f) << 1;
 167         unsigned long stat;
 168         unsigned long iiccon;
 169
 170         stat = 0;
 171         stat |=  S3C2410_IICSTAT_TXRXEN;
 172
 173         if (msg->flags & I2C_M_RD) {
 174                 stat |= S3C2410_IICSTAT_MASTER_RX;
 175                 addr |= 1;
 176         } else
 177                 stat |= S3C2410_IICSTAT_MASTER_TX;
 178
 179         if (msg->flags & I2C_M_REV_DIR_ADDR)
 180                 addr ^= 1;
 181
 182         /* todo - check for wether ack wanted or not */
 183         s3c24xx_i2c_enable_ack(i2c);
 184
 185         iiccon = readl(i2c->regs + S3C2410_IICCON);
 186         writel(stat, i2c->regs + S3C2410_IICSTAT);
 187
 188         dev_dbg(i2c->dev, "START: %08lx to IICSTAT, %02x to DS\n", stat, addr);
 189         writeb(addr, i2c->regs + S3C2410_IICDS);
 190
 191         /* delay here to ensure the data byte has gotten onto the bus
 192          * before the transaction is started */
 193
 194         ndelay(i2c->tx_setup);
 195
 196         dev_dbg(i2c->dev, "iiccon, %08lx\n", iiccon);
 197         writel(iiccon, i2c->regs + S3C2410_IICCON);
 198
 199         stat |= S3C2410_IICSTAT_START;
 200         writel(stat, i2c->regs + S3C2410_IICSTAT);
 201 }
 202
 203 static inline void s3c24xx_i2c_stop(struct s3c24xx_i2c *i2c, int ret)
 204 {
 205         unsigned long iicstat = readl(i2c->regs + S3C2410_IICSTAT);
 206
 207         dev_dbg(i2c->dev, "STOP\n");
 208
 209         /* stop the transfer */
 210         iicstat &= ~S3C2410_IICSTAT_START;
 211         writel(iicstat, i2c->regs + S3C2410_IICSTAT);
 212
 213         i2c->state = STATE_STOP;
 214
 215         s3c24xx_i2c_master_complete(i2c, ret);
 216         s3c24xx_i2c_disable_irq(i2c);
 217 }
 218
 219 /* helper functions to determine the current state in the set of
 220  * messages we are sending */
 221
 222 /* is_lastmsg()
 223  *
 224  * returns TRUE if the current message is the last in the set
 225 */
 226
 227 static inline int is_lastmsg(struct s3c24xx_i2c *i2c)
 228 {
 229         return i2c->msg_idx >= (i2c->msg_num - 1);
 230 }
 231
 232 /* is_msglast
 233  *
 234  * returns TRUE if we this is the last byte in the current message
 235 */
 236
 237 static inline int is_msglast(struct s3c24xx_i2c *i2c)
 238 {
 239         return i2c->msg_ptr == i2c->msg->len-1;
 240 }
 241
 242 /* is_msgend
 243  *
 244  * returns TRUE if we reached the end of the current message
 245 */
 246
 247 static inline int is_msgend(struct s3c24xx_i2c *i2c)
 248 {
 249         return i2c->msg_ptr >= i2c->msg->len;
 250 }
 251
 252 /* i2s_s3c_irq_nextbyte
 253  *
 254  * process an interrupt and work out what to do
 255  */
 256
 257 static int i2s_s3c_irq_nextbyte(struct s3c24xx_i2c *i2c, unsigned long iicstat)
 258 {
 259         unsigned long tmp;
 260         unsigned char byte;
 261         int ret = 0;
 262
 263         switch (i2c->state) {
 264
 265         case STATE_IDLE:
 266                 dev_err(i2c->dev, "%s: called in STATE_IDLE\n", __func__);
 267                 goto out;
 268                 break;
 269
 270         case STATE_STOP:
 271                 dev_err(i2c->dev, "%s: called in STATE_STOP\n", __func__);
 272                 s3c24xx_i2c_disable_irq(i2c);
 273                 goto out_ack;
 274
 275         case STATE_START:
 276                 /* last thing we did was send a start condition on the
 277                  * bus, or started a new i2c message
 278                  */
 279
 280                 if (iicstat & S3C2410_IICSTAT_LASTBIT &&
 281                     !(i2c->msg->flags & I2C_M_IGNORE_NAK)) {
 282                         /* ack was not received... */
 283
 284                         dev_dbg(i2c->dev, "ack was not received\n");
 285                         s3c24xx_i2c_stop(i2c, -ENXIO);
 286                         goto out_ack;
 287                 }
 288
 289                 if (i2c->msg->flags & I2C_M_RD)
 290                         i2c->state = STATE_READ;
 291                 else
 292                         i2c->state = STATE_WRITE;
 293
 294                 /* terminate the transfer if there is nothing to do
 295                  * as this is used by the i2c probe to find devices. */
 296
 297                 if (is_lastmsg(i2c) && i2c->msg->len == 0) {
 298                         s3c24xx_i2c_stop(i2c, 0);
 299                         goto out_ack;
 300                 }
 301
 302                 if (i2c->state == STATE_READ)
 303                         goto prepare_read;
 304
 305                 /* fall through to the write state, as we will need to
 306                  * send a byte as well */
 307
 308         case STATE_WRITE:
 309                 /* we are writing data to the device... check for the
 310                  * end of the message, and if so, work out what to do
 311                  */
 312
 313                 if (!(i2c->msg->flags & I2C_M_IGNORE_NAK)) {
 314                         if (iicstat & S3C2410_IICSTAT_LASTBIT) {
 315                                 dev_dbg(i2c->dev, "WRITE: No Ack\n");
 316
 317                                 s3c24xx_i2c_stop(i2c, -ECONNREFUSED);
 318                                 goto out_ack;
 319                         }
 320                 }
 321
 322  retry_write:
 323
 324                 if (!is_msgend(i2c)) {
 325                         byte = i2c->msg->buf[i2c->msg_ptr++];
 326                         writeb(byte, i2c->regs + S3C2410_IICDS);
 327
 328                         /* delay after writing the byte to allow the
 329                          * data setup time on the bus, as writing the
 330                          * data to the register causes the first bit
 331                          * to appear on SDA, and SCL will change as
 332                          * soon as the interrupt is acknowledged */
 333
 334                         ndelay(i2c->tx_setup);
 335
 336                 } else if (!is_lastmsg(i2c)) {
 337                         /* we need to go to the next i2c message */
 338
 339                         dev_dbg(i2c->dev, "WRITE: Next Message\n");
 340
 341                         i2c->msg_ptr = 0;
 342                         i2c->msg_idx++;
 343                         i2c->msg++;
 344
 345                         /* check to see if we need to do another message */
 346                         if (i2c->msg->flags & I2C_M_NOSTART) {
 347
 348                                 if (i2c->msg->flags & I2C_M_RD) {
 349                                         /* cannot do this, the controller
 350                                          * forces us to send a new START
 351                                          * when we change direction */
 352
 353                                         s3c24xx_i2c_stop(i2c, -EINVAL);
 354                                 }
 355
 356                                 goto retry_write;
 357                         } else {
 358                                 /* send the new start */
 359                                 s3c24xx_i2c_message_start(i2c, i2c->msg);
 360                                 i2c->state = STATE_START;
 361                         }
 362
 363                 } else {
 364                         /* send stop */
 365
 366                         s3c24xx_i2c_stop(i2c, 0);
 367                 }
 368                 break;
 369
 370         case STATE_READ:
 371                 /* we have a byte of data in the data register, do
 372                  * something with it, and then work out wether we are
 373                  * going to do any more read/write
 374                  */
 375
 376                 byte = readb(i2c->regs + S3C2410_IICDS);
 377                 i2c->msg->buf[i2c->msg_ptr++] = byte;
 378
 379  prepare_read:
 380                 if (is_msglast(i2c)) {
 381                         /* last byte of buffer */
 382
 383                         if (is_lastmsg(i2c))
 384                                 s3c24xx_i2c_disable_ack(i2c);
 385
 386                 } else if (is_msgend(i2c)) {
 387                         /* ok, we've read the entire buffer, see if there
 388                          * is anything else we need to do */
 389
 390                         if (is_lastmsg(i2c)) {
 391                                 /* last message, send stop and complete */
 392                                 dev_dbg(i2c->dev, "READ: Send Stop\n");
 393
 394                                 s3c24xx_i2c_stop(i2c, 0);
 395                         } else {
 396                                 /* go to the next transfer */
 397                                 dev_dbg(i2c->dev, "READ: Next Transfer\n");
 398
 399                                 i2c->msg_ptr = 0;
 400                                 i2c->msg_idx++;
 401                                 i2c->msg++;
 402                         }
 403                 }
 404
 405                 break;
 406         }
 407
 408         /* acknowlegde the IRQ and get back on with the work */
 409
 410  out_ack:
 411         tmp = readl(i2c->regs + S3C2410_IICCON);
 412         tmp &= ~S3C2410_IICCON_IRQPEND;
 413         writel(tmp, i2c->regs + S3C2410_IICCON);
 414  out:
 415         return ret;
 416 }
 417
 418 /* s3c24xx_i2c_irq
 419  *
 420  * top level IRQ servicing routine
 421 */
 422
 423 static irqreturn_t s3c24xx_i2c_irq(int irqno, void *dev_id)
 424 {
 425         struct s3c24xx_i2c *i2c = dev_id;
 426         unsigned long status;
 427         unsigned long tmp;
 428
 429         status = readl(i2c->regs + S3C2410_IICSTAT);
 430
 431         if (status & S3C2410_IICSTAT_ARBITR) {
 432                 /* deal with arbitration loss */
 433                 dev_err(i2c->dev, "deal with arbitration loss\n");
 434         }
 435
 436         if (i2c->state == STATE_IDLE) {
 437                 dev_dbg(i2c->dev, "IRQ: error i2c->state == IDLE\n");
 438
 439                 tmp = readl(i2c->regs + S3C2410_IICCON);
 440                 tmp &= ~S3C2410_IICCON_IRQPEND;
 441                 writel(tmp, i2c->regs +  S3C2410_IICCON);
 442                 goto out;
 443         }
 444
 445         /* pretty much this leaves us with the fact that we've
 446          * transmitted or received whatever byte we last sent */
 447
 448         i2s_s3c_irq_nextbyte(i2c, status);
 449
 450  out:
 451         return IRQ_HANDLED;
 452 }
 453
 454
 455 /* s3c24xx_i2c_set_master
 456  *
 457  * get the i2c bus for a master transaction
 458 */
 459
 460 static int s3c24xx_i2c_set_master(struct s3c24xx_i2c *i2c)
 461 {
 462         unsigned long iicstat;
 463         int timeout = 400;
 464
 465         while (timeout-- > 0) {
 466                 iicstat = readl(i2c->regs + S3C2410_IICSTAT);
 467
 468                 if (!(iicstat & S3C2410_IICSTAT_BUSBUSY))
 469                         return 0;
 470
 471                 msleep(1);
 472         }
 473
 474         return -ETIMEDOUT;
 475 }
 476
 477 /* s3c24xx_i2c_doxfer
 478  *
 479  * this starts an i2c transfer
 480 */
 481
 482 static int s3c24xx_i2c_doxfer(struct s3c24xx_i2c *i2c,
 483                               struct i2c_msg *msgs, int num)
 484 {
 485         unsigned long timeout;
 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         msleep(1);
 525
 526  out:
 527         return ret;
 528 }
 529
 530 /* s3c24xx_i2c_xfer
 531  *
 532  * first port of call from the i2c bus code when an message needs
 533  * transferring across the i2c bus.
 534 */
 535
 536 static int s3c24xx_i2c_xfer(struct i2c_adapter *adap,
 537                         struct i2c_msg *msgs, int num)
 538 {
 539         struct s3c24xx_i2c *i2c = (struct s3c24xx_i2c *)adap->algo_data;
 540         int retry;
 541         int ret;
 542
 543         for (retry = 0; retry < adap->retries; retry++) {
 544
 545                 ret = s3c24xx_i2c_doxfer(i2c, msgs, num);
 546
 547                 if (ret != -EAGAIN)
 548                         return ret;
 549
 550                 dev_dbg(i2c->dev, "Retrying transmission (%d)\n", retry);
 551
 552                 udelay(100);
 553         }
 554
 555         return -EREMOTEIO;
 556 }
 557
 558 /* declare our i2c functionality */
 559 static u32 s3c24xx_i2c_func(struct i2c_adapter *adap)
 560 {
 561         return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_PROTOCOL_MANGLING;
 562 }
 563
 564 /* i2c bus registration info */
 565
 566 static const struct i2c_algorithm s3c24xx_i2c_algorithm = {
 567         .master_xfer            = s3c24xx_i2c_xfer,
 568         .functionality          = s3c24xx_i2c_func,
 569 };
 570
 571 /* s3c24xx_i2c_calcdivisor
 572  *
 573  * return the divisor settings for a given frequency
 574 */
 575
 576 static int s3c24xx_i2c_calcdivisor(unsigned long clkin, unsigned int wanted,
 577                                    unsigned int *div1, unsigned int *divs)
 578 {
 579         unsigned int calc_divs = clkin / wanted;
 580         unsigned int calc_div1;
 581
 582         if (calc_divs > (16*16))
 583                 calc_div1 = 512;
 584         else
 585                 calc_div1 = 16;
 586
 587         calc_divs += calc_div1-1;
 588         calc_divs /= calc_div1;
 589
 590         if (calc_divs == 0)
 591                 calc_divs = 1;
 592         if (calc_divs > 17)
 593                 calc_divs = 17;
 594
 595         *divs = calc_divs;
 596         *div1 = calc_div1;
 597
 598         return clkin / (calc_divs * calc_div1);
 599 }
 600
 601 /* s3c24xx_i2c_clockrate
 602  *
 603  * work out a divisor for the user requested frequency setting,
 604  * either by the requested frequency, or scanning the acceptable
 605  * range of frequencies until something is found
 606 */
 607
 608 static int s3c24xx_i2c_clockrate(struct s3c24xx_i2c *i2c, unsigned int *got)
 609 {
 610         struct s3c2410_platform_i2c *pdata = i2c->dev->platform_data;
 611         unsigned long clkin = clk_get_rate(i2c->clk);
 612         unsigned int divs, div1;
 613         unsigned long target_frequency;
 614         u32 iiccon;
 615         int freq;
 616
 617         i2c->clkrate = clkin;
 618         clkin /= 1000;          /* clkin now in KHz */
 619
 620         dev_dbg(i2c->dev, "pdata desired frequency %lu\n", pdata->frequency);
 621
 622         target_frequency = pdata->frequency ? pdata->frequency : 100000;
 623
 624         target_frequency /= 1000; /* Target frequency now in KHz */
 625
 626         freq = s3c24xx_i2c_calcdivisor(clkin, target_frequency, &div1, &divs);
 627
 628         if (freq > target_frequency) {
 629                 dev_err(i2c->dev,
 630                         "Unable to achieve desired frequency %luKHz."   \
 631                         " Lowest achievable %dKHz\n", target_frequency, freq);
 632                 return -EINVAL;
 633         }
 634
 635         *got = freq;
 636
 637         iiccon = readl(i2c->regs + S3C2410_IICCON);
 638         iiccon &= ~(S3C2410_IICCON_SCALEMASK | S3C2410_IICCON_TXDIV_512);
 639         iiccon |= (divs-1);
 640
 641         if (div1 == 512)
 642                 iiccon |= S3C2410_IICCON_TXDIV_512;
 643
 644         writel(iiccon, i2c->regs + S3C2410_IICCON);
 645
 646         if (s3c24xx_i2c_is2440(i2c)) {
 647                 unsigned long sda_delay;
 648
 649                 if (pdata->sda_delay) {
 650                         sda_delay = (freq / 1000) * pdata->sda_delay;
 651                         sda_delay /= 1000000;
 652                         sda_delay = DIV_ROUND_UP(sda_delay, 5);
 653                         if (sda_delay > 3)
 654                                 sda_delay = 3;
 655                         sda_delay |= S3C2410_IICLC_FILTER_ON;
 656                 } else
 657                         sda_delay = 0;
 658
 659                 dev_dbg(i2c->dev, "IICLC=%08lx\n", sda_delay);
 660                 writel(sda_delay, i2c->regs + S3C2440_IICLC);
 661         }
 662
 663         return 0;
 664 }
 665
 666 #ifdef CONFIG_CPU_FREQ
 667
 668 #define freq_to_i2c(_n) container_of(_n, struct s3c24xx_i2c, freq_transition)
 669
 670 static int s3c24xx_i2c_cpufreq_transition(struct notifier_block *nb,
 671                                           unsigned long val, void *data)
 672 {
 673         struct s3c24xx_i2c *i2c = freq_to_i2c(nb);
 674         unsigned long flags;
 675         unsigned int got;
 676         int delta_f;
 677         int ret;
 678
 679         delta_f = clk_get_rate(i2c->clk) - i2c->clkrate;
 680
 681         /* if we're post-change and the input clock has slowed down
 682          * or at pre-change and the clock is about to speed up, then
 683          * adjust our clock rate. <0 is slow, >0 speedup.
 684          */
 685
 686         if ((val == CPUFREQ_POSTCHANGE && delta_f < 0) ||
 687             (val == CPUFREQ_PRECHANGE && delta_f > 0)) {
 688                 spin_lock_irqsave(&i2c->lock, flags);
 689                 ret = s3c24xx_i2c_clockrate(i2c, &got);
 690                 spin_unlock_irqrestore(&i2c->lock, flags);
 691
 692                 if (ret < 0)
 693                         dev_err(i2c->dev, "cannot find frequency\n");
 694                 else
 695                         dev_info(i2c->dev, "setting freq %d\n", got);
 696         }
 697
 698         return 0;
 699 }
 700
 701 static inline int s3c24xx_i2c_register_cpufreq(struct s3c24xx_i2c *i2c)
 702 {
 703         i2c->freq_transition.notifier_call = s3c24xx_i2c_cpufreq_transition;
 704
 705         return cpufreq_register_notifier(&i2c->freq_transition,
 706                                          CPUFREQ_TRANSITION_NOTIFIER);
 707 }
 708
 709 static inline void s3c24xx_i2c_deregister_cpufreq(struct s3c24xx_i2c *i2c)
 710 {
 711         cpufreq_unregister_notifier(&i2c->freq_transition,
 712                                     CPUFREQ_TRANSITION_NOTIFIER);
 713 }
 714
 715 #else
 716 static inline int s3c24xx_i2c_register_cpufreq(struct s3c24xx_i2c *i2c)
 717 {
 718         return 0;
 719 }
 720
 721 static inline void s3c24xx_i2c_deregister_cpufreq(struct s3c24xx_i2c *i2c)
 722 {
 723 }
 724 #endif
 725
 726 /* s3c24xx_i2c_init
 727  *
 728  * initialise the controller, set the IO lines and frequency
 729 */
 730
 731 static int s3c24xx_i2c_init(struct s3c24xx_i2c *i2c)
 732 {
 733         unsigned long iicon = S3C2410_IICCON_IRQEN | S3C2410_IICCON_ACKEN;
 734         struct s3c2410_platform_i2c *pdata;
 735         unsigned int freq;
 736
 737         /* get the plafrom data */
 738
 739         pdata = i2c->dev->platform_data;
 740
 741         /* inititalise the gpio */
 742
 743         if (pdata->cfg_gpio)
 744                 pdata->cfg_gpio(to_platform_device(i2c->dev));
 745
 746         /* write slave address */
 747
 748         writeb(pdata->slave_addr, i2c->regs + S3C2410_IICADD);
 749
 750         dev_info(i2c->dev, "slave address 0x%02x\n", pdata->slave_addr);
 751
 752         writel(iicon, i2c->regs + S3C2410_IICCON);
 753
 754         /* we need to work out the divisors for the clock... */
 755
 756         if (s3c24xx_i2c_clockrate(i2c, &freq) != 0) {
 757                 writel(0, i2c->regs + S3C2410_IICCON);
 758                 dev_err(i2c->dev, "cannot meet bus frequency required\n");
 759                 return -EINVAL;
 760         }
 761
 762         /* todo - check that the i2c lines aren't being dragged anywhere */
 763
 764         dev_info(i2c->dev, "bus frequency set to %d KHz\n", freq);
 765         dev_dbg(i2c->dev, "S3C2410_IICCON=0x%02lx\n", iicon);
 766
 767         return 0;
 768 }
 769
 770 /* s3c24xx_i2c_probe
 771  *
 772  * called by the bus driver when a suitable device is found
 773 */
 774
 775 static int s3c24xx_i2c_probe(struct platform_device *pdev)
 776 {
 777         struct s3c24xx_i2c *i2c;
 778         struct s3c2410_platform_i2c *pdata;
 779         struct resource *res;
 780         int ret;
 781
 782         pdata = pdev->dev.platform_data;
 783         if (!pdata) {
 784                 dev_err(&pdev->dev, "no platform data\n");
 785                 return -EINVAL;
 786         }
 787
 788         i2c = kzalloc(sizeof(struct s3c24xx_i2c), GFP_KERNEL);
 789         if (!i2c) {
 790                 dev_err(&pdev->dev, "no memory for state\n");
 791                 return -ENOMEM;
 792         }
 793
 794         strlcpy(i2c->adap.name, "s3c2410-i2c", sizeof(i2c->adap.name));
 795         i2c->adap.owner   = THIS_MODULE;
 796         i2c->adap.algo    = &s3c24xx_i2c_algorithm;
 797         i2c->adap.retries = 2;
 798         i2c->adap.class   = I2C_CLASS_HWMON | I2C_CLASS_SPD;
 799         i2c->tx_setup     = 50;
 800
 801         spin_lock_init(&i2c->lock);
 802         init_waitqueue_head(&i2c->wait);
 803
 804         /* find the clock and enable it */
 805
 806         i2c->dev = &pdev->dev;
 807         i2c->clk = clk_get(&pdev->dev, "i2c");
 808         if (IS_ERR(i2c->clk)) {
 809                 dev_err(&pdev->dev, "cannot get clock\n");
 810                 ret = -ENOENT;
 811                 goto err_noclk;
 812         }
 813
 814         dev_dbg(&pdev->dev, "clock source %p\n", i2c->clk);
 815
 816         clk_enable(i2c->clk);
 817
 818         /* map the registers */
 819
 820         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 821         if (res == NULL) {
 822                 dev_err(&pdev->dev, "cannot find IO resource\n");
 823                 ret = -ENOENT;
 824                 goto err_clk;
 825         }
 826
 827         i2c->ioarea = request_mem_region(res->start, resource_size(res),
 828                                          pdev->name);
 829
 830         if (i2c->ioarea == NULL) {
 831                 dev_err(&pdev->dev, "cannot request IO\n");
 832                 ret = -ENXIO;
 833                 goto err_clk;
 834         }
 835
 836         i2c->regs = ioremap(res->start, resource_size(res));
 837
 838         if (i2c->regs == NULL) {
 839                 dev_err(&pdev->dev, "cannot map IO\n");
 840                 ret = -ENXIO;
 841                 goto err_ioarea;
 842         }
 843
 844         dev_dbg(&pdev->dev, "registers %p (%p, %p)\n",
 845                 i2c->regs, i2c->ioarea, res);
 846
 847         /* setup info block for the i2c core */
 848
 849         i2c->adap.algo_data = i2c;
 850         i2c->adap.dev.parent = &pdev->dev;
 851
 852         /* initialise the i2c controller */
 853
 854         ret = s3c24xx_i2c_init(i2c);
 855         if (ret != 0)
 856                 goto err_iomap;
 857
 858         /* find the IRQ for this unit (note, this relies on the init call to
 859          * ensure no current IRQs pending
 860          */
 861
 862         i2c->irq = ret = platform_get_irq(pdev, 0);
 863         if (ret <= 0) {
 864                 dev_err(&pdev->dev, "cannot find IRQ\n");
 865                 goto err_iomap;
 866         }
 867
 868         ret = request_irq(i2c->irq, s3c24xx_i2c_irq, IRQF_DISABLED,
 869                           dev_name(&pdev->dev), i2c);
 870
 871         if (ret != 0) {
 872                 dev_err(&pdev->dev, "cannot claim IRQ %d\n", i2c->irq);
 873                 goto err_iomap;
 874         }
 875
 876         ret = s3c24xx_i2c_register_cpufreq(i2c);
 877         if (ret < 0) {
 878                 dev_err(&pdev->dev, "failed to register cpufreq notifier\n");
 879                 goto err_irq;
 880         }
 881
 882         /* Note, previous versions of the driver used i2c_add_adapter()
 883          * to add the bus at any number. We now pass the bus number via
 884          * the platform data, so if unset it will now default to always
 885          * being bus 0.
 886          */
 887
 888         i2c->adap.nr = pdata->bus_num;
 889
 890         ret = i2c_add_numbered_adapter(&i2c->adap);
 891         if (ret < 0) {
 892                 dev_err(&pdev->dev, "failed to add bus to i2c core\n");
 893                 goto err_cpufreq;
 894         }
 895
 896         platform_set_drvdata(pdev, i2c);
 897
 898         dev_info(&pdev->dev, "%s: S3C I2C adapter\n", dev_name(&i2c->adap.dev));
 899         return 0;
 900
 901  err_cpufreq:
 902         s3c24xx_i2c_deregister_cpufreq(i2c);
 903
 904  err_irq:
 905         free_irq(i2c->irq, i2c);
 906
 907  err_iomap:
 908         iounmap(i2c->regs);
 909
 910  err_ioarea:
 911         release_resource(i2c->ioarea);
 912         kfree(i2c->ioarea);
 913
 914  err_clk:
 915         clk_disable(i2c->clk);
 916         clk_put(i2c->clk);
 917
 918  err_noclk:
 919         kfree(i2c);
 920         return ret;
 921 }
 922
 923 /* s3c24xx_i2c_remove
 924  *
 925  * called when device is removed from the bus
 926 */
 927
 928 static int s3c24xx_i2c_remove(struct platform_device *pdev)
 929 {
 930         struct s3c24xx_i2c *i2c = platform_get_drvdata(pdev);
 931
 932         s3c24xx_i2c_deregister_cpufreq(i2c);
 933
 934         i2c_del_adapter(&i2c->adap);
 935         free_irq(i2c->irq, i2c);
 936
 937         clk_disable(i2c->clk);
 938         clk_put(i2c->clk);
 939
 940         iounmap(i2c->regs);
 941
 942         release_resource(i2c->ioarea);
 943         kfree(i2c->ioarea);
 944         kfree(i2c);
 945
 946         return 0;
 947 }
 948
 949 #ifdef CONFIG_PM
 950 static int s3c24xx_i2c_suspend_noirq(struct device *dev)
 951 {
 952         struct platform_device *pdev = to_platform_device(dev);
 953         struct s3c24xx_i2c *i2c = platform_get_drvdata(pdev);
 954
 955         i2c->suspended = 1;
 956
 957         return 0;
 958 }
 959
 960 static int s3c24xx_i2c_resume(struct device *dev)
 961 {
 962         struct platform_device *pdev = to_platform_device(dev);
 963         struct s3c24xx_i2c *i2c = platform_get_drvdata(pdev);
 964
 965         i2c->suspended = 0;
 966         s3c24xx_i2c_init(i2c);
 967
 968         return 0;
 969 }
 970
 971 static const struct dev_pm_ops s3c24xx_i2c_dev_pm_ops = {
 972         .suspend_noirq = s3c24xx_i2c_suspend_noirq,
 973         .resume = s3c24xx_i2c_resume,
 974 };
 975
 976 #define S3C24XX_DEV_PM_OPS (&s3c24xx_i2c_dev_pm_ops)
 977 #else
 978 #define S3C24XX_DEV_PM_OPS NULL
 979 #endif
 980
 981 /* device driver for platform bus bits */
 982
 983 static struct platform_device_id s3c24xx_driver_ids[] = {
 984         {
 985                 .name           = "s3c2410-i2c",
 986                 .driver_data    = TYPE_S3C2410,
 987         }, {
 988                 .name           = "s3c2440-i2c",
 989                 .driver_data    = TYPE_S3C2440,
 990         }, { },
 991 };
 992 MODULE_DEVICE_TABLE(platform, s3c24xx_driver_ids);
 993
 994 static struct platform_driver s3c24xx_i2c_driver = {
 995         .probe          = s3c24xx_i2c_probe,
 996         .remove         = s3c24xx_i2c_remove,
 997         .id_table       = s3c24xx_driver_ids,
 998         .driver         = {
 999                 .owner  = THIS_MODULE,
1000                 .name   = "s3c-i2c",
1001                 .pm     = S3C24XX_DEV_PM_OPS,
1002         },
1003 };
1004
1005 static int __init i2c_adap_s3c_init(void)
1006 {
1007         return platform_driver_register(&s3c24xx_i2c_driver);
1008 }
1009 subsys_initcall(i2c_adap_s3c_init);
1010
1011 static void __exit i2c_adap_s3c_exit(void)
1012 {
1013         platform_driver_unregister(&s3c24xx_i2c_driver);
1014 }
1015 module_exit(i2c_adap_s3c_exit);
1016
1017 MODULE_DESCRIPTION("S3C24XX I2C Bus driver");
1018 MODULE_AUTHOR("Ben Dooks, <ben@simtec.co.uk>");
1019 MODULE_LICENSE("GPL");