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 #include <linux/of_i2c.h>
  39 #include <linux/of_gpio.h>
  40
  41 #include <asm/irq.h>
  42
  43 #include <plat/regs-iic.h>
  44 #include <plat/iic.h>
  45
  46 /* i2c controller state */
  47
  48 enum s3c24xx_i2c_state {
  49         STATE_IDLE,
  50         STATE_START,
  51         STATE_READ,
  52         STATE_WRITE,
  53         STATE_STOP
  54 };
  55
  56 enum s3c24xx_i2c_type {
  57         TYPE_S3C2410,
  58         TYPE_S3C2440,
  59 };
  60
  61 struct s3c24xx_i2c {
  62         spinlock_t              lock;
  63         wait_queue_head_t       wait;
  64         unsigned int            suspended:1;
  65
  66         struct i2c_msg          *msg;
  67         unsigned int            msg_num;
  68         unsigned int            msg_idx;
  69         unsigned int            msg_ptr;
  70
  71         unsigned int            tx_setup;
  72         unsigned int            irq;
  73
  74         enum s3c24xx_i2c_state  state;
  75         unsigned long           clkrate;
  76
  77         void __iomem            *regs;
  78         struct clk              *clk;
  79         struct device           *dev;
  80         struct resource         *ioarea;
  81         struct i2c_adapter      adap;
  82
  83         struct s3c2410_platform_i2c     *pdata;
  84         int                     gpios[2];
  85 #ifdef CONFIG_CPU_FREQ
  86         struct notifier_block   freq_transition;
  87 #endif
  88 };
  89
  90 /* default platform data removed, dev should always carry data. */
  91
  92 /* s3c24xx_i2c_is2440()
  93  *
  94  * return true is this is an s3c2440
  95 */
  96
  97 static inline int s3c24xx_i2c_is2440(struct s3c24xx_i2c *i2c)
  98 {
  99         struct platform_device *pdev = to_platform_device(i2c->dev);
 100         enum s3c24xx_i2c_type type;
 101
 102 #ifdef CONFIG_OF
 103         if (i2c->dev->of_node)
 104                 return of_device_is_compatible(i2c->dev->of_node,
 105                                 "samsung,s3c2440-i2c");
 106 #endif
 107
 108         type = platform_get_device_id(pdev)->driver_data;
 109         return type == TYPE_S3C2440;
 110 }
 111
 112 /* s3c24xx_i2c_master_complete
 113  *
 114  * complete the message and wake up the caller, using the given return code,
 115  * or zero to mean ok.
 116 */
 117
 118 static inline void s3c24xx_i2c_master_complete(struct s3c24xx_i2c *i2c, int ret)
 119 {
 120         dev_dbg(i2c->dev, "master_complete %d\n", ret);
 121
 122         i2c->msg_ptr = 0;
 123         i2c->msg = NULL;
 124         i2c->msg_idx++;
 125         i2c->msg_num = 0;
 126         if (ret)
 127                 i2c->msg_idx = ret;
 128
 129         wake_up(&i2c->wait);
 130 }
 131
 132 static inline void s3c24xx_i2c_disable_ack(struct s3c24xx_i2c *i2c)
 133 {
 134         unsigned long tmp;
 135
 136         tmp = readl(i2c->regs + S3C2410_IICCON);
 137         writel(tmp & ~S3C2410_IICCON_ACKEN, i2c->regs + S3C2410_IICCON);
 138 }
 139
 140 static inline void s3c24xx_i2c_enable_ack(struct s3c24xx_i2c *i2c)
 141 {
 142         unsigned long tmp;
 143
 144         tmp = readl(i2c->regs + S3C2410_IICCON);
 145         writel(tmp | S3C2410_IICCON_ACKEN, i2c->regs + S3C2410_IICCON);
 146 }
 147
 148 /* irq enable/disable functions */
 149
 150 static inline void s3c24xx_i2c_disable_irq(struct s3c24xx_i2c *i2c)
 151 {
 152         unsigned long tmp;
 153
 154         tmp = readl(i2c->regs + S3C2410_IICCON);
 155         writel(tmp & ~S3C2410_IICCON_IRQEN, i2c->regs + S3C2410_IICCON);
 156 }
 157
 158 static inline void s3c24xx_i2c_enable_irq(struct s3c24xx_i2c *i2c)
 159 {
 160         unsigned long tmp;
 161
 162         tmp = readl(i2c->regs + S3C2410_IICCON);
 163         writel(tmp | S3C2410_IICCON_IRQEN, i2c->regs + S3C2410_IICCON);
 164 }
 165
 166
 167 /* s3c24xx_i2c_message_start
 168  *
 169  * put the start of a message onto the bus
 170 */
 171
 172 static void s3c24xx_i2c_message_start(struct s3c24xx_i2c *i2c,
 173                                       struct i2c_msg *msg)
 174 {
 175         unsigned int addr = (msg->addr & 0x7f) << 1;
 176         unsigned long stat;
 177         unsigned long iiccon;
 178
 179         stat = 0;
 180         stat |=  S3C2410_IICSTAT_TXRXEN;
 181
 182         if (msg->flags & I2C_M_RD) {
 183                 stat |= S3C2410_IICSTAT_MASTER_RX;
 184                 addr |= 1;
 185         } else
 186                 stat |= S3C2410_IICSTAT_MASTER_TX;
 187
 188         if (msg->flags & I2C_M_REV_DIR_ADDR)
 189                 addr ^= 1;
 190
 191         /* todo - check for wether ack wanted or not */
 192         s3c24xx_i2c_enable_ack(i2c);
 193
 194         iiccon = readl(i2c->regs + S3C2410_IICCON);
 195         writel(stat, i2c->regs + S3C2410_IICSTAT);
 196
 197         dev_dbg(i2c->dev, "START: %08lx to IICSTAT, %02x to DS\n", stat, addr);
 198         writeb(addr, i2c->regs + S3C2410_IICDS);
 199
 200         /* delay here to ensure the data byte has gotten onto the bus
 201          * before the transaction is started */
 202
 203         ndelay(i2c->tx_setup);
 204
 205         dev_dbg(i2c->dev, "iiccon, %08lx\n", iiccon);
 206         writel(iiccon, i2c->regs + S3C2410_IICCON);
 207
 208         stat |= S3C2410_IICSTAT_START;
 209         writel(stat, i2c->regs + S3C2410_IICSTAT);
 210 }
 211
 212 static inline void s3c24xx_i2c_stop(struct s3c24xx_i2c *i2c, int ret)
 213 {
 214         unsigned long iicstat = readl(i2c->regs + S3C2410_IICSTAT);
 215
 216         dev_dbg(i2c->dev, "STOP\n");
 217
 218         /* stop the transfer */
 219         iicstat &= ~S3C2410_IICSTAT_START;
 220         writel(iicstat, i2c->regs + S3C2410_IICSTAT);
 221
 222         i2c->state = STATE_STOP;
 223
 224         s3c24xx_i2c_master_complete(i2c, ret);
 225         s3c24xx_i2c_disable_irq(i2c);
 226 }
 227
 228 /* helper functions to determine the current state in the set of
 229  * messages we are sending */
 230
 231 /* is_lastmsg()
 232  *
 233  * returns TRUE if the current message is the last in the set
 234 */
 235
 236 static inline int is_lastmsg(struct s3c24xx_i2c *i2c)
 237 {
 238         return i2c->msg_idx >= (i2c->msg_num - 1);
 239 }
 240
 241 /* is_msglast
 242  *
 243  * returns TRUE if we this is the last byte in the current message
 244 */
 245
 246 static inline int is_msglast(struct s3c24xx_i2c *i2c)
 247 {
 248         return i2c->msg_ptr == i2c->msg->len-1;
 249 }
 250
 251 /* is_msgend
 252  *
 253  * returns TRUE if we reached the end of the current message
 254 */
 255
 256 static inline int is_msgend(struct s3c24xx_i2c *i2c)
 257 {
 258         return i2c->msg_ptr >= i2c->msg->len;
 259 }
 260
 261 /* i2c_s3c_irq_nextbyte
 262  *
 263  * process an interrupt and work out what to do
 264  */
 265
 266 static int i2c_s3c_irq_nextbyte(struct s3c24xx_i2c *i2c, unsigned long iicstat)
 267 {
 268         unsigned long tmp;
 269         unsigned char byte;
 270         int ret = 0;
 271
 272         switch (i2c->state) {
 273
 274         case STATE_IDLE:
 275                 dev_err(i2c->dev, "%s: called in STATE_IDLE\n", __func__);
 276                 goto out;
 277
 278         case STATE_STOP:
 279                 dev_err(i2c->dev, "%s: called in STATE_STOP\n", __func__);
 280                 s3c24xx_i2c_disable_irq(i2c);
 281                 goto out_ack;
 282
 283         case STATE_START:
 284                 /* last thing we did was send a start condition on the
 285                  * bus, or started a new i2c message
 286                  */
 287
 288                 if (iicstat & S3C2410_IICSTAT_LASTBIT &&
 289                     !(i2c->msg->flags & I2C_M_IGNORE_NAK)) {
 290                         /* ack was not received... */
 291
 292                         dev_dbg(i2c->dev, "ack was not received\n");
 293                         s3c24xx_i2c_stop(i2c, -ENXIO);
 294                         goto out_ack;
 295                 }
 296
 297                 if (i2c->msg->flags & I2C_M_RD)
 298                         i2c->state = STATE_READ;
 299                 else
 300                         i2c->state = STATE_WRITE;
 301
 302                 /* terminate the transfer if there is nothing to do
 303                  * as this is used by the i2c probe to find devices. */
 304
 305                 if (is_lastmsg(i2c) && i2c->msg->len == 0) {
 306                         s3c24xx_i2c_stop(i2c, 0);
 307                         goto out_ack;
 308                 }
 309
 310                 if (i2c->state == STATE_READ)
 311                         goto prepare_read;
 312
 313                 /* fall through to the write state, as we will need to
 314                  * send a byte as well */
 315
 316         case STATE_WRITE:
 317                 /* we are writing data to the device... check for the
 318                  * end of the message, and if so, work out what to do
 319                  */
 320
 321                 if (!(i2c->msg->flags & I2C_M_IGNORE_NAK)) {
 322                         if (iicstat & S3C2410_IICSTAT_LASTBIT) {
 323                                 dev_dbg(i2c->dev, "WRITE: No Ack\n");
 324
 325                                 s3c24xx_i2c_stop(i2c, -ECONNREFUSED);
 326                                 goto out_ack;
 327                         }
 328                 }
 329
 330  retry_write:
 331
 332                 if (!is_msgend(i2c)) {
 333                         byte = i2c->msg->buf[i2c->msg_ptr++];
 334                         writeb(byte, i2c->regs + S3C2410_IICDS);
 335
 336                         /* delay after writing the byte to allow the
 337                          * data setup time on the bus, as writing the
 338                          * data to the register causes the first bit
 339                          * to appear on SDA, and SCL will change as
 340                          * soon as the interrupt is acknowledged */
 341
 342                         ndelay(i2c->tx_setup);
 343
 344                 } else if (!is_lastmsg(i2c)) {
 345                         /* we need to go to the next i2c message */
 346
 347                         dev_dbg(i2c->dev, "WRITE: Next Message\n");
 348
 349                         i2c->msg_ptr = 0;
 350                         i2c->msg_idx++;
 351                         i2c->msg++;
 352
 353                         /* check to see if we need to do another message */
 354                         if (i2c->msg->flags & I2C_M_NOSTART) {
 355
 356                                 if (i2c->msg->flags & I2C_M_RD) {
 357                                         /* cannot do this, the controller
 358                                          * forces us to send a new START
 359                                          * when we change direction */
 360
 361                                         s3c24xx_i2c_stop(i2c, -EINVAL);
 362                                 }
 363
 364                                 goto retry_write;
 365                         } else {
 366                                 /* send the new start */
 367                                 s3c24xx_i2c_message_start(i2c, i2c->msg);
 368                                 i2c->state = STATE_START;
 369                         }
 370
 371                 } else {
 372                         /* send stop */
 373
 374                         s3c24xx_i2c_stop(i2c, 0);
 375                 }
 376                 break;
 377
 378         case STATE_READ:
 379                 /* we have a byte of data in the data register, do
 380                  * something with it, and then work out wether we are
 381                  * going to do any more read/write
 382                  */
 383
 384                 byte = readb(i2c->regs + S3C2410_IICDS);
 385                 i2c->msg->buf[i2c->msg_ptr++] = byte;
 386
 387  prepare_read:
 388                 if (is_msglast(i2c)) {
 389                         /* last byte of buffer */
 390
 391                         if (is_lastmsg(i2c))
 392                                 s3c24xx_i2c_disable_ack(i2c);
 393
 394                 } else if (is_msgend(i2c)) {
 395                         /* ok, we've read the entire buffer, see if there
 396                          * is anything else we need to do */
 397
 398                         if (is_lastmsg(i2c)) {
 399                                 /* last message, send stop and complete */
 400                                 dev_dbg(i2c->dev, "READ: Send Stop\n");
 401
 402                                 s3c24xx_i2c_stop(i2c, 0);
 403                         } else {
 404                                 /* go to the next transfer */
 405                                 dev_dbg(i2c->dev, "READ: Next Transfer\n");
 406
 407                                 i2c->msg_ptr = 0;
 408                                 i2c->msg_idx++;
 409                                 i2c->msg++;
 410                         }
 411                 }
 412
 413                 break;
 414         }
 415
 416         /* acknowlegde the IRQ and get back on with the work */
 417
 418  out_ack:
 419         tmp = readl(i2c->regs + S3C2410_IICCON);
 420         tmp &= ~S3C2410_IICCON_IRQPEND;
 421         writel(tmp, i2c->regs + S3C2410_IICCON);
 422  out:
 423         return ret;
 424 }
 425
 426 /* s3c24xx_i2c_irq
 427  *
 428  * top level IRQ servicing routine
 429 */
 430
 431 static irqreturn_t s3c24xx_i2c_irq(int irqno, void *dev_id)
 432 {
 433         struct s3c24xx_i2c *i2c = dev_id;
 434         unsigned long status;
 435         unsigned long tmp;
 436
 437         status = readl(i2c->regs + S3C2410_IICSTAT);
 438
 439         if (status & S3C2410_IICSTAT_ARBITR) {
 440                 /* deal with arbitration loss */
 441                 dev_err(i2c->dev, "deal with arbitration loss\n");
 442         }
 443
 444         if (i2c->state == STATE_IDLE) {
 445                 dev_dbg(i2c->dev, "IRQ: error i2c->state == IDLE\n");
 446
 447                 tmp = readl(i2c->regs + S3C2410_IICCON);
 448                 tmp &= ~S3C2410_IICCON_IRQPEND;
 449                 writel(tmp, i2c->regs +  S3C2410_IICCON);
 450                 goto out;
 451         }
 452
 453         /* pretty much this leaves us with the fact that we've
 454          * transmitted or received whatever byte we last sent */
 455
 456         i2c_s3c_irq_nextbyte(i2c, status);
 457
 458  out:
 459         return IRQ_HANDLED;
 460 }
 461
 462
 463 /* s3c24xx_i2c_set_master
 464  *
 465  * get the i2c bus for a master transaction
 466 */
 467
 468 static int s3c24xx_i2c_set_master(struct s3c24xx_i2c *i2c)
 469 {
 470         unsigned long iicstat;
 471         int timeout = 400;
 472
 473         while (timeout-- > 0) {
 474                 iicstat = readl(i2c->regs + S3C2410_IICSTAT);
 475
 476                 if (!(iicstat & S3C2410_IICSTAT_BUSBUSY))
 477                         return 0;
 478
 479                 msleep(1);
 480         }
 481
 482         return -ETIMEDOUT;
 483 }
 484
 485 /* s3c24xx_i2c_doxfer
 486  *
 487  * this starts an i2c transfer
 488 */
 489
 490 static int s3c24xx_i2c_doxfer(struct s3c24xx_i2c *i2c,
 491                               struct i2c_msg *msgs, int num)
 492 {
 493         unsigned long iicstat, timeout;
 494         int spins = 20;
 495         int ret;
 496
 497         if (i2c->suspended)
 498                 return -EIO;
 499
 500         ret = s3c24xx_i2c_set_master(i2c);
 501         if (ret != 0) {
 502                 dev_err(i2c->dev, "cannot get bus (error %d)\n", ret);
 503                 ret = -EAGAIN;
 504                 goto out;
 505         }
 506
 507         spin_lock_irq(&i2c->lock);
 508
 509         i2c->msg     = msgs;
 510         i2c->msg_num = num;
 511         i2c->msg_ptr = 0;
 512         i2c->msg_idx = 0;
 513         i2c->state   = STATE_START;
 514
 515         s3c24xx_i2c_enable_irq(i2c);
 516         s3c24xx_i2c_message_start(i2c, msgs);
 517         spin_unlock_irq(&i2c->lock);
 518
 519         timeout = wait_event_timeout(i2c->wait, i2c->msg_num == 0, HZ * 5);
 520
 521         ret = i2c->msg_idx;
 522
 523         /* having these next two as dev_err() makes life very
 524          * noisy when doing an i2cdetect */
 525
 526         if (timeout == 0)
 527                 dev_dbg(i2c->dev, "timeout\n");
 528         else if (ret != num)
 529                 dev_dbg(i2c->dev, "incomplete xfer (%d)\n", ret);
 530
 531         /* ensure the stop has been through the bus */
 532
 533         dev_dbg(i2c->dev, "waiting for bus idle\n");
 534
 535         /* first, try busy waiting briefly */
 536         do {
 537                 cpu_relax();
 538                 iicstat = readl(i2c->regs + S3C2410_IICSTAT);
 539         } while ((iicstat & S3C2410_IICSTAT_START) && --spins);
 540
 541         /* if that timed out sleep */
 542         if (!spins) {
 543                 msleep(1);
 544                 iicstat = readl(i2c->regs + S3C2410_IICSTAT);
 545         }
 546
 547         if (iicstat & S3C2410_IICSTAT_START)
 548                 dev_warn(i2c->dev, "timeout waiting for bus idle\n");
 549
 550  out:
 551         return ret;
 552 }
 553
 554 /* s3c24xx_i2c_xfer
 555  *
 556  * first port of call from the i2c bus code when an message needs
 557  * transferring across the i2c bus.
 558 */
 559
 560 static int s3c24xx_i2c_xfer(struct i2c_adapter *adap,
 561                         struct i2c_msg *msgs, int num)
 562 {
 563         struct s3c24xx_i2c *i2c = (struct s3c24xx_i2c *)adap->algo_data;
 564         int retry;
 565         int ret;
 566
 567         clk_enable(i2c->clk);
 568
 569         for (retry = 0; retry < adap->retries; retry++) {
 570
 571                 ret = s3c24xx_i2c_doxfer(i2c, msgs, num);
 572
 573                 if (ret != -EAGAIN) {
 574                         clk_disable(i2c->clk);
 575                         return ret;
 576                 }
 577
 578                 dev_dbg(i2c->dev, "Retrying transmission (%d)\n", retry);
 579
 580                 udelay(100);
 581         }
 582
 583         clk_disable(i2c->clk);
 584         return -EREMOTEIO;
 585 }
 586
 587 /* declare our i2c functionality */
 588 static u32 s3c24xx_i2c_func(struct i2c_adapter *adap)
 589 {
 590         return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_PROTOCOL_MANGLING;
 591 }
 592
 593 /* i2c bus registration info */
 594
 595 static const struct i2c_algorithm s3c24xx_i2c_algorithm = {
 596         .master_xfer            = s3c24xx_i2c_xfer,
 597         .functionality          = s3c24xx_i2c_func,
 598 };
 599
 600 /* s3c24xx_i2c_calcdivisor
 601  *
 602  * return the divisor settings for a given frequency
 603 */
 604
 605 static int s3c24xx_i2c_calcdivisor(unsigned long clkin, unsigned int wanted,
 606                                    unsigned int *div1, unsigned int *divs)
 607 {
 608         unsigned int calc_divs = clkin / wanted;
 609         unsigned int calc_div1;
 610
 611         if (calc_divs > (16*16))
 612                 calc_div1 = 512;
 613         else
 614                 calc_div1 = 16;
 615
 616         calc_divs += calc_div1-1;
 617         calc_divs /= calc_div1;
 618
 619         if (calc_divs == 0)
 620                 calc_divs = 1;
 621         if (calc_divs > 17)
 622                 calc_divs = 17;
 623
 624         *divs = calc_divs;
 625         *div1 = calc_div1;
 626
 627         return clkin / (calc_divs * calc_div1);
 628 }
 629
 630 /* s3c24xx_i2c_clockrate
 631  *
 632  * work out a divisor for the user requested frequency setting,
 633  * either by the requested frequency, or scanning the acceptable
 634  * range of frequencies until something is found
 635 */
 636
 637 static int s3c24xx_i2c_clockrate(struct s3c24xx_i2c *i2c, unsigned int *got)
 638 {
 639         struct s3c2410_platform_i2c *pdata = i2c->pdata;
 640         unsigned long clkin = clk_get_rate(i2c->clk);
 641         unsigned int divs, div1;
 642         unsigned long target_frequency;
 643         u32 iiccon;
 644         int freq;
 645
 646         i2c->clkrate = clkin;
 647         clkin /= 1000;          /* clkin now in KHz */
 648
 649         dev_dbg(i2c->dev, "pdata desired frequency %lu\n", pdata->frequency);
 650
 651         target_frequency = pdata->frequency ? pdata->frequency : 100000;
 652
 653         target_frequency /= 1000; /* Target frequency now in KHz */
 654
 655         freq = s3c24xx_i2c_calcdivisor(clkin, target_frequency, &div1, &divs);
 656
 657         if (freq > target_frequency) {
 658                 dev_err(i2c->dev,
 659                         "Unable to achieve desired frequency %luKHz."   \
 660                         " Lowest achievable %dKHz\n", target_frequency, freq);
 661                 return -EINVAL;
 662         }
 663
 664         *got = freq;
 665
 666         iiccon = readl(i2c->regs + S3C2410_IICCON);
 667         iiccon &= ~(S3C2410_IICCON_SCALEMASK | S3C2410_IICCON_TXDIV_512);
 668         iiccon |= (divs-1);
 669
 670         if (div1 == 512)
 671                 iiccon |= S3C2410_IICCON_TXDIV_512;
 672
 673         writel(iiccon, i2c->regs + S3C2410_IICCON);
 674
 675         if (s3c24xx_i2c_is2440(i2c)) {
 676                 unsigned long sda_delay;
 677
 678                 if (pdata->sda_delay) {
 679                         sda_delay = clkin * pdata->sda_delay;
 680                         sda_delay = DIV_ROUND_UP(sda_delay, 1000000);
 681                         sda_delay = DIV_ROUND_UP(sda_delay, 5);
 682                         if (sda_delay > 3)
 683                                 sda_delay = 3;
 684                         sda_delay |= S3C2410_IICLC_FILTER_ON;
 685                 } else
 686                         sda_delay = 0;
 687
 688                 dev_dbg(i2c->dev, "IICLC=%08lx\n", sda_delay);
 689                 writel(sda_delay, i2c->regs + S3C2440_IICLC);
 690         }
 691
 692         return 0;
 693 }
 694
 695 #ifdef CONFIG_CPU_FREQ
 696
 697 #define freq_to_i2c(_n) container_of(_n, struct s3c24xx_i2c, freq_transition)
 698
 699 static int s3c24xx_i2c_cpufreq_transition(struct notifier_block *nb,
 700                                           unsigned long val, void *data)
 701 {
 702         struct s3c24xx_i2c *i2c = freq_to_i2c(nb);
 703         unsigned long flags;
 704         unsigned int got;
 705         int delta_f;
 706         int ret;
 707
 708         delta_f = clk_get_rate(i2c->clk) - i2c->clkrate;
 709
 710         /* if we're post-change and the input clock has slowed down
 711          * or at pre-change and the clock is about to speed up, then
 712          * adjust our clock rate. <0 is slow, >0 speedup.
 713          */
 714
 715         if ((val == CPUFREQ_POSTCHANGE && delta_f < 0) ||
 716             (val == CPUFREQ_PRECHANGE && delta_f > 0)) {
 717                 spin_lock_irqsave(&i2c->lock, flags);
 718                 ret = s3c24xx_i2c_clockrate(i2c, &got);
 719                 spin_unlock_irqrestore(&i2c->lock, flags);
 720
 721                 if (ret < 0)
 722                         dev_err(i2c->dev, "cannot find frequency\n");
 723                 else
 724                         dev_info(i2c->dev, "setting freq %d\n", got);
 725         }
 726
 727         return 0;
 728 }
 729
 730 static inline int s3c24xx_i2c_register_cpufreq(struct s3c24xx_i2c *i2c)
 731 {
 732         i2c->freq_transition.notifier_call = s3c24xx_i2c_cpufreq_transition;
 733
 734         return cpufreq_register_notifier(&i2c->freq_transition,
 735                                          CPUFREQ_TRANSITION_NOTIFIER);
 736 }
 737
 738 static inline void s3c24xx_i2c_deregister_cpufreq(struct s3c24xx_i2c *i2c)
 739 {
 740         cpufreq_unregister_notifier(&i2c->freq_transition,
 741                                     CPUFREQ_TRANSITION_NOTIFIER);
 742 }
 743
 744 #else
 745 static inline int s3c24xx_i2c_register_cpufreq(struct s3c24xx_i2c *i2c)
 746 {
 747         return 0;
 748 }
 749
 750 static inline void s3c24xx_i2c_deregister_cpufreq(struct s3c24xx_i2c *i2c)
 751 {
 752 }
 753 #endif
 754
 755 #ifdef CONFIG_OF
 756 static int s3c24xx_i2c_parse_dt_gpio(struct s3c24xx_i2c *i2c)
 757 {
 758         int idx, gpio, ret;
 759
 760         for (idx = 0; idx < 2; idx++) {
 761                 gpio = of_get_gpio(i2c->dev->of_node, idx);
 762                 if (!gpio_is_valid(gpio)) {
 763                         dev_err(i2c->dev, "invalid gpio[%d]: %d\n", idx, gpio);
 764                         goto free_gpio;
 765                 }
 766
 767                 ret = gpio_request(gpio, "i2c-bus");
 768                 if (ret) {
 769                         dev_err(i2c->dev, "gpio [%d] request failed\n", gpio);
 770                         goto free_gpio;
 771                 }
 772         }
 773         return 0;
 774
 775 free_gpio:
 776         while (--idx >= 0)
 777                 gpio_free(i2c->gpios[idx]);
 778         return -EINVAL;
 779 }
 780
 781 static void s3c24xx_i2c_dt_gpio_free(struct s3c24xx_i2c *i2c)
 782 {
 783         unsigned int idx;
 784         for (idx = 0; idx < 2; idx++)
 785                 gpio_free(i2c->gpios[idx]);
 786 }
 787 #else
 788 static int s3c24xx_i2c_parse_dt_gpio(struct s3c24xx_i2c *i2c)
 789 {
 790         return 0;
 791 }
 792
 793 static void s3c24xx_i2c_dt_gpio_free(struct s3c24xx_i2c *i2c)
 794 {
 795 }
 796 #endif
 797
 798 /* s3c24xx_i2c_init
 799  *
 800  * initialise the controller, set the IO lines and frequency
 801 */
 802
 803 static int s3c24xx_i2c_init(struct s3c24xx_i2c *i2c)
 804 {
 805         unsigned long iicon = S3C2410_IICCON_IRQEN | S3C2410_IICCON_ACKEN;
 806         struct s3c2410_platform_i2c *pdata;
 807         unsigned int freq;
 808
 809         /* get the plafrom data */
 810
 811         pdata = i2c->pdata;
 812
 813         /* inititalise the gpio */
 814
 815         if (pdata->cfg_gpio)
 816                 pdata->cfg_gpio(to_platform_device(i2c->dev));
 817         else
 818                 if (s3c24xx_i2c_parse_dt_gpio(i2c))
 819                         return -EINVAL;
 820
 821         /* write slave address */
 822
 823         writeb(pdata->slave_addr, i2c->regs + S3C2410_IICADD);
 824
 825         dev_info(i2c->dev, "slave address 0x%02x\n", pdata->slave_addr);
 826
 827         writel(iicon, i2c->regs + S3C2410_IICCON);
 828
 829         /* we need to work out the divisors for the clock... */
 830
 831         if (s3c24xx_i2c_clockrate(i2c, &freq) != 0) {
 832                 writel(0, i2c->regs + S3C2410_IICCON);
 833                 dev_err(i2c->dev, "cannot meet bus frequency required\n");
 834                 return -EINVAL;
 835         }
 836
 837         /* todo - check that the i2c lines aren't being dragged anywhere */
 838
 839         dev_info(i2c->dev, "bus frequency set to %d KHz\n", freq);
 840         dev_dbg(i2c->dev, "S3C2410_IICCON=0x%02lx\n", iicon);
 841
 842         return 0;
 843 }
 844
 845 #ifdef CONFIG_OF
 846 /* s3c24xx_i2c_parse_dt
 847  *
 848  * Parse the device tree node and retreive the platform data.
 849 */
 850
 851 static void
 852 s3c24xx_i2c_parse_dt(struct device_node *np, struct s3c24xx_i2c *i2c)
 853 {
 854         struct s3c2410_platform_i2c *pdata = i2c->pdata;
 855
 856         if (!np)
 857                 return;
 858
 859         pdata->bus_num = -1; /* i2c bus number is dynamically assigned */
 860         of_property_read_u32(np, "samsung,i2c-sda-delay", &pdata->sda_delay);
 861         of_property_read_u32(np, "samsung,i2c-slave-addr", &pdata->slave_addr);
 862         of_property_read_u32(np, "samsung,i2c-max-bus-freq",
 863                                 (u32 *)&pdata->frequency);
 864 }
 865 #else
 866 static void
 867 s3c24xx_i2c_parse_dt(struct device_node *np, struct s3c24xx_i2c *i2c)
 868 {
 869         return;
 870 }
 871 #endif
 872
 873 /* s3c24xx_i2c_probe
 874  *
 875  * called by the bus driver when a suitable device is found
 876 */
 877
 878 static int s3c24xx_i2c_probe(struct platform_device *pdev)
 879 {
 880         struct s3c24xx_i2c *i2c;
 881         struct s3c2410_platform_i2c *pdata = NULL;
 882         struct resource *res;
 883         int ret;
 884
 885         if (!pdev->dev.of_node) {
 886                 pdata = pdev->dev.platform_data;
 887                 if (!pdata) {
 888                         dev_err(&pdev->dev, "no platform data\n");
 889                         return -EINVAL;
 890                 }
 891         }
 892
 893         i2c = kzalloc(sizeof(struct s3c24xx_i2c), GFP_KERNEL);
 894         if (!i2c) {
 895                 dev_err(&pdev->dev, "no memory for state\n");
 896                 return -ENOMEM;
 897         }
 898
 899         i2c->pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
 900         if (!i2c->pdata) {
 901                 ret = -ENOMEM;
 902                 goto err_noclk;
 903         }
 904
 905         if (pdata)
 906                 memcpy(i2c->pdata, pdata, sizeof(*pdata));
 907         else
 908                 s3c24xx_i2c_parse_dt(pdev->dev.of_node, i2c);
 909
 910         strlcpy(i2c->adap.name, "s3c2410-i2c", sizeof(i2c->adap.name));
 911         i2c->adap.owner   = THIS_MODULE;
 912         i2c->adap.algo    = &s3c24xx_i2c_algorithm;
 913         i2c->adap.retries = 2;
 914         i2c->adap.class   = I2C_CLASS_HWMON | I2C_CLASS_SPD;
 915         i2c->tx_setup     = 50;
 916
 917         spin_lock_init(&i2c->lock);
 918         init_waitqueue_head(&i2c->wait);
 919
 920         /* find the clock and enable it */
 921
 922         i2c->dev = &pdev->dev;
 923         i2c->clk = clk_get(&pdev->dev, "i2c");
 924         if (IS_ERR(i2c->clk)) {
 925                 dev_err(&pdev->dev, "cannot get clock\n");
 926                 ret = -ENOENT;
 927                 goto err_noclk;
 928         }
 929
 930         dev_dbg(&pdev->dev, "clock source %p\n", i2c->clk);
 931
 932         clk_enable(i2c->clk);
 933
 934         /* map the registers */
 935
 936         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 937         if (res == NULL) {
 938                 dev_err(&pdev->dev, "cannot find IO resource\n");
 939                 ret = -ENOENT;
 940                 goto err_clk;
 941         }
 942
 943         i2c->ioarea = request_mem_region(res->start, resource_size(res),
 944                                          pdev->name);
 945
 946         if (i2c->ioarea == NULL) {
 947                 dev_err(&pdev->dev, "cannot request IO\n");
 948                 ret = -ENXIO;
 949                 goto err_clk;
 950         }
 951
 952         i2c->regs = ioremap(res->start, resource_size(res));
 953
 954         if (i2c->regs == NULL) {
 955                 dev_err(&pdev->dev, "cannot map IO\n");
 956                 ret = -ENXIO;
 957                 goto err_ioarea;
 958         }
 959
 960         dev_dbg(&pdev->dev, "registers %p (%p, %p)\n",
 961                 i2c->regs, i2c->ioarea, res);
 962
 963         /* setup info block for the i2c core */
 964
 965         i2c->adap.algo_data = i2c;
 966         i2c->adap.dev.parent = &pdev->dev;
 967
 968         /* initialise the i2c controller */
 969
 970         ret = s3c24xx_i2c_init(i2c);
 971         if (ret != 0)
 972                 goto err_iomap;
 973
 974         /* find the IRQ for this unit (note, this relies on the init call to
 975          * ensure no current IRQs pending
 976          */
 977
 978         i2c->irq = ret = platform_get_irq(pdev, 0);
 979         if (ret <= 0) {
 980                 dev_err(&pdev->dev, "cannot find IRQ\n");
 981                 goto err_iomap;
 982         }
 983
 984         ret = request_irq(i2c->irq, s3c24xx_i2c_irq, 0,
 985                           dev_name(&pdev->dev), i2c);
 986
 987         if (ret != 0) {
 988                 dev_err(&pdev->dev, "cannot claim IRQ %d\n", i2c->irq);
 989                 goto err_iomap;
 990         }
 991
 992         ret = s3c24xx_i2c_register_cpufreq(i2c);
 993         if (ret < 0) {
 994                 dev_err(&pdev->dev, "failed to register cpufreq notifier\n");
 995                 goto err_irq;
 996         }
 997
 998         /* Note, previous versions of the driver used i2c_add_adapter()
 999          * to add the bus at any number. We now pass the bus number via
1000          * the platform data, so if unset it will now default to always
1001          * being bus 0.
1002          */
1003
1004         i2c->adap.nr = i2c->pdata->bus_num;
1005         i2c->adap.dev.of_node = pdev->dev.of_node;
1006
1007         ret = i2c_add_numbered_adapter(&i2c->adap);
1008         if (ret < 0) {
1009                 dev_err(&pdev->dev, "failed to add bus to i2c core\n");
1010                 goto err_cpufreq;
1011         }
1012
1013         of_i2c_register_devices(&i2c->adap);
1014         platform_set_drvdata(pdev, i2c);
1015
1016         dev_info(&pdev->dev, "%s: S3C I2C adapter\n", dev_name(&i2c->adap.dev));
1017         clk_disable(i2c->clk);
1018         return 0;
1019
1020  err_cpufreq:
1021         s3c24xx_i2c_deregister_cpufreq(i2c);
1022
1023  err_irq:
1024         free_irq(i2c->irq, i2c);
1025
1026  err_iomap:
1027         iounmap(i2c->regs);
1028
1029  err_ioarea:
1030         release_resource(i2c->ioarea);
1031         kfree(i2c->ioarea);
1032
1033  err_clk:
1034         clk_disable(i2c->clk);
1035         clk_put(i2c->clk);
1036
1037  err_noclk:
1038         kfree(i2c);
1039         return ret;
1040 }
1041
1042 /* s3c24xx_i2c_remove
1043  *
1044  * called when device is removed from the bus
1045 */
1046
1047 static int s3c24xx_i2c_remove(struct platform_device *pdev)
1048 {
1049         struct s3c24xx_i2c *i2c = platform_get_drvdata(pdev);
1050
1051         s3c24xx_i2c_deregister_cpufreq(i2c);
1052
1053         i2c_del_adapter(&i2c->adap);
1054         free_irq(i2c->irq, i2c);
1055
1056         clk_disable(i2c->clk);
1057         clk_put(i2c->clk);
1058
1059         iounmap(i2c->regs);
1060
1061         release_resource(i2c->ioarea);
1062         s3c24xx_i2c_dt_gpio_free(i2c);
1063         kfree(i2c->ioarea);
1064         kfree(i2c);
1065
1066         return 0;
1067 }
1068
1069 #ifdef CONFIG_PM
1070 static int s3c24xx_i2c_suspend_noirq(struct device *dev)
1071 {
1072         struct platform_device *pdev = to_platform_device(dev);
1073         struct s3c24xx_i2c *i2c = platform_get_drvdata(pdev);
1074
1075         i2c->suspended = 1;
1076
1077         return 0;
1078 }
1079
1080 static int s3c24xx_i2c_resume(struct device *dev)
1081 {
1082         struct platform_device *pdev = to_platform_device(dev);
1083         struct s3c24xx_i2c *i2c = platform_get_drvdata(pdev);
1084
1085         i2c->suspended = 0;
1086         clk_enable(i2c->clk);
1087         s3c24xx_i2c_init(i2c);
1088         clk_disable(i2c->clk);
1089
1090         return 0;
1091 }
1092
1093 static const struct dev_pm_ops s3c24xx_i2c_dev_pm_ops = {
1094         .suspend_noirq = s3c24xx_i2c_suspend_noirq,
1095         .resume = s3c24xx_i2c_resume,
1096 };
1097
1098 #define S3C24XX_DEV_PM_OPS (&s3c24xx_i2c_dev_pm_ops)
1099 #else
1100 #define S3C24XX_DEV_PM_OPS NULL
1101 #endif
1102
1103 /* device driver for platform bus bits */
1104
1105 static struct platform_device_id s3c24xx_driver_ids[] = {
1106         {
1107                 .name           = "s3c2410-i2c",
1108                 .driver_data    = TYPE_S3C2410,
1109         }, {
1110                 .name           = "s3c2440-i2c",
1111                 .driver_data    = TYPE_S3C2440,
1112         }, { },
1113 };
1114 MODULE_DEVICE_TABLE(platform, s3c24xx_driver_ids);
1115
1116 #ifdef CONFIG_OF
1117 static const struct of_device_id s3c24xx_i2c_match[] = {
1118         { .compatible = "samsung,s3c2410-i2c" },
1119         { .compatible = "samsung,s3c2440-i2c" },
1120         {},
1121 };
1122 MODULE_DEVICE_TABLE(of, s3c24xx_i2c_match);
1123 #else
1124 #define s3c24xx_i2c_match NULL
1125 #endif
1126
1127 static struct platform_driver s3c24xx_i2c_driver = {
1128         .probe          = s3c24xx_i2c_probe,
1129         .remove         = s3c24xx_i2c_remove,
1130         .id_table       = s3c24xx_driver_ids,
1131         .driver         = {
1132                 .owner  = THIS_MODULE,
1133                 .name   = "s3c-i2c",
1134                 .pm     = S3C24XX_DEV_PM_OPS,
1135                 .of_match_table = s3c24xx_i2c_match,
1136         },
1137 };
1138
1139 static int __init i2c_adap_s3c_init(void)
1140 {
1141         return platform_driver_register(&s3c24xx_i2c_driver);
1142 }
1143 subsys_initcall(i2c_adap_s3c_init);
1144
1145 static void __exit i2c_adap_s3c_exit(void)
1146 {
1147         platform_driver_unregister(&s3c24xx_i2c_driver);
1148 }
1149 module_exit(i2c_adap_s3c_exit);
1150
1151 MODULE_DESCRIPTION("S3C24XX I2C Bus driver");
1152 MODULE_AUTHOR("Ben Dooks, <ben@simtec.co.uk>");
1153 MODULE_LICENSE("GPL");