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/pm_runtime.h>
  35 #include <linux/clk.h>
  36 #include <linux/cpufreq.h>
  37 #include <linux/slab.h>
  38 #include <linux/io.h>
  39 #include <linux/of_i2c.h>
  40 #include <linux/of_gpio.h>
  41 #include <linux/pinctrl/consumer.h>
  42
  43 #include <asm/irq.h>
  44
  45 #include <plat/regs-iic.h>
  46 #include <linux/platform_data/i2c-s3c2410.h>
  47
  48 /* Treat S3C2410 as baseline hardware, anything else is supported via quirks */
  49 #define QUIRK_S3C2440           (1 << 0)
  50 #define QUIRK_HDMIPHY           (1 << 1)
  51 #define QUIRK_NO_GPIO           (1 << 2)
  52
  53 /* i2c controller state */
  54 enum s3c24xx_i2c_state {
  55         STATE_IDLE,
  56         STATE_START,
  57         STATE_READ,
  58         STATE_WRITE,
  59         STATE_STOP
  60 };
  61
  62 struct s3c24xx_i2c {
  63         wait_queue_head_t       wait;
  64         unsigned int            quirks;
  65         unsigned int            suspended:1;
  66
  67         struct i2c_msg          *msg;
  68         unsigned int            msg_num;
  69         unsigned int            msg_idx;
  70         unsigned int            msg_ptr;
  71
  72         unsigned int            tx_setup;
  73         unsigned int            irq;
  74
  75         enum s3c24xx_i2c_state  state;
  76         unsigned long           clkrate;
  77
  78         void __iomem            *regs;
  79         struct clk              *clk;
  80         struct device           *dev;
  81         struct i2c_adapter      adap;
  82
  83         struct s3c2410_platform_i2c     *pdata;
  84         int                     gpios[2];
  85         struct pinctrl          *pctrl;
  86 #ifdef CONFIG_CPU_FREQ
  87         struct notifier_block   freq_transition;
  88 #endif
  89 };
  90
  91 static struct platform_device_id s3c24xx_driver_ids[] = {
  92         {
  93                 .name           = "s3c2410-i2c",
  94                 .driver_data    = 0,
  95         }, {
  96                 .name           = "s3c2440-i2c",
  97                 .driver_data    = QUIRK_S3C2440,
  98         }, {
  99                 .name           = "s3c2440-hdmiphy-i2c",
 100                 .driver_data    = QUIRK_S3C2440 | QUIRK_HDMIPHY | QUIRK_NO_GPIO,
 101         }, { },
 102 };
 103 MODULE_DEVICE_TABLE(platform, s3c24xx_driver_ids);
 104
 105 #ifdef CONFIG_OF
 106 static const struct of_device_id s3c24xx_i2c_match[] = {
 107         { .compatible = "samsung,s3c2410-i2c", .data = (void *)0 },
 108         { .compatible = "samsung,s3c2440-i2c", .data = (void *)QUIRK_S3C2440 },
 109         { .compatible = "samsung,s3c2440-hdmiphy-i2c",
 110           .data = (void *)(QUIRK_S3C2440 | QUIRK_HDMIPHY | QUIRK_NO_GPIO) },
 111         {},
 112 };
 113 MODULE_DEVICE_TABLE(of, s3c24xx_i2c_match);
 114 #endif
 115
 116 /* s3c24xx_get_device_quirks
 117  *
 118  * Get controller type either from device tree or platform device variant.
 119 */
 120
 121 static inline unsigned int s3c24xx_get_device_quirks(struct platform_device *pdev)
 122 {
 123         if (pdev->dev.of_node) {
 124                 const struct of_device_id *match;
 125                 match = of_match_node(s3c24xx_i2c_match, pdev->dev.of_node);
 126                 return (unsigned int)match->data;
 127         }
 128
 129         return platform_get_device_id(pdev)->driver_data;
 130 }
 131
 132 /* s3c24xx_i2c_master_complete
 133  *
 134  * complete the message and wake up the caller, using the given return code,
 135  * or zero to mean ok.
 136 */
 137
 138 static inline void s3c24xx_i2c_master_complete(struct s3c24xx_i2c *i2c, int ret)
 139 {
 140         dev_dbg(i2c->dev, "master_complete %d\n", ret);
 141
 142         i2c->msg_ptr = 0;
 143         i2c->msg = NULL;
 144         i2c->msg_idx++;
 145         i2c->msg_num = 0;
 146         if (ret)
 147                 i2c->msg_idx = ret;
 148
 149         wake_up(&i2c->wait);
 150 }
 151
 152 static inline void s3c24xx_i2c_disable_ack(struct s3c24xx_i2c *i2c)
 153 {
 154         unsigned long tmp;
 155
 156         tmp = readl(i2c->regs + S3C2410_IICCON);
 157         writel(tmp & ~S3C2410_IICCON_ACKEN, i2c->regs + S3C2410_IICCON);
 158 }
 159
 160 static inline void s3c24xx_i2c_enable_ack(struct s3c24xx_i2c *i2c)
 161 {
 162         unsigned long tmp;
 163
 164         tmp = readl(i2c->regs + S3C2410_IICCON);
 165         writel(tmp | S3C2410_IICCON_ACKEN, i2c->regs + S3C2410_IICCON);
 166 }
 167
 168 /* irq enable/disable functions */
 169
 170 static inline void s3c24xx_i2c_disable_irq(struct s3c24xx_i2c *i2c)
 171 {
 172         unsigned long tmp;
 173
 174         tmp = readl(i2c->regs + S3C2410_IICCON);
 175         writel(tmp & ~S3C2410_IICCON_IRQEN, i2c->regs + S3C2410_IICCON);
 176 }
 177
 178 static inline void s3c24xx_i2c_enable_irq(struct s3c24xx_i2c *i2c)
 179 {
 180         unsigned long tmp;
 181
 182         tmp = readl(i2c->regs + S3C2410_IICCON);
 183         writel(tmp | S3C2410_IICCON_IRQEN, i2c->regs + S3C2410_IICCON);
 184 }
 185
 186
 187 /* s3c24xx_i2c_message_start
 188  *
 189  * put the start of a message onto the bus
 190 */
 191
 192 static void s3c24xx_i2c_message_start(struct s3c24xx_i2c *i2c,
 193                                       struct i2c_msg *msg)
 194 {
 195         unsigned int addr = (msg->addr & 0x7f) << 1;
 196         unsigned long stat;
 197         unsigned long iiccon;
 198
 199         stat = 0;
 200         stat |=  S3C2410_IICSTAT_TXRXEN;
 201
 202         if (msg->flags & I2C_M_RD) {
 203                 stat |= S3C2410_IICSTAT_MASTER_RX;
 204                 addr |= 1;
 205         } else
 206                 stat |= S3C2410_IICSTAT_MASTER_TX;
 207
 208         if (msg->flags & I2C_M_REV_DIR_ADDR)
 209                 addr ^= 1;
 210
 211         /* todo - check for wether ack wanted or not */
 212         s3c24xx_i2c_enable_ack(i2c);
 213
 214         iiccon = readl(i2c->regs + S3C2410_IICCON);
 215         writel(stat, i2c->regs + S3C2410_IICSTAT);
 216
 217         dev_dbg(i2c->dev, "START: %08lx to IICSTAT, %02x to DS\n", stat, addr);
 218         writeb(addr, i2c->regs + S3C2410_IICDS);
 219
 220         /* delay here to ensure the data byte has gotten onto the bus
 221          * before the transaction is started */
 222
 223         ndelay(i2c->tx_setup);
 224
 225         dev_dbg(i2c->dev, "iiccon, %08lx\n", iiccon);
 226         writel(iiccon, i2c->regs + S3C2410_IICCON);
 227
 228         stat |= S3C2410_IICSTAT_START;
 229         writel(stat, i2c->regs + S3C2410_IICSTAT);
 230 }
 231
 232 static inline void s3c24xx_i2c_stop(struct s3c24xx_i2c *i2c, int ret)
 233 {
 234         unsigned long iicstat = readl(i2c->regs + S3C2410_IICSTAT);
 235
 236         dev_dbg(i2c->dev, "STOP\n");
 237
 238         /* stop the transfer */
 239         iicstat &= ~S3C2410_IICSTAT_START;
 240         writel(iicstat, i2c->regs + S3C2410_IICSTAT);
 241
 242         i2c->state = STATE_STOP;
 243
 244         s3c24xx_i2c_master_complete(i2c, ret);
 245         s3c24xx_i2c_disable_irq(i2c);
 246 }
 247
 248 /* helper functions to determine the current state in the set of
 249  * messages we are sending */
 250
 251 /* is_lastmsg()
 252  *
 253  * returns TRUE if the current message is the last in the set
 254 */
 255
 256 static inline int is_lastmsg(struct s3c24xx_i2c *i2c)
 257 {
 258         return i2c->msg_idx >= (i2c->msg_num - 1);
 259 }
 260
 261 /* is_msglast
 262  *
 263  * returns TRUE if we this is the last byte in the current message
 264 */
 265
 266 static inline int is_msglast(struct s3c24xx_i2c *i2c)
 267 {
 268         return i2c->msg_ptr == i2c->msg->len-1;
 269 }
 270
 271 /* is_msgend
 272  *
 273  * returns TRUE if we reached the end of the current message
 274 */
 275
 276 static inline int is_msgend(struct s3c24xx_i2c *i2c)
 277 {
 278         return i2c->msg_ptr >= i2c->msg->len;
 279 }
 280
 281 /* i2c_s3c_irq_nextbyte
 282  *
 283  * process an interrupt and work out what to do
 284  */
 285
 286 static int i2c_s3c_irq_nextbyte(struct s3c24xx_i2c *i2c, unsigned long iicstat)
 287 {
 288         unsigned long tmp;
 289         unsigned char byte;
 290         int ret = 0;
 291
 292         switch (i2c->state) {
 293
 294         case STATE_IDLE:
 295                 dev_err(i2c->dev, "%s: called in STATE_IDLE\n", __func__);
 296                 goto out;
 297
 298         case STATE_STOP:
 299                 dev_err(i2c->dev, "%s: called in STATE_STOP\n", __func__);
 300                 s3c24xx_i2c_disable_irq(i2c);
 301                 goto out_ack;
 302
 303         case STATE_START:
 304                 /* last thing we did was send a start condition on the
 305                  * bus, or started a new i2c message
 306                  */
 307
 308                 if (iicstat & S3C2410_IICSTAT_LASTBIT &&
 309                     !(i2c->msg->flags & I2C_M_IGNORE_NAK)) {
 310                         /* ack was not received... */
 311
 312                         dev_dbg(i2c->dev, "ack was not received\n");
 313                         s3c24xx_i2c_stop(i2c, -ENXIO);
 314                         goto out_ack;
 315                 }
 316
 317                 if (i2c->msg->flags & I2C_M_RD)
 318                         i2c->state = STATE_READ;
 319                 else
 320                         i2c->state = STATE_WRITE;
 321
 322                 /* terminate the transfer if there is nothing to do
 323                  * as this is used by the i2c probe to find devices. */
 324
 325                 if (is_lastmsg(i2c) && i2c->msg->len == 0) {
 326                         s3c24xx_i2c_stop(i2c, 0);
 327                         goto out_ack;
 328                 }
 329
 330                 if (i2c->state == STATE_READ)
 331                         goto prepare_read;
 332
 333                 /* fall through to the write state, as we will need to
 334                  * send a byte as well */
 335
 336         case STATE_WRITE:
 337                 /* we are writing data to the device... check for the
 338                  * end of the message, and if so, work out what to do
 339                  */
 340
 341                 if (!(i2c->msg->flags & I2C_M_IGNORE_NAK)) {
 342                         if (iicstat & S3C2410_IICSTAT_LASTBIT) {
 343                                 dev_dbg(i2c->dev, "WRITE: No Ack\n");
 344
 345                                 s3c24xx_i2c_stop(i2c, -ECONNREFUSED);
 346                                 goto out_ack;
 347                         }
 348                 }
 349
 350  retry_write:
 351
 352                 if (!is_msgend(i2c)) {
 353                         byte = i2c->msg->buf[i2c->msg_ptr++];
 354                         writeb(byte, i2c->regs + S3C2410_IICDS);
 355
 356                         /* delay after writing the byte to allow the
 357                          * data setup time on the bus, as writing the
 358                          * data to the register causes the first bit
 359                          * to appear on SDA, and SCL will change as
 360                          * soon as the interrupt is acknowledged */
 361
 362                         ndelay(i2c->tx_setup);
 363
 364                 } else if (!is_lastmsg(i2c)) {
 365                         /* we need to go to the next i2c message */
 366
 367                         dev_dbg(i2c->dev, "WRITE: Next Message\n");
 368
 369                         i2c->msg_ptr = 0;
 370                         i2c->msg_idx++;
 371                         i2c->msg++;
 372
 373                         /* check to see if we need to do another message */
 374                         if (i2c->msg->flags & I2C_M_NOSTART) {
 375
 376                                 if (i2c->msg->flags & I2C_M_RD) {
 377                                         /* cannot do this, the controller
 378                                          * forces us to send a new START
 379                                          * when we change direction */
 380
 381                                         s3c24xx_i2c_stop(i2c, -EINVAL);
 382                                 }
 383
 384                                 goto retry_write;
 385                         } else {
 386                                 /* send the new start */
 387                                 s3c24xx_i2c_message_start(i2c, i2c->msg);
 388                                 i2c->state = STATE_START;
 389                         }
 390
 391                 } else {
 392                         /* send stop */
 393
 394                         s3c24xx_i2c_stop(i2c, 0);
 395                 }
 396                 break;
 397
 398         case STATE_READ:
 399                 /* we have a byte of data in the data register, do
 400                  * something with it, and then work out wether we are
 401                  * going to do any more read/write
 402                  */
 403
 404                 byte = readb(i2c->regs + S3C2410_IICDS);
 405                 i2c->msg->buf[i2c->msg_ptr++] = byte;
 406
 407  prepare_read:
 408                 if (is_msglast(i2c)) {
 409                         /* last byte of buffer */
 410
 411                         if (is_lastmsg(i2c))
 412                                 s3c24xx_i2c_disable_ack(i2c);
 413
 414                 } else if (is_msgend(i2c)) {
 415                         /* ok, we've read the entire buffer, see if there
 416                          * is anything else we need to do */
 417
 418                         if (is_lastmsg(i2c)) {
 419                                 /* last message, send stop and complete */
 420                                 dev_dbg(i2c->dev, "READ: Send Stop\n");
 421
 422                                 s3c24xx_i2c_stop(i2c, 0);
 423                         } else {
 424                                 /* go to the next transfer */
 425                                 dev_dbg(i2c->dev, "READ: Next Transfer\n");
 426
 427                                 i2c->msg_ptr = 0;
 428                                 i2c->msg_idx++;
 429                                 i2c->msg++;
 430                         }
 431                 }
 432
 433                 break;
 434         }
 435
 436         /* acknowlegde the IRQ and get back on with the work */
 437
 438  out_ack:
 439         tmp = readl(i2c->regs + S3C2410_IICCON);
 440         tmp &= ~S3C2410_IICCON_IRQPEND;
 441         writel(tmp, i2c->regs + S3C2410_IICCON);
 442  out:
 443         return ret;
 444 }
 445
 446 /* s3c24xx_i2c_irq
 447  *
 448  * top level IRQ servicing routine
 449 */
 450
 451 static irqreturn_t s3c24xx_i2c_irq(int irqno, void *dev_id)
 452 {
 453         struct s3c24xx_i2c *i2c = dev_id;
 454         unsigned long status;
 455         unsigned long tmp;
 456
 457         status = readl(i2c->regs + S3C2410_IICSTAT);
 458
 459         if (status & S3C2410_IICSTAT_ARBITR) {
 460                 /* deal with arbitration loss */
 461                 dev_err(i2c->dev, "deal with arbitration loss\n");
 462         }
 463
 464         if (i2c->state == STATE_IDLE) {
 465                 dev_dbg(i2c->dev, "IRQ: error i2c->state == IDLE\n");
 466
 467                 tmp = readl(i2c->regs + S3C2410_IICCON);
 468                 tmp &= ~S3C2410_IICCON_IRQPEND;
 469                 writel(tmp, i2c->regs +  S3C2410_IICCON);
 470                 goto out;
 471         }
 472
 473         /* pretty much this leaves us with the fact that we've
 474          * transmitted or received whatever byte we last sent */
 475
 476         i2c_s3c_irq_nextbyte(i2c, status);
 477
 478  out:
 479         return IRQ_HANDLED;
 480 }
 481
 482
 483 /* s3c24xx_i2c_set_master
 484  *
 485  * get the i2c bus for a master transaction
 486 */
 487
 488 static int s3c24xx_i2c_set_master(struct s3c24xx_i2c *i2c)
 489 {
 490         unsigned long iicstat;
 491         int timeout = 400;
 492
 493         /* the timeout for HDMIPHY is reduced to 10 ms because
 494          * the hangup is expected to happen, so waiting 400 ms
 495          * causes only unnecessary system hangup
 496          */
 497         if (i2c->quirks & QUIRK_HDMIPHY)
 498                 timeout = 10;
 499
 500         while (timeout-- > 0) {
 501                 iicstat = readl(i2c->regs + S3C2410_IICSTAT);
 502
 503                 if (!(iicstat & S3C2410_IICSTAT_BUSBUSY))
 504                         return 0;
 505
 506                 msleep(1);
 507         }
 508
 509         /* hang-up of bus dedicated for HDMIPHY occurred, resetting */
 510         if (i2c->quirks & QUIRK_HDMIPHY) {
 511                 writel(0, i2c->regs + S3C2410_IICCON);
 512                 writel(0, i2c->regs + S3C2410_IICSTAT);
 513                 writel(0, i2c->regs + S3C2410_IICDS);
 514
 515                 return 0;
 516         }
 517
 518         return -ETIMEDOUT;
 519 }
 520
 521 /* s3c24xx_i2c_doxfer
 522  *
 523  * this starts an i2c transfer
 524 */
 525
 526 static int s3c24xx_i2c_doxfer(struct s3c24xx_i2c *i2c,
 527                               struct i2c_msg *msgs, int num)
 528 {
 529         unsigned long iicstat, timeout;
 530         int spins = 20;
 531         int ret;
 532
 533         if (i2c->suspended)
 534                 return -EIO;
 535
 536         ret = s3c24xx_i2c_set_master(i2c);
 537         if (ret != 0) {
 538                 dev_err(i2c->dev, "cannot get bus (error %d)\n", ret);
 539                 ret = -EAGAIN;
 540                 goto out;
 541         }
 542
 543         i2c->msg     = msgs;
 544         i2c->msg_num = num;
 545         i2c->msg_ptr = 0;
 546         i2c->msg_idx = 0;
 547         i2c->state   = STATE_START;
 548
 549         s3c24xx_i2c_enable_irq(i2c);
 550         s3c24xx_i2c_message_start(i2c, msgs);
 551
 552         timeout = wait_event_timeout(i2c->wait, i2c->msg_num == 0, HZ * 5);
 553
 554         ret = i2c->msg_idx;
 555
 556         /* having these next two as dev_err() makes life very
 557          * noisy when doing an i2cdetect */
 558
 559         if (timeout == 0)
 560                 dev_dbg(i2c->dev, "timeout\n");
 561         else if (ret != num)
 562                 dev_dbg(i2c->dev, "incomplete xfer (%d)\n", ret);
 563
 564         /* ensure the stop has been through the bus */
 565
 566         dev_dbg(i2c->dev, "waiting for bus idle\n");
 567
 568         /* first, try busy waiting briefly */
 569         do {
 570                 cpu_relax();
 571                 iicstat = readl(i2c->regs + S3C2410_IICSTAT);
 572         } while ((iicstat & S3C2410_IICSTAT_START) && --spins);
 573
 574         /* if that timed out sleep */
 575         if (!spins) {
 576                 msleep(1);
 577                 iicstat = readl(i2c->regs + S3C2410_IICSTAT);
 578         }
 579
 580         if (iicstat & S3C2410_IICSTAT_START)
 581                 dev_warn(i2c->dev, "timeout waiting for bus idle\n");
 582
 583  out:
 584         return ret;
 585 }
 586
 587 /* s3c24xx_i2c_xfer
 588  *
 589  * first port of call from the i2c bus code when an message needs
 590  * transferring across the i2c bus.
 591 */
 592
 593 static int s3c24xx_i2c_xfer(struct i2c_adapter *adap,
 594                         struct i2c_msg *msgs, int num)
 595 {
 596         struct s3c24xx_i2c *i2c = (struct s3c24xx_i2c *)adap->algo_data;
 597         int retry;
 598         int ret;
 599
 600         pm_runtime_get_sync(&adap->dev);
 601         clk_prepare_enable(i2c->clk);
 602
 603         for (retry = 0; retry < adap->retries; retry++) {
 604
 605                 ret = s3c24xx_i2c_doxfer(i2c, msgs, num);
 606
 607                 if (ret != -EAGAIN) {
 608                         clk_disable_unprepare(i2c->clk);
 609                         pm_runtime_put(&adap->dev);
 610                         return ret;
 611                 }
 612
 613                 dev_dbg(i2c->dev, "Retrying transmission (%d)\n", retry);
 614
 615                 udelay(100);
 616         }
 617
 618         clk_disable_unprepare(i2c->clk);
 619         pm_runtime_put(&adap->dev);
 620         return -EREMOTEIO;
 621 }
 622
 623 /* declare our i2c functionality */
 624 static u32 s3c24xx_i2c_func(struct i2c_adapter *adap)
 625 {
 626         return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_NOSTART |
 627                 I2C_FUNC_PROTOCOL_MANGLING;
 628 }
 629
 630 /* i2c bus registration info */
 631
 632 static const struct i2c_algorithm s3c24xx_i2c_algorithm = {
 633         .master_xfer            = s3c24xx_i2c_xfer,
 634         .functionality          = s3c24xx_i2c_func,
 635 };
 636
 637 /* s3c24xx_i2c_calcdivisor
 638  *
 639  * return the divisor settings for a given frequency
 640 */
 641
 642 static int s3c24xx_i2c_calcdivisor(unsigned long clkin, unsigned int wanted,
 643                                    unsigned int *div1, unsigned int *divs)
 644 {
 645         unsigned int calc_divs = clkin / wanted;
 646         unsigned int calc_div1;
 647
 648         if (calc_divs > (16*16))
 649                 calc_div1 = 512;
 650         else
 651                 calc_div1 = 16;
 652
 653         calc_divs += calc_div1-1;
 654         calc_divs /= calc_div1;
 655
 656         if (calc_divs == 0)
 657                 calc_divs = 1;
 658         if (calc_divs > 17)
 659                 calc_divs = 17;
 660
 661         *divs = calc_divs;
 662         *div1 = calc_div1;
 663
 664         return clkin / (calc_divs * calc_div1);
 665 }
 666
 667 /* s3c24xx_i2c_clockrate
 668  *
 669  * work out a divisor for the user requested frequency setting,
 670  * either by the requested frequency, or scanning the acceptable
 671  * range of frequencies until something is found
 672 */
 673
 674 static int s3c24xx_i2c_clockrate(struct s3c24xx_i2c *i2c, unsigned int *got)
 675 {
 676         struct s3c2410_platform_i2c *pdata = i2c->pdata;
 677         unsigned long clkin = clk_get_rate(i2c->clk);
 678         unsigned int divs, div1;
 679         unsigned long target_frequency;
 680         u32 iiccon;
 681         int freq;
 682
 683         i2c->clkrate = clkin;
 684         clkin /= 1000;          /* clkin now in KHz */
 685
 686         dev_dbg(i2c->dev, "pdata desired frequency %lu\n", pdata->frequency);
 687
 688         target_frequency = pdata->frequency ? pdata->frequency : 100000;
 689
 690         target_frequency /= 1000; /* Target frequency now in KHz */
 691
 692         freq = s3c24xx_i2c_calcdivisor(clkin, target_frequency, &div1, &divs);
 693
 694         if (freq > target_frequency) {
 695                 dev_err(i2c->dev,
 696                         "Unable to achieve desired frequency %luKHz."   \
 697                         " Lowest achievable %dKHz\n", target_frequency, freq);
 698                 return -EINVAL;
 699         }
 700
 701         *got = freq;
 702
 703         iiccon = readl(i2c->regs + S3C2410_IICCON);
 704         iiccon &= ~(S3C2410_IICCON_SCALEMASK | S3C2410_IICCON_TXDIV_512);
 705         iiccon |= (divs-1);
 706
 707         if (div1 == 512)
 708                 iiccon |= S3C2410_IICCON_TXDIV_512;
 709
 710         writel(iiccon, i2c->regs + S3C2410_IICCON);
 711
 712         if (i2c->quirks & QUIRK_S3C2440) {
 713                 unsigned long sda_delay;
 714
 715                 if (pdata->sda_delay) {
 716                         sda_delay = clkin * pdata->sda_delay;
 717                         sda_delay = DIV_ROUND_UP(sda_delay, 1000000);
 718                         sda_delay = DIV_ROUND_UP(sda_delay, 5);
 719                         if (sda_delay > 3)
 720                                 sda_delay = 3;
 721                         sda_delay |= S3C2410_IICLC_FILTER_ON;
 722                 } else
 723                         sda_delay = 0;
 724
 725                 dev_dbg(i2c->dev, "IICLC=%08lx\n", sda_delay);
 726                 writel(sda_delay, i2c->regs + S3C2440_IICLC);
 727         }
 728
 729         return 0;
 730 }
 731
 732 #ifdef CONFIG_CPU_FREQ
 733
 734 #define freq_to_i2c(_n) container_of(_n, struct s3c24xx_i2c, freq_transition)
 735
 736 static int s3c24xx_i2c_cpufreq_transition(struct notifier_block *nb,
 737                                           unsigned long val, void *data)
 738 {
 739         struct s3c24xx_i2c *i2c = freq_to_i2c(nb);
 740         unsigned int got;
 741         int delta_f;
 742         int ret;
 743
 744         delta_f = clk_get_rate(i2c->clk) - i2c->clkrate;
 745
 746         /* if we're post-change and the input clock has slowed down
 747          * or at pre-change and the clock is about to speed up, then
 748          * adjust our clock rate. <0 is slow, >0 speedup.
 749          */
 750
 751         if ((val == CPUFREQ_POSTCHANGE && delta_f < 0) ||
 752             (val == CPUFREQ_PRECHANGE && delta_f > 0)) {
 753                 i2c_lock_adapter(&i2c->adap);
 754                 ret = s3c24xx_i2c_clockrate(i2c, &got);
 755                 i2c_unlock_adapter(&i2c->adap);
 756
 757                 if (ret < 0)
 758                         dev_err(i2c->dev, "cannot find frequency\n");
 759                 else
 760                         dev_info(i2c->dev, "setting freq %d\n", got);
 761         }
 762
 763         return 0;
 764 }
 765
 766 static inline int s3c24xx_i2c_register_cpufreq(struct s3c24xx_i2c *i2c)
 767 {
 768         i2c->freq_transition.notifier_call = s3c24xx_i2c_cpufreq_transition;
 769
 770         return cpufreq_register_notifier(&i2c->freq_transition,
 771                                          CPUFREQ_TRANSITION_NOTIFIER);
 772 }
 773
 774 static inline void s3c24xx_i2c_deregister_cpufreq(struct s3c24xx_i2c *i2c)
 775 {
 776         cpufreq_unregister_notifier(&i2c->freq_transition,
 777                                     CPUFREQ_TRANSITION_NOTIFIER);
 778 }
 779
 780 #else
 781 static inline int s3c24xx_i2c_register_cpufreq(struct s3c24xx_i2c *i2c)
 782 {
 783         return 0;
 784 }
 785
 786 static inline void s3c24xx_i2c_deregister_cpufreq(struct s3c24xx_i2c *i2c)
 787 {
 788 }
 789 #endif
 790
 791 #ifdef CONFIG_OF
 792 static int s3c24xx_i2c_parse_dt_gpio(struct s3c24xx_i2c *i2c)
 793 {
 794         int idx, gpio, ret;
 795
 796         if (i2c->quirks & QUIRK_NO_GPIO)
 797                 return 0;
 798
 799         for (idx = 0; idx < 2; idx++) {
 800                 gpio = of_get_gpio(i2c->dev->of_node, idx);
 801                 if (!gpio_is_valid(gpio)) {
 802                         dev_err(i2c->dev, "invalid gpio[%d]: %d\n", idx, gpio);
 803                         goto free_gpio;
 804                 }
 805
 806                 ret = gpio_request(gpio, "i2c-bus");
 807                 if (ret) {
 808                         dev_err(i2c->dev, "gpio [%d] request failed\n", gpio);
 809                         goto free_gpio;
 810                 }
 811         }
 812         return 0;
 813
 814 free_gpio:
 815         while (--idx >= 0)
 816                 gpio_free(i2c->gpios[idx]);
 817         return -EINVAL;
 818 }
 819
 820 static void s3c24xx_i2c_dt_gpio_free(struct s3c24xx_i2c *i2c)
 821 {
 822         unsigned int idx;
 823
 824         if (i2c->quirks & QUIRK_NO_GPIO)
 825                 return;
 826
 827         for (idx = 0; idx < 2; idx++)
 828                 gpio_free(i2c->gpios[idx]);
 829 }
 830 #else
 831 static int s3c24xx_i2c_parse_dt_gpio(struct s3c24xx_i2c *i2c)
 832 {
 833         return 0;
 834 }
 835
 836 static void s3c24xx_i2c_dt_gpio_free(struct s3c24xx_i2c *i2c)
 837 {
 838 }
 839 #endif
 840
 841 /* s3c24xx_i2c_init
 842  *
 843  * initialise the controller, set the IO lines and frequency
 844 */
 845
 846 static int s3c24xx_i2c_init(struct s3c24xx_i2c *i2c)
 847 {
 848         unsigned long iicon = S3C2410_IICCON_IRQEN | S3C2410_IICCON_ACKEN;
 849         struct s3c2410_platform_i2c *pdata;
 850         unsigned int freq;
 851
 852         /* get the plafrom data */
 853
 854         pdata = i2c->pdata;
 855
 856         /* inititalise the gpio */
 857
 858         if (pdata->cfg_gpio)
 859                 pdata->cfg_gpio(to_platform_device(i2c->dev));
 860         else if (IS_ERR(i2c->pctrl) && s3c24xx_i2c_parse_dt_gpio(i2c))
 861                 return -EINVAL;
 862
 863         /* write slave address */
 864
 865         writeb(pdata->slave_addr, i2c->regs + S3C2410_IICADD);
 866
 867         dev_info(i2c->dev, "slave address 0x%02x\n", pdata->slave_addr);
 868
 869         writel(iicon, i2c->regs + S3C2410_IICCON);
 870
 871         /* we need to work out the divisors for the clock... */
 872
 873         if (s3c24xx_i2c_clockrate(i2c, &freq) != 0) {
 874                 writel(0, i2c->regs + S3C2410_IICCON);
 875                 dev_err(i2c->dev, "cannot meet bus frequency required\n");
 876                 return -EINVAL;
 877         }
 878
 879         /* todo - check that the i2c lines aren't being dragged anywhere */
 880
 881         dev_info(i2c->dev, "bus frequency set to %d KHz\n", freq);
 882         dev_dbg(i2c->dev, "S3C2410_IICCON=0x%02lx\n", iicon);
 883
 884         return 0;
 885 }
 886
 887 #ifdef CONFIG_OF
 888 /* s3c24xx_i2c_parse_dt
 889  *
 890  * Parse the device tree node and retreive the platform data.
 891 */
 892
 893 static void
 894 s3c24xx_i2c_parse_dt(struct device_node *np, struct s3c24xx_i2c *i2c)
 895 {
 896         struct s3c2410_platform_i2c *pdata = i2c->pdata;
 897
 898         if (!np)
 899                 return;
 900
 901         pdata->bus_num = -1; /* i2c bus number is dynamically assigned */
 902         of_property_read_u32(np, "samsung,i2c-sda-delay", &pdata->sda_delay);
 903         of_property_read_u32(np, "samsung,i2c-slave-addr", &pdata->slave_addr);
 904         of_property_read_u32(np, "samsung,i2c-max-bus-freq",
 905                                 (u32 *)&pdata->frequency);
 906 }
 907 #else
 908 static void
 909 s3c24xx_i2c_parse_dt(struct device_node *np, struct s3c24xx_i2c *i2c)
 910 {
 911         return;
 912 }
 913 #endif
 914
 915 /* s3c24xx_i2c_probe
 916  *
 917  * called by the bus driver when a suitable device is found
 918 */
 919
 920 static int s3c24xx_i2c_probe(struct platform_device *pdev)
 921 {
 922         struct s3c24xx_i2c *i2c;
 923         struct s3c2410_platform_i2c *pdata = NULL;
 924         struct resource *res;
 925         int ret;
 926
 927         if (!pdev->dev.of_node) {
 928                 pdata = pdev->dev.platform_data;
 929                 if (!pdata) {
 930                         dev_err(&pdev->dev, "no platform data\n");
 931                         return -EINVAL;
 932                 }
 933         }
 934
 935         i2c = devm_kzalloc(&pdev->dev, sizeof(struct s3c24xx_i2c), GFP_KERNEL);
 936         if (!i2c) {
 937                 dev_err(&pdev->dev, "no memory for state\n");
 938                 return -ENOMEM;
 939         }
 940
 941         i2c->pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
 942         if (!i2c->pdata) {
 943                 ret = -ENOMEM;
 944                 goto err_noclk;
 945         }
 946
 947         i2c->quirks = s3c24xx_get_device_quirks(pdev);
 948         if (pdata)
 949                 memcpy(i2c->pdata, pdata, sizeof(*pdata));
 950         else
 951                 s3c24xx_i2c_parse_dt(pdev->dev.of_node, i2c);
 952
 953         strlcpy(i2c->adap.name, "s3c2410-i2c", sizeof(i2c->adap.name));
 954         i2c->adap.owner   = THIS_MODULE;
 955         i2c->adap.algo    = &s3c24xx_i2c_algorithm;
 956         i2c->adap.retries = 2;
 957         i2c->adap.class   = I2C_CLASS_HWMON | I2C_CLASS_SPD;
 958         i2c->tx_setup     = 50;
 959
 960         init_waitqueue_head(&i2c->wait);
 961
 962         /* find the clock and enable it */
 963
 964         i2c->dev = &pdev->dev;
 965         i2c->clk = clk_get(&pdev->dev, "i2c");
 966         if (IS_ERR(i2c->clk)) {
 967                 dev_err(&pdev->dev, "cannot get clock\n");
 968                 ret = -ENOENT;
 969                 goto err_noclk;
 970         }
 971
 972         dev_dbg(&pdev->dev, "clock source %p\n", i2c->clk);
 973
 974         clk_prepare_enable(i2c->clk);
 975
 976         /* map the registers */
 977
 978         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 979         if (res == NULL) {
 980                 dev_err(&pdev->dev, "cannot find IO resource\n");
 981                 ret = -ENOENT;
 982                 goto err_clk;
 983         }
 984
 985         i2c->regs = devm_request_and_ioremap(&pdev->dev, res);
 986
 987         if (i2c->regs == NULL) {
 988                 dev_err(&pdev->dev, "cannot map IO\n");
 989                 ret = -ENXIO;
 990                 goto err_clk;
 991         }
 992
 993         dev_dbg(&pdev->dev, "registers %p (%p)\n",
 994                 i2c->regs, res);
 995
 996         /* setup info block for the i2c core */
 997
 998         i2c->adap.algo_data = i2c;
 999         i2c->adap.dev.parent = &pdev->dev;
1000
1001         i2c->pctrl = devm_pinctrl_get_select_default(i2c->dev);
1002
1003         /* initialise the i2c controller */
1004
1005         ret = s3c24xx_i2c_init(i2c);
1006         if (ret != 0)
1007                 goto err_clk;
1008
1009         /* find the IRQ for this unit (note, this relies on the init call to
1010          * ensure no current IRQs pending
1011          */
1012
1013         i2c->irq = ret = platform_get_irq(pdev, 0);
1014         if (ret <= 0) {
1015                 dev_err(&pdev->dev, "cannot find IRQ\n");
1016                 goto err_clk;
1017         }
1018
1019         ret = request_irq(i2c->irq, s3c24xx_i2c_irq, 0,
1020                           dev_name(&pdev->dev), i2c);
1021
1022         if (ret != 0) {
1023                 dev_err(&pdev->dev, "cannot claim IRQ %d\n", i2c->irq);
1024                 goto err_clk;
1025         }
1026
1027         ret = s3c24xx_i2c_register_cpufreq(i2c);
1028         if (ret < 0) {
1029                 dev_err(&pdev->dev, "failed to register cpufreq notifier\n");
1030                 goto err_irq;
1031         }
1032
1033         /* Note, previous versions of the driver used i2c_add_adapter()
1034          * to add the bus at any number. We now pass the bus number via
1035          * the platform data, so if unset it will now default to always
1036          * being bus 0.
1037          */
1038
1039         i2c->adap.nr = i2c->pdata->bus_num;
1040         i2c->adap.dev.of_node = pdev->dev.of_node;
1041
1042         ret = i2c_add_numbered_adapter(&i2c->adap);
1043         if (ret < 0) {
1044                 dev_err(&pdev->dev, "failed to add bus to i2c core\n");
1045                 goto err_cpufreq;
1046         }
1047
1048         of_i2c_register_devices(&i2c->adap);
1049         platform_set_drvdata(pdev, i2c);
1050
1051         pm_runtime_enable(&pdev->dev);
1052         pm_runtime_enable(&i2c->adap.dev);
1053
1054         dev_info(&pdev->dev, "%s: S3C I2C adapter\n", dev_name(&i2c->adap.dev));
1055         clk_disable_unprepare(i2c->clk);
1056         return 0;
1057
1058  err_cpufreq:
1059         s3c24xx_i2c_deregister_cpufreq(i2c);
1060
1061  err_irq:
1062         free_irq(i2c->irq, i2c);
1063
1064  err_clk:
1065         clk_disable_unprepare(i2c->clk);
1066         clk_put(i2c->clk);
1067
1068  err_noclk:
1069         return ret;
1070 }
1071
1072 /* s3c24xx_i2c_remove
1073  *
1074  * called when device is removed from the bus
1075 */
1076
1077 static int s3c24xx_i2c_remove(struct platform_device *pdev)
1078 {
1079         struct s3c24xx_i2c *i2c = platform_get_drvdata(pdev);
1080
1081         pm_runtime_disable(&i2c->adap.dev);
1082         pm_runtime_disable(&pdev->dev);
1083
1084         s3c24xx_i2c_deregister_cpufreq(i2c);
1085
1086         i2c_del_adapter(&i2c->adap);
1087         free_irq(i2c->irq, i2c);
1088
1089         clk_disable_unprepare(i2c->clk);
1090         clk_put(i2c->clk);
1091
1092         if (pdev->dev.of_node && IS_ERR(i2c->pctrl))
1093                 s3c24xx_i2c_dt_gpio_free(i2c);
1094
1095         return 0;
1096 }
1097
1098 #ifdef CONFIG_PM_SLEEP
1099 static int s3c24xx_i2c_suspend_noirq(struct device *dev)
1100 {
1101         struct platform_device *pdev = to_platform_device(dev);
1102         struct s3c24xx_i2c *i2c = platform_get_drvdata(pdev);
1103
1104         i2c->suspended = 1;
1105
1106         return 0;
1107 }
1108
1109 static int s3c24xx_i2c_resume(struct device *dev)
1110 {
1111         struct platform_device *pdev = to_platform_device(dev);
1112         struct s3c24xx_i2c *i2c = platform_get_drvdata(pdev);
1113
1114         i2c->suspended = 0;
1115         clk_prepare_enable(i2c->clk);
1116         s3c24xx_i2c_init(i2c);
1117         clk_disable_unprepare(i2c->clk);
1118
1119         return 0;
1120 }
1121 #endif
1122
1123 #ifdef CONFIG_PM
1124 static const struct dev_pm_ops s3c24xx_i2c_dev_pm_ops = {
1125 #ifdef CONFIG_PM_SLEEP
1126         .suspend_noirq = s3c24xx_i2c_suspend_noirq,
1127         .resume = s3c24xx_i2c_resume,
1128 #endif
1129 };
1130
1131 #define S3C24XX_DEV_PM_OPS (&s3c24xx_i2c_dev_pm_ops)
1132 #else
1133 #define S3C24XX_DEV_PM_OPS NULL
1134 #endif
1135
1136 /* device driver for platform bus bits */
1137
1138 static struct platform_driver s3c24xx_i2c_driver = {
1139         .probe          = s3c24xx_i2c_probe,
1140         .remove         = s3c24xx_i2c_remove,
1141         .id_table       = s3c24xx_driver_ids,
1142         .driver         = {
1143                 .owner  = THIS_MODULE,
1144                 .name   = "s3c-i2c",
1145                 .pm     = S3C24XX_DEV_PM_OPS,
1146                 .of_match_table = of_match_ptr(s3c24xx_i2c_match),
1147         },
1148 };
1149
1150 static int __init i2c_adap_s3c_init(void)
1151 {
1152         return platform_driver_register(&s3c24xx_i2c_driver);
1153 }
1154 subsys_initcall(i2c_adap_s3c_init);
1155
1156 static void __exit i2c_adap_s3c_exit(void)
1157 {
1158         platform_driver_unregister(&s3c24xx_i2c_driver);
1159 }
1160 module_exit(i2c_adap_s3c_exit);
1161
1162 MODULE_DESCRIPTION("S3C24XX I2C Bus driver");
1163 MODULE_AUTHOR("Ben Dooks, <ben@simtec.co.uk>");
1164 MODULE_LICENSE("GPL");