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
  19 #include <linux/kernel.h>
  20 #include <linux/module.h>
  21
  22 #include <linux/i2c.h>
  23 #include <linux/init.h>
  24 #include <linux/time.h>
  25 #include <linux/interrupt.h>
  26 #include <linux/delay.h>
  27 #include <linux/errno.h>
  28 #include <linux/err.h>
  29 #include <linux/platform_device.h>
  30 #include <linux/pm_runtime.h>
  31 #include <linux/clk.h>
  32 #include <linux/cpufreq.h>
  33 #include <linux/slab.h>
  34 #include <linux/io.h>
  35 #include <linux/of.h>
  36 #include <linux/of_gpio.h>
  37 #include <linux/pinctrl/consumer.h>
  38 #include <linux/mfd/syscon.h>
  39 #include <linux/regmap.h>
  40
  41 #include <asm/irq.h>
  42
  43 #include <linux/platform_data/i2c-s3c2410.h>
  44
  45 /* see s3c2410x user guide, v1.1, section 9 (p447) for more info */
  46
  47 #define S3C2410_IICCON                  0x00
  48 #define S3C2410_IICSTAT                 0x04
  49 #define S3C2410_IICADD                  0x08
  50 #define S3C2410_IICDS                   0x0C
  51 #define S3C2440_IICLC                   0x10
  52
  53 #define S3C2410_IICCON_ACKEN            (1 << 7)
  54 #define S3C2410_IICCON_TXDIV_16         (0 << 6)
  55 #define S3C2410_IICCON_TXDIV_512        (1 << 6)
  56 #define S3C2410_IICCON_IRQEN            (1 << 5)
  57 #define S3C2410_IICCON_IRQPEND          (1 << 4)
  58 #define S3C2410_IICCON_SCALE(x)         ((x) & 0xf)
  59 #define S3C2410_IICCON_SCALEMASK        (0xf)
  60
  61 #define S3C2410_IICSTAT_MASTER_RX       (2 << 6)
  62 #define S3C2410_IICSTAT_MASTER_TX       (3 << 6)
  63 #define S3C2410_IICSTAT_SLAVE_RX        (0 << 6)
  64 #define S3C2410_IICSTAT_SLAVE_TX        (1 << 6)
  65 #define S3C2410_IICSTAT_MODEMASK        (3 << 6)
  66
  67 #define S3C2410_IICSTAT_START           (1 << 5)
  68 #define S3C2410_IICSTAT_BUSBUSY         (1 << 5)
  69 #define S3C2410_IICSTAT_TXRXEN          (1 << 4)
  70 #define S3C2410_IICSTAT_ARBITR          (1 << 3)
  71 #define S3C2410_IICSTAT_ASSLAVE         (1 << 2)
  72 #define S3C2410_IICSTAT_ADDR0           (1 << 1)
  73 #define S3C2410_IICSTAT_LASTBIT         (1 << 0)
  74
  75 #define S3C2410_IICLC_SDA_DELAY0        (0 << 0)
  76 #define S3C2410_IICLC_SDA_DELAY5        (1 << 0)
  77 #define S3C2410_IICLC_SDA_DELAY10       (2 << 0)
  78 #define S3C2410_IICLC_SDA_DELAY15       (3 << 0)
  79 #define S3C2410_IICLC_SDA_DELAY_MASK    (3 << 0)
  80
  81 #define S3C2410_IICLC_FILTER_ON         (1 << 2)
  82
  83 /* Treat S3C2410 as baseline hardware, anything else is supported via quirks */
  84 #define QUIRK_S3C2440           (1 << 0)
  85 #define QUIRK_HDMIPHY           (1 << 1)
  86 #define QUIRK_NO_GPIO           (1 << 2)
  87 #define QUIRK_POLL              (1 << 3)
  88
  89 /* Max time to wait for bus to become idle after a xfer (in us) */
  90 #define S3C2410_IDLE_TIMEOUT    5000
  91
  92 /* Exynos5 Sysreg offset */
  93 #define EXYNOS5_SYS_I2C_CFG     0x0234
  94
  95 /* i2c controller state */
  96 enum s3c24xx_i2c_state {
  97         STATE_IDLE,
  98         STATE_START,
  99         STATE_READ,
 100         STATE_WRITE,
 101         STATE_STOP
 102 };
 103
 104 struct s3c24xx_i2c {
 105         wait_queue_head_t       wait;
 106         kernel_ulong_t          quirks;
 107         unsigned int            suspended:1;
 108
 109         struct i2c_msg          *msg;
 110         unsigned int            msg_num;
 111         unsigned int            msg_idx;
 112         unsigned int            msg_ptr;
 113
 114         unsigned int            tx_setup;
 115         unsigned int            irq;
 116
 117         enum s3c24xx_i2c_state  state;
 118         unsigned long           clkrate;
 119
 120         void __iomem            *regs;
 121         struct clk              *clk;
 122         struct device           *dev;
 123         struct i2c_adapter      adap;
 124
 125         struct s3c2410_platform_i2c     *pdata;
 126         int                     gpios[2];
 127         struct pinctrl          *pctrl;
 128 #if defined(CONFIG_ARM_S3C24XX_CPUFREQ)
 129         struct notifier_block   freq_transition;
 130 #endif
 131         struct regmap           *sysreg;
 132         unsigned int            sys_i2c_cfg;
 133 };
 134
 135 static struct platform_device_id s3c24xx_driver_ids[] = {
 136         {
 137                 .name           = "s3c2410-i2c",
 138                 .driver_data    = 0,
 139         }, {
 140                 .name           = "s3c2440-i2c",
 141                 .driver_data    = QUIRK_S3C2440,
 142         }, {
 143                 .name           = "s3c2440-hdmiphy-i2c",
 144                 .driver_data    = QUIRK_S3C2440 | QUIRK_HDMIPHY | QUIRK_NO_GPIO,
 145         }, { },
 146 };
 147 MODULE_DEVICE_TABLE(platform, s3c24xx_driver_ids);
 148
 149 static int i2c_s3c_irq_nextbyte(struct s3c24xx_i2c *i2c, unsigned long iicstat);
 150
 151 #ifdef CONFIG_OF
 152 static const struct of_device_id s3c24xx_i2c_match[] = {
 153         { .compatible = "samsung,s3c2410-i2c", .data = (void *)0 },
 154         { .compatible = "samsung,s3c2440-i2c", .data = (void *)QUIRK_S3C2440 },
 155         { .compatible = "samsung,s3c2440-hdmiphy-i2c",
 156           .data = (void *)(QUIRK_S3C2440 | QUIRK_HDMIPHY | QUIRK_NO_GPIO) },
 157         { .compatible = "samsung,exynos5440-i2c",
 158           .data = (void *)(QUIRK_S3C2440 | QUIRK_NO_GPIO) },
 159         { .compatible = "samsung,exynos5-sata-phy-i2c",
 160           .data = (void *)(QUIRK_S3C2440 | QUIRK_POLL | QUIRK_NO_GPIO) },
 161         {},
 162 };
 163 MODULE_DEVICE_TABLE(of, s3c24xx_i2c_match);
 164 #endif
 165
 166 /* s3c24xx_get_device_quirks
 167  *
 168  * Get controller type either from device tree or platform device variant.
 169 */
 170
 171 static inline kernel_ulong_t s3c24xx_get_device_quirks(struct platform_device *pdev)
 172 {
 173         if (pdev->dev.of_node) {
 174                 const struct of_device_id *match;
 175                 match = of_match_node(s3c24xx_i2c_match, pdev->dev.of_node);
 176                 return (kernel_ulong_t)match->data;
 177         }
 178
 179         return platform_get_device_id(pdev)->driver_data;
 180 }
 181
 182 /* s3c24xx_i2c_master_complete
 183  *
 184  * complete the message and wake up the caller, using the given return code,
 185  * or zero to mean ok.
 186 */
 187
 188 static inline void s3c24xx_i2c_master_complete(struct s3c24xx_i2c *i2c, int ret)
 189 {
 190         dev_dbg(i2c->dev, "master_complete %d\n", ret);
 191
 192         i2c->msg_ptr = 0;
 193         i2c->msg = NULL;
 194         i2c->msg_idx++;
 195         i2c->msg_num = 0;
 196         if (ret)
 197                 i2c->msg_idx = ret;
 198
 199         if (!(i2c->quirks & QUIRK_POLL))
 200                 wake_up(&i2c->wait);
 201 }
 202
 203 static inline void s3c24xx_i2c_disable_ack(struct s3c24xx_i2c *i2c)
 204 {
 205         unsigned long tmp;
 206
 207         tmp = readl(i2c->regs + S3C2410_IICCON);
 208         writel(tmp & ~S3C2410_IICCON_ACKEN, i2c->regs + S3C2410_IICCON);
 209 }
 210
 211 static inline void s3c24xx_i2c_enable_ack(struct s3c24xx_i2c *i2c)
 212 {
 213         unsigned long tmp;
 214
 215         tmp = readl(i2c->regs + S3C2410_IICCON);
 216         writel(tmp | S3C2410_IICCON_ACKEN, i2c->regs + S3C2410_IICCON);
 217 }
 218
 219 /* irq enable/disable functions */
 220
 221 static inline void s3c24xx_i2c_disable_irq(struct s3c24xx_i2c *i2c)
 222 {
 223         unsigned long tmp;
 224
 225         tmp = readl(i2c->regs + S3C2410_IICCON);
 226         writel(tmp & ~S3C2410_IICCON_IRQEN, i2c->regs + S3C2410_IICCON);
 227 }
 228
 229 static inline void s3c24xx_i2c_enable_irq(struct s3c24xx_i2c *i2c)
 230 {
 231         unsigned long tmp;
 232
 233         tmp = readl(i2c->regs + S3C2410_IICCON);
 234         writel(tmp | S3C2410_IICCON_IRQEN, i2c->regs + S3C2410_IICCON);
 235 }
 236
 237 static bool is_ack(struct s3c24xx_i2c *i2c)
 238 {
 239         int tries;
 240
 241         for (tries = 50; tries; --tries) {
 242                 if (readl(i2c->regs + S3C2410_IICCON)
 243                         & S3C2410_IICCON_IRQPEND) {
 244                         if (!(readl(i2c->regs + S3C2410_IICSTAT)
 245                                 & S3C2410_IICSTAT_LASTBIT))
 246                                 return true;
 247                 }
 248                 usleep_range(1000, 2000);
 249         }
 250         dev_err(i2c->dev, "ack was not received\n");
 251         return false;
 252 }
 253
 254 /* s3c24xx_i2c_message_start
 255  *
 256  * put the start of a message onto the bus
 257 */
 258
 259 static void s3c24xx_i2c_message_start(struct s3c24xx_i2c *i2c,
 260                                       struct i2c_msg *msg)
 261 {
 262         unsigned int addr = (msg->addr & 0x7f) << 1;
 263         unsigned long stat;
 264         unsigned long iiccon;
 265
 266         stat = 0;
 267         stat |=  S3C2410_IICSTAT_TXRXEN;
 268
 269         if (msg->flags & I2C_M_RD) {
 270                 stat |= S3C2410_IICSTAT_MASTER_RX;
 271                 addr |= 1;
 272         } else
 273                 stat |= S3C2410_IICSTAT_MASTER_TX;
 274
 275         if (msg->flags & I2C_M_REV_DIR_ADDR)
 276                 addr ^= 1;
 277
 278         /* todo - check for whether ack wanted or not */
 279         s3c24xx_i2c_enable_ack(i2c);
 280
 281         iiccon = readl(i2c->regs + S3C2410_IICCON);
 282         writel(stat, i2c->regs + S3C2410_IICSTAT);
 283
 284         dev_dbg(i2c->dev, "START: %08lx to IICSTAT, %02x to DS\n", stat, addr);
 285         writeb(addr, i2c->regs + S3C2410_IICDS);
 286
 287         /* delay here to ensure the data byte has gotten onto the bus
 288          * before the transaction is started */
 289
 290         ndelay(i2c->tx_setup);
 291
 292         dev_dbg(i2c->dev, "iiccon, %08lx\n", iiccon);
 293         writel(iiccon, i2c->regs + S3C2410_IICCON);
 294
 295         stat |= S3C2410_IICSTAT_START;
 296         writel(stat, i2c->regs + S3C2410_IICSTAT);
 297
 298         if (i2c->quirks & QUIRK_POLL) {
 299                 while ((i2c->msg_num != 0) && is_ack(i2c)) {
 300                         i2c_s3c_irq_nextbyte(i2c, stat);
 301                         stat = readl(i2c->regs + S3C2410_IICSTAT);
 302
 303                         if (stat & S3C2410_IICSTAT_ARBITR)
 304                                 dev_err(i2c->dev, "deal with arbitration loss\n");
 305                 }
 306         }
 307 }
 308
 309 static inline void s3c24xx_i2c_stop(struct s3c24xx_i2c *i2c, int ret)
 310 {
 311         unsigned long iicstat = readl(i2c->regs + S3C2410_IICSTAT);
 312
 313         dev_dbg(i2c->dev, "STOP\n");
 314
 315         /*
 316          * The datasheet says that the STOP sequence should be:
 317          *  1) I2CSTAT.5 = 0    - Clear BUSY (or 'generate STOP')
 318          *  2) I2CCON.4 = 0     - Clear IRQPEND
 319          *  3) Wait until the stop condition takes effect.
 320          *  4*) I2CSTAT.4 = 0   - Clear TXRXEN
 321          *
 322          * Where, step "4*" is only for buses with the "HDMIPHY" quirk.
 323          *
 324          * However, after much experimentation, it appears that:
 325          * a) normal buses automatically clear BUSY and transition from
 326          *    Master->Slave when they complete generating a STOP condition.
 327          *    Therefore, step (3) can be done in doxfer() by polling I2CCON.4
 328          *    after starting the STOP generation here.
 329          * b) HDMIPHY bus does neither, so there is no way to do step 3.
 330          *    There is no indication when this bus has finished generating
 331          *    STOP.
 332          *
 333          * In fact, we have found that as soon as the IRQPEND bit is cleared in
 334          * step 2, the HDMIPHY bus generates the STOP condition, and then
 335          * immediately starts transferring another data byte, even though the
 336          * bus is supposedly stopped.  This is presumably because the bus is
 337          * still in "Master" mode, and its BUSY bit is still set.
 338          *
 339          * To avoid these extra post-STOP transactions on HDMI phy devices, we
 340          * just disable Serial Output on the bus (I2CSTAT.4 = 0) directly,
 341          * instead of first generating a proper STOP condition.  This should
 342          * float SDA & SCK terminating the transfer.  Subsequent transfers
 343          *  start with a proper START condition, and proceed normally.
 344          *
 345          * The HDMIPHY bus is an internal bus that always has exactly two
 346          * devices, the host as Master and the HDMIPHY device as the slave.
 347          * Skipping the STOP condition has been tested on this bus and works.
 348          */
 349         if (i2c->quirks & QUIRK_HDMIPHY) {
 350                 /* Stop driving the I2C pins */
 351                 iicstat &= ~S3C2410_IICSTAT_TXRXEN;
 352         } else {
 353                 /* stop the transfer */
 354                 iicstat &= ~S3C2410_IICSTAT_START;
 355         }
 356         writel(iicstat, i2c->regs + S3C2410_IICSTAT);
 357
 358         i2c->state = STATE_STOP;
 359
 360         s3c24xx_i2c_master_complete(i2c, ret);
 361         s3c24xx_i2c_disable_irq(i2c);
 362 }
 363
 364 /* helper functions to determine the current state in the set of
 365  * messages we are sending */
 366
 367 /* is_lastmsg()
 368  *
 369  * returns TRUE if the current message is the last in the set
 370 */
 371
 372 static inline int is_lastmsg(struct s3c24xx_i2c *i2c)
 373 {
 374         return i2c->msg_idx >= (i2c->msg_num - 1);
 375 }
 376
 377 /* is_msglast
 378  *
 379  * returns TRUE if we this is the last byte in the current message
 380 */
 381
 382 static inline int is_msglast(struct s3c24xx_i2c *i2c)
 383 {
 384         /* msg->len is always 1 for the first byte of smbus block read.
 385          * Actual length will be read from slave. More bytes will be
 386          * read according to the length then. */
 387         if (i2c->msg->flags & I2C_M_RECV_LEN && i2c->msg->len == 1)
 388                 return 0;
 389
 390         return i2c->msg_ptr == i2c->msg->len-1;
 391 }
 392
 393 /* is_msgend
 394  *
 395  * returns TRUE if we reached the end of the current message
 396 */
 397
 398 static inline int is_msgend(struct s3c24xx_i2c *i2c)
 399 {
 400         return i2c->msg_ptr >= i2c->msg->len;
 401 }
 402
 403 /* i2c_s3c_irq_nextbyte
 404  *
 405  * process an interrupt and work out what to do
 406  */
 407
 408 static int i2c_s3c_irq_nextbyte(struct s3c24xx_i2c *i2c, unsigned long iicstat)
 409 {
 410         unsigned long tmp;
 411         unsigned char byte;
 412         int ret = 0;
 413
 414         switch (i2c->state) {
 415
 416         case STATE_IDLE:
 417                 dev_err(i2c->dev, "%s: called in STATE_IDLE\n", __func__);
 418                 goto out;
 419
 420         case STATE_STOP:
 421                 dev_err(i2c->dev, "%s: called in STATE_STOP\n", __func__);
 422                 s3c24xx_i2c_disable_irq(i2c);
 423                 goto out_ack;
 424
 425         case STATE_START:
 426                 /* last thing we did was send a start condition on the
 427                  * bus, or started a new i2c message
 428                  */
 429
 430                 if (iicstat & S3C2410_IICSTAT_LASTBIT &&
 431                     !(i2c->msg->flags & I2C_M_IGNORE_NAK)) {
 432                         /* ack was not received... */
 433
 434                         dev_dbg(i2c->dev, "ack was not received\n");
 435                         s3c24xx_i2c_stop(i2c, -ENXIO);
 436                         goto out_ack;
 437                 }
 438
 439                 if (i2c->msg->flags & I2C_M_RD)
 440                         i2c->state = STATE_READ;
 441                 else
 442                         i2c->state = STATE_WRITE;
 443
 444                 /* terminate the transfer if there is nothing to do
 445                  * as this is used by the i2c probe to find devices. */
 446
 447                 if (is_lastmsg(i2c) && i2c->msg->len == 0) {
 448                         s3c24xx_i2c_stop(i2c, 0);
 449                         goto out_ack;
 450                 }
 451
 452                 if (i2c->state == STATE_READ)
 453                         goto prepare_read;
 454
 455                 /* fall through to the write state, as we will need to
 456                  * send a byte as well */
 457
 458         case STATE_WRITE:
 459                 /* we are writing data to the device... check for the
 460                  * end of the message, and if so, work out what to do
 461                  */
 462
 463                 if (!(i2c->msg->flags & I2C_M_IGNORE_NAK)) {
 464                         if (iicstat & S3C2410_IICSTAT_LASTBIT) {
 465                                 dev_dbg(i2c->dev, "WRITE: No Ack\n");
 466
 467                                 s3c24xx_i2c_stop(i2c, -ECONNREFUSED);
 468                                 goto out_ack;
 469                         }
 470                 }
 471
 472  retry_write:
 473
 474                 if (!is_msgend(i2c)) {
 475                         byte = i2c->msg->buf[i2c->msg_ptr++];
 476                         writeb(byte, i2c->regs + S3C2410_IICDS);
 477
 478                         /* delay after writing the byte to allow the
 479                          * data setup time on the bus, as writing the
 480                          * data to the register causes the first bit
 481                          * to appear on SDA, and SCL will change as
 482                          * soon as the interrupt is acknowledged */
 483
 484                         ndelay(i2c->tx_setup);
 485
 486                 } else if (!is_lastmsg(i2c)) {
 487                         /* we need to go to the next i2c message */
 488
 489                         dev_dbg(i2c->dev, "WRITE: Next Message\n");
 490
 491                         i2c->msg_ptr = 0;
 492                         i2c->msg_idx++;
 493                         i2c->msg++;
 494
 495                         /* check to see if we need to do another message */
 496                         if (i2c->msg->flags & I2C_M_NOSTART) {
 497
 498                                 if (i2c->msg->flags & I2C_M_RD) {
 499                                         /* cannot do this, the controller
 500                                          * forces us to send a new START
 501                                          * when we change direction */
 502
 503                                         s3c24xx_i2c_stop(i2c, -EINVAL);
 504                                 }
 505
 506                                 goto retry_write;
 507                         } else {
 508                                 /* send the new start */
 509                                 s3c24xx_i2c_message_start(i2c, i2c->msg);
 510                                 i2c->state = STATE_START;
 511                         }
 512
 513                 } else {
 514                         /* send stop */
 515
 516                         s3c24xx_i2c_stop(i2c, 0);
 517                 }
 518                 break;
 519
 520         case STATE_READ:
 521                 /* we have a byte of data in the data register, do
 522                  * something with it, and then work out whether we are
 523                  * going to do any more read/write
 524                  */
 525
 526                 byte = readb(i2c->regs + S3C2410_IICDS);
 527                 i2c->msg->buf[i2c->msg_ptr++] = byte;
 528
 529                 /* Add actual length to read for smbus block read */
 530                 if (i2c->msg->flags & I2C_M_RECV_LEN && i2c->msg->len == 1)
 531                         i2c->msg->len += byte;
 532  prepare_read:
 533                 if (is_msglast(i2c)) {
 534                         /* last byte of buffer */
 535
 536                         if (is_lastmsg(i2c))
 537                                 s3c24xx_i2c_disable_ack(i2c);
 538
 539                 } else if (is_msgend(i2c)) {
 540                         /* ok, we've read the entire buffer, see if there
 541                          * is anything else we need to do */
 542
 543                         if (is_lastmsg(i2c)) {
 544                                 /* last message, send stop and complete */
 545                                 dev_dbg(i2c->dev, "READ: Send Stop\n");
 546
 547                                 s3c24xx_i2c_stop(i2c, 0);
 548                         } else {
 549                                 /* go to the next transfer */
 550                                 dev_dbg(i2c->dev, "READ: Next Transfer\n");
 551
 552                                 i2c->msg_ptr = 0;
 553                                 i2c->msg_idx++;
 554                                 i2c->msg++;
 555                         }
 556                 }
 557
 558                 break;
 559         }
 560
 561         /* acknowlegde the IRQ and get back on with the work */
 562
 563  out_ack:
 564         tmp = readl(i2c->regs + S3C2410_IICCON);
 565         tmp &= ~S3C2410_IICCON_IRQPEND;
 566         writel(tmp, i2c->regs + S3C2410_IICCON);
 567  out:
 568         return ret;
 569 }
 570
 571 /* s3c24xx_i2c_irq
 572  *
 573  * top level IRQ servicing routine
 574 */
 575
 576 static irqreturn_t s3c24xx_i2c_irq(int irqno, void *dev_id)
 577 {
 578         struct s3c24xx_i2c *i2c = dev_id;
 579         unsigned long status;
 580         unsigned long tmp;
 581
 582         status = readl(i2c->regs + S3C2410_IICSTAT);
 583
 584         if (status & S3C2410_IICSTAT_ARBITR) {
 585                 /* deal with arbitration loss */
 586                 dev_err(i2c->dev, "deal with arbitration loss\n");
 587         }
 588
 589         if (i2c->state == STATE_IDLE) {
 590                 dev_dbg(i2c->dev, "IRQ: error i2c->state == IDLE\n");
 591
 592                 tmp = readl(i2c->regs + S3C2410_IICCON);
 593                 tmp &= ~S3C2410_IICCON_IRQPEND;
 594                 writel(tmp, i2c->regs +  S3C2410_IICCON);
 595                 goto out;
 596         }
 597
 598         /* pretty much this leaves us with the fact that we've
 599          * transmitted or received whatever byte we last sent */
 600
 601         i2c_s3c_irq_nextbyte(i2c, status);
 602
 603  out:
 604         return IRQ_HANDLED;
 605 }
 606
 607 /*
 608  * Disable the bus so that we won't get any interrupts from now on, or try
 609  * to drive any lines. This is the default state when we don't have
 610  * anything to send/receive.
 611  *
 612  * If there is an event on the bus, or we have a pre-existing event at
 613  * kernel boot time, we may not notice the event and the I2C controller
 614  * will lock the bus with the I2C clock line low indefinitely.
 615  */
 616 static inline void s3c24xx_i2c_disable_bus(struct s3c24xx_i2c *i2c)
 617 {
 618         unsigned long tmp;
 619
 620         /* Stop driving the I2C pins */
 621         tmp = readl(i2c->regs + S3C2410_IICSTAT);
 622         tmp &= ~S3C2410_IICSTAT_TXRXEN;
 623         writel(tmp, i2c->regs + S3C2410_IICSTAT);
 624
 625         /* We don't expect any interrupts now, and don't want send acks */
 626         tmp = readl(i2c->regs + S3C2410_IICCON);
 627         tmp &= ~(S3C2410_IICCON_IRQEN | S3C2410_IICCON_IRQPEND |
 628                 S3C2410_IICCON_ACKEN);
 629         writel(tmp, i2c->regs + S3C2410_IICCON);
 630 }
 631
 632
 633 /* s3c24xx_i2c_set_master
 634  *
 635  * get the i2c bus for a master transaction
 636 */
 637
 638 static int s3c24xx_i2c_set_master(struct s3c24xx_i2c *i2c)
 639 {
 640         unsigned long iicstat;
 641         int timeout = 400;
 642
 643         while (timeout-- > 0) {
 644                 iicstat = readl(i2c->regs + S3C2410_IICSTAT);
 645
 646                 if (!(iicstat & S3C2410_IICSTAT_BUSBUSY))
 647                         return 0;
 648
 649                 msleep(1);
 650         }
 651
 652         return -ETIMEDOUT;
 653 }
 654
 655 /* s3c24xx_i2c_wait_idle
 656  *
 657  * wait for the i2c bus to become idle.
 658 */
 659
 660 static void s3c24xx_i2c_wait_idle(struct s3c24xx_i2c *i2c)
 661 {
 662         unsigned long iicstat;
 663         ktime_t start, now;
 664         unsigned long delay;
 665         int spins;
 666
 667         /* ensure the stop has been through the bus */
 668
 669         dev_dbg(i2c->dev, "waiting for bus idle\n");
 670
 671         start = now = ktime_get();
 672
 673         /*
 674          * Most of the time, the bus is already idle within a few usec of the
 675          * end of a transaction.  However, really slow i2c devices can stretch
 676          * the clock, delaying STOP generation.
 677          *
 678          * On slower SoCs this typically happens within a very small number of
 679          * instructions so busy wait briefly to avoid scheduling overhead.
 680          */
 681         spins = 3;
 682         iicstat = readl(i2c->regs + S3C2410_IICSTAT);
 683         while ((iicstat & S3C2410_IICSTAT_START) && --spins) {
 684                 cpu_relax();
 685                 iicstat = readl(i2c->regs + S3C2410_IICSTAT);
 686         }
 687
 688         /*
 689          * If we do get an appreciable delay as a compromise between idle
 690          * detection latency for the normal, fast case, and system load in the
 691          * slow device case, use an exponential back off in the polling loop,
 692          * up to 1/10th of the total timeout, then continue to poll at a
 693          * constant rate up to the timeout.
 694          */
 695         delay = 1;
 696         while ((iicstat & S3C2410_IICSTAT_START) &&
 697                ktime_us_delta(now, start) < S3C2410_IDLE_TIMEOUT) {
 698                 usleep_range(delay, 2 * delay);
 699                 if (delay < S3C2410_IDLE_TIMEOUT / 10)
 700                         delay <<= 1;
 701                 now = ktime_get();
 702                 iicstat = readl(i2c->regs + S3C2410_IICSTAT);
 703         }
 704
 705         if (iicstat & S3C2410_IICSTAT_START)
 706                 dev_warn(i2c->dev, "timeout waiting for bus idle\n");
 707 }
 708
 709 /* s3c24xx_i2c_doxfer
 710  *
 711  * this starts an i2c transfer
 712 */
 713
 714 static int s3c24xx_i2c_doxfer(struct s3c24xx_i2c *i2c,
 715                               struct i2c_msg *msgs, int num)
 716 {
 717         unsigned long timeout;
 718         int ret;
 719
 720         if (i2c->suspended)
 721                 return -EIO;
 722
 723         ret = s3c24xx_i2c_set_master(i2c);
 724         if (ret != 0) {
 725                 dev_err(i2c->dev, "cannot get bus (error %d)\n", ret);
 726                 ret = -EAGAIN;
 727                 goto out;
 728         }
 729
 730         i2c->msg     = msgs;
 731         i2c->msg_num = num;
 732         i2c->msg_ptr = 0;
 733         i2c->msg_idx = 0;
 734         i2c->state   = STATE_START;
 735
 736         s3c24xx_i2c_enable_irq(i2c);
 737         s3c24xx_i2c_message_start(i2c, msgs);
 738
 739         if (i2c->quirks & QUIRK_POLL) {
 740                 ret = i2c->msg_idx;
 741
 742                 if (ret != num)
 743                         dev_dbg(i2c->dev, "incomplete xfer (%d)\n", ret);
 744
 745                 goto out;
 746         }
 747
 748         timeout = wait_event_timeout(i2c->wait, i2c->msg_num == 0, HZ * 5);
 749
 750         ret = i2c->msg_idx;
 751
 752         /* having these next two as dev_err() makes life very
 753          * noisy when doing an i2cdetect */
 754
 755         if (timeout == 0)
 756                 dev_dbg(i2c->dev, "timeout\n");
 757         else if (ret != num)
 758                 dev_dbg(i2c->dev, "incomplete xfer (%d)\n", ret);
 759
 760         /* For QUIRK_HDMIPHY, bus is already disabled */
 761         if (i2c->quirks & QUIRK_HDMIPHY)
 762                 goto out;
 763
 764         s3c24xx_i2c_wait_idle(i2c);
 765
 766         s3c24xx_i2c_disable_bus(i2c);
 767
 768  out:
 769         i2c->state = STATE_IDLE;
 770
 771         return ret;
 772 }
 773
 774 /* s3c24xx_i2c_xfer
 775  *
 776  * first port of call from the i2c bus code when an message needs
 777  * transferring across the i2c bus.
 778 */
 779
 780 static int s3c24xx_i2c_xfer(struct i2c_adapter *adap,
 781                         struct i2c_msg *msgs, int num)
 782 {
 783         struct s3c24xx_i2c *i2c = (struct s3c24xx_i2c *)adap->algo_data;
 784         int retry;
 785         int ret;
 786
 787         pm_runtime_get_sync(&adap->dev);
 788         ret = clk_enable(i2c->clk);
 789         if (ret)
 790                 return ret;
 791
 792         for (retry = 0; retry < adap->retries; retry++) {
 793
 794                 ret = s3c24xx_i2c_doxfer(i2c, msgs, num);
 795
 796                 if (ret != -EAGAIN) {
 797                         clk_disable(i2c->clk);
 798                         pm_runtime_put(&adap->dev);
 799                         return ret;
 800                 }
 801
 802                 dev_dbg(i2c->dev, "Retrying transmission (%d)\n", retry);
 803
 804                 udelay(100);
 805         }
 806
 807         clk_disable(i2c->clk);
 808         pm_runtime_put(&adap->dev);
 809         return -EREMOTEIO;
 810 }
 811
 812 /* declare our i2c functionality */
 813 static u32 s3c24xx_i2c_func(struct i2c_adapter *adap)
 814 {
 815         return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_NOSTART |
 816                 I2C_FUNC_PROTOCOL_MANGLING;
 817 }
 818
 819 /* i2c bus registration info */
 820
 821 static const struct i2c_algorithm s3c24xx_i2c_algorithm = {
 822         .master_xfer            = s3c24xx_i2c_xfer,
 823         .functionality          = s3c24xx_i2c_func,
 824 };
 825
 826 /* s3c24xx_i2c_calcdivisor
 827  *
 828  * return the divisor settings for a given frequency
 829 */
 830
 831 static int s3c24xx_i2c_calcdivisor(unsigned long clkin, unsigned int wanted,
 832                                    unsigned int *div1, unsigned int *divs)
 833 {
 834         unsigned int calc_divs = clkin / wanted;
 835         unsigned int calc_div1;
 836
 837         if (calc_divs > (16*16))
 838                 calc_div1 = 512;
 839         else
 840                 calc_div1 = 16;
 841
 842         calc_divs += calc_div1-1;
 843         calc_divs /= calc_div1;
 844
 845         if (calc_divs == 0)
 846                 calc_divs = 1;
 847         if (calc_divs > 17)
 848                 calc_divs = 17;
 849
 850         *divs = calc_divs;
 851         *div1 = calc_div1;
 852
 853         return clkin / (calc_divs * calc_div1);
 854 }
 855
 856 /* s3c24xx_i2c_clockrate
 857  *
 858  * work out a divisor for the user requested frequency setting,
 859  * either by the requested frequency, or scanning the acceptable
 860  * range of frequencies until something is found
 861 */
 862
 863 static int s3c24xx_i2c_clockrate(struct s3c24xx_i2c *i2c, unsigned int *got)
 864 {
 865         struct s3c2410_platform_i2c *pdata = i2c->pdata;
 866         unsigned long clkin = clk_get_rate(i2c->clk);
 867         unsigned int divs, div1;
 868         unsigned long target_frequency;
 869         u32 iiccon;
 870         int freq;
 871
 872         i2c->clkrate = clkin;
 873         clkin /= 1000;          /* clkin now in KHz */
 874
 875         dev_dbg(i2c->dev, "pdata desired frequency %lu\n", pdata->frequency);
 876
 877         target_frequency = pdata->frequency ? pdata->frequency : 100000;
 878
 879         target_frequency /= 1000; /* Target frequency now in KHz */
 880
 881         freq = s3c24xx_i2c_calcdivisor(clkin, target_frequency, &div1, &divs);
 882
 883         if (freq > target_frequency) {
 884                 dev_err(i2c->dev,
 885                         "Unable to achieve desired frequency %luKHz."   \
 886                         " Lowest achievable %dKHz\n", target_frequency, freq);
 887                 return -EINVAL;
 888         }
 889
 890         *got = freq;
 891
 892         iiccon = readl(i2c->regs + S3C2410_IICCON);
 893         iiccon &= ~(S3C2410_IICCON_SCALEMASK | S3C2410_IICCON_TXDIV_512);
 894         iiccon |= (divs-1);
 895
 896         if (div1 == 512)
 897                 iiccon |= S3C2410_IICCON_TXDIV_512;
 898
 899         if (i2c->quirks & QUIRK_POLL)
 900                 iiccon |= S3C2410_IICCON_SCALE(2);
 901
 902         writel(iiccon, i2c->regs + S3C2410_IICCON);
 903
 904         if (i2c->quirks & QUIRK_S3C2440) {
 905                 unsigned long sda_delay;
 906
 907                 if (pdata->sda_delay) {
 908                         sda_delay = clkin * pdata->sda_delay;
 909                         sda_delay = DIV_ROUND_UP(sda_delay, 1000000);
 910                         sda_delay = DIV_ROUND_UP(sda_delay, 5);
 911                         if (sda_delay > 3)
 912                                 sda_delay = 3;
 913                         sda_delay |= S3C2410_IICLC_FILTER_ON;
 914                 } else
 915                         sda_delay = 0;
 916
 917                 dev_dbg(i2c->dev, "IICLC=%08lx\n", sda_delay);
 918                 writel(sda_delay, i2c->regs + S3C2440_IICLC);
 919         }
 920
 921         return 0;
 922 }
 923
 924 #if defined(CONFIG_ARM_S3C24XX_CPUFREQ)
 925
 926 #define freq_to_i2c(_n) container_of(_n, struct s3c24xx_i2c, freq_transition)
 927
 928 static int s3c24xx_i2c_cpufreq_transition(struct notifier_block *nb,
 929                                           unsigned long val, void *data)
 930 {
 931         struct s3c24xx_i2c *i2c = freq_to_i2c(nb);
 932         unsigned int got;
 933         int delta_f;
 934         int ret;
 935
 936         delta_f = clk_get_rate(i2c->clk) - i2c->clkrate;
 937
 938         /* if we're post-change and the input clock has slowed down
 939          * or at pre-change and the clock is about to speed up, then
 940          * adjust our clock rate. <0 is slow, >0 speedup.
 941          */
 942
 943         if ((val == CPUFREQ_POSTCHANGE && delta_f < 0) ||
 944             (val == CPUFREQ_PRECHANGE && delta_f > 0)) {
 945                 i2c_lock_adapter(&i2c->adap);
 946                 ret = s3c24xx_i2c_clockrate(i2c, &got);
 947                 i2c_unlock_adapter(&i2c->adap);
 948
 949                 if (ret < 0)
 950                         dev_err(i2c->dev, "cannot find frequency\n");
 951                 else
 952                         dev_info(i2c->dev, "setting freq %d\n", got);
 953         }
 954
 955         return 0;
 956 }
 957
 958 static inline int s3c24xx_i2c_register_cpufreq(struct s3c24xx_i2c *i2c)
 959 {
 960         i2c->freq_transition.notifier_call = s3c24xx_i2c_cpufreq_transition;
 961
 962         return cpufreq_register_notifier(&i2c->freq_transition,
 963                                          CPUFREQ_TRANSITION_NOTIFIER);
 964 }
 965
 966 static inline void s3c24xx_i2c_deregister_cpufreq(struct s3c24xx_i2c *i2c)
 967 {
 968         cpufreq_unregister_notifier(&i2c->freq_transition,
 969                                     CPUFREQ_TRANSITION_NOTIFIER);
 970 }
 971
 972 #else
 973 static inline int s3c24xx_i2c_register_cpufreq(struct s3c24xx_i2c *i2c)
 974 {
 975         return 0;
 976 }
 977
 978 static inline void s3c24xx_i2c_deregister_cpufreq(struct s3c24xx_i2c *i2c)
 979 {
 980 }
 981 #endif
 982
 983 #ifdef CONFIG_OF
 984 static int s3c24xx_i2c_parse_dt_gpio(struct s3c24xx_i2c *i2c)
 985 {
 986         int idx, gpio, ret;
 987
 988         if (i2c->quirks & QUIRK_NO_GPIO)
 989                 return 0;
 990
 991         for (idx = 0; idx < 2; idx++) {
 992                 gpio = of_get_gpio(i2c->dev->of_node, idx);
 993                 if (!gpio_is_valid(gpio)) {
 994                         dev_err(i2c->dev, "invalid gpio[%d]: %d\n", idx, gpio);
 995                         goto free_gpio;
 996                 }
 997                 i2c->gpios[idx] = gpio;
 998
 999                 ret = gpio_request(gpio, "i2c-bus");
1000                 if (ret) {
1001                         dev_err(i2c->dev, "gpio [%d] request failed\n", gpio);
1002                         goto free_gpio;
1003                 }
1004         }
1005         return 0;
1006
1007 free_gpio:
1008         while (--idx >= 0)
1009                 gpio_free(i2c->gpios[idx]);
1010         return -EINVAL;
1011 }
1012
1013 static void s3c24xx_i2c_dt_gpio_free(struct s3c24xx_i2c *i2c)
1014 {
1015         unsigned int idx;
1016
1017         if (i2c->quirks & QUIRK_NO_GPIO)
1018                 return;
1019
1020         for (idx = 0; idx < 2; idx++)
1021                 gpio_free(i2c->gpios[idx]);
1022 }
1023 #else
1024 static int s3c24xx_i2c_parse_dt_gpio(struct s3c24xx_i2c *i2c)
1025 {
1026         return 0;
1027 }
1028
1029 static void s3c24xx_i2c_dt_gpio_free(struct s3c24xx_i2c *i2c)
1030 {
1031 }
1032 #endif
1033
1034 /* s3c24xx_i2c_init
1035  *
1036  * initialise the controller, set the IO lines and frequency
1037 */
1038
1039 static int s3c24xx_i2c_init(struct s3c24xx_i2c *i2c)
1040 {
1041         struct s3c2410_platform_i2c *pdata;
1042         unsigned int freq;
1043
1044         /* get the plafrom data */
1045
1046         pdata = i2c->pdata;
1047
1048         /* write slave address */
1049
1050         writeb(pdata->slave_addr, i2c->regs + S3C2410_IICADD);
1051
1052         dev_info(i2c->dev, "slave address 0x%02x\n", pdata->slave_addr);
1053
1054         writel(0, i2c->regs + S3C2410_IICCON);
1055         writel(0, i2c->regs + S3C2410_IICSTAT);
1056
1057         /* we need to work out the divisors for the clock... */
1058
1059         if (s3c24xx_i2c_clockrate(i2c, &freq) != 0) {
1060                 dev_err(i2c->dev, "cannot meet bus frequency required\n");
1061                 return -EINVAL;
1062         }
1063
1064         /* todo - check that the i2c lines aren't being dragged anywhere */
1065
1066         dev_info(i2c->dev, "bus frequency set to %d KHz\n", freq);
1067         dev_dbg(i2c->dev, "S3C2410_IICCON=0x%02x\n",
1068                 readl(i2c->regs + S3C2410_IICCON));
1069
1070         return 0;
1071 }
1072
1073 #ifdef CONFIG_OF
1074 /* s3c24xx_i2c_parse_dt
1075  *
1076  * Parse the device tree node and retreive the platform data.
1077 */
1078
1079 static void
1080 s3c24xx_i2c_parse_dt(struct device_node *np, struct s3c24xx_i2c *i2c)
1081 {
1082         struct s3c2410_platform_i2c *pdata = i2c->pdata;
1083         int id;
1084
1085         if (!np)
1086                 return;
1087
1088         pdata->bus_num = -1; /* i2c bus number is dynamically assigned */
1089         of_property_read_u32(np, "samsung,i2c-sda-delay", &pdata->sda_delay);
1090         of_property_read_u32(np, "samsung,i2c-slave-addr", &pdata->slave_addr);
1091         of_property_read_u32(np, "samsung,i2c-max-bus-freq",
1092                                 (u32 *)&pdata->frequency);
1093         /*
1094          * Exynos5's legacy i2c controller and new high speed i2c
1095          * controller have muxed interrupt sources. By default the
1096          * interrupts for 4-channel HS-I2C controller are enabled.
1097          * If nodes for first four channels of legacy i2c controller
1098          * are available then re-configure the interrupts via the
1099          * system register.
1100          */
1101         id = of_alias_get_id(np, "i2c");
1102         i2c->sysreg = syscon_regmap_lookup_by_phandle(np,
1103                         "samsung,sysreg-phandle");
1104         if (IS_ERR(i2c->sysreg))
1105                 return;
1106
1107         regmap_update_bits(i2c->sysreg, EXYNOS5_SYS_I2C_CFG, BIT(id), 0);
1108 }
1109 #else
1110 static void
1111 s3c24xx_i2c_parse_dt(struct device_node *np, struct s3c24xx_i2c *i2c)
1112 {
1113         return;
1114 }
1115 #endif
1116
1117 /* s3c24xx_i2c_probe
1118  *
1119  * called by the bus driver when a suitable device is found
1120 */
1121
1122 static int s3c24xx_i2c_probe(struct platform_device *pdev)
1123 {
1124         struct s3c24xx_i2c *i2c;
1125         struct s3c2410_platform_i2c *pdata = NULL;
1126         struct resource *res;
1127         int ret;
1128
1129         if (!pdev->dev.of_node) {
1130                 pdata = dev_get_platdata(&pdev->dev);
1131                 if (!pdata) {
1132                         dev_err(&pdev->dev, "no platform data\n");
1133                         return -EINVAL;
1134                 }
1135         }
1136
1137         i2c = devm_kzalloc(&pdev->dev, sizeof(struct s3c24xx_i2c), GFP_KERNEL);
1138         if (!i2c)
1139                 return -ENOMEM;
1140
1141         i2c->pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
1142         if (!i2c->pdata)
1143                 return -ENOMEM;
1144
1145         i2c->quirks = s3c24xx_get_device_quirks(pdev);
1146         if (pdata)
1147                 memcpy(i2c->pdata, pdata, sizeof(*pdata));
1148         else
1149                 s3c24xx_i2c_parse_dt(pdev->dev.of_node, i2c);
1150
1151         strlcpy(i2c->adap.name, "s3c2410-i2c", sizeof(i2c->adap.name));
1152         i2c->adap.owner = THIS_MODULE;
1153         i2c->adap.algo = &s3c24xx_i2c_algorithm;
1154         i2c->adap.retries = 2;
1155         i2c->adap.class = I2C_CLASS_DEPRECATED;
1156         i2c->tx_setup = 50;
1157
1158         init_waitqueue_head(&i2c->wait);
1159
1160         /* find the clock and enable it */
1161
1162         i2c->dev = &pdev->dev;
1163         i2c->clk = devm_clk_get(&pdev->dev, "i2c");
1164         if (IS_ERR(i2c->clk)) {
1165                 dev_err(&pdev->dev, "cannot get clock\n");
1166                 return -ENOENT;
1167         }
1168
1169         dev_dbg(&pdev->dev, "clock source %p\n", i2c->clk);
1170
1171
1172         /* map the registers */
1173
1174         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1175         i2c->regs = devm_ioremap_resource(&pdev->dev, res);
1176
1177         if (IS_ERR(i2c->regs))
1178                 return PTR_ERR(i2c->regs);
1179
1180         dev_dbg(&pdev->dev, "registers %p (%p)\n",
1181                 i2c->regs, res);
1182
1183         /* setup info block for the i2c core */
1184
1185         i2c->adap.algo_data = i2c;
1186         i2c->adap.dev.parent = &pdev->dev;
1187
1188         i2c->pctrl = devm_pinctrl_get_select_default(i2c->dev);
1189
1190         /* inititalise the i2c gpio lines */
1191
1192         if (i2c->pdata->cfg_gpio) {
1193                 i2c->pdata->cfg_gpio(to_platform_device(i2c->dev));
1194         } else if (IS_ERR(i2c->pctrl) && s3c24xx_i2c_parse_dt_gpio(i2c)) {
1195                 return -EINVAL;
1196         }
1197
1198         /* initialise the i2c controller */
1199
1200         clk_prepare_enable(i2c->clk);
1201         ret = s3c24xx_i2c_init(i2c);
1202         clk_disable(i2c->clk);
1203         if (ret != 0) {
1204                 dev_err(&pdev->dev, "I2C controller init failed\n");
1205                 return ret;
1206         }
1207         /* find the IRQ for this unit (note, this relies on the init call to
1208          * ensure no current IRQs pending
1209          */
1210
1211         if (!(i2c->quirks & QUIRK_POLL)) {
1212                 i2c->irq = ret = platform_get_irq(pdev, 0);
1213                 if (ret <= 0) {
1214                         dev_err(&pdev->dev, "cannot find IRQ\n");
1215                         clk_unprepare(i2c->clk);
1216                         return ret;
1217                 }
1218
1219         ret = devm_request_irq(&pdev->dev, i2c->irq, s3c24xx_i2c_irq, 0,
1220                                 dev_name(&pdev->dev), i2c);
1221
1222                 if (ret != 0) {
1223                         dev_err(&pdev->dev, "cannot claim IRQ %d\n", i2c->irq);
1224                         clk_unprepare(i2c->clk);
1225                         return ret;
1226                 }
1227         }
1228
1229         ret = s3c24xx_i2c_register_cpufreq(i2c);
1230         if (ret < 0) {
1231                 dev_err(&pdev->dev, "failed to register cpufreq notifier\n");
1232                 clk_unprepare(i2c->clk);
1233                 return ret;
1234         }
1235
1236         /* Note, previous versions of the driver used i2c_add_adapter()
1237          * to add the bus at any number. We now pass the bus number via
1238          * the platform data, so if unset it will now default to always
1239          * being bus 0.
1240          */
1241
1242         i2c->adap.nr = i2c->pdata->bus_num;
1243         i2c->adap.dev.of_node = pdev->dev.of_node;
1244
1245         ret = i2c_add_numbered_adapter(&i2c->adap);
1246         if (ret < 0) {
1247                 dev_err(&pdev->dev, "failed to add bus to i2c core\n");
1248                 s3c24xx_i2c_deregister_cpufreq(i2c);
1249                 clk_unprepare(i2c->clk);
1250                 return ret;
1251         }
1252
1253         platform_set_drvdata(pdev, i2c);
1254
1255         pm_runtime_enable(&pdev->dev);
1256         pm_runtime_enable(&i2c->adap.dev);
1257
1258         dev_info(&pdev->dev, "%s: S3C I2C adapter\n", dev_name(&i2c->adap.dev));
1259         return 0;
1260 }
1261
1262 /* s3c24xx_i2c_remove
1263  *
1264  * called when device is removed from the bus
1265 */
1266
1267 static int s3c24xx_i2c_remove(struct platform_device *pdev)
1268 {
1269         struct s3c24xx_i2c *i2c = platform_get_drvdata(pdev);
1270
1271         clk_unprepare(i2c->clk);
1272
1273         pm_runtime_disable(&i2c->adap.dev);
1274         pm_runtime_disable(&pdev->dev);
1275
1276         s3c24xx_i2c_deregister_cpufreq(i2c);
1277
1278         i2c_del_adapter(&i2c->adap);
1279
1280         if (pdev->dev.of_node && IS_ERR(i2c->pctrl))
1281                 s3c24xx_i2c_dt_gpio_free(i2c);
1282
1283         return 0;
1284 }
1285
1286 #ifdef CONFIG_PM_SLEEP
1287 static int s3c24xx_i2c_suspend_noirq(struct device *dev)
1288 {
1289         struct platform_device *pdev = to_platform_device(dev);
1290         struct s3c24xx_i2c *i2c = platform_get_drvdata(pdev);
1291
1292         i2c->suspended = 1;
1293
1294         if (!IS_ERR(i2c->sysreg))
1295                 regmap_read(i2c->sysreg, EXYNOS5_SYS_I2C_CFG, &i2c->sys_i2c_cfg);
1296
1297         return 0;
1298 }
1299
1300 static int s3c24xx_i2c_resume_noirq(struct device *dev)
1301 {
1302         struct platform_device *pdev = to_platform_device(dev);
1303         struct s3c24xx_i2c *i2c = platform_get_drvdata(pdev);
1304         int ret;
1305
1306         if (!IS_ERR(i2c->sysreg))
1307                 regmap_write(i2c->sysreg, EXYNOS5_SYS_I2C_CFG, i2c->sys_i2c_cfg);
1308
1309         ret = clk_enable(i2c->clk);
1310         if (ret)
1311                 return ret;
1312         s3c24xx_i2c_init(i2c);
1313         clk_disable(i2c->clk);
1314         i2c->suspended = 0;
1315
1316         return 0;
1317 }
1318 #endif
1319
1320 #ifdef CONFIG_PM
1321 static const struct dev_pm_ops s3c24xx_i2c_dev_pm_ops = {
1322 #ifdef CONFIG_PM_SLEEP
1323         .suspend_noirq = s3c24xx_i2c_suspend_noirq,
1324         .resume_noirq = s3c24xx_i2c_resume_noirq,
1325         .freeze_noirq = s3c24xx_i2c_suspend_noirq,
1326         .thaw_noirq = s3c24xx_i2c_resume_noirq,
1327         .poweroff_noirq = s3c24xx_i2c_suspend_noirq,
1328         .restore_noirq = s3c24xx_i2c_resume_noirq,
1329 #endif
1330 };
1331
1332 #define S3C24XX_DEV_PM_OPS (&s3c24xx_i2c_dev_pm_ops)
1333 #else
1334 #define S3C24XX_DEV_PM_OPS NULL
1335 #endif
1336
1337 /* device driver for platform bus bits */
1338
1339 static struct platform_driver s3c24xx_i2c_driver = {
1340         .probe          = s3c24xx_i2c_probe,
1341         .remove         = s3c24xx_i2c_remove,
1342         .id_table       = s3c24xx_driver_ids,
1343         .driver         = {
1344                 .name   = "s3c-i2c",
1345                 .pm     = S3C24XX_DEV_PM_OPS,
1346                 .of_match_table = of_match_ptr(s3c24xx_i2c_match),
1347         },
1348 };
1349
1350 static int __init i2c_adap_s3c_init(void)
1351 {
1352         return platform_driver_register(&s3c24xx_i2c_driver);
1353 }
1354 subsys_initcall(i2c_adap_s3c_init);
1355
1356 static void __exit i2c_adap_s3c_exit(void)
1357 {
1358         platform_driver_unregister(&s3c24xx_i2c_driver);
1359 }
1360 module_exit(i2c_adap_s3c_exit);
1361
1362 MODULE_DESCRIPTION("S3C24XX I2C Bus driver");
1363 MODULE_AUTHOR("Ben Dooks, <ben@simtec.co.uk>");
1364 MODULE_LICENSE("GPL");