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 const 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                                         dev_dbg(i2c->dev,
 503                                                 "missing START before write->read\n");
 504                                         s3c24xx_i2c_stop(i2c, -EINVAL);
 505                                         break;
 506                                 }
 507
 508                                 goto retry_write;
 509                         } else {
 510                                 /* send the new start */
 511                                 s3c24xx_i2c_message_start(i2c, i2c->msg);
 512                                 i2c->state = STATE_START;
 513                         }
 514
 515                 } else {
 516                         /* send stop */
 517
 518                         s3c24xx_i2c_stop(i2c, 0);
 519                 }
 520                 break;
 521
 522         case STATE_READ:
 523                 /* we have a byte of data in the data register, do
 524                  * something with it, and then work out whether we are
 525                  * going to do any more read/write
 526                  */
 527
 528                 byte = readb(i2c->regs + S3C2410_IICDS);
 529                 i2c->msg->buf[i2c->msg_ptr++] = byte;
 530
 531                 /* Add actual length to read for smbus block read */
 532                 if (i2c->msg->flags & I2C_M_RECV_LEN && i2c->msg->len == 1)
 533                         i2c->msg->len += byte;
 534  prepare_read:
 535                 if (is_msglast(i2c)) {
 536                         /* last byte of buffer */
 537
 538                         if (is_lastmsg(i2c))
 539                                 s3c24xx_i2c_disable_ack(i2c);
 540
 541                 } else if (is_msgend(i2c)) {
 542                         /* ok, we've read the entire buffer, see if there
 543                          * is anything else we need to do */
 544
 545                         if (is_lastmsg(i2c)) {
 546                                 /* last message, send stop and complete */
 547                                 dev_dbg(i2c->dev, "READ: Send Stop\n");
 548
 549                                 s3c24xx_i2c_stop(i2c, 0);
 550                         } else {
 551                                 /* go to the next transfer */
 552                                 dev_dbg(i2c->dev, "READ: Next Transfer\n");
 553
 554                                 i2c->msg_ptr = 0;
 555                                 i2c->msg_idx++;
 556                                 i2c->msg++;
 557                         }
 558                 }
 559
 560                 break;
 561         }
 562
 563         /* acknowlegde the IRQ and get back on with the work */
 564
 565  out_ack:
 566         tmp = readl(i2c->regs + S3C2410_IICCON);
 567         tmp &= ~S3C2410_IICCON_IRQPEND;
 568         writel(tmp, i2c->regs + S3C2410_IICCON);
 569  out:
 570         return ret;
 571 }
 572
 573 /* s3c24xx_i2c_irq
 574  *
 575  * top level IRQ servicing routine
 576 */
 577
 578 static irqreturn_t s3c24xx_i2c_irq(int irqno, void *dev_id)
 579 {
 580         struct s3c24xx_i2c *i2c = dev_id;
 581         unsigned long status;
 582         unsigned long tmp;
 583
 584         status = readl(i2c->regs + S3C2410_IICSTAT);
 585
 586         if (status & S3C2410_IICSTAT_ARBITR) {
 587                 /* deal with arbitration loss */
 588                 dev_err(i2c->dev, "deal with arbitration loss\n");
 589         }
 590
 591         if (i2c->state == STATE_IDLE) {
 592                 dev_dbg(i2c->dev, "IRQ: error i2c->state == IDLE\n");
 593
 594                 tmp = readl(i2c->regs + S3C2410_IICCON);
 595                 tmp &= ~S3C2410_IICCON_IRQPEND;
 596                 writel(tmp, i2c->regs +  S3C2410_IICCON);
 597                 goto out;
 598         }
 599
 600         /* pretty much this leaves us with the fact that we've
 601          * transmitted or received whatever byte we last sent */
 602
 603         i2c_s3c_irq_nextbyte(i2c, status);
 604
 605  out:
 606         return IRQ_HANDLED;
 607 }
 608
 609 /*
 610  * Disable the bus so that we won't get any interrupts from now on, or try
 611  * to drive any lines. This is the default state when we don't have
 612  * anything to send/receive.
 613  *
 614  * If there is an event on the bus, or we have a pre-existing event at
 615  * kernel boot time, we may not notice the event and the I2C controller
 616  * will lock the bus with the I2C clock line low indefinitely.
 617  */
 618 static inline void s3c24xx_i2c_disable_bus(struct s3c24xx_i2c *i2c)
 619 {
 620         unsigned long tmp;
 621
 622         /* Stop driving the I2C pins */
 623         tmp = readl(i2c->regs + S3C2410_IICSTAT);
 624         tmp &= ~S3C2410_IICSTAT_TXRXEN;
 625         writel(tmp, i2c->regs + S3C2410_IICSTAT);
 626
 627         /* We don't expect any interrupts now, and don't want send acks */
 628         tmp = readl(i2c->regs + S3C2410_IICCON);
 629         tmp &= ~(S3C2410_IICCON_IRQEN | S3C2410_IICCON_IRQPEND |
 630                 S3C2410_IICCON_ACKEN);
 631         writel(tmp, i2c->regs + S3C2410_IICCON);
 632 }
 633
 634
 635 /* s3c24xx_i2c_set_master
 636  *
 637  * get the i2c bus for a master transaction
 638 */
 639
 640 static int s3c24xx_i2c_set_master(struct s3c24xx_i2c *i2c)
 641 {
 642         unsigned long iicstat;
 643         int timeout = 400;
 644
 645         while (timeout-- > 0) {
 646                 iicstat = readl(i2c->regs + S3C2410_IICSTAT);
 647
 648                 if (!(iicstat & S3C2410_IICSTAT_BUSBUSY))
 649                         return 0;
 650
 651                 msleep(1);
 652         }
 653
 654         return -ETIMEDOUT;
 655 }
 656
 657 /* s3c24xx_i2c_wait_idle
 658  *
 659  * wait for the i2c bus to become idle.
 660 */
 661
 662 static void s3c24xx_i2c_wait_idle(struct s3c24xx_i2c *i2c)
 663 {
 664         unsigned long iicstat;
 665         ktime_t start, now;
 666         unsigned long delay;
 667         int spins;
 668
 669         /* ensure the stop has been through the bus */
 670
 671         dev_dbg(i2c->dev, "waiting for bus idle\n");
 672
 673         start = now = ktime_get();
 674
 675         /*
 676          * Most of the time, the bus is already idle within a few usec of the
 677          * end of a transaction.  However, really slow i2c devices can stretch
 678          * the clock, delaying STOP generation.
 679          *
 680          * On slower SoCs this typically happens within a very small number of
 681          * instructions so busy wait briefly to avoid scheduling overhead.
 682          */
 683         spins = 3;
 684         iicstat = readl(i2c->regs + S3C2410_IICSTAT);
 685         while ((iicstat & S3C2410_IICSTAT_START) && --spins) {
 686                 cpu_relax();
 687                 iicstat = readl(i2c->regs + S3C2410_IICSTAT);
 688         }
 689
 690         /*
 691          * If we do get an appreciable delay as a compromise between idle
 692          * detection latency for the normal, fast case, and system load in the
 693          * slow device case, use an exponential back off in the polling loop,
 694          * up to 1/10th of the total timeout, then continue to poll at a
 695          * constant rate up to the timeout.
 696          */
 697         delay = 1;
 698         while ((iicstat & S3C2410_IICSTAT_START) &&
 699                ktime_us_delta(now, start) < S3C2410_IDLE_TIMEOUT) {
 700                 usleep_range(delay, 2 * delay);
 701                 if (delay < S3C2410_IDLE_TIMEOUT / 10)
 702                         delay <<= 1;
 703                 now = ktime_get();
 704                 iicstat = readl(i2c->regs + S3C2410_IICSTAT);
 705         }
 706
 707         if (iicstat & S3C2410_IICSTAT_START)
 708                 dev_warn(i2c->dev, "timeout waiting for bus idle\n");
 709 }
 710
 711 /* s3c24xx_i2c_doxfer
 712  *
 713  * this starts an i2c transfer
 714 */
 715
 716 static int s3c24xx_i2c_doxfer(struct s3c24xx_i2c *i2c,
 717                               struct i2c_msg *msgs, int num)
 718 {
 719         unsigned long timeout;
 720         int ret;
 721
 722         if (i2c->suspended)
 723                 return -EIO;
 724
 725         ret = s3c24xx_i2c_set_master(i2c);
 726         if (ret != 0) {
 727                 dev_err(i2c->dev, "cannot get bus (error %d)\n", ret);
 728                 ret = -EAGAIN;
 729                 goto out;
 730         }
 731
 732         i2c->msg     = msgs;
 733         i2c->msg_num = num;
 734         i2c->msg_ptr = 0;
 735         i2c->msg_idx = 0;
 736         i2c->state   = STATE_START;
 737
 738         s3c24xx_i2c_enable_irq(i2c);
 739         s3c24xx_i2c_message_start(i2c, msgs);
 740
 741         if (i2c->quirks & QUIRK_POLL) {
 742                 ret = i2c->msg_idx;
 743
 744                 if (ret != num)
 745                         dev_dbg(i2c->dev, "incomplete xfer (%d)\n", ret);
 746
 747                 goto out;
 748         }
 749
 750         timeout = wait_event_timeout(i2c->wait, i2c->msg_num == 0, HZ * 5);
 751
 752         ret = i2c->msg_idx;
 753
 754         /* having these next two as dev_err() makes life very
 755          * noisy when doing an i2cdetect */
 756
 757         if (timeout == 0)
 758                 dev_dbg(i2c->dev, "timeout\n");
 759         else if (ret != num)
 760                 dev_dbg(i2c->dev, "incomplete xfer (%d)\n", ret);
 761
 762         /* For QUIRK_HDMIPHY, bus is already disabled */
 763         if (i2c->quirks & QUIRK_HDMIPHY)
 764                 goto out;
 765
 766         s3c24xx_i2c_wait_idle(i2c);
 767
 768         s3c24xx_i2c_disable_bus(i2c);
 769
 770  out:
 771         i2c->state = STATE_IDLE;
 772
 773         return ret;
 774 }
 775
 776 /* s3c24xx_i2c_xfer
 777  *
 778  * first port of call from the i2c bus code when an message needs
 779  * transferring across the i2c bus.
 780 */
 781
 782 static int s3c24xx_i2c_xfer(struct i2c_adapter *adap,
 783                         struct i2c_msg *msgs, int num)
 784 {
 785         struct s3c24xx_i2c *i2c = (struct s3c24xx_i2c *)adap->algo_data;
 786         int retry;
 787         int ret;
 788
 789         pm_runtime_get_sync(&adap->dev);
 790         ret = clk_enable(i2c->clk);
 791         if (ret)
 792                 return ret;
 793
 794         for (retry = 0; retry < adap->retries; retry++) {
 795
 796                 ret = s3c24xx_i2c_doxfer(i2c, msgs, num);
 797
 798                 if (ret != -EAGAIN) {
 799                         clk_disable(i2c->clk);
 800                         pm_runtime_put(&adap->dev);
 801                         return ret;
 802                 }
 803
 804                 dev_dbg(i2c->dev, "Retrying transmission (%d)\n", retry);
 805
 806                 udelay(100);
 807         }
 808
 809         clk_disable(i2c->clk);
 810         pm_runtime_put(&adap->dev);
 811         return -EREMOTEIO;
 812 }
 813
 814 /* declare our i2c functionality */
 815 static u32 s3c24xx_i2c_func(struct i2c_adapter *adap)
 816 {
 817         return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_NOSTART |
 818                 I2C_FUNC_PROTOCOL_MANGLING;
 819 }
 820
 821 /* i2c bus registration info */
 822
 823 static const struct i2c_algorithm s3c24xx_i2c_algorithm = {
 824         .master_xfer            = s3c24xx_i2c_xfer,
 825         .functionality          = s3c24xx_i2c_func,
 826 };
 827
 828 /* s3c24xx_i2c_calcdivisor
 829  *
 830  * return the divisor settings for a given frequency
 831 */
 832
 833 static int s3c24xx_i2c_calcdivisor(unsigned long clkin, unsigned int wanted,
 834                                    unsigned int *div1, unsigned int *divs)
 835 {
 836         unsigned int calc_divs = clkin / wanted;
 837         unsigned int calc_div1;
 838
 839         if (calc_divs > (16*16))
 840                 calc_div1 = 512;
 841         else
 842                 calc_div1 = 16;
 843
 844         calc_divs += calc_div1-1;
 845         calc_divs /= calc_div1;
 846
 847         if (calc_divs == 0)
 848                 calc_divs = 1;
 849         if (calc_divs > 17)
 850                 calc_divs = 17;
 851
 852         *divs = calc_divs;
 853         *div1 = calc_div1;
 854
 855         return clkin / (calc_divs * calc_div1);
 856 }
 857
 858 /* s3c24xx_i2c_clockrate
 859  *
 860  * work out a divisor for the user requested frequency setting,
 861  * either by the requested frequency, or scanning the acceptable
 862  * range of frequencies until something is found
 863 */
 864
 865 static int s3c24xx_i2c_clockrate(struct s3c24xx_i2c *i2c, unsigned int *got)
 866 {
 867         struct s3c2410_platform_i2c *pdata = i2c->pdata;
 868         unsigned long clkin = clk_get_rate(i2c->clk);
 869         unsigned int divs, div1;
 870         unsigned long target_frequency;
 871         u32 iiccon;
 872         int freq;
 873
 874         i2c->clkrate = clkin;
 875         clkin /= 1000;          /* clkin now in KHz */
 876
 877         dev_dbg(i2c->dev, "pdata desired frequency %lu\n", pdata->frequency);
 878
 879         target_frequency = pdata->frequency ? pdata->frequency : 100000;
 880
 881         target_frequency /= 1000; /* Target frequency now in KHz */
 882
 883         freq = s3c24xx_i2c_calcdivisor(clkin, target_frequency, &div1, &divs);
 884
 885         if (freq > target_frequency) {
 886                 dev_err(i2c->dev,
 887                         "Unable to achieve desired frequency %luKHz."   \
 888                         " Lowest achievable %dKHz\n", target_frequency, freq);
 889                 return -EINVAL;
 890         }
 891
 892         *got = freq;
 893
 894         iiccon = readl(i2c->regs + S3C2410_IICCON);
 895         iiccon &= ~(S3C2410_IICCON_SCALEMASK | S3C2410_IICCON_TXDIV_512);
 896         iiccon |= (divs-1);
 897
 898         if (div1 == 512)
 899                 iiccon |= S3C2410_IICCON_TXDIV_512;
 900
 901         if (i2c->quirks & QUIRK_POLL)
 902                 iiccon |= S3C2410_IICCON_SCALE(2);
 903
 904         writel(iiccon, i2c->regs + S3C2410_IICCON);
 905
 906         if (i2c->quirks & QUIRK_S3C2440) {
 907                 unsigned long sda_delay;
 908
 909                 if (pdata->sda_delay) {
 910                         sda_delay = clkin * pdata->sda_delay;
 911                         sda_delay = DIV_ROUND_UP(sda_delay, 1000000);
 912                         sda_delay = DIV_ROUND_UP(sda_delay, 5);
 913                         if (sda_delay > 3)
 914                                 sda_delay = 3;
 915                         sda_delay |= S3C2410_IICLC_FILTER_ON;
 916                 } else
 917                         sda_delay = 0;
 918
 919                 dev_dbg(i2c->dev, "IICLC=%08lx\n", sda_delay);
 920                 writel(sda_delay, i2c->regs + S3C2440_IICLC);
 921         }
 922
 923         return 0;
 924 }
 925
 926 #if defined(CONFIG_ARM_S3C24XX_CPUFREQ)
 927
 928 #define freq_to_i2c(_n) container_of(_n, struct s3c24xx_i2c, freq_transition)
 929
 930 static int s3c24xx_i2c_cpufreq_transition(struct notifier_block *nb,
 931                                           unsigned long val, void *data)
 932 {
 933         struct s3c24xx_i2c *i2c = freq_to_i2c(nb);
 934         unsigned int got;
 935         int delta_f;
 936         int ret;
 937
 938         delta_f = clk_get_rate(i2c->clk) - i2c->clkrate;
 939
 940         /* if we're post-change and the input clock has slowed down
 941          * or at pre-change and the clock is about to speed up, then
 942          * adjust our clock rate. <0 is slow, >0 speedup.
 943          */
 944
 945         if ((val == CPUFREQ_POSTCHANGE && delta_f < 0) ||
 946             (val == CPUFREQ_PRECHANGE && delta_f > 0)) {
 947                 i2c_lock_adapter(&i2c->adap);
 948                 ret = s3c24xx_i2c_clockrate(i2c, &got);
 949                 i2c_unlock_adapter(&i2c->adap);
 950
 951                 if (ret < 0)
 952                         dev_err(i2c->dev, "cannot find frequency\n");
 953                 else
 954                         dev_info(i2c->dev, "setting freq %d\n", got);
 955         }
 956
 957         return 0;
 958 }
 959
 960 static inline int s3c24xx_i2c_register_cpufreq(struct s3c24xx_i2c *i2c)
 961 {
 962         i2c->freq_transition.notifier_call = s3c24xx_i2c_cpufreq_transition;
 963
 964         return cpufreq_register_notifier(&i2c->freq_transition,
 965                                          CPUFREQ_TRANSITION_NOTIFIER);
 966 }
 967
 968 static inline void s3c24xx_i2c_deregister_cpufreq(struct s3c24xx_i2c *i2c)
 969 {
 970         cpufreq_unregister_notifier(&i2c->freq_transition,
 971                                     CPUFREQ_TRANSITION_NOTIFIER);
 972 }
 973
 974 #else
 975 static inline int s3c24xx_i2c_register_cpufreq(struct s3c24xx_i2c *i2c)
 976 {
 977         return 0;
 978 }
 979
 980 static inline void s3c24xx_i2c_deregister_cpufreq(struct s3c24xx_i2c *i2c)
 981 {
 982 }
 983 #endif
 984
 985 #ifdef CONFIG_OF
 986 static int s3c24xx_i2c_parse_dt_gpio(struct s3c24xx_i2c *i2c)
 987 {
 988         int idx, gpio, ret;
 989
 990         if (i2c->quirks & QUIRK_NO_GPIO)
 991                 return 0;
 992
 993         for (idx = 0; idx < 2; idx++) {
 994                 gpio = of_get_gpio(i2c->dev->of_node, idx);
 995                 if (!gpio_is_valid(gpio)) {
 996                         dev_err(i2c->dev, "invalid gpio[%d]: %d\n", idx, gpio);
 997                         goto free_gpio;
 998                 }
 999                 i2c->gpios[idx] = gpio;
1000
1001                 ret = gpio_request(gpio, "i2c-bus");
1002                 if (ret) {
1003                         dev_err(i2c->dev, "gpio [%d] request failed\n", gpio);
1004                         goto free_gpio;
1005                 }
1006         }
1007         return 0;
1008
1009 free_gpio:
1010         while (--idx >= 0)
1011                 gpio_free(i2c->gpios[idx]);
1012         return -EINVAL;
1013 }
1014
1015 static void s3c24xx_i2c_dt_gpio_free(struct s3c24xx_i2c *i2c)
1016 {
1017         unsigned int idx;
1018
1019         if (i2c->quirks & QUIRK_NO_GPIO)
1020                 return;
1021
1022         for (idx = 0; idx < 2; idx++)
1023                 gpio_free(i2c->gpios[idx]);
1024 }
1025 #else
1026 static int s3c24xx_i2c_parse_dt_gpio(struct s3c24xx_i2c *i2c)
1027 {
1028         return 0;
1029 }
1030
1031 static void s3c24xx_i2c_dt_gpio_free(struct s3c24xx_i2c *i2c)
1032 {
1033 }
1034 #endif
1035
1036 /* s3c24xx_i2c_init
1037  *
1038  * initialise the controller, set the IO lines and frequency
1039 */
1040
1041 static int s3c24xx_i2c_init(struct s3c24xx_i2c *i2c)
1042 {
1043         struct s3c2410_platform_i2c *pdata;
1044         unsigned int freq;
1045
1046         /* get the plafrom data */
1047
1048         pdata = i2c->pdata;
1049
1050         /* write slave address */
1051
1052         writeb(pdata->slave_addr, i2c->regs + S3C2410_IICADD);
1053
1054         dev_info(i2c->dev, "slave address 0x%02x\n", pdata->slave_addr);
1055
1056         writel(0, i2c->regs + S3C2410_IICCON);
1057         writel(0, i2c->regs + S3C2410_IICSTAT);
1058
1059         /* we need to work out the divisors for the clock... */
1060
1061         if (s3c24xx_i2c_clockrate(i2c, &freq) != 0) {
1062                 dev_err(i2c->dev, "cannot meet bus frequency required\n");
1063                 return -EINVAL;
1064         }
1065
1066         /* todo - check that the i2c lines aren't being dragged anywhere */
1067
1068         dev_info(i2c->dev, "bus frequency set to %d KHz\n", freq);
1069         dev_dbg(i2c->dev, "S3C2410_IICCON=0x%02x\n",
1070                 readl(i2c->regs + S3C2410_IICCON));
1071
1072         return 0;
1073 }
1074
1075 #ifdef CONFIG_OF
1076 /* s3c24xx_i2c_parse_dt
1077  *
1078  * Parse the device tree node and retreive the platform data.
1079 */
1080
1081 static void
1082 s3c24xx_i2c_parse_dt(struct device_node *np, struct s3c24xx_i2c *i2c)
1083 {
1084         struct s3c2410_platform_i2c *pdata = i2c->pdata;
1085         int id;
1086
1087         if (!np)
1088                 return;
1089
1090         pdata->bus_num = -1; /* i2c bus number is dynamically assigned */
1091         of_property_read_u32(np, "samsung,i2c-sda-delay", &pdata->sda_delay);
1092         of_property_read_u32(np, "samsung,i2c-slave-addr", &pdata->slave_addr);
1093         of_property_read_u32(np, "samsung,i2c-max-bus-freq",
1094                                 (u32 *)&pdata->frequency);
1095         /*
1096          * Exynos5's legacy i2c controller and new high speed i2c
1097          * controller have muxed interrupt sources. By default the
1098          * interrupts for 4-channel HS-I2C controller are enabled.
1099          * If nodes for first four channels of legacy i2c controller
1100          * are available then re-configure the interrupts via the
1101          * system register.
1102          */
1103         id = of_alias_get_id(np, "i2c");
1104         i2c->sysreg = syscon_regmap_lookup_by_phandle(np,
1105                         "samsung,sysreg-phandle");
1106         if (IS_ERR(i2c->sysreg))
1107                 return;
1108
1109         regmap_update_bits(i2c->sysreg, EXYNOS5_SYS_I2C_CFG, BIT(id), 0);
1110 }
1111 #else
1112 static void
1113 s3c24xx_i2c_parse_dt(struct device_node *np, struct s3c24xx_i2c *i2c)
1114 {
1115         return;
1116 }
1117 #endif
1118
1119 /* s3c24xx_i2c_probe
1120  *
1121  * called by the bus driver when a suitable device is found
1122 */
1123
1124 static int s3c24xx_i2c_probe(struct platform_device *pdev)
1125 {
1126         struct s3c24xx_i2c *i2c;
1127         struct s3c2410_platform_i2c *pdata = NULL;
1128         struct resource *res;
1129         int ret;
1130
1131         if (!pdev->dev.of_node) {
1132                 pdata = dev_get_platdata(&pdev->dev);
1133                 if (!pdata) {
1134                         dev_err(&pdev->dev, "no platform data\n");
1135                         return -EINVAL;
1136                 }
1137         }
1138
1139         i2c = devm_kzalloc(&pdev->dev, sizeof(struct s3c24xx_i2c), GFP_KERNEL);
1140         if (!i2c)
1141                 return -ENOMEM;
1142
1143         i2c->pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
1144         if (!i2c->pdata)
1145                 return -ENOMEM;
1146
1147         i2c->quirks = s3c24xx_get_device_quirks(pdev);
1148         i2c->sysreg = ERR_PTR(-ENOENT);
1149         if (pdata)
1150                 memcpy(i2c->pdata, pdata, sizeof(*pdata));
1151         else
1152                 s3c24xx_i2c_parse_dt(pdev->dev.of_node, i2c);
1153
1154         strlcpy(i2c->adap.name, "s3c2410-i2c", sizeof(i2c->adap.name));
1155         i2c->adap.owner = THIS_MODULE;
1156         i2c->adap.algo = &s3c24xx_i2c_algorithm;
1157         i2c->adap.retries = 2;
1158         i2c->adap.class = I2C_CLASS_DEPRECATED;
1159         i2c->tx_setup = 50;
1160
1161         init_waitqueue_head(&i2c->wait);
1162
1163         /* find the clock and enable it */
1164
1165         i2c->dev = &pdev->dev;
1166         i2c->clk = devm_clk_get(&pdev->dev, "i2c");
1167         if (IS_ERR(i2c->clk)) {
1168                 dev_err(&pdev->dev, "cannot get clock\n");
1169                 return -ENOENT;
1170         }
1171
1172         dev_dbg(&pdev->dev, "clock source %p\n", i2c->clk);
1173
1174
1175         /* map the registers */
1176
1177         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1178         i2c->regs = devm_ioremap_resource(&pdev->dev, res);
1179
1180         if (IS_ERR(i2c->regs))
1181                 return PTR_ERR(i2c->regs);
1182
1183         dev_dbg(&pdev->dev, "registers %p (%p)\n",
1184                 i2c->regs, res);
1185
1186         /* setup info block for the i2c core */
1187
1188         i2c->adap.algo_data = i2c;
1189         i2c->adap.dev.parent = &pdev->dev;
1190
1191         i2c->pctrl = devm_pinctrl_get_select_default(i2c->dev);
1192
1193         /* inititalise the i2c gpio lines */
1194
1195         if (i2c->pdata->cfg_gpio) {
1196                 i2c->pdata->cfg_gpio(to_platform_device(i2c->dev));
1197         } else if (IS_ERR(i2c->pctrl) && s3c24xx_i2c_parse_dt_gpio(i2c)) {
1198                 return -EINVAL;
1199         }
1200
1201         /* initialise the i2c controller */
1202
1203         clk_prepare_enable(i2c->clk);
1204         ret = s3c24xx_i2c_init(i2c);
1205         clk_disable(i2c->clk);
1206         if (ret != 0) {
1207                 dev_err(&pdev->dev, "I2C controller init failed\n");
1208                 return ret;
1209         }
1210         /* find the IRQ for this unit (note, this relies on the init call to
1211          * ensure no current IRQs pending
1212          */
1213
1214         if (!(i2c->quirks & QUIRK_POLL)) {
1215                 i2c->irq = ret = platform_get_irq(pdev, 0);
1216                 if (ret < 0) {
1217                         dev_err(&pdev->dev, "cannot find IRQ\n");
1218                         clk_unprepare(i2c->clk);
1219                         return ret;
1220                 }
1221
1222         ret = devm_request_irq(&pdev->dev, i2c->irq, s3c24xx_i2c_irq, 0,
1223                                 dev_name(&pdev->dev), i2c);
1224
1225                 if (ret != 0) {
1226                         dev_err(&pdev->dev, "cannot claim IRQ %d\n", i2c->irq);
1227                         clk_unprepare(i2c->clk);
1228                         return ret;
1229                 }
1230         }
1231
1232         ret = s3c24xx_i2c_register_cpufreq(i2c);
1233         if (ret < 0) {
1234                 dev_err(&pdev->dev, "failed to register cpufreq notifier\n");
1235                 clk_unprepare(i2c->clk);
1236                 return ret;
1237         }
1238
1239         /* Note, previous versions of the driver used i2c_add_adapter()
1240          * to add the bus at any number. We now pass the bus number via
1241          * the platform data, so if unset it will now default to always
1242          * being bus 0.
1243          */
1244
1245         i2c->adap.nr = i2c->pdata->bus_num;
1246         i2c->adap.dev.of_node = pdev->dev.of_node;
1247
1248         platform_set_drvdata(pdev, i2c);
1249
1250         pm_runtime_enable(&pdev->dev);
1251
1252         ret = i2c_add_numbered_adapter(&i2c->adap);
1253         if (ret < 0) {
1254                 dev_err(&pdev->dev, "failed to add bus to i2c core\n");
1255                 pm_runtime_disable(&pdev->dev);
1256                 s3c24xx_i2c_deregister_cpufreq(i2c);
1257                 clk_unprepare(i2c->clk);
1258                 return ret;
1259         }
1260
1261         pm_runtime_enable(&i2c->adap.dev);
1262
1263         dev_info(&pdev->dev, "%s: S3C I2C adapter\n", dev_name(&i2c->adap.dev));
1264         return 0;
1265 }
1266
1267 /* s3c24xx_i2c_remove
1268  *
1269  * called when device is removed from the bus
1270 */
1271
1272 static int s3c24xx_i2c_remove(struct platform_device *pdev)
1273 {
1274         struct s3c24xx_i2c *i2c = platform_get_drvdata(pdev);
1275
1276         clk_unprepare(i2c->clk);
1277
1278         pm_runtime_disable(&i2c->adap.dev);
1279         pm_runtime_disable(&pdev->dev);
1280
1281         s3c24xx_i2c_deregister_cpufreq(i2c);
1282
1283         i2c_del_adapter(&i2c->adap);
1284
1285         if (pdev->dev.of_node && IS_ERR(i2c->pctrl))
1286                 s3c24xx_i2c_dt_gpio_free(i2c);
1287
1288         return 0;
1289 }
1290
1291 #ifdef CONFIG_PM_SLEEP
1292 static int s3c24xx_i2c_suspend_noirq(struct device *dev)
1293 {
1294         struct platform_device *pdev = to_platform_device(dev);
1295         struct s3c24xx_i2c *i2c = platform_get_drvdata(pdev);
1296
1297         i2c->suspended = 1;
1298
1299         if (!IS_ERR(i2c->sysreg))
1300                 regmap_read(i2c->sysreg, EXYNOS5_SYS_I2C_CFG, &i2c->sys_i2c_cfg);
1301
1302         return 0;
1303 }
1304
1305 static int s3c24xx_i2c_resume_noirq(struct device *dev)
1306 {
1307         struct platform_device *pdev = to_platform_device(dev);
1308         struct s3c24xx_i2c *i2c = platform_get_drvdata(pdev);
1309         int ret;
1310
1311         if (!IS_ERR(i2c->sysreg))
1312                 regmap_write(i2c->sysreg, EXYNOS5_SYS_I2C_CFG, i2c->sys_i2c_cfg);
1313
1314         ret = clk_enable(i2c->clk);
1315         if (ret)
1316                 return ret;
1317         s3c24xx_i2c_init(i2c);
1318         clk_disable(i2c->clk);
1319         i2c->suspended = 0;
1320
1321         return 0;
1322 }
1323 #endif
1324
1325 #ifdef CONFIG_PM
1326 static const struct dev_pm_ops s3c24xx_i2c_dev_pm_ops = {
1327 #ifdef CONFIG_PM_SLEEP
1328         .suspend_noirq = s3c24xx_i2c_suspend_noirq,
1329         .resume_noirq = s3c24xx_i2c_resume_noirq,
1330         .freeze_noirq = s3c24xx_i2c_suspend_noirq,
1331         .thaw_noirq = s3c24xx_i2c_resume_noirq,
1332         .poweroff_noirq = s3c24xx_i2c_suspend_noirq,
1333         .restore_noirq = s3c24xx_i2c_resume_noirq,
1334 #endif
1335 };
1336
1337 #define S3C24XX_DEV_PM_OPS (&s3c24xx_i2c_dev_pm_ops)
1338 #else
1339 #define S3C24XX_DEV_PM_OPS NULL
1340 #endif
1341
1342 /* device driver for platform bus bits */
1343
1344 static struct platform_driver s3c24xx_i2c_driver = {
1345         .probe          = s3c24xx_i2c_probe,
1346         .remove         = s3c24xx_i2c_remove,
1347         .id_table       = s3c24xx_driver_ids,
1348         .driver         = {
1349                 .name   = "s3c-i2c",
1350                 .pm     = S3C24XX_DEV_PM_OPS,
1351                 .of_match_table = of_match_ptr(s3c24xx_i2c_match),
1352         },
1353 };
1354
1355 static int __init i2c_adap_s3c_init(void)
1356 {
1357         return platform_driver_register(&s3c24xx_i2c_driver);
1358 }
1359 subsys_initcall(i2c_adap_s3c_init);
1360
1361 static void __exit i2c_adap_s3c_exit(void)
1362 {
1363         platform_driver_unregister(&s3c24xx_i2c_driver);
1364 }
1365 module_exit(i2c_adap_s3c_exit);
1366
1367 MODULE_DESCRIPTION("S3C24XX I2C Bus driver");
1368 MODULE_AUTHOR("Ben Dooks, <ben@simtec.co.uk>");
1369 MODULE_LICENSE("GPL");