drivers/i2c/busses/i2c-s3c2410.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /* linux/drivers/i2c/busses/i2c-s3c2410.c
   3  *
   4  * Copyright (C) 2004,2005,2009 Simtec Electronics
   5  *      Ben Dooks <ben@simtec.co.uk>
   6  *
   7  * S3C2410 I2C Controller
   8 */
   9
  10 #include <linux/kernel.h>
  11 #include <linux/module.h>
  12
  13 #include <linux/i2c.h>
  14 #include <linux/init.h>
  15 #include <linux/time.h>
  16 #include <linux/interrupt.h>
  17 #include <linux/delay.h>
  18 #include <linux/errno.h>
  19 #include <linux/err.h>
  20 #include <linux/platform_device.h>
  21 #include <linux/pm_runtime.h>
  22 #include <linux/clk.h>
  23 #include <linux/cpufreq.h>
  24 #include <linux/slab.h>
  25 #include <linux/io.h>
  26 #include <linux/of.h>
  27 #include <linux/of_device.h>
  28 #include <linux/gpio/consumer.h>
  29 #include <linux/pinctrl/consumer.h>
  30 #include <linux/mfd/syscon.h>
  31 #include <linux/regmap.h>
  32
  33 #include <asm/irq.h>
  34
  35 #include <linux/platform_data/i2c-s3c2410.h>
  36
  37 /* see s3c2410x user guide, v1.1, section 9 (p447) for more info */
  38
  39 #define S3C2410_IICCON                  0x00
  40 #define S3C2410_IICSTAT                 0x04
  41 #define S3C2410_IICADD                  0x08
  42 #define S3C2410_IICDS                   0x0C
  43 #define S3C2440_IICLC                   0x10
  44
  45 #define S3C2410_IICCON_ACKEN            (1 << 7)
  46 #define S3C2410_IICCON_TXDIV_16         (0 << 6)
  47 #define S3C2410_IICCON_TXDIV_512        (1 << 6)
  48 #define S3C2410_IICCON_IRQEN            (1 << 5)
  49 #define S3C2410_IICCON_IRQPEND          (1 << 4)
  50 #define S3C2410_IICCON_SCALE(x)         ((x) & 0xf)
  51 #define S3C2410_IICCON_SCALEMASK        (0xf)
  52
  53 #define S3C2410_IICSTAT_MASTER_RX       (2 << 6)
  54 #define S3C2410_IICSTAT_MASTER_TX       (3 << 6)
  55 #define S3C2410_IICSTAT_SLAVE_RX        (0 << 6)
  56 #define S3C2410_IICSTAT_SLAVE_TX        (1 << 6)
  57 #define S3C2410_IICSTAT_MODEMASK        (3 << 6)
  58
  59 #define S3C2410_IICSTAT_START           (1 << 5)
  60 #define S3C2410_IICSTAT_BUSBUSY         (1 << 5)
  61 #define S3C2410_IICSTAT_TXRXEN          (1 << 4)
  62 #define S3C2410_IICSTAT_ARBITR          (1 << 3)
  63 #define S3C2410_IICSTAT_ASSLAVE         (1 << 2)
  64 #define S3C2410_IICSTAT_ADDR0           (1 << 1)
  65 #define S3C2410_IICSTAT_LASTBIT         (1 << 0)
  66
  67 #define S3C2410_IICLC_SDA_DELAY0        (0 << 0)
  68 #define S3C2410_IICLC_SDA_DELAY5        (1 << 0)
  69 #define S3C2410_IICLC_SDA_DELAY10       (2 << 0)
  70 #define S3C2410_IICLC_SDA_DELAY15       (3 << 0)
  71 #define S3C2410_IICLC_SDA_DELAY_MASK    (3 << 0)
  72
  73 #define S3C2410_IICLC_FILTER_ON         (1 << 2)
  74
  75 /* Treat S3C2410 as baseline hardware, anything else is supported via quirks */
  76 #define QUIRK_S3C2440           (1 << 0)
  77 #define QUIRK_HDMIPHY           (1 << 1)
  78 #define QUIRK_NO_GPIO           (1 << 2)
  79 #define QUIRK_POLL              (1 << 3)
  80
  81 /* Max time to wait for bus to become idle after a xfer (in us) */
  82 #define S3C2410_IDLE_TIMEOUT    5000
  83
  84 /* Exynos5 Sysreg offset */
  85 #define EXYNOS5_SYS_I2C_CFG     0x0234
  86
  87 /* i2c controller state */
  88 enum s3c24xx_i2c_state {
  89         STATE_IDLE,
  90         STATE_START,
  91         STATE_READ,
  92         STATE_WRITE,
  93         STATE_STOP
  94 };
  95
  96 struct s3c24xx_i2c {
  97         wait_queue_head_t       wait;
  98         kernel_ulong_t          quirks;
  99
 100         struct i2c_msg          *msg;
 101         unsigned int            msg_num;
 102         unsigned int            msg_idx;
 103         unsigned int            msg_ptr;
 104
 105         unsigned int            tx_setup;
 106         unsigned int            irq;
 107
 108         enum s3c24xx_i2c_state  state;
 109         unsigned long           clkrate;
 110
 111         void __iomem            *regs;
 112         struct clk              *clk;
 113         struct device           *dev;
 114         struct i2c_adapter      adap;
 115
 116         struct s3c2410_platform_i2c     *pdata;
 117         struct gpio_desc        *gpios[2];
 118         struct pinctrl          *pctrl;
 119         struct regmap           *sysreg;
 120         unsigned int            sys_i2c_cfg;
 121 };
 122
 123 static const struct platform_device_id s3c24xx_driver_ids[] = {
 124         {
 125                 .name           = "s3c2410-i2c",
 126                 .driver_data    = 0,
 127         }, {
 128                 .name           = "s3c2440-i2c",
 129                 .driver_data    = QUIRK_S3C2440,
 130         }, {
 131                 .name           = "s3c2440-hdmiphy-i2c",
 132                 .driver_data    = QUIRK_S3C2440 | QUIRK_HDMIPHY | QUIRK_NO_GPIO,
 133         }, { },
 134 };
 135 MODULE_DEVICE_TABLE(platform, s3c24xx_driver_ids);
 136
 137 static int i2c_s3c_irq_nextbyte(struct s3c24xx_i2c *i2c, unsigned long iicstat);
 138
 139 #ifdef CONFIG_OF
 140 static const struct of_device_id s3c24xx_i2c_match[] = {
 141         { .compatible = "samsung,s3c2410-i2c", .data = (void *)0 },
 142         { .compatible = "samsung,s3c2440-i2c", .data = (void *)QUIRK_S3C2440 },
 143         { .compatible = "samsung,s3c2440-hdmiphy-i2c",
 144           .data = (void *)(QUIRK_S3C2440 | QUIRK_HDMIPHY | QUIRK_NO_GPIO) },
 145         { .compatible = "samsung,exynos5-sata-phy-i2c",
 146           .data = (void *)(QUIRK_S3C2440 | QUIRK_POLL | QUIRK_NO_GPIO) },
 147         {},
 148 };
 149 MODULE_DEVICE_TABLE(of, s3c24xx_i2c_match);
 150 #endif
 151
 152 /*
 153  * Get controller type either from device tree or platform device variant.
 154  */
 155 static inline kernel_ulong_t s3c24xx_get_device_quirks(struct platform_device *pdev)
 156 {
 157         if (pdev->dev.of_node)
 158                 return (kernel_ulong_t)of_device_get_match_data(&pdev->dev);
 159
 160         return platform_get_device_id(pdev)->driver_data;
 161 }
 162
 163 /*
 164  * Complete the message and wake up the caller, using the given return code,
 165  * or zero to mean ok.
 166  */
 167 static inline void s3c24xx_i2c_master_complete(struct s3c24xx_i2c *i2c, int ret)
 168 {
 169         dev_dbg(i2c->dev, "master_complete %d\n", ret);
 170
 171         i2c->msg_ptr = 0;
 172         i2c->msg = NULL;
 173         i2c->msg_idx++;
 174         i2c->msg_num = 0;
 175         if (ret)
 176                 i2c->msg_idx = ret;
 177
 178         if (!(i2c->quirks & QUIRK_POLL))
 179                 wake_up(&i2c->wait);
 180 }
 181
 182 static inline void s3c24xx_i2c_disable_ack(struct s3c24xx_i2c *i2c)
 183 {
 184         unsigned long tmp;
 185
 186         tmp = readl(i2c->regs + S3C2410_IICCON);
 187         writel(tmp & ~S3C2410_IICCON_ACKEN, i2c->regs + S3C2410_IICCON);
 188 }
 189
 190 static inline void s3c24xx_i2c_enable_ack(struct s3c24xx_i2c *i2c)
 191 {
 192         unsigned long tmp;
 193
 194         tmp = readl(i2c->regs + S3C2410_IICCON);
 195         writel(tmp | S3C2410_IICCON_ACKEN, i2c->regs + S3C2410_IICCON);
 196 }
 197
 198 /* irq enable/disable functions */
 199 static inline void s3c24xx_i2c_disable_irq(struct s3c24xx_i2c *i2c)
 200 {
 201         unsigned long tmp;
 202
 203         tmp = readl(i2c->regs + S3C2410_IICCON);
 204         writel(tmp & ~S3C2410_IICCON_IRQEN, i2c->regs + S3C2410_IICCON);
 205 }
 206
 207 static inline void s3c24xx_i2c_enable_irq(struct s3c24xx_i2c *i2c)
 208 {
 209         unsigned long tmp;
 210
 211         tmp = readl(i2c->regs + S3C2410_IICCON);
 212         writel(tmp | S3C2410_IICCON_IRQEN, i2c->regs + S3C2410_IICCON);
 213 }
 214
 215 static bool is_ack(struct s3c24xx_i2c *i2c)
 216 {
 217         int tries;
 218
 219         for (tries = 50; tries; --tries) {
 220                 if (readl(i2c->regs + S3C2410_IICCON)
 221                         & S3C2410_IICCON_IRQPEND) {
 222                         if (!(readl(i2c->regs + S3C2410_IICSTAT)
 223                                 & S3C2410_IICSTAT_LASTBIT))
 224                                 return true;
 225                 }
 226                 usleep_range(1000, 2000);
 227         }
 228         dev_err(i2c->dev, "ack was not received\n");
 229         return false;
 230 }
 231
 232 /*
 233  * put the start of a message onto the bus
 234  */
 235 static void s3c24xx_i2c_message_start(struct s3c24xx_i2c *i2c,
 236                                       struct i2c_msg *msg)
 237 {
 238         unsigned int addr = (msg->addr & 0x7f) << 1;
 239         unsigned long stat;
 240         unsigned long iiccon;
 241
 242         stat = 0;
 243         stat |=  S3C2410_IICSTAT_TXRXEN;
 244
 245         if (msg->flags & I2C_M_RD) {
 246                 stat |= S3C2410_IICSTAT_MASTER_RX;
 247                 addr |= 1;
 248         } else
 249                 stat |= S3C2410_IICSTAT_MASTER_TX;
 250
 251         if (msg->flags & I2C_M_REV_DIR_ADDR)
 252                 addr ^= 1;
 253
 254         /* todo - check for whether ack wanted or not */
 255         s3c24xx_i2c_enable_ack(i2c);
 256
 257         iiccon = readl(i2c->regs + S3C2410_IICCON);
 258         writel(stat, i2c->regs + S3C2410_IICSTAT);
 259
 260         dev_dbg(i2c->dev, "START: %08lx to IICSTAT, %02x to DS\n", stat, addr);
 261         writeb(addr, i2c->regs + S3C2410_IICDS);
 262
 263         /*
 264          * delay here to ensure the data byte has gotten onto the bus
 265          * before the transaction is started
 266          */
 267         ndelay(i2c->tx_setup);
 268
 269         dev_dbg(i2c->dev, "iiccon, %08lx\n", iiccon);
 270         writel(iiccon, i2c->regs + S3C2410_IICCON);
 271
 272         stat |= S3C2410_IICSTAT_START;
 273         writel(stat, i2c->regs + S3C2410_IICSTAT);
 274
 275         if (i2c->quirks & QUIRK_POLL) {
 276                 while ((i2c->msg_num != 0) && is_ack(i2c)) {
 277                         i2c_s3c_irq_nextbyte(i2c, stat);
 278                         stat = readl(i2c->regs + S3C2410_IICSTAT);
 279
 280                         if (stat & S3C2410_IICSTAT_ARBITR)
 281                                 dev_err(i2c->dev, "deal with arbitration loss\n");
 282                 }
 283         }
 284 }
 285
 286 static inline void s3c24xx_i2c_stop(struct s3c24xx_i2c *i2c, int ret)
 287 {
 288         unsigned long iicstat = readl(i2c->regs + S3C2410_IICSTAT);
 289
 290         dev_dbg(i2c->dev, "STOP\n");
 291
 292         /*
 293          * The datasheet says that the STOP sequence should be:
 294          *  1) I2CSTAT.5 = 0    - Clear BUSY (or 'generate STOP')
 295          *  2) I2CCON.4 = 0     - Clear IRQPEND
 296          *  3) Wait until the stop condition takes effect.
 297          *  4*) I2CSTAT.4 = 0   - Clear TXRXEN
 298          *
 299          * Where, step "4*" is only for buses with the "HDMIPHY" quirk.
 300          *
 301          * However, after much experimentation, it appears that:
 302          * a) normal buses automatically clear BUSY and transition from
 303          *    Master->Slave when they complete generating a STOP condition.
 304          *    Therefore, step (3) can be done in doxfer() by polling I2CCON.4
 305          *    after starting the STOP generation here.
 306          * b) HDMIPHY bus does neither, so there is no way to do step 3.
 307          *    There is no indication when this bus has finished generating
 308          *    STOP.
 309          *
 310          * In fact, we have found that as soon as the IRQPEND bit is cleared in
 311          * step 2, the HDMIPHY bus generates the STOP condition, and then
 312          * immediately starts transferring another data byte, even though the
 313          * bus is supposedly stopped.  This is presumably because the bus is
 314          * still in "Master" mode, and its BUSY bit is still set.
 315          *
 316          * To avoid these extra post-STOP transactions on HDMI phy devices, we
 317          * just disable Serial Output on the bus (I2CSTAT.4 = 0) directly,
 318          * instead of first generating a proper STOP condition.  This should
 319          * float SDA & SCK terminating the transfer.  Subsequent transfers
 320          *  start with a proper START condition, and proceed normally.
 321          *
 322          * The HDMIPHY bus is an internal bus that always has exactly two
 323          * devices, the host as Master and the HDMIPHY device as the slave.
 324          * Skipping the STOP condition has been tested on this bus and works.
 325          */
 326         if (i2c->quirks & QUIRK_HDMIPHY) {
 327                 /* Stop driving the I2C pins */
 328                 iicstat &= ~S3C2410_IICSTAT_TXRXEN;
 329         } else {
 330                 /* stop the transfer */
 331                 iicstat &= ~S3C2410_IICSTAT_START;
 332         }
 333         writel(iicstat, i2c->regs + S3C2410_IICSTAT);
 334
 335         i2c->state = STATE_STOP;
 336
 337         s3c24xx_i2c_master_complete(i2c, ret);
 338         s3c24xx_i2c_disable_irq(i2c);
 339 }
 340
 341 /*
 342  * helper functions to determine the current state in the set of
 343  * messages we are sending
 344  */
 345
 346 /*
 347  * returns TRUE if the current message is the last in the set
 348  */
 349 static inline int is_lastmsg(struct s3c24xx_i2c *i2c)
 350 {
 351         return i2c->msg_idx >= (i2c->msg_num - 1);
 352 }
 353
 354 /*
 355  * returns TRUE if we this is the last byte in the current message
 356  */
 357 static inline int is_msglast(struct s3c24xx_i2c *i2c)
 358 {
 359         /*
 360          * msg->len is always 1 for the first byte of smbus block read.
 361          * Actual length will be read from slave. More bytes will be
 362          * read according to the length then.
 363          */
 364         if (i2c->msg->flags & I2C_M_RECV_LEN && i2c->msg->len == 1)
 365                 return 0;
 366
 367         return i2c->msg_ptr == i2c->msg->len-1;
 368 }
 369
 370 /*
 371  * returns TRUE if we reached the end of the current message
 372  */
 373 static inline int is_msgend(struct s3c24xx_i2c *i2c)
 374 {
 375         return i2c->msg_ptr >= i2c->msg->len;
 376 }
 377
 378 /*
 379  * process an interrupt and work out what to do
 380  */
 381 static int i2c_s3c_irq_nextbyte(struct s3c24xx_i2c *i2c, unsigned long iicstat)
 382 {
 383         unsigned long tmp;
 384         unsigned char byte;
 385         int ret = 0;
 386
 387         switch (i2c->state) {
 388
 389         case STATE_IDLE:
 390                 dev_err(i2c->dev, "%s: called in STATE_IDLE\n", __func__);
 391                 goto out;
 392
 393         case STATE_STOP:
 394                 dev_err(i2c->dev, "%s: called in STATE_STOP\n", __func__);
 395                 s3c24xx_i2c_disable_irq(i2c);
 396                 goto out_ack;
 397
 398         case STATE_START:
 399                 /*
 400                  * last thing we did was send a start condition on the
 401                  * bus, or started a new i2c message
 402                  */
 403                 if (iicstat & S3C2410_IICSTAT_LASTBIT &&
 404                     !(i2c->msg->flags & I2C_M_IGNORE_NAK)) {
 405                         /* ack was not received... */
 406                         dev_dbg(i2c->dev, "ack was not received\n");
 407                         s3c24xx_i2c_stop(i2c, -ENXIO);
 408                         goto out_ack;
 409                 }
 410
 411                 if (i2c->msg->flags & I2C_M_RD)
 412                         i2c->state = STATE_READ;
 413                 else
 414                         i2c->state = STATE_WRITE;
 415
 416                 /*
 417                  * Terminate the transfer if there is nothing to do
 418                  * as this is used by the i2c probe to find devices.
 419                  */
 420                 if (is_lastmsg(i2c) && i2c->msg->len == 0) {
 421                         s3c24xx_i2c_stop(i2c, 0);
 422                         goto out_ack;
 423                 }
 424
 425                 if (i2c->state == STATE_READ)
 426                         goto prepare_read;
 427
 428                 /*
 429                  * fall through to the write state, as we will need to
 430                  * send a byte as well
 431                  */
 432                 fallthrough;
 433         case STATE_WRITE:
 434                 /*
 435                  * we are writing data to the device... check for the
 436                  * end of the message, and if so, work out what to do
 437                  */
 438                 if (!(i2c->msg->flags & I2C_M_IGNORE_NAK)) {
 439                         if (iicstat & S3C2410_IICSTAT_LASTBIT) {
 440                                 dev_dbg(i2c->dev, "WRITE: No Ack\n");
 441
 442                                 s3c24xx_i2c_stop(i2c, -ECONNREFUSED);
 443                                 goto out_ack;
 444                         }
 445                 }
 446
 447  retry_write:
 448
 449                 if (!is_msgend(i2c)) {
 450                         byte = i2c->msg->buf[i2c->msg_ptr++];
 451                         writeb(byte, i2c->regs + S3C2410_IICDS);
 452
 453                         /*
 454                          * delay after writing the byte to allow the
 455                          * data setup time on the bus, as writing the
 456                          * data to the register causes the first bit
 457                          * to appear on SDA, and SCL will change as
 458                          * soon as the interrupt is acknowledged
 459                          */
 460                         ndelay(i2c->tx_setup);
 461
 462                 } else if (!is_lastmsg(i2c)) {
 463                         /* we need to go to the next i2c message */
 464
 465                         dev_dbg(i2c->dev, "WRITE: Next Message\n");
 466
 467                         i2c->msg_ptr = 0;
 468                         i2c->msg_idx++;
 469                         i2c->msg++;
 470
 471                         /* check to see if we need to do another message */
 472                         if (i2c->msg->flags & I2C_M_NOSTART) {
 473
 474                                 if (i2c->msg->flags & I2C_M_RD) {
 475                                         /*
 476                                          * cannot do this, the controller
 477                                          * forces us to send a new START
 478                                          * when we change direction
 479                                          */
 480                                         dev_dbg(i2c->dev,
 481                                                 "missing START before write->read\n");
 482                                         s3c24xx_i2c_stop(i2c, -EINVAL);
 483                                         break;
 484                                 }
 485
 486                                 goto retry_write;
 487                         } else {
 488                                 /* send the new start */
 489                                 s3c24xx_i2c_message_start(i2c, i2c->msg);
 490                                 i2c->state = STATE_START;
 491                         }
 492
 493                 } else {
 494                         /* send stop */
 495                         s3c24xx_i2c_stop(i2c, 0);
 496                 }
 497                 break;
 498
 499         case STATE_READ:
 500                 /*
 501                  * we have a byte of data in the data register, do
 502                  * something with it, and then work out whether we are
 503                  * going to do any more read/write
 504                  */
 505                 byte = readb(i2c->regs + S3C2410_IICDS);
 506                 i2c->msg->buf[i2c->msg_ptr++] = byte;
 507
 508                 /* Add actual length to read for smbus block read */
 509                 if (i2c->msg->flags & I2C_M_RECV_LEN && i2c->msg->len == 1)
 510                         i2c->msg->len += byte;
 511  prepare_read:
 512                 if (is_msglast(i2c)) {
 513                         /* last byte of buffer */
 514
 515                         if (is_lastmsg(i2c))
 516                                 s3c24xx_i2c_disable_ack(i2c);
 517
 518                 } else if (is_msgend(i2c)) {
 519                         /*
 520                          * ok, we've read the entire buffer, see if there
 521                          * is anything else we need to do
 522                          */
 523                         if (is_lastmsg(i2c)) {
 524                                 /* last message, send stop and complete */
 525                                 dev_dbg(i2c->dev, "READ: Send Stop\n");
 526
 527                                 s3c24xx_i2c_stop(i2c, 0);
 528                         } else {
 529                                 /* go to the next transfer */
 530                                 dev_dbg(i2c->dev, "READ: Next Transfer\n");
 531
 532                                 i2c->msg_ptr = 0;
 533                                 i2c->msg_idx++;
 534                                 i2c->msg++;
 535                         }
 536                 }
 537
 538                 break;
 539         }
 540
 541         /* acknowlegde the IRQ and get back on with the work */
 542
 543  out_ack:
 544         tmp = readl(i2c->regs + S3C2410_IICCON);
 545         tmp &= ~S3C2410_IICCON_IRQPEND;
 546         writel(tmp, i2c->regs + S3C2410_IICCON);
 547  out:
 548         return ret;
 549 }
 550
 551 /*
 552  * top level IRQ servicing routine
 553  */
 554 static irqreturn_t s3c24xx_i2c_irq(int irqno, void *dev_id)
 555 {
 556         struct s3c24xx_i2c *i2c = dev_id;
 557         unsigned long status;
 558         unsigned long tmp;
 559
 560         status = readl(i2c->regs + S3C2410_IICSTAT);
 561
 562         if (status & S3C2410_IICSTAT_ARBITR) {
 563                 /* deal with arbitration loss */
 564                 dev_err(i2c->dev, "deal with arbitration loss\n");
 565         }
 566
 567         if (i2c->state == STATE_IDLE) {
 568                 dev_dbg(i2c->dev, "IRQ: error i2c->state == IDLE\n");
 569
 570                 tmp = readl(i2c->regs + S3C2410_IICCON);
 571                 tmp &= ~S3C2410_IICCON_IRQPEND;
 572                 writel(tmp, i2c->regs +  S3C2410_IICCON);
 573                 goto out;
 574         }
 575
 576         /*
 577          * pretty much this leaves us with the fact that we've
 578          * transmitted or received whatever byte we last sent
 579          */
 580         i2c_s3c_irq_nextbyte(i2c, status);
 581
 582  out:
 583         return IRQ_HANDLED;
 584 }
 585
 586 /*
 587  * Disable the bus so that we won't get any interrupts from now on, or try
 588  * to drive any lines. This is the default state when we don't have
 589  * anything to send/receive.
 590  *
 591  * If there is an event on the bus, or we have a pre-existing event at
 592  * kernel boot time, we may not notice the event and the I2C controller
 593  * will lock the bus with the I2C clock line low indefinitely.
 594  */
 595 static inline void s3c24xx_i2c_disable_bus(struct s3c24xx_i2c *i2c)
 596 {
 597         unsigned long tmp;
 598
 599         /* Stop driving the I2C pins */
 600         tmp = readl(i2c->regs + S3C2410_IICSTAT);
 601         tmp &= ~S3C2410_IICSTAT_TXRXEN;
 602         writel(tmp, i2c->regs + S3C2410_IICSTAT);
 603
 604         /* We don't expect any interrupts now, and don't want send acks */
 605         tmp = readl(i2c->regs + S3C2410_IICCON);
 606         tmp &= ~(S3C2410_IICCON_IRQEN | S3C2410_IICCON_IRQPEND |
 607                 S3C2410_IICCON_ACKEN);
 608         writel(tmp, i2c->regs + S3C2410_IICCON);
 609 }
 610
 611
 612 /*
 613  * get the i2c bus for a master transaction
 614  */
 615 static int s3c24xx_i2c_set_master(struct s3c24xx_i2c *i2c)
 616 {
 617         unsigned long iicstat;
 618         int timeout = 400;
 619
 620         while (timeout-- > 0) {
 621                 iicstat = readl(i2c->regs + S3C2410_IICSTAT);
 622
 623                 if (!(iicstat & S3C2410_IICSTAT_BUSBUSY))
 624                         return 0;
 625
 626                 msleep(1);
 627         }
 628
 629         return -ETIMEDOUT;
 630 }
 631
 632 /*
 633  * wait for the i2c bus to become idle.
 634  */
 635 static void s3c24xx_i2c_wait_idle(struct s3c24xx_i2c *i2c)
 636 {
 637         unsigned long iicstat;
 638         ktime_t start, now;
 639         unsigned long delay;
 640         int spins;
 641
 642         /* ensure the stop has been through the bus */
 643
 644         dev_dbg(i2c->dev, "waiting for bus idle\n");
 645
 646         start = now = ktime_get();
 647
 648         /*
 649          * Most of the time, the bus is already idle within a few usec of the
 650          * end of a transaction.  However, really slow i2c devices can stretch
 651          * the clock, delaying STOP generation.
 652          *
 653          * On slower SoCs this typically happens within a very small number of
 654          * instructions so busy wait briefly to avoid scheduling overhead.
 655          */
 656         spins = 3;
 657         iicstat = readl(i2c->regs + S3C2410_IICSTAT);
 658         while ((iicstat & S3C2410_IICSTAT_START) && --spins) {
 659                 cpu_relax();
 660                 iicstat = readl(i2c->regs + S3C2410_IICSTAT);
 661         }
 662
 663         /*
 664          * If we do get an appreciable delay as a compromise between idle
 665          * detection latency for the normal, fast case, and system load in the
 666          * slow device case, use an exponential back off in the polling loop,
 667          * up to 1/10th of the total timeout, then continue to poll at a
 668          * constant rate up to the timeout.
 669          */
 670         delay = 1;
 671         while ((iicstat & S3C2410_IICSTAT_START) &&
 672                ktime_us_delta(now, start) < S3C2410_IDLE_TIMEOUT) {
 673                 usleep_range(delay, 2 * delay);
 674                 if (delay < S3C2410_IDLE_TIMEOUT / 10)
 675                         delay <<= 1;
 676                 now = ktime_get();
 677                 iicstat = readl(i2c->regs + S3C2410_IICSTAT);
 678         }
 679
 680         if (iicstat & S3C2410_IICSTAT_START)
 681                 dev_warn(i2c->dev, "timeout waiting for bus idle\n");
 682 }
 683
 684 /*
 685  * this starts an i2c transfer
 686  */
 687 static int s3c24xx_i2c_doxfer(struct s3c24xx_i2c *i2c,
 688                               struct i2c_msg *msgs, int num)
 689 {
 690         unsigned long timeout;
 691         int ret;
 692
 693         ret = s3c24xx_i2c_set_master(i2c);
 694         if (ret != 0) {
 695                 dev_err(i2c->dev, "cannot get bus (error %d)\n", ret);
 696                 ret = -EAGAIN;
 697                 goto out;
 698         }
 699
 700         i2c->msg     = msgs;
 701         i2c->msg_num = num;
 702         i2c->msg_ptr = 0;
 703         i2c->msg_idx = 0;
 704         i2c->state   = STATE_START;
 705
 706         s3c24xx_i2c_enable_irq(i2c);
 707         s3c24xx_i2c_message_start(i2c, msgs);
 708
 709         if (i2c->quirks & QUIRK_POLL) {
 710                 ret = i2c->msg_idx;
 711
 712                 if (ret != num)
 713                         dev_dbg(i2c->dev, "incomplete xfer (%d)\n", ret);
 714
 715                 goto out;
 716         }
 717
 718         timeout = wait_event_timeout(i2c->wait, i2c->msg_num == 0, HZ * 5);
 719
 720         ret = i2c->msg_idx;
 721
 722         /*
 723          * Having these next two as dev_err() makes life very
 724          * noisy when doing an i2cdetect
 725          */
 726         if (timeout == 0)
 727                 dev_dbg(i2c->dev, "timeout\n");
 728         else if (ret != num)
 729                 dev_dbg(i2c->dev, "incomplete xfer (%d)\n", ret);
 730
 731         /* For QUIRK_HDMIPHY, bus is already disabled */
 732         if (i2c->quirks & QUIRK_HDMIPHY)
 733                 goto out;
 734
 735         s3c24xx_i2c_wait_idle(i2c);
 736
 737         s3c24xx_i2c_disable_bus(i2c);
 738
 739  out:
 740         i2c->state = STATE_IDLE;
 741
 742         return ret;
 743 }
 744
 745 /*
 746  * first port of call from the i2c bus code when an message needs
 747  * transferring across the i2c bus.
 748  */
 749 static int s3c24xx_i2c_xfer(struct i2c_adapter *adap,
 750                         struct i2c_msg *msgs, int num)
 751 {
 752         struct s3c24xx_i2c *i2c = (struct s3c24xx_i2c *)adap->algo_data;
 753         int retry;
 754         int ret;
 755
 756         ret = clk_enable(i2c->clk);
 757         if (ret)
 758                 return ret;
 759
 760         for (retry = 0; retry < adap->retries; retry++) {
 761
 762                 ret = s3c24xx_i2c_doxfer(i2c, msgs, num);
 763
 764                 if (ret != -EAGAIN) {
 765                         clk_disable(i2c->clk);
 766                         return ret;
 767                 }
 768
 769                 dev_dbg(i2c->dev, "Retrying transmission (%d)\n", retry);
 770
 771                 udelay(100);
 772         }
 773
 774         clk_disable(i2c->clk);
 775         return -EREMOTEIO;
 776 }
 777
 778 /* declare our i2c functionality */
 779 static u32 s3c24xx_i2c_func(struct i2c_adapter *adap)
 780 {
 781         return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL_ALL | I2C_FUNC_NOSTART |
 782                 I2C_FUNC_PROTOCOL_MANGLING;
 783 }
 784
 785 /* i2c bus registration info */
 786 static const struct i2c_algorithm s3c24xx_i2c_algorithm = {
 787         .master_xfer            = s3c24xx_i2c_xfer,
 788         .functionality          = s3c24xx_i2c_func,
 789 };
 790
 791 /*
 792  * return the divisor settings for a given frequency
 793  */
 794 static int s3c24xx_i2c_calcdivisor(unsigned long clkin, unsigned int wanted,
 795                                    unsigned int *div1, unsigned int *divs)
 796 {
 797         unsigned int calc_divs = clkin / wanted;
 798         unsigned int calc_div1;
 799
 800         if (calc_divs > (16*16))
 801                 calc_div1 = 512;
 802         else
 803                 calc_div1 = 16;
 804
 805         calc_divs += calc_div1-1;
 806         calc_divs /= calc_div1;
 807
 808         if (calc_divs == 0)
 809                 calc_divs = 1;
 810         if (calc_divs > 17)
 811                 calc_divs = 17;
 812
 813         *divs = calc_divs;
 814         *div1 = calc_div1;
 815
 816         return clkin / (calc_divs * calc_div1);
 817 }
 818
 819 /*
 820  * work out a divisor for the user requested frequency setting,
 821  * either by the requested frequency, or scanning the acceptable
 822  * range of frequencies until something is found
 823  */
 824 static int s3c24xx_i2c_clockrate(struct s3c24xx_i2c *i2c, unsigned int *got)
 825 {
 826         struct s3c2410_platform_i2c *pdata = i2c->pdata;
 827         unsigned long clkin = clk_get_rate(i2c->clk);
 828         unsigned int divs, div1;
 829         unsigned long target_frequency;
 830         u32 iiccon;
 831         int freq;
 832
 833         i2c->clkrate = clkin;
 834         clkin /= 1000;  /* clkin now in KHz */
 835
 836         dev_dbg(i2c->dev, "pdata desired frequency %lu\n", pdata->frequency);
 837
 838         target_frequency = pdata->frequency ?: I2C_MAX_STANDARD_MODE_FREQ;
 839
 840         target_frequency /= 1000; /* Target frequency now in KHz */
 841
 842         freq = s3c24xx_i2c_calcdivisor(clkin, target_frequency, &div1, &divs);
 843
 844         if (freq > target_frequency) {
 845                 dev_err(i2c->dev,
 846                         "Unable to achieve desired frequency %luKHz."   \
 847                         " Lowest achievable %dKHz\n", target_frequency, freq);
 848                 return -EINVAL;
 849         }
 850
 851         *got = freq;
 852
 853         iiccon = readl(i2c->regs + S3C2410_IICCON);
 854         iiccon &= ~(S3C2410_IICCON_SCALEMASK | S3C2410_IICCON_TXDIV_512);
 855         iiccon |= (divs-1);
 856
 857         if (div1 == 512)
 858                 iiccon |= S3C2410_IICCON_TXDIV_512;
 859
 860         if (i2c->quirks & QUIRK_POLL)
 861                 iiccon |= S3C2410_IICCON_SCALE(2);
 862
 863         writel(iiccon, i2c->regs + S3C2410_IICCON);
 864
 865         if (i2c->quirks & QUIRK_S3C2440) {
 866                 unsigned long sda_delay;
 867
 868                 if (pdata->sda_delay) {
 869                         sda_delay = clkin * pdata->sda_delay;
 870                         sda_delay = DIV_ROUND_UP(sda_delay, 1000000);
 871                         sda_delay = DIV_ROUND_UP(sda_delay, 5);
 872                         if (sda_delay > 3)
 873                                 sda_delay = 3;
 874                         sda_delay |= S3C2410_IICLC_FILTER_ON;
 875                 } else
 876                         sda_delay = 0;
 877
 878                 dev_dbg(i2c->dev, "IICLC=%08lx\n", sda_delay);
 879                 writel(sda_delay, i2c->regs + S3C2440_IICLC);
 880         }
 881
 882         return 0;
 883 }
 884
 885 #ifdef CONFIG_OF
 886 static int s3c24xx_i2c_parse_dt_gpio(struct s3c24xx_i2c *i2c)
 887 {
 888         int i;
 889
 890         if (i2c->quirks & QUIRK_NO_GPIO)
 891                 return 0;
 892
 893         for (i = 0; i < 2; i++) {
 894                 i2c->gpios[i] = devm_gpiod_get_index(i2c->dev, NULL,
 895                                                      i, GPIOD_ASIS);
 896                 if (IS_ERR(i2c->gpios[i])) {
 897                         dev_err(i2c->dev, "i2c gpio invalid at index %d\n", i);
 898                         return -EINVAL;
 899                 }
 900         }
 901         return 0;
 902 }
 903
 904 #else
 905 static int s3c24xx_i2c_parse_dt_gpio(struct s3c24xx_i2c *i2c)
 906 {
 907         return 0;
 908 }
 909 #endif
 910
 911 /*
 912  * initialise the controller, set the IO lines and frequency
 913  */
 914 static int s3c24xx_i2c_init(struct s3c24xx_i2c *i2c)
 915 {
 916         struct s3c2410_platform_i2c *pdata;
 917         unsigned int freq;
 918
 919         /* get the plafrom data */
 920
 921         pdata = i2c->pdata;
 922
 923         /* write slave address */
 924
 925         writeb(pdata->slave_addr, i2c->regs + S3C2410_IICADD);
 926
 927         dev_info(i2c->dev, "slave address 0x%02x\n", pdata->slave_addr);
 928
 929         writel(0, i2c->regs + S3C2410_IICCON);
 930         writel(0, i2c->regs + S3C2410_IICSTAT);
 931
 932         /* we need to work out the divisors for the clock... */
 933
 934         if (s3c24xx_i2c_clockrate(i2c, &freq) != 0) {
 935                 dev_err(i2c->dev, "cannot meet bus frequency required\n");
 936                 return -EINVAL;
 937         }
 938
 939         /* todo - check that the i2c lines aren't being dragged anywhere */
 940
 941         dev_info(i2c->dev, "bus frequency set to %d KHz\n", freq);
 942         dev_dbg(i2c->dev, "S3C2410_IICCON=0x%02x\n",
 943                 readl(i2c->regs + S3C2410_IICCON));
 944
 945         return 0;
 946 }
 947
 948 #ifdef CONFIG_OF
 949 /*
 950  * Parse the device tree node and retreive the platform data.
 951  */
 952 static void
 953 s3c24xx_i2c_parse_dt(struct device_node *np, struct s3c24xx_i2c *i2c)
 954 {
 955         struct s3c2410_platform_i2c *pdata = i2c->pdata;
 956         int id;
 957
 958         if (!np)
 959                 return;
 960
 961         pdata->bus_num = -1; /* i2c bus number is dynamically assigned */
 962         of_property_read_u32(np, "samsung,i2c-sda-delay", &pdata->sda_delay);
 963         of_property_read_u32(np, "samsung,i2c-slave-addr", &pdata->slave_addr);
 964         of_property_read_u32(np, "samsung,i2c-max-bus-freq",
 965                                 (u32 *)&pdata->frequency);
 966         /*
 967          * Exynos5's legacy i2c controller and new high speed i2c
 968          * controller have muxed interrupt sources. By default the
 969          * interrupts for 4-channel HS-I2C controller are enabled.
 970          * If nodes for first four channels of legacy i2c controller
 971          * are available then re-configure the interrupts via the
 972          * system register.
 973          */
 974         id = of_alias_get_id(np, "i2c");
 975         i2c->sysreg = syscon_regmap_lookup_by_phandle(np,
 976                         "samsung,sysreg-phandle");
 977         if (IS_ERR(i2c->sysreg))
 978                 return;
 979
 980         regmap_update_bits(i2c->sysreg, EXYNOS5_SYS_I2C_CFG, BIT(id), 0);
 981 }
 982 #else
 983 static void
 984 s3c24xx_i2c_parse_dt(struct device_node *np, struct s3c24xx_i2c *i2c) { }
 985 #endif
 986
 987 static int s3c24xx_i2c_probe(struct platform_device *pdev)
 988 {
 989         struct s3c24xx_i2c *i2c;
 990         struct s3c2410_platform_i2c *pdata = NULL;
 991         struct resource *res;
 992         int ret;
 993
 994         if (!pdev->dev.of_node) {
 995                 pdata = dev_get_platdata(&pdev->dev);
 996                 if (!pdata) {
 997                         dev_err(&pdev->dev, "no platform data\n");
 998                         return -EINVAL;
 999                 }
1000         }
1001
1002         i2c = devm_kzalloc(&pdev->dev, sizeof(struct s3c24xx_i2c), GFP_KERNEL);
1003         if (!i2c)
1004                 return -ENOMEM;
1005
1006         i2c->pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
1007         if (!i2c->pdata)
1008                 return -ENOMEM;
1009
1010         i2c->quirks = s3c24xx_get_device_quirks(pdev);
1011         i2c->sysreg = ERR_PTR(-ENOENT);
1012         if (pdata)
1013                 memcpy(i2c->pdata, pdata, sizeof(*pdata));
1014         else
1015                 s3c24xx_i2c_parse_dt(pdev->dev.of_node, i2c);
1016
1017         strscpy(i2c->adap.name, "s3c2410-i2c", sizeof(i2c->adap.name));
1018         i2c->adap.owner = THIS_MODULE;
1019         i2c->adap.algo = &s3c24xx_i2c_algorithm;
1020         i2c->adap.retries = 2;
1021         i2c->adap.class = I2C_CLASS_DEPRECATED;
1022         i2c->tx_setup = 50;
1023
1024         init_waitqueue_head(&i2c->wait);
1025
1026         /* find the clock and enable it */
1027         i2c->dev = &pdev->dev;
1028         i2c->clk = devm_clk_get(&pdev->dev, "i2c");
1029         if (IS_ERR(i2c->clk)) {
1030                 dev_err(&pdev->dev, "cannot get clock\n");
1031                 return -ENOENT;
1032         }
1033
1034         dev_dbg(&pdev->dev, "clock source %p\n", i2c->clk);
1035
1036         /* map the registers */
1037         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1038         i2c->regs = devm_ioremap_resource(&pdev->dev, res);
1039
1040         if (IS_ERR(i2c->regs))
1041                 return PTR_ERR(i2c->regs);
1042
1043         dev_dbg(&pdev->dev, "registers %p (%p)\n",
1044                 i2c->regs, res);
1045
1046         /* setup info block for the i2c core */
1047         i2c->adap.algo_data = i2c;
1048         i2c->adap.dev.parent = &pdev->dev;
1049         i2c->pctrl = devm_pinctrl_get_select_default(i2c->dev);
1050
1051         /* inititalise the i2c gpio lines */
1052         if (i2c->pdata->cfg_gpio)
1053                 i2c->pdata->cfg_gpio(to_platform_device(i2c->dev));
1054         else if (IS_ERR(i2c->pctrl) && s3c24xx_i2c_parse_dt_gpio(i2c))
1055                 return -EINVAL;
1056
1057         /* initialise the i2c controller */
1058         ret = clk_prepare_enable(i2c->clk);
1059         if (ret) {
1060                 dev_err(&pdev->dev, "I2C clock enable failed\n");
1061                 return ret;
1062         }
1063
1064         ret = s3c24xx_i2c_init(i2c);
1065         clk_disable(i2c->clk);
1066         if (ret != 0) {
1067                 dev_err(&pdev->dev, "I2C controller init failed\n");
1068                 clk_unprepare(i2c->clk);
1069                 return ret;
1070         }
1071
1072         /*
1073          * find the IRQ for this unit (note, this relies on the init call to
1074          * ensure no current IRQs pending
1075          */
1076         if (!(i2c->quirks & QUIRK_POLL)) {
1077                 i2c->irq = ret = platform_get_irq(pdev, 0);
1078                 if (ret < 0) {
1079                         dev_err(&pdev->dev, "cannot find IRQ\n");
1080                         clk_unprepare(i2c->clk);
1081                         return ret;
1082                 }
1083
1084                 ret = devm_request_irq(&pdev->dev, i2c->irq, s3c24xx_i2c_irq,
1085                                        0, dev_name(&pdev->dev), i2c);
1086                 if (ret != 0) {
1087                         dev_err(&pdev->dev, "cannot claim IRQ %d\n", i2c->irq);
1088                         clk_unprepare(i2c->clk);
1089                         return ret;
1090                 }
1091         }
1092
1093         /*
1094          * Note, previous versions of the driver used i2c_add_adapter()
1095          * to add the bus at any number. We now pass the bus number via
1096          * the platform data, so if unset it will now default to always
1097          * being bus 0.
1098          */
1099         i2c->adap.nr = i2c->pdata->bus_num;
1100         i2c->adap.dev.of_node = pdev->dev.of_node;
1101
1102         platform_set_drvdata(pdev, i2c);
1103
1104         pm_runtime_enable(&pdev->dev);
1105
1106         ret = i2c_add_numbered_adapter(&i2c->adap);
1107         if (ret < 0) {
1108                 pm_runtime_disable(&pdev->dev);
1109                 clk_unprepare(i2c->clk);
1110                 return ret;
1111         }
1112
1113         dev_info(&pdev->dev, "%s: S3C I2C adapter\n", dev_name(&i2c->adap.dev));
1114         return 0;
1115 }
1116
1117 static void s3c24xx_i2c_remove(struct platform_device *pdev)
1118 {
1119         struct s3c24xx_i2c *i2c = platform_get_drvdata(pdev);
1120
1121         clk_unprepare(i2c->clk);
1122
1123         pm_runtime_disable(&pdev->dev);
1124
1125         i2c_del_adapter(&i2c->adap);
1126 }
1127
1128 #ifdef CONFIG_PM_SLEEP
1129 static int s3c24xx_i2c_suspend_noirq(struct device *dev)
1130 {
1131         struct s3c24xx_i2c *i2c = dev_get_drvdata(dev);
1132
1133         i2c_mark_adapter_suspended(&i2c->adap);
1134
1135         if (!IS_ERR(i2c->sysreg))
1136                 regmap_read(i2c->sysreg, EXYNOS5_SYS_I2C_CFG, &i2c->sys_i2c_cfg);
1137
1138         return 0;
1139 }
1140
1141 static int s3c24xx_i2c_resume_noirq(struct device *dev)
1142 {
1143         struct s3c24xx_i2c *i2c = dev_get_drvdata(dev);
1144         int ret;
1145
1146         if (!IS_ERR(i2c->sysreg))
1147                 regmap_write(i2c->sysreg, EXYNOS5_SYS_I2C_CFG, i2c->sys_i2c_cfg);
1148
1149         ret = clk_enable(i2c->clk);
1150         if (ret)
1151                 return ret;
1152         s3c24xx_i2c_init(i2c);
1153         clk_disable(i2c->clk);
1154         i2c_mark_adapter_resumed(&i2c->adap);
1155
1156         return 0;
1157 }
1158 #endif
1159
1160 #ifdef CONFIG_PM
1161 static const struct dev_pm_ops s3c24xx_i2c_dev_pm_ops = {
1162         SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(s3c24xx_i2c_suspend_noirq,
1163                                       s3c24xx_i2c_resume_noirq)
1164 };
1165
1166 #define S3C24XX_DEV_PM_OPS (&s3c24xx_i2c_dev_pm_ops)
1167 #else
1168 #define S3C24XX_DEV_PM_OPS NULL
1169 #endif
1170
1171 static struct platform_driver s3c24xx_i2c_driver = {
1172         .probe          = s3c24xx_i2c_probe,
1173         .remove_new     = s3c24xx_i2c_remove,
1174         .id_table       = s3c24xx_driver_ids,
1175         .driver         = {
1176                 .name   = "s3c-i2c",
1177                 .pm     = S3C24XX_DEV_PM_OPS,
1178                 .of_match_table = of_match_ptr(s3c24xx_i2c_match),
1179         },
1180 };
1181
1182 static int __init i2c_adap_s3c_init(void)
1183 {
1184         return platform_driver_register(&s3c24xx_i2c_driver);
1185 }
1186 subsys_initcall(i2c_adap_s3c_init);
1187
1188 static void __exit i2c_adap_s3c_exit(void)
1189 {
1190         platform_driver_unregister(&s3c24xx_i2c_driver);
1191 }
1192 module_exit(i2c_adap_s3c_exit);
1193
1194 MODULE_DESCRIPTION("S3C24XX I2C Bus driver");
1195 MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>");
1196 MODULE_LICENSE("GPL");