1 /* linux/drivers/i2c/busses/i2c-s3c2410.c 2 * 3 * Copyright (C) 2004,2005,2009 Simtec Electronics 4 * Ben Dooks <ben@simtec.co.uk> 5 * 6 * S3C2410 I2C Controller 7 * 8 * This program is free software; you can redistribute it and/or modify 9 * it under the terms of the GNU General Public License as published by 10 * the Free Software Foundation; either version 2 of the License, or 11 * (at your option) any later version. 12 * 13 * This program is distributed in the hope that it will be useful, 14 * but WITHOUT ANY WARRANTY; without even the implied warranty of 15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 16 * GNU General Public License for more details. 17 * 18 * You should have received a copy of the GNU General Public License 19 * along with this program; if not, write to the Free Software 20 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 21 */ 22 23 #include <linux/kernel.h> 24 #include <linux/module.h> 25 26 #include <linux/i2c.h> 27 #include <linux/i2c-id.h> 28 #include <linux/init.h> 29 #include <linux/time.h> 30 #include <linux/interrupt.h> 31 #include <linux/delay.h> 32 #include <linux/errno.h> 33 #include <linux/err.h> 34 #include <linux/platform_device.h> 35 #include <linux/clk.h> 36 #include <linux/cpufreq.h> 37 #include <linux/slab.h> 38 39 #include <asm/irq.h> 40 #include <asm/io.h> 41 42 #include <plat/regs-iic.h> 43 #include <plat/iic.h> 44 45 /* i2c controller state */ 46 47 enum s3c24xx_i2c_state { 48 STATE_IDLE, 49 STATE_START, 50 STATE_READ, 51 STATE_WRITE, 52 STATE_STOP 53 }; 54 55 enum s3c24xx_i2c_type { 56 TYPE_S3C2410, 57 TYPE_S3C2440, 58 }; 59 60 struct s3c24xx_i2c { 61 spinlock_t lock; 62 wait_queue_head_t wait; 63 unsigned int suspended:1; 64 65 struct i2c_msg *msg; 66 unsigned int msg_num; 67 unsigned int msg_idx; 68 unsigned int msg_ptr; 69 70 unsigned int tx_setup; 71 unsigned int irq; 72 73 enum s3c24xx_i2c_state state; 74 unsigned long clkrate; 75 76 void __iomem *regs; 77 struct clk *clk; 78 struct device *dev; 79 struct resource *ioarea; 80 struct i2c_adapter adap; 81 82 #ifdef CONFIG_CPU_FREQ 83 struct notifier_block freq_transition; 84 #endif 85 }; 86 87 /* default platform data removed, dev should always carry data. */ 88 89 /* s3c24xx_i2c_is2440() 90 * 91 * return true is this is an s3c2440 92 */ 93 94 static inline int s3c24xx_i2c_is2440(struct s3c24xx_i2c *i2c) 95 { 96 struct platform_device *pdev = to_platform_device(i2c->dev); 97 enum s3c24xx_i2c_type type; 98 99 type = platform_get_device_id(pdev)->driver_data; 100 return type == TYPE_S3C2440; 101 } 102 103 /* s3c24xx_i2c_master_complete 104 * 105 * complete the message and wake up the caller, using the given return code, 106 * or zero to mean ok. 107 */ 108 109 static inline void s3c24xx_i2c_master_complete(struct s3c24xx_i2c *i2c, int ret) 110 { 111 dev_dbg(i2c->dev, "master_complete %d\n", ret); 112 113 i2c->msg_ptr = 0; 114 i2c->msg = NULL; 115 i2c->msg_idx++; 116 i2c->msg_num = 0; 117 if (ret) 118 i2c->msg_idx = ret; 119 120 wake_up(&i2c->wait); 121 } 122 123 static inline void s3c24xx_i2c_disable_ack(struct s3c24xx_i2c *i2c) 124 { 125 unsigned long tmp; 126 127 tmp = readl(i2c->regs + S3C2410_IICCON); 128 writel(tmp & ~S3C2410_IICCON_ACKEN, i2c->regs + S3C2410_IICCON); 129 } 130 131 static inline void s3c24xx_i2c_enable_ack(struct s3c24xx_i2c *i2c) 132 { 133 unsigned long tmp; 134 135 tmp = readl(i2c->regs + S3C2410_IICCON); 136 writel(tmp | S3C2410_IICCON_ACKEN, i2c->regs + S3C2410_IICCON); 137 } 138 139 /* irq enable/disable functions */ 140 141 static inline void s3c24xx_i2c_disable_irq(struct s3c24xx_i2c *i2c) 142 { 143 unsigned long tmp; 144 145 tmp = readl(i2c->regs + S3C2410_IICCON); 146 writel(tmp & ~S3C2410_IICCON_IRQEN, i2c->regs + S3C2410_IICCON); 147 } 148 149 static inline void s3c24xx_i2c_enable_irq(struct s3c24xx_i2c *i2c) 150 { 151 unsigned long tmp; 152 153 tmp = readl(i2c->regs + S3C2410_IICCON); 154 writel(tmp | S3C2410_IICCON_IRQEN, i2c->regs + S3C2410_IICCON); 155 } 156 157 158 /* s3c24xx_i2c_message_start 159 * 160 * put the start of a message onto the bus 161 */ 162 163 static void s3c24xx_i2c_message_start(struct s3c24xx_i2c *i2c, 164 struct i2c_msg *msg) 165 { 166 unsigned int addr = (msg->addr & 0x7f) << 1; 167 unsigned long stat; 168 unsigned long iiccon; 169 170 stat = 0; 171 stat |= S3C2410_IICSTAT_TXRXEN; 172 173 if (msg->flags & I2C_M_RD) { 174 stat |= S3C2410_IICSTAT_MASTER_RX; 175 addr |= 1; 176 } else 177 stat |= S3C2410_IICSTAT_MASTER_TX; 178 179 if (msg->flags & I2C_M_REV_DIR_ADDR) 180 addr ^= 1; 181 182 /* todo - check for wether ack wanted or not */ 183 s3c24xx_i2c_enable_ack(i2c); 184 185 iiccon = readl(i2c->regs + S3C2410_IICCON); 186 writel(stat, i2c->regs + S3C2410_IICSTAT); 187 188 dev_dbg(i2c->dev, "START: %08lx to IICSTAT, %02x to DS\n", stat, addr); 189 writeb(addr, i2c->regs + S3C2410_IICDS); 190 191 /* delay here to ensure the data byte has gotten onto the bus 192 * before the transaction is started */ 193 194 ndelay(i2c->tx_setup); 195 196 dev_dbg(i2c->dev, "iiccon, %08lx\n", iiccon); 197 writel(iiccon, i2c->regs + S3C2410_IICCON); 198 199 stat |= S3C2410_IICSTAT_START; 200 writel(stat, i2c->regs + S3C2410_IICSTAT); 201 } 202 203 static inline void s3c24xx_i2c_stop(struct s3c24xx_i2c *i2c, int ret) 204 { 205 unsigned long iicstat = readl(i2c->regs + S3C2410_IICSTAT); 206 207 dev_dbg(i2c->dev, "STOP\n"); 208 209 /* stop the transfer */ 210 iicstat &= ~S3C2410_IICSTAT_START; 211 writel(iicstat, i2c->regs + S3C2410_IICSTAT); 212 213 i2c->state = STATE_STOP; 214 215 s3c24xx_i2c_master_complete(i2c, ret); 216 s3c24xx_i2c_disable_irq(i2c); 217 } 218 219 /* helper functions to determine the current state in the set of 220 * messages we are sending */ 221 222 /* is_lastmsg() 223 * 224 * returns TRUE if the current message is the last in the set 225 */ 226 227 static inline int is_lastmsg(struct s3c24xx_i2c *i2c) 228 { 229 return i2c->msg_idx >= (i2c->msg_num - 1); 230 } 231 232 /* is_msglast 233 * 234 * returns TRUE if we this is the last byte in the current message 235 */ 236 237 static inline int is_msglast(struct s3c24xx_i2c *i2c) 238 { 239 return i2c->msg_ptr == i2c->msg->len-1; 240 } 241 242 /* is_msgend 243 * 244 * returns TRUE if we reached the end of the current message 245 */ 246 247 static inline int is_msgend(struct s3c24xx_i2c *i2c) 248 { 249 return i2c->msg_ptr >= i2c->msg->len; 250 } 251 252 /* i2s_s3c_irq_nextbyte 253 * 254 * process an interrupt and work out what to do 255 */ 256 257 static int i2s_s3c_irq_nextbyte(struct s3c24xx_i2c *i2c, unsigned long iicstat) 258 { 259 unsigned long tmp; 260 unsigned char byte; 261 int ret = 0; 262 263 switch (i2c->state) { 264 265 case STATE_IDLE: 266 dev_err(i2c->dev, "%s: called in STATE_IDLE\n", __func__); 267 goto out; 268 break; 269 270 case STATE_STOP: 271 dev_err(i2c->dev, "%s: called in STATE_STOP\n", __func__); 272 s3c24xx_i2c_disable_irq(i2c); 273 goto out_ack; 274 275 case STATE_START: 276 /* last thing we did was send a start condition on the 277 * bus, or started a new i2c message 278 */ 279 280 if (iicstat & S3C2410_IICSTAT_LASTBIT && 281 !(i2c->msg->flags & I2C_M_IGNORE_NAK)) { 282 /* ack was not received... */ 283 284 dev_dbg(i2c->dev, "ack was not received\n"); 285 s3c24xx_i2c_stop(i2c, -ENXIO); 286 goto out_ack; 287 } 288 289 if (i2c->msg->flags & I2C_M_RD) 290 i2c->state = STATE_READ; 291 else 292 i2c->state = STATE_WRITE; 293 294 /* terminate the transfer if there is nothing to do 295 * as this is used by the i2c probe to find devices. */ 296 297 if (is_lastmsg(i2c) && i2c->msg->len == 0) { 298 s3c24xx_i2c_stop(i2c, 0); 299 goto out_ack; 300 } 301 302 if (i2c->state == STATE_READ) 303 goto prepare_read; 304 305 /* fall through to the write state, as we will need to 306 * send a byte as well */ 307 308 case STATE_WRITE: 309 /* we are writing data to the device... check for the 310 * end of the message, and if so, work out what to do 311 */ 312 313 if (!(i2c->msg->flags & I2C_M_IGNORE_NAK)) { 314 if (iicstat & S3C2410_IICSTAT_LASTBIT) { 315 dev_dbg(i2c->dev, "WRITE: No Ack\n"); 316 317 s3c24xx_i2c_stop(i2c, -ECONNREFUSED); 318 goto out_ack; 319 } 320 } 321 322 retry_write: 323 324 if (!is_msgend(i2c)) { 325 byte = i2c->msg->buf[i2c->msg_ptr++]; 326 writeb(byte, i2c->regs + S3C2410_IICDS); 327 328 /* delay after writing the byte to allow the 329 * data setup time on the bus, as writing the 330 * data to the register causes the first bit 331 * to appear on SDA, and SCL will change as 332 * soon as the interrupt is acknowledged */ 333 334 ndelay(i2c->tx_setup); 335 336 } else if (!is_lastmsg(i2c)) { 337 /* we need to go to the next i2c message */ 338 339 dev_dbg(i2c->dev, "WRITE: Next Message\n"); 340 341 i2c->msg_ptr = 0; 342 i2c->msg_idx++; 343 i2c->msg++; 344 345 /* check to see if we need to do another message */ 346 if (i2c->msg->flags & I2C_M_NOSTART) { 347 348 if (i2c->msg->flags & I2C_M_RD) { 349 /* cannot do this, the controller 350 * forces us to send a new START 351 * when we change direction */ 352 353 s3c24xx_i2c_stop(i2c, -EINVAL); 354 } 355 356 goto retry_write; 357 } else { 358 /* send the new start */ 359 s3c24xx_i2c_message_start(i2c, i2c->msg); 360 i2c->state = STATE_START; 361 } 362 363 } else { 364 /* send stop */ 365 366 s3c24xx_i2c_stop(i2c, 0); 367 } 368 break; 369 370 case STATE_READ: 371 /* we have a byte of data in the data register, do 372 * something with it, and then work out wether we are 373 * going to do any more read/write 374 */ 375 376 byte = readb(i2c->regs + S3C2410_IICDS); 377 i2c->msg->buf[i2c->msg_ptr++] = byte; 378 379 prepare_read: 380 if (is_msglast(i2c)) { 381 /* last byte of buffer */ 382 383 if (is_lastmsg(i2c)) 384 s3c24xx_i2c_disable_ack(i2c); 385 386 } else if (is_msgend(i2c)) { 387 /* ok, we've read the entire buffer, see if there 388 * is anything else we need to do */ 389 390 if (is_lastmsg(i2c)) { 391 /* last message, send stop and complete */ 392 dev_dbg(i2c->dev, "READ: Send Stop\n"); 393 394 s3c24xx_i2c_stop(i2c, 0); 395 } else { 396 /* go to the next transfer */ 397 dev_dbg(i2c->dev, "READ: Next Transfer\n"); 398 399 i2c->msg_ptr = 0; 400 i2c->msg_idx++; 401 i2c->msg++; 402 } 403 } 404 405 break; 406 } 407 408 /* acknowlegde the IRQ and get back on with the work */ 409 410 out_ack: 411 tmp = readl(i2c->regs + S3C2410_IICCON); 412 tmp &= ~S3C2410_IICCON_IRQPEND; 413 writel(tmp, i2c->regs + S3C2410_IICCON); 414 out: 415 return ret; 416 } 417 418 /* s3c24xx_i2c_irq 419 * 420 * top level IRQ servicing routine 421 */ 422 423 static irqreturn_t s3c24xx_i2c_irq(int irqno, void *dev_id) 424 { 425 struct s3c24xx_i2c *i2c = dev_id; 426 unsigned long status; 427 unsigned long tmp; 428 429 status = readl(i2c->regs + S3C2410_IICSTAT); 430 431 if (status & S3C2410_IICSTAT_ARBITR) { 432 /* deal with arbitration loss */ 433 dev_err(i2c->dev, "deal with arbitration loss\n"); 434 } 435 436 if (i2c->state == STATE_IDLE) { 437 dev_dbg(i2c->dev, "IRQ: error i2c->state == IDLE\n"); 438 439 tmp = readl(i2c->regs + S3C2410_IICCON); 440 tmp &= ~S3C2410_IICCON_IRQPEND; 441 writel(tmp, i2c->regs + S3C2410_IICCON); 442 goto out; 443 } 444 445 /* pretty much this leaves us with the fact that we've 446 * transmitted or received whatever byte we last sent */ 447 448 i2s_s3c_irq_nextbyte(i2c, status); 449 450 out: 451 return IRQ_HANDLED; 452 } 453 454 455 /* s3c24xx_i2c_set_master 456 * 457 * get the i2c bus for a master transaction 458 */ 459 460 static int s3c24xx_i2c_set_master(struct s3c24xx_i2c *i2c) 461 { 462 unsigned long iicstat; 463 int timeout = 400; 464 465 while (timeout-- > 0) { 466 iicstat = readl(i2c->regs + S3C2410_IICSTAT); 467 468 if (!(iicstat & S3C2410_IICSTAT_BUSBUSY)) 469 return 0; 470 471 msleep(1); 472 } 473 474 return -ETIMEDOUT; 475 } 476 477 /* s3c24xx_i2c_doxfer 478 * 479 * this starts an i2c transfer 480 */ 481 482 static int s3c24xx_i2c_doxfer(struct s3c24xx_i2c *i2c, 483 struct i2c_msg *msgs, int num) 484 { 485 unsigned long timeout; 486 int ret; 487 488 if (i2c->suspended) 489 return -EIO; 490 491 ret = s3c24xx_i2c_set_master(i2c); 492 if (ret != 0) { 493 dev_err(i2c->dev, "cannot get bus (error %d)\n", ret); 494 ret = -EAGAIN; 495 goto out; 496 } 497 498 spin_lock_irq(&i2c->lock); 499 500 i2c->msg = msgs; 501 i2c->msg_num = num; 502 i2c->msg_ptr = 0; 503 i2c->msg_idx = 0; 504 i2c->state = STATE_START; 505 506 s3c24xx_i2c_enable_irq(i2c); 507 s3c24xx_i2c_message_start(i2c, msgs); 508 spin_unlock_irq(&i2c->lock); 509 510 timeout = wait_event_timeout(i2c->wait, i2c->msg_num == 0, HZ * 5); 511 512 ret = i2c->msg_idx; 513 514 /* having these next two as dev_err() makes life very 515 * noisy when doing an i2cdetect */ 516 517 if (timeout == 0) 518 dev_dbg(i2c->dev, "timeout\n"); 519 else if (ret != num) 520 dev_dbg(i2c->dev, "incomplete xfer (%d)\n", ret); 521 522 /* ensure the stop has been through the bus */ 523 524 msleep(1); 525 526 out: 527 return ret; 528 } 529 530 /* s3c24xx_i2c_xfer 531 * 532 * first port of call from the i2c bus code when an message needs 533 * transferring across the i2c bus. 534 */ 535 536 static int s3c24xx_i2c_xfer(struct i2c_adapter *adap, 537 struct i2c_msg *msgs, int num) 538 { 539 struct s3c24xx_i2c *i2c = (struct s3c24xx_i2c *)adap->algo_data; 540 int retry; 541 int ret; 542 543 for (retry = 0; retry < adap->retries; retry++) { 544 545 ret = s3c24xx_i2c_doxfer(i2c, msgs, num); 546 547 if (ret != -EAGAIN) 548 return ret; 549 550 dev_dbg(i2c->dev, "Retrying transmission (%d)\n", retry); 551 552 udelay(100); 553 } 554 555 return -EREMOTEIO; 556 } 557 558 /* declare our i2c functionality */ 559 static u32 s3c24xx_i2c_func(struct i2c_adapter *adap) 560 { 561 return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_PROTOCOL_MANGLING; 562 } 563 564 /* i2c bus registration info */ 565 566 static const struct i2c_algorithm s3c24xx_i2c_algorithm = { 567 .master_xfer = s3c24xx_i2c_xfer, 568 .functionality = s3c24xx_i2c_func, 569 }; 570 571 /* s3c24xx_i2c_calcdivisor 572 * 573 * return the divisor settings for a given frequency 574 */ 575 576 static int s3c24xx_i2c_calcdivisor(unsigned long clkin, unsigned int wanted, 577 unsigned int *div1, unsigned int *divs) 578 { 579 unsigned int calc_divs = clkin / wanted; 580 unsigned int calc_div1; 581 582 if (calc_divs > (16*16)) 583 calc_div1 = 512; 584 else 585 calc_div1 = 16; 586 587 calc_divs += calc_div1-1; 588 calc_divs /= calc_div1; 589 590 if (calc_divs == 0) 591 calc_divs = 1; 592 if (calc_divs > 17) 593 calc_divs = 17; 594 595 *divs = calc_divs; 596 *div1 = calc_div1; 597 598 return clkin / (calc_divs * calc_div1); 599 } 600 601 /* s3c24xx_i2c_clockrate 602 * 603 * work out a divisor for the user requested frequency setting, 604 * either by the requested frequency, or scanning the acceptable 605 * range of frequencies until something is found 606 */ 607 608 static int s3c24xx_i2c_clockrate(struct s3c24xx_i2c *i2c, unsigned int *got) 609 { 610 struct s3c2410_platform_i2c *pdata = i2c->dev->platform_data; 611 unsigned long clkin = clk_get_rate(i2c->clk); 612 unsigned int divs, div1; 613 unsigned long target_frequency; 614 u32 iiccon; 615 int freq; 616 617 i2c->clkrate = clkin; 618 clkin /= 1000; /* clkin now in KHz */ 619 620 dev_dbg(i2c->dev, "pdata desired frequency %lu\n", pdata->frequency); 621 622 target_frequency = pdata->frequency ? pdata->frequency : 100000; 623 624 target_frequency /= 1000; /* Target frequency now in KHz */ 625 626 freq = s3c24xx_i2c_calcdivisor(clkin, target_frequency, &div1, &divs); 627 628 if (freq > target_frequency) { 629 dev_err(i2c->dev, 630 "Unable to achieve desired frequency %luKHz." \ 631 " Lowest achievable %dKHz\n", target_frequency, freq); 632 return -EINVAL; 633 } 634 635 *got = freq; 636 637 iiccon = readl(i2c->regs + S3C2410_IICCON); 638 iiccon &= ~(S3C2410_IICCON_SCALEMASK | S3C2410_IICCON_TXDIV_512); 639 iiccon |= (divs-1); 640 641 if (div1 == 512) 642 iiccon |= S3C2410_IICCON_TXDIV_512; 643 644 writel(iiccon, i2c->regs + S3C2410_IICCON); 645 646 if (s3c24xx_i2c_is2440(i2c)) { 647 unsigned long sda_delay; 648 649 if (pdata->sda_delay) { 650 sda_delay = (freq / 1000) * pdata->sda_delay; 651 sda_delay /= 1000000; 652 sda_delay = DIV_ROUND_UP(sda_delay, 5); 653 if (sda_delay > 3) 654 sda_delay = 3; 655 sda_delay |= S3C2410_IICLC_FILTER_ON; 656 } else 657 sda_delay = 0; 658 659 dev_dbg(i2c->dev, "IICLC=%08lx\n", sda_delay); 660 writel(sda_delay, i2c->regs + S3C2440_IICLC); 661 } 662 663 return 0; 664 } 665 666 #ifdef CONFIG_CPU_FREQ 667 668 #define freq_to_i2c(_n) container_of(_n, struct s3c24xx_i2c, freq_transition) 669 670 static int s3c24xx_i2c_cpufreq_transition(struct notifier_block *nb, 671 unsigned long val, void *data) 672 { 673 struct s3c24xx_i2c *i2c = freq_to_i2c(nb); 674 unsigned long flags; 675 unsigned int got; 676 int delta_f; 677 int ret; 678 679 delta_f = clk_get_rate(i2c->clk) - i2c->clkrate; 680 681 /* if we're post-change and the input clock has slowed down 682 * or at pre-change and the clock is about to speed up, then 683 * adjust our clock rate. <0 is slow, >0 speedup. 684 */ 685 686 if ((val == CPUFREQ_POSTCHANGE && delta_f < 0) || 687 (val == CPUFREQ_PRECHANGE && delta_f > 0)) { 688 spin_lock_irqsave(&i2c->lock, flags); 689 ret = s3c24xx_i2c_clockrate(i2c, &got); 690 spin_unlock_irqrestore(&i2c->lock, flags); 691 692 if (ret < 0) 693 dev_err(i2c->dev, "cannot find frequency\n"); 694 else 695 dev_info(i2c->dev, "setting freq %d\n", got); 696 } 697 698 return 0; 699 } 700 701 static inline int s3c24xx_i2c_register_cpufreq(struct s3c24xx_i2c *i2c) 702 { 703 i2c->freq_transition.notifier_call = s3c24xx_i2c_cpufreq_transition; 704 705 return cpufreq_register_notifier(&i2c->freq_transition, 706 CPUFREQ_TRANSITION_NOTIFIER); 707 } 708 709 static inline void s3c24xx_i2c_deregister_cpufreq(struct s3c24xx_i2c *i2c) 710 { 711 cpufreq_unregister_notifier(&i2c->freq_transition, 712 CPUFREQ_TRANSITION_NOTIFIER); 713 } 714 715 #else 716 static inline int s3c24xx_i2c_register_cpufreq(struct s3c24xx_i2c *i2c) 717 { 718 return 0; 719 } 720 721 static inline void s3c24xx_i2c_deregister_cpufreq(struct s3c24xx_i2c *i2c) 722 { 723 } 724 #endif 725 726 /* s3c24xx_i2c_init 727 * 728 * initialise the controller, set the IO lines and frequency 729 */ 730 731 static int s3c24xx_i2c_init(struct s3c24xx_i2c *i2c) 732 { 733 unsigned long iicon = S3C2410_IICCON_IRQEN | S3C2410_IICCON_ACKEN; 734 struct s3c2410_platform_i2c *pdata; 735 unsigned int freq; 736 737 /* get the plafrom data */ 738 739 pdata = i2c->dev->platform_data; 740 741 /* inititalise the gpio */ 742 743 if (pdata->cfg_gpio) 744 pdata->cfg_gpio(to_platform_device(i2c->dev)); 745 746 /* write slave address */ 747 748 writeb(pdata->slave_addr, i2c->regs + S3C2410_IICADD); 749 750 dev_info(i2c->dev, "slave address 0x%02x\n", pdata->slave_addr); 751 752 writel(iicon, i2c->regs + S3C2410_IICCON); 753 754 /* we need to work out the divisors for the clock... */ 755 756 if (s3c24xx_i2c_clockrate(i2c, &freq) != 0) { 757 writel(0, i2c->regs + S3C2410_IICCON); 758 dev_err(i2c->dev, "cannot meet bus frequency required\n"); 759 return -EINVAL; 760 } 761 762 /* todo - check that the i2c lines aren't being dragged anywhere */ 763 764 dev_info(i2c->dev, "bus frequency set to %d KHz\n", freq); 765 dev_dbg(i2c->dev, "S3C2410_IICCON=0x%02lx\n", iicon); 766 767 return 0; 768 } 769 770 /* s3c24xx_i2c_probe 771 * 772 * called by the bus driver when a suitable device is found 773 */ 774 775 static int s3c24xx_i2c_probe(struct platform_device *pdev) 776 { 777 struct s3c24xx_i2c *i2c; 778 struct s3c2410_platform_i2c *pdata; 779 struct resource *res; 780 int ret; 781 782 pdata = pdev->dev.platform_data; 783 if (!pdata) { 784 dev_err(&pdev->dev, "no platform data\n"); 785 return -EINVAL; 786 } 787 788 i2c = kzalloc(sizeof(struct s3c24xx_i2c), GFP_KERNEL); 789 if (!i2c) { 790 dev_err(&pdev->dev, "no memory for state\n"); 791 return -ENOMEM; 792 } 793 794 strlcpy(i2c->adap.name, "s3c2410-i2c", sizeof(i2c->adap.name)); 795 i2c->adap.owner = THIS_MODULE; 796 i2c->adap.algo = &s3c24xx_i2c_algorithm; 797 i2c->adap.retries = 2; 798 i2c->adap.class = I2C_CLASS_HWMON | I2C_CLASS_SPD; 799 i2c->tx_setup = 50; 800 801 spin_lock_init(&i2c->lock); 802 init_waitqueue_head(&i2c->wait); 803 804 /* find the clock and enable it */ 805 806 i2c->dev = &pdev->dev; 807 i2c->clk = clk_get(&pdev->dev, "i2c"); 808 if (IS_ERR(i2c->clk)) { 809 dev_err(&pdev->dev, "cannot get clock\n"); 810 ret = -ENOENT; 811 goto err_noclk; 812 } 813 814 dev_dbg(&pdev->dev, "clock source %p\n", i2c->clk); 815 816 clk_enable(i2c->clk); 817 818 /* map the registers */ 819 820 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 821 if (res == NULL) { 822 dev_err(&pdev->dev, "cannot find IO resource\n"); 823 ret = -ENOENT; 824 goto err_clk; 825 } 826 827 i2c->ioarea = request_mem_region(res->start, resource_size(res), 828 pdev->name); 829 830 if (i2c->ioarea == NULL) { 831 dev_err(&pdev->dev, "cannot request IO\n"); 832 ret = -ENXIO; 833 goto err_clk; 834 } 835 836 i2c->regs = ioremap(res->start, resource_size(res)); 837 838 if (i2c->regs == NULL) { 839 dev_err(&pdev->dev, "cannot map IO\n"); 840 ret = -ENXIO; 841 goto err_ioarea; 842 } 843 844 dev_dbg(&pdev->dev, "registers %p (%p, %p)\n", 845 i2c->regs, i2c->ioarea, res); 846 847 /* setup info block for the i2c core */ 848 849 i2c->adap.algo_data = i2c; 850 i2c->adap.dev.parent = &pdev->dev; 851 852 /* initialise the i2c controller */ 853 854 ret = s3c24xx_i2c_init(i2c); 855 if (ret != 0) 856 goto err_iomap; 857 858 /* find the IRQ for this unit (note, this relies on the init call to 859 * ensure no current IRQs pending 860 */ 861 862 i2c->irq = ret = platform_get_irq(pdev, 0); 863 if (ret <= 0) { 864 dev_err(&pdev->dev, "cannot find IRQ\n"); 865 goto err_iomap; 866 } 867 868 ret = request_irq(i2c->irq, s3c24xx_i2c_irq, IRQF_DISABLED, 869 dev_name(&pdev->dev), i2c); 870 871 if (ret != 0) { 872 dev_err(&pdev->dev, "cannot claim IRQ %d\n", i2c->irq); 873 goto err_iomap; 874 } 875 876 ret = s3c24xx_i2c_register_cpufreq(i2c); 877 if (ret < 0) { 878 dev_err(&pdev->dev, "failed to register cpufreq notifier\n"); 879 goto err_irq; 880 } 881 882 /* Note, previous versions of the driver used i2c_add_adapter() 883 * to add the bus at any number. We now pass the bus number via 884 * the platform data, so if unset it will now default to always 885 * being bus 0. 886 */ 887 888 i2c->adap.nr = pdata->bus_num; 889 890 ret = i2c_add_numbered_adapter(&i2c->adap); 891 if (ret < 0) { 892 dev_err(&pdev->dev, "failed to add bus to i2c core\n"); 893 goto err_cpufreq; 894 } 895 896 platform_set_drvdata(pdev, i2c); 897 898 dev_info(&pdev->dev, "%s: S3C I2C adapter\n", dev_name(&i2c->adap.dev)); 899 return 0; 900 901 err_cpufreq: 902 s3c24xx_i2c_deregister_cpufreq(i2c); 903 904 err_irq: 905 free_irq(i2c->irq, i2c); 906 907 err_iomap: 908 iounmap(i2c->regs); 909 910 err_ioarea: 911 release_resource(i2c->ioarea); 912 kfree(i2c->ioarea); 913 914 err_clk: 915 clk_disable(i2c->clk); 916 clk_put(i2c->clk); 917 918 err_noclk: 919 kfree(i2c); 920 return ret; 921 } 922 923 /* s3c24xx_i2c_remove 924 * 925 * called when device is removed from the bus 926 */ 927 928 static int s3c24xx_i2c_remove(struct platform_device *pdev) 929 { 930 struct s3c24xx_i2c *i2c = platform_get_drvdata(pdev); 931 932 s3c24xx_i2c_deregister_cpufreq(i2c); 933 934 i2c_del_adapter(&i2c->adap); 935 free_irq(i2c->irq, i2c); 936 937 clk_disable(i2c->clk); 938 clk_put(i2c->clk); 939 940 iounmap(i2c->regs); 941 942 release_resource(i2c->ioarea); 943 kfree(i2c->ioarea); 944 kfree(i2c); 945 946 return 0; 947 } 948 949 #ifdef CONFIG_PM 950 static int s3c24xx_i2c_suspend_noirq(struct device *dev) 951 { 952 struct platform_device *pdev = to_platform_device(dev); 953 struct s3c24xx_i2c *i2c = platform_get_drvdata(pdev); 954 955 i2c->suspended = 1; 956 957 return 0; 958 } 959 960 static int s3c24xx_i2c_resume(struct device *dev) 961 { 962 struct platform_device *pdev = to_platform_device(dev); 963 struct s3c24xx_i2c *i2c = platform_get_drvdata(pdev); 964 965 i2c->suspended = 0; 966 s3c24xx_i2c_init(i2c); 967 968 return 0; 969 } 970 971 static const struct dev_pm_ops s3c24xx_i2c_dev_pm_ops = { 972 .suspend_noirq = s3c24xx_i2c_suspend_noirq, 973 .resume = s3c24xx_i2c_resume, 974 }; 975 976 #define S3C24XX_DEV_PM_OPS (&s3c24xx_i2c_dev_pm_ops) 977 #else 978 #define S3C24XX_DEV_PM_OPS NULL 979 #endif 980 981 /* device driver for platform bus bits */ 982 983 static struct platform_device_id s3c24xx_driver_ids[] = { 984 { 985 .name = "s3c2410-i2c", 986 .driver_data = TYPE_S3C2410, 987 }, { 988 .name = "s3c2440-i2c", 989 .driver_data = TYPE_S3C2440, 990 }, { }, 991 }; 992 MODULE_DEVICE_TABLE(platform, s3c24xx_driver_ids); 993 994 static struct platform_driver s3c24xx_i2c_driver = { 995 .probe = s3c24xx_i2c_probe, 996 .remove = s3c24xx_i2c_remove, 997 .id_table = s3c24xx_driver_ids, 998 .driver = { 999 .owner = THIS_MODULE, 1000 .name = "s3c-i2c", 1001 .pm = S3C24XX_DEV_PM_OPS, 1002 }, 1003 }; 1004 1005 static int __init i2c_adap_s3c_init(void) 1006 { 1007 return platform_driver_register(&s3c24xx_i2c_driver); 1008 } 1009 subsys_initcall(i2c_adap_s3c_init); 1010 1011 static void __exit i2c_adap_s3c_exit(void) 1012 { 1013 platform_driver_unregister(&s3c24xx_i2c_driver); 1014 } 1015 module_exit(i2c_adap_s3c_exit); 1016 1017 MODULE_DESCRIPTION("S3C24XX I2C Bus driver"); 1018 MODULE_AUTHOR("Ben Dooks, <ben@simtec.co.uk>"); 1019 MODULE_LICENSE("GPL"); 1020