i2c-cpm.c 17.6 KB
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731
/*
 * Freescale CPM1/CPM2 I2C interface.
 * Copyright (c) 1999 Dan Malek (dmalek@jlc.net).
 *
 * moved into proper i2c interface;
 * Brad Parker (brad@heeltoe.com)
 *
 * Parts from dbox2_i2c.c (cvs.tuxbox.org)
 * (C) 2000-2001 Felix Domke (tmbinc@gmx.net), Gillem (htoa@gmx.net)
 *
 * (C) 2007 Montavista Software, Inc.
 * Vitaly Bordug <vitb@kernel.crashing.org>
 *
 * Converted to of_platform_device. Renamed to i2c-cpm.c.
 * (C) 2007,2008 Jochen Friedrich <jochen@scram.de>
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/delay.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/errno.h>
#include <linux/stddef.h>
#include <linux/i2c.h>
#include <linux/io.h>
#include <linux/dma-mapping.h>
#include <linux/of_device.h>
#include <linux/of_platform.h>
#include <linux/of_i2c.h>
#include <sysdev/fsl_soc.h>
#include <asm/cpm.h>

/* Try to define this if you have an older CPU (earlier than rev D4) */
/* However, better use a GPIO based bitbang driver in this case :/   */
#undef	I2C_CHIP_ERRATA

#define CPM_MAX_READ    513
#define CPM_MAXBD       4

#define I2C_EB			(0x10) /* Big endian mode */
#define I2C_EB_CPM2		(0x30) /* Big endian mode, memory snoop */

#define DPRAM_BASE		((u8 __iomem __force *)cpm_muram_addr(0))

/* I2C parameter RAM. */
struct i2c_ram {
	ushort  rbase;		/* Rx Buffer descriptor base address */
	ushort  tbase;		/* Tx Buffer descriptor base address */
	u_char  rfcr;		/* Rx function code */
	u_char  tfcr;		/* Tx function code */
	ushort  mrblr;		/* Max receive buffer length */
	uint    rstate;		/* Internal */
	uint    rdp;		/* Internal */
	ushort  rbptr;		/* Rx Buffer descriptor pointer */
	ushort  rbc;		/* Internal */
	uint    rxtmp;		/* Internal */
	uint    tstate;		/* Internal */
	uint    tdp;		/* Internal */
	ushort  tbptr;		/* Tx Buffer descriptor pointer */
	ushort  tbc;		/* Internal */
	uint    txtmp;		/* Internal */
	char    res1[4];	/* Reserved */
	ushort  rpbase;		/* Relocation pointer */
	char    res2[2];	/* Reserved */
};

#define I2COM_START	0x80
#define I2COM_MASTER	0x01
#define I2CER_TXE	0x10
#define I2CER_BUSY	0x04
#define I2CER_TXB	0x02
#define I2CER_RXB	0x01
#define I2MOD_EN	0x01

/* I2C Registers */
struct i2c_reg {
	u8	i2mod;
	u8	res1[3];
	u8	i2add;
	u8	res2[3];
	u8	i2brg;
	u8	res3[3];
	u8	i2com;
	u8	res4[3];
	u8	i2cer;
	u8	res5[3];
	u8	i2cmr;
};

struct cpm_i2c {
	char *base;
	struct platform_device *ofdev;
	struct i2c_adapter adap;
	uint dp_addr;
	int version; /* CPM1=1, CPM2=2 */
	int irq;
	int cp_command;
	int freq;
	struct i2c_reg __iomem *i2c_reg;
	struct i2c_ram __iomem *i2c_ram;
	u16 i2c_addr;
	wait_queue_head_t i2c_wait;
	cbd_t __iomem *tbase;
	cbd_t __iomem *rbase;
	u_char *txbuf[CPM_MAXBD];
	u_char *rxbuf[CPM_MAXBD];
	u32 txdma[CPM_MAXBD];
	u32 rxdma[CPM_MAXBD];
};

static irqreturn_t cpm_i2c_interrupt(int irq, void *dev_id)
{
	struct cpm_i2c *cpm;
	struct i2c_reg __iomem *i2c_reg;
	struct i2c_adapter *adap = dev_id;
	int i;

	cpm = i2c_get_adapdata(dev_id);
	i2c_reg = cpm->i2c_reg;

	/* Clear interrupt. */
	i = in_8(&i2c_reg->i2cer);
	out_8(&i2c_reg->i2cer, i);

	dev_dbg(&adap->dev, "Interrupt: %x\n", i);

	wake_up(&cpm->i2c_wait);

	return i ? IRQ_HANDLED : IRQ_NONE;
}

static void cpm_reset_i2c_params(struct cpm_i2c *cpm)
{
	struct i2c_ram __iomem *i2c_ram = cpm->i2c_ram;

	/* Set up the I2C parameters in the parameter ram. */
	out_be16(&i2c_ram->tbase, (u8 __iomem *)cpm->tbase - DPRAM_BASE);
	out_be16(&i2c_ram->rbase, (u8 __iomem *)cpm->rbase - DPRAM_BASE);

	if (cpm->version == 1) {
		out_8(&i2c_ram->tfcr, I2C_EB);
		out_8(&i2c_ram->rfcr, I2C_EB);
	} else {
		out_8(&i2c_ram->tfcr, I2C_EB_CPM2);
		out_8(&i2c_ram->rfcr, I2C_EB_CPM2);
	}

	out_be16(&i2c_ram->mrblr, CPM_MAX_READ);

	out_be32(&i2c_ram->rstate, 0);
	out_be32(&i2c_ram->rdp, 0);
	out_be16(&i2c_ram->rbptr, 0);
	out_be16(&i2c_ram->rbc, 0);
	out_be32(&i2c_ram->rxtmp, 0);
	out_be32(&i2c_ram->tstate, 0);
	out_be32(&i2c_ram->tdp, 0);
	out_be16(&i2c_ram->tbptr, 0);
	out_be16(&i2c_ram->tbc, 0);
	out_be32(&i2c_ram->txtmp, 0);
}

static void cpm_i2c_force_close(struct i2c_adapter *adap)
{
	struct cpm_i2c *cpm = i2c_get_adapdata(adap);
	struct i2c_reg __iomem *i2c_reg = cpm->i2c_reg;

	dev_dbg(&adap->dev, "cpm_i2c_force_close()\n");

	cpm_command(cpm->cp_command, CPM_CR_CLOSE_RX_BD);

	out_8(&i2c_reg->i2cmr, 0x00);	/* Disable all interrupts */
	out_8(&i2c_reg->i2cer, 0xff);
}

static void cpm_i2c_parse_message(struct i2c_adapter *adap,
	struct i2c_msg *pmsg, int num, int tx, int rx)
{
	cbd_t __iomem *tbdf;
	cbd_t __iomem *rbdf;
	u_char addr;
	u_char *tb;
	u_char *rb;
	struct cpm_i2c *cpm = i2c_get_adapdata(adap);

	tbdf = cpm->tbase + tx;
	rbdf = cpm->rbase + rx;

	addr = pmsg->addr << 1;
	if (pmsg->flags & I2C_M_RD)
		addr |= 1;

	tb = cpm->txbuf[tx];
	rb = cpm->rxbuf[rx];

	/* Align read buffer */
	rb = (u_char *) (((ulong) rb + 1) & ~1);

	tb[0] = addr;		/* Device address byte w/rw flag */

	out_be16(&tbdf->cbd_datlen, pmsg->len + 1);
	out_be16(&tbdf->cbd_sc, 0);

	if (!(pmsg->flags & I2C_M_NOSTART))
		setbits16(&tbdf->cbd_sc, BD_I2C_START);

	if (tx + 1 == num)
		setbits16(&tbdf->cbd_sc, BD_SC_LAST | BD_SC_WRAP);

	if (pmsg->flags & I2C_M_RD) {
		/*
		 * To read, we need an empty buffer of the proper length.
		 * All that is used is the first byte for address, the remainder
		 * is just used for timing (and doesn't really have to exist).
		 */

		dev_dbg(&adap->dev, "cpm_i2c_read(abyte=0x%x)\n", addr);

		out_be16(&rbdf->cbd_datlen, 0);
		out_be16(&rbdf->cbd_sc, BD_SC_EMPTY | BD_SC_INTRPT);

		if (rx + 1 == CPM_MAXBD)
			setbits16(&rbdf->cbd_sc, BD_SC_WRAP);

		eieio();
		setbits16(&tbdf->cbd_sc, BD_SC_READY);
	} else {
		dev_dbg(&adap->dev, "cpm_i2c_write(abyte=0x%x)\n", addr);

		memcpy(tb+1, pmsg->buf, pmsg->len);

		eieio();
		setbits16(&tbdf->cbd_sc, BD_SC_READY | BD_SC_INTRPT);
	}
}

static int cpm_i2c_check_message(struct i2c_adapter *adap,
	struct i2c_msg *pmsg, int tx, int rx)
{
	cbd_t __iomem *tbdf;
	cbd_t __iomem *rbdf;
	u_char *tb;
	u_char *rb;
	struct cpm_i2c *cpm = i2c_get_adapdata(adap);

	tbdf = cpm->tbase + tx;
	rbdf = cpm->rbase + rx;

	tb = cpm->txbuf[tx];
	rb = cpm->rxbuf[rx];

	/* Align read buffer */
	rb = (u_char *) (((uint) rb + 1) & ~1);

	eieio();
	if (pmsg->flags & I2C_M_RD) {
		dev_dbg(&adap->dev, "tx sc 0x%04x, rx sc 0x%04x\n",
			in_be16(&tbdf->cbd_sc), in_be16(&rbdf->cbd_sc));

		if (in_be16(&tbdf->cbd_sc) & BD_SC_NAK) {
			dev_dbg(&adap->dev, "I2C read; No ack\n");
			return -ENXIO;
		}
		if (in_be16(&rbdf->cbd_sc) & BD_SC_EMPTY) {
			dev_err(&adap->dev,
				"I2C read; complete but rbuf empty\n");
			return -EREMOTEIO;
		}
		if (in_be16(&rbdf->cbd_sc) & BD_SC_OV) {
			dev_err(&adap->dev, "I2C read; Overrun\n");
			return -EREMOTEIO;
		}
		memcpy(pmsg->buf, rb, pmsg->len);
	} else {
		dev_dbg(&adap->dev, "tx sc %d 0x%04x\n", tx,
			in_be16(&tbdf->cbd_sc));

		if (in_be16(&tbdf->cbd_sc) & BD_SC_NAK) {
			dev_dbg(&adap->dev, "I2C write; No ack\n");
			return -ENXIO;
		}
		if (in_be16(&tbdf->cbd_sc) & BD_SC_UN) {
			dev_err(&adap->dev, "I2C write; Underrun\n");
			return -EIO;
		}
		if (in_be16(&tbdf->cbd_sc) & BD_SC_CL) {
			dev_err(&adap->dev, "I2C write; Collision\n");
			return -EIO;
		}
	}
	return 0;
}

static int cpm_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
{
	struct cpm_i2c *cpm = i2c_get_adapdata(adap);
	struct i2c_reg __iomem *i2c_reg = cpm->i2c_reg;
	struct i2c_ram __iomem *i2c_ram = cpm->i2c_ram;
	struct i2c_msg *pmsg;
	int ret, i;
	int tptr;
	int rptr;
	cbd_t __iomem *tbdf;
	cbd_t __iomem *rbdf;

	if (num > CPM_MAXBD)
		return -EINVAL;

	/* Check if we have any oversized READ requests */
	for (i = 0; i < num; i++) {
		pmsg = &msgs[i];
		if (pmsg->len >= CPM_MAX_READ)
			return -EINVAL;
	}

	/* Reset to use first buffer */
	out_be16(&i2c_ram->rbptr, in_be16(&i2c_ram->rbase));
	out_be16(&i2c_ram->tbptr, in_be16(&i2c_ram->tbase));

	tbdf = cpm->tbase;
	rbdf = cpm->rbase;

	tptr = 0;
	rptr = 0;

	while (tptr < num) {
		pmsg = &msgs[tptr];
		dev_dbg(&adap->dev, "R: %d T: %d\n", rptr, tptr);

		cpm_i2c_parse_message(adap, pmsg, num, tptr, rptr);
		if (pmsg->flags & I2C_M_RD)
			rptr++;
		tptr++;
	}
	/* Start transfer now */
	/* Enable RX/TX/Error interupts */
	out_8(&i2c_reg->i2cmr, I2CER_TXE | I2CER_TXB | I2CER_RXB);
	out_8(&i2c_reg->i2cer, 0xff);	/* Clear interrupt status */
	/* Chip bug, set enable here */
	setbits8(&i2c_reg->i2mod, I2MOD_EN);	/* Enable */
	/* Begin transmission */
	setbits8(&i2c_reg->i2com, I2COM_START);

	tptr = 0;
	rptr = 0;

	while (tptr < num) {
		/* Check for outstanding messages */
		dev_dbg(&adap->dev, "test ready.\n");
		pmsg = &msgs[tptr];
		if (pmsg->flags & I2C_M_RD)
			ret = wait_event_timeout(cpm->i2c_wait,
				(in_be16(&tbdf[tptr].cbd_sc) & BD_SC_NAK) ||
				!(in_be16(&rbdf[rptr].cbd_sc) & BD_SC_EMPTY),
				1 * HZ);
		else
			ret = wait_event_timeout(cpm->i2c_wait,
				!(in_be16(&tbdf[tptr].cbd_sc) & BD_SC_READY),
				1 * HZ);
		if (ret == 0) {
			ret = -EREMOTEIO;
			dev_err(&adap->dev, "I2C transfer: timeout\n");
			goto out_err;
		}
		if (ret > 0) {
			dev_dbg(&adap->dev, "ready.\n");
			ret = cpm_i2c_check_message(adap, pmsg, tptr, rptr);
			tptr++;
			if (pmsg->flags & I2C_M_RD)
				rptr++;
			if (ret)
				goto out_err;
		}
	}
#ifdef I2C_CHIP_ERRATA
	/*
	 * Chip errata, clear enable. This is not needed on rev D4 CPUs.
	 * Disabling I2C too early may cause too short stop condition
	 */
	udelay(4);
	clrbits8(&i2c_reg->i2mod, I2MOD_EN);
#endif
	return (num);

out_err:
	cpm_i2c_force_close(adap);
#ifdef I2C_CHIP_ERRATA
	/*
	 * Chip errata, clear enable. This is not needed on rev D4 CPUs.
	 */
	clrbits8(&i2c_reg->i2mod, I2MOD_EN);
#endif
	return ret;
}

static u32 cpm_i2c_func(struct i2c_adapter *adap)
{
	return I2C_FUNC_I2C | (I2C_FUNC_SMBUS_EMUL & ~I2C_FUNC_SMBUS_QUICK);
}

/* -----exported algorithm data: -------------------------------------	*/

static const struct i2c_algorithm cpm_i2c_algo = {
	.master_xfer = cpm_i2c_xfer,
	.functionality = cpm_i2c_func,
};

static const struct i2c_adapter cpm_ops = {
	.owner		= THIS_MODULE,
	.name		= "i2c-cpm",
	.algo		= &cpm_i2c_algo,
};

static int __devinit cpm_i2c_setup(struct cpm_i2c *cpm)
{
	struct platform_device *ofdev = cpm->ofdev;
	const u32 *data;
	int len, ret, i;
	void __iomem *i2c_base;
	cbd_t __iomem *tbdf;
	cbd_t __iomem *rbdf;
	unsigned char brg;

	dev_dbg(&cpm->ofdev->dev, "cpm_i2c_setup()\n");

	init_waitqueue_head(&cpm->i2c_wait);

	cpm->irq = of_irq_to_resource(ofdev->dev.of_node, 0, NULL);
	if (!cpm->irq)
		return -EINVAL;

	/* Install interrupt handler. */
	ret = request_irq(cpm->irq, cpm_i2c_interrupt, 0, "cpm_i2c",
			  &cpm->adap);
	if (ret)
		return ret;

	/* I2C parameter RAM */
	i2c_base = of_iomap(ofdev->dev.of_node, 1);
	if (i2c_base == NULL) {
		ret = -EINVAL;
		goto out_irq;
	}

	if (of_device_is_compatible(ofdev->dev.of_node, "fsl,cpm1-i2c")) {

		/* Check for and use a microcode relocation patch. */
		cpm->i2c_ram = i2c_base;
		cpm->i2c_addr = in_be16(&cpm->i2c_ram->rpbase);

		/*
		 * Maybe should use cpm_muram_alloc instead of hardcoding
		 * this in micropatch.c
		 */
		if (cpm->i2c_addr) {
			cpm->i2c_ram = cpm_muram_addr(cpm->i2c_addr);
			iounmap(i2c_base);
		}

		cpm->version = 1;

	} else if (of_device_is_compatible(ofdev->dev.of_node, "fsl,cpm2-i2c")) {
		cpm->i2c_addr = cpm_muram_alloc(sizeof(struct i2c_ram), 64);
		cpm->i2c_ram = cpm_muram_addr(cpm->i2c_addr);
		out_be16(i2c_base, cpm->i2c_addr);
		iounmap(i2c_base);

		cpm->version = 2;

	} else {
		iounmap(i2c_base);
		ret = -EINVAL;
		goto out_irq;
	}

	/* I2C control/status registers */
	cpm->i2c_reg = of_iomap(ofdev->dev.of_node, 0);
	if (cpm->i2c_reg == NULL) {
		ret = -EINVAL;
		goto out_ram;
	}

	data = of_get_property(ofdev->dev.of_node, "fsl,cpm-command", &len);
	if (!data || len != 4) {
		ret = -EINVAL;
		goto out_reg;
	}
	cpm->cp_command = *data;

	data = of_get_property(ofdev->dev.of_node, "linux,i2c-class", &len);
	if (data && len == 4)
		cpm->adap.class = *data;

	data = of_get_property(ofdev->dev.of_node, "clock-frequency", &len);
	if (data && len == 4)
		cpm->freq = *data;
	else
		cpm->freq = 60000; /* use 60kHz i2c clock by default */

	/*
	 * Allocate space for CPM_MAXBD transmit and receive buffer
	 * descriptors in the DP ram.
	 */
	cpm->dp_addr = cpm_muram_alloc(sizeof(cbd_t) * 2 * CPM_MAXBD, 8);
	if (!cpm->dp_addr) {
		ret = -ENOMEM;
		goto out_reg;
	}

	cpm->tbase = cpm_muram_addr(cpm->dp_addr);
	cpm->rbase = cpm_muram_addr(cpm->dp_addr + sizeof(cbd_t) * CPM_MAXBD);

	/* Allocate TX and RX buffers */

	tbdf = cpm->tbase;
	rbdf = cpm->rbase;

	for (i = 0; i < CPM_MAXBD; i++) {
		cpm->rxbuf[i] = dma_alloc_coherent(&cpm->ofdev->dev,
						   CPM_MAX_READ + 1,
						   &cpm->rxdma[i], GFP_KERNEL);
		if (!cpm->rxbuf[i]) {
			ret = -ENOMEM;
			goto out_muram;
		}
		out_be32(&rbdf[i].cbd_bufaddr, ((cpm->rxdma[i] + 1) & ~1));

		cpm->txbuf[i] = (unsigned char *)dma_alloc_coherent(&cpm->ofdev->dev, CPM_MAX_READ + 1, &cpm->txdma[i], GFP_KERNEL);
		if (!cpm->txbuf[i]) {
			ret = -ENOMEM;
			goto out_muram;
		}
		out_be32(&tbdf[i].cbd_bufaddr, cpm->txdma[i]);
	}

	/* Initialize Tx/Rx parameters. */

	cpm_reset_i2c_params(cpm);

	dev_dbg(&cpm->ofdev->dev, "i2c_ram 0x%p, i2c_addr 0x%04x, freq %d\n",
		cpm->i2c_ram, cpm->i2c_addr, cpm->freq);
	dev_dbg(&cpm->ofdev->dev, "tbase 0x%04x, rbase 0x%04x\n",
		(u8 __iomem *)cpm->tbase - DPRAM_BASE,
		(u8 __iomem *)cpm->rbase - DPRAM_BASE);

	cpm_command(cpm->cp_command, CPM_CR_INIT_TRX);

	/*
	 * Select an invalid address. Just make sure we don't use loopback mode
	 */
	out_8(&cpm->i2c_reg->i2add, 0x7f << 1);

	/*
	 * PDIV is set to 00 in i2mod, so brgclk/32 is used as input to the
	 * i2c baud rate generator. This is divided by 2 x (DIV + 3) to get
	 * the actual i2c bus frequency.
	 */
	brg = get_brgfreq() / (32 * 2 * cpm->freq) - 3;
	out_8(&cpm->i2c_reg->i2brg, brg);

	out_8(&cpm->i2c_reg->i2mod, 0x00);
	out_8(&cpm->i2c_reg->i2com, I2COM_MASTER);	/* Master mode */

	/* Disable interrupts. */
	out_8(&cpm->i2c_reg->i2cmr, 0);
	out_8(&cpm->i2c_reg->i2cer, 0xff);

	return 0;

out_muram:
	for (i = 0; i < CPM_MAXBD; i++) {
		if (cpm->rxbuf[i])
			dma_free_coherent(&cpm->ofdev->dev, CPM_MAX_READ + 1,
				cpm->rxbuf[i], cpm->rxdma[i]);
		if (cpm->txbuf[i])
			dma_free_coherent(&cpm->ofdev->dev, CPM_MAX_READ + 1,
				cpm->txbuf[i], cpm->txdma[i]);
	}
	cpm_muram_free(cpm->dp_addr);
out_reg:
	iounmap(cpm->i2c_reg);
out_ram:
	if ((cpm->version == 1) && (!cpm->i2c_addr))
		iounmap(cpm->i2c_ram);
	if (cpm->version == 2)
		cpm_muram_free(cpm->i2c_addr);
out_irq:
	free_irq(cpm->irq, &cpm->adap);
	return ret;
}

static void cpm_i2c_shutdown(struct cpm_i2c *cpm)
{
	int i;

	/* Shut down I2C. */
	clrbits8(&cpm->i2c_reg->i2mod, I2MOD_EN);

	/* Disable interrupts */
	out_8(&cpm->i2c_reg->i2cmr, 0);
	out_8(&cpm->i2c_reg->i2cer, 0xff);

	free_irq(cpm->irq, &cpm->adap);

	/* Free all memory */
	for (i = 0; i < CPM_MAXBD; i++) {
		dma_free_coherent(&cpm->ofdev->dev, CPM_MAX_READ + 1,
			cpm->rxbuf[i], cpm->rxdma[i]);
		dma_free_coherent(&cpm->ofdev->dev, CPM_MAX_READ + 1,
			cpm->txbuf[i], cpm->txdma[i]);
	}

	cpm_muram_free(cpm->dp_addr);
	iounmap(cpm->i2c_reg);

	if ((cpm->version == 1) && (!cpm->i2c_addr))
		iounmap(cpm->i2c_ram);
	if (cpm->version == 2)
		cpm_muram_free(cpm->i2c_addr);
}

static int __devinit cpm_i2c_probe(struct platform_device *ofdev)
{
	int result, len;
	struct cpm_i2c *cpm;
	const u32 *data;

	cpm = kzalloc(sizeof(struct cpm_i2c), GFP_KERNEL);
	if (!cpm)
		return -ENOMEM;

	cpm->ofdev = ofdev;

	dev_set_drvdata(&ofdev->dev, cpm);

	cpm->adap = cpm_ops;
	i2c_set_adapdata(&cpm->adap, cpm);
	cpm->adap.dev.parent = &ofdev->dev;
	cpm->adap.dev.of_node = of_node_get(ofdev->dev.of_node);

	result = cpm_i2c_setup(cpm);
	if (result) {
		dev_err(&ofdev->dev, "Unable to init hardware\n");
		goto out_free;
	}

	/* register new adapter to i2c module... */

	data = of_get_property(ofdev->dev.of_node, "linux,i2c-index", &len);
	cpm->adap.nr = (data && len == 4) ? be32_to_cpup(data) : -1;
	result = i2c_add_numbered_adapter(&cpm->adap);

	if (result < 0) {
		dev_err(&ofdev->dev, "Unable to register with I2C\n");
		goto out_shut;
	}

	dev_dbg(&ofdev->dev, "hw routines for %s registered.\n",
		cpm->adap.name);

	/*
	 * register OF I2C devices
	 */
	of_i2c_register_devices(&cpm->adap);

	return 0;
out_shut:
	cpm_i2c_shutdown(cpm);
out_free:
	dev_set_drvdata(&ofdev->dev, NULL);
	kfree(cpm);

	return result;
}

static int __devexit cpm_i2c_remove(struct platform_device *ofdev)
{
	struct cpm_i2c *cpm = dev_get_drvdata(&ofdev->dev);

	i2c_del_adapter(&cpm->adap);

	cpm_i2c_shutdown(cpm);

	dev_set_drvdata(&ofdev->dev, NULL);
	kfree(cpm);

	return 0;
}

static const struct of_device_id cpm_i2c_match[] = {
	{
		.compatible = "fsl,cpm1-i2c",
	},
	{
		.compatible = "fsl,cpm2-i2c",
	},
	{},
};

MODULE_DEVICE_TABLE(of, cpm_i2c_match);

static struct platform_driver cpm_i2c_driver = {
	.probe		= cpm_i2c_probe,
	.remove		= __devexit_p(cpm_i2c_remove),
	.driver = {
		.name = "fsl-i2c-cpm",
		.owner = THIS_MODULE,
		.of_match_table = cpm_i2c_match,
	},
};

module_platform_driver(cpm_i2c_driver);

MODULE_AUTHOR("Jochen Friedrich <jochen@scram.de>");
MODULE_DESCRIPTION("I2C-Bus adapter routines for CPM boards");
MODULE_LICENSE("GPL");