xref: /openbmc/linux/drivers/i2c/busses/i2c-cpm.c (revision 12eb4683)
1 /*
2  * Freescale CPM1/CPM2 I2C interface.
3  * Copyright (c) 1999 Dan Malek (dmalek@jlc.net).
4  *
5  * moved into proper i2c interface;
6  * Brad Parker (brad@heeltoe.com)
7  *
8  * Parts from dbox2_i2c.c (cvs.tuxbox.org)
9  * (C) 2000-2001 Felix Domke (tmbinc@gmx.net), Gillem (htoa@gmx.net)
10  *
11  * (C) 2007 Montavista Software, Inc.
12  * Vitaly Bordug <vitb@kernel.crashing.org>
13  *
14  * Converted to of_platform_device. Renamed to i2c-cpm.c.
15  * (C) 2007,2008 Jochen Friedrich <jochen@scram.de>
16  *
17  *  This program is free software; you can redistribute it and/or modify
18  *  it under the terms of the GNU General Public License as published by
19  *  the Free Software Foundation; either version 2 of the License, or
20  *  (at your option) any later version.
21  *
22  *  This program is distributed in the hope that it will be useful,
23  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
24  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
25  *  GNU General Public License for more details.
26  *
27  *  You should have received a copy of the GNU General Public License
28  *  along with this program; if not, write to the Free Software
29  *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
30  */
31 
32 #include <linux/kernel.h>
33 #include <linux/module.h>
34 #include <linux/delay.h>
35 #include <linux/slab.h>
36 #include <linux/init.h>
37 #include <linux/interrupt.h>
38 #include <linux/errno.h>
39 #include <linux/stddef.h>
40 #include <linux/i2c.h>
41 #include <linux/io.h>
42 #include <linux/dma-mapping.h>
43 #include <linux/of_device.h>
44 #include <linux/of_platform.h>
45 #include <sysdev/fsl_soc.h>
46 #include <asm/cpm.h>
47 
48 /* Try to define this if you have an older CPU (earlier than rev D4) */
49 /* However, better use a GPIO based bitbang driver in this case :/   */
50 #undef	I2C_CHIP_ERRATA
51 
52 #define CPM_MAX_READ    513
53 #define CPM_MAXBD       4
54 
55 #define I2C_EB			(0x10) /* Big endian mode */
56 #define I2C_EB_CPM2		(0x30) /* Big endian mode, memory snoop */
57 
58 #define DPRAM_BASE		((u8 __iomem __force *)cpm_muram_addr(0))
59 
60 /* I2C parameter RAM. */
61 struct i2c_ram {
62 	ushort  rbase;		/* Rx Buffer descriptor base address */
63 	ushort  tbase;		/* Tx Buffer descriptor base address */
64 	u_char  rfcr;		/* Rx function code */
65 	u_char  tfcr;		/* Tx function code */
66 	ushort  mrblr;		/* Max receive buffer length */
67 	uint    rstate;		/* Internal */
68 	uint    rdp;		/* Internal */
69 	ushort  rbptr;		/* Rx Buffer descriptor pointer */
70 	ushort  rbc;		/* Internal */
71 	uint    rxtmp;		/* Internal */
72 	uint    tstate;		/* Internal */
73 	uint    tdp;		/* Internal */
74 	ushort  tbptr;		/* Tx Buffer descriptor pointer */
75 	ushort  tbc;		/* Internal */
76 	uint    txtmp;		/* Internal */
77 	char    res1[4];	/* Reserved */
78 	ushort  rpbase;		/* Relocation pointer */
79 	char    res2[2];	/* Reserved */
80 };
81 
82 #define I2COM_START	0x80
83 #define I2COM_MASTER	0x01
84 #define I2CER_TXE	0x10
85 #define I2CER_BUSY	0x04
86 #define I2CER_TXB	0x02
87 #define I2CER_RXB	0x01
88 #define I2MOD_EN	0x01
89 
90 /* I2C Registers */
91 struct i2c_reg {
92 	u8	i2mod;
93 	u8	res1[3];
94 	u8	i2add;
95 	u8	res2[3];
96 	u8	i2brg;
97 	u8	res3[3];
98 	u8	i2com;
99 	u8	res4[3];
100 	u8	i2cer;
101 	u8	res5[3];
102 	u8	i2cmr;
103 };
104 
105 struct cpm_i2c {
106 	char *base;
107 	struct platform_device *ofdev;
108 	struct i2c_adapter adap;
109 	uint dp_addr;
110 	int version; /* CPM1=1, CPM2=2 */
111 	int irq;
112 	int cp_command;
113 	int freq;
114 	struct i2c_reg __iomem *i2c_reg;
115 	struct i2c_ram __iomem *i2c_ram;
116 	u16 i2c_addr;
117 	wait_queue_head_t i2c_wait;
118 	cbd_t __iomem *tbase;
119 	cbd_t __iomem *rbase;
120 	u_char *txbuf[CPM_MAXBD];
121 	u_char *rxbuf[CPM_MAXBD];
122 	u32 txdma[CPM_MAXBD];
123 	u32 rxdma[CPM_MAXBD];
124 };
125 
126 static irqreturn_t cpm_i2c_interrupt(int irq, void *dev_id)
127 {
128 	struct cpm_i2c *cpm;
129 	struct i2c_reg __iomem *i2c_reg;
130 	struct i2c_adapter *adap = dev_id;
131 	int i;
132 
133 	cpm = i2c_get_adapdata(dev_id);
134 	i2c_reg = cpm->i2c_reg;
135 
136 	/* Clear interrupt. */
137 	i = in_8(&i2c_reg->i2cer);
138 	out_8(&i2c_reg->i2cer, i);
139 
140 	dev_dbg(&adap->dev, "Interrupt: %x\n", i);
141 
142 	wake_up(&cpm->i2c_wait);
143 
144 	return i ? IRQ_HANDLED : IRQ_NONE;
145 }
146 
147 static void cpm_reset_i2c_params(struct cpm_i2c *cpm)
148 {
149 	struct i2c_ram __iomem *i2c_ram = cpm->i2c_ram;
150 
151 	/* Set up the I2C parameters in the parameter ram. */
152 	out_be16(&i2c_ram->tbase, (u8 __iomem *)cpm->tbase - DPRAM_BASE);
153 	out_be16(&i2c_ram->rbase, (u8 __iomem *)cpm->rbase - DPRAM_BASE);
154 
155 	if (cpm->version == 1) {
156 		out_8(&i2c_ram->tfcr, I2C_EB);
157 		out_8(&i2c_ram->rfcr, I2C_EB);
158 	} else {
159 		out_8(&i2c_ram->tfcr, I2C_EB_CPM2);
160 		out_8(&i2c_ram->rfcr, I2C_EB_CPM2);
161 	}
162 
163 	out_be16(&i2c_ram->mrblr, CPM_MAX_READ);
164 
165 	out_be32(&i2c_ram->rstate, 0);
166 	out_be32(&i2c_ram->rdp, 0);
167 	out_be16(&i2c_ram->rbptr, 0);
168 	out_be16(&i2c_ram->rbc, 0);
169 	out_be32(&i2c_ram->rxtmp, 0);
170 	out_be32(&i2c_ram->tstate, 0);
171 	out_be32(&i2c_ram->tdp, 0);
172 	out_be16(&i2c_ram->tbptr, 0);
173 	out_be16(&i2c_ram->tbc, 0);
174 	out_be32(&i2c_ram->txtmp, 0);
175 }
176 
177 static void cpm_i2c_force_close(struct i2c_adapter *adap)
178 {
179 	struct cpm_i2c *cpm = i2c_get_adapdata(adap);
180 	struct i2c_reg __iomem *i2c_reg = cpm->i2c_reg;
181 
182 	dev_dbg(&adap->dev, "cpm_i2c_force_close()\n");
183 
184 	cpm_command(cpm->cp_command, CPM_CR_CLOSE_RX_BD);
185 
186 	out_8(&i2c_reg->i2cmr, 0x00);	/* Disable all interrupts */
187 	out_8(&i2c_reg->i2cer, 0xff);
188 }
189 
190 static void cpm_i2c_parse_message(struct i2c_adapter *adap,
191 	struct i2c_msg *pmsg, int num, int tx, int rx)
192 {
193 	cbd_t __iomem *tbdf;
194 	cbd_t __iomem *rbdf;
195 	u_char addr;
196 	u_char *tb;
197 	u_char *rb;
198 	struct cpm_i2c *cpm = i2c_get_adapdata(adap);
199 
200 	tbdf = cpm->tbase + tx;
201 	rbdf = cpm->rbase + rx;
202 
203 	addr = pmsg->addr << 1;
204 	if (pmsg->flags & I2C_M_RD)
205 		addr |= 1;
206 
207 	tb = cpm->txbuf[tx];
208 	rb = cpm->rxbuf[rx];
209 
210 	/* Align read buffer */
211 	rb = (u_char *) (((ulong) rb + 1) & ~1);
212 
213 	tb[0] = addr;		/* Device address byte w/rw flag */
214 
215 	out_be16(&tbdf->cbd_datlen, pmsg->len + 1);
216 	out_be16(&tbdf->cbd_sc, 0);
217 
218 	if (!(pmsg->flags & I2C_M_NOSTART))
219 		setbits16(&tbdf->cbd_sc, BD_I2C_START);
220 
221 	if (tx + 1 == num)
222 		setbits16(&tbdf->cbd_sc, BD_SC_LAST | BD_SC_WRAP);
223 
224 	if (pmsg->flags & I2C_M_RD) {
225 		/*
226 		 * To read, we need an empty buffer of the proper length.
227 		 * All that is used is the first byte for address, the remainder
228 		 * is just used for timing (and doesn't really have to exist).
229 		 */
230 
231 		dev_dbg(&adap->dev, "cpm_i2c_read(abyte=0x%x)\n", addr);
232 
233 		out_be16(&rbdf->cbd_datlen, 0);
234 		out_be16(&rbdf->cbd_sc, BD_SC_EMPTY | BD_SC_INTRPT);
235 
236 		if (rx + 1 == CPM_MAXBD)
237 			setbits16(&rbdf->cbd_sc, BD_SC_WRAP);
238 
239 		eieio();
240 		setbits16(&tbdf->cbd_sc, BD_SC_READY);
241 	} else {
242 		dev_dbg(&adap->dev, "cpm_i2c_write(abyte=0x%x)\n", addr);
243 
244 		memcpy(tb+1, pmsg->buf, pmsg->len);
245 
246 		eieio();
247 		setbits16(&tbdf->cbd_sc, BD_SC_READY | BD_SC_INTRPT);
248 	}
249 }
250 
251 static int cpm_i2c_check_message(struct i2c_adapter *adap,
252 	struct i2c_msg *pmsg, int tx, int rx)
253 {
254 	cbd_t __iomem *tbdf;
255 	cbd_t __iomem *rbdf;
256 	u_char *tb;
257 	u_char *rb;
258 	struct cpm_i2c *cpm = i2c_get_adapdata(adap);
259 
260 	tbdf = cpm->tbase + tx;
261 	rbdf = cpm->rbase + rx;
262 
263 	tb = cpm->txbuf[tx];
264 	rb = cpm->rxbuf[rx];
265 
266 	/* Align read buffer */
267 	rb = (u_char *) (((uint) rb + 1) & ~1);
268 
269 	eieio();
270 	if (pmsg->flags & I2C_M_RD) {
271 		dev_dbg(&adap->dev, "tx sc 0x%04x, rx sc 0x%04x\n",
272 			in_be16(&tbdf->cbd_sc), in_be16(&rbdf->cbd_sc));
273 
274 		if (in_be16(&tbdf->cbd_sc) & BD_SC_NAK) {
275 			dev_dbg(&adap->dev, "I2C read; No ack\n");
276 			return -ENXIO;
277 		}
278 		if (in_be16(&rbdf->cbd_sc) & BD_SC_EMPTY) {
279 			dev_err(&adap->dev,
280 				"I2C read; complete but rbuf empty\n");
281 			return -EREMOTEIO;
282 		}
283 		if (in_be16(&rbdf->cbd_sc) & BD_SC_OV) {
284 			dev_err(&adap->dev, "I2C read; Overrun\n");
285 			return -EREMOTEIO;
286 		}
287 		memcpy(pmsg->buf, rb, pmsg->len);
288 	} else {
289 		dev_dbg(&adap->dev, "tx sc %d 0x%04x\n", tx,
290 			in_be16(&tbdf->cbd_sc));
291 
292 		if (in_be16(&tbdf->cbd_sc) & BD_SC_NAK) {
293 			dev_dbg(&adap->dev, "I2C write; No ack\n");
294 			return -ENXIO;
295 		}
296 		if (in_be16(&tbdf->cbd_sc) & BD_SC_UN) {
297 			dev_err(&adap->dev, "I2C write; Underrun\n");
298 			return -EIO;
299 		}
300 		if (in_be16(&tbdf->cbd_sc) & BD_SC_CL) {
301 			dev_err(&adap->dev, "I2C write; Collision\n");
302 			return -EIO;
303 		}
304 	}
305 	return 0;
306 }
307 
308 static int cpm_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
309 {
310 	struct cpm_i2c *cpm = i2c_get_adapdata(adap);
311 	struct i2c_reg __iomem *i2c_reg = cpm->i2c_reg;
312 	struct i2c_ram __iomem *i2c_ram = cpm->i2c_ram;
313 	struct i2c_msg *pmsg;
314 	int ret, i;
315 	int tptr;
316 	int rptr;
317 	cbd_t __iomem *tbdf;
318 	cbd_t __iomem *rbdf;
319 
320 	if (num > CPM_MAXBD)
321 		return -EINVAL;
322 
323 	/* Check if we have any oversized READ requests */
324 	for (i = 0; i < num; i++) {
325 		pmsg = &msgs[i];
326 		if (pmsg->len >= CPM_MAX_READ)
327 			return -EINVAL;
328 	}
329 
330 	/* Reset to use first buffer */
331 	out_be16(&i2c_ram->rbptr, in_be16(&i2c_ram->rbase));
332 	out_be16(&i2c_ram->tbptr, in_be16(&i2c_ram->tbase));
333 
334 	tbdf = cpm->tbase;
335 	rbdf = cpm->rbase;
336 
337 	tptr = 0;
338 	rptr = 0;
339 
340 	/*
341 	 * If there was a collision in the last i2c transaction,
342 	 * Set I2COM_MASTER as it was cleared during collision.
343 	 */
344 	if (in_be16(&tbdf->cbd_sc) & BD_SC_CL) {
345 		out_8(&cpm->i2c_reg->i2com, I2COM_MASTER);
346 	}
347 
348 	while (tptr < num) {
349 		pmsg = &msgs[tptr];
350 		dev_dbg(&adap->dev, "R: %d T: %d\n", rptr, tptr);
351 
352 		cpm_i2c_parse_message(adap, pmsg, num, tptr, rptr);
353 		if (pmsg->flags & I2C_M_RD)
354 			rptr++;
355 		tptr++;
356 	}
357 	/* Start transfer now */
358 	/* Enable RX/TX/Error interupts */
359 	out_8(&i2c_reg->i2cmr, I2CER_TXE | I2CER_TXB | I2CER_RXB);
360 	out_8(&i2c_reg->i2cer, 0xff);	/* Clear interrupt status */
361 	/* Chip bug, set enable here */
362 	setbits8(&i2c_reg->i2mod, I2MOD_EN);	/* Enable */
363 	/* Begin transmission */
364 	setbits8(&i2c_reg->i2com, I2COM_START);
365 
366 	tptr = 0;
367 	rptr = 0;
368 
369 	while (tptr < num) {
370 		/* Check for outstanding messages */
371 		dev_dbg(&adap->dev, "test ready.\n");
372 		pmsg = &msgs[tptr];
373 		if (pmsg->flags & I2C_M_RD)
374 			ret = wait_event_timeout(cpm->i2c_wait,
375 				(in_be16(&tbdf[tptr].cbd_sc) & BD_SC_NAK) ||
376 				!(in_be16(&rbdf[rptr].cbd_sc) & BD_SC_EMPTY),
377 				1 * HZ);
378 		else
379 			ret = wait_event_timeout(cpm->i2c_wait,
380 				!(in_be16(&tbdf[tptr].cbd_sc) & BD_SC_READY),
381 				1 * HZ);
382 		if (ret == 0) {
383 			ret = -EREMOTEIO;
384 			dev_err(&adap->dev, "I2C transfer: timeout\n");
385 			goto out_err;
386 		}
387 		if (ret > 0) {
388 			dev_dbg(&adap->dev, "ready.\n");
389 			ret = cpm_i2c_check_message(adap, pmsg, tptr, rptr);
390 			tptr++;
391 			if (pmsg->flags & I2C_M_RD)
392 				rptr++;
393 			if (ret)
394 				goto out_err;
395 		}
396 	}
397 #ifdef I2C_CHIP_ERRATA
398 	/*
399 	 * Chip errata, clear enable. This is not needed on rev D4 CPUs.
400 	 * Disabling I2C too early may cause too short stop condition
401 	 */
402 	udelay(4);
403 	clrbits8(&i2c_reg->i2mod, I2MOD_EN);
404 #endif
405 	return (num);
406 
407 out_err:
408 	cpm_i2c_force_close(adap);
409 #ifdef I2C_CHIP_ERRATA
410 	/*
411 	 * Chip errata, clear enable. This is not needed on rev D4 CPUs.
412 	 */
413 	clrbits8(&i2c_reg->i2mod, I2MOD_EN);
414 #endif
415 	return ret;
416 }
417 
418 static u32 cpm_i2c_func(struct i2c_adapter *adap)
419 {
420 	return I2C_FUNC_I2C | (I2C_FUNC_SMBUS_EMUL & ~I2C_FUNC_SMBUS_QUICK);
421 }
422 
423 /* -----exported algorithm data: -------------------------------------	*/
424 
425 static const struct i2c_algorithm cpm_i2c_algo = {
426 	.master_xfer = cpm_i2c_xfer,
427 	.functionality = cpm_i2c_func,
428 };
429 
430 static const struct i2c_adapter cpm_ops = {
431 	.owner		= THIS_MODULE,
432 	.name		= "i2c-cpm",
433 	.algo		= &cpm_i2c_algo,
434 };
435 
436 static int cpm_i2c_setup(struct cpm_i2c *cpm)
437 {
438 	struct platform_device *ofdev = cpm->ofdev;
439 	const u32 *data;
440 	int len, ret, i;
441 	void __iomem *i2c_base;
442 	cbd_t __iomem *tbdf;
443 	cbd_t __iomem *rbdf;
444 	unsigned char brg;
445 
446 	dev_dbg(&cpm->ofdev->dev, "cpm_i2c_setup()\n");
447 
448 	init_waitqueue_head(&cpm->i2c_wait);
449 
450 	cpm->irq = irq_of_parse_and_map(ofdev->dev.of_node, 0);
451 	if (!cpm->irq)
452 		return -EINVAL;
453 
454 	/* Install interrupt handler. */
455 	ret = request_irq(cpm->irq, cpm_i2c_interrupt, 0, "cpm_i2c",
456 			  &cpm->adap);
457 	if (ret)
458 		return ret;
459 
460 	/* I2C parameter RAM */
461 	i2c_base = of_iomap(ofdev->dev.of_node, 1);
462 	if (i2c_base == NULL) {
463 		ret = -EINVAL;
464 		goto out_irq;
465 	}
466 
467 	if (of_device_is_compatible(ofdev->dev.of_node, "fsl,cpm1-i2c")) {
468 
469 		/* Check for and use a microcode relocation patch. */
470 		cpm->i2c_ram = i2c_base;
471 		cpm->i2c_addr = in_be16(&cpm->i2c_ram->rpbase);
472 
473 		/*
474 		 * Maybe should use cpm_muram_alloc instead of hardcoding
475 		 * this in micropatch.c
476 		 */
477 		if (cpm->i2c_addr) {
478 			cpm->i2c_ram = cpm_muram_addr(cpm->i2c_addr);
479 			iounmap(i2c_base);
480 		}
481 
482 		cpm->version = 1;
483 
484 	} else if (of_device_is_compatible(ofdev->dev.of_node, "fsl,cpm2-i2c")) {
485 		cpm->i2c_addr = cpm_muram_alloc(sizeof(struct i2c_ram), 64);
486 		cpm->i2c_ram = cpm_muram_addr(cpm->i2c_addr);
487 		out_be16(i2c_base, cpm->i2c_addr);
488 		iounmap(i2c_base);
489 
490 		cpm->version = 2;
491 
492 	} else {
493 		iounmap(i2c_base);
494 		ret = -EINVAL;
495 		goto out_irq;
496 	}
497 
498 	/* I2C control/status registers */
499 	cpm->i2c_reg = of_iomap(ofdev->dev.of_node, 0);
500 	if (cpm->i2c_reg == NULL) {
501 		ret = -EINVAL;
502 		goto out_ram;
503 	}
504 
505 	data = of_get_property(ofdev->dev.of_node, "fsl,cpm-command", &len);
506 	if (!data || len != 4) {
507 		ret = -EINVAL;
508 		goto out_reg;
509 	}
510 	cpm->cp_command = *data;
511 
512 	data = of_get_property(ofdev->dev.of_node, "linux,i2c-class", &len);
513 	if (data && len == 4)
514 		cpm->adap.class = *data;
515 
516 	data = of_get_property(ofdev->dev.of_node, "clock-frequency", &len);
517 	if (data && len == 4)
518 		cpm->freq = *data;
519 	else
520 		cpm->freq = 60000; /* use 60kHz i2c clock by default */
521 
522 	/*
523 	 * Allocate space for CPM_MAXBD transmit and receive buffer
524 	 * descriptors in the DP ram.
525 	 */
526 	cpm->dp_addr = cpm_muram_alloc(sizeof(cbd_t) * 2 * CPM_MAXBD, 8);
527 	if (!cpm->dp_addr) {
528 		ret = -ENOMEM;
529 		goto out_reg;
530 	}
531 
532 	cpm->tbase = cpm_muram_addr(cpm->dp_addr);
533 	cpm->rbase = cpm_muram_addr(cpm->dp_addr + sizeof(cbd_t) * CPM_MAXBD);
534 
535 	/* Allocate TX and RX buffers */
536 
537 	tbdf = cpm->tbase;
538 	rbdf = cpm->rbase;
539 
540 	for (i = 0; i < CPM_MAXBD; i++) {
541 		cpm->rxbuf[i] = dma_alloc_coherent(&cpm->ofdev->dev,
542 						   CPM_MAX_READ + 1,
543 						   &cpm->rxdma[i], GFP_KERNEL);
544 		if (!cpm->rxbuf[i]) {
545 			ret = -ENOMEM;
546 			goto out_muram;
547 		}
548 		out_be32(&rbdf[i].cbd_bufaddr, ((cpm->rxdma[i] + 1) & ~1));
549 
550 		cpm->txbuf[i] = (unsigned char *)dma_alloc_coherent(&cpm->ofdev->dev, CPM_MAX_READ + 1, &cpm->txdma[i], GFP_KERNEL);
551 		if (!cpm->txbuf[i]) {
552 			ret = -ENOMEM;
553 			goto out_muram;
554 		}
555 		out_be32(&tbdf[i].cbd_bufaddr, cpm->txdma[i]);
556 	}
557 
558 	/* Initialize Tx/Rx parameters. */
559 
560 	cpm_reset_i2c_params(cpm);
561 
562 	dev_dbg(&cpm->ofdev->dev, "i2c_ram 0x%p, i2c_addr 0x%04x, freq %d\n",
563 		cpm->i2c_ram, cpm->i2c_addr, cpm->freq);
564 	dev_dbg(&cpm->ofdev->dev, "tbase 0x%04x, rbase 0x%04x\n",
565 		(u8 __iomem *)cpm->tbase - DPRAM_BASE,
566 		(u8 __iomem *)cpm->rbase - DPRAM_BASE);
567 
568 	cpm_command(cpm->cp_command, CPM_CR_INIT_TRX);
569 
570 	/*
571 	 * Select an invalid address. Just make sure we don't use loopback mode
572 	 */
573 	out_8(&cpm->i2c_reg->i2add, 0x7f << 1);
574 
575 	/*
576 	 * PDIV is set to 00 in i2mod, so brgclk/32 is used as input to the
577 	 * i2c baud rate generator. This is divided by 2 x (DIV + 3) to get
578 	 * the actual i2c bus frequency.
579 	 */
580 	brg = get_brgfreq() / (32 * 2 * cpm->freq) - 3;
581 	out_8(&cpm->i2c_reg->i2brg, brg);
582 
583 	out_8(&cpm->i2c_reg->i2mod, 0x00);
584 	out_8(&cpm->i2c_reg->i2com, I2COM_MASTER);	/* Master mode */
585 
586 	/* Disable interrupts. */
587 	out_8(&cpm->i2c_reg->i2cmr, 0);
588 	out_8(&cpm->i2c_reg->i2cer, 0xff);
589 
590 	return 0;
591 
592 out_muram:
593 	for (i = 0; i < CPM_MAXBD; i++) {
594 		if (cpm->rxbuf[i])
595 			dma_free_coherent(&cpm->ofdev->dev, CPM_MAX_READ + 1,
596 				cpm->rxbuf[i], cpm->rxdma[i]);
597 		if (cpm->txbuf[i])
598 			dma_free_coherent(&cpm->ofdev->dev, CPM_MAX_READ + 1,
599 				cpm->txbuf[i], cpm->txdma[i]);
600 	}
601 	cpm_muram_free(cpm->dp_addr);
602 out_reg:
603 	iounmap(cpm->i2c_reg);
604 out_ram:
605 	if ((cpm->version == 1) && (!cpm->i2c_addr))
606 		iounmap(cpm->i2c_ram);
607 	if (cpm->version == 2)
608 		cpm_muram_free(cpm->i2c_addr);
609 out_irq:
610 	free_irq(cpm->irq, &cpm->adap);
611 	return ret;
612 }
613 
614 static void cpm_i2c_shutdown(struct cpm_i2c *cpm)
615 {
616 	int i;
617 
618 	/* Shut down I2C. */
619 	clrbits8(&cpm->i2c_reg->i2mod, I2MOD_EN);
620 
621 	/* Disable interrupts */
622 	out_8(&cpm->i2c_reg->i2cmr, 0);
623 	out_8(&cpm->i2c_reg->i2cer, 0xff);
624 
625 	free_irq(cpm->irq, &cpm->adap);
626 
627 	/* Free all memory */
628 	for (i = 0; i < CPM_MAXBD; i++) {
629 		dma_free_coherent(&cpm->ofdev->dev, CPM_MAX_READ + 1,
630 			cpm->rxbuf[i], cpm->rxdma[i]);
631 		dma_free_coherent(&cpm->ofdev->dev, CPM_MAX_READ + 1,
632 			cpm->txbuf[i], cpm->txdma[i]);
633 	}
634 
635 	cpm_muram_free(cpm->dp_addr);
636 	iounmap(cpm->i2c_reg);
637 
638 	if ((cpm->version == 1) && (!cpm->i2c_addr))
639 		iounmap(cpm->i2c_ram);
640 	if (cpm->version == 2)
641 		cpm_muram_free(cpm->i2c_addr);
642 }
643 
644 static int cpm_i2c_probe(struct platform_device *ofdev)
645 {
646 	int result, len;
647 	struct cpm_i2c *cpm;
648 	const u32 *data;
649 
650 	cpm = kzalloc(sizeof(struct cpm_i2c), GFP_KERNEL);
651 	if (!cpm)
652 		return -ENOMEM;
653 
654 	cpm->ofdev = ofdev;
655 
656 	platform_set_drvdata(ofdev, cpm);
657 
658 	cpm->adap = cpm_ops;
659 	i2c_set_adapdata(&cpm->adap, cpm);
660 	cpm->adap.dev.parent = &ofdev->dev;
661 	cpm->adap.dev.of_node = of_node_get(ofdev->dev.of_node);
662 
663 	result = cpm_i2c_setup(cpm);
664 	if (result) {
665 		dev_err(&ofdev->dev, "Unable to init hardware\n");
666 		goto out_free;
667 	}
668 
669 	/* register new adapter to i2c module... */
670 
671 	data = of_get_property(ofdev->dev.of_node, "linux,i2c-index", &len);
672 	cpm->adap.nr = (data && len == 4) ? be32_to_cpup(data) : -1;
673 	result = i2c_add_numbered_adapter(&cpm->adap);
674 
675 	if (result < 0) {
676 		dev_err(&ofdev->dev, "Unable to register with I2C\n");
677 		goto out_shut;
678 	}
679 
680 	dev_dbg(&ofdev->dev, "hw routines for %s registered.\n",
681 		cpm->adap.name);
682 
683 	return 0;
684 out_shut:
685 	cpm_i2c_shutdown(cpm);
686 out_free:
687 	kfree(cpm);
688 
689 	return result;
690 }
691 
692 static int cpm_i2c_remove(struct platform_device *ofdev)
693 {
694 	struct cpm_i2c *cpm = platform_get_drvdata(ofdev);
695 
696 	i2c_del_adapter(&cpm->adap);
697 
698 	cpm_i2c_shutdown(cpm);
699 
700 	kfree(cpm);
701 
702 	return 0;
703 }
704 
705 static const struct of_device_id cpm_i2c_match[] = {
706 	{
707 		.compatible = "fsl,cpm1-i2c",
708 	},
709 	{
710 		.compatible = "fsl,cpm2-i2c",
711 	},
712 	{},
713 };
714 
715 MODULE_DEVICE_TABLE(of, cpm_i2c_match);
716 
717 static struct platform_driver cpm_i2c_driver = {
718 	.probe		= cpm_i2c_probe,
719 	.remove		= cpm_i2c_remove,
720 	.driver = {
721 		.name = "fsl-i2c-cpm",
722 		.owner = THIS_MODULE,
723 		.of_match_table = cpm_i2c_match,
724 	},
725 };
726 
727 module_platform_driver(cpm_i2c_driver);
728 
729 MODULE_AUTHOR("Jochen Friedrich <jochen@scram.de>");
730 MODULE_DESCRIPTION("I2C-Bus adapter routines for CPM boards");
731 MODULE_LICENSE("GPL");
732