xref: /openbmc/u-boot/drivers/i2c/fsl_i2c.c (revision 4f67b93f)
1 /*
2  * Copyright 2006,2009 Freescale Semiconductor, Inc.
3  *
4  * 2012, Heiko Schocher, DENX Software Engineering, hs@denx.de.
5  * Changes for multibus/multiadapter I2C support.
6  *
7  * SPDX-License-Identifier:	GPL-2.0
8  */
9 
10 #include <common.h>
11 #include <command.h>
12 #include <i2c.h>		/* Functional interface */
13 #include <asm/io.h>
14 #include <asm/fsl_i2c.h>	/* HW definitions */
15 #include <clk.h>
16 #include <dm.h>
17 #include <mapmem.h>
18 
19 /* The maximum number of microseconds we will wait until another master has
20  * released the bus.  If not defined in the board header file, then use a
21  * generic value.
22  */
23 #ifndef CONFIG_I2C_MBB_TIMEOUT
24 #define CONFIG_I2C_MBB_TIMEOUT	100000
25 #endif
26 
27 /* The maximum number of microseconds we will wait for a read or write
28  * operation to complete.  If not defined in the board header file, then use a
29  * generic value.
30  */
31 #ifndef CONFIG_I2C_TIMEOUT
32 #define CONFIG_I2C_TIMEOUT	100000
33 #endif
34 
35 #define I2C_READ_BIT  1
36 #define I2C_WRITE_BIT 0
37 
38 DECLARE_GLOBAL_DATA_PTR;
39 
40 #ifndef CONFIG_DM_I2C
41 static const struct fsl_i2c_base *i2c_base[4] = {
42 	(struct fsl_i2c_base *)(CONFIG_SYS_IMMR + CONFIG_SYS_FSL_I2C_OFFSET),
43 #ifdef CONFIG_SYS_FSL_I2C2_OFFSET
44 	(struct fsl_i2c_base *)(CONFIG_SYS_IMMR + CONFIG_SYS_FSL_I2C2_OFFSET),
45 #endif
46 #ifdef CONFIG_SYS_FSL_I2C3_OFFSET
47 	(struct fsl_i2c_base *)(CONFIG_SYS_IMMR + CONFIG_SYS_FSL_I2C3_OFFSET),
48 #endif
49 #ifdef CONFIG_SYS_FSL_I2C4_OFFSET
50 	(struct fsl_i2c_base *)(CONFIG_SYS_IMMR + CONFIG_SYS_FSL_I2C4_OFFSET)
51 #endif
52 };
53 #endif
54 
55 /* I2C speed map for a DFSR value of 1 */
56 
57 #ifdef __M68K__
58 /*
59  * Map I2C frequency dividers to FDR and DFSR values
60  *
61  * This structure is used to define the elements of a table that maps I2C
62  * frequency divider (I2C clock rate divided by I2C bus speed) to a value to be
63  * programmed into the Frequency Divider Ratio (FDR) and Digital Filter
64  * Sampling Rate (DFSR) registers.
65  *
66  * The actual table should be defined in the board file, and it must be called
67  * fsl_i2c_speed_map[].
68  *
69  * The last entry of the table must have a value of {-1, X}, where X is same
70  * FDR/DFSR values as the second-to-last entry.  This guarantees that any
71  * search through the array will always find a match.
72  *
73  * The values of the divider must be in increasing numerical order, i.e.
74  * fsl_i2c_speed_map[x+1].divider > fsl_i2c_speed_map[x].divider.
75  *
76  * For this table, the values are based on a value of 1 for the DFSR
77  * register.  See the application note AN2919 "Determining the I2C Frequency
78  * Divider Ratio for SCL"
79  *
80  * ColdFire I2C frequency dividers for FDR values are different from
81  * PowerPC. The protocol to use the I2C module is still the same.
82  * A different table is defined and are based on MCF5xxx user manual.
83  *
84  */
85 static const struct {
86 	unsigned short divider;
87 	u8 fdr;
88 } fsl_i2c_speed_map[] = {
89 	{20, 32}, {22, 33}, {24, 34}, {26, 35},
90 	{28, 0}, {28, 36}, {30, 1}, {32, 37},
91 	{34, 2}, {36, 38}, {40, 3}, {40, 39},
92 	{44, 4}, {48, 5}, {48, 40}, {56, 6},
93 	{56, 41}, {64, 42}, {68, 7}, {72, 43},
94 	{80, 8}, {80, 44}, {88, 9}, {96, 41},
95 	{104, 10}, {112, 42}, {128, 11}, {128, 43},
96 	{144, 12}, {160, 13}, {160, 48}, {192, 14},
97 	{192, 49}, {224, 50}, {240, 15}, {256, 51},
98 	{288, 16}, {320, 17}, {320, 52}, {384, 18},
99 	{384, 53}, {448, 54}, {480, 19}, {512, 55},
100 	{576, 20}, {640, 21}, {640, 56}, {768, 22},
101 	{768, 57}, {960, 23}, {896, 58}, {1024, 59},
102 	{1152, 24}, {1280, 25}, {1280, 60}, {1536, 26},
103 	{1536, 61}, {1792, 62}, {1920, 27}, {2048, 63},
104 	{2304, 28}, {2560, 29}, {3072, 30}, {3840, 31},
105 	{-1, 31}
106 };
107 #endif
108 
109 /**
110  * Set the I2C bus speed for a given I2C device
111  *
112  * @param base: the I2C device registers
113  * @i2c_clk: I2C bus clock frequency
114  * @speed: the desired speed of the bus
115  *
116  * The I2C device must be stopped before calling this function.
117  *
118  * The return value is the actual bus speed that is set.
119  */
120 static uint set_i2c_bus_speed(const struct fsl_i2c_base *base,
121 			      uint i2c_clk, uint speed)
122 {
123 	ushort divider = min(i2c_clk / speed, (uint)USHRT_MAX);
124 
125 	/*
126 	 * We want to choose an FDR/DFSR that generates an I2C bus speed that
127 	 * is equal to or lower than the requested speed.  That means that we
128 	 * want the first divider that is equal to or greater than the
129 	 * calculated divider.
130 	 */
131 #ifdef __PPC__
132 	u8 dfsr, fdr = 0x31; /* Default if no FDR found */
133 	/* a, b and dfsr matches identifiers A,B and C respectively in AN2919 */
134 	ushort a, b, ga, gb;
135 	ulong c_div, est_div;
136 
137 #ifdef CONFIG_FSL_I2C_CUSTOM_DFSR
138 	dfsr = CONFIG_FSL_I2C_CUSTOM_DFSR;
139 #else
140 	/* Condition 1: dfsr <= 50/T */
141 	dfsr = (5 * (i2c_clk / 1000)) / 100000;
142 #endif
143 #ifdef CONFIG_FSL_I2C_CUSTOM_FDR
144 	fdr = CONFIG_FSL_I2C_CUSTOM_FDR;
145 	speed = i2c_clk / divider; /* Fake something */
146 #else
147 	debug("Requested speed:%d, i2c_clk:%d\n", speed, i2c_clk);
148 	if (!dfsr)
149 		dfsr = 1;
150 
151 	est_div = ~0;
152 	for (ga = 0x4, a = 10; a <= 30; ga++, a += 2) {
153 		for (gb = 0; gb < 8; gb++) {
154 			b = 16 << gb;
155 			c_div = b * (a + ((3 * dfsr) / b) * 2);
156 			if (c_div > divider && c_div < est_div) {
157 				ushort bin_gb, bin_ga;
158 
159 				est_div = c_div;
160 				bin_gb = gb << 2;
161 				bin_ga = (ga & 0x3) | ((ga & 0x4) << 3);
162 				fdr = bin_gb | bin_ga;
163 				speed = i2c_clk / est_div;
164 
165 				debug("FDR: 0x%.2x, ", fdr);
166 				debug("div: %ld, ", est_div);
167 				debug("ga: 0x%x, gb: 0x%x, ", ga, gb);
168 				debug("a: %d, b: %d, speed: %d\n", a, b, speed);
169 
170 				/* Condition 2 not accounted for */
171 				debug("Tr <= %d ns\n",
172 				      (b - 3 * dfsr) * 1000000 /
173 				      (i2c_clk / 1000));
174 			}
175 		}
176 		if (a == 20)
177 			a += 2;
178 		if (a == 24)
179 			a += 4;
180 	}
181 	debug("divider: %d, est_div: %ld, DFSR: %d\n", divider, est_div, dfsr);
182 	debug("FDR: 0x%.2x, speed: %d\n", fdr, speed);
183 #endif
184 	writeb(dfsr, &base->dfsrr);	/* set default filter */
185 	writeb(fdr, &base->fdr);	/* set bus speed */
186 #else
187 	uint i;
188 
189 	for (i = 0; i < ARRAY_SIZE(fsl_i2c_speed_map); i++)
190 		if (fsl_i2c_speed_map[i].divider >= divider) {
191 			u8 fdr;
192 
193 			fdr = fsl_i2c_speed_map[i].fdr;
194 			speed = i2c_clk / fsl_i2c_speed_map[i].divider;
195 			writeb(fdr, &base->fdr);	/* set bus speed */
196 
197 			break;
198 		}
199 #endif
200 	return speed;
201 }
202 
203 #ifndef CONFIG_DM_I2C
204 static uint get_i2c_clock(int bus)
205 {
206 	if (bus)
207 		return gd->arch.i2c2_clk;	/* I2C2 clock */
208 	else
209 		return gd->arch.i2c1_clk;	/* I2C1 clock */
210 }
211 #endif
212 
213 static int fsl_i2c_fixup(const struct fsl_i2c_base *base)
214 {
215 	const unsigned long long timeout = usec2ticks(CONFIG_I2C_MBB_TIMEOUT);
216 	unsigned long long timeval = 0;
217 	int ret = -1;
218 	uint flags = 0;
219 
220 #ifdef CONFIG_SYS_FSL_ERRATUM_I2C_A004447
221 	uint svr = get_svr();
222 
223 	if ((SVR_SOC_VER(svr) == SVR_8548 && IS_SVR_REV(svr, 3, 1)) ||
224 	    (SVR_REV(svr) <= CONFIG_SYS_FSL_A004447_SVR_REV))
225 		flags = I2C_CR_BIT6;
226 #endif
227 
228 	writeb(I2C_CR_MEN | I2C_CR_MSTA, &base->cr);
229 
230 	timeval = get_ticks();
231 	while (!(readb(&base->sr) & I2C_SR_MBB)) {
232 		if ((get_ticks() - timeval) > timeout)
233 			goto err;
234 	}
235 
236 	if (readb(&base->sr) & I2C_SR_MAL) {
237 		/* SDA is stuck low */
238 		writeb(0, &base->cr);
239 		udelay(100);
240 		writeb(I2C_CR_MSTA | flags, &base->cr);
241 		writeb(I2C_CR_MEN | I2C_CR_MSTA | flags, &base->cr);
242 	}
243 
244 	readb(&base->dr);
245 
246 	timeval = get_ticks();
247 	while (!(readb(&base->sr) & I2C_SR_MIF)) {
248 		if ((get_ticks() - timeval) > timeout)
249 			goto err;
250 	}
251 	ret = 0;
252 
253 err:
254 	writeb(I2C_CR_MEN | flags, &base->cr);
255 	writeb(0, &base->sr);
256 	udelay(100);
257 
258 	return ret;
259 }
260 
261 static void __i2c_init(const struct fsl_i2c_base *base, int speed, int
262 		       slaveadd, int i2c_clk, int busnum)
263 {
264 	const unsigned long long timeout = usec2ticks(CONFIG_I2C_MBB_TIMEOUT);
265 	unsigned long long timeval;
266 
267 #ifdef CONFIG_SYS_I2C_INIT_BOARD
268 	/* Call board specific i2c bus reset routine before accessing the
269 	 * environment, which might be in a chip on that bus. For details
270 	 * about this problem see doc/I2C_Edge_Conditions.
271 	 */
272 	i2c_init_board();
273 #endif
274 	writeb(0, &base->cr);		/* stop I2C controller */
275 	udelay(5);			/* let it shutdown in peace */
276 	set_i2c_bus_speed(base, i2c_clk, speed);
277 	writeb(slaveadd << 1, &base->adr);/* write slave address */
278 	writeb(0x0, &base->sr);		/* clear status register */
279 	writeb(I2C_CR_MEN, &base->cr);	/* start I2C controller */
280 
281 	timeval = get_ticks();
282 	while (readb(&base->sr) & I2C_SR_MBB) {
283 		if ((get_ticks() - timeval) < timeout)
284 			continue;
285 
286 		if (fsl_i2c_fixup(base))
287 			debug("i2c_init: BUS#%d failed to init\n",
288 			      busnum);
289 
290 		break;
291 	}
292 }
293 
294 static int i2c_wait4bus(const struct fsl_i2c_base *base)
295 {
296 	unsigned long long timeval = get_ticks();
297 	const unsigned long long timeout = usec2ticks(CONFIG_I2C_MBB_TIMEOUT);
298 
299 	while (readb(&base->sr) & I2C_SR_MBB) {
300 		if ((get_ticks() - timeval) > timeout)
301 			return -1;
302 	}
303 
304 	return 0;
305 }
306 
307 static int i2c_wait(const struct fsl_i2c_base *base, int write)
308 {
309 	u32 csr;
310 	unsigned long long timeval = get_ticks();
311 	const unsigned long long timeout = usec2ticks(CONFIG_I2C_TIMEOUT);
312 
313 	do {
314 		csr = readb(&base->sr);
315 		if (!(csr & I2C_SR_MIF))
316 			continue;
317 		/* Read again to allow register to stabilise */
318 		csr = readb(&base->sr);
319 
320 		writeb(0x0, &base->sr);
321 
322 		if (csr & I2C_SR_MAL) {
323 			debug("%s: MAL\n", __func__);
324 			return -1;
325 		}
326 
327 		if (!(csr & I2C_SR_MCF))	{
328 			debug("%s: unfinished\n", __func__);
329 			return -1;
330 		}
331 
332 		if (write == I2C_WRITE_BIT && (csr & I2C_SR_RXAK)) {
333 			debug("%s: No RXACK\n", __func__);
334 			return -1;
335 		}
336 
337 		return 0;
338 	} while ((get_ticks() - timeval) < timeout);
339 
340 	debug("%s: timed out\n", __func__);
341 	return -1;
342 }
343 
344 static int i2c_write_addr(const struct fsl_i2c_base *base, u8 dev,
345 			  u8 dir, int rsta)
346 {
347 	writeb(I2C_CR_MEN | I2C_CR_MSTA | I2C_CR_MTX
348 	       | (rsta ? I2C_CR_RSTA : 0),
349 	       &base->cr);
350 
351 	writeb((dev << 1) | dir, &base->dr);
352 
353 	if (i2c_wait(base, I2C_WRITE_BIT) < 0)
354 		return 0;
355 
356 	return 1;
357 }
358 
359 static int __i2c_write_data(const struct fsl_i2c_base *base, u8 *data,
360 			    int length)
361 {
362 	int i;
363 
364 	for (i = 0; i < length; i++) {
365 		writeb(data[i], &base->dr);
366 
367 		if (i2c_wait(base, I2C_WRITE_BIT) < 0)
368 			break;
369 	}
370 
371 	return i;
372 }
373 
374 static int __i2c_read_data(const struct fsl_i2c_base *base, u8 *data,
375 			   int length)
376 {
377 	int i;
378 
379 	writeb(I2C_CR_MEN | I2C_CR_MSTA | ((length == 1) ? I2C_CR_TXAK : 0),
380 	       &base->cr);
381 
382 	/* dummy read */
383 	readb(&base->dr);
384 
385 	for (i = 0; i < length; i++) {
386 		if (i2c_wait(base, I2C_READ_BIT) < 0)
387 			break;
388 
389 		/* Generate ack on last next to last byte */
390 		if (i == length - 2)
391 			writeb(I2C_CR_MEN | I2C_CR_MSTA | I2C_CR_TXAK,
392 			       &base->cr);
393 
394 		/* Do not generate stop on last byte */
395 		if (i == length - 1)
396 			writeb(I2C_CR_MEN | I2C_CR_MSTA | I2C_CR_MTX,
397 			       &base->cr);
398 
399 		data[i] = readb(&base->dr);
400 	}
401 
402 	return i;
403 }
404 
405 static int __i2c_read(const struct fsl_i2c_base *base, u8 chip_addr, u8 *offset,
406 		      int olen, u8 *data, int dlen)
407 {
408 	int ret = -1; /* signal error */
409 
410 	if (i2c_wait4bus(base) < 0)
411 		return -1;
412 
413 	/* Some drivers use offset lengths in excess of 4 bytes. These drivers
414 	 * adhere to the following convention:
415 	 * - the offset length is passed as negative (that is, the absolute
416 	 *   value of olen is the actual offset length)
417 	 * - the offset itself is passed in data, which is overwritten by the
418 	 *   subsequent read operation
419 	 */
420 	if (olen < 0) {
421 		if (i2c_write_addr(base, chip_addr, I2C_WRITE_BIT, 0) != 0)
422 			ret = __i2c_write_data(base, data, -olen);
423 
424 		if (ret != -olen)
425 			return -1;
426 
427 		if (dlen && i2c_write_addr(base, chip_addr,
428 					   I2C_READ_BIT, 1) != 0)
429 			ret = __i2c_read_data(base, data, dlen);
430 	} else {
431 		if ((!dlen || olen > 0) &&
432 		    i2c_write_addr(base, chip_addr, I2C_WRITE_BIT, 0) != 0  &&
433 		    __i2c_write_data(base, offset, olen) == olen)
434 			ret = 0; /* No error so far */
435 
436 		if (dlen && i2c_write_addr(base, chip_addr, I2C_READ_BIT,
437 					   olen ? 1 : 0) != 0)
438 			ret = __i2c_read_data(base, data, dlen);
439 	}
440 
441 	writeb(I2C_CR_MEN, &base->cr);
442 
443 	if (i2c_wait4bus(base)) /* Wait until STOP */
444 		debug("i2c_read: wait4bus timed out\n");
445 
446 	if (ret == dlen)
447 		return 0;
448 
449 	return -1;
450 }
451 
452 static int __i2c_write(const struct fsl_i2c_base *base, u8 chip_addr,
453 		       u8 *offset, int olen, u8 *data, int dlen)
454 {
455 	int ret = -1; /* signal error */
456 
457 	if (i2c_wait4bus(base) < 0)
458 		return -1;
459 
460 	if (i2c_write_addr(base, chip_addr, I2C_WRITE_BIT, 0) != 0 &&
461 	    __i2c_write_data(base, offset, olen) == olen) {
462 		ret = __i2c_write_data(base, data, dlen);
463 	}
464 
465 	writeb(I2C_CR_MEN, &base->cr);
466 	if (i2c_wait4bus(base)) /* Wait until STOP */
467 		debug("i2c_write: wait4bus timed out\n");
468 
469 	if (ret == dlen)
470 		return 0;
471 
472 	return -1;
473 }
474 
475 static int __i2c_probe_chip(const struct fsl_i2c_base *base, uchar chip)
476 {
477 	/* For unknown reason the controller will ACK when
478 	 * probing for a slave with the same address, so skip
479 	 * it.
480 	 */
481 	if (chip == (readb(&base->adr) >> 1))
482 		return -1;
483 
484 	return __i2c_read(base, chip, 0, 0, NULL, 0);
485 }
486 
487 static uint __i2c_set_bus_speed(const struct fsl_i2c_base *base,
488 				uint speed, int i2c_clk)
489 {
490 	writeb(0, &base->cr);		/* stop controller */
491 	set_i2c_bus_speed(base, i2c_clk, speed);
492 	writeb(I2C_CR_MEN, &base->cr);	/* start controller */
493 
494 	return 0;
495 }
496 
497 #ifndef CONFIG_DM_I2C
498 static void fsl_i2c_init(struct i2c_adapter *adap, int speed, int slaveadd)
499 {
500 	__i2c_init(i2c_base[adap->hwadapnr], speed, slaveadd,
501 		   get_i2c_clock(adap->hwadapnr), adap->hwadapnr);
502 }
503 
504 static int fsl_i2c_probe_chip(struct i2c_adapter *adap, uchar chip)
505 {
506 	return __i2c_probe_chip(i2c_base[adap->hwadapnr], chip);
507 }
508 
509 static int fsl_i2c_read(struct i2c_adapter *adap, u8 chip_addr, uint offset,
510 			int olen, u8 *data, int dlen)
511 {
512 	u8 *o = (u8 *)&offset;
513 
514 	return __i2c_read(i2c_base[adap->hwadapnr], chip_addr, &o[4 - olen],
515 			  olen, data, dlen);
516 }
517 
518 static int fsl_i2c_write(struct i2c_adapter *adap, u8 chip_addr, uint offset,
519 			 int olen, u8 *data, int dlen)
520 {
521 	u8 *o = (u8 *)&offset;
522 
523 	return __i2c_write(i2c_base[adap->hwadapnr], chip_addr, &o[4 - olen],
524 			   olen, data, dlen);
525 }
526 
527 static uint fsl_i2c_set_bus_speed(struct i2c_adapter *adap, uint speed)
528 {
529 	return __i2c_set_bus_speed(i2c_base[adap->hwadapnr], speed,
530 				   get_i2c_clock(adap->hwadapnr));
531 }
532 
533 /*
534  * Register fsl i2c adapters
535  */
536 U_BOOT_I2C_ADAP_COMPLETE(fsl_0, fsl_i2c_init, fsl_i2c_probe_chip, fsl_i2c_read,
537 			 fsl_i2c_write, fsl_i2c_set_bus_speed,
538 			 CONFIG_SYS_FSL_I2C_SPEED, CONFIG_SYS_FSL_I2C_SLAVE,
539 			 0)
540 #ifdef CONFIG_SYS_FSL_I2C2_OFFSET
541 U_BOOT_I2C_ADAP_COMPLETE(fsl_1, fsl_i2c_init, fsl_i2c_probe_chip, fsl_i2c_read,
542 			 fsl_i2c_write, fsl_i2c_set_bus_speed,
543 			 CONFIG_SYS_FSL_I2C2_SPEED, CONFIG_SYS_FSL_I2C2_SLAVE,
544 			 1)
545 #endif
546 #ifdef CONFIG_SYS_FSL_I2C3_OFFSET
547 U_BOOT_I2C_ADAP_COMPLETE(fsl_2, fsl_i2c_init, fsl_i2c_probe_chip, fsl_i2c_read,
548 			 fsl_i2c_write, fsl_i2c_set_bus_speed,
549 			 CONFIG_SYS_FSL_I2C3_SPEED, CONFIG_SYS_FSL_I2C3_SLAVE,
550 			 2)
551 #endif
552 #ifdef CONFIG_SYS_FSL_I2C4_OFFSET
553 U_BOOT_I2C_ADAP_COMPLETE(fsl_3, fsl_i2c_init, fsl_i2c_probe_chip, fsl_i2c_read,
554 			 fsl_i2c_write, fsl_i2c_set_bus_speed,
555 			 CONFIG_SYS_FSL_I2C4_SPEED, CONFIG_SYS_FSL_I2C4_SLAVE,
556 			 3)
557 #endif
558 #else /* CONFIG_DM_I2C */
559 static int fsl_i2c_probe_chip(struct udevice *bus, u32 chip_addr,
560 			      u32 chip_flags)
561 {
562 	struct fsl_i2c_dev *dev = dev_get_priv(bus);
563 
564 	return __i2c_probe_chip(dev->base, chip_addr);
565 }
566 
567 static int fsl_i2c_set_bus_speed(struct udevice *bus, uint speed)
568 {
569 	struct fsl_i2c_dev *dev = dev_get_priv(bus);
570 
571 	return __i2c_set_bus_speed(dev->base, speed, dev->i2c_clk);
572 }
573 
574 static int fsl_i2c_ofdata_to_platdata(struct udevice *bus)
575 {
576 	struct fsl_i2c_dev *dev = dev_get_priv(bus);
577 	struct clk clock;
578 
579 	dev->base = map_sysmem(dev_read_addr(bus), sizeof(struct fsl_i2c_base));
580 
581 	if (!dev->base)
582 		return -ENOMEM;
583 
584 	dev->index = dev_read_u32_default(bus, "cell-index", -1);
585 	dev->slaveadd = dev_read_u32_default(bus, "u-boot,i2c-slave-addr",
586 					     0x7f);
587 	dev->speed = dev_read_u32_default(bus, "clock-frequency", 400000);
588 
589 	if (!clk_get_by_index(bus, 0, &clock))
590 		dev->i2c_clk = clk_get_rate(&clock);
591 	else
592 		dev->i2c_clk = dev->index ? gd->arch.i2c2_clk :
593 					    gd->arch.i2c1_clk;
594 
595 	return 0;
596 }
597 
598 static int fsl_i2c_probe(struct udevice *bus)
599 {
600 	struct fsl_i2c_dev *dev = dev_get_priv(bus);
601 
602 	__i2c_init(dev->base, dev->speed, dev->slaveadd, dev->i2c_clk,
603 		   dev->index);
604 	return 0;
605 }
606 
607 static int fsl_i2c_xfer(struct udevice *bus, struct i2c_msg *msg, int nmsgs)
608 {
609 	struct fsl_i2c_dev *dev = dev_get_priv(bus);
610 	struct i2c_msg *dmsg, *omsg, dummy;
611 
612 	memset(&dummy, 0, sizeof(struct i2c_msg));
613 
614 	/* We expect either two messages (one with an offset and one with the
615 	 * actual data) or one message (just data)
616 	 */
617 	if (nmsgs > 2 || nmsgs == 0) {
618 		debug("%s: Only one or two messages are supported.", __func__);
619 		return -1;
620 	}
621 
622 	omsg = nmsgs == 1 ? &dummy : msg;
623 	dmsg = nmsgs == 1 ? msg : msg + 1;
624 
625 	if (dmsg->flags & I2C_M_RD)
626 		return __i2c_read(dev->base, dmsg->addr, omsg->buf, omsg->len,
627 				  dmsg->buf, dmsg->len);
628 	else
629 		return __i2c_write(dev->base, dmsg->addr, omsg->buf, omsg->len,
630 				   dmsg->buf, dmsg->len);
631 }
632 
633 static const struct dm_i2c_ops fsl_i2c_ops = {
634 	.xfer           = fsl_i2c_xfer,
635 	.probe_chip     = fsl_i2c_probe_chip,
636 	.set_bus_speed  = fsl_i2c_set_bus_speed,
637 };
638 
639 static const struct udevice_id fsl_i2c_ids[] = {
640 	{ .compatible = "fsl-i2c", },
641 	{ /* sentinel */ }
642 };
643 
644 U_BOOT_DRIVER(i2c_fsl) = {
645 	.name = "i2c_fsl",
646 	.id = UCLASS_I2C,
647 	.of_match = fsl_i2c_ids,
648 	.probe = fsl_i2c_probe,
649 	.ofdata_to_platdata = fsl_i2c_ofdata_to_platdata,
650 	.priv_auto_alloc_size = sizeof(struct fsl_i2c_dev),
651 	.ops = &fsl_i2c_ops,
652 };
653 
654 #endif /* CONFIG_DM_I2C */
655