xref: /openbmc/u-boot/drivers/i2c/omap24xx_i2c.c (revision 8ee59472)
1 /*
2  * Basic I2C functions
3  *
4  * Copyright (c) 2004 Texas Instruments
5  *
6  * This package is free software;  you can redistribute it and/or
7  * modify it under the terms of the license found in the file
8  * named COPYING that should have accompanied this file.
9  *
10  * THIS PACKAGE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
11  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
12  * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
13  *
14  * Author: Jian Zhang jzhang@ti.com, Texas Instruments
15  *
16  * Copyright (c) 2003 Wolfgang Denk, wd@denx.de
17  * Rewritten to fit into the current U-Boot framework
18  *
19  * Adapted for OMAP2420 I2C, r-woodruff2@ti.com
20  *
21  * Copyright (c) 2013 Lubomir Popov <lpopov@mm-sol.com>, MM Solutions
22  * New i2c_read, i2c_write and i2c_probe functions, tested on OMAP4
23  * (4430/60/70), OMAP5 (5430) and AM335X (3359); should work on older
24  * OMAPs and derivatives as well. The only anticipated exception would
25  * be the OMAP2420, which shall require driver modification.
26  * - Rewritten i2c_read to operate correctly with all types of chips
27  *   (old function could not read consistent data from some I2C slaves).
28  * - Optimized i2c_write.
29  * - New i2c_probe, performs write access vs read. The old probe could
30  *   hang the system under certain conditions (e.g. unconfigured pads).
31  * - The read/write/probe functions try to identify unconfigured bus.
32  * - Status functions now read irqstatus_raw as per TRM guidelines
33  *   (except for OMAP243X and OMAP34XX).
34  * - Driver now supports up to I2C5 (OMAP5).
35  *
36  * Copyright (c) 2014 Hannes Schmelzer <oe5hpm@oevsv.at>, B&R
37  * - Added support for set_speed
38  *
39  */
40 
41 #include <common.h>
42 #include <dm.h>
43 #include <i2c.h>
44 
45 #include <asm/arch/i2c.h>
46 #include <asm/io.h>
47 
48 #include "omap24xx_i2c.h"
49 
50 #define I2C_TIMEOUT	1000
51 
52 /* Absolutely safe for status update at 100 kHz I2C: */
53 #define I2C_WAIT	200
54 
55 struct omap_i2c {
56 	struct udevice *clk;
57 	struct i2c *regs;
58 	unsigned int speed;
59 	int waitdelay;
60 	int clk_id;
61 };
62 
63 static int omap24_i2c_findpsc(u32 *pscl, u32 *psch, uint speed)
64 {
65 	unsigned long internal_clk = 0, fclk;
66 	unsigned int prescaler;
67 
68 	/*
69 	 * This method is only called for Standard and Fast Mode speeds
70 	 *
71 	 * For some TI SoCs it is explicitly written in TRM (e,g, SPRUHZ6G,
72 	 * page 5685, Table 24-7)
73 	 * that the internal I2C clock (after prescaler) should be between
74 	 * 7-12 MHz (at least for Fast Mode (FS)).
75 	 *
76 	 * Such approach is used in v4.9 Linux kernel in:
77 	 * ./drivers/i2c/busses/i2c-omap.c (omap_i2c_init function).
78 	 */
79 
80 	speed /= 1000; /* convert speed to kHz */
81 
82 	if (speed > 100)
83 		internal_clk = 9600;
84 	else
85 		internal_clk = 4000;
86 
87 	fclk = I2C_IP_CLK / 1000;
88 	prescaler = fclk / internal_clk;
89 	prescaler = prescaler - 1;
90 
91 	if (speed > 100) {
92 		unsigned long scl;
93 
94 		/* Fast mode */
95 		scl = internal_clk / speed;
96 		*pscl = scl - (scl / 3) - I2C_FASTSPEED_SCLL_TRIM;
97 		*psch = (scl / 3) - I2C_FASTSPEED_SCLH_TRIM;
98 	} else {
99 		/* Standard mode */
100 		*pscl = internal_clk / (speed * 2) - I2C_FASTSPEED_SCLL_TRIM;
101 		*psch = internal_clk / (speed * 2) - I2C_FASTSPEED_SCLH_TRIM;
102 	}
103 
104 	debug("%s: speed [kHz]: %d psc: 0x%x sscl: 0x%x ssch: 0x%x\n",
105 	      __func__, speed, prescaler, *pscl, *psch);
106 
107 	if (*pscl <= 0 || *psch <= 0 || prescaler <= 0)
108 		return -EINVAL;
109 
110 	return prescaler;
111 }
112 
113 /*
114  * Wait for the bus to be free by checking the Bus Busy (BB)
115  * bit to become clear
116  */
117 static int wait_for_bb(struct i2c *i2c_base, int waitdelay)
118 {
119 	int timeout = I2C_TIMEOUT;
120 	u16 stat;
121 
122 	writew(0xFFFF, &i2c_base->stat);	/* clear current interrupts...*/
123 #if defined(CONFIG_OMAP34XX)
124 	while ((stat = readw(&i2c_base->stat) & I2C_STAT_BB) && timeout--) {
125 #else
126 	/* Read RAW status */
127 	while ((stat = readw(&i2c_base->irqstatus_raw) &
128 		I2C_STAT_BB) && timeout--) {
129 #endif
130 		writew(stat, &i2c_base->stat);
131 		udelay(waitdelay);
132 	}
133 
134 	if (timeout <= 0) {
135 		printf("Timed out in wait_for_bb: status=%04x\n",
136 		       stat);
137 		return 1;
138 	}
139 	writew(0xFFFF, &i2c_base->stat);	 /* clear delayed stuff*/
140 	return 0;
141 }
142 
143 /*
144  * Wait for the I2C controller to complete current action
145  * and update status
146  */
147 static u16 wait_for_event(struct i2c *i2c_base, int waitdelay)
148 {
149 	u16 status;
150 	int timeout = I2C_TIMEOUT;
151 
152 	do {
153 		udelay(waitdelay);
154 #if defined(CONFIG_OMAP34XX)
155 		status = readw(&i2c_base->stat);
156 #else
157 		/* Read RAW status */
158 		status = readw(&i2c_base->irqstatus_raw);
159 #endif
160 	} while (!(status &
161 		   (I2C_STAT_ROVR | I2C_STAT_XUDF | I2C_STAT_XRDY |
162 		    I2C_STAT_RRDY | I2C_STAT_ARDY | I2C_STAT_NACK |
163 		    I2C_STAT_AL)) && timeout--);
164 
165 	if (timeout <= 0) {
166 		printf("Timed out in wait_for_event: status=%04x\n",
167 		       status);
168 		/*
169 		 * If status is still 0 here, probably the bus pads have
170 		 * not been configured for I2C, and/or pull-ups are missing.
171 		 */
172 		printf("Check if pads/pull-ups of bus are properly configured\n");
173 		writew(0xFFFF, &i2c_base->stat);
174 		status = 0;
175 	}
176 
177 	return status;
178 }
179 
180 static void flush_fifo(struct i2c *i2c_base)
181 {
182 	u16 stat;
183 
184 	/*
185 	 * note: if you try and read data when its not there or ready
186 	 * you get a bus error
187 	 */
188 	while (1) {
189 		stat = readw(&i2c_base->stat);
190 		if (stat == I2C_STAT_RRDY) {
191 			readb(&i2c_base->data);
192 			writew(I2C_STAT_RRDY, &i2c_base->stat);
193 			udelay(1000);
194 		} else
195 			break;
196 	}
197 }
198 
199 static int __omap24_i2c_setspeed(struct i2c *i2c_base, uint speed,
200 				 int *waitdelay)
201 {
202 	int psc, fsscll = 0, fssclh = 0;
203 	int hsscll = 0, hssclh = 0;
204 	u32 scll = 0, sclh = 0;
205 
206 	if (speed >= OMAP_I2C_HIGH_SPEED) {
207 		/* High speed */
208 		psc = I2C_IP_CLK / I2C_INTERNAL_SAMPLING_CLK;
209 		psc -= 1;
210 		if (psc < I2C_PSC_MIN) {
211 			printf("Error : I2C unsupported prescaler %d\n", psc);
212 			return -1;
213 		}
214 
215 		/* For first phase of HS mode */
216 		fsscll = I2C_INTERNAL_SAMPLING_CLK / (2 * speed);
217 
218 		fssclh = fsscll;
219 
220 		fsscll -= I2C_HIGHSPEED_PHASE_ONE_SCLL_TRIM;
221 		fssclh -= I2C_HIGHSPEED_PHASE_ONE_SCLH_TRIM;
222 		if (((fsscll < 0) || (fssclh < 0)) ||
223 		    ((fsscll > 255) || (fssclh > 255))) {
224 			puts("Error : I2C initializing first phase clock\n");
225 			return -1;
226 		}
227 
228 		/* For second phase of HS mode */
229 		hsscll = hssclh = I2C_INTERNAL_SAMPLING_CLK / (2 * speed);
230 
231 		hsscll -= I2C_HIGHSPEED_PHASE_TWO_SCLL_TRIM;
232 		hssclh -= I2C_HIGHSPEED_PHASE_TWO_SCLH_TRIM;
233 		if (((fsscll < 0) || (fssclh < 0)) ||
234 		    ((fsscll > 255) || (fssclh > 255))) {
235 			puts("Error : I2C initializing second phase clock\n");
236 			return -1;
237 		}
238 
239 		scll = (unsigned int)hsscll << 8 | (unsigned int)fsscll;
240 		sclh = (unsigned int)hssclh << 8 | (unsigned int)fssclh;
241 
242 	} else {
243 		/* Standard and fast speed */
244 		psc = omap24_i2c_findpsc(&scll, &sclh, speed);
245 		if (0 > psc) {
246 			puts("Error : I2C initializing clock\n");
247 			return -1;
248 		}
249 	}
250 
251 	*waitdelay = (10000000 / speed) * 2; /* wait for 20 clkperiods */
252 	writew(0, &i2c_base->con);
253 	writew(psc, &i2c_base->psc);
254 	writew(scll, &i2c_base->scll);
255 	writew(sclh, &i2c_base->sclh);
256 	writew(I2C_CON_EN, &i2c_base->con);
257 	writew(0xFFFF, &i2c_base->stat);	/* clear all pending status */
258 
259 	return 0;
260 }
261 
262 static void omap24_i2c_deblock(struct i2c *i2c_base)
263 {
264 	int i;
265 	u16 systest;
266 	u16 orgsystest;
267 
268 	/* set test mode ST_EN = 1 */
269 	orgsystest = readw(&i2c_base->systest);
270 	systest = orgsystest;
271 	/* enable testmode */
272 	systest |= I2C_SYSTEST_ST_EN;
273 	writew(systest, &i2c_base->systest);
274 	systest &= ~I2C_SYSTEST_TMODE_MASK;
275 	systest |= 3 << I2C_SYSTEST_TMODE_SHIFT;
276 	writew(systest, &i2c_base->systest);
277 
278 	/* set SCL, SDA  = 1 */
279 	systest |= I2C_SYSTEST_SCL_O | I2C_SYSTEST_SDA_O;
280 	writew(systest, &i2c_base->systest);
281 	udelay(10);
282 
283 	/* toggle scl 9 clocks */
284 	for (i = 0; i < 9; i++) {
285 		/* SCL = 0 */
286 		systest &= ~I2C_SYSTEST_SCL_O;
287 		writew(systest, &i2c_base->systest);
288 		udelay(10);
289 		/* SCL = 1 */
290 		systest |= I2C_SYSTEST_SCL_O;
291 		writew(systest, &i2c_base->systest);
292 		udelay(10);
293 	}
294 
295 	/* send stop */
296 	systest &= ~I2C_SYSTEST_SDA_O;
297 	writew(systest, &i2c_base->systest);
298 	udelay(10);
299 	systest |= I2C_SYSTEST_SCL_O | I2C_SYSTEST_SDA_O;
300 	writew(systest, &i2c_base->systest);
301 	udelay(10);
302 
303 	/* restore original mode */
304 	writew(orgsystest, &i2c_base->systest);
305 }
306 
307 static void __omap24_i2c_init(struct i2c *i2c_base, int speed, int slaveadd,
308 			      int *waitdelay)
309 {
310 	int timeout = I2C_TIMEOUT;
311 	int deblock = 1;
312 
313 retry:
314 	if (readw(&i2c_base->con) & I2C_CON_EN) {
315 		writew(0, &i2c_base->con);
316 		udelay(50000);
317 	}
318 
319 	writew(0x2, &i2c_base->sysc); /* for ES2 after soft reset */
320 	udelay(1000);
321 
322 	writew(I2C_CON_EN, &i2c_base->con);
323 	while (!(readw(&i2c_base->syss) & I2C_SYSS_RDONE) && timeout--) {
324 		if (timeout <= 0) {
325 			puts("ERROR: Timeout in soft-reset\n");
326 			return;
327 		}
328 		udelay(1000);
329 	}
330 
331 	if (0 != __omap24_i2c_setspeed(i2c_base, speed, waitdelay)) {
332 		printf("ERROR: failed to setup I2C bus-speed!\n");
333 		return;
334 	}
335 
336 	/* own address */
337 	writew(slaveadd, &i2c_base->oa);
338 
339 #if defined(CONFIG_OMAP34XX)
340 	/*
341 	 * Have to enable interrupts for OMAP2/3, these IPs don't have
342 	 * an 'irqstatus_raw' register and we shall have to poll 'stat'
343 	 */
344 	writew(I2C_IE_XRDY_IE | I2C_IE_RRDY_IE | I2C_IE_ARDY_IE |
345 	       I2C_IE_NACK_IE | I2C_IE_AL_IE, &i2c_base->ie);
346 #endif
347 	udelay(1000);
348 	flush_fifo(i2c_base);
349 	writew(0xFFFF, &i2c_base->stat);
350 
351 	/* Handle possible failed I2C state */
352 	if (wait_for_bb(i2c_base, *waitdelay))
353 		if (deblock == 1) {
354 			omap24_i2c_deblock(i2c_base);
355 			deblock = 0;
356 			goto retry;
357 		}
358 }
359 
360 /*
361  * i2c_probe: Use write access. Allows to identify addresses that are
362  *            write-only (like the config register of dual-port EEPROMs)
363  */
364 static int __omap24_i2c_probe(struct i2c *i2c_base, int waitdelay, uchar chip)
365 {
366 	u16 status;
367 	int res = 1; /* default = fail */
368 
369 	if (chip == readw(&i2c_base->oa))
370 		return res;
371 
372 	/* Wait until bus is free */
373 	if (wait_for_bb(i2c_base, waitdelay))
374 		return res;
375 
376 	/* No data transfer, slave addr only */
377 	writew(chip, &i2c_base->sa);
378 	/* Stop bit needed here */
379 	writew(I2C_CON_EN | I2C_CON_MST | I2C_CON_STT | I2C_CON_TRX |
380 	       I2C_CON_STP, &i2c_base->con);
381 
382 	status = wait_for_event(i2c_base, waitdelay);
383 
384 	if ((status & ~I2C_STAT_XRDY) == 0 || (status & I2C_STAT_AL)) {
385 		/*
386 		 * With current high-level command implementation, notifying
387 		 * the user shall flood the console with 127 messages. If
388 		 * silent exit is desired upon unconfigured bus, remove the
389 		 * following 'if' section:
390 		 */
391 		if (status == I2C_STAT_XRDY)
392 			printf("i2c_probe: pads on bus probably not configured (status=0x%x)\n",
393 			       status);
394 
395 		goto pr_exit;
396 	}
397 
398 	/* Check for ACK (!NAK) */
399 	if (!(status & I2C_STAT_NACK)) {
400 		res = 0;				/* Device found */
401 		udelay(waitdelay);/* Required by AM335X in SPL */
402 		/* Abort transfer (force idle state) */
403 		writew(I2C_CON_MST | I2C_CON_TRX, &i2c_base->con); /* Reset */
404 		udelay(1000);
405 		writew(I2C_CON_EN | I2C_CON_MST | I2C_CON_TRX |
406 		       I2C_CON_STP, &i2c_base->con);		/* STP */
407 	}
408 pr_exit:
409 	flush_fifo(i2c_base);
410 	writew(0xFFFF, &i2c_base->stat);
411 	return res;
412 }
413 
414 /*
415  * i2c_read: Function now uses a single I2C read transaction with bulk transfer
416  *           of the requested number of bytes (note that the 'i2c md' command
417  *           limits this to 16 bytes anyway). If CONFIG_I2C_REPEATED_START is
418  *           defined in the board config header, this transaction shall be with
419  *           Repeated Start (Sr) between the address and data phases; otherwise
420  *           Stop-Start (P-S) shall be used (some I2C chips do require a P-S).
421  *           The address (reg offset) may be 0, 1 or 2 bytes long.
422  *           Function now reads correctly from chips that return more than one
423  *           byte of data per addressed register (like TI temperature sensors),
424  *           or that do not need a register address at all (such as some clock
425  *           distributors).
426  */
427 static int __omap24_i2c_read(struct i2c *i2c_base, int waitdelay, uchar chip,
428 			     uint addr, int alen, uchar *buffer, int len)
429 {
430 	int i2c_error = 0;
431 	u16 status;
432 
433 	if (alen < 0) {
434 		puts("I2C read: addr len < 0\n");
435 		return 1;
436 	}
437 	if (len < 0) {
438 		puts("I2C read: data len < 0\n");
439 		return 1;
440 	}
441 	if (buffer == NULL) {
442 		puts("I2C read: NULL pointer passed\n");
443 		return 1;
444 	}
445 
446 	if (alen > 2) {
447 		printf("I2C read: addr len %d not supported\n", alen);
448 		return 1;
449 	}
450 
451 	if (addr + len > (1 << 16)) {
452 		puts("I2C read: address out of range\n");
453 		return 1;
454 	}
455 
456 #ifdef CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW
457 	/*
458 	 * EEPROM chips that implement "address overflow" are ones
459 	 * like Catalyst 24WC04/08/16 which has 9/10/11 bits of
460 	 * address and the extra bits end up in the "chip address"
461 	 * bit slots. This makes a 24WC08 (1Kbyte) chip look like
462 	 * four 256 byte chips.
463 	 *
464 	 * Note that we consider the length of the address field to
465 	 * still be one byte because the extra address bits are
466 	 * hidden in the chip address.
467 	 */
468 	if (alen > 0)
469 		chip |= ((addr >> (alen * 8)) &
470 			 CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW);
471 #endif
472 
473 	/* Wait until bus not busy */
474 	if (wait_for_bb(i2c_base, waitdelay))
475 		return 1;
476 
477 	/* Zero, one or two bytes reg address (offset) */
478 	writew(alen, &i2c_base->cnt);
479 	/* Set slave address */
480 	writew(chip, &i2c_base->sa);
481 
482 	if (alen) {
483 		/* Must write reg offset first */
484 #ifdef CONFIG_I2C_REPEATED_START
485 		/* No stop bit, use Repeated Start (Sr) */
486 		writew(I2C_CON_EN | I2C_CON_MST | I2C_CON_STT |
487 		       I2C_CON_TRX, &i2c_base->con);
488 #else
489 		/* Stop - Start (P-S) */
490 		writew(I2C_CON_EN | I2C_CON_MST | I2C_CON_STT | I2C_CON_STP |
491 		       I2C_CON_TRX, &i2c_base->con);
492 #endif
493 		/* Send register offset */
494 		while (1) {
495 			status = wait_for_event(i2c_base, waitdelay);
496 			/* Try to identify bus that is not padconf'd for I2C */
497 			if (status == I2C_STAT_XRDY) {
498 				i2c_error = 2;
499 				printf("i2c_read (addr phase): pads on bus probably not configured (status=0x%x)\n",
500 				       status);
501 				goto rd_exit;
502 			}
503 			if (status == 0 || (status & I2C_STAT_NACK)) {
504 				i2c_error = 1;
505 				printf("i2c_read: error waiting for addr ACK (status=0x%x)\n",
506 				       status);
507 				goto rd_exit;
508 			}
509 			if (alen) {
510 				if (status & I2C_STAT_XRDY) {
511 					alen--;
512 					/* Do we have to use byte access? */
513 					writeb((addr >> (8 * alen)) & 0xff,
514 					       &i2c_base->data);
515 					writew(I2C_STAT_XRDY, &i2c_base->stat);
516 				}
517 			}
518 			if (status & I2C_STAT_ARDY) {
519 				writew(I2C_STAT_ARDY, &i2c_base->stat);
520 				break;
521 			}
522 		}
523 	}
524 	/* Set slave address */
525 	writew(chip, &i2c_base->sa);
526 	/* Read len bytes from slave */
527 	writew(len, &i2c_base->cnt);
528 	/* Need stop bit here */
529 	writew(I2C_CON_EN | I2C_CON_MST |
530 	       I2C_CON_STT | I2C_CON_STP,
531 	       &i2c_base->con);
532 
533 	/* Receive data */
534 	while (1) {
535 		status = wait_for_event(i2c_base, waitdelay);
536 		/*
537 		 * Try to identify bus that is not padconf'd for I2C. This
538 		 * state could be left over from previous transactions if
539 		 * the address phase is skipped due to alen=0.
540 		 */
541 		if (status == I2C_STAT_XRDY) {
542 			i2c_error = 2;
543 			printf("i2c_read (data phase): pads on bus probably not configured (status=0x%x)\n",
544 			       status);
545 			goto rd_exit;
546 		}
547 		if (status == 0 || (status & I2C_STAT_NACK)) {
548 			i2c_error = 1;
549 			goto rd_exit;
550 		}
551 		if (status & I2C_STAT_RRDY) {
552 			*buffer++ = readb(&i2c_base->data);
553 			writew(I2C_STAT_RRDY, &i2c_base->stat);
554 		}
555 		if (status & I2C_STAT_ARDY) {
556 			writew(I2C_STAT_ARDY, &i2c_base->stat);
557 			break;
558 		}
559 	}
560 
561 rd_exit:
562 	flush_fifo(i2c_base);
563 	writew(0xFFFF, &i2c_base->stat);
564 	return i2c_error;
565 }
566 
567 /* i2c_write: Address (reg offset) may be 0, 1 or 2 bytes long. */
568 static int __omap24_i2c_write(struct i2c *i2c_base, int waitdelay, uchar chip,
569 			      uint addr, int alen, uchar *buffer, int len)
570 {
571 	int i;
572 	u16 status;
573 	int i2c_error = 0;
574 	int timeout = I2C_TIMEOUT;
575 
576 	if (alen < 0) {
577 		puts("I2C write: addr len < 0\n");
578 		return 1;
579 	}
580 
581 	if (len < 0) {
582 		puts("I2C write: data len < 0\n");
583 		return 1;
584 	}
585 
586 	if (buffer == NULL) {
587 		puts("I2C write: NULL pointer passed\n");
588 		return 1;
589 	}
590 
591 	if (alen > 2) {
592 		printf("I2C write: addr len %d not supported\n", alen);
593 		return 1;
594 	}
595 
596 	if (addr + len > (1 << 16)) {
597 		printf("I2C write: address 0x%x + 0x%x out of range\n",
598 		       addr, len);
599 		return 1;
600 	}
601 
602 #ifdef CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW
603 	/*
604 	 * EEPROM chips that implement "address overflow" are ones
605 	 * like Catalyst 24WC04/08/16 which has 9/10/11 bits of
606 	 * address and the extra bits end up in the "chip address"
607 	 * bit slots. This makes a 24WC08 (1Kbyte) chip look like
608 	 * four 256 byte chips.
609 	 *
610 	 * Note that we consider the length of the address field to
611 	 * still be one byte because the extra address bits are
612 	 * hidden in the chip address.
613 	 */
614 	if (alen > 0)
615 		chip |= ((addr >> (alen * 8)) &
616 			 CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW);
617 #endif
618 
619 	/* Wait until bus not busy */
620 	if (wait_for_bb(i2c_base, waitdelay))
621 		return 1;
622 
623 	/* Start address phase - will write regoffset + len bytes data */
624 	writew(alen + len, &i2c_base->cnt);
625 	/* Set slave address */
626 	writew(chip, &i2c_base->sa);
627 	/* Stop bit needed here */
628 	writew(I2C_CON_EN | I2C_CON_MST | I2C_CON_STT | I2C_CON_TRX |
629 	       I2C_CON_STP, &i2c_base->con);
630 
631 	while (alen) {
632 		/* Must write reg offset (one or two bytes) */
633 		status = wait_for_event(i2c_base, waitdelay);
634 		/* Try to identify bus that is not padconf'd for I2C */
635 		if (status == I2C_STAT_XRDY) {
636 			i2c_error = 2;
637 			printf("i2c_write: pads on bus probably not configured (status=0x%x)\n",
638 			       status);
639 			goto wr_exit;
640 		}
641 		if (status == 0 || (status & I2C_STAT_NACK)) {
642 			i2c_error = 1;
643 			printf("i2c_write: error waiting for addr ACK (status=0x%x)\n",
644 			       status);
645 			goto wr_exit;
646 		}
647 		if (status & I2C_STAT_XRDY) {
648 			alen--;
649 			writeb((addr >> (8 * alen)) & 0xff, &i2c_base->data);
650 			writew(I2C_STAT_XRDY, &i2c_base->stat);
651 		} else {
652 			i2c_error = 1;
653 			printf("i2c_write: bus not ready for addr Tx (status=0x%x)\n",
654 			       status);
655 			goto wr_exit;
656 		}
657 	}
658 	/* Address phase is over, now write data */
659 	for (i = 0; i < len; i++) {
660 		status = wait_for_event(i2c_base, waitdelay);
661 		if (status == 0 || (status & I2C_STAT_NACK)) {
662 			i2c_error = 1;
663 			printf("i2c_write: error waiting for data ACK (status=0x%x)\n",
664 			       status);
665 			goto wr_exit;
666 		}
667 		if (status & I2C_STAT_XRDY) {
668 			writeb(buffer[i], &i2c_base->data);
669 			writew(I2C_STAT_XRDY, &i2c_base->stat);
670 		} else {
671 			i2c_error = 1;
672 			printf("i2c_write: bus not ready for data Tx (i=%d)\n",
673 			       i);
674 			goto wr_exit;
675 		}
676 	}
677 	/*
678 	 * poll ARDY bit for making sure that last byte really has been
679 	 * transferred on the bus.
680 	 */
681 	do {
682 		status = wait_for_event(i2c_base, waitdelay);
683 	} while (!(status & I2C_STAT_ARDY) && timeout--);
684 	if (timeout <= 0)
685 		printf("i2c_write: timed out writig last byte!\n");
686 
687 wr_exit:
688 	flush_fifo(i2c_base);
689 	writew(0xFFFF, &i2c_base->stat);
690 	return i2c_error;
691 }
692 
693 #ifndef CONFIG_DM_I2C
694 /*
695  * The legacy I2C functions. These need to get removed once
696  * all users of this driver are converted to DM.
697  */
698 static struct i2c *omap24_get_base(struct i2c_adapter *adap)
699 {
700 	switch (adap->hwadapnr) {
701 	case 0:
702 		return (struct i2c *)I2C_BASE1;
703 		break;
704 	case 1:
705 		return (struct i2c *)I2C_BASE2;
706 		break;
707 #if (CONFIG_SYS_I2C_BUS_MAX > 2)
708 	case 2:
709 		return (struct i2c *)I2C_BASE3;
710 		break;
711 #if (CONFIG_SYS_I2C_BUS_MAX > 3)
712 	case 3:
713 		return (struct i2c *)I2C_BASE4;
714 		break;
715 #if (CONFIG_SYS_I2C_BUS_MAX > 4)
716 	case 4:
717 		return (struct i2c *)I2C_BASE5;
718 		break;
719 #endif
720 #endif
721 #endif
722 	default:
723 		printf("wrong hwadapnr: %d\n", adap->hwadapnr);
724 		break;
725 	}
726 	return NULL;
727 }
728 
729 
730 static int omap24_i2c_read(struct i2c_adapter *adap, uchar chip, uint addr,
731 			   int alen, uchar *buffer, int len)
732 {
733 	struct i2c *i2c_base = omap24_get_base(adap);
734 
735 	return __omap24_i2c_read(i2c_base, adap->waitdelay, chip, addr,
736 				 alen, buffer, len);
737 }
738 
739 
740 static int omap24_i2c_write(struct i2c_adapter *adap, uchar chip, uint addr,
741 			    int alen, uchar *buffer, int len)
742 {
743 	struct i2c *i2c_base = omap24_get_base(adap);
744 
745 	return __omap24_i2c_write(i2c_base, adap->waitdelay, chip, addr,
746 				  alen, buffer, len);
747 }
748 
749 static uint omap24_i2c_setspeed(struct i2c_adapter *adap, uint speed)
750 {
751 	struct i2c *i2c_base = omap24_get_base(adap);
752 	int ret;
753 
754 	ret = __omap24_i2c_setspeed(i2c_base, speed, &adap->waitdelay);
755 	if (ret) {
756 		pr_err("%s: set i2c speed failed\n", __func__);
757 		return ret;
758 	}
759 
760 	adap->speed = speed;
761 
762 	return 0;
763 }
764 
765 static void omap24_i2c_init(struct i2c_adapter *adap, int speed, int slaveadd)
766 {
767 	struct i2c *i2c_base = omap24_get_base(adap);
768 
769 	return __omap24_i2c_init(i2c_base, speed, slaveadd, &adap->waitdelay);
770 }
771 
772 static int omap24_i2c_probe(struct i2c_adapter *adap, uchar chip)
773 {
774 	struct i2c *i2c_base = omap24_get_base(adap);
775 
776 	return __omap24_i2c_probe(i2c_base, adap->waitdelay, chip);
777 }
778 
779 #if !defined(CONFIG_SYS_OMAP24_I2C_SPEED1)
780 #define CONFIG_SYS_OMAP24_I2C_SPEED1 CONFIG_SYS_OMAP24_I2C_SPEED
781 #endif
782 #if !defined(CONFIG_SYS_OMAP24_I2C_SLAVE1)
783 #define CONFIG_SYS_OMAP24_I2C_SLAVE1 CONFIG_SYS_OMAP24_I2C_SLAVE
784 #endif
785 
786 U_BOOT_I2C_ADAP_COMPLETE(omap24_0, omap24_i2c_init, omap24_i2c_probe,
787 			 omap24_i2c_read, omap24_i2c_write, omap24_i2c_setspeed,
788 			 CONFIG_SYS_OMAP24_I2C_SPEED,
789 			 CONFIG_SYS_OMAP24_I2C_SLAVE,
790 			 0)
791 U_BOOT_I2C_ADAP_COMPLETE(omap24_1, omap24_i2c_init, omap24_i2c_probe,
792 			 omap24_i2c_read, omap24_i2c_write, omap24_i2c_setspeed,
793 			 CONFIG_SYS_OMAP24_I2C_SPEED1,
794 			 CONFIG_SYS_OMAP24_I2C_SLAVE1,
795 			 1)
796 #if (CONFIG_SYS_I2C_BUS_MAX > 2)
797 #if !defined(CONFIG_SYS_OMAP24_I2C_SPEED2)
798 #define CONFIG_SYS_OMAP24_I2C_SPEED2 CONFIG_SYS_OMAP24_I2C_SPEED
799 #endif
800 #if !defined(CONFIG_SYS_OMAP24_I2C_SLAVE2)
801 #define CONFIG_SYS_OMAP24_I2C_SLAVE2 CONFIG_SYS_OMAP24_I2C_SLAVE
802 #endif
803 
804 U_BOOT_I2C_ADAP_COMPLETE(omap24_2, omap24_i2c_init, omap24_i2c_probe,
805 			 omap24_i2c_read, omap24_i2c_write, NULL,
806 			 CONFIG_SYS_OMAP24_I2C_SPEED2,
807 			 CONFIG_SYS_OMAP24_I2C_SLAVE2,
808 			 2)
809 #if (CONFIG_SYS_I2C_BUS_MAX > 3)
810 #if !defined(CONFIG_SYS_OMAP24_I2C_SPEED3)
811 #define CONFIG_SYS_OMAP24_I2C_SPEED3 CONFIG_SYS_OMAP24_I2C_SPEED
812 #endif
813 #if !defined(CONFIG_SYS_OMAP24_I2C_SLAVE3)
814 #define CONFIG_SYS_OMAP24_I2C_SLAVE3 CONFIG_SYS_OMAP24_I2C_SLAVE
815 #endif
816 
817 U_BOOT_I2C_ADAP_COMPLETE(omap24_3, omap24_i2c_init, omap24_i2c_probe,
818 			 omap24_i2c_read, omap24_i2c_write, NULL,
819 			 CONFIG_SYS_OMAP24_I2C_SPEED3,
820 			 CONFIG_SYS_OMAP24_I2C_SLAVE3,
821 			 3)
822 #if (CONFIG_SYS_I2C_BUS_MAX > 4)
823 #if !defined(CONFIG_SYS_OMAP24_I2C_SPEED4)
824 #define CONFIG_SYS_OMAP24_I2C_SPEED4 CONFIG_SYS_OMAP24_I2C_SPEED
825 #endif
826 #if !defined(CONFIG_SYS_OMAP24_I2C_SLAVE4)
827 #define CONFIG_SYS_OMAP24_I2C_SLAVE4 CONFIG_SYS_OMAP24_I2C_SLAVE
828 #endif
829 
830 U_BOOT_I2C_ADAP_COMPLETE(omap24_4, omap24_i2c_init, omap24_i2c_probe,
831 			 omap24_i2c_read, omap24_i2c_write, NULL,
832 			 CONFIG_SYS_OMAP24_I2C_SPEED4,
833 			 CONFIG_SYS_OMAP24_I2C_SLAVE4,
834 			 4)
835 #endif
836 #endif
837 #endif
838 
839 #else /* CONFIG_DM_I2C */
840 
841 static int omap_i2c_xfer(struct udevice *bus, struct i2c_msg *msg, int nmsgs)
842 {
843 	struct omap_i2c *priv = dev_get_priv(bus);
844 	int ret;
845 
846 	debug("i2c_xfer: %d messages\n", nmsgs);
847 	for (; nmsgs > 0; nmsgs--, msg++) {
848 		debug("i2c_xfer: chip=0x%x, len=0x%x\n", msg->addr, msg->len);
849 		if (msg->flags & I2C_M_RD) {
850 			ret = __omap24_i2c_read(priv->regs, priv->waitdelay,
851 						msg->addr, 0, 0, msg->buf,
852 						msg->len);
853 		} else {
854 			ret = __omap24_i2c_write(priv->regs, priv->waitdelay,
855 						 msg->addr, 0, 0, msg->buf,
856 						 msg->len);
857 		}
858 		if (ret) {
859 			debug("i2c_write: error sending\n");
860 			return -EREMOTEIO;
861 		}
862 	}
863 
864 	return 0;
865 }
866 
867 static int omap_i2c_set_bus_speed(struct udevice *bus, unsigned int speed)
868 {
869 	struct omap_i2c *priv = dev_get_priv(bus);
870 
871 	priv->speed = speed;
872 
873 	return __omap24_i2c_setspeed(priv->regs, speed, &priv->waitdelay);
874 }
875 
876 static int omap_i2c_probe_chip(struct udevice *bus, uint chip_addr,
877 				     uint chip_flags)
878 {
879 	struct omap_i2c *priv = dev_get_priv(bus);
880 
881 	return __omap24_i2c_probe(priv->regs, priv->waitdelay, chip_addr);
882 }
883 
884 static int omap_i2c_probe(struct udevice *bus)
885 {
886 	struct omap_i2c *priv = dev_get_priv(bus);
887 
888 	__omap24_i2c_init(priv->regs, priv->speed, 0, &priv->waitdelay);
889 
890 	return 0;
891 }
892 
893 static int omap_i2c_ofdata_to_platdata(struct udevice *bus)
894 {
895 	struct omap_i2c *priv = dev_get_priv(bus);
896 
897 	priv->regs = map_physmem(devfdt_get_addr(bus), sizeof(void *),
898 				 MAP_NOCACHE);
899 	priv->speed = CONFIG_SYS_OMAP24_I2C_SPEED;
900 
901 	return 0;
902 }
903 
904 static const struct dm_i2c_ops omap_i2c_ops = {
905 	.xfer		= omap_i2c_xfer,
906 	.probe_chip	= omap_i2c_probe_chip,
907 	.set_bus_speed	= omap_i2c_set_bus_speed,
908 };
909 
910 static const struct udevice_id omap_i2c_ids[] = {
911 	{ .compatible = "ti,omap3-i2c" },
912 	{ .compatible = "ti,omap4-i2c" },
913 	{ }
914 };
915 
916 U_BOOT_DRIVER(i2c_omap) = {
917 	.name	= "i2c_omap",
918 	.id	= UCLASS_I2C,
919 	.of_match = omap_i2c_ids,
920 	.ofdata_to_platdata = omap_i2c_ofdata_to_platdata,
921 	.probe	= omap_i2c_probe,
922 	.priv_auto_alloc_size = sizeof(struct omap_i2c),
923 	.ops	= &omap_i2c_ops,
924 	.flags  = DM_FLAG_PRE_RELOC,
925 };
926 
927 #endif /* CONFIG_DM_I2C */
928