xref: /openbmc/u-boot/drivers/i2c/omap24xx_i2c.c (revision bf9012b8)
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 DECLARE_GLOBAL_DATA_PTR;
51 
52 #define I2C_TIMEOUT	1000
53 
54 /* Absolutely safe for status update at 100 kHz I2C: */
55 #define I2C_WAIT	200
56 
57 struct omap_i2c {
58 	struct udevice *clk;
59 	struct i2c *regs;
60 	unsigned int speed;
61 	int waitdelay;
62 	int clk_id;
63 };
64 
65 static int omap24_i2c_findpsc(u32 *pscl, u32 *psch, uint speed)
66 {
67 	unsigned long internal_clk = 0, fclk;
68 	unsigned int prescaler;
69 
70 	/*
71 	 * This method is only called for Standard and Fast Mode speeds
72 	 *
73 	 * For some TI SoCs it is explicitly written in TRM (e,g, SPRUHZ6G,
74 	 * page 5685, Table 24-7)
75 	 * that the internal I2C clock (after prescaler) should be between
76 	 * 7-12 MHz (at least for Fast Mode (FS)).
77 	 *
78 	 * Such approach is used in v4.9 Linux kernel in:
79 	 * ./drivers/i2c/busses/i2c-omap.c (omap_i2c_init function).
80 	 */
81 
82 	speed /= 1000; /* convert speed to kHz */
83 
84 	if (speed > 100)
85 		internal_clk = 9600;
86 	else
87 		internal_clk = 4000;
88 
89 	fclk = I2C_IP_CLK / 1000;
90 	prescaler = fclk / internal_clk;
91 	prescaler = prescaler - 1;
92 
93 	if (speed > 100) {
94 		unsigned long scl;
95 
96 		/* Fast mode */
97 		scl = internal_clk / speed;
98 		*pscl = scl - (scl / 3) - I2C_FASTSPEED_SCLL_TRIM;
99 		*psch = (scl / 3) - I2C_FASTSPEED_SCLH_TRIM;
100 	} else {
101 		/* Standard mode */
102 		*pscl = internal_clk / (speed * 2) - I2C_FASTSPEED_SCLL_TRIM;
103 		*psch = internal_clk / (speed * 2) - I2C_FASTSPEED_SCLH_TRIM;
104 	}
105 
106 	debug("%s: speed [kHz]: %d psc: 0x%x sscl: 0x%x ssch: 0x%x\n",
107 	      __func__, speed, prescaler, *pscl, *psch);
108 
109 	if (*pscl <= 0 || *psch <= 0 || prescaler <= 0)
110 		return -EINVAL;
111 
112 	return prescaler;
113 }
114 
115 /*
116  * Wait for the bus to be free by checking the Bus Busy (BB)
117  * bit to become clear
118  */
119 static int wait_for_bb(struct i2c *i2c_base, int waitdelay)
120 {
121 	int timeout = I2C_TIMEOUT;
122 	u16 stat;
123 
124 	writew(0xFFFF, &i2c_base->stat);	/* clear current interrupts...*/
125 #if defined(CONFIG_OMAP34XX)
126 	while ((stat = readw(&i2c_base->stat) & I2C_STAT_BB) && timeout--) {
127 #else
128 	/* Read RAW status */
129 	while ((stat = readw(&i2c_base->irqstatus_raw) &
130 		I2C_STAT_BB) && timeout--) {
131 #endif
132 		writew(stat, &i2c_base->stat);
133 		udelay(waitdelay);
134 	}
135 
136 	if (timeout <= 0) {
137 		printf("Timed out in wait_for_bb: status=%04x\n",
138 		       stat);
139 		return 1;
140 	}
141 	writew(0xFFFF, &i2c_base->stat);	 /* clear delayed stuff*/
142 	return 0;
143 }
144 
145 /*
146  * Wait for the I2C controller to complete current action
147  * and update status
148  */
149 static u16 wait_for_event(struct i2c *i2c_base, int waitdelay)
150 {
151 	u16 status;
152 	int timeout = I2C_TIMEOUT;
153 
154 	do {
155 		udelay(waitdelay);
156 #if defined(CONFIG_OMAP34XX)
157 		status = readw(&i2c_base->stat);
158 #else
159 		/* Read RAW status */
160 		status = readw(&i2c_base->irqstatus_raw);
161 #endif
162 	} while (!(status &
163 		   (I2C_STAT_ROVR | I2C_STAT_XUDF | I2C_STAT_XRDY |
164 		    I2C_STAT_RRDY | I2C_STAT_ARDY | I2C_STAT_NACK |
165 		    I2C_STAT_AL)) && timeout--);
166 
167 	if (timeout <= 0) {
168 		printf("Timed out in wait_for_event: status=%04x\n",
169 		       status);
170 		/*
171 		 * If status is still 0 here, probably the bus pads have
172 		 * not been configured for I2C, and/or pull-ups are missing.
173 		 */
174 		printf("Check if pads/pull-ups of bus are properly configured\n");
175 		writew(0xFFFF, &i2c_base->stat);
176 		status = 0;
177 	}
178 
179 	return status;
180 }
181 
182 static void flush_fifo(struct i2c *i2c_base)
183 {
184 	u16 stat;
185 
186 	/*
187 	 * note: if you try and read data when its not there or ready
188 	 * you get a bus error
189 	 */
190 	while (1) {
191 		stat = readw(&i2c_base->stat);
192 		if (stat == I2C_STAT_RRDY) {
193 			readb(&i2c_base->data);
194 			writew(I2C_STAT_RRDY, &i2c_base->stat);
195 			udelay(1000);
196 		} else
197 			break;
198 	}
199 }
200 
201 static int __omap24_i2c_setspeed(struct i2c *i2c_base, uint speed,
202 				 int *waitdelay)
203 {
204 	int psc, fsscll = 0, fssclh = 0;
205 	int hsscll = 0, hssclh = 0;
206 	u32 scll = 0, sclh = 0;
207 
208 	if (speed >= OMAP_I2C_HIGH_SPEED) {
209 		/* High speed */
210 		psc = I2C_IP_CLK / I2C_INTERNAL_SAMPLING_CLK;
211 		psc -= 1;
212 		if (psc < I2C_PSC_MIN) {
213 			printf("Error : I2C unsupported prescaler %d\n", psc);
214 			return -1;
215 		}
216 
217 		/* For first phase of HS mode */
218 		fsscll = I2C_INTERNAL_SAMPLING_CLK / (2 * speed);
219 
220 		fssclh = fsscll;
221 
222 		fsscll -= I2C_HIGHSPEED_PHASE_ONE_SCLL_TRIM;
223 		fssclh -= I2C_HIGHSPEED_PHASE_ONE_SCLH_TRIM;
224 		if (((fsscll < 0) || (fssclh < 0)) ||
225 		    ((fsscll > 255) || (fssclh > 255))) {
226 			puts("Error : I2C initializing first phase clock\n");
227 			return -1;
228 		}
229 
230 		/* For second phase of HS mode */
231 		hsscll = hssclh = I2C_INTERNAL_SAMPLING_CLK / (2 * speed);
232 
233 		hsscll -= I2C_HIGHSPEED_PHASE_TWO_SCLL_TRIM;
234 		hssclh -= I2C_HIGHSPEED_PHASE_TWO_SCLH_TRIM;
235 		if (((fsscll < 0) || (fssclh < 0)) ||
236 		    ((fsscll > 255) || (fssclh > 255))) {
237 			puts("Error : I2C initializing second phase clock\n");
238 			return -1;
239 		}
240 
241 		scll = (unsigned int)hsscll << 8 | (unsigned int)fsscll;
242 		sclh = (unsigned int)hssclh << 8 | (unsigned int)fssclh;
243 
244 	} else {
245 		/* Standard and fast speed */
246 		psc = omap24_i2c_findpsc(&scll, &sclh, speed);
247 		if (0 > psc) {
248 			puts("Error : I2C initializing clock\n");
249 			return -1;
250 		}
251 	}
252 
253 	*waitdelay = (10000000 / speed) * 2; /* wait for 20 clkperiods */
254 	writew(0, &i2c_base->con);
255 	writew(psc, &i2c_base->psc);
256 	writew(scll, &i2c_base->scll);
257 	writew(sclh, &i2c_base->sclh);
258 	writew(I2C_CON_EN, &i2c_base->con);
259 	writew(0xFFFF, &i2c_base->stat);	/* clear all pending status */
260 
261 	return 0;
262 }
263 
264 static void omap24_i2c_deblock(struct i2c *i2c_base)
265 {
266 	int i;
267 	u16 systest;
268 	u16 orgsystest;
269 
270 	/* set test mode ST_EN = 1 */
271 	orgsystest = readw(&i2c_base->systest);
272 	systest = orgsystest;
273 	/* enable testmode */
274 	systest |= I2C_SYSTEST_ST_EN;
275 	writew(systest, &i2c_base->systest);
276 	systest &= ~I2C_SYSTEST_TMODE_MASK;
277 	systest |= 3 << I2C_SYSTEST_TMODE_SHIFT;
278 	writew(systest, &i2c_base->systest);
279 
280 	/* set SCL, SDA  = 1 */
281 	systest |= I2C_SYSTEST_SCL_O | I2C_SYSTEST_SDA_O;
282 	writew(systest, &i2c_base->systest);
283 	udelay(10);
284 
285 	/* toggle scl 9 clocks */
286 	for (i = 0; i < 9; i++) {
287 		/* SCL = 0 */
288 		systest &= ~I2C_SYSTEST_SCL_O;
289 		writew(systest, &i2c_base->systest);
290 		udelay(10);
291 		/* SCL = 1 */
292 		systest |= I2C_SYSTEST_SCL_O;
293 		writew(systest, &i2c_base->systest);
294 		udelay(10);
295 	}
296 
297 	/* send stop */
298 	systest &= ~I2C_SYSTEST_SDA_O;
299 	writew(systest, &i2c_base->systest);
300 	udelay(10);
301 	systest |= I2C_SYSTEST_SCL_O | I2C_SYSTEST_SDA_O;
302 	writew(systest, &i2c_base->systest);
303 	udelay(10);
304 
305 	/* restore original mode */
306 	writew(orgsystest, &i2c_base->systest);
307 }
308 
309 static void __omap24_i2c_init(struct i2c *i2c_base, int speed, int slaveadd,
310 			      int *waitdelay)
311 {
312 	int timeout = I2C_TIMEOUT;
313 	int deblock = 1;
314 
315 retry:
316 	if (readw(&i2c_base->con) & I2C_CON_EN) {
317 		writew(0, &i2c_base->con);
318 		udelay(50000);
319 	}
320 
321 	writew(0x2, &i2c_base->sysc); /* for ES2 after soft reset */
322 	udelay(1000);
323 
324 	writew(I2C_CON_EN, &i2c_base->con);
325 	while (!(readw(&i2c_base->syss) & I2C_SYSS_RDONE) && timeout--) {
326 		if (timeout <= 0) {
327 			puts("ERROR: Timeout in soft-reset\n");
328 			return;
329 		}
330 		udelay(1000);
331 	}
332 
333 	if (0 != __omap24_i2c_setspeed(i2c_base, speed, waitdelay)) {
334 		printf("ERROR: failed to setup I2C bus-speed!\n");
335 		return;
336 	}
337 
338 	/* own address */
339 	writew(slaveadd, &i2c_base->oa);
340 
341 #if defined(CONFIG_OMAP34XX)
342 	/*
343 	 * Have to enable interrupts for OMAP2/3, these IPs don't have
344 	 * an 'irqstatus_raw' register and we shall have to poll 'stat'
345 	 */
346 	writew(I2C_IE_XRDY_IE | I2C_IE_RRDY_IE | I2C_IE_ARDY_IE |
347 	       I2C_IE_NACK_IE | I2C_IE_AL_IE, &i2c_base->ie);
348 #endif
349 	udelay(1000);
350 	flush_fifo(i2c_base);
351 	writew(0xFFFF, &i2c_base->stat);
352 
353 	/* Handle possible failed I2C state */
354 	if (wait_for_bb(i2c_base, *waitdelay))
355 		if (deblock == 1) {
356 			omap24_i2c_deblock(i2c_base);
357 			deblock = 0;
358 			goto retry;
359 		}
360 }
361 
362 /*
363  * i2c_probe: Use write access. Allows to identify addresses that are
364  *            write-only (like the config register of dual-port EEPROMs)
365  */
366 static int __omap24_i2c_probe(struct i2c *i2c_base, int waitdelay, uchar chip)
367 {
368 	u16 status;
369 	int res = 1; /* default = fail */
370 
371 	if (chip == readw(&i2c_base->oa))
372 		return res;
373 
374 	/* Wait until bus is free */
375 	if (wait_for_bb(i2c_base, waitdelay))
376 		return res;
377 
378 	/* No data transfer, slave addr only */
379 	writew(chip, &i2c_base->sa);
380 	/* Stop bit needed here */
381 	writew(I2C_CON_EN | I2C_CON_MST | I2C_CON_STT | I2C_CON_TRX |
382 	       I2C_CON_STP, &i2c_base->con);
383 
384 	status = wait_for_event(i2c_base, waitdelay);
385 
386 	if ((status & ~I2C_STAT_XRDY) == 0 || (status & I2C_STAT_AL)) {
387 		/*
388 		 * With current high-level command implementation, notifying
389 		 * the user shall flood the console with 127 messages. If
390 		 * silent exit is desired upon unconfigured bus, remove the
391 		 * following 'if' section:
392 		 */
393 		if (status == I2C_STAT_XRDY)
394 			printf("i2c_probe: pads on bus probably not configured (status=0x%x)\n",
395 			       status);
396 
397 		goto pr_exit;
398 	}
399 
400 	/* Check for ACK (!NAK) */
401 	if (!(status & I2C_STAT_NACK)) {
402 		res = 0;				/* Device found */
403 		udelay(waitdelay);/* Required by AM335X in SPL */
404 		/* Abort transfer (force idle state) */
405 		writew(I2C_CON_MST | I2C_CON_TRX, &i2c_base->con); /* Reset */
406 		udelay(1000);
407 		writew(I2C_CON_EN | I2C_CON_MST | I2C_CON_TRX |
408 		       I2C_CON_STP, &i2c_base->con);		/* STP */
409 	}
410 pr_exit:
411 	flush_fifo(i2c_base);
412 	writew(0xFFFF, &i2c_base->stat);
413 	return res;
414 }
415 
416 /*
417  * i2c_read: Function now uses a single I2C read transaction with bulk transfer
418  *           of the requested number of bytes (note that the 'i2c md' command
419  *           limits this to 16 bytes anyway). If CONFIG_I2C_REPEATED_START is
420  *           defined in the board config header, this transaction shall be with
421  *           Repeated Start (Sr) between the address and data phases; otherwise
422  *           Stop-Start (P-S) shall be used (some I2C chips do require a P-S).
423  *           The address (reg offset) may be 0, 1 or 2 bytes long.
424  *           Function now reads correctly from chips that return more than one
425  *           byte of data per addressed register (like TI temperature sensors),
426  *           or that do not need a register address at all (such as some clock
427  *           distributors).
428  */
429 static int __omap24_i2c_read(struct i2c *i2c_base, int waitdelay, uchar chip,
430 			     uint addr, int alen, uchar *buffer, int len)
431 {
432 	int i2c_error = 0;
433 	u16 status;
434 
435 	if (alen < 0) {
436 		puts("I2C read: addr len < 0\n");
437 		return 1;
438 	}
439 	if (len < 0) {
440 		puts("I2C read: data len < 0\n");
441 		return 1;
442 	}
443 	if (buffer == NULL) {
444 		puts("I2C read: NULL pointer passed\n");
445 		return 1;
446 	}
447 
448 	if (alen > 2) {
449 		printf("I2C read: addr len %d not supported\n", alen);
450 		return 1;
451 	}
452 
453 	if (addr + len > (1 << 16)) {
454 		puts("I2C read: address out of range\n");
455 		return 1;
456 	}
457 
458 #ifdef CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW
459 	/*
460 	 * EEPROM chips that implement "address overflow" are ones
461 	 * like Catalyst 24WC04/08/16 which has 9/10/11 bits of
462 	 * address and the extra bits end up in the "chip address"
463 	 * bit slots. This makes a 24WC08 (1Kbyte) chip look like
464 	 * four 256 byte chips.
465 	 *
466 	 * Note that we consider the length of the address field to
467 	 * still be one byte because the extra address bits are
468 	 * hidden in the chip address.
469 	 */
470 	if (alen > 0)
471 		chip |= ((addr >> (alen * 8)) &
472 			 CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW);
473 #endif
474 
475 	/* Wait until bus not busy */
476 	if (wait_for_bb(i2c_base, waitdelay))
477 		return 1;
478 
479 	/* Zero, one or two bytes reg address (offset) */
480 	writew(alen, &i2c_base->cnt);
481 	/* Set slave address */
482 	writew(chip, &i2c_base->sa);
483 
484 	if (alen) {
485 		/* Must write reg offset first */
486 #ifdef CONFIG_I2C_REPEATED_START
487 		/* No stop bit, use Repeated Start (Sr) */
488 		writew(I2C_CON_EN | I2C_CON_MST | I2C_CON_STT |
489 		       I2C_CON_TRX, &i2c_base->con);
490 #else
491 		/* Stop - Start (P-S) */
492 		writew(I2C_CON_EN | I2C_CON_MST | I2C_CON_STT | I2C_CON_STP |
493 		       I2C_CON_TRX, &i2c_base->con);
494 #endif
495 		/* Send register offset */
496 		while (1) {
497 			status = wait_for_event(i2c_base, waitdelay);
498 			/* Try to identify bus that is not padconf'd for I2C */
499 			if (status == I2C_STAT_XRDY) {
500 				i2c_error = 2;
501 				printf("i2c_read (addr phase): pads on bus probably not configured (status=0x%x)\n",
502 				       status);
503 				goto rd_exit;
504 			}
505 			if (status == 0 || (status & I2C_STAT_NACK)) {
506 				i2c_error = 1;
507 				printf("i2c_read: error waiting for addr ACK (status=0x%x)\n",
508 				       status);
509 				goto rd_exit;
510 			}
511 			if (alen) {
512 				if (status & I2C_STAT_XRDY) {
513 					alen--;
514 					/* Do we have to use byte access? */
515 					writeb((addr >> (8 * alen)) & 0xff,
516 					       &i2c_base->data);
517 					writew(I2C_STAT_XRDY, &i2c_base->stat);
518 				}
519 			}
520 			if (status & I2C_STAT_ARDY) {
521 				writew(I2C_STAT_ARDY, &i2c_base->stat);
522 				break;
523 			}
524 		}
525 	}
526 	/* Set slave address */
527 	writew(chip, &i2c_base->sa);
528 	/* Read len bytes from slave */
529 	writew(len, &i2c_base->cnt);
530 	/* Need stop bit here */
531 	writew(I2C_CON_EN | I2C_CON_MST |
532 	       I2C_CON_STT | I2C_CON_STP,
533 	       &i2c_base->con);
534 
535 	/* Receive data */
536 	while (1) {
537 		status = wait_for_event(i2c_base, waitdelay);
538 		/*
539 		 * Try to identify bus that is not padconf'd for I2C. This
540 		 * state could be left over from previous transactions if
541 		 * the address phase is skipped due to alen=0.
542 		 */
543 		if (status == I2C_STAT_XRDY) {
544 			i2c_error = 2;
545 			printf("i2c_read (data phase): pads on bus probably not configured (status=0x%x)\n",
546 			       status);
547 			goto rd_exit;
548 		}
549 		if (status == 0 || (status & I2C_STAT_NACK)) {
550 			i2c_error = 1;
551 			goto rd_exit;
552 		}
553 		if (status & I2C_STAT_RRDY) {
554 			*buffer++ = readb(&i2c_base->data);
555 			writew(I2C_STAT_RRDY, &i2c_base->stat);
556 		}
557 		if (status & I2C_STAT_ARDY) {
558 			writew(I2C_STAT_ARDY, &i2c_base->stat);
559 			break;
560 		}
561 	}
562 
563 rd_exit:
564 	flush_fifo(i2c_base);
565 	writew(0xFFFF, &i2c_base->stat);
566 	return i2c_error;
567 }
568 
569 /* i2c_write: Address (reg offset) may be 0, 1 or 2 bytes long. */
570 static int __omap24_i2c_write(struct i2c *i2c_base, int waitdelay, uchar chip,
571 			      uint addr, int alen, uchar *buffer, int len)
572 {
573 	int i;
574 	u16 status;
575 	int i2c_error = 0;
576 	int timeout = I2C_TIMEOUT;
577 
578 	if (alen < 0) {
579 		puts("I2C write: addr len < 0\n");
580 		return 1;
581 	}
582 
583 	if (len < 0) {
584 		puts("I2C write: data len < 0\n");
585 		return 1;
586 	}
587 
588 	if (buffer == NULL) {
589 		puts("I2C write: NULL pointer passed\n");
590 		return 1;
591 	}
592 
593 	if (alen > 2) {
594 		printf("I2C write: addr len %d not supported\n", alen);
595 		return 1;
596 	}
597 
598 	if (addr + len > (1 << 16)) {
599 		printf("I2C write: address 0x%x + 0x%x out of range\n",
600 		       addr, len);
601 		return 1;
602 	}
603 
604 #ifdef CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW
605 	/*
606 	 * EEPROM chips that implement "address overflow" are ones
607 	 * like Catalyst 24WC04/08/16 which has 9/10/11 bits of
608 	 * address and the extra bits end up in the "chip address"
609 	 * bit slots. This makes a 24WC08 (1Kbyte) chip look like
610 	 * four 256 byte chips.
611 	 *
612 	 * Note that we consider the length of the address field to
613 	 * still be one byte because the extra address bits are
614 	 * hidden in the chip address.
615 	 */
616 	if (alen > 0)
617 		chip |= ((addr >> (alen * 8)) &
618 			 CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW);
619 #endif
620 
621 	/* Wait until bus not busy */
622 	if (wait_for_bb(i2c_base, waitdelay))
623 		return 1;
624 
625 	/* Start address phase - will write regoffset + len bytes data */
626 	writew(alen + len, &i2c_base->cnt);
627 	/* Set slave address */
628 	writew(chip, &i2c_base->sa);
629 	/* Stop bit needed here */
630 	writew(I2C_CON_EN | I2C_CON_MST | I2C_CON_STT | I2C_CON_TRX |
631 	       I2C_CON_STP, &i2c_base->con);
632 
633 	while (alen) {
634 		/* Must write reg offset (one or two bytes) */
635 		status = wait_for_event(i2c_base, waitdelay);
636 		/* Try to identify bus that is not padconf'd for I2C */
637 		if (status == I2C_STAT_XRDY) {
638 			i2c_error = 2;
639 			printf("i2c_write: pads on bus probably not configured (status=0x%x)\n",
640 			       status);
641 			goto wr_exit;
642 		}
643 		if (status == 0 || (status & I2C_STAT_NACK)) {
644 			i2c_error = 1;
645 			printf("i2c_write: error waiting for addr ACK (status=0x%x)\n",
646 			       status);
647 			goto wr_exit;
648 		}
649 		if (status & I2C_STAT_XRDY) {
650 			alen--;
651 			writeb((addr >> (8 * alen)) & 0xff, &i2c_base->data);
652 			writew(I2C_STAT_XRDY, &i2c_base->stat);
653 		} else {
654 			i2c_error = 1;
655 			printf("i2c_write: bus not ready for addr Tx (status=0x%x)\n",
656 			       status);
657 			goto wr_exit;
658 		}
659 	}
660 	/* Address phase is over, now write data */
661 	for (i = 0; i < len; i++) {
662 		status = wait_for_event(i2c_base, waitdelay);
663 		if (status == 0 || (status & I2C_STAT_NACK)) {
664 			i2c_error = 1;
665 			printf("i2c_write: error waiting for data ACK (status=0x%x)\n",
666 			       status);
667 			goto wr_exit;
668 		}
669 		if (status & I2C_STAT_XRDY) {
670 			writeb(buffer[i], &i2c_base->data);
671 			writew(I2C_STAT_XRDY, &i2c_base->stat);
672 		} else {
673 			i2c_error = 1;
674 			printf("i2c_write: bus not ready for data Tx (i=%d)\n",
675 			       i);
676 			goto wr_exit;
677 		}
678 	}
679 	/*
680 	 * poll ARDY bit for making sure that last byte really has been
681 	 * transferred on the bus.
682 	 */
683 	do {
684 		status = wait_for_event(i2c_base, waitdelay);
685 	} while (!(status & I2C_STAT_ARDY) && timeout--);
686 	if (timeout <= 0)
687 		printf("i2c_write: timed out writig last byte!\n");
688 
689 wr_exit:
690 	flush_fifo(i2c_base);
691 	writew(0xFFFF, &i2c_base->stat);
692 	return i2c_error;
693 }
694 
695 #ifndef CONFIG_DM_I2C
696 /*
697  * The legacy I2C functions. These need to get removed once
698  * all users of this driver are converted to DM.
699  */
700 static struct i2c *omap24_get_base(struct i2c_adapter *adap)
701 {
702 	switch (adap->hwadapnr) {
703 	case 0:
704 		return (struct i2c *)I2C_BASE1;
705 		break;
706 	case 1:
707 		return (struct i2c *)I2C_BASE2;
708 		break;
709 #if (I2C_BUS_MAX > 2)
710 	case 2:
711 		return (struct i2c *)I2C_BASE3;
712 		break;
713 #if (I2C_BUS_MAX > 3)
714 	case 3:
715 		return (struct i2c *)I2C_BASE4;
716 		break;
717 #if (I2C_BUS_MAX > 4)
718 	case 4:
719 		return (struct i2c *)I2C_BASE5;
720 		break;
721 #endif
722 #endif
723 #endif
724 	default:
725 		printf("wrong hwadapnr: %d\n", adap->hwadapnr);
726 		break;
727 	}
728 	return NULL;
729 }
730 
731 
732 static int omap24_i2c_read(struct i2c_adapter *adap, uchar chip, uint addr,
733 			   int alen, uchar *buffer, int len)
734 {
735 	struct i2c *i2c_base = omap24_get_base(adap);
736 
737 	return __omap24_i2c_read(i2c_base, adap->waitdelay, chip, addr,
738 				 alen, buffer, len);
739 }
740 
741 
742 static int omap24_i2c_write(struct i2c_adapter *adap, uchar chip, uint addr,
743 			    int alen, uchar *buffer, int len)
744 {
745 	struct i2c *i2c_base = omap24_get_base(adap);
746 
747 	return __omap24_i2c_write(i2c_base, adap->waitdelay, chip, addr,
748 				  alen, buffer, len);
749 }
750 
751 static uint omap24_i2c_setspeed(struct i2c_adapter *adap, uint speed)
752 {
753 	struct i2c *i2c_base = omap24_get_base(adap);
754 	int ret;
755 
756 	ret = __omap24_i2c_setspeed(i2c_base, speed, &adap->waitdelay);
757 	if (ret) {
758 		error("%s: set i2c speed failed\n", __func__);
759 		return ret;
760 	}
761 
762 	adap->speed = speed;
763 
764 	return 0;
765 }
766 
767 static void omap24_i2c_init(struct i2c_adapter *adap, int speed, int slaveadd)
768 {
769 	struct i2c *i2c_base = omap24_get_base(adap);
770 
771 	return __omap24_i2c_init(i2c_base, speed, slaveadd, &adap->waitdelay);
772 }
773 
774 static int omap24_i2c_probe(struct i2c_adapter *adap, uchar chip)
775 {
776 	struct i2c *i2c_base = omap24_get_base(adap);
777 
778 	return __omap24_i2c_probe(i2c_base, adap->waitdelay, chip);
779 }
780 
781 #if !defined(CONFIG_SYS_OMAP24_I2C_SPEED1)
782 #define CONFIG_SYS_OMAP24_I2C_SPEED1 CONFIG_SYS_OMAP24_I2C_SPEED
783 #endif
784 #if !defined(CONFIG_SYS_OMAP24_I2C_SLAVE1)
785 #define CONFIG_SYS_OMAP24_I2C_SLAVE1 CONFIG_SYS_OMAP24_I2C_SLAVE
786 #endif
787 
788 U_BOOT_I2C_ADAP_COMPLETE(omap24_0, omap24_i2c_init, omap24_i2c_probe,
789 			 omap24_i2c_read, omap24_i2c_write, omap24_i2c_setspeed,
790 			 CONFIG_SYS_OMAP24_I2C_SPEED,
791 			 CONFIG_SYS_OMAP24_I2C_SLAVE,
792 			 0)
793 U_BOOT_I2C_ADAP_COMPLETE(omap24_1, omap24_i2c_init, omap24_i2c_probe,
794 			 omap24_i2c_read, omap24_i2c_write, omap24_i2c_setspeed,
795 			 CONFIG_SYS_OMAP24_I2C_SPEED1,
796 			 CONFIG_SYS_OMAP24_I2C_SLAVE1,
797 			 1)
798 #if (I2C_BUS_MAX > 2)
799 #if !defined(CONFIG_SYS_OMAP24_I2C_SPEED2)
800 #define CONFIG_SYS_OMAP24_I2C_SPEED2 CONFIG_SYS_OMAP24_I2C_SPEED
801 #endif
802 #if !defined(CONFIG_SYS_OMAP24_I2C_SLAVE2)
803 #define CONFIG_SYS_OMAP24_I2C_SLAVE2 CONFIG_SYS_OMAP24_I2C_SLAVE
804 #endif
805 
806 U_BOOT_I2C_ADAP_COMPLETE(omap24_2, omap24_i2c_init, omap24_i2c_probe,
807 			 omap24_i2c_read, omap24_i2c_write, NULL,
808 			 CONFIG_SYS_OMAP24_I2C_SPEED2,
809 			 CONFIG_SYS_OMAP24_I2C_SLAVE2,
810 			 2)
811 #if (I2C_BUS_MAX > 3)
812 #if !defined(CONFIG_SYS_OMAP24_I2C_SPEED3)
813 #define CONFIG_SYS_OMAP24_I2C_SPEED3 CONFIG_SYS_OMAP24_I2C_SPEED
814 #endif
815 #if !defined(CONFIG_SYS_OMAP24_I2C_SLAVE3)
816 #define CONFIG_SYS_OMAP24_I2C_SLAVE3 CONFIG_SYS_OMAP24_I2C_SLAVE
817 #endif
818 
819 U_BOOT_I2C_ADAP_COMPLETE(omap24_3, omap24_i2c_init, omap24_i2c_probe,
820 			 omap24_i2c_read, omap24_i2c_write, NULL,
821 			 CONFIG_SYS_OMAP24_I2C_SPEED3,
822 			 CONFIG_SYS_OMAP24_I2C_SLAVE3,
823 			 3)
824 #if (I2C_BUS_MAX > 4)
825 #if !defined(CONFIG_SYS_OMAP24_I2C_SPEED4)
826 #define CONFIG_SYS_OMAP24_I2C_SPEED4 CONFIG_SYS_OMAP24_I2C_SPEED
827 #endif
828 #if !defined(CONFIG_SYS_OMAP24_I2C_SLAVE4)
829 #define CONFIG_SYS_OMAP24_I2C_SLAVE4 CONFIG_SYS_OMAP24_I2C_SLAVE
830 #endif
831 
832 U_BOOT_I2C_ADAP_COMPLETE(omap24_4, omap24_i2c_init, omap24_i2c_probe,
833 			 omap24_i2c_read, omap24_i2c_write, NULL,
834 			 CONFIG_SYS_OMAP24_I2C_SPEED4,
835 			 CONFIG_SYS_OMAP24_I2C_SLAVE4,
836 			 4)
837 #endif
838 #endif
839 #endif
840 
841 #else /* CONFIG_DM_I2C */
842 
843 static int omap_i2c_xfer(struct udevice *bus, struct i2c_msg *msg, int nmsgs)
844 {
845 	struct omap_i2c *priv = dev_get_priv(bus);
846 	int ret;
847 
848 	debug("i2c_xfer: %d messages\n", nmsgs);
849 	for (; nmsgs > 0; nmsgs--, msg++) {
850 		debug("i2c_xfer: chip=0x%x, len=0x%x\n", msg->addr, msg->len);
851 		if (msg->flags & I2C_M_RD) {
852 			ret = __omap24_i2c_read(priv->regs, priv->waitdelay,
853 						msg->addr, 0, 0, msg->buf,
854 						msg->len);
855 		} else {
856 			ret = __omap24_i2c_write(priv->regs, priv->waitdelay,
857 						 msg->addr, 0, 0, msg->buf,
858 						 msg->len);
859 		}
860 		if (ret) {
861 			debug("i2c_write: error sending\n");
862 			return -EREMOTEIO;
863 		}
864 	}
865 
866 	return 0;
867 }
868 
869 static int omap_i2c_set_bus_speed(struct udevice *bus, unsigned int speed)
870 {
871 	struct omap_i2c *priv = dev_get_priv(bus);
872 
873 	priv->speed = speed;
874 
875 	return __omap24_i2c_setspeed(priv->regs, speed, &priv->waitdelay);
876 }
877 
878 static int omap_i2c_probe_chip(struct udevice *bus, uint chip_addr,
879 				     uint chip_flags)
880 {
881 	struct omap_i2c *priv = dev_get_priv(bus);
882 
883 	return __omap24_i2c_probe(priv->regs, priv->waitdelay, chip_addr);
884 }
885 
886 static int omap_i2c_probe(struct udevice *bus)
887 {
888 	struct omap_i2c *priv = dev_get_priv(bus);
889 
890 	__omap24_i2c_init(priv->regs, priv->speed, 0, &priv->waitdelay);
891 
892 	return 0;
893 }
894 
895 static int omap_i2c_ofdata_to_platdata(struct udevice *bus)
896 {
897 	struct omap_i2c *priv = dev_get_priv(bus);
898 
899 	priv->regs = map_physmem(dev_get_addr(bus), sizeof(void *),
900 				 MAP_NOCACHE);
901 	priv->speed = CONFIG_SYS_OMAP24_I2C_SPEED;
902 
903 	return 0;
904 }
905 
906 static const struct dm_i2c_ops omap_i2c_ops = {
907 	.xfer		= omap_i2c_xfer,
908 	.probe_chip	= omap_i2c_probe_chip,
909 	.set_bus_speed	= omap_i2c_set_bus_speed,
910 };
911 
912 static const struct udevice_id omap_i2c_ids[] = {
913 	{ .compatible = "ti,omap3-i2c" },
914 	{ .compatible = "ti,omap4-i2c" },
915 	{ }
916 };
917 
918 U_BOOT_DRIVER(i2c_omap) = {
919 	.name	= "i2c_omap",
920 	.id	= UCLASS_I2C,
921 	.of_match = omap_i2c_ids,
922 	.ofdata_to_platdata = omap_i2c_ofdata_to_platdata,
923 	.probe	= omap_i2c_probe,
924 	.priv_auto_alloc_size = sizeof(struct omap_i2c),
925 	.ops	= &omap_i2c_ops,
926 	.flags  = DM_FLAG_PRE_RELOC,
927 };
928 
929 #endif /* CONFIG_DM_I2C */
930