xref: /openbmc/u-boot/drivers/i2c/kona_i2c.c (revision 8ee59472)
1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * Copyright 2013 Broadcom Corporation.
4  *
5  * NOTE: This driver should be converted to driver model before June 2017.
6  * Please see doc/driver-model/i2c-howto.txt for instructions.
7  */
8 
9 #include <common.h>
10 #include <asm/io.h>
11 #include <linux/errno.h>
12 #include <asm/arch/sysmap.h>
13 #include <asm/kona-common/clk.h>
14 #include <i2c.h>
15 
16 /* Hardware register offsets and field defintions */
17 #define CS_OFFSET				0x00000020
18 #define CS_ACK_SHIFT				3
19 #define CS_ACK_MASK				0x00000008
20 #define CS_ACK_CMD_GEN_START			0x00000000
21 #define CS_ACK_CMD_GEN_RESTART			0x00000001
22 #define CS_CMD_SHIFT				1
23 #define CS_CMD_CMD_NO_ACTION			0x00000000
24 #define CS_CMD_CMD_START_RESTART		0x00000001
25 #define CS_CMD_CMD_STOP				0x00000002
26 #define CS_EN_SHIFT				0
27 #define CS_EN_CMD_ENABLE_BSC			0x00000001
28 
29 #define TIM_OFFSET				0x00000024
30 #define TIM_PRESCALE_SHIFT			6
31 #define TIM_P_SHIFT				3
32 #define TIM_NO_DIV_SHIFT			2
33 #define TIM_DIV_SHIFT				0
34 
35 #define DAT_OFFSET				0x00000028
36 
37 #define TOUT_OFFSET				0x0000002c
38 
39 #define TXFCR_OFFSET				0x0000003c
40 #define TXFCR_FIFO_FLUSH_MASK			0x00000080
41 #define TXFCR_FIFO_EN_MASK			0x00000040
42 
43 #define IER_OFFSET				0x00000044
44 #define IER_READ_COMPLETE_INT_MASK		0x00000010
45 #define IER_I2C_INT_EN_MASK			0x00000008
46 #define IER_FIFO_INT_EN_MASK			0x00000002
47 #define IER_NOACK_EN_MASK			0x00000001
48 
49 #define ISR_OFFSET				0x00000048
50 #define ISR_RESERVED_MASK			0xffffff60
51 #define ISR_CMDBUSY_MASK			0x00000080
52 #define ISR_READ_COMPLETE_MASK			0x00000010
53 #define ISR_SES_DONE_MASK			0x00000008
54 #define ISR_ERR_MASK				0x00000004
55 #define ISR_TXFIFOEMPTY_MASK			0x00000002
56 #define ISR_NOACK_MASK				0x00000001
57 
58 #define CLKEN_OFFSET				0x0000004c
59 #define CLKEN_AUTOSENSE_OFF_MASK		0x00000080
60 #define CLKEN_M_SHIFT				4
61 #define CLKEN_N_SHIFT				1
62 #define CLKEN_CLKEN_MASK			0x00000001
63 
64 #define FIFO_STATUS_OFFSET			0x00000054
65 #define FIFO_STATUS_RXFIFO_EMPTY_MASK		0x00000004
66 #define FIFO_STATUS_TXFIFO_EMPTY_MASK		0x00000010
67 
68 #define HSTIM_OFFSET				0x00000058
69 #define HSTIM_HS_MODE_MASK			0x00008000
70 #define HSTIM_HS_HOLD_SHIFT			10
71 #define HSTIM_HS_HIGH_PHASE_SHIFT		5
72 #define HSTIM_HS_SETUP_SHIFT			0
73 
74 #define PADCTL_OFFSET				0x0000005c
75 #define PADCTL_PAD_OUT_EN_MASK			0x00000004
76 
77 #define RXFCR_OFFSET				0x00000068
78 #define RXFCR_NACK_EN_SHIFT			7
79 #define RXFCR_READ_COUNT_SHIFT			0
80 #define RXFIFORDOUT_OFFSET			0x0000006c
81 
82 /* Locally used constants */
83 #define MAX_RX_FIFO_SIZE		64U	/* bytes */
84 #define MAX_TX_FIFO_SIZE		64U	/* bytes */
85 
86 #define I2C_TIMEOUT			100000	/* usecs */
87 
88 #define WAIT_INT_CHK			100	/* usecs */
89 #if I2C_TIMEOUT % WAIT_INT_CHK
90 #error I2C_TIMEOUT must be a multiple of WAIT_INT_CHK
91 #endif
92 
93 /* Operations that can be commanded to the controller */
94 enum bcm_kona_cmd_t {
95 	BCM_CMD_NOACTION = 0,
96 	BCM_CMD_START,
97 	BCM_CMD_RESTART,
98 	BCM_CMD_STOP,
99 };
100 
101 enum bus_speed_index {
102 	BCM_SPD_100K = 0,
103 	BCM_SPD_400K,
104 	BCM_SPD_1MHZ,
105 };
106 
107 /* Internal divider settings for standard mode, fast mode and fast mode plus */
108 struct bus_speed_cfg {
109 	uint8_t time_m;		/* Number of cycles for setup time */
110 	uint8_t time_n;		/* Number of cycles for hold time */
111 	uint8_t prescale;	/* Prescale divider */
112 	uint8_t time_p;		/* Timing coefficient */
113 	uint8_t no_div;		/* Disable clock divider */
114 	uint8_t time_div;	/* Post-prescale divider */
115 };
116 
117 static const struct bus_speed_cfg std_cfg_table[] = {
118 	[BCM_SPD_100K] = {0x01, 0x01, 0x03, 0x06, 0x00, 0x02},
119 	[BCM_SPD_400K] = {0x05, 0x01, 0x03, 0x05, 0x01, 0x02},
120 	[BCM_SPD_1MHZ] = {0x01, 0x01, 0x03, 0x01, 0x01, 0x03},
121 };
122 
123 struct bcm_kona_i2c_dev {
124 	void *base;
125 	uint speed;
126 	const struct bus_speed_cfg *std_cfg;
127 };
128 
129 /* Keep these two defines in sync */
130 #define DEF_SPD 100000
131 #define DEF_SPD_ENUM BCM_SPD_100K
132 
133 #define DEF_DEVICE(num) \
134 {(void *)CONFIG_SYS_I2C_BASE##num, DEF_SPD, &std_cfg_table[DEF_SPD_ENUM]}
135 
136 static struct bcm_kona_i2c_dev g_i2c_devs[CONFIG_SYS_MAX_I2C_BUS] = {
137 #ifdef CONFIG_SYS_I2C_BASE0
138 	DEF_DEVICE(0),
139 #endif
140 #ifdef CONFIG_SYS_I2C_BASE1
141 	DEF_DEVICE(1),
142 #endif
143 #ifdef CONFIG_SYS_I2C_BASE2
144 	DEF_DEVICE(2),
145 #endif
146 #ifdef CONFIG_SYS_I2C_BASE3
147 	DEF_DEVICE(3),
148 #endif
149 #ifdef CONFIG_SYS_I2C_BASE4
150 	DEF_DEVICE(4),
151 #endif
152 #ifdef CONFIG_SYS_I2C_BASE5
153 	DEF_DEVICE(5),
154 #endif
155 };
156 
157 #define I2C_M_TEN	0x0010	/* ten bit address */
158 #define I2C_M_RD	0x0001	/* read data */
159 #define I2C_M_NOSTART	0x4000	/* no restart between msgs */
160 
161 struct kona_i2c_msg {
162 	uint16_t addr;
163 	uint16_t flags;
164 	uint16_t len;
165 	uint8_t *buf;
166 };
167 
168 static void bcm_kona_i2c_send_cmd_to_ctrl(struct bcm_kona_i2c_dev *dev,
169 					  enum bcm_kona_cmd_t cmd)
170 {
171 	debug("%s, %d\n", __func__, cmd);
172 
173 	switch (cmd) {
174 	case BCM_CMD_NOACTION:
175 		writel((CS_CMD_CMD_NO_ACTION << CS_CMD_SHIFT) |
176 		       (CS_EN_CMD_ENABLE_BSC << CS_EN_SHIFT),
177 		       dev->base + CS_OFFSET);
178 		break;
179 
180 	case BCM_CMD_START:
181 		writel((CS_ACK_CMD_GEN_START << CS_ACK_SHIFT) |
182 		       (CS_CMD_CMD_START_RESTART << CS_CMD_SHIFT) |
183 		       (CS_EN_CMD_ENABLE_BSC << CS_EN_SHIFT),
184 		       dev->base + CS_OFFSET);
185 		break;
186 
187 	case BCM_CMD_RESTART:
188 		writel((CS_ACK_CMD_GEN_RESTART << CS_ACK_SHIFT) |
189 		       (CS_CMD_CMD_START_RESTART << CS_CMD_SHIFT) |
190 		       (CS_EN_CMD_ENABLE_BSC << CS_EN_SHIFT),
191 		       dev->base + CS_OFFSET);
192 		break;
193 
194 	case BCM_CMD_STOP:
195 		writel((CS_CMD_CMD_STOP << CS_CMD_SHIFT) |
196 		       (CS_EN_CMD_ENABLE_BSC << CS_EN_SHIFT),
197 		       dev->base + CS_OFFSET);
198 		break;
199 
200 	default:
201 		printf("Unknown command %d\n", cmd);
202 	}
203 }
204 
205 static void bcm_kona_i2c_enable_clock(struct bcm_kona_i2c_dev *dev)
206 {
207 	writel(readl(dev->base + CLKEN_OFFSET) | CLKEN_CLKEN_MASK,
208 	       dev->base + CLKEN_OFFSET);
209 }
210 
211 static void bcm_kona_i2c_disable_clock(struct bcm_kona_i2c_dev *dev)
212 {
213 	writel(readl(dev->base + CLKEN_OFFSET) & ~CLKEN_CLKEN_MASK,
214 	       dev->base + CLKEN_OFFSET);
215 }
216 
217 /* Wait until at least one of the mask bit(s) are set */
218 static unsigned long wait_for_int_timeout(struct bcm_kona_i2c_dev *dev,
219 					  unsigned long time_left,
220 					  uint32_t mask)
221 {
222 	uint32_t status;
223 
224 	while (time_left) {
225 		status = readl(dev->base + ISR_OFFSET);
226 
227 		if ((status & ~ISR_RESERVED_MASK) == 0) {
228 			debug("Bogus I2C interrupt 0x%x\n", status);
229 			continue;
230 		}
231 
232 		/* Must flush the TX FIFO when NAK detected */
233 		if (status & ISR_NOACK_MASK)
234 			writel(TXFCR_FIFO_FLUSH_MASK | TXFCR_FIFO_EN_MASK,
235 			       dev->base + TXFCR_OFFSET);
236 
237 		writel(status & ~ISR_RESERVED_MASK, dev->base + ISR_OFFSET);
238 
239 		if (status & mask) {
240 			/* We are done since one of the mask bits are set */
241 			return time_left;
242 		}
243 		udelay(WAIT_INT_CHK);
244 		time_left -= WAIT_INT_CHK;
245 	}
246 	return 0;
247 }
248 
249 /* Send command to I2C bus */
250 static int bcm_kona_send_i2c_cmd(struct bcm_kona_i2c_dev *dev,
251 				 enum bcm_kona_cmd_t cmd)
252 {
253 	int rc = 0;
254 	unsigned long time_left = I2C_TIMEOUT;
255 
256 	/* Send the command */
257 	bcm_kona_i2c_send_cmd_to_ctrl(dev, cmd);
258 
259 	/* Wait for transaction to finish or timeout */
260 	time_left = wait_for_int_timeout(dev, time_left, IER_I2C_INT_EN_MASK);
261 
262 	if (!time_left) {
263 		printf("controller timed out\n");
264 		rc = -ETIMEDOUT;
265 	}
266 
267 	/* Clear command */
268 	bcm_kona_i2c_send_cmd_to_ctrl(dev, BCM_CMD_NOACTION);
269 
270 	return rc;
271 }
272 
273 /* Read a single RX FIFO worth of data from the i2c bus */
274 static int bcm_kona_i2c_read_fifo_single(struct bcm_kona_i2c_dev *dev,
275 					 uint8_t *buf, unsigned int len,
276 					 unsigned int last_byte_nak)
277 {
278 	unsigned long time_left = I2C_TIMEOUT;
279 
280 	/* Start the RX FIFO */
281 	writel((last_byte_nak << RXFCR_NACK_EN_SHIFT) |
282 	       (len << RXFCR_READ_COUNT_SHIFT), dev->base + RXFCR_OFFSET);
283 
284 	/* Wait for FIFO read to complete */
285 	time_left =
286 	    wait_for_int_timeout(dev, time_left, IER_READ_COMPLETE_INT_MASK);
287 
288 	if (!time_left) {
289 		printf("RX FIFO time out\n");
290 		return -EREMOTEIO;
291 	}
292 
293 	/* Read data from FIFO */
294 	for (; len > 0; len--, buf++)
295 		*buf = readl(dev->base + RXFIFORDOUT_OFFSET);
296 
297 	return 0;
298 }
299 
300 /* Read any amount of data using the RX FIFO from the i2c bus */
301 static int bcm_kona_i2c_read_fifo(struct bcm_kona_i2c_dev *dev,
302 				  struct kona_i2c_msg *msg)
303 {
304 	unsigned int bytes_to_read = MAX_RX_FIFO_SIZE;
305 	unsigned int last_byte_nak = 0;
306 	unsigned int bytes_read = 0;
307 	int rc;
308 
309 	uint8_t *tmp_buf = msg->buf;
310 
311 	while (bytes_read < msg->len) {
312 		if (msg->len - bytes_read <= MAX_RX_FIFO_SIZE) {
313 			last_byte_nak = 1;	/* NAK last byte of transfer */
314 			bytes_to_read = msg->len - bytes_read;
315 		}
316 
317 		rc = bcm_kona_i2c_read_fifo_single(dev, tmp_buf, bytes_to_read,
318 						   last_byte_nak);
319 		if (rc < 0)
320 			return -EREMOTEIO;
321 
322 		bytes_read += bytes_to_read;
323 		tmp_buf += bytes_to_read;
324 	}
325 
326 	return 0;
327 }
328 
329 /* Write a single byte of data to the i2c bus */
330 static int bcm_kona_i2c_write_byte(struct bcm_kona_i2c_dev *dev, uint8_t data,
331 				   unsigned int nak_expected)
332 {
333 	unsigned long time_left = I2C_TIMEOUT;
334 	unsigned int nak_received;
335 
336 	/* Clear pending session done interrupt */
337 	writel(ISR_SES_DONE_MASK, dev->base + ISR_OFFSET);
338 
339 	/* Send one byte of data */
340 	writel(data, dev->base + DAT_OFFSET);
341 
342 	time_left = wait_for_int_timeout(dev, time_left, IER_I2C_INT_EN_MASK);
343 
344 	if (!time_left) {
345 		debug("controller timed out\n");
346 		return -ETIMEDOUT;
347 	}
348 
349 	nak_received = readl(dev->base + CS_OFFSET) & CS_ACK_MASK ? 1 : 0;
350 
351 	if (nak_received ^ nak_expected) {
352 		debug("unexpected NAK/ACK\n");
353 		return -EREMOTEIO;
354 	}
355 
356 	return 0;
357 }
358 
359 /* Write a single TX FIFO worth of data to the i2c bus */
360 static int bcm_kona_i2c_write_fifo_single(struct bcm_kona_i2c_dev *dev,
361 					  uint8_t *buf, unsigned int len)
362 {
363 	int k;
364 	unsigned long time_left = I2C_TIMEOUT;
365 	unsigned int fifo_status;
366 
367 	/* Write data into FIFO */
368 	for (k = 0; k < len; k++)
369 		writel(buf[k], (dev->base + DAT_OFFSET));
370 
371 	/* Wait for FIFO to empty */
372 	do {
373 		time_left =
374 		    wait_for_int_timeout(dev, time_left,
375 					 (IER_FIFO_INT_EN_MASK |
376 					  IER_NOACK_EN_MASK));
377 		fifo_status = readl(dev->base + FIFO_STATUS_OFFSET);
378 	} while (time_left && !(fifo_status & FIFO_STATUS_TXFIFO_EMPTY_MASK));
379 
380 	/* Check if there was a NAK */
381 	if (readl(dev->base + CS_OFFSET) & CS_ACK_MASK) {
382 		printf("unexpected NAK\n");
383 		return -EREMOTEIO;
384 	}
385 
386 	/* Check if a timeout occurred */
387 	if (!time_left) {
388 		printf("completion timed out\n");
389 		return -EREMOTEIO;
390 	}
391 
392 	return 0;
393 }
394 
395 /* Write any amount of data using TX FIFO to the i2c bus */
396 static int bcm_kona_i2c_write_fifo(struct bcm_kona_i2c_dev *dev,
397 				   struct kona_i2c_msg *msg)
398 {
399 	unsigned int bytes_to_write = MAX_TX_FIFO_SIZE;
400 	unsigned int bytes_written = 0;
401 	int rc;
402 
403 	uint8_t *tmp_buf = msg->buf;
404 
405 	while (bytes_written < msg->len) {
406 		if (msg->len - bytes_written <= MAX_TX_FIFO_SIZE)
407 			bytes_to_write = msg->len - bytes_written;
408 
409 		rc = bcm_kona_i2c_write_fifo_single(dev, tmp_buf,
410 						    bytes_to_write);
411 		if (rc < 0)
412 			return -EREMOTEIO;
413 
414 		bytes_written += bytes_to_write;
415 		tmp_buf += bytes_to_write;
416 	}
417 
418 	return 0;
419 }
420 
421 /* Send i2c address */
422 static int bcm_kona_i2c_do_addr(struct bcm_kona_i2c_dev *dev,
423 				struct kona_i2c_msg *msg)
424 {
425 	unsigned char addr;
426 
427 	if (msg->flags & I2C_M_TEN) {
428 		/* First byte is 11110XX0 where XX is upper 2 bits */
429 		addr = 0xf0 | ((msg->addr & 0x300) >> 7);
430 		if (bcm_kona_i2c_write_byte(dev, addr, 0) < 0)
431 			return -EREMOTEIO;
432 
433 		/* Second byte is the remaining 8 bits */
434 		addr = msg->addr & 0xff;
435 		if (bcm_kona_i2c_write_byte(dev, addr, 0) < 0)
436 			return -EREMOTEIO;
437 
438 		if (msg->flags & I2C_M_RD) {
439 			/* For read, send restart command */
440 			if (bcm_kona_send_i2c_cmd(dev, BCM_CMD_RESTART) < 0)
441 				return -EREMOTEIO;
442 
443 			/* Then re-send the first byte with the read bit set */
444 			addr = 0xf0 | ((msg->addr & 0x300) >> 7) | 0x01;
445 			if (bcm_kona_i2c_write_byte(dev, addr, 0) < 0)
446 				return -EREMOTEIO;
447 		}
448 	} else {
449 		addr = msg->addr << 1;
450 
451 		if (msg->flags & I2C_M_RD)
452 			addr |= 1;
453 
454 		if (bcm_kona_i2c_write_byte(dev, addr, 0) < 0)
455 			return -EREMOTEIO;
456 	}
457 
458 	return 0;
459 }
460 
461 static void bcm_kona_i2c_enable_autosense(struct bcm_kona_i2c_dev *dev)
462 {
463 	writel(readl(dev->base + CLKEN_OFFSET) & ~CLKEN_AUTOSENSE_OFF_MASK,
464 	       dev->base + CLKEN_OFFSET);
465 }
466 
467 static void bcm_kona_i2c_config_timing(struct bcm_kona_i2c_dev *dev)
468 {
469 	writel(readl(dev->base + HSTIM_OFFSET) & ~HSTIM_HS_MODE_MASK,
470 	       dev->base + HSTIM_OFFSET);
471 
472 	writel((dev->std_cfg->prescale << TIM_PRESCALE_SHIFT) |
473 	       (dev->std_cfg->time_p << TIM_P_SHIFT) |
474 	       (dev->std_cfg->no_div << TIM_NO_DIV_SHIFT) |
475 	       (dev->std_cfg->time_div << TIM_DIV_SHIFT),
476 	       dev->base + TIM_OFFSET);
477 
478 	writel((dev->std_cfg->time_m << CLKEN_M_SHIFT) |
479 	       (dev->std_cfg->time_n << CLKEN_N_SHIFT) |
480 	       CLKEN_CLKEN_MASK, dev->base + CLKEN_OFFSET);
481 }
482 
483 /* Master transfer function */
484 static int bcm_kona_i2c_xfer(struct bcm_kona_i2c_dev *dev,
485 			     struct kona_i2c_msg msgs[], int num)
486 {
487 	struct kona_i2c_msg *pmsg;
488 	int rc = 0;
489 	int i;
490 
491 	/* Enable pad output */
492 	writel(0, dev->base + PADCTL_OFFSET);
493 
494 	/* Enable internal clocks */
495 	bcm_kona_i2c_enable_clock(dev);
496 
497 	/* Send start command */
498 	rc = bcm_kona_send_i2c_cmd(dev, BCM_CMD_START);
499 	if (rc < 0) {
500 		printf("Start command failed rc = %d\n", rc);
501 		goto xfer_disable_pad;
502 	}
503 
504 	/* Loop through all messages */
505 	for (i = 0; i < num; i++) {
506 		pmsg = &msgs[i];
507 
508 		/* Send restart for subsequent messages */
509 		if ((i != 0) && ((pmsg->flags & I2C_M_NOSTART) == 0)) {
510 			rc = bcm_kona_send_i2c_cmd(dev, BCM_CMD_RESTART);
511 			if (rc < 0) {
512 				printf("restart cmd failed rc = %d\n", rc);
513 				goto xfer_send_stop;
514 			}
515 		}
516 
517 		/* Send slave address */
518 		if (!(pmsg->flags & I2C_M_NOSTART)) {
519 			rc = bcm_kona_i2c_do_addr(dev, pmsg);
520 			if (rc < 0) {
521 				debug("NAK from addr %2.2x msg#%d rc = %d\n",
522 				      pmsg->addr, i, rc);
523 				goto xfer_send_stop;
524 			}
525 		}
526 
527 		/* Perform data transfer */
528 		if (pmsg->flags & I2C_M_RD) {
529 			rc = bcm_kona_i2c_read_fifo(dev, pmsg);
530 			if (rc < 0) {
531 				printf("read failure\n");
532 				goto xfer_send_stop;
533 			}
534 		} else {
535 			rc = bcm_kona_i2c_write_fifo(dev, pmsg);
536 			if (rc < 0) {
537 				printf("write failure");
538 				goto xfer_send_stop;
539 			}
540 		}
541 	}
542 
543 	rc = num;
544 
545 xfer_send_stop:
546 	/* Send a STOP command */
547 	bcm_kona_send_i2c_cmd(dev, BCM_CMD_STOP);
548 
549 xfer_disable_pad:
550 	/* Disable pad output */
551 	writel(PADCTL_PAD_OUT_EN_MASK, dev->base + PADCTL_OFFSET);
552 
553 	/* Stop internal clock */
554 	bcm_kona_i2c_disable_clock(dev);
555 
556 	return rc;
557 }
558 
559 static uint bcm_kona_i2c_assign_bus_speed(struct bcm_kona_i2c_dev *dev,
560 					  uint speed)
561 {
562 	switch (speed) {
563 	case 100000:
564 		dev->std_cfg = &std_cfg_table[BCM_SPD_100K];
565 		break;
566 	case 400000:
567 		dev->std_cfg = &std_cfg_table[BCM_SPD_400K];
568 		break;
569 	case 1000000:
570 		dev->std_cfg = &std_cfg_table[BCM_SPD_1MHZ];
571 		break;
572 	default:
573 		printf("%d hz bus speed not supported\n", speed);
574 		return -EINVAL;
575 	}
576 	dev->speed = speed;
577 	return 0;
578 }
579 
580 static void bcm_kona_i2c_init(struct bcm_kona_i2c_dev *dev)
581 {
582 	/* Parse bus speed */
583 	bcm_kona_i2c_assign_bus_speed(dev, dev->speed);
584 
585 	/* Enable internal clocks */
586 	bcm_kona_i2c_enable_clock(dev);
587 
588 	/* Configure internal dividers */
589 	bcm_kona_i2c_config_timing(dev);
590 
591 	/* Disable timeout */
592 	writel(0, dev->base + TOUT_OFFSET);
593 
594 	/* Enable autosense */
595 	bcm_kona_i2c_enable_autosense(dev);
596 
597 	/* Enable TX FIFO */
598 	writel(TXFCR_FIFO_FLUSH_MASK | TXFCR_FIFO_EN_MASK,
599 	       dev->base + TXFCR_OFFSET);
600 
601 	/* Mask all interrupts */
602 	writel(0, dev->base + IER_OFFSET);
603 
604 	/* Clear all pending interrupts */
605 	writel(ISR_CMDBUSY_MASK |
606 	       ISR_READ_COMPLETE_MASK |
607 	       ISR_SES_DONE_MASK |
608 	       ISR_ERR_MASK |
609 	       ISR_TXFIFOEMPTY_MASK | ISR_NOACK_MASK, dev->base + ISR_OFFSET);
610 
611 	/* Enable the controller but leave it idle */
612 	bcm_kona_i2c_send_cmd_to_ctrl(dev, BCM_CMD_NOACTION);
613 
614 	/* Disable pad output */
615 	writel(PADCTL_PAD_OUT_EN_MASK, dev->base + PADCTL_OFFSET);
616 }
617 
618 /*
619  * uboot layer
620  */
621 struct bcm_kona_i2c_dev *kona_get_dev(struct i2c_adapter *adap)
622 {
623 	return &g_i2c_devs[adap->hwadapnr];
624 }
625 
626 static void kona_i2c_init(struct i2c_adapter *adap, int speed, int slaveaddr)
627 {
628 	struct bcm_kona_i2c_dev *dev = kona_get_dev(adap);
629 
630 	if (clk_bsc_enable(dev->base))
631 		return;
632 
633 	bcm_kona_i2c_init(dev);
634 }
635 
636 static int kona_i2c_read(struct i2c_adapter *adap, uchar chip, uint addr,
637 			 int alen, uchar *buffer, int len)
638 {
639 	/* msg[0] writes the addr, msg[1] reads the data */
640 	struct kona_i2c_msg msg[2];
641 	unsigned char msgbuf0[64];
642 	struct bcm_kona_i2c_dev *dev = kona_get_dev(adap);
643 
644 	msg[0].addr = chip;
645 	msg[0].flags = 0;
646 	msg[0].len = 1;
647 	msg[0].buf = msgbuf0;	/* msgbuf0 contains incrementing reg addr */
648 
649 	msg[1].addr = chip;
650 	msg[1].flags = I2C_M_RD;
651 	/* msg[1].buf dest ptr increments each read */
652 
653 	msgbuf0[0] = (unsigned char)addr;
654 	msg[1].buf = buffer;
655 	msg[1].len = len;
656 	if (bcm_kona_i2c_xfer(dev, msg, 2) < 0) {
657 		/* Sending 2 i2c messages */
658 		kona_i2c_init(adap, adap->speed, adap->slaveaddr);
659 		debug("I2C read: I/O error\n");
660 		return -EIO;
661 	}
662 	return 0;
663 }
664 
665 static int kona_i2c_write(struct i2c_adapter *adap, uchar chip, uint addr,
666 			  int alen, uchar *buffer, int len)
667 {
668 	struct kona_i2c_msg msg[1];
669 	unsigned char msgbuf0[64];
670 	unsigned int i;
671 	struct bcm_kona_i2c_dev *dev = kona_get_dev(adap);
672 
673 	msg[0].addr = chip;
674 	msg[0].flags = 0;
675 	msg[0].len = 2;		/* addr byte plus data */
676 	msg[0].buf = msgbuf0;
677 
678 	for (i = 0; i < len; i++) {
679 		msgbuf0[0] = addr++;
680 		msgbuf0[1] = buffer[i];
681 		if (bcm_kona_i2c_xfer(dev, msg, 1) < 0) {
682 			kona_i2c_init(adap, adap->speed, adap->slaveaddr);
683 			debug("I2C write: I/O error\n");
684 			return -EIO;
685 		}
686 	}
687 	return 0;
688 }
689 
690 static int kona_i2c_probe(struct i2c_adapter *adap, uchar chip)
691 {
692 	uchar tmp;
693 
694 	/*
695 	 * read addr 0x0 of the given chip.
696 	 */
697 	return kona_i2c_read(adap, chip, 0x0, 1, &tmp, 1);
698 }
699 
700 static uint kona_i2c_set_bus_speed(struct i2c_adapter *adap, uint speed)
701 {
702 	struct bcm_kona_i2c_dev *dev = kona_get_dev(adap);
703 	return bcm_kona_i2c_assign_bus_speed(dev, speed);
704 }
705 
706 /*
707  * Register kona i2c adapters. Keep the order below so
708  * that the bus number matches the adapter number.
709  */
710 #define DEF_ADAPTER(num) \
711 U_BOOT_I2C_ADAP_COMPLETE(kona##num, kona_i2c_init, kona_i2c_probe, \
712 			 kona_i2c_read, kona_i2c_write, \
713 			 kona_i2c_set_bus_speed, DEF_SPD, 0x00, num)
714 
715 #ifdef CONFIG_SYS_I2C_BASE0
716 	DEF_ADAPTER(0)
717 #endif
718 #ifdef CONFIG_SYS_I2C_BASE1
719 	DEF_ADAPTER(1)
720 #endif
721 #ifdef CONFIG_SYS_I2C_BASE2
722 	DEF_ADAPTER(2)
723 #endif
724 #ifdef CONFIG_SYS_I2C_BASE3
725 	DEF_ADAPTER(3)
726 #endif
727 #ifdef CONFIG_SYS_I2C_BASE4
728 	DEF_ADAPTER(4)
729 #endif
730 #ifdef CONFIG_SYS_I2C_BASE5
731 	DEF_ADAPTER(5)
732 #endif
733