xref: /openbmc/u-boot/drivers/i2c/mv_i2c.c (revision a381bcf5) 
1 /*
2  * (C) Copyright 2000
3  * Paolo Scaffardi, AIRVENT SAM s.p.a - RIMINI(ITALY), arsenio@tin.it
4  *
5  * (C) Copyright 2000 Sysgo Real-Time Solutions, GmbH <www.elinos.com>
6  * Marius Groeger <mgroeger@sysgo.de>
7  *
8  * (C) Copyright 2003 Pengutronix e.K.
9  * Robert Schwebel <r.schwebel@pengutronix.de>
10  *
11  * (C) Copyright 2011 Marvell Inc.
12  * Lei Wen <leiwen@marvell.com>
13  *
14  * SPDX-License-Identifier:	GPL-2.0+
15  *
16  * Back ported to the 8xx platform (from the 8260 platform) by
17  * Murray.Jensen@cmst.csiro.au, 27-Jan-01.
18  */
19 
20 #include <common.h>
21 #include <asm/io.h>
22 
23 #ifdef CONFIG_HARD_I2C
24 #include <i2c.h>
25 #include "mv_i2c.h"
26 
27 #ifdef DEBUG_I2C
28 #define PRINTD(x) printf x
29 #else
30 #define PRINTD(x)
31 #endif
32 
33 /* All transfers are described by this data structure */
34 struct mv_i2c_msg {
35 	u8 condition;
36 	u8 acknack;
37 	u8 direction;
38 	u8 data;
39 };
40 
41 struct mv_i2c {
42 	u32 ibmr;
43 	u32 pad0;
44 	u32 idbr;
45 	u32 pad1;
46 	u32 icr;
47 	u32 pad2;
48 	u32 isr;
49 	u32 pad3;
50 	u32 isar;
51 };
52 
53 static struct mv_i2c *base;
54 static void i2c_board_init(struct mv_i2c *base)
55 {
56 #ifdef CONFIG_SYS_I2C_INIT_BOARD
57 	u32 icr;
58 	/*
59 	 * call board specific i2c bus reset routine before accessing the
60 	 * environment, which might be in a chip on that bus. For details
61 	 * about this problem see doc/I2C_Edge_Conditions.
62 	 *
63 	 * disable I2C controller first, otherwhise it thinks we want to
64 	 * talk to the slave port...
65 	 */
66 	icr = readl(&base->icr);
67 	writel(readl(&base->icr) & ~(ICR_SCLE | ICR_IUE), &base->icr);
68 
69 	i2c_init_board();
70 
71 	writel(icr, &base->icr);
72 #endif
73 }
74 
75 #ifdef CONFIG_I2C_MULTI_BUS
76 static unsigned long i2c_regs[CONFIG_MV_I2C_NUM] = CONFIG_MV_I2C_REG;
77 static unsigned int bus_initialized[CONFIG_MV_I2C_NUM];
78 static unsigned int current_bus;
79 
80 int i2c_set_bus_num(unsigned int bus)
81 {
82 	if ((bus < 0) || (bus >= CONFIG_MV_I2C_NUM)) {
83 		printf("Bad bus: %d\n", bus);
84 		return -1;
85 	}
86 
87 	base = (struct mv_i2c *)i2c_regs[bus];
88 	current_bus = bus;
89 
90 	if (!bus_initialized[current_bus]) {
91 		i2c_board_init(base);
92 		bus_initialized[current_bus] = 1;
93 	}
94 
95 	return 0;
96 }
97 
98 unsigned int i2c_get_bus_num(void)
99 {
100 	return current_bus;
101 }
102 #endif
103 
104 /*
105  * i2c_reset: - reset the host controller
106  *
107  */
108 static void i2c_reset(void)
109 {
110 	writel(readl(&base->icr) & ~ICR_IUE, &base->icr); /* disable unit */
111 	writel(readl(&base->icr) | ICR_UR, &base->icr);	  /* reset the unit */
112 	udelay(100);
113 	writel(readl(&base->icr) & ~ICR_IUE, &base->icr); /* disable unit */
114 
115 	i2c_clk_enable();
116 
117 	writel(CONFIG_SYS_I2C_SLAVE, &base->isar); /* set our slave address */
118 	writel(I2C_ICR_INIT, &base->icr); /* set control reg values */
119 	writel(I2C_ISR_INIT, &base->isr); /* set clear interrupt bits */
120 	writel(readl(&base->icr) | ICR_IUE, &base->icr); /* enable unit */
121 	udelay(100);
122 }
123 
124 /*
125  * i2c_isr_set_cleared: - wait until certain bits of the I2C status register
126  *	                  are set and cleared
127  *
128  * @return: 1 in case of success, 0 means timeout (no match within 10 ms).
129  */
130 static int i2c_isr_set_cleared(unsigned long set_mask,
131 			       unsigned long cleared_mask)
132 {
133 	int timeout = 1000, isr;
134 
135 	do {
136 		isr = readl(&base->isr);
137 		udelay(10);
138 		if (timeout-- < 0)
139 			return 0;
140 	} while (((isr & set_mask) != set_mask)
141 		|| ((isr & cleared_mask) != 0));
142 
143 	return 1;
144 }
145 
146 /*
147  * i2c_transfer: - Transfer one byte over the i2c bus
148  *
149  * This function can tranfer a byte over the i2c bus in both directions.
150  * It is used by the public API functions.
151  *
152  * @return:  0: transfer successful
153  *          -1: message is empty
154  *          -2: transmit timeout
155  *          -3: ACK missing
156  *          -4: receive timeout
157  *          -5: illegal parameters
158  *          -6: bus is busy and couldn't be aquired
159  */
160 int i2c_transfer(struct mv_i2c_msg *msg)
161 {
162 	int ret;
163 
164 	if (!msg)
165 		goto transfer_error_msg_empty;
166 
167 	switch (msg->direction) {
168 	case I2C_WRITE:
169 		/* check if bus is not busy */
170 		if (!i2c_isr_set_cleared(0, ISR_IBB))
171 			goto transfer_error_bus_busy;
172 
173 		/* start transmission */
174 		writel(readl(&base->icr) & ~ICR_START, &base->icr);
175 		writel(readl(&base->icr) & ~ICR_STOP, &base->icr);
176 		writel(msg->data, &base->idbr);
177 		if (msg->condition == I2C_COND_START)
178 			writel(readl(&base->icr) | ICR_START, &base->icr);
179 		if (msg->condition == I2C_COND_STOP)
180 			writel(readl(&base->icr) | ICR_STOP, &base->icr);
181 		if (msg->acknack == I2C_ACKNAK_SENDNAK)
182 			writel(readl(&base->icr) | ICR_ACKNAK, &base->icr);
183 		if (msg->acknack == I2C_ACKNAK_SENDACK)
184 			writel(readl(&base->icr) & ~ICR_ACKNAK, &base->icr);
185 		writel(readl(&base->icr) & ~ICR_ALDIE, &base->icr);
186 		writel(readl(&base->icr) | ICR_TB, &base->icr);
187 
188 		/* transmit register empty? */
189 		if (!i2c_isr_set_cleared(ISR_ITE, 0))
190 			goto transfer_error_transmit_timeout;
191 
192 		/* clear 'transmit empty' state */
193 		writel(readl(&base->isr) | ISR_ITE, &base->isr);
194 
195 		/* wait for ACK from slave */
196 		if (msg->acknack == I2C_ACKNAK_WAITACK)
197 			if (!i2c_isr_set_cleared(0, ISR_ACKNAK))
198 				goto transfer_error_ack_missing;
199 		break;
200 
201 	case I2C_READ:
202 
203 		/* check if bus is not busy */
204 		if (!i2c_isr_set_cleared(0, ISR_IBB))
205 			goto transfer_error_bus_busy;
206 
207 		/* start receive */
208 		writel(readl(&base->icr) & ~ICR_START, &base->icr);
209 		writel(readl(&base->icr) & ~ICR_STOP, &base->icr);
210 		if (msg->condition == I2C_COND_START)
211 			writel(readl(&base->icr) | ICR_START, &base->icr);
212 		if (msg->condition == I2C_COND_STOP)
213 			writel(readl(&base->icr) | ICR_STOP, &base->icr);
214 		if (msg->acknack == I2C_ACKNAK_SENDNAK)
215 			writel(readl(&base->icr) | ICR_ACKNAK, &base->icr);
216 		if (msg->acknack == I2C_ACKNAK_SENDACK)
217 			writel(readl(&base->icr) & ~ICR_ACKNAK, &base->icr);
218 		writel(readl(&base->icr) & ~ICR_ALDIE, &base->icr);
219 		writel(readl(&base->icr) | ICR_TB, &base->icr);
220 
221 		/* receive register full? */
222 		if (!i2c_isr_set_cleared(ISR_IRF, 0))
223 			goto transfer_error_receive_timeout;
224 
225 		msg->data = readl(&base->idbr);
226 
227 		/* clear 'receive empty' state */
228 		writel(readl(&base->isr) | ISR_IRF, &base->isr);
229 		break;
230 	default:
231 		goto transfer_error_illegal_param;
232 	}
233 
234 	return 0;
235 
236 transfer_error_msg_empty:
237 		PRINTD(("i2c_transfer: error: 'msg' is empty\n"));
238 		ret = -1; goto i2c_transfer_finish;
239 
240 transfer_error_transmit_timeout:
241 		PRINTD(("i2c_transfer: error: transmit timeout\n"));
242 		ret = -2; goto i2c_transfer_finish;
243 
244 transfer_error_ack_missing:
245 		PRINTD(("i2c_transfer: error: ACK missing\n"));
246 		ret = -3; goto i2c_transfer_finish;
247 
248 transfer_error_receive_timeout:
249 		PRINTD(("i2c_transfer: error: receive timeout\n"));
250 		ret = -4; goto i2c_transfer_finish;
251 
252 transfer_error_illegal_param:
253 		PRINTD(("i2c_transfer: error: illegal parameters\n"));
254 		ret = -5; goto i2c_transfer_finish;
255 
256 transfer_error_bus_busy:
257 		PRINTD(("i2c_transfer: error: bus is busy\n"));
258 		ret = -6; goto i2c_transfer_finish;
259 
260 i2c_transfer_finish:
261 		PRINTD(("i2c_transfer: ISR: 0x%04x\n", readl(&base->isr)));
262 		i2c_reset();
263 		return ret;
264 }
265 
266 /* ------------------------------------------------------------------------ */
267 /* API Functions                                                            */
268 /* ------------------------------------------------------------------------ */
269 void i2c_init(int speed, int slaveaddr)
270 {
271 #ifdef CONFIG_I2C_MULTI_BUS
272 	current_bus = 0;
273 	base = (struct mv_i2c *)i2c_regs[current_bus];
274 #else
275 	base = (struct mv_i2c *)CONFIG_MV_I2C_REG;
276 #endif
277 
278 	i2c_board_init(base);
279 }
280 
281 /*
282  * i2c_probe: - Test if a chip answers for a given i2c address
283  *
284  * @chip:	address of the chip which is searched for
285  * @return:	0 if a chip was found, -1 otherwhise
286  */
287 int i2c_probe(uchar chip)
288 {
289 	struct mv_i2c_msg msg;
290 
291 	i2c_reset();
292 
293 	msg.condition = I2C_COND_START;
294 	msg.acknack   = I2C_ACKNAK_WAITACK;
295 	msg.direction = I2C_WRITE;
296 	msg.data      = (chip << 1) + 1;
297 	if (i2c_transfer(&msg))
298 		return -1;
299 
300 	msg.condition = I2C_COND_STOP;
301 	msg.acknack   = I2C_ACKNAK_SENDNAK;
302 	msg.direction = I2C_READ;
303 	msg.data      = 0x00;
304 	if (i2c_transfer(&msg))
305 		return -1;
306 
307 	return 0;
308 }
309 
310 /*
311  * i2c_read: - Read multiple bytes from an i2c device
312  *
313  * The higher level routines take into account that this function is only
314  * called with len < page length of the device (see configuration file)
315  *
316  * @chip:	address of the chip which is to be read
317  * @addr:	i2c data address within the chip
318  * @alen:	length of the i2c data address (1..2 bytes)
319  * @buffer:	where to write the data
320  * @len:	how much byte do we want to read
321  * @return:	0 in case of success
322  */
323 int i2c_read(uchar chip, uint addr, int alen, uchar *buffer, int len)
324 {
325 	struct mv_i2c_msg msg;
326 	u8 addr_bytes[3]; /* lowest...highest byte of data address */
327 
328 	PRINTD(("i2c_read(chip=0x%02x, addr=0x%02x, alen=0x%02x, "
329 		"len=0x%02x)\n", chip, addr, alen, len));
330 
331 	i2c_reset();
332 
333 	/* dummy chip address write */
334 	PRINTD(("i2c_read: dummy chip address write\n"));
335 	msg.condition = I2C_COND_START;
336 	msg.acknack   = I2C_ACKNAK_WAITACK;
337 	msg.direction = I2C_WRITE;
338 	msg.data = (chip << 1);
339 	msg.data &= 0xFE;
340 	if (i2c_transfer(&msg))
341 		return -1;
342 
343 	/*
344 	 * send memory address bytes;
345 	 * alen defines how much bytes we have to send.
346 	 */
347 	/*addr &= ((1 << CONFIG_SYS_EEPROM_PAGE_WRITE_BITS)-1); */
348 	addr_bytes[0] = (u8)((addr >>  0) & 0x000000FF);
349 	addr_bytes[1] = (u8)((addr >>  8) & 0x000000FF);
350 	addr_bytes[2] = (u8)((addr >> 16) & 0x000000FF);
351 
352 	while (--alen >= 0) {
353 		PRINTD(("i2c_read: send memory word address byte %1d\n", alen));
354 		msg.condition = I2C_COND_NORMAL;
355 		msg.acknack   = I2C_ACKNAK_WAITACK;
356 		msg.direction = I2C_WRITE;
357 		msg.data      = addr_bytes[alen];
358 		if (i2c_transfer(&msg))
359 			return -1;
360 	}
361 
362 	/* start read sequence */
363 	PRINTD(("i2c_read: start read sequence\n"));
364 	msg.condition = I2C_COND_START;
365 	msg.acknack   = I2C_ACKNAK_WAITACK;
366 	msg.direction = I2C_WRITE;
367 	msg.data      = (chip << 1);
368 	msg.data     |= 0x01;
369 	if (i2c_transfer(&msg))
370 		return -1;
371 
372 	/* read bytes; send NACK at last byte */
373 	while (len--) {
374 		if (len == 0) {
375 			msg.condition = I2C_COND_STOP;
376 			msg.acknack   = I2C_ACKNAK_SENDNAK;
377 		} else {
378 			msg.condition = I2C_COND_NORMAL;
379 			msg.acknack   = I2C_ACKNAK_SENDACK;
380 		}
381 
382 		msg.direction = I2C_READ;
383 		msg.data      = 0x00;
384 		if (i2c_transfer(&msg))
385 			return -1;
386 
387 		*buffer = msg.data;
388 		PRINTD(("i2c_read: reading byte (0x%08x)=0x%02x\n",
389 			(unsigned int)buffer, *buffer));
390 		buffer++;
391 	}
392 
393 	i2c_reset();
394 
395 	return 0;
396 }
397 
398 /*
399  * i2c_write: -  Write multiple bytes to an i2c device
400  *
401  * The higher level routines take into account that this function is only
402  * called with len < page length of the device (see configuration file)
403  *
404  * @chip:	address of the chip which is to be written
405  * @addr:	i2c data address within the chip
406  * @alen:	length of the i2c data address (1..2 bytes)
407  * @buffer:	where to find the data to be written
408  * @len:	how much byte do we want to read
409  * @return:	0 in case of success
410  */
411 int i2c_write(uchar chip, uint addr, int alen, uchar *buffer, int len)
412 {
413 	struct mv_i2c_msg msg;
414 	u8 addr_bytes[3]; /* lowest...highest byte of data address */
415 
416 	PRINTD(("i2c_write(chip=0x%02x, addr=0x%02x, alen=0x%02x, "
417 		"len=0x%02x)\n", chip, addr, alen, len));
418 
419 	i2c_reset();
420 
421 	/* chip address write */
422 	PRINTD(("i2c_write: chip address write\n"));
423 	msg.condition = I2C_COND_START;
424 	msg.acknack   = I2C_ACKNAK_WAITACK;
425 	msg.direction = I2C_WRITE;
426 	msg.data = (chip << 1);
427 	msg.data &= 0xFE;
428 	if (i2c_transfer(&msg))
429 		return -1;
430 
431 	/*
432 	 * send memory address bytes;
433 	 * alen defines how much bytes we have to send.
434 	 */
435 	addr_bytes[0] = (u8)((addr >>  0) & 0x000000FF);
436 	addr_bytes[1] = (u8)((addr >>  8) & 0x000000FF);
437 	addr_bytes[2] = (u8)((addr >> 16) & 0x000000FF);
438 
439 	while (--alen >= 0) {
440 		PRINTD(("i2c_write: send memory word address\n"));
441 		msg.condition = I2C_COND_NORMAL;
442 		msg.acknack   = I2C_ACKNAK_WAITACK;
443 		msg.direction = I2C_WRITE;
444 		msg.data      = addr_bytes[alen];
445 		if (i2c_transfer(&msg))
446 			return -1;
447 	}
448 
449 	/* write bytes; send NACK at last byte */
450 	while (len--) {
451 		PRINTD(("i2c_write: writing byte (0x%08x)=0x%02x\n",
452 			(unsigned int)buffer, *buffer));
453 
454 		if (len == 0)
455 			msg.condition = I2C_COND_STOP;
456 		else
457 			msg.condition = I2C_COND_NORMAL;
458 
459 		msg.acknack   = I2C_ACKNAK_WAITACK;
460 		msg.direction = I2C_WRITE;
461 		msg.data      = *(buffer++);
462 
463 		if (i2c_transfer(&msg))
464 			return -1;
465 	}
466 
467 	i2c_reset();
468 
469 	return 0;
470 }
471 #endif	/* CONFIG_HARD_I2C */
472