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wdenkc6097192002-11-03 00:24:07 +00001/*
2 * (C) Copyright 2001, 2002
3 * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
4 *
5 * See file CREDITS for list of people who contributed to this
6 * project.
7 *
8 * This program is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU General Public License as
10 * published by the Free Software Foundation; either version 2 of
11 * the License, or (at your option) any later version.
12 *
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
17 *
18 * You should have received a copy of the GNU General Public License
19 * along with this program; if not, write to the Free Software
20 * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
21 * MA 02111-1307 USA
22 *
23 * This has been changed substantially by Gerald Van Baren, Custom IDEAS,
24 * vanbaren@cideas.com. It was heavily influenced by LiMon, written by
25 * Neil Russell.
26 */
27
28#include <common.h>
29#ifdef CONFIG_MPC8260 /* only valid for MPC8260 */
30#include <ioports.h>
31#endif
Peter Pearsed4fc6012007-08-14 10:10:52 +010032#ifdef CONFIG_AT91RM9200 /* need this for the at91rm9200 */
wdenk9d5028c2004-11-21 00:06:33 +000033#include <asm/io.h>
34#include <asm/arch/hardware.h>
35#endif
Wolfgang Denkba94a1b2006-05-30 15:56:48 +020036#ifdef CONFIG_IXP425 /* only valid for IXP425 */
37#include <asm/arch/ixp425.h>
38#endif
Peter Pearseb0d8f5b2007-05-09 11:37:56 +010039#ifdef CONFIG_LPC2292
40#include <asm/arch/hardware.h>
41#endif
wdenkc6097192002-11-03 00:24:07 +000042#include <i2c.h>
43
44#if defined(CONFIG_SOFT_I2C)
45
46/* #define DEBUG_I2C */
47
Wolfgang Denkd87080b2006-03-31 18:32:53 +020048#ifdef DEBUG_I2C
49DECLARE_GLOBAL_DATA_PTR;
50#endif
51
wdenkc6097192002-11-03 00:24:07 +000052
53/*-----------------------------------------------------------------------
54 * Definitions
55 */
56
57#define RETRIES 0
58
59
60#define I2C_ACK 0 /* PD_SDA level to ack a byte */
61#define I2C_NOACK 1 /* PD_SDA level to noack a byte */
62
63
64#ifdef DEBUG_I2C
65#define PRINTD(fmt,args...) do { \
wdenkc6097192002-11-03 00:24:07 +000066 if (gd->have_console) \
67 printf (fmt ,##args); \
68 } while (0)
69#else
70#define PRINTD(fmt,args...)
71#endif
72
73/*-----------------------------------------------------------------------
74 * Local functions
75 */
76static void send_reset (void);
77static void send_start (void);
78static void send_stop (void);
79static void send_ack (int);
80static int write_byte (uchar byte);
81static uchar read_byte (int);
82
83
84/*-----------------------------------------------------------------------
85 * Send a reset sequence consisting of 9 clocks with the data signal high
86 * to clock any confused device back into an idle state. Also send a
87 * <stop> at the end of the sequence for belts & suspenders.
88 */
89static void send_reset(void)
90{
91#ifdef CONFIG_MPC8260
92 volatile ioport_t *iop = ioport_addr((immap_t *)CFG_IMMR, I2C_PORT);
93#endif
94#ifdef CONFIG_8xx
95 volatile immap_t *immr = (immap_t *)CFG_IMMR;
96#endif
97 int j;
98
wdenk60fbe252003-04-08 23:25:21 +000099 I2C_SCL(1);
wdenkc6097192002-11-03 00:24:07 +0000100 I2C_SDA(1);
wdenk60fbe252003-04-08 23:25:21 +0000101#ifdef I2C_INIT
102 I2C_INIT;
103#endif
104 I2C_TRISTATE;
wdenkc6097192002-11-03 00:24:07 +0000105 for(j = 0; j < 9; j++) {
106 I2C_SCL(0);
107 I2C_DELAY;
108 I2C_DELAY;
109 I2C_SCL(1);
110 I2C_DELAY;
111 I2C_DELAY;
112 }
113 send_stop();
114 I2C_TRISTATE;
115}
116
117/*-----------------------------------------------------------------------
118 * START: High -> Low on SDA while SCL is High
119 */
120static void send_start(void)
121{
122#ifdef CONFIG_MPC8260
123 volatile ioport_t *iop = ioport_addr((immap_t *)CFG_IMMR, I2C_PORT);
124#endif
125#ifdef CONFIG_8xx
126 volatile immap_t *immr = (immap_t *)CFG_IMMR;
127#endif
128
129 I2C_DELAY;
130 I2C_SDA(1);
131 I2C_ACTIVE;
132 I2C_DELAY;
133 I2C_SCL(1);
134 I2C_DELAY;
135 I2C_SDA(0);
136 I2C_DELAY;
137}
138
139/*-----------------------------------------------------------------------
140 * STOP: Low -> High on SDA while SCL is High
141 */
142static void send_stop(void)
143{
144#ifdef CONFIG_MPC8260
145 volatile ioport_t *iop = ioport_addr((immap_t *)CFG_IMMR, I2C_PORT);
146#endif
147#ifdef CONFIG_8xx
148 volatile immap_t *immr = (immap_t *)CFG_IMMR;
149#endif
150
151 I2C_SCL(0);
152 I2C_DELAY;
153 I2C_SDA(0);
154 I2C_ACTIVE;
155 I2C_DELAY;
156 I2C_SCL(1);
157 I2C_DELAY;
158 I2C_SDA(1);
159 I2C_DELAY;
160 I2C_TRISTATE;
161}
162
163
164/*-----------------------------------------------------------------------
165 * ack should be I2C_ACK or I2C_NOACK
166 */
167static void send_ack(int ack)
168{
169#ifdef CONFIG_MPC8260
170 volatile ioport_t *iop = ioport_addr((immap_t *)CFG_IMMR, I2C_PORT);
171#endif
172#ifdef CONFIG_8xx
173 volatile immap_t *immr = (immap_t *)CFG_IMMR;
174#endif
175
wdenkc6097192002-11-03 00:24:07 +0000176 I2C_SCL(0);
177 I2C_DELAY;
wdenkc6097192002-11-03 00:24:07 +0000178 I2C_ACTIVE;
Wolfgang Denkc15f80e2006-03-13 00:50:48 +0100179 I2C_SDA(ack);
wdenkc6097192002-11-03 00:24:07 +0000180 I2C_DELAY;
181 I2C_SCL(1);
182 I2C_DELAY;
183 I2C_DELAY;
184 I2C_SCL(0);
185 I2C_DELAY;
186}
187
188
189/*-----------------------------------------------------------------------
190 * Send 8 bits and look for an acknowledgement.
191 */
192static int write_byte(uchar data)
193{
194#ifdef CONFIG_MPC8260
195 volatile ioport_t *iop = ioport_addr((immap_t *)CFG_IMMR, I2C_PORT);
196#endif
197#ifdef CONFIG_8xx
198 volatile immap_t *immr = (immap_t *)CFG_IMMR;
199#endif
200 int j;
201 int nack;
202
203 I2C_ACTIVE;
204 for(j = 0; j < 8; j++) {
205 I2C_SCL(0);
206 I2C_DELAY;
207 I2C_SDA(data & 0x80);
208 I2C_DELAY;
209 I2C_SCL(1);
210 I2C_DELAY;
211 I2C_DELAY;
212
213 data <<= 1;
214 }
215
216 /*
217 * Look for an <ACK>(negative logic) and return it.
218 */
219 I2C_SCL(0);
220 I2C_DELAY;
221 I2C_SDA(1);
222 I2C_TRISTATE;
223 I2C_DELAY;
224 I2C_SCL(1);
225 I2C_DELAY;
226 I2C_DELAY;
227 nack = I2C_READ;
228 I2C_SCL(0);
229 I2C_DELAY;
230 I2C_ACTIVE;
231
232 return(nack); /* not a nack is an ack */
233}
234
235
236/*-----------------------------------------------------------------------
237 * if ack == I2C_ACK, ACK the byte so can continue reading, else
238 * send I2C_NOACK to end the read.
239 */
240static uchar read_byte(int ack)
241{
242#ifdef CONFIG_MPC8260
243 volatile ioport_t *iop = ioport_addr((immap_t *)CFG_IMMR, I2C_PORT);
244#endif
245#ifdef CONFIG_8xx
246 volatile immap_t *immr = (immap_t *)CFG_IMMR;
247#endif
248 int data;
249 int j;
250
251 /*
252 * Read 8 bits, MSB first.
253 */
254 I2C_TRISTATE;
255 data = 0;
256 for(j = 0; j < 8; j++) {
257 I2C_SCL(0);
258 I2C_DELAY;
259 I2C_SCL(1);
260 I2C_DELAY;
261 data <<= 1;
262 data |= I2C_READ;
263 I2C_DELAY;
264 }
265 send_ack(ack);
266
267 return(data);
268}
269
270/*=====================================================================*/
271/* Public Functions */
272/*=====================================================================*/
273
274/*-----------------------------------------------------------------------
275 * Initialization
276 */
277void i2c_init (int speed, int slaveaddr)
278{
wdenkc6097192002-11-03 00:24:07 +0000279 /*
wdenk8bde7f72003-06-27 21:31:46 +0000280 * WARNING: Do NOT save speed in a static variable: if the
281 * I2C routines are called before RAM is initialized (to read
282 * the DIMM SPD, for instance), RAM won't be usable and your
283 * system will crash.
wdenkc6097192002-11-03 00:24:07 +0000284 */
285 send_reset ();
286}
287
288/*-----------------------------------------------------------------------
289 * Probe to see if a chip is present. Also good for checking for the
290 * completion of EEPROM writes since the chip stops responding until
291 * the write completes (typically 10mSec).
292 */
293int i2c_probe(uchar addr)
294{
295 int rc;
296
Wolfgang Denk82d716f2006-03-12 01:30:45 +0100297 /*
Wolfgang Denk8e7b7032006-03-12 02:55:22 +0100298 * perform 1 byte write transaction with just address byte
Wolfgang Denk82d716f2006-03-12 01:30:45 +0100299 * (fake write)
300 */
wdenkc6097192002-11-03 00:24:07 +0000301 send_start();
wdenk6aff3112002-12-17 01:51:00 +0000302 rc = write_byte ((addr << 1) | 0);
wdenkc6097192002-11-03 00:24:07 +0000303 send_stop();
304
305 return (rc ? 1 : 0);
306}
307
308/*-----------------------------------------------------------------------
309 * Read bytes
310 */
311int i2c_read(uchar chip, uint addr, int alen, uchar *buffer, int len)
312{
313 int shift;
314 PRINTD("i2c_read: chip %02X addr %02X alen %d buffer %p len %d\n",
315 chip, addr, alen, buffer, len);
316
317#ifdef CFG_I2C_EEPROM_ADDR_OVERFLOW
318 /*
319 * EEPROM chips that implement "address overflow" are ones
320 * like Catalyst 24WC04/08/16 which has 9/10/11 bits of
321 * address and the extra bits end up in the "chip address"
322 * bit slots. This makes a 24WC08 (1Kbyte) chip look like
323 * four 256 byte chips.
324 *
325 * Note that we consider the length of the address field to
326 * still be one byte because the extra address bits are
327 * hidden in the chip address.
328 */
329 chip |= ((addr >> (alen * 8)) & CFG_I2C_EEPROM_ADDR_OVERFLOW);
330
331 PRINTD("i2c_read: fix addr_overflow: chip %02X addr %02X\n",
332 chip, addr);
333#endif
334
335 /*
336 * Do the addressing portion of a write cycle to set the
337 * chip's address pointer. If the address length is zero,
338 * don't do the normal write cycle to set the address pointer,
339 * there is no address pointer in this chip.
340 */
341 send_start();
342 if(alen > 0) {
343 if(write_byte(chip << 1)) { /* write cycle */
344 send_stop();
345 PRINTD("i2c_read, no chip responded %02X\n", chip);
346 return(1);
347 }
348 shift = (alen-1) * 8;
349 while(alen-- > 0) {
350 if(write_byte(addr >> shift)) {
351 PRINTD("i2c_read, address not <ACK>ed\n");
352 return(1);
353 }
354 shift -= 8;
355 }
356 send_stop(); /* reportedly some chips need a full stop */
357 send_start();
358 }
359 /*
360 * Send the chip address again, this time for a read cycle.
361 * Then read the data. On the last byte, we do a NACK instead
362 * of an ACK(len == 0) to terminate the read.
363 */
364 write_byte((chip << 1) | 1); /* read cycle */
365 while(len-- > 0) {
366 *buffer++ = read_byte(len == 0);
367 }
368 send_stop();
369 return(0);
370}
371
372/*-----------------------------------------------------------------------
373 * Write bytes
374 */
375int i2c_write(uchar chip, uint addr, int alen, uchar *buffer, int len)
376{
377 int shift, failures = 0;
378
379 PRINTD("i2c_write: chip %02X addr %02X alen %d buffer %p len %d\n",
380 chip, addr, alen, buffer, len);
381
382 send_start();
383 if(write_byte(chip << 1)) { /* write cycle */
384 send_stop();
385 PRINTD("i2c_write, no chip responded %02X\n", chip);
386 return(1);
387 }
388 shift = (alen-1) * 8;
389 while(alen-- > 0) {
390 if(write_byte(addr >> shift)) {
391 PRINTD("i2c_write, address not <ACK>ed\n");
392 return(1);
393 }
394 shift -= 8;
395 }
396
397 while(len-- > 0) {
398 if(write_byte(*buffer++)) {
399 failures++;
400 }
401 }
402 send_stop();
403 return(failures);
404}
405
406/*-----------------------------------------------------------------------
407 * Read a register
408 */
409uchar i2c_reg_read(uchar i2c_addr, uchar reg)
410{
Wolfgang Denk77ddac92005-10-13 16:45:02 +0200411 uchar buf;
wdenkc6097192002-11-03 00:24:07 +0000412
413 i2c_read(i2c_addr, reg, 1, &buf, 1);
414
415 return(buf);
416}
417
418/*-----------------------------------------------------------------------
419 * Write a register
420 */
421void i2c_reg_write(uchar i2c_addr, uchar reg, uchar val)
422{
423 i2c_write(i2c_addr, reg, 1, &val, 1);
424}
425
426
427#endif /* CONFIG_SOFT_I2C */