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1 /*
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 #include <asm/io.h>
32 #endif
33 #if defined(CONFIG_AT91FAMILY)
34 #include <asm/io.h>
35 #include <asm/arch/hardware.h>
36 #include <asm/arch/at91_pio.h>
37 #ifdef CONFIG_AT91_LEGACY
38 #include <asm/arch/gpio.h>
39 #endif
40 #endif
41 #ifdef  CONFIG_IXP425                   /* only valid for IXP425 */
42 #include <asm/arch/ixp425.h>
43 #endif
44 #ifdef CONFIG_LPC2292
45 #include <asm/arch/hardware.h>
46 #endif
47 #if defined(CONFIG_MPC852T) || defined(CONFIG_MPC866)
48 #include <asm/io.h>
49 #endif
50 #include <i2c.h>
51
52 #if defined(CONFIG_SOFT_I2C_GPIO_SCL)
53 # include <asm/gpio.h>
54
55 # ifndef I2C_GPIO_SYNC
56 #  define I2C_GPIO_SYNC
57 # endif
58
59 # ifndef I2C_INIT
60 #  define I2C_INIT \
61         do { \
62                 gpio_request(CONFIG_SOFT_I2C_GPIO_SCL, "soft_i2c"); \
63                 gpio_request(CONFIG_SOFT_I2C_GPIO_SDA, "soft_i2c"); \
64         } while (0)
65 # endif
66
67 # ifndef I2C_ACTIVE
68 #  define I2C_ACTIVE do { } while (0)
69 # endif
70
71 # ifndef I2C_TRISTATE
72 #  define I2C_TRISTATE do { } while (0)
73 # endif
74
75 # ifndef I2C_READ
76 #  define I2C_READ gpio_get_value(CONFIG_SOFT_I2C_GPIO_SDA)
77 # endif
78
79 # ifndef I2C_SDA
80 #  define I2C_SDA(bit) \
81         do { \
82                 if (bit) \
83                         gpio_direction_input(CONFIG_SOFT_I2C_GPIO_SDA); \
84                 else \
85                         gpio_direction_output(CONFIG_SOFT_I2C_GPIO_SDA, 0); \
86                 I2C_GPIO_SYNC; \
87         } while (0)
88 # endif
89
90 # ifndef I2C_SCL
91 #  define I2C_SCL(bit) \
92         do { \
93                 gpio_direction_output(CONFIG_SOFT_I2C_GPIO_SCL, bit); \
94                 I2C_GPIO_SYNC; \
95         } while (0)
96 # endif
97
98 # ifndef I2C_DELAY
99 #  define I2C_DELAY udelay(5)   /* 1/4 I2C clock duration */
100 # endif
101
102 #endif
103
104 /* #define      DEBUG_I2C       */
105
106 #ifdef DEBUG_I2C
107 DECLARE_GLOBAL_DATA_PTR;
108 #endif
109
110 /*-----------------------------------------------------------------------
111  * Definitions
112  */
113
114 #define RETRIES         0
115
116 #define I2C_ACK         0               /* PD_SDA level to ack a byte */
117 #define I2C_NOACK       1               /* PD_SDA level to noack a byte */
118
119
120 #ifdef DEBUG_I2C
121 #define PRINTD(fmt,args...)     do {    \
122         if (gd->have_console)           \
123                 printf (fmt ,##args);   \
124         } while (0)
125 #else
126 #define PRINTD(fmt,args...)
127 #endif
128
129 #if defined(CONFIG_I2C_MULTI_BUS)
130 static unsigned int i2c_bus_num __attribute__ ((section (".data"))) = 0;
131 #endif /* CONFIG_I2C_MULTI_BUS */
132
133 /*-----------------------------------------------------------------------
134  * Local functions
135  */
136 #if !defined(CONFIG_SYS_I2C_INIT_BOARD)
137 static void  send_reset (void);
138 #endif
139 static void  send_start (void);
140 static void  send_stop  (void);
141 static void  send_ack   (int);
142 static int   write_byte (uchar byte);
143 static uchar read_byte  (int);
144
145 #if !defined(CONFIG_SYS_I2C_INIT_BOARD)
146 /*-----------------------------------------------------------------------
147  * Send a reset sequence consisting of 9 clocks with the data signal high
148  * to clock any confused device back into an idle state.  Also send a
149  * <stop> at the end of the sequence for belts & suspenders.
150  */
151 static void send_reset(void)
152 {
153         I2C_SOFT_DECLARATIONS   /* intentional without ';' */
154         int j;
155
156         I2C_SCL(1);
157         I2C_SDA(1);
158 #ifdef  I2C_INIT
159         I2C_INIT;
160 #endif
161         I2C_TRISTATE;
162         for(j = 0; j < 9; j++) {
163                 I2C_SCL(0);
164                 I2C_DELAY;
165                 I2C_DELAY;
166                 I2C_SCL(1);
167                 I2C_DELAY;
168                 I2C_DELAY;
169         }
170         send_stop();
171         I2C_TRISTATE;
172 }
173 #endif
174
175 /*-----------------------------------------------------------------------
176  * START: High -> Low on SDA while SCL is High
177  */
178 static void send_start(void)
179 {
180         I2C_SOFT_DECLARATIONS   /* intentional without ';' */
181
182         I2C_DELAY;
183         I2C_SDA(1);
184         I2C_ACTIVE;
185         I2C_DELAY;
186         I2C_SCL(1);
187         I2C_DELAY;
188         I2C_SDA(0);
189         I2C_DELAY;
190 }
191
192 /*-----------------------------------------------------------------------
193  * STOP: Low -> High on SDA while SCL is High
194  */
195 static void send_stop(void)
196 {
197         I2C_SOFT_DECLARATIONS   /* intentional without ';' */
198
199         I2C_SCL(0);
200         I2C_DELAY;
201         I2C_SDA(0);
202         I2C_ACTIVE;
203         I2C_DELAY;
204         I2C_SCL(1);
205         I2C_DELAY;
206         I2C_SDA(1);
207         I2C_DELAY;
208         I2C_TRISTATE;
209 }
210
211 /*-----------------------------------------------------------------------
212  * ack should be I2C_ACK or I2C_NOACK
213  */
214 static void send_ack(int ack)
215 {
216         I2C_SOFT_DECLARATIONS   /* intentional without ';' */
217
218         I2C_SCL(0);
219         I2C_DELAY;
220         I2C_ACTIVE;
221         I2C_SDA(ack);
222         I2C_DELAY;
223         I2C_SCL(1);
224         I2C_DELAY;
225         I2C_DELAY;
226         I2C_SCL(0);
227         I2C_DELAY;
228 }
229
230 /*-----------------------------------------------------------------------
231  * Send 8 bits and look for an acknowledgement.
232  */
233 static int write_byte(uchar data)
234 {
235         I2C_SOFT_DECLARATIONS   /* intentional without ';' */
236         int j;
237         int nack;
238
239         I2C_ACTIVE;
240         for(j = 0; j < 8; j++) {
241                 I2C_SCL(0);
242                 I2C_DELAY;
243                 I2C_SDA(data & 0x80);
244                 I2C_DELAY;
245                 I2C_SCL(1);
246                 I2C_DELAY;
247                 I2C_DELAY;
248
249                 data <<= 1;
250         }
251
252         /*
253          * Look for an <ACK>(negative logic) and return it.
254          */
255         I2C_SCL(0);
256         I2C_DELAY;
257         I2C_SDA(1);
258         I2C_TRISTATE;
259         I2C_DELAY;
260         I2C_SCL(1);
261         I2C_DELAY;
262         I2C_DELAY;
263         nack = I2C_READ;
264         I2C_SCL(0);
265         I2C_DELAY;
266         I2C_ACTIVE;
267
268         return(nack);   /* not a nack is an ack */
269 }
270
271 #if defined(CONFIG_I2C_MULTI_BUS)
272 /*
273  * Functions for multiple I2C bus handling
274  */
275 unsigned int i2c_get_bus_num(void)
276 {
277         return i2c_bus_num;
278 }
279
280 int i2c_set_bus_num(unsigned int bus)
281 {
282 #if defined(CONFIG_I2C_MUX)
283         if (bus < CONFIG_SYS_MAX_I2C_BUS) {
284                 i2c_bus_num = bus;
285         } else {
286                 int     ret;
287
288                 ret = i2x_mux_select_mux(bus);
289                 i2c_init_board();
290                 if (ret == 0)
291                         i2c_bus_num = bus;
292                 else
293                         return ret;
294         }
295 #else
296         if (bus >= CONFIG_SYS_MAX_I2C_BUS)
297                 return -1;
298         i2c_bus_num = bus;
299 #endif
300         return 0;
301 }
302 #endif
303
304 /*-----------------------------------------------------------------------
305  * if ack == I2C_ACK, ACK the byte so can continue reading, else
306  * send I2C_NOACK to end the read.
307  */
308 static uchar read_byte(int ack)
309 {
310         I2C_SOFT_DECLARATIONS   /* intentional without ';' */
311         int  data;
312         int  j;
313
314         /*
315          * Read 8 bits, MSB first.
316          */
317         I2C_TRISTATE;
318         I2C_SDA(1);
319         data = 0;
320         for(j = 0; j < 8; j++) {
321                 I2C_SCL(0);
322                 I2C_DELAY;
323                 I2C_SCL(1);
324                 I2C_DELAY;
325                 data <<= 1;
326                 data |= I2C_READ;
327                 I2C_DELAY;
328         }
329         send_ack(ack);
330
331         return(data);
332 }
333
334 /*=====================================================================*/
335 /*                         Public Functions                            */
336 /*=====================================================================*/
337
338 /*-----------------------------------------------------------------------
339  * Initialization
340  */
341 void i2c_init (int speed, int slaveaddr)
342 {
343 #if defined(CONFIG_SYS_I2C_INIT_BOARD)
344         /* call board specific i2c bus reset routine before accessing the   */
345         /* environment, which might be in a chip on that bus. For details   */
346         /* about this problem see doc/I2C_Edge_Conditions.                  */
347         i2c_init_board();
348 #else
349         /*
350          * WARNING: Do NOT save speed in a static variable: if the
351          * I2C routines are called before RAM is initialized (to read
352          * the DIMM SPD, for instance), RAM won't be usable and your
353          * system will crash.
354          */
355         send_reset ();
356 #endif
357 }
358
359 /*-----------------------------------------------------------------------
360  * Probe to see if a chip is present.  Also good for checking for the
361  * completion of EEPROM writes since the chip stops responding until
362  * the write completes (typically 10mSec).
363  */
364 int i2c_probe(uchar addr)
365 {
366         int rc;
367
368         /*
369          * perform 1 byte write transaction with just address byte
370          * (fake write)
371          */
372         send_start();
373         rc = write_byte ((addr << 1) | 0);
374         send_stop();
375
376         return (rc ? 1 : 0);
377 }
378
379 /*-----------------------------------------------------------------------
380  * Read bytes
381  */
382 int  i2c_read(uchar chip, uint addr, int alen, uchar *buffer, int len)
383 {
384         int shift;
385         PRINTD("i2c_read: chip %02X addr %02X alen %d buffer %p len %d\n",
386                 chip, addr, alen, buffer, len);
387
388 #ifdef CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW
389         /*
390          * EEPROM chips that implement "address overflow" are ones
391          * like Catalyst 24WC04/08/16 which has 9/10/11 bits of
392          * address and the extra bits end up in the "chip address"
393          * bit slots. This makes a 24WC08 (1Kbyte) chip look like
394          * four 256 byte chips.
395          *
396          * Note that we consider the length of the address field to
397          * still be one byte because the extra address bits are
398          * hidden in the chip address.
399          */
400         chip |= ((addr >> (alen * 8)) & CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW);
401
402         PRINTD("i2c_read: fix addr_overflow: chip %02X addr %02X\n",
403                 chip, addr);
404 #endif
405
406         /*
407          * Do the addressing portion of a write cycle to set the
408          * chip's address pointer.  If the address length is zero,
409          * don't do the normal write cycle to set the address pointer,
410          * there is no address pointer in this chip.
411          */
412         send_start();
413         if(alen > 0) {
414                 if(write_byte(chip << 1)) {     /* write cycle */
415                         send_stop();
416                         PRINTD("i2c_read, no chip responded %02X\n", chip);
417                         return(1);
418                 }
419                 shift = (alen-1) * 8;
420                 while(alen-- > 0) {
421                         if(write_byte(addr >> shift)) {
422                                 PRINTD("i2c_read, address not <ACK>ed\n");
423                                 return(1);
424                         }
425                         shift -= 8;
426                 }
427
428                 /* Some I2C chips need a stop/start sequence here,
429                  * other chips don't work with a full stop and need
430                  * only a start.  Default behaviour is to send the
431                  * stop/start sequence.
432                  */
433 #ifdef CONFIG_SOFT_I2C_READ_REPEATED_START
434                 send_start();
435 #else
436                 send_stop();
437                 send_start();
438 #endif
439         }
440         /*
441          * Send the chip address again, this time for a read cycle.
442          * Then read the data.  On the last byte, we do a NACK instead
443          * of an ACK(len == 0) to terminate the read.
444          */
445         write_byte((chip << 1) | 1);    /* read cycle */
446         while(len-- > 0) {
447                 *buffer++ = read_byte(len == 0);
448         }
449         send_stop();
450         return(0);
451 }
452
453 /*-----------------------------------------------------------------------
454  * Write bytes
455  */
456 int  i2c_write(uchar chip, uint addr, int alen, uchar *buffer, int len)
457 {
458         int shift, failures = 0;
459
460         PRINTD("i2c_write: chip %02X addr %02X alen %d buffer %p len %d\n",
461                 chip, addr, alen, buffer, len);
462
463         send_start();
464         if(write_byte(chip << 1)) {     /* write cycle */
465                 send_stop();
466                 PRINTD("i2c_write, no chip responded %02X\n", chip);
467                 return(1);
468         }
469         shift = (alen-1) * 8;
470         while(alen-- > 0) {
471                 if(write_byte(addr >> shift)) {
472                         PRINTD("i2c_write, address not <ACK>ed\n");
473                         return(1);
474                 }
475                 shift -= 8;
476         }
477
478         while(len-- > 0) {
479                 if(write_byte(*buffer++)) {
480                         failures++;
481                 }
482         }
483         send_stop();
484         return(failures);
485 }