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Merge branch 'master' of git://git.denx.de/u-boot-tegra
[u-boot] / drivers / i2c / soft_i2c.c
1 /*
2  * (C) Copyright 2009
3  * Heiko Schocher, DENX Software Engineering, hs@denx.de.
4  * Changes for multibus/multiadapter I2C support.
5  *
6  * (C) Copyright 2001, 2002
7  * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
8  *
9  * SPDX-License-Identifier:     GPL-2.0+
10  *
11  * This has been changed substantially by Gerald Van Baren, Custom IDEAS,
12  * vanbaren@cideas.com.  It was heavily influenced by LiMon, written by
13  * Neil Russell.
14  *
15  * NOTE: This driver should be converted to driver model before June 2017.
16  * Please see doc/driver-model/i2c-howto.txt for instructions.
17  */
18
19 #include <common.h>
20 #if defined(CONFIG_AVR32)
21 #include <asm/arch/portmux.h>
22 #endif
23 #if defined(CONFIG_AT91FAMILY)
24 #include <asm/io.h>
25 #include <asm/arch/hardware.h>
26 #include <asm/arch/at91_pio.h>
27 #ifdef CONFIG_ATMEL_LEGACY
28 #include <asm/arch/gpio.h>
29 #endif
30 #endif
31 #if defined(CONFIG_MPC852T) || defined(CONFIG_MPC866)
32 #include <asm/io.h>
33 #endif
34 #include <i2c.h>
35
36 #if defined(CONFIG_SOFT_I2C_GPIO_SCL)
37 # include <asm/gpio.h>
38
39 # ifndef I2C_GPIO_SYNC
40 #  define I2C_GPIO_SYNC
41 # endif
42
43 # ifndef I2C_INIT
44 #  define I2C_INIT \
45         do { \
46                 gpio_request(CONFIG_SOFT_I2C_GPIO_SCL, "soft_i2c"); \
47                 gpio_request(CONFIG_SOFT_I2C_GPIO_SDA, "soft_i2c"); \
48         } while (0)
49 # endif
50
51 # ifndef I2C_ACTIVE
52 #  define I2C_ACTIVE do { } while (0)
53 # endif
54
55 # ifndef I2C_TRISTATE
56 #  define I2C_TRISTATE do { } while (0)
57 # endif
58
59 # ifndef I2C_READ
60 #  define I2C_READ gpio_get_value(CONFIG_SOFT_I2C_GPIO_SDA)
61 # endif
62
63 # ifndef I2C_SDA
64 #  define I2C_SDA(bit) \
65         do { \
66                 if (bit) \
67                         gpio_direction_input(CONFIG_SOFT_I2C_GPIO_SDA); \
68                 else \
69                         gpio_direction_output(CONFIG_SOFT_I2C_GPIO_SDA, 0); \
70                 I2C_GPIO_SYNC; \
71         } while (0)
72 # endif
73
74 # ifndef I2C_SCL
75 #  define I2C_SCL(bit) \
76         do { \
77                 gpio_direction_output(CONFIG_SOFT_I2C_GPIO_SCL, bit); \
78                 I2C_GPIO_SYNC; \
79         } while (0)
80 # endif
81
82 # ifndef I2C_DELAY
83 #  define I2C_DELAY udelay(5)   /* 1/4 I2C clock duration */
84 # endif
85
86 #endif
87
88 /* #define      DEBUG_I2C       */
89
90 DECLARE_GLOBAL_DATA_PTR;
91
92 #ifndef I2C_SOFT_DECLARATIONS
93 #  define I2C_SOFT_DECLARATIONS
94 #endif
95
96 #if !defined(CONFIG_SYS_I2C_SOFT_SPEED)
97 #define CONFIG_SYS_I2C_SOFT_SPEED CONFIG_SYS_I2C_SPEED
98 #endif
99 #if !defined(CONFIG_SYS_I2C_SOFT_SLAVE)
100 #define CONFIG_SYS_I2C_SOFT_SLAVE CONFIG_SYS_I2C_SLAVE
101 #endif
102
103 /*-----------------------------------------------------------------------
104  * Definitions
105  */
106 #define RETRIES         0
107
108 #define I2C_ACK         0               /* PD_SDA level to ack a byte */
109 #define I2C_NOACK       1               /* PD_SDA level to noack a byte */
110
111
112 #ifdef DEBUG_I2C
113 #define PRINTD(fmt,args...)     do {    \
114                 printf (fmt ,##args);   \
115         } while (0)
116 #else
117 #define PRINTD(fmt,args...)
118 #endif
119
120 /*-----------------------------------------------------------------------
121  * Local functions
122  */
123 #if !defined(CONFIG_SYS_I2C_INIT_BOARD)
124 static void  send_reset (void);
125 #endif
126 static void  send_start (void);
127 static void  send_stop  (void);
128 static void  send_ack   (int);
129 static int   write_byte (uchar byte);
130 static uchar read_byte  (int);
131
132 #if !defined(CONFIG_SYS_I2C_INIT_BOARD)
133 /*-----------------------------------------------------------------------
134  * Send a reset sequence consisting of 9 clocks with the data signal high
135  * to clock any confused device back into an idle state.  Also send a
136  * <stop> at the end of the sequence for belts & suspenders.
137  */
138 static void send_reset(void)
139 {
140         I2C_SOFT_DECLARATIONS   /* intentional without ';' */
141         int j;
142
143         I2C_SCL(1);
144         I2C_SDA(1);
145 #ifdef  I2C_INIT
146         I2C_INIT;
147 #endif
148         I2C_TRISTATE;
149         for(j = 0; j < 9; j++) {
150                 I2C_SCL(0);
151                 I2C_DELAY;
152                 I2C_DELAY;
153                 I2C_SCL(1);
154                 I2C_DELAY;
155                 I2C_DELAY;
156         }
157         send_stop();
158         I2C_TRISTATE;
159 }
160 #endif
161
162 /*-----------------------------------------------------------------------
163  * START: High -> Low on SDA while SCL is High
164  */
165 static void send_start(void)
166 {
167         I2C_SOFT_DECLARATIONS   /* intentional without ';' */
168
169         I2C_DELAY;
170         I2C_SDA(1);
171         I2C_ACTIVE;
172         I2C_DELAY;
173         I2C_SCL(1);
174         I2C_DELAY;
175         I2C_SDA(0);
176         I2C_DELAY;
177 }
178
179 /*-----------------------------------------------------------------------
180  * STOP: Low -> High on SDA while SCL is High
181  */
182 static void send_stop(void)
183 {
184         I2C_SOFT_DECLARATIONS   /* intentional without ';' */
185
186         I2C_SCL(0);
187         I2C_DELAY;
188         I2C_SDA(0);
189         I2C_ACTIVE;
190         I2C_DELAY;
191         I2C_SCL(1);
192         I2C_DELAY;
193         I2C_SDA(1);
194         I2C_DELAY;
195         I2C_TRISTATE;
196 }
197
198 /*-----------------------------------------------------------------------
199  * ack should be I2C_ACK or I2C_NOACK
200  */
201 static void send_ack(int ack)
202 {
203         I2C_SOFT_DECLARATIONS   /* intentional without ';' */
204
205         I2C_SCL(0);
206         I2C_DELAY;
207         I2C_ACTIVE;
208         I2C_SDA(ack);
209         I2C_DELAY;
210         I2C_SCL(1);
211         I2C_DELAY;
212         I2C_DELAY;
213         I2C_SCL(0);
214         I2C_DELAY;
215 }
216
217 /*-----------------------------------------------------------------------
218  * Send 8 bits and look for an acknowledgement.
219  */
220 static int write_byte(uchar data)
221 {
222         I2C_SOFT_DECLARATIONS   /* intentional without ';' */
223         int j;
224         int nack;
225
226         I2C_ACTIVE;
227         for(j = 0; j < 8; j++) {
228                 I2C_SCL(0);
229                 I2C_DELAY;
230                 I2C_SDA(data & 0x80);
231                 I2C_DELAY;
232                 I2C_SCL(1);
233                 I2C_DELAY;
234                 I2C_DELAY;
235
236                 data <<= 1;
237         }
238
239         /*
240          * Look for an <ACK>(negative logic) and return it.
241          */
242         I2C_SCL(0);
243         I2C_DELAY;
244         I2C_SDA(1);
245         I2C_TRISTATE;
246         I2C_DELAY;
247         I2C_SCL(1);
248         I2C_DELAY;
249         I2C_DELAY;
250         nack = I2C_READ;
251         I2C_SCL(0);
252         I2C_DELAY;
253         I2C_ACTIVE;
254
255         return(nack);   /* not a nack is an ack */
256 }
257
258 /*-----------------------------------------------------------------------
259  * if ack == I2C_ACK, ACK the byte so can continue reading, else
260  * send I2C_NOACK to end the read.
261  */
262 static uchar read_byte(int ack)
263 {
264         I2C_SOFT_DECLARATIONS   /* intentional without ';' */
265         int  data;
266         int  j;
267
268         /*
269          * Read 8 bits, MSB first.
270          */
271         I2C_TRISTATE;
272         I2C_SDA(1);
273         data = 0;
274         for(j = 0; j < 8; j++) {
275                 I2C_SCL(0);
276                 I2C_DELAY;
277                 I2C_SCL(1);
278                 I2C_DELAY;
279                 data <<= 1;
280                 data |= I2C_READ;
281                 I2C_DELAY;
282         }
283         send_ack(ack);
284
285         return(data);
286 }
287
288 /*-----------------------------------------------------------------------
289  * Initialization
290  */
291 static void soft_i2c_init(struct i2c_adapter *adap, int speed, int slaveaddr)
292 {
293 #if defined(CONFIG_SYS_I2C_INIT_BOARD)
294         /* call board specific i2c bus reset routine before accessing the   */
295         /* environment, which might be in a chip on that bus. For details   */
296         /* about this problem see doc/I2C_Edge_Conditions.                  */
297         i2c_init_board();
298 #else
299         /*
300          * WARNING: Do NOT save speed in a static variable: if the
301          * I2C routines are called before RAM is initialized (to read
302          * the DIMM SPD, for instance), RAM won't be usable and your
303          * system will crash.
304          */
305         send_reset ();
306 #endif
307 }
308
309 /*-----------------------------------------------------------------------
310  * Probe to see if a chip is present.  Also good for checking for the
311  * completion of EEPROM writes since the chip stops responding until
312  * the write completes (typically 10mSec).
313  */
314 static int soft_i2c_probe(struct i2c_adapter *adap, uint8_t addr)
315 {
316         int rc;
317
318         /*
319          * perform 1 byte write transaction with just address byte
320          * (fake write)
321          */
322         send_start();
323         rc = write_byte ((addr << 1) | 0);
324         send_stop();
325
326         return (rc ? 1 : 0);
327 }
328
329 /*-----------------------------------------------------------------------
330  * Read bytes
331  */
332 static int  soft_i2c_read(struct i2c_adapter *adap, uchar chip, uint addr,
333                         int alen, uchar *buffer, int len)
334 {
335         int shift;
336         PRINTD("i2c_read: chip %02X addr %02X alen %d buffer %p len %d\n",
337                 chip, addr, alen, buffer, len);
338
339 #ifdef CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW
340         /*
341          * EEPROM chips that implement "address overflow" are ones
342          * like Catalyst 24WC04/08/16 which has 9/10/11 bits of
343          * address and the extra bits end up in the "chip address"
344          * bit slots. This makes a 24WC08 (1Kbyte) chip look like
345          * four 256 byte chips.
346          *
347          * Note that we consider the length of the address field to
348          * still be one byte because the extra address bits are
349          * hidden in the chip address.
350          */
351         chip |= ((addr >> (alen * 8)) & CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW);
352
353         PRINTD("i2c_read: fix addr_overflow: chip %02X addr %02X\n",
354                 chip, addr);
355 #endif
356
357         /*
358          * Do the addressing portion of a write cycle to set the
359          * chip's address pointer.  If the address length is zero,
360          * don't do the normal write cycle to set the address pointer,
361          * there is no address pointer in this chip.
362          */
363         send_start();
364         if(alen > 0) {
365                 if(write_byte(chip << 1)) {     /* write cycle */
366                         send_stop();
367                         PRINTD("i2c_read, no chip responded %02X\n", chip);
368                         return(1);
369                 }
370                 shift = (alen-1) * 8;
371                 while(alen-- > 0) {
372                         if(write_byte(addr >> shift)) {
373                                 PRINTD("i2c_read, address not <ACK>ed\n");
374                                 return(1);
375                         }
376                         shift -= 8;
377                 }
378
379                 /* Some I2C chips need a stop/start sequence here,
380                  * other chips don't work with a full stop and need
381                  * only a start.  Default behaviour is to send the
382                  * stop/start sequence.
383                  */
384 #ifdef CONFIG_SOFT_I2C_READ_REPEATED_START
385                 send_start();
386 #else
387                 send_stop();
388                 send_start();
389 #endif
390         }
391         /*
392          * Send the chip address again, this time for a read cycle.
393          * Then read the data.  On the last byte, we do a NACK instead
394          * of an ACK(len == 0) to terminate the read.
395          */
396         write_byte((chip << 1) | 1);    /* read cycle */
397         while(len-- > 0) {
398                 *buffer++ = read_byte(len == 0);
399         }
400         send_stop();
401         return(0);
402 }
403
404 /*-----------------------------------------------------------------------
405  * Write bytes
406  */
407 static int  soft_i2c_write(struct i2c_adapter *adap, uchar chip, uint addr,
408                         int alen, uchar *buffer, int len)
409 {
410         int shift, failures = 0;
411
412         PRINTD("i2c_write: chip %02X addr %02X alen %d buffer %p len %d\n",
413                 chip, addr, alen, buffer, len);
414
415         send_start();
416         if(write_byte(chip << 1)) {     /* write cycle */
417                 send_stop();
418                 PRINTD("i2c_write, no chip responded %02X\n", chip);
419                 return(1);
420         }
421         shift = (alen-1) * 8;
422         while(alen-- > 0) {
423                 if(write_byte(addr >> shift)) {
424                         PRINTD("i2c_write, address not <ACK>ed\n");
425                         return(1);
426                 }
427                 shift -= 8;
428         }
429
430         while(len-- > 0) {
431                 if(write_byte(*buffer++)) {
432                         failures++;
433                 }
434         }
435         send_stop();
436         return(failures);
437 }
438
439 /*
440  * Register soft i2c adapters
441  */
442 U_BOOT_I2C_ADAP_COMPLETE(soft00, soft_i2c_init, soft_i2c_probe,
443                          soft_i2c_read, soft_i2c_write, NULL,
444                          CONFIG_SYS_I2C_SOFT_SPEED, CONFIG_SYS_I2C_SOFT_SLAVE,
445                          0)
446 #if defined(I2C_SOFT_DECLARATIONS2)
447 U_BOOT_I2C_ADAP_COMPLETE(soft01, soft_i2c_init, soft_i2c_probe,
448                          soft_i2c_read, soft_i2c_write, NULL,
449                          CONFIG_SYS_I2C_SOFT_SPEED_2,
450                          CONFIG_SYS_I2C_SOFT_SLAVE_2,
451                          1)
452 #endif
453 #if defined(I2C_SOFT_DECLARATIONS3)
454 U_BOOT_I2C_ADAP_COMPLETE(soft02, soft_i2c_init, soft_i2c_probe,
455                          soft_i2c_read, soft_i2c_write, NULL,
456                          CONFIG_SYS_I2C_SOFT_SPEED_3,
457                          CONFIG_SYS_I2C_SOFT_SLAVE_3,
458                          2)
459 #endif
460 #if defined(I2C_SOFT_DECLARATIONS4)
461 U_BOOT_I2C_ADAP_COMPLETE(soft03, soft_i2c_init, soft_i2c_probe,
462                          soft_i2c_read, soft_i2c_write, NULL,
463                          CONFIG_SYS_I2C_SOFT_SPEED_4,
464                          CONFIG_SYS_I2C_SOFT_SLAVE_4,
465                          3)
466 #endif
467 #if defined(I2C_SOFT_DECLARATIONS5)
468 U_BOOT_I2C_ADAP_COMPLETE(soft04, soft_i2c_init, soft_i2c_probe,
469                          soft_i2c_read, soft_i2c_write, NULL,
470                          CONFIG_SYS_I2C_SOFT_SPEED_5,
471                          CONFIG_SYS_I2C_SOFT_SLAVE_5,
472                          4)
473 #endif
474 #if defined(I2C_SOFT_DECLARATIONS6)
475 U_BOOT_I2C_ADAP_COMPLETE(soft05, soft_i2c_init, soft_i2c_probe,
476                          soft_i2c_read, soft_i2c_write, NULL,
477                          CONFIG_SYS_I2C_SOFT_SPEED_6,
478                          CONFIG_SYS_I2C_SOFT_SLAVE_6,
479                          5)
480 #endif
481 #if defined(I2C_SOFT_DECLARATIONS7)
482 U_BOOT_I2C_ADAP_COMPLETE(soft06, soft_i2c_init, soft_i2c_probe,
483                          soft_i2c_read, soft_i2c_write, NULL,
484                          CONFIG_SYS_I2C_SOFT_SPEED_7,
485                          CONFIG_SYS_I2C_SOFT_SLAVE_7,
486                          6)
487 #endif
488 #if defined(I2C_SOFT_DECLARATIONS8)
489 U_BOOT_I2C_ADAP_COMPLETE(soft07, soft_i2c_init, soft_i2c_probe,
490                          soft_i2c_read, soft_i2c_write, NULL,
491                          CONFIG_SYS_I2C_SOFT_SPEED_8,
492                          CONFIG_SYS_I2C_SOFT_SLAVE_8,
493                          7)
494 #endif
495 #if defined(I2C_SOFT_DECLARATIONS9)
496 U_BOOT_I2C_ADAP_COMPLETE(soft08, soft_i2c_init, soft_i2c_probe,
497                          soft_i2c_read, soft_i2c_write, NULL,
498                          CONFIG_SYS_I2C_SOFT_SPEED_9,
499                          CONFIG_SYS_I2C_SOFT_SLAVE_9,
500                          8)
501 #endif
502 #if defined(I2C_SOFT_DECLARATIONS10)
503 U_BOOT_I2C_ADAP_COMPLETE(soft09, soft_i2c_init, soft_i2c_probe,
504                          soft_i2c_read, soft_i2c_write, NULL,
505                          CONFIG_SYS_I2C_SOFT_SPEED_10,
506                          CONFIG_SYS_I2C_SOFT_SLAVE_10,
507                          9)
508 #endif
509 #if defined(I2C_SOFT_DECLARATIONS11)
510 U_BOOT_I2C_ADAP_COMPLETE(soft10, soft_i2c_init, soft_i2c_probe,
511                          soft_i2c_read, soft_i2c_write, NULL,
512                          CONFIG_SYS_I2C_SOFT_SPEED_11,
513                          CONFIG_SYS_I2C_SOFT_SLAVE_11,
514                          10)
515 #endif
516 #if defined(I2C_SOFT_DECLARATIONS12)
517 U_BOOT_I2C_ADAP_COMPLETE(soft11, soft_i2c_init, soft_i2c_probe,
518                          soft_i2c_read, soft_i2c_write, NULL,
519                          CONFIG_SYS_I2C_SOFT_SPEED_12,
520                          CONFIG_SYS_I2C_SOFT_SLAVE_12,
521                          11)
522 #endif