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1 /*
2  * (C) Copyright 2001, 2002
3  * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
4  *
5  * SPDX-License-Identifier:     GPL-2.0+
6  *
7  * This has been changed substantially by Gerald Van Baren, Custom IDEAS,
8  * vanbaren@cideas.com.  It was heavily influenced by LiMon, written by
9  * Neil Russell.
10  */
11
12 #include <common.h>
13 #ifdef  CONFIG_MPC8260                  /* only valid for MPC8260 */
14 #include <ioports.h>
15 #include <asm/io.h>
16 #endif
17 #if defined(CONFIG_AVR32)
18 #include <asm/arch/portmux.h>
19 #endif
20 #if defined(CONFIG_AT91FAMILY)
21 #include <asm/io.h>
22 #include <asm/arch/hardware.h>
23 #include <asm/arch/at91_pio.h>
24 #ifdef CONFIG_AT91_LEGACY
25 #include <asm/arch/gpio.h>
26 #endif
27 #endif
28 #ifdef  CONFIG_IXP425                   /* only valid for IXP425 */
29 #include <asm/arch/ixp425.h>
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 #ifdef DEBUG_I2C
91 DECLARE_GLOBAL_DATA_PTR;
92 #endif
93
94 /*-----------------------------------------------------------------------
95  * Definitions
96  */
97
98 #define RETRIES         0
99
100 #define I2C_ACK         0               /* PD_SDA level to ack a byte */
101 #define I2C_NOACK       1               /* PD_SDA level to noack a byte */
102
103
104 #ifdef DEBUG_I2C
105 #define PRINTD(fmt,args...)     do {    \
106                 printf (fmt ,##args);   \
107         } while (0)
108 #else
109 #define PRINTD(fmt,args...)
110 #endif
111
112 #if defined(CONFIG_I2C_MULTI_BUS)
113 static unsigned int i2c_bus_num __attribute__ ((section (".data"))) = 0;
114 #endif /* CONFIG_I2C_MULTI_BUS */
115
116 /*-----------------------------------------------------------------------
117  * Local functions
118  */
119 #if !defined(CONFIG_SYS_I2C_INIT_BOARD)
120 static void  send_reset (void);
121 #endif
122 static void  send_start (void);
123 static void  send_stop  (void);
124 static void  send_ack   (int);
125 static int   write_byte (uchar byte);
126 static uchar read_byte  (int);
127
128 #if !defined(CONFIG_SYS_I2C_INIT_BOARD)
129 /*-----------------------------------------------------------------------
130  * Send a reset sequence consisting of 9 clocks with the data signal high
131  * to clock any confused device back into an idle state.  Also send a
132  * <stop> at the end of the sequence for belts & suspenders.
133  */
134 static void send_reset(void)
135 {
136         I2C_SOFT_DECLARATIONS   /* intentional without ';' */
137         int j;
138
139         I2C_SCL(1);
140         I2C_SDA(1);
141 #ifdef  I2C_INIT
142         I2C_INIT;
143 #endif
144         I2C_TRISTATE;
145         for(j = 0; j < 9; j++) {
146                 I2C_SCL(0);
147                 I2C_DELAY;
148                 I2C_DELAY;
149                 I2C_SCL(1);
150                 I2C_DELAY;
151                 I2C_DELAY;
152         }
153         send_stop();
154         I2C_TRISTATE;
155 }
156 #endif
157
158 /*-----------------------------------------------------------------------
159  * START: High -> Low on SDA while SCL is High
160  */
161 static void send_start(void)
162 {
163         I2C_SOFT_DECLARATIONS   /* intentional without ';' */
164
165         I2C_DELAY;
166         I2C_SDA(1);
167         I2C_ACTIVE;
168         I2C_DELAY;
169         I2C_SCL(1);
170         I2C_DELAY;
171         I2C_SDA(0);
172         I2C_DELAY;
173 }
174
175 /*-----------------------------------------------------------------------
176  * STOP: Low -> High on SDA while SCL is High
177  */
178 static void send_stop(void)
179 {
180         I2C_SOFT_DECLARATIONS   /* intentional without ';' */
181
182         I2C_SCL(0);
183         I2C_DELAY;
184         I2C_SDA(0);
185         I2C_ACTIVE;
186         I2C_DELAY;
187         I2C_SCL(1);
188         I2C_DELAY;
189         I2C_SDA(1);
190         I2C_DELAY;
191         I2C_TRISTATE;
192 }
193
194 /*-----------------------------------------------------------------------
195  * ack should be I2C_ACK or I2C_NOACK
196  */
197 static void send_ack(int ack)
198 {
199         I2C_SOFT_DECLARATIONS   /* intentional without ';' */
200
201         I2C_SCL(0);
202         I2C_DELAY;
203         I2C_ACTIVE;
204         I2C_SDA(ack);
205         I2C_DELAY;
206         I2C_SCL(1);
207         I2C_DELAY;
208         I2C_DELAY;
209         I2C_SCL(0);
210         I2C_DELAY;
211 }
212
213 /*-----------------------------------------------------------------------
214  * Send 8 bits and look for an acknowledgement.
215  */
216 static int write_byte(uchar data)
217 {
218         I2C_SOFT_DECLARATIONS   /* intentional without ';' */
219         int j;
220         int nack;
221
222         I2C_ACTIVE;
223         for(j = 0; j < 8; j++) {
224                 I2C_SCL(0);
225                 I2C_DELAY;
226                 I2C_SDA(data & 0x80);
227                 I2C_DELAY;
228                 I2C_SCL(1);
229                 I2C_DELAY;
230                 I2C_DELAY;
231
232                 data <<= 1;
233         }
234
235         /*
236          * Look for an <ACK>(negative logic) and return it.
237          */
238         I2C_SCL(0);
239         I2C_DELAY;
240         I2C_SDA(1);
241         I2C_TRISTATE;
242         I2C_DELAY;
243         I2C_SCL(1);
244         I2C_DELAY;
245         I2C_DELAY;
246         nack = I2C_READ;
247         I2C_SCL(0);
248         I2C_DELAY;
249         I2C_ACTIVE;
250
251         return(nack);   /* not a nack is an ack */
252 }
253
254 #if defined(CONFIG_I2C_MULTI_BUS)
255 /*
256  * Functions for multiple I2C bus handling
257  */
258 unsigned int i2c_get_bus_num(void)
259 {
260         return i2c_bus_num;
261 }
262
263 int i2c_set_bus_num(unsigned int bus)
264 {
265 #if defined(CONFIG_I2C_MUX)
266         if (bus < CONFIG_SYS_MAX_I2C_BUS) {
267                 i2c_bus_num = bus;
268         } else {
269                 int     ret;
270
271                 ret = i2x_mux_select_mux(bus);
272                 i2c_init_board();
273                 if (ret == 0)
274                         i2c_bus_num = bus;
275                 else
276                         return ret;
277         }
278 #else
279         if (bus >= CONFIG_SYS_MAX_I2C_BUS)
280                 return -1;
281         i2c_bus_num = bus;
282 #endif
283         return 0;
284 }
285 #endif
286
287 /*-----------------------------------------------------------------------
288  * if ack == I2C_ACK, ACK the byte so can continue reading, else
289  * send I2C_NOACK to end the read.
290  */
291 static uchar read_byte(int ack)
292 {
293         I2C_SOFT_DECLARATIONS   /* intentional without ';' */
294         int  data;
295         int  j;
296
297         /*
298          * Read 8 bits, MSB first.
299          */
300         I2C_TRISTATE;
301         I2C_SDA(1);
302         data = 0;
303         for(j = 0; j < 8; j++) {
304                 I2C_SCL(0);
305                 I2C_DELAY;
306                 I2C_SCL(1);
307                 I2C_DELAY;
308                 data <<= 1;
309                 data |= I2C_READ;
310                 I2C_DELAY;
311         }
312         send_ack(ack);
313
314         return(data);
315 }
316
317 /*=====================================================================*/
318 /*                         Public Functions                            */
319 /*=====================================================================*/
320
321 /*-----------------------------------------------------------------------
322  * Initialization
323  */
324 void i2c_init (int speed, int slaveaddr)
325 {
326 #if defined(CONFIG_SYS_I2C_INIT_BOARD)
327         /* call board specific i2c bus reset routine before accessing the   */
328         /* environment, which might be in a chip on that bus. For details   */
329         /* about this problem see doc/I2C_Edge_Conditions.                  */
330         i2c_init_board();
331 #else
332         /*
333          * WARNING: Do NOT save speed in a static variable: if the
334          * I2C routines are called before RAM is initialized (to read
335          * the DIMM SPD, for instance), RAM won't be usable and your
336          * system will crash.
337          */
338         send_reset ();
339 #endif
340 }
341
342 /*-----------------------------------------------------------------------
343  * Probe to see if a chip is present.  Also good for checking for the
344  * completion of EEPROM writes since the chip stops responding until
345  * the write completes (typically 10mSec).
346  */
347 int i2c_probe(uchar addr)
348 {
349         int rc;
350
351         /*
352          * perform 1 byte write transaction with just address byte
353          * (fake write)
354          */
355         send_start();
356         rc = write_byte ((addr << 1) | 0);
357         send_stop();
358
359         return (rc ? 1 : 0);
360 }
361
362 /*-----------------------------------------------------------------------
363  * Read bytes
364  */
365 int  i2c_read(uchar chip, uint addr, int alen, uchar *buffer, int len)
366 {
367         int shift;
368         PRINTD("i2c_read: chip %02X addr %02X alen %d buffer %p len %d\n",
369                 chip, addr, alen, buffer, len);
370
371 #ifdef CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW
372         /*
373          * EEPROM chips that implement "address overflow" are ones
374          * like Catalyst 24WC04/08/16 which has 9/10/11 bits of
375          * address and the extra bits end up in the "chip address"
376          * bit slots. This makes a 24WC08 (1Kbyte) chip look like
377          * four 256 byte chips.
378          *
379          * Note that we consider the length of the address field to
380          * still be one byte because the extra address bits are
381          * hidden in the chip address.
382          */
383         chip |= ((addr >> (alen * 8)) & CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW);
384
385         PRINTD("i2c_read: fix addr_overflow: chip %02X addr %02X\n",
386                 chip, addr);
387 #endif
388
389         /*
390          * Do the addressing portion of a write cycle to set the
391          * chip's address pointer.  If the address length is zero,
392          * don't do the normal write cycle to set the address pointer,
393          * there is no address pointer in this chip.
394          */
395         send_start();
396         if(alen > 0) {
397                 if(write_byte(chip << 1)) {     /* write cycle */
398                         send_stop();
399                         PRINTD("i2c_read, no chip responded %02X\n", chip);
400                         return(1);
401                 }
402                 shift = (alen-1) * 8;
403                 while(alen-- > 0) {
404                         if(write_byte(addr >> shift)) {
405                                 PRINTD("i2c_read, address not <ACK>ed\n");
406                                 return(1);
407                         }
408                         shift -= 8;
409                 }
410
411                 /* Some I2C chips need a stop/start sequence here,
412                  * other chips don't work with a full stop and need
413                  * only a start.  Default behaviour is to send the
414                  * stop/start sequence.
415                  */
416 #ifdef CONFIG_SOFT_I2C_READ_REPEATED_START
417                 send_start();
418 #else
419                 send_stop();
420                 send_start();
421 #endif
422         }
423         /*
424          * Send the chip address again, this time for a read cycle.
425          * Then read the data.  On the last byte, we do a NACK instead
426          * of an ACK(len == 0) to terminate the read.
427          */
428         write_byte((chip << 1) | 1);    /* read cycle */
429         while(len-- > 0) {
430                 *buffer++ = read_byte(len == 0);
431         }
432         send_stop();
433         return(0);
434 }
435
436 /*-----------------------------------------------------------------------
437  * Write bytes
438  */
439 int  i2c_write(uchar chip, uint addr, int alen, uchar *buffer, int len)
440 {
441         int shift, failures = 0;
442
443         PRINTD("i2c_write: chip %02X addr %02X alen %d buffer %p len %d\n",
444                 chip, addr, alen, buffer, len);
445
446         send_start();
447         if(write_byte(chip << 1)) {     /* write cycle */
448                 send_stop();
449                 PRINTD("i2c_write, no chip responded %02X\n", chip);
450                 return(1);
451         }
452         shift = (alen-1) * 8;
453         while(alen-- > 0) {
454                 if(write_byte(addr >> shift)) {
455                         PRINTD("i2c_write, address not <ACK>ed\n");
456                         return(1);
457                 }
458                 shift -= 8;
459         }
460
461         while(len-- > 0) {
462                 if(write_byte(*buffer++)) {
463                         failures++;
464                 }
465         }
466         send_stop();
467         return(failures);
468 }