1 /* ------------------------------------------------------------------------- */
2 /* i2c-algo-pcf.c i2c driver algorithms for PCF8584 adapters */
3 /* ------------------------------------------------------------------------- */
4 /* Copyright (C) 1995-1997 Simon G. Vogl
5 1998-2000 Hans Berglund
7 This program is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 2 of the License, or
10 (at your option) any later version.
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with this program; if not, write to the Free Software
19 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */
20 /* ------------------------------------------------------------------------- */
22 /* With some changes from Kyösti Mälkki <kmalkki@cc.hut.fi> and
23 Frodo Looijaard <frodol@dds.nl> ,and also from Martin Bailey
24 <mbailey@littlefeet-inc.com> */
26 /* Partially rewriten by Oleg I. Vdovikin <vdovikin@jscc.ru> to handle multiple
27 messages, proper stop/repstart signaling during receive,
30 #include <linux/kernel.h>
31 #include <linux/module.h>
32 #include <linux/delay.h>
33 #include <linux/slab.h>
34 #include <linux/init.h>
35 #include <linux/errno.h>
36 #include <linux/i2c.h>
37 #include <linux/i2c-algo-pcf.h>
38 #include "i2c-algo-pcf.h"
41 #define DEB2(x) if (i2c_debug>=2) x
42 #define DEB3(x) if (i2c_debug>=3) x /* print several statistical values*/
43 #define DEBPROTO(x) if (i2c_debug>=9) x;
44 /* debug the protocol by showing transferred bits */
45 #define DEF_TIMEOUT 16
51 /* --- setting states on the bus with the right timing: --------------- */
53 #define set_pcf(adap, ctl, val) adap->setpcf(adap->data, ctl, val)
54 #define get_pcf(adap, ctl) adap->getpcf(adap->data, ctl)
55 #define get_own(adap) adap->getown(adap->data)
56 #define get_clock(adap) adap->getclock(adap->data)
57 #define i2c_outb(adap, val) adap->setpcf(adap->data, 0, val)
58 #define i2c_inb(adap) adap->getpcf(adap->data, 0)
60 /* --- other auxiliary functions -------------------------------------- */
62 static void i2c_start(struct i2c_algo_pcf_data
*adap
)
64 DEBPROTO(printk("S "));
65 set_pcf(adap
, 1, I2C_PCF_START
);
68 static void i2c_repstart(struct i2c_algo_pcf_data
*adap
)
70 DEBPROTO(printk(" Sr "));
71 set_pcf(adap
, 1, I2C_PCF_REPSTART
);
75 static void i2c_stop(struct i2c_algo_pcf_data
*adap
)
77 DEBPROTO(printk("P\n"));
78 set_pcf(adap
, 1, I2C_PCF_STOP
);
82 static int wait_for_bb(struct i2c_algo_pcf_data
*adap
) {
84 int timeout
= DEF_TIMEOUT
;
87 status
= get_pcf(adap
, 1);
89 while (timeout
-- && !(status
& I2C_PCF_BB
)) {
90 udelay(100); /* wait for 100 us */
91 status
= get_pcf(adap
, 1);
95 printk(KERN_ERR
"Timeout waiting for Bus Busy\n");
102 static int wait_for_pin(struct i2c_algo_pcf_data
*adap
, int *status
) {
104 int timeout
= DEF_TIMEOUT
;
106 *status
= get_pcf(adap
, 1);
108 while (timeout
-- && (*status
& I2C_PCF_PIN
)) {
110 *status
= get_pcf(adap
, 1);
120 * This should perform the 'PCF8584 initialization sequence' as described
121 * in the Philips IC12 data book (1995, Aug 29).
122 * There should be a 30 clock cycle wait after reset, I assume this
123 * has been fulfilled.
124 * There should be a delay at the end equal to the longest I2C message
125 * to synchronize the BB-bit (in multimaster systems). How long is
126 * this? I assume 1 second is always long enough.
128 * vdovikin: added detect code for PCF8584
130 static int pcf_init_8584 (struct i2c_algo_pcf_data
*adap
)
134 DEB3(printk(KERN_DEBUG
"i2c-algo-pcf.o: PCF state 0x%02x\n", get_pcf(adap
, 1)));
136 /* S1=0x80: S0 selected, serial interface off */
137 set_pcf(adap
, 1, I2C_PCF_PIN
);
138 /* check to see S1 now used as R/W ctrl -
139 PCF8584 does that when ESO is zero */
140 if (((temp
= get_pcf(adap
, 1)) & 0x7f) != (0)) {
141 DEB2(printk(KERN_ERR
"i2c-algo-pcf.o: PCF detection failed -- can't select S0 (0x%02x).\n", temp
));
142 return -ENXIO
; /* definetly not PCF8584 */
145 /* load own address in S0, effective address is (own << 1) */
146 i2c_outb(adap
, get_own(adap
));
147 /* check it's really written */
148 if ((temp
= i2c_inb(adap
)) != get_own(adap
)) {
149 DEB2(printk(KERN_ERR
"i2c-algo-pcf.o: PCF detection failed -- can't set S0 (0x%02x).\n", temp
));
153 /* S1=0xA0, next byte in S2 */
154 set_pcf(adap
, 1, I2C_PCF_PIN
| I2C_PCF_ES1
);
155 /* check to see S2 now selected */
156 if (((temp
= get_pcf(adap
, 1)) & 0x7f) != I2C_PCF_ES1
) {
157 DEB2(printk(KERN_ERR
"i2c-algo-pcf.o: PCF detection failed -- can't select S2 (0x%02x).\n", temp
));
161 /* load clock register S2 */
162 i2c_outb(adap
, get_clock(adap
));
163 /* check it's really written, the only 5 lowest bits does matter */
164 if (((temp
= i2c_inb(adap
)) & 0x1f) != get_clock(adap
)) {
165 DEB2(printk(KERN_ERR
"i2c-algo-pcf.o: PCF detection failed -- can't set S2 (0x%02x).\n", temp
));
169 /* Enable serial interface, idle, S0 selected */
170 set_pcf(adap
, 1, I2C_PCF_IDLE
);
172 /* check to see PCF is really idled and we can access status register */
173 if ((temp
= get_pcf(adap
, 1)) != (I2C_PCF_PIN
| I2C_PCF_BB
)) {
174 DEB2(printk(KERN_ERR
"i2c-algo-pcf.o: PCF detection failed -- can't select S1` (0x%02x).\n", temp
));
178 printk(KERN_DEBUG
"i2c-algo-pcf.o: deteted and initialized PCF8584.\n");
184 /* ----- Utility functions
187 static inline int try_address(struct i2c_algo_pcf_data
*adap
,
188 unsigned char addr
, int retries
)
190 int i
, status
, ret
= -1;
191 for (i
=0;i
<retries
;i
++) {
192 i2c_outb(adap
, addr
);
194 status
= get_pcf(adap
, 1);
195 if (wait_for_pin(adap
, &status
) >= 0) {
196 if ((status
& I2C_PCF_LRB
) == 0) {
198 break; /* success! */
202 udelay(adap
->udelay
);
204 DEB2(if (i
) printk(KERN_DEBUG
"i2c-algo-pcf.o: needed %d retries for %d\n",i
,
210 static int pcf_sendbytes(struct i2c_adapter
*i2c_adap
, const char *buf
,
213 struct i2c_algo_pcf_data
*adap
= i2c_adap
->algo_data
;
214 int wrcount
, status
, timeout
;
216 for (wrcount
=0; wrcount
<count
; ++wrcount
) {
217 DEB2(dev_dbg(&i2c_adap
->dev
, "i2c_write: writing %2.2X\n",
219 i2c_outb(adap
, buf
[wrcount
]);
220 timeout
= wait_for_pin(adap
, &status
);
223 dev_err(&i2c_adap
->dev
, "i2c_write: error - timeout.\n");
224 return -EREMOTEIO
; /* got a better one ?? */
227 if (status
& I2C_PCF_LRB
) {
229 dev_err(&i2c_adap
->dev
, "i2c_write: error - no ack.\n");
230 return -EREMOTEIO
; /* got a better one ?? */
245 static int pcf_readbytes(struct i2c_adapter
*i2c_adap
, char *buf
,
249 struct i2c_algo_pcf_data
*adap
= i2c_adap
->algo_data
;
251 /* increment number of bytes to read by one -- read dummy byte */
252 for (i
= 0; i
<= count
; i
++) {
254 if (wait_for_pin(adap
, &status
)) {
256 dev_err(&i2c_adap
->dev
, "pcf_readbytes timed out.\n");
261 if ((status
& I2C_PCF_LRB
) && (i
!= count
)) {
263 dev_err(&i2c_adap
->dev
, "i2c_read: i2c_inb, No ack.\n");
268 if (i
== count
- 1) {
269 set_pcf(adap
, 1, I2C_PCF_ESO
);
280 buf
[i
- 1] = i2c_inb(adap
);
282 i2c_inb(adap
); /* dummy read */
290 static inline int pcf_doAddress(struct i2c_algo_pcf_data
*adap
,
291 struct i2c_msg
*msg
, int retries
)
293 unsigned short flags
= msg
->flags
;
296 if ( (flags
& I2C_M_TEN
) ) {
297 /* a ten bit address */
298 addr
= 0xf0 | (( msg
->addr
>> 7) & 0x03);
299 DEB2(printk(KERN_DEBUG
"addr0: %d\n",addr
));
300 /* try extended address code...*/
301 ret
= try_address(adap
, addr
, retries
);
303 printk(KERN_ERR
"died at extended address code.\n");
306 /* the remaining 8 bit address */
307 i2c_outb(adap
,msg
->addr
& 0x7f);
308 /* Status check comes here */
310 printk(KERN_ERR
"died at 2nd address code.\n");
313 if ( flags
& I2C_M_RD
) {
315 /* okay, now switch into reading mode */
317 ret
= try_address(adap
, addr
, retries
);
319 printk(KERN_ERR
"died at extended address code.\n");
323 } else { /* normal 7bit address */
324 addr
= ( msg
->addr
<< 1 );
325 if (flags
& I2C_M_RD
)
327 if (flags
& I2C_M_REV_DIR_ADDR
)
329 i2c_outb(adap
, addr
);
334 static int pcf_xfer(struct i2c_adapter
*i2c_adap
,
335 struct i2c_msg msgs
[],
338 struct i2c_algo_pcf_data
*adap
= i2c_adap
->algo_data
;
339 struct i2c_msg
*pmsg
;
341 int ret
=0, timeout
, status
;
344 /* Check for bus busy */
345 timeout
= wait_for_bb(adap
);
347 DEB2(printk(KERN_ERR
"i2c-algo-pcf.o: "
348 "Timeout waiting for BB in pcf_xfer\n");)
352 for (i
= 0;ret
>= 0 && i
< num
; i
++) {
355 DEB2(printk(KERN_DEBUG
"i2c-algo-pcf.o: Doing %s %d bytes to 0x%02x - %d of %d messages\n",
356 pmsg
->flags
& I2C_M_RD
? "read" : "write",
357 pmsg
->len
, pmsg
->addr
, i
+ 1, num
);)
359 ret
= pcf_doAddress(adap
, pmsg
, i2c_adap
->retries
);
366 /* Wait for PIN (pending interrupt NOT) */
367 timeout
= wait_for_pin(adap
, &status
);
370 DEB2(printk(KERN_ERR
"i2c-algo-pcf.o: Timeout waiting "
371 "for PIN(1) in pcf_xfer\n");)
376 /* Check LRB (last rcvd bit - slave ack) */
377 if (status
& I2C_PCF_LRB
) {
379 DEB2(printk(KERN_ERR
"i2c-algo-pcf.o: No LRB(1) in pcf_xfer\n");)
384 DEB3(printk(KERN_DEBUG
"i2c-algo-pcf.o: Msg %d, addr=0x%x, flags=0x%x, len=%d\n",
385 i
, msgs
[i
].addr
, msgs
[i
].flags
, msgs
[i
].len
);)
388 if (pmsg
->flags
& I2C_M_RD
) {
389 /* read bytes into buffer*/
390 ret
= pcf_readbytes(i2c_adap
, pmsg
->buf
, pmsg
->len
,
393 if (ret
!= pmsg
->len
) {
394 DEB2(printk(KERN_DEBUG
"i2c-algo-pcf.o: fail: "
395 "only read %d bytes.\n",ret
));
397 DEB2(printk(KERN_DEBUG
"i2c-algo-pcf.o: read %d bytes.\n",ret
));
400 ret
= pcf_sendbytes(i2c_adap
, pmsg
->buf
, pmsg
->len
,
403 if (ret
!= pmsg
->len
) {
404 DEB2(printk(KERN_DEBUG
"i2c-algo-pcf.o: fail: "
405 "only wrote %d bytes.\n",ret
));
407 DEB2(printk(KERN_DEBUG
"i2c-algo-pcf.o: wrote %d bytes.\n",ret
));
415 static u32
pcf_func(struct i2c_adapter
*adap
)
417 return I2C_FUNC_SMBUS_EMUL
| I2C_FUNC_10BIT_ADDR
|
418 I2C_FUNC_PROTOCOL_MANGLING
;
421 /* -----exported algorithm data: ------------------------------------- */
423 static struct i2c_algorithm pcf_algo
= {
424 .name
= "PCF8584 algorithm",
426 .master_xfer
= pcf_xfer
,
427 .functionality
= pcf_func
,
431 * registering functions to load algorithms at runtime
433 int i2c_pcf_add_bus(struct i2c_adapter
*adap
)
435 struct i2c_algo_pcf_data
*pcf_adap
= adap
->algo_data
;
438 DEB2(dev_dbg(&adap
->dev
, "hw routines registered.\n"));
440 /* register new adapter to i2c module... */
442 adap
->id
|= pcf_algo
.id
;
443 adap
->algo
= &pcf_algo
;
445 adap
->timeout
= 100; /* default values, should */
446 adap
->retries
= 3; /* be replaced by defines */
448 rval
= pcf_init_8584(pcf_adap
);
450 i2c_add_adapter(adap
);
455 int i2c_pcf_del_bus(struct i2c_adapter
*adap
)
457 return i2c_del_adapter(adap
);
460 EXPORT_SYMBOL(i2c_pcf_add_bus
);
461 EXPORT_SYMBOL(i2c_pcf_del_bus
);
463 MODULE_AUTHOR("Hans Berglund <hb@spacetec.no>");
464 MODULE_DESCRIPTION("I2C-Bus PCF8584 algorithm");
465 MODULE_LICENSE("GPL");
467 module_param(i2c_debug
, int, S_IRUGO
| S_IWUSR
);
468 MODULE_PARM_DESC(i2c_debug
,
469 "debug level - 0 off; 1 normal; 2,3 more verbose; 9 pcf-protocol");