i2c-algo-pcf: Add adapter hooks around xfer begin and end
[linux-2.6.git] / drivers / i2c / algos / i2c-algo-pcf.c
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
6
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.
11
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.
16
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 /* ------------------------------------------------------------------------- */
21
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> */
25
26 /* Partially rewriten by Oleg I. Vdovikin <vdovikin@jscc.ru> to handle multiple
27    messages, proper stop/repstart signaling during receive,
28    added detect code */
29
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"
39
40
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
46
47 /* module parameters:
48  */
49 static int i2c_debug;
50
51 /* --- setting states on the bus with the right timing: --------------- */
52
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)
59
60 /* --- other auxiliary functions -------------------------------------- */
61
62 static void i2c_start(struct i2c_algo_pcf_data *adap) 
63 {
64         DEBPROTO(printk("S "));
65         set_pcf(adap, 1, I2C_PCF_START);
66 }
67
68 static void i2c_repstart(struct i2c_algo_pcf_data *adap) 
69 {
70         DEBPROTO(printk(" Sr "));
71         set_pcf(adap, 1, I2C_PCF_REPSTART);
72 }
73
74
75 static void i2c_stop(struct i2c_algo_pcf_data *adap) 
76 {
77         DEBPROTO(printk("P\n"));
78         set_pcf(adap, 1, I2C_PCF_STOP);
79 }
80
81 static void handle_lab(struct i2c_algo_pcf_data *adap, const int *status)
82 {
83         DEB2(printk(KERN_INFO
84                 "i2c-algo-pcf.o: lost arbitration (CSR 0x%02x)\n",
85                  *status));
86
87         /* Cleanup from LAB -- reset and enable ESO.
88          * This resets the PCF8584; since we've lost the bus, no
89          * further attempts should be made by callers to clean up
90          * (no i2c_stop() etc.)
91          */
92         set_pcf(adap, 1, I2C_PCF_PIN);
93         set_pcf(adap, 1, I2C_PCF_ESO);
94
95         /* We pause for a time period sufficient for any running
96          * I2C transaction to complete -- the arbitration logic won't
97          * work properly until the next START is seen.
98          * It is assumed the bus driver or client has set a proper value.
99          *
100          * REVISIT: should probably use msleep instead of mdelay if we
101          * know we can sleep.
102          */
103         if (adap->lab_mdelay)
104                 mdelay(adap->lab_mdelay);
105
106         DEB2(printk(KERN_INFO
107                 "i2c-algo-pcf.o: reset LAB condition (CSR 0x%02x)\n",
108                 get_pcf(adap, 1)));
109 }
110
111 static int wait_for_bb(struct i2c_algo_pcf_data *adap) {
112
113         int timeout = DEF_TIMEOUT;
114         int status;
115
116         status = get_pcf(adap, 1);
117 #ifndef STUB_I2C
118         while (timeout-- && !(status & I2C_PCF_BB)) {
119                 udelay(100); /* wait for 100 us */
120                 status = get_pcf(adap, 1);
121         }
122 #endif
123         if (timeout <= 0) {
124                 printk(KERN_ERR "Timeout waiting for Bus Busy\n");
125         }
126         
127         return (timeout<=0);
128 }
129
130
131 static int wait_for_pin(struct i2c_algo_pcf_data *adap, int *status) {
132
133         int timeout = DEF_TIMEOUT;
134
135         *status = get_pcf(adap, 1);
136 #ifndef STUB_I2C
137         while (timeout-- && (*status & I2C_PCF_PIN)) {
138                 adap->waitforpin(adap->data);
139                 *status = get_pcf(adap, 1);
140         }
141         if (*status & I2C_PCF_LAB) {
142                 handle_lab(adap, status);
143                 return(-EINTR);
144         }
145 #endif
146         if (timeout <= 0)
147                 return(-1);
148         else
149                 return(0);
150 }
151
152 /* 
153  * This should perform the 'PCF8584 initialization sequence' as described
154  * in the Philips IC12 data book (1995, Aug 29).
155  * There should be a 30 clock cycle wait after reset, I assume this
156  * has been fulfilled.
157  * There should be a delay at the end equal to the longest I2C message
158  * to synchronize the BB-bit (in multimaster systems). How long is
159  * this? I assume 1 second is always long enough.
160  *
161  * vdovikin: added detect code for PCF8584
162  */
163 static int pcf_init_8584 (struct i2c_algo_pcf_data *adap)
164 {
165         unsigned char temp;
166
167         DEB3(printk(KERN_DEBUG "i2c-algo-pcf.o: PCF state 0x%02x\n", get_pcf(adap, 1)));
168
169         /* S1=0x80: S0 selected, serial interface off */
170         set_pcf(adap, 1, I2C_PCF_PIN);
171         /* check to see S1 now used as R/W ctrl -
172            PCF8584 does that when ESO is zero */
173         if (((temp = get_pcf(adap, 1)) & 0x7f) != (0)) {
174                 DEB2(printk(KERN_ERR "i2c-algo-pcf.o: PCF detection failed -- can't select S0 (0x%02x).\n", temp));
175                 return -ENXIO; /* definetly not PCF8584 */
176         }
177
178         /* load own address in S0, effective address is (own << 1)      */
179         i2c_outb(adap, get_own(adap));
180         /* check it's really written */
181         if ((temp = i2c_inb(adap)) != get_own(adap)) {
182                 DEB2(printk(KERN_ERR "i2c-algo-pcf.o: PCF detection failed -- can't set S0 (0x%02x).\n", temp));
183                 return -ENXIO;
184         }
185
186         /* S1=0xA0, next byte in S2                                     */
187         set_pcf(adap, 1, I2C_PCF_PIN | I2C_PCF_ES1);
188         /* check to see S2 now selected */
189         if (((temp = get_pcf(adap, 1)) & 0x7f) != I2C_PCF_ES1) {
190                 DEB2(printk(KERN_ERR "i2c-algo-pcf.o: PCF detection failed -- can't select S2 (0x%02x).\n", temp));
191                 return -ENXIO;
192         }
193
194         /* load clock register S2                                       */
195         i2c_outb(adap, get_clock(adap));
196         /* check it's really written, the only 5 lowest bits does matter */
197         if (((temp = i2c_inb(adap)) & 0x1f) != get_clock(adap)) {
198                 DEB2(printk(KERN_ERR "i2c-algo-pcf.o: PCF detection failed -- can't set S2 (0x%02x).\n", temp));
199                 return -ENXIO;
200         }
201
202         /* Enable serial interface, idle, S0 selected                   */
203         set_pcf(adap, 1, I2C_PCF_IDLE);
204
205         /* check to see PCF is really idled and we can access status register */
206         if ((temp = get_pcf(adap, 1)) != (I2C_PCF_PIN | I2C_PCF_BB)) {
207                 DEB2(printk(KERN_ERR "i2c-algo-pcf.o: PCF detection failed -- can't select S1` (0x%02x).\n", temp));
208                 return -ENXIO;
209         }
210         
211         printk(KERN_DEBUG "i2c-algo-pcf.o: deteted and initialized PCF8584.\n");
212
213         return 0;
214 }
215
216
217 /* ----- Utility functions
218  */
219
220 static int pcf_sendbytes(struct i2c_adapter *i2c_adap, const char *buf,
221                          int count, int last)
222 {
223         struct i2c_algo_pcf_data *adap = i2c_adap->algo_data;
224         int wrcount, status, timeout;
225     
226         for (wrcount=0; wrcount<count; ++wrcount) {
227                 DEB2(dev_dbg(&i2c_adap->dev, "i2c_write: writing %2.2X\n",
228                                 buf[wrcount]&0xff));
229                 i2c_outb(adap, buf[wrcount]);
230                 timeout = wait_for_pin(adap, &status);
231                 if (timeout) {
232                         if (timeout == -EINTR) {
233                                 /* arbitration lost */
234                                 return -EINTR;
235                         }
236                         i2c_stop(adap);
237                         dev_err(&i2c_adap->dev, "i2c_write: error - timeout.\n");
238                         return -EREMOTEIO; /* got a better one ?? */
239                 }
240 #ifndef STUB_I2C
241                 if (status & I2C_PCF_LRB) {
242                         i2c_stop(adap);
243                         dev_err(&i2c_adap->dev, "i2c_write: error - no ack.\n");
244                         return -EREMOTEIO; /* got a better one ?? */
245                 }
246 #endif
247         }
248         if (last) {
249                 i2c_stop(adap);
250         }
251         else {
252                 i2c_repstart(adap);
253         }
254
255         return (wrcount);
256 }
257
258
259 static int pcf_readbytes(struct i2c_adapter *i2c_adap, char *buf,
260                          int count, int last)
261 {
262         int i, status;
263         struct i2c_algo_pcf_data *adap = i2c_adap->algo_data;
264         int wfp;
265
266         /* increment number of bytes to read by one -- read dummy byte */
267         for (i = 0; i <= count; i++) {
268
269                 if ((wfp = wait_for_pin(adap, &status))) {
270                         if (wfp == -EINTR) {
271                                 /* arbitration lost */
272                                 return -EINTR;
273                         }
274                         i2c_stop(adap);
275                         dev_err(&i2c_adap->dev, "pcf_readbytes timed out.\n");
276                         return (-1);
277                 }
278
279 #ifndef STUB_I2C
280                 if ((status & I2C_PCF_LRB) && (i != count)) {
281                         i2c_stop(adap);
282                         dev_err(&i2c_adap->dev, "i2c_read: i2c_inb, No ack.\n");
283                         return (-1);
284                 }
285 #endif
286                 
287                 if (i == count - 1) {
288                         set_pcf(adap, 1, I2C_PCF_ESO);
289                 } else 
290                 if (i == count) {
291                         if (last) {
292                                 i2c_stop(adap);
293                         } else {
294                                 i2c_repstart(adap);
295                         }
296                 };
297
298                 if (i) {
299                         buf[i - 1] = i2c_inb(adap);
300                 } else {
301                         i2c_inb(adap); /* dummy read */
302                 }
303         }
304
305         return (i - 1);
306 }
307
308
309 static int pcf_doAddress(struct i2c_algo_pcf_data *adap,
310                          struct i2c_msg *msg)
311 {
312         unsigned short flags = msg->flags;
313         unsigned char addr;
314
315         addr = msg->addr << 1;
316         if (flags & I2C_M_RD)
317                 addr |= 1;
318         if (flags & I2C_M_REV_DIR_ADDR)
319                 addr ^= 1;
320         i2c_outb(adap, addr);
321
322         return 0;
323 }
324
325 static int pcf_xfer(struct i2c_adapter *i2c_adap,
326                     struct i2c_msg *msgs, 
327                     int num)
328 {
329         struct i2c_algo_pcf_data *adap = i2c_adap->algo_data;
330         struct i2c_msg *pmsg;
331         int i;
332         int ret=0, timeout, status;
333     
334         if (adap->xfer_begin)
335                 adap->xfer_begin(adap->data);
336
337         /* Check for bus busy */
338         timeout = wait_for_bb(adap);
339         if (timeout) {
340                 DEB2(printk(KERN_ERR "i2c-algo-pcf.o: "
341                             "Timeout waiting for BB in pcf_xfer\n");)
342                 i = -EIO;
343                 goto out;
344         }
345         
346         for (i = 0;ret >= 0 && i < num; i++) {
347                 pmsg = &msgs[i];
348
349                 DEB2(printk(KERN_DEBUG "i2c-algo-pcf.o: Doing %s %d bytes to 0x%02x - %d of %d messages\n",
350                      pmsg->flags & I2C_M_RD ? "read" : "write",
351                      pmsg->len, pmsg->addr, i + 1, num);)
352     
353                 ret = pcf_doAddress(adap, pmsg);
354
355                 /* Send START */
356                 if (i == 0) {
357                         i2c_start(adap); 
358                 }
359     
360                 /* Wait for PIN (pending interrupt NOT) */
361                 timeout = wait_for_pin(adap, &status);
362                 if (timeout) {
363                         if (timeout == -EINTR) {
364                                 /* arbitration lost */
365                                 i = -EINTR;
366                                 goto out;
367                         }
368                         i2c_stop(adap);
369                         DEB2(printk(KERN_ERR "i2c-algo-pcf.o: Timeout waiting "
370                                     "for PIN(1) in pcf_xfer\n");)
371                         i = -EREMOTEIO;
372                         goto out;
373                 }
374     
375 #ifndef STUB_I2C
376                 /* Check LRB (last rcvd bit - slave ack) */
377                 if (status & I2C_PCF_LRB) {
378                         i2c_stop(adap);
379                         DEB2(printk(KERN_ERR "i2c-algo-pcf.o: No LRB(1) in pcf_xfer\n");)
380                         i = -EREMOTEIO;
381                         goto out;
382                 }
383 #endif
384     
385                 DEB3(printk(KERN_DEBUG "i2c-algo-pcf.o: Msg %d, addr=0x%x, flags=0x%x, len=%d\n",
386                             i, msgs[i].addr, msgs[i].flags, msgs[i].len);)
387     
388                 /* Read */
389                 if (pmsg->flags & I2C_M_RD) {
390                         /* read bytes into buffer*/
391                         ret = pcf_readbytes(i2c_adap, pmsg->buf, pmsg->len,
392                                             (i + 1 == num));
393         
394                         if (ret != pmsg->len) {
395                                 DEB2(printk(KERN_DEBUG "i2c-algo-pcf.o: fail: "
396                                             "only read %d bytes.\n",ret));
397                         } else {
398                                 DEB2(printk(KERN_DEBUG "i2c-algo-pcf.o: read %d bytes.\n",ret));
399                         }
400                 } else { /* Write */
401                         ret = pcf_sendbytes(i2c_adap, pmsg->buf, pmsg->len,
402                                             (i + 1 == num));
403         
404                         if (ret != pmsg->len) {
405                                 DEB2(printk(KERN_DEBUG "i2c-algo-pcf.o: fail: "
406                                             "only wrote %d bytes.\n",ret));
407                         } else {
408                                 DEB2(printk(KERN_DEBUG "i2c-algo-pcf.o: wrote %d bytes.\n",ret));
409                         }
410                 }
411         }
412
413 out:
414         if (adap->xfer_end)
415                 adap->xfer_end(adap->data);
416         return (i);
417 }
418
419 static u32 pcf_func(struct i2c_adapter *adap)
420 {
421         return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | 
422                I2C_FUNC_PROTOCOL_MANGLING;
423 }
424
425 /* -----exported algorithm data: -------------------------------------  */
426
427 static const struct i2c_algorithm pcf_algo = {
428         .master_xfer    = pcf_xfer,
429         .functionality  = pcf_func,
430 };
431
432 /* 
433  * registering functions to load algorithms at runtime 
434  */
435 int i2c_pcf_add_bus(struct i2c_adapter *adap)
436 {
437         struct i2c_algo_pcf_data *pcf_adap = adap->algo_data;
438         int rval;
439
440         DEB2(dev_dbg(&adap->dev, "hw routines registered.\n"));
441
442         /* register new adapter to i2c module... */
443         adap->algo = &pcf_algo;
444         adap->timeout = 100;
445
446         if ((rval = pcf_init_8584(pcf_adap)))
447                 return rval;
448
449         rval = i2c_add_adapter(adap);
450
451         return rval;
452 }
453 EXPORT_SYMBOL(i2c_pcf_add_bus);
454
455 MODULE_AUTHOR("Hans Berglund <hb@spacetec.no>");
456 MODULE_DESCRIPTION("I2C-Bus PCF8584 algorithm");
457 MODULE_LICENSE("GPL");
458
459 module_param(i2c_debug, int, S_IRUGO | S_IWUSR);
460 MODULE_PARM_DESC(i2c_debug,
461         "debug level - 0 off; 1 normal; 2,3 more verbose; 9 pcf-protocol");