Commit | Line | Data |
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0c168ceb RK |
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 | |
5694f8a8 JD |
19 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, |
20 | * MA 02110-1301 USA. | |
0c168ceb RK |
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, added detect code | |
28 | */ | |
1da177e4 LT |
29 | |
30 | #include <linux/kernel.h> | |
31 | #include <linux/module.h> | |
32 | #include <linux/delay.h> | |
1da177e4 LT |
33 | #include <linux/init.h> |
34 | #include <linux/errno.h> | |
35 | #include <linux/i2c.h> | |
36 | #include <linux/i2c-algo-pcf.h> | |
37 | #include "i2c-algo-pcf.h" | |
38 | ||
39 | ||
0c168ceb RK |
40 | #define DEB2(x) if (i2c_debug >= 2) x |
41 | #define DEB3(x) if (i2c_debug >= 3) x /* print several statistical values */ | |
42 | #define DEBPROTO(x) if (i2c_debug >= 9) x; | |
43 | /* debug the protocol by showing transferred bits */ | |
1da177e4 LT |
44 | #define DEF_TIMEOUT 16 |
45 | ||
0c168ceb RK |
46 | /* |
47 | * module parameters: | |
1da177e4 LT |
48 | */ |
49 | static int i2c_debug; | |
50 | ||
0c168ceb | 51 | /* setting states on the bus with the right timing: */ |
1da177e4 LT |
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 | ||
0c168ceb | 60 | /* other auxiliary functions */ |
1da177e4 | 61 | |
0c168ceb | 62 | static void i2c_start(struct i2c_algo_pcf_data *adap) |
1da177e4 | 63 | { |
154d22b0 | 64 | DEBPROTO(printk(KERN_DEBUG "S ")); |
1da177e4 LT |
65 | set_pcf(adap, 1, I2C_PCF_START); |
66 | } | |
67 | ||
0c168ceb | 68 | static void i2c_repstart(struct i2c_algo_pcf_data *adap) |
1da177e4 LT |
69 | { |
70 | DEBPROTO(printk(" Sr ")); | |
71 | set_pcf(adap, 1, I2C_PCF_REPSTART); | |
72 | } | |
73 | ||
0c168ceb | 74 | static void i2c_stop(struct i2c_algo_pcf_data *adap) |
1da177e4 LT |
75 | { |
76 | DEBPROTO(printk("P\n")); | |
77 | set_pcf(adap, 1, I2C_PCF_STOP); | |
78 | } | |
79 | ||
0573d11b EB |
80 | static void handle_lab(struct i2c_algo_pcf_data *adap, const int *status) |
81 | { | |
82 | DEB2(printk(KERN_INFO | |
83 | "i2c-algo-pcf.o: lost arbitration (CSR 0x%02x)\n", | |
0c168ceb RK |
84 | *status)); |
85 | /* | |
86 | * Cleanup from LAB -- reset and enable ESO. | |
0573d11b EB |
87 | * This resets the PCF8584; since we've lost the bus, no |
88 | * further attempts should be made by callers to clean up | |
89 | * (no i2c_stop() etc.) | |
90 | */ | |
91 | set_pcf(adap, 1, I2C_PCF_PIN); | |
92 | set_pcf(adap, 1, I2C_PCF_ESO); | |
0c168ceb RK |
93 | /* |
94 | * We pause for a time period sufficient for any running | |
0573d11b EB |
95 | * I2C transaction to complete -- the arbitration logic won't |
96 | * work properly until the next START is seen. | |
97 | * It is assumed the bus driver or client has set a proper value. | |
98 | * | |
99 | * REVISIT: should probably use msleep instead of mdelay if we | |
100 | * know we can sleep. | |
101 | */ | |
102 | if (adap->lab_mdelay) | |
103 | mdelay(adap->lab_mdelay); | |
104 | ||
105 | DEB2(printk(KERN_INFO | |
106 | "i2c-algo-pcf.o: reset LAB condition (CSR 0x%02x)\n", | |
107 | get_pcf(adap, 1))); | |
108 | } | |
109 | ||
0c168ceb RK |
110 | static int wait_for_bb(struct i2c_algo_pcf_data *adap) |
111 | { | |
1da177e4 LT |
112 | |
113 | int timeout = DEF_TIMEOUT; | |
114 | int status; | |
115 | ||
116 | status = get_pcf(adap, 1); | |
0c168ceb | 117 | |
94d78e18 | 118 | while (!(status & I2C_PCF_BB) && --timeout) { |
1da177e4 LT |
119 | udelay(100); /* wait for 100 us */ |
120 | status = get_pcf(adap, 1); | |
121 | } | |
0c168ceb | 122 | |
94d78e18 | 123 | if (timeout == 0) { |
1da177e4 | 124 | printk(KERN_ERR "Timeout waiting for Bus Busy\n"); |
94d78e18 RK |
125 | return -ETIMEDOUT; |
126 | } | |
1da177e4 | 127 | |
94d78e18 | 128 | return 0; |
0c168ceb | 129 | } |
1da177e4 | 130 | |
0c168ceb RK |
131 | static int wait_for_pin(struct i2c_algo_pcf_data *adap, int *status) |
132 | { | |
1da177e4 LT |
133 | |
134 | int timeout = DEF_TIMEOUT; | |
135 | ||
136 | *status = get_pcf(adap, 1); | |
0c168ceb | 137 | |
94d78e18 | 138 | while ((*status & I2C_PCF_PIN) && --timeout) { |
08e5338d | 139 | adap->waitforpin(adap->data); |
1da177e4 LT |
140 | *status = get_pcf(adap, 1); |
141 | } | |
142 | if (*status & I2C_PCF_LAB) { | |
0573d11b | 143 | handle_lab(adap, status); |
0c168ceb | 144 | return -EINTR; |
1da177e4 | 145 | } |
0c168ceb | 146 | |
94d78e18 RK |
147 | if (timeout == 0) |
148 | return -ETIMEDOUT; | |
149 | ||
150 | return 0; | |
1da177e4 LT |
151 | } |
152 | ||
0c168ceb | 153 | /* |
1da177e4 LT |
154 | * This should perform the 'PCF8584 initialization sequence' as described |
155 | * in the Philips IC12 data book (1995, Aug 29). | |
156 | * There should be a 30 clock cycle wait after reset, I assume this | |
157 | * has been fulfilled. | |
158 | * There should be a delay at the end equal to the longest I2C message | |
159 | * to synchronize the BB-bit (in multimaster systems). How long is | |
160 | * this? I assume 1 second is always long enough. | |
161 | * | |
162 | * vdovikin: added detect code for PCF8584 | |
163 | */ | |
164 | static int pcf_init_8584 (struct i2c_algo_pcf_data *adap) | |
165 | { | |
166 | unsigned char temp; | |
167 | ||
0c168ceb RK |
168 | DEB3(printk(KERN_DEBUG "i2c-algo-pcf.o: PCF state 0x%02x\n", |
169 | get_pcf(adap, 1))); | |
1da177e4 LT |
170 | |
171 | /* S1=0x80: S0 selected, serial interface off */ | |
172 | set_pcf(adap, 1, I2C_PCF_PIN); | |
0c168ceb RK |
173 | /* |
174 | * check to see S1 now used as R/W ctrl - | |
175 | * PCF8584 does that when ESO is zero | |
176 | */ | |
1da177e4 LT |
177 | if (((temp = get_pcf(adap, 1)) & 0x7f) != (0)) { |
178 | DEB2(printk(KERN_ERR "i2c-algo-pcf.o: PCF detection failed -- can't select S0 (0x%02x).\n", temp)); | |
7d9b48ea | 179 | return -ENXIO; /* definitely not PCF8584 */ |
1da177e4 LT |
180 | } |
181 | ||
0c168ceb | 182 | /* load own address in S0, effective address is (own << 1) */ |
1da177e4 LT |
183 | i2c_outb(adap, get_own(adap)); |
184 | /* check it's really written */ | |
185 | if ((temp = i2c_inb(adap)) != get_own(adap)) { | |
186 | DEB2(printk(KERN_ERR "i2c-algo-pcf.o: PCF detection failed -- can't set S0 (0x%02x).\n", temp)); | |
187 | return -ENXIO; | |
188 | } | |
189 | ||
0c168ceb | 190 | /* S1=0xA0, next byte in S2 */ |
1da177e4 LT |
191 | set_pcf(adap, 1, I2C_PCF_PIN | I2C_PCF_ES1); |
192 | /* check to see S2 now selected */ | |
193 | if (((temp = get_pcf(adap, 1)) & 0x7f) != I2C_PCF_ES1) { | |
194 | DEB2(printk(KERN_ERR "i2c-algo-pcf.o: PCF detection failed -- can't select S2 (0x%02x).\n", temp)); | |
195 | return -ENXIO; | |
196 | } | |
197 | ||
0c168ceb | 198 | /* load clock register S2 */ |
1da177e4 LT |
199 | i2c_outb(adap, get_clock(adap)); |
200 | /* check it's really written, the only 5 lowest bits does matter */ | |
201 | if (((temp = i2c_inb(adap)) & 0x1f) != get_clock(adap)) { | |
202 | DEB2(printk(KERN_ERR "i2c-algo-pcf.o: PCF detection failed -- can't set S2 (0x%02x).\n", temp)); | |
203 | return -ENXIO; | |
204 | } | |
205 | ||
0c168ceb | 206 | /* Enable serial interface, idle, S0 selected */ |
1da177e4 LT |
207 | set_pcf(adap, 1, I2C_PCF_IDLE); |
208 | ||
209 | /* check to see PCF is really idled and we can access status register */ | |
210 | if ((temp = get_pcf(adap, 1)) != (I2C_PCF_PIN | I2C_PCF_BB)) { | |
211 | DEB2(printk(KERN_ERR "i2c-algo-pcf.o: PCF detection failed -- can't select S1` (0x%02x).\n", temp)); | |
212 | return -ENXIO; | |
213 | } | |
0c168ceb | 214 | |
a672b4c1 | 215 | printk(KERN_DEBUG "i2c-algo-pcf.o: detected and initialized PCF8584.\n"); |
1da177e4 LT |
216 | |
217 | return 0; | |
218 | } | |
219 | ||
1da177e4 | 220 | static int pcf_sendbytes(struct i2c_adapter *i2c_adap, const char *buf, |
0c168ceb | 221 | int count, int last) |
1da177e4 LT |
222 | { |
223 | struct i2c_algo_pcf_data *adap = i2c_adap->algo_data; | |
224 | int wrcount, status, timeout; | |
0c168ceb | 225 | |
1da177e4 LT |
226 | for (wrcount=0; wrcount<count; ++wrcount) { |
227 | DEB2(dev_dbg(&i2c_adap->dev, "i2c_write: writing %2.2X\n", | |
0c168ceb | 228 | buf[wrcount] & 0xff)); |
1da177e4 LT |
229 | i2c_outb(adap, buf[wrcount]); |
230 | timeout = wait_for_pin(adap, &status); | |
231 | if (timeout) { | |
0c168ceb RK |
232 | if (timeout == -EINTR) |
233 | return -EINTR; /* arbitration lost */ | |
234 | ||
1da177e4 LT |
235 | i2c_stop(adap); |
236 | dev_err(&i2c_adap->dev, "i2c_write: error - timeout.\n"); | |
237 | return -EREMOTEIO; /* got a better one ?? */ | |
238 | } | |
1da177e4 LT |
239 | if (status & I2C_PCF_LRB) { |
240 | i2c_stop(adap); | |
241 | dev_err(&i2c_adap->dev, "i2c_write: error - no ack.\n"); | |
242 | return -EREMOTEIO; /* got a better one ?? */ | |
243 | } | |
1da177e4 | 244 | } |
0c168ceb | 245 | if (last) |
1da177e4 | 246 | i2c_stop(adap); |
0c168ceb | 247 | else |
1da177e4 | 248 | i2c_repstart(adap); |
1da177e4 | 249 | |
0c168ceb | 250 | return wrcount; |
1da177e4 LT |
251 | } |
252 | ||
1da177e4 | 253 | static int pcf_readbytes(struct i2c_adapter *i2c_adap, char *buf, |
0c168ceb | 254 | int count, int last) |
1da177e4 LT |
255 | { |
256 | int i, status; | |
257 | struct i2c_algo_pcf_data *adap = i2c_adap->algo_data; | |
258 | int wfp; | |
259 | ||
260 | /* increment number of bytes to read by one -- read dummy byte */ | |
261 | for (i = 0; i <= count; i++) { | |
262 | ||
263 | if ((wfp = wait_for_pin(adap, &status))) { | |
0c168ceb RK |
264 | if (wfp == -EINTR) |
265 | return -EINTR; /* arbitration lost */ | |
266 | ||
1da177e4 LT |
267 | i2c_stop(adap); |
268 | dev_err(&i2c_adap->dev, "pcf_readbytes timed out.\n"); | |
0c168ceb | 269 | return -1; |
1da177e4 LT |
270 | } |
271 | ||
1da177e4 LT |
272 | if ((status & I2C_PCF_LRB) && (i != count)) { |
273 | i2c_stop(adap); | |
274 | dev_err(&i2c_adap->dev, "i2c_read: i2c_inb, No ack.\n"); | |
0c168ceb | 275 | return -1; |
1da177e4 | 276 | } |
0c168ceb | 277 | |
1da177e4 LT |
278 | if (i == count - 1) { |
279 | set_pcf(adap, 1, I2C_PCF_ESO); | |
0c168ceb RK |
280 | } else if (i == count) { |
281 | if (last) | |
1da177e4 | 282 | i2c_stop(adap); |
0c168ceb | 283 | else |
1da177e4 | 284 | i2c_repstart(adap); |
0c168ceb | 285 | } |
1da177e4 | 286 | |
0c168ceb | 287 | if (i) |
1da177e4 | 288 | buf[i - 1] = i2c_inb(adap); |
0c168ceb | 289 | else |
1da177e4 | 290 | i2c_inb(adap); /* dummy read */ |
1da177e4 LT |
291 | } |
292 | ||
0c168ceb | 293 | return i - 1; |
1da177e4 LT |
294 | } |
295 | ||
296 | ||
6408a833 JD |
297 | static int pcf_doAddress(struct i2c_algo_pcf_data *adap, |
298 | struct i2c_msg *msg) | |
1da177e4 LT |
299 | { |
300 | unsigned short flags = msg->flags; | |
301 | unsigned char addr; | |
6408a833 JD |
302 | |
303 | addr = msg->addr << 1; | |
304 | if (flags & I2C_M_RD) | |
305 | addr |= 1; | |
306 | if (flags & I2C_M_REV_DIR_ADDR) | |
307 | addr ^= 1; | |
308 | i2c_outb(adap, addr); | |
309 | ||
1da177e4 LT |
310 | return 0; |
311 | } | |
312 | ||
313 | static int pcf_xfer(struct i2c_adapter *i2c_adap, | |
0c168ceb | 314 | struct i2c_msg *msgs, |
1da177e4 LT |
315 | int num) |
316 | { | |
317 | struct i2c_algo_pcf_data *adap = i2c_adap->algo_data; | |
318 | struct i2c_msg *pmsg; | |
319 | int i; | |
320 | int ret=0, timeout, status; | |
0c168ceb | 321 | |
30091404 DM |
322 | if (adap->xfer_begin) |
323 | adap->xfer_begin(adap->data); | |
1da177e4 LT |
324 | |
325 | /* Check for bus busy */ | |
326 | timeout = wait_for_bb(adap); | |
327 | if (timeout) { | |
328 | DEB2(printk(KERN_ERR "i2c-algo-pcf.o: " | |
0c168ceb | 329 | "Timeout waiting for BB in pcf_xfer\n");) |
30091404 DM |
330 | i = -EIO; |
331 | goto out; | |
1da177e4 | 332 | } |
0c168ceb | 333 | |
1da177e4 LT |
334 | for (i = 0;ret >= 0 && i < num; i++) { |
335 | pmsg = &msgs[i]; | |
336 | ||
337 | DEB2(printk(KERN_DEBUG "i2c-algo-pcf.o: Doing %s %d bytes to 0x%02x - %d of %d messages\n", | |
338 | pmsg->flags & I2C_M_RD ? "read" : "write", | |
0c168ceb RK |
339 | pmsg->len, pmsg->addr, i + 1, num);) |
340 | ||
6408a833 | 341 | ret = pcf_doAddress(adap, pmsg); |
1da177e4 LT |
342 | |
343 | /* Send START */ | |
0c168ceb RK |
344 | if (i == 0) |
345 | i2c_start(adap); | |
346 | ||
1da177e4 LT |
347 | /* Wait for PIN (pending interrupt NOT) */ |
348 | timeout = wait_for_pin(adap, &status); | |
349 | if (timeout) { | |
350 | if (timeout == -EINTR) { | |
351 | /* arbitration lost */ | |
30091404 DM |
352 | i = -EINTR; |
353 | goto out; | |
1da177e4 LT |
354 | } |
355 | i2c_stop(adap); | |
356 | DEB2(printk(KERN_ERR "i2c-algo-pcf.o: Timeout waiting " | |
357 | "for PIN(1) in pcf_xfer\n");) | |
30091404 DM |
358 | i = -EREMOTEIO; |
359 | goto out; | |
1da177e4 | 360 | } |
0c168ceb | 361 | |
1da177e4 LT |
362 | /* Check LRB (last rcvd bit - slave ack) */ |
363 | if (status & I2C_PCF_LRB) { | |
364 | i2c_stop(adap); | |
365 | DEB2(printk(KERN_ERR "i2c-algo-pcf.o: No LRB(1) in pcf_xfer\n");) | |
30091404 DM |
366 | i = -EREMOTEIO; |
367 | goto out; | |
1da177e4 | 368 | } |
0c168ceb | 369 | |
1da177e4 LT |
370 | DEB3(printk(KERN_DEBUG "i2c-algo-pcf.o: Msg %d, addr=0x%x, flags=0x%x, len=%d\n", |
371 | i, msgs[i].addr, msgs[i].flags, msgs[i].len);) | |
0c168ceb | 372 | |
1da177e4 | 373 | if (pmsg->flags & I2C_M_RD) { |
1da177e4 | 374 | ret = pcf_readbytes(i2c_adap, pmsg->buf, pmsg->len, |
0c168ceb RK |
375 | (i + 1 == num)); |
376 | ||
1da177e4 LT |
377 | if (ret != pmsg->len) { |
378 | DEB2(printk(KERN_DEBUG "i2c-algo-pcf.o: fail: " | |
379 | "only read %d bytes.\n",ret)); | |
380 | } else { | |
381 | DEB2(printk(KERN_DEBUG "i2c-algo-pcf.o: read %d bytes.\n",ret)); | |
382 | } | |
0c168ceb | 383 | } else { |
1da177e4 | 384 | ret = pcf_sendbytes(i2c_adap, pmsg->buf, pmsg->len, |
0c168ceb RK |
385 | (i + 1 == num)); |
386 | ||
1da177e4 LT |
387 | if (ret != pmsg->len) { |
388 | DEB2(printk(KERN_DEBUG "i2c-algo-pcf.o: fail: " | |
389 | "only wrote %d bytes.\n",ret)); | |
390 | } else { | |
391 | DEB2(printk(KERN_DEBUG "i2c-algo-pcf.o: wrote %d bytes.\n",ret)); | |
392 | } | |
393 | } | |
394 | } | |
395 | ||
30091404 DM |
396 | out: |
397 | if (adap->xfer_end) | |
398 | adap->xfer_end(adap->data); | |
0c168ceb | 399 | return i; |
1da177e4 LT |
400 | } |
401 | ||
402 | static u32 pcf_func(struct i2c_adapter *adap) | |
403 | { | |
0c168ceb | 404 | return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | |
6408a833 | 405 | I2C_FUNC_PROTOCOL_MANGLING; |
1da177e4 LT |
406 | } |
407 | ||
0c168ceb | 408 | /* exported algorithm data: */ |
9e11a9fb | 409 | static const struct i2c_algorithm pcf_algo = { |
1da177e4 LT |
410 | .master_xfer = pcf_xfer, |
411 | .functionality = pcf_func, | |
412 | }; | |
413 | ||
0c168ceb RK |
414 | /* |
415 | * registering functions to load algorithms at runtime | |
1da177e4 LT |
416 | */ |
417 | int i2c_pcf_add_bus(struct i2c_adapter *adap) | |
418 | { | |
419 | struct i2c_algo_pcf_data *pcf_adap = adap->algo_data; | |
420 | int rval; | |
421 | ||
422 | DEB2(dev_dbg(&adap->dev, "hw routines registered.\n")); | |
423 | ||
424 | /* register new adapter to i2c module... */ | |
1da177e4 | 425 | adap->algo = &pcf_algo; |
1da177e4 | 426 | |
b39ad0cf MH |
427 | if ((rval = pcf_init_8584(pcf_adap))) |
428 | return rval; | |
429 | ||
430 | rval = i2c_add_adapter(adap); | |
431 | ||
1da177e4 LT |
432 | return rval; |
433 | } | |
1da177e4 | 434 | EXPORT_SYMBOL(i2c_pcf_add_bus); |
1da177e4 LT |
435 | |
436 | MODULE_AUTHOR("Hans Berglund <hb@spacetec.no>"); | |
437 | MODULE_DESCRIPTION("I2C-Bus PCF8584 algorithm"); | |
438 | MODULE_LICENSE("GPL"); | |
439 | ||
440 | module_param(i2c_debug, int, S_IRUGO | S_IWUSR); | |
441 | MODULE_PARM_DESC(i2c_debug, | |
0c168ceb | 442 | "debug level - 0 off; 1 normal; 2,3 more verbose; 9 pcf-protocol"); |