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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 | |
19 | * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. | |
20 | * | |
21 | * With some changes from Kyösti Mälkki <kmalkki@cc.hut.fi> and | |
22 | * Frodo Looijaard <frodol@dds.nl>, and also from Martin Bailey | |
23 | * <mbailey@littlefeet-inc.com> | |
24 | * | |
25 | * Partially rewriten by Oleg I. Vdovikin <vdovikin@jscc.ru> to handle multiple | |
26 | * messages, proper stop/repstart signaling during receive, added detect code | |
27 | */ | |
1da177e4 LT |
28 | |
29 | #include <linux/kernel.h> | |
30 | #include <linux/module.h> | |
31 | #include <linux/delay.h> | |
1da177e4 LT |
32 | #include <linux/init.h> |
33 | #include <linux/errno.h> | |
34 | #include <linux/i2c.h> | |
35 | #include <linux/i2c-algo-pcf.h> | |
36 | #include "i2c-algo-pcf.h" | |
37 | ||
38 | ||
0c168ceb RK |
39 | #define DEB2(x) if (i2c_debug >= 2) x |
40 | #define DEB3(x) if (i2c_debug >= 3) x /* print several statistical values */ | |
41 | #define DEBPROTO(x) if (i2c_debug >= 9) x; | |
42 | /* debug the protocol by showing transferred bits */ | |
1da177e4 LT |
43 | #define DEF_TIMEOUT 16 |
44 | ||
0c168ceb RK |
45 | /* |
46 | * module parameters: | |
1da177e4 LT |
47 | */ |
48 | static int i2c_debug; | |
49 | ||
0c168ceb | 50 | /* setting states on the bus with the right timing: */ |
1da177e4 LT |
51 | |
52 | #define set_pcf(adap, ctl, val) adap->setpcf(adap->data, ctl, val) | |
53 | #define get_pcf(adap, ctl) adap->getpcf(adap->data, ctl) | |
54 | #define get_own(adap) adap->getown(adap->data) | |
55 | #define get_clock(adap) adap->getclock(adap->data) | |
56 | #define i2c_outb(adap, val) adap->setpcf(adap->data, 0, val) | |
57 | #define i2c_inb(adap) adap->getpcf(adap->data, 0) | |
58 | ||
0c168ceb | 59 | /* other auxiliary functions */ |
1da177e4 | 60 | |
0c168ceb | 61 | static void i2c_start(struct i2c_algo_pcf_data *adap) |
1da177e4 | 62 | { |
154d22b0 | 63 | DEBPROTO(printk(KERN_DEBUG "S ")); |
1da177e4 LT |
64 | set_pcf(adap, 1, I2C_PCF_START); |
65 | } | |
66 | ||
0c168ceb | 67 | static void i2c_repstart(struct i2c_algo_pcf_data *adap) |
1da177e4 LT |
68 | { |
69 | DEBPROTO(printk(" Sr ")); | |
70 | set_pcf(adap, 1, I2C_PCF_REPSTART); | |
71 | } | |
72 | ||
0c168ceb | 73 | static void i2c_stop(struct i2c_algo_pcf_data *adap) |
1da177e4 LT |
74 | { |
75 | DEBPROTO(printk("P\n")); | |
76 | set_pcf(adap, 1, I2C_PCF_STOP); | |
77 | } | |
78 | ||
0573d11b EB |
79 | static void handle_lab(struct i2c_algo_pcf_data *adap, const int *status) |
80 | { | |
81 | DEB2(printk(KERN_INFO | |
82 | "i2c-algo-pcf.o: lost arbitration (CSR 0x%02x)\n", | |
0c168ceb RK |
83 | *status)); |
84 | /* | |
85 | * Cleanup from LAB -- reset and enable ESO. | |
0573d11b EB |
86 | * This resets the PCF8584; since we've lost the bus, no |
87 | * further attempts should be made by callers to clean up | |
88 | * (no i2c_stop() etc.) | |
89 | */ | |
90 | set_pcf(adap, 1, I2C_PCF_PIN); | |
91 | set_pcf(adap, 1, I2C_PCF_ESO); | |
0c168ceb RK |
92 | /* |
93 | * We pause for a time period sufficient for any running | |
0573d11b EB |
94 | * I2C transaction to complete -- the arbitration logic won't |
95 | * work properly until the next START is seen. | |
96 | * It is assumed the bus driver or client has set a proper value. | |
97 | * | |
98 | * REVISIT: should probably use msleep instead of mdelay if we | |
99 | * know we can sleep. | |
100 | */ | |
101 | if (adap->lab_mdelay) | |
102 | mdelay(adap->lab_mdelay); | |
103 | ||
104 | DEB2(printk(KERN_INFO | |
105 | "i2c-algo-pcf.o: reset LAB condition (CSR 0x%02x)\n", | |
106 | get_pcf(adap, 1))); | |
107 | } | |
108 | ||
0c168ceb RK |
109 | static int wait_for_bb(struct i2c_algo_pcf_data *adap) |
110 | { | |
1da177e4 LT |
111 | |
112 | int timeout = DEF_TIMEOUT; | |
113 | int status; | |
114 | ||
115 | status = get_pcf(adap, 1); | |
0c168ceb | 116 | |
94d78e18 | 117 | while (!(status & I2C_PCF_BB) && --timeout) { |
1da177e4 LT |
118 | udelay(100); /* wait for 100 us */ |
119 | status = get_pcf(adap, 1); | |
120 | } | |
0c168ceb | 121 | |
94d78e18 | 122 | if (timeout == 0) { |
1da177e4 | 123 | printk(KERN_ERR "Timeout waiting for Bus Busy\n"); |
94d78e18 RK |
124 | return -ETIMEDOUT; |
125 | } | |
1da177e4 | 126 | |
94d78e18 | 127 | return 0; |
0c168ceb | 128 | } |
1da177e4 | 129 | |
0c168ceb RK |
130 | static int wait_for_pin(struct i2c_algo_pcf_data *adap, int *status) |
131 | { | |
1da177e4 LT |
132 | |
133 | int timeout = DEF_TIMEOUT; | |
134 | ||
135 | *status = get_pcf(adap, 1); | |
0c168ceb | 136 | |
94d78e18 | 137 | while ((*status & I2C_PCF_PIN) && --timeout) { |
08e5338d | 138 | adap->waitforpin(adap->data); |
1da177e4 LT |
139 | *status = get_pcf(adap, 1); |
140 | } | |
141 | if (*status & I2C_PCF_LAB) { | |
0573d11b | 142 | handle_lab(adap, status); |
0c168ceb | 143 | return -EINTR; |
1da177e4 | 144 | } |
0c168ceb | 145 | |
94d78e18 RK |
146 | if (timeout == 0) |
147 | return -ETIMEDOUT; | |
148 | ||
149 | return 0; | |
1da177e4 LT |
150 | } |
151 | ||
0c168ceb | 152 | /* |
1da177e4 LT |
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 | ||
0c168ceb RK |
167 | DEB3(printk(KERN_DEBUG "i2c-algo-pcf.o: PCF state 0x%02x\n", |
168 | get_pcf(adap, 1))); | |
1da177e4 LT |
169 | |
170 | /* S1=0x80: S0 selected, serial interface off */ | |
171 | set_pcf(adap, 1, I2C_PCF_PIN); | |
0c168ceb RK |
172 | /* |
173 | * check to see S1 now used as R/W ctrl - | |
174 | * PCF8584 does that when ESO is zero | |
175 | */ | |
1da177e4 LT |
176 | if (((temp = get_pcf(adap, 1)) & 0x7f) != (0)) { |
177 | DEB2(printk(KERN_ERR "i2c-algo-pcf.o: PCF detection failed -- can't select S0 (0x%02x).\n", temp)); | |
7d9b48ea | 178 | return -ENXIO; /* definitely not PCF8584 */ |
1da177e4 LT |
179 | } |
180 | ||
0c168ceb | 181 | /* load own address in S0, effective address is (own << 1) */ |
1da177e4 LT |
182 | i2c_outb(adap, get_own(adap)); |
183 | /* check it's really written */ | |
184 | if ((temp = i2c_inb(adap)) != get_own(adap)) { | |
185 | DEB2(printk(KERN_ERR "i2c-algo-pcf.o: PCF detection failed -- can't set S0 (0x%02x).\n", temp)); | |
186 | return -ENXIO; | |
187 | } | |
188 | ||
0c168ceb | 189 | /* S1=0xA0, next byte in S2 */ |
1da177e4 LT |
190 | set_pcf(adap, 1, I2C_PCF_PIN | I2C_PCF_ES1); |
191 | /* check to see S2 now selected */ | |
192 | if (((temp = get_pcf(adap, 1)) & 0x7f) != I2C_PCF_ES1) { | |
193 | DEB2(printk(KERN_ERR "i2c-algo-pcf.o: PCF detection failed -- can't select S2 (0x%02x).\n", temp)); | |
194 | return -ENXIO; | |
195 | } | |
196 | ||
0c168ceb | 197 | /* load clock register S2 */ |
1da177e4 LT |
198 | i2c_outb(adap, get_clock(adap)); |
199 | /* check it's really written, the only 5 lowest bits does matter */ | |
200 | if (((temp = i2c_inb(adap)) & 0x1f) != get_clock(adap)) { | |
201 | DEB2(printk(KERN_ERR "i2c-algo-pcf.o: PCF detection failed -- can't set S2 (0x%02x).\n", temp)); | |
202 | return -ENXIO; | |
203 | } | |
204 | ||
0c168ceb | 205 | /* Enable serial interface, idle, S0 selected */ |
1da177e4 LT |
206 | set_pcf(adap, 1, I2C_PCF_IDLE); |
207 | ||
208 | /* check to see PCF is really idled and we can access status register */ | |
209 | if ((temp = get_pcf(adap, 1)) != (I2C_PCF_PIN | I2C_PCF_BB)) { | |
210 | DEB2(printk(KERN_ERR "i2c-algo-pcf.o: PCF detection failed -- can't select S1` (0x%02x).\n", temp)); | |
211 | return -ENXIO; | |
212 | } | |
0c168ceb | 213 | |
a672b4c1 | 214 | printk(KERN_DEBUG "i2c-algo-pcf.o: detected and initialized PCF8584.\n"); |
1da177e4 LT |
215 | |
216 | return 0; | |
217 | } | |
218 | ||
1da177e4 | 219 | static int pcf_sendbytes(struct i2c_adapter *i2c_adap, const char *buf, |
0c168ceb | 220 | int count, int last) |
1da177e4 LT |
221 | { |
222 | struct i2c_algo_pcf_data *adap = i2c_adap->algo_data; | |
223 | int wrcount, status, timeout; | |
0c168ceb | 224 | |
1da177e4 LT |
225 | for (wrcount=0; wrcount<count; ++wrcount) { |
226 | DEB2(dev_dbg(&i2c_adap->dev, "i2c_write: writing %2.2X\n", | |
0c168ceb | 227 | buf[wrcount] & 0xff)); |
1da177e4 LT |
228 | i2c_outb(adap, buf[wrcount]); |
229 | timeout = wait_for_pin(adap, &status); | |
230 | if (timeout) { | |
0c168ceb RK |
231 | if (timeout == -EINTR) |
232 | return -EINTR; /* arbitration lost */ | |
233 | ||
1da177e4 LT |
234 | i2c_stop(adap); |
235 | dev_err(&i2c_adap->dev, "i2c_write: error - timeout.\n"); | |
236 | return -EREMOTEIO; /* got a better one ?? */ | |
237 | } | |
1da177e4 LT |
238 | if (status & I2C_PCF_LRB) { |
239 | i2c_stop(adap); | |
240 | dev_err(&i2c_adap->dev, "i2c_write: error - no ack.\n"); | |
241 | return -EREMOTEIO; /* got a better one ?? */ | |
242 | } | |
1da177e4 | 243 | } |
0c168ceb | 244 | if (last) |
1da177e4 | 245 | i2c_stop(adap); |
0c168ceb | 246 | else |
1da177e4 | 247 | i2c_repstart(adap); |
1da177e4 | 248 | |
0c168ceb | 249 | return wrcount; |
1da177e4 LT |
250 | } |
251 | ||
1da177e4 | 252 | static int pcf_readbytes(struct i2c_adapter *i2c_adap, char *buf, |
0c168ceb | 253 | int count, int last) |
1da177e4 LT |
254 | { |
255 | int i, status; | |
256 | struct i2c_algo_pcf_data *adap = i2c_adap->algo_data; | |
257 | int wfp; | |
258 | ||
259 | /* increment number of bytes to read by one -- read dummy byte */ | |
260 | for (i = 0; i <= count; i++) { | |
261 | ||
262 | if ((wfp = wait_for_pin(adap, &status))) { | |
0c168ceb RK |
263 | if (wfp == -EINTR) |
264 | return -EINTR; /* arbitration lost */ | |
265 | ||
1da177e4 LT |
266 | i2c_stop(adap); |
267 | dev_err(&i2c_adap->dev, "pcf_readbytes timed out.\n"); | |
0c168ceb | 268 | return -1; |
1da177e4 LT |
269 | } |
270 | ||
1da177e4 LT |
271 | if ((status & I2C_PCF_LRB) && (i != count)) { |
272 | i2c_stop(adap); | |
273 | dev_err(&i2c_adap->dev, "i2c_read: i2c_inb, No ack.\n"); | |
0c168ceb | 274 | return -1; |
1da177e4 | 275 | } |
0c168ceb | 276 | |
1da177e4 LT |
277 | if (i == count - 1) { |
278 | set_pcf(adap, 1, I2C_PCF_ESO); | |
0c168ceb RK |
279 | } else if (i == count) { |
280 | if (last) | |
1da177e4 | 281 | i2c_stop(adap); |
0c168ceb | 282 | else |
1da177e4 | 283 | i2c_repstart(adap); |
0c168ceb | 284 | } |
1da177e4 | 285 | |
0c168ceb | 286 | if (i) |
1da177e4 | 287 | buf[i - 1] = i2c_inb(adap); |
0c168ceb | 288 | else |
1da177e4 | 289 | i2c_inb(adap); /* dummy read */ |
1da177e4 LT |
290 | } |
291 | ||
0c168ceb | 292 | return i - 1; |
1da177e4 LT |
293 | } |
294 | ||
295 | ||
6408a833 JD |
296 | static int pcf_doAddress(struct i2c_algo_pcf_data *adap, |
297 | struct i2c_msg *msg) | |
1da177e4 LT |
298 | { |
299 | unsigned short flags = msg->flags; | |
300 | unsigned char addr; | |
6408a833 JD |
301 | |
302 | addr = msg->addr << 1; | |
303 | if (flags & I2C_M_RD) | |
304 | addr |= 1; | |
305 | if (flags & I2C_M_REV_DIR_ADDR) | |
306 | addr ^= 1; | |
307 | i2c_outb(adap, addr); | |
308 | ||
1da177e4 LT |
309 | return 0; |
310 | } | |
311 | ||
312 | static int pcf_xfer(struct i2c_adapter *i2c_adap, | |
0c168ceb | 313 | struct i2c_msg *msgs, |
1da177e4 LT |
314 | int num) |
315 | { | |
316 | struct i2c_algo_pcf_data *adap = i2c_adap->algo_data; | |
317 | struct i2c_msg *pmsg; | |
318 | int i; | |
319 | int ret=0, timeout, status; | |
0c168ceb | 320 | |
30091404 DM |
321 | if (adap->xfer_begin) |
322 | adap->xfer_begin(adap->data); | |
1da177e4 LT |
323 | |
324 | /* Check for bus busy */ | |
325 | timeout = wait_for_bb(adap); | |
326 | if (timeout) { | |
327 | DEB2(printk(KERN_ERR "i2c-algo-pcf.o: " | |
0c168ceb | 328 | "Timeout waiting for BB in pcf_xfer\n");) |
30091404 DM |
329 | i = -EIO; |
330 | goto out; | |
1da177e4 | 331 | } |
0c168ceb | 332 | |
1da177e4 LT |
333 | for (i = 0;ret >= 0 && i < num; i++) { |
334 | pmsg = &msgs[i]; | |
335 | ||
336 | DEB2(printk(KERN_DEBUG "i2c-algo-pcf.o: Doing %s %d bytes to 0x%02x - %d of %d messages\n", | |
337 | pmsg->flags & I2C_M_RD ? "read" : "write", | |
0c168ceb RK |
338 | pmsg->len, pmsg->addr, i + 1, num);) |
339 | ||
6408a833 | 340 | ret = pcf_doAddress(adap, pmsg); |
1da177e4 LT |
341 | |
342 | /* Send START */ | |
0c168ceb RK |
343 | if (i == 0) |
344 | i2c_start(adap); | |
345 | ||
1da177e4 LT |
346 | /* Wait for PIN (pending interrupt NOT) */ |
347 | timeout = wait_for_pin(adap, &status); | |
348 | if (timeout) { | |
349 | if (timeout == -EINTR) { | |
350 | /* arbitration lost */ | |
30091404 DM |
351 | i = -EINTR; |
352 | goto out; | |
1da177e4 LT |
353 | } |
354 | i2c_stop(adap); | |
355 | DEB2(printk(KERN_ERR "i2c-algo-pcf.o: Timeout waiting " | |
356 | "for PIN(1) in pcf_xfer\n");) | |
30091404 DM |
357 | i = -EREMOTEIO; |
358 | goto out; | |
1da177e4 | 359 | } |
0c168ceb | 360 | |
1da177e4 LT |
361 | /* Check LRB (last rcvd bit - slave ack) */ |
362 | if (status & I2C_PCF_LRB) { | |
363 | i2c_stop(adap); | |
364 | DEB2(printk(KERN_ERR "i2c-algo-pcf.o: No LRB(1) in pcf_xfer\n");) | |
30091404 DM |
365 | i = -EREMOTEIO; |
366 | goto out; | |
1da177e4 | 367 | } |
0c168ceb | 368 | |
1da177e4 LT |
369 | DEB3(printk(KERN_DEBUG "i2c-algo-pcf.o: Msg %d, addr=0x%x, flags=0x%x, len=%d\n", |
370 | i, msgs[i].addr, msgs[i].flags, msgs[i].len);) | |
0c168ceb | 371 | |
1da177e4 | 372 | if (pmsg->flags & I2C_M_RD) { |
1da177e4 | 373 | ret = pcf_readbytes(i2c_adap, pmsg->buf, pmsg->len, |
0c168ceb RK |
374 | (i + 1 == num)); |
375 | ||
1da177e4 LT |
376 | if (ret != pmsg->len) { |
377 | DEB2(printk(KERN_DEBUG "i2c-algo-pcf.o: fail: " | |
378 | "only read %d bytes.\n",ret)); | |
379 | } else { | |
380 | DEB2(printk(KERN_DEBUG "i2c-algo-pcf.o: read %d bytes.\n",ret)); | |
381 | } | |
0c168ceb | 382 | } else { |
1da177e4 | 383 | ret = pcf_sendbytes(i2c_adap, pmsg->buf, pmsg->len, |
0c168ceb RK |
384 | (i + 1 == num)); |
385 | ||
1da177e4 LT |
386 | if (ret != pmsg->len) { |
387 | DEB2(printk(KERN_DEBUG "i2c-algo-pcf.o: fail: " | |
388 | "only wrote %d bytes.\n",ret)); | |
389 | } else { | |
390 | DEB2(printk(KERN_DEBUG "i2c-algo-pcf.o: wrote %d bytes.\n",ret)); | |
391 | } | |
392 | } | |
393 | } | |
394 | ||
30091404 DM |
395 | out: |
396 | if (adap->xfer_end) | |
397 | adap->xfer_end(adap->data); | |
0c168ceb | 398 | return i; |
1da177e4 LT |
399 | } |
400 | ||
401 | static u32 pcf_func(struct i2c_adapter *adap) | |
402 | { | |
0c168ceb | 403 | return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | |
6408a833 | 404 | I2C_FUNC_PROTOCOL_MANGLING; |
1da177e4 LT |
405 | } |
406 | ||
0c168ceb | 407 | /* exported algorithm data: */ |
9e11a9fb | 408 | static const struct i2c_algorithm pcf_algo = { |
1da177e4 LT |
409 | .master_xfer = pcf_xfer, |
410 | .functionality = pcf_func, | |
411 | }; | |
412 | ||
0c168ceb RK |
413 | /* |
414 | * registering functions to load algorithms at runtime | |
1da177e4 LT |
415 | */ |
416 | int i2c_pcf_add_bus(struct i2c_adapter *adap) | |
417 | { | |
418 | struct i2c_algo_pcf_data *pcf_adap = adap->algo_data; | |
419 | int rval; | |
420 | ||
421 | DEB2(dev_dbg(&adap->dev, "hw routines registered.\n")); | |
422 | ||
423 | /* register new adapter to i2c module... */ | |
1da177e4 | 424 | adap->algo = &pcf_algo; |
1da177e4 | 425 | |
b39ad0cf MH |
426 | if ((rval = pcf_init_8584(pcf_adap))) |
427 | return rval; | |
428 | ||
429 | rval = i2c_add_adapter(adap); | |
430 | ||
1da177e4 LT |
431 | return rval; |
432 | } | |
1da177e4 | 433 | EXPORT_SYMBOL(i2c_pcf_add_bus); |
1da177e4 LT |
434 | |
435 | MODULE_AUTHOR("Hans Berglund <hb@spacetec.no>"); | |
436 | MODULE_DESCRIPTION("I2C-Bus PCF8584 algorithm"); | |
437 | MODULE_LICENSE("GPL"); | |
438 | ||
439 | module_param(i2c_debug, int, S_IRUGO | S_IWUSR); | |
440 | MODULE_PARM_DESC(i2c_debug, | |
0c168ceb | 441 | "debug level - 0 off; 1 normal; 2,3 more verbose; 9 pcf-protocol"); |