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Commit | Line | Data |
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1da177e4 | 1 | /* |
a8018766 | 2 | * Copyright (c) 2004 Evgeniy Polyakov <zbr@ioremap.net> |
7785925d | 3 | * |
1da177e4 LT |
4 | * This program is free software; you can redistribute it and/or modify |
5 | * it under the terms of the GNU General Public License as published by | |
6 | * the Free Software Foundation; either version 2 of the License, or | |
7 | * (at your option) any later version. | |
8 | * | |
9 | * This program is distributed in the hope that it will be useful, | |
10 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
12 | * GNU General Public License for more details. | |
1da177e4 LT |
13 | */ |
14 | ||
15 | #include <asm/io.h> | |
16 | ||
17 | #include <linux/delay.h> | |
18 | #include <linux/moduleparam.h> | |
339f0723 | 19 | #include <linux/module.h> |
1da177e4 | 20 | |
de0d6dbd | 21 | #include "w1_internal.h" |
1da177e4 | 22 | |
a9fb1c7b | 23 | static int w1_delay_parm = 1; |
1da177e4 LT |
24 | module_param_named(delay_coef, w1_delay_parm, int, 0); |
25 | ||
8f1e1251 MF |
26 | static int w1_disable_irqs = 0; |
27 | module_param_named(disable_irqs, w1_disable_irqs, int, 0); | |
28 | ||
1da177e4 LT |
29 | static u8 w1_crc8_table[] = { |
30 | 0, 94, 188, 226, 97, 63, 221, 131, 194, 156, 126, 32, 163, 253, 31, 65, | |
31 | 157, 195, 33, 127, 252, 162, 64, 30, 95, 1, 227, 189, 62, 96, 130, 220, | |
32 | 35, 125, 159, 193, 66, 28, 254, 160, 225, 191, 93, 3, 128, 222, 60, 98, | |
33 | 190, 224, 2, 92, 223, 129, 99, 61, 124, 34, 192, 158, 29, 67, 161, 255, | |
34 | 70, 24, 250, 164, 39, 121, 155, 197, 132, 218, 56, 102, 229, 187, 89, 7, | |
35 | 219, 133, 103, 57, 186, 228, 6, 88, 25, 71, 165, 251, 120, 38, 196, 154, | |
36 | 101, 59, 217, 135, 4, 90, 184, 230, 167, 249, 27, 69, 198, 152, 122, 36, | |
37 | 248, 166, 68, 26, 153, 199, 37, 123, 58, 100, 134, 216, 91, 5, 231, 185, | |
38 | 140, 210, 48, 110, 237, 179, 81, 15, 78, 16, 242, 172, 47, 113, 147, 205, | |
39 | 17, 79, 173, 243, 112, 46, 204, 146, 211, 141, 111, 49, 178, 236, 14, 80, | |
40 | 175, 241, 19, 77, 206, 144, 114, 44, 109, 51, 209, 143, 12, 82, 176, 238, | |
41 | 50, 108, 142, 208, 83, 13, 239, 177, 240, 174, 76, 18, 145, 207, 45, 115, | |
42 | 202, 148, 118, 40, 171, 245, 23, 73, 8, 86, 180, 234, 105, 55, 213, 139, | |
43 | 87, 9, 235, 181, 54, 104, 138, 212, 149, 203, 41, 119, 244, 170, 72, 22, | |
44 | 233, 183, 85, 11, 136, 214, 52, 106, 43, 117, 151, 201, 74, 20, 246, 168, | |
45 | 116, 42, 200, 150, 21, 75, 169, 247, 182, 232, 10, 84, 215, 137, 107, 53 | |
46 | }; | |
47 | ||
70d484bf | 48 | static void w1_delay(unsigned long tm) |
1da177e4 LT |
49 | { |
50 | udelay(tm * w1_delay_parm); | |
51 | } | |
52 | ||
be57ce26 EP |
53 | static void w1_write_bit(struct w1_master *dev, int bit); |
54 | static u8 w1_read_bit(struct w1_master *dev); | |
55 | ||
56 | /** | |
b3be177a DF |
57 | * w1_touch_bit() - Generates a write-0 or write-1 cycle and samples the level. |
58 | * @dev: the master device | |
59 | * @bit: 0 - write a 0, 1 - write a 0 read the level | |
be57ce26 | 60 | */ |
eb8470db | 61 | u8 w1_touch_bit(struct w1_master *dev, int bit) |
1da177e4 LT |
62 | { |
63 | if (dev->bus_master->touch_bit) | |
64 | return dev->bus_master->touch_bit(dev->bus_master->data, bit); | |
be57ce26 | 65 | else if (bit) |
1da177e4 | 66 | return w1_read_bit(dev); |
be57ce26 EP |
67 | else { |
68 | w1_write_bit(dev, 0); | |
23c36c1a | 69 | return 0; |
be57ce26 | 70 | } |
1da177e4 | 71 | } |
eb8470db | 72 | EXPORT_SYMBOL_GPL(w1_touch_bit); |
1da177e4 | 73 | |
be57ce26 | 74 | /** |
b3be177a DF |
75 | * w1_write_bit() - Generates a write-0 or write-1 cycle. |
76 | * @dev: the master device | |
77 | * @bit: bit to write | |
78 | * | |
be57ce26 EP |
79 | * Only call if dev->bus_master->touch_bit is NULL |
80 | */ | |
81 | static void w1_write_bit(struct w1_master *dev, int bit) | |
1da177e4 | 82 | { |
8f1e1251 MF |
83 | unsigned long flags = 0; |
84 | ||
85 | if(w1_disable_irqs) local_irq_save(flags); | |
86 | ||
1da177e4 LT |
87 | if (bit) { |
88 | dev->bus_master->write_bit(dev->bus_master->data, 0); | |
89 | w1_delay(6); | |
90 | dev->bus_master->write_bit(dev->bus_master->data, 1); | |
91 | w1_delay(64); | |
92 | } else { | |
93 | dev->bus_master->write_bit(dev->bus_master->data, 0); | |
94 | w1_delay(60); | |
95 | dev->bus_master->write_bit(dev->bus_master->data, 1); | |
96 | w1_delay(10); | |
97 | } | |
8f1e1251 MF |
98 | |
99 | if(w1_disable_irqs) local_irq_restore(flags); | |
1da177e4 LT |
100 | } |
101 | ||
6a158c0d | 102 | /** |
b3be177a DF |
103 | * w1_pre_write() - pre-write operations |
104 | * @dev: the master device | |
105 | * | |
6a158c0d DF |
106 | * Pre-write operation, currently only supporting strong pullups. |
107 | * Program the hardware for a strong pullup, if one has been requested and | |
108 | * the hardware supports it. | |
6a158c0d DF |
109 | */ |
110 | static void w1_pre_write(struct w1_master *dev) | |
111 | { | |
112 | if (dev->pullup_duration && | |
113 | dev->enable_pullup && dev->bus_master->set_pullup) { | |
114 | dev->bus_master->set_pullup(dev->bus_master->data, | |
115 | dev->pullup_duration); | |
116 | } | |
117 | } | |
118 | ||
119 | /** | |
b3be177a DF |
120 | * w1_post_write() - post-write options |
121 | * @dev: the master device | |
122 | * | |
6a158c0d DF |
123 | * Post-write operation, currently only supporting strong pullups. |
124 | * If a strong pullup was requested, clear it if the hardware supports | |
125 | * them, or execute the delay otherwise, in either case clear the request. | |
6a158c0d DF |
126 | */ |
127 | static void w1_post_write(struct w1_master *dev) | |
128 | { | |
129 | if (dev->pullup_duration) { | |
130 | if (dev->enable_pullup && dev->bus_master->set_pullup) | |
131 | dev->bus_master->set_pullup(dev->bus_master->data, 0); | |
132 | else | |
133 | msleep(dev->pullup_duration); | |
134 | dev->pullup_duration = 0; | |
135 | } | |
136 | } | |
137 | ||
be57ce26 | 138 | /** |
b3be177a DF |
139 | * w1_write_8() - Writes 8 bits. |
140 | * @dev: the master device | |
141 | * @byte: the byte to write | |
be57ce26 | 142 | */ |
1da177e4 LT |
143 | void w1_write_8(struct w1_master *dev, u8 byte) |
144 | { | |
145 | int i; | |
146 | ||
6a158c0d DF |
147 | if (dev->bus_master->write_byte) { |
148 | w1_pre_write(dev); | |
1da177e4 | 149 | dev->bus_master->write_byte(dev->bus_master->data, byte); |
6a158c0d | 150 | } |
1da177e4 | 151 | else |
6a158c0d DF |
152 | for (i = 0; i < 8; ++i) { |
153 | if (i == 7) | |
154 | w1_pre_write(dev); | |
be57ce26 | 155 | w1_touch_bit(dev, (byte >> i) & 0x1); |
6a158c0d DF |
156 | } |
157 | w1_post_write(dev); | |
1da177e4 | 158 | } |
339f0723 | 159 | EXPORT_SYMBOL_GPL(w1_write_8); |
1da177e4 | 160 | |
be57ce26 EP |
161 | |
162 | /** | |
b3be177a DF |
163 | * w1_read_bit() - Generates a write-1 cycle and samples the level. |
164 | * @dev: the master device | |
165 | * | |
be57ce26 EP |
166 | * Only call if dev->bus_master->touch_bit is NULL |
167 | */ | |
168 | static u8 w1_read_bit(struct w1_master *dev) | |
1da177e4 LT |
169 | { |
170 | int result; | |
8f1e1251 | 171 | unsigned long flags = 0; |
1da177e4 | 172 | |
3fd306c8 JW |
173 | /* sample timing is critical here */ |
174 | local_irq_save(flags); | |
1da177e4 LT |
175 | dev->bus_master->write_bit(dev->bus_master->data, 0); |
176 | w1_delay(6); | |
177 | dev->bus_master->write_bit(dev->bus_master->data, 1); | |
178 | w1_delay(9); | |
179 | ||
180 | result = dev->bus_master->read_bit(dev->bus_master->data); | |
3fd306c8 JW |
181 | local_irq_restore(flags); |
182 | ||
1da177e4 LT |
183 | w1_delay(55); |
184 | ||
185 | return result & 0x1; | |
186 | } | |
187 | ||
6b729861 | 188 | /** |
b3be177a DF |
189 | * w1_triplet() - * Does a triplet - used for searching ROM addresses. |
190 | * @dev: the master device | |
191 | * @bdir: the bit to write if both id_bit and comp_bit are 0 | |
192 | * | |
6b729861 EP |
193 | * Return bits: |
194 | * bit 0 = id_bit | |
195 | * bit 1 = comp_bit | |
196 | * bit 2 = dir_taken | |
197 | * If both bits 0 & 1 are set, the search should be restarted. | |
198 | * | |
b3be177a | 199 | * Return: bit fields - see above |
6b729861 EP |
200 | */ |
201 | u8 w1_triplet(struct w1_master *dev, int bdir) | |
202 | { | |
23c36c1a DM |
203 | if (dev->bus_master->triplet) |
204 | return dev->bus_master->triplet(dev->bus_master->data, bdir); | |
6b729861 EP |
205 | else { |
206 | u8 id_bit = w1_touch_bit(dev, 1); | |
207 | u8 comp_bit = w1_touch_bit(dev, 1); | |
208 | u8 retval; | |
209 | ||
23c36c1a DM |
210 | if (id_bit && comp_bit) |
211 | return 0x03; /* error */ | |
6b729861 | 212 | |
23c36c1a | 213 | if (!id_bit && !comp_bit) { |
6b729861 EP |
214 | /* Both bits are valid, take the direction given */ |
215 | retval = bdir ? 0x04 : 0; | |
216 | } else { | |
217 | /* Only one bit is valid, take that direction */ | |
218 | bdir = id_bit; | |
219 | retval = id_bit ? 0x05 : 0x02; | |
220 | } | |
221 | ||
23c36c1a | 222 | if (dev->bus_master->touch_bit) |
6b729861 EP |
223 | w1_touch_bit(dev, bdir); |
224 | else | |
225 | w1_write_bit(dev, bdir); | |
23c36c1a | 226 | return retval; |
6b729861 EP |
227 | } |
228 | } | |
dd6478d6 | 229 | EXPORT_SYMBOL_GPL(w1_triplet); |
6b729861 | 230 | |
be57ce26 | 231 | /** |
b3be177a DF |
232 | * w1_read_8() - Reads 8 bits. |
233 | * @dev: the master device | |
be57ce26 | 234 | * |
b3be177a | 235 | * Return: the byte read |
be57ce26 | 236 | */ |
34e453d4 | 237 | u8 w1_read_8(struct w1_master *dev) |
1da177e4 LT |
238 | { |
239 | int i; | |
240 | u8 res = 0; | |
241 | ||
242 | if (dev->bus_master->read_byte) | |
243 | res = dev->bus_master->read_byte(dev->bus_master->data); | |
244 | else | |
245 | for (i = 0; i < 8; ++i) | |
be57ce26 | 246 | res |= (w1_touch_bit(dev,1) << i); |
1da177e4 LT |
247 | |
248 | return res; | |
249 | } | |
34e453d4 | 250 | EXPORT_SYMBOL_GPL(w1_read_8); |
1da177e4 | 251 | |
be57ce26 | 252 | /** |
b3be177a DF |
253 | * w1_write_block() - Writes a series of bytes. |
254 | * @dev: the master device | |
255 | * @buf: pointer to the data to write | |
256 | * @len: the number of bytes to write | |
be57ce26 EP |
257 | */ |
258 | void w1_write_block(struct w1_master *dev, const u8 *buf, int len) | |
1da177e4 LT |
259 | { |
260 | int i; | |
261 | ||
6a158c0d DF |
262 | if (dev->bus_master->write_block) { |
263 | w1_pre_write(dev); | |
1da177e4 | 264 | dev->bus_master->write_block(dev->bus_master->data, buf, len); |
6a158c0d | 265 | } |
1da177e4 LT |
266 | else |
267 | for (i = 0; i < len; ++i) | |
6a158c0d DF |
268 | w1_write_8(dev, buf[i]); /* calls w1_pre_write */ |
269 | w1_post_write(dev); | |
1da177e4 | 270 | } |
339f0723 | 271 | EXPORT_SYMBOL_GPL(w1_write_block); |
1da177e4 | 272 | |
9be62e0b | 273 | /** |
b3be177a DF |
274 | * w1_touch_block() - Touches a series of bytes. |
275 | * @dev: the master device | |
276 | * @buf: pointer to the data to write | |
277 | * @len: the number of bytes to write | |
9be62e0b EP |
278 | */ |
279 | void w1_touch_block(struct w1_master *dev, u8 *buf, int len) | |
280 | { | |
281 | int i, j; | |
282 | u8 tmp; | |
283 | ||
284 | for (i = 0; i < len; ++i) { | |
285 | tmp = 0; | |
286 | for (j = 0; j < 8; ++j) { | |
287 | if (j == 7) | |
288 | w1_pre_write(dev); | |
289 | tmp |= w1_touch_bit(dev, (buf[i] >> j) & 0x1) << j; | |
290 | } | |
291 | ||
292 | buf[i] = tmp; | |
293 | } | |
294 | } | |
295 | EXPORT_SYMBOL_GPL(w1_touch_block); | |
296 | ||
be57ce26 | 297 | /** |
b3be177a DF |
298 | * w1_read_block() - Reads a series of bytes. |
299 | * @dev: the master device | |
300 | * @buf: pointer to the buffer to fill | |
301 | * @len: the number of bytes to read | |
302 | * Return: the number of bytes read | |
be57ce26 | 303 | */ |
1da177e4 LT |
304 | u8 w1_read_block(struct w1_master *dev, u8 *buf, int len) |
305 | { | |
306 | int i; | |
307 | u8 ret; | |
308 | ||
309 | if (dev->bus_master->read_block) | |
310 | ret = dev->bus_master->read_block(dev->bus_master->data, buf, len); | |
311 | else { | |
312 | for (i = 0; i < len; ++i) | |
313 | buf[i] = w1_read_8(dev); | |
314 | ret = len; | |
315 | } | |
316 | ||
317 | return ret; | |
318 | } | |
339f0723 | 319 | EXPORT_SYMBOL_GPL(w1_read_block); |
1da177e4 | 320 | |
be57ce26 | 321 | /** |
b3be177a DF |
322 | * w1_reset_bus() - Issues a reset bus sequence. |
323 | * @dev: the master device | |
324 | * Return: 0=Device present, 1=No device present or error | |
be57ce26 | 325 | */ |
1da177e4 LT |
326 | int w1_reset_bus(struct w1_master *dev) |
327 | { | |
be57ce26 | 328 | int result; |
8f1e1251 MF |
329 | unsigned long flags = 0; |
330 | ||
331 | if(w1_disable_irqs) local_irq_save(flags); | |
1da177e4 LT |
332 | |
333 | if (dev->bus_master->reset_bus) | |
334 | result = dev->bus_master->reset_bus(dev->bus_master->data) & 0x1; | |
335 | else { | |
336 | dev->bus_master->write_bit(dev->bus_master->data, 0); | |
8e3dae2b DF |
337 | /* minimum 480, max ? us |
338 | * be nice and sleep, except 18b20 spec lists 960us maximum, | |
339 | * so until we can sleep with microsecond accuracy, spin. | |
340 | * Feel free to come up with some other way to give up the | |
341 | * cpu for such a short amount of time AND get it back in | |
342 | * the maximum amount of time. | |
343 | */ | |
8f1e1251 | 344 | w1_delay(500); |
1da177e4 LT |
345 | dev->bus_master->write_bit(dev->bus_master->data, 1); |
346 | w1_delay(70); | |
347 | ||
348 | result = dev->bus_master->read_bit(dev->bus_master->data) & 0x1; | |
0db71fec | 349 | /* minimum 70 (above) + 430 = 500 us |
8e3dae2b DF |
350 | * There aren't any timing requirements between a reset and |
351 | * the following transactions. Sleeping is safe here. | |
352 | */ | |
8f1e1251 | 353 | /* w1_delay(430); min required time */ |
8e3dae2b | 354 | msleep(1); |
1da177e4 LT |
355 | } |
356 | ||
8f1e1251 MF |
357 | if(w1_disable_irqs) local_irq_restore(flags); |
358 | ||
1da177e4 LT |
359 | return result; |
360 | } | |
339f0723 | 361 | EXPORT_SYMBOL_GPL(w1_reset_bus); |
1da177e4 LT |
362 | |
363 | u8 w1_calc_crc8(u8 * data, int len) | |
364 | { | |
365 | u8 crc = 0; | |
366 | ||
367 | while (len--) | |
368 | crc = w1_crc8_table[crc ^ *data++]; | |
369 | ||
370 | return crc; | |
371 | } | |
339f0723 | 372 | EXPORT_SYMBOL_GPL(w1_calc_crc8); |
1da177e4 | 373 | |
12003375 | 374 | void w1_search_devices(struct w1_master *dev, u8 search_type, w1_slave_found_callback cb) |
1da177e4 LT |
375 | { |
376 | dev->attempts++; | |
377 | if (dev->bus_master->search) | |
c30c9b15 DF |
378 | dev->bus_master->search(dev->bus_master->data, dev, |
379 | search_type, cb); | |
1da177e4 | 380 | else |
12003375 | 381 | w1_search(dev, search_type, cb); |
1da177e4 LT |
382 | } |
383 | ||
ea7d8f65 | 384 | /** |
b3be177a DF |
385 | * w1_reset_select_slave() - reset and select a slave |
386 | * @sl: the slave to select | |
387 | * | |
ea7d8f65 | 388 | * Resets the bus and then selects the slave by sending either a skip rom |
b3be177a DF |
389 | * or a rom match. A skip rom is issued if there is only one device |
390 | * registered on the bus. | |
ea7d8f65 EP |
391 | * The w1 master lock must be held. |
392 | * | |
b3be177a | 393 | * Return: 0=success, anything else=error |
ea7d8f65 EP |
394 | */ |
395 | int w1_reset_select_slave(struct w1_slave *sl) | |
396 | { | |
397 | if (w1_reset_bus(sl->master)) | |
398 | return -1; | |
399 | ||
400 | if (sl->master->slave_count == 1) | |
401 | w1_write_8(sl->master, W1_SKIP_ROM); | |
402 | else { | |
403 | u8 match[9] = {W1_MATCH_ROM, }; | |
f00a1892 EP |
404 | u64 rn = le64_to_cpu(*((u64*)&sl->reg_num)); |
405 | ||
406 | memcpy(&match[1], &rn, 8); | |
ea7d8f65 EP |
407 | w1_write_block(sl->master, match, 9); |
408 | } | |
409 | return 0; | |
410 | } | |
339f0723 | 411 | EXPORT_SYMBOL_GPL(w1_reset_select_slave); |
6a158c0d | 412 | |
67dfd54c | 413 | /** |
b3be177a DF |
414 | * w1_reset_resume_command() - resume instead of another match ROM |
415 | * @dev: the master device | |
416 | * | |
67dfd54c JFD |
417 | * When the workflow with a slave amongst many requires several |
418 | * successive commands a reset between each, this function is similar | |
419 | * to doing a reset then a match ROM for the last matched ROM. The | |
420 | * advantage being that the matched ROM step is skipped in favor of the | |
421 | * resume command. The slave must support the command of course. | |
422 | * | |
423 | * If the bus has only one slave, traditionnaly the match ROM is skipped | |
424 | * and a "SKIP ROM" is done for efficiency. On multi-slave busses, this | |
425 | * doesn't work of course, but the resume command is the next best thing. | |
426 | * | |
427 | * The w1 master lock must be held. | |
67dfd54c JFD |
428 | */ |
429 | int w1_reset_resume_command(struct w1_master *dev) | |
430 | { | |
431 | if (w1_reset_bus(dev)) | |
432 | return -1; | |
433 | ||
434 | /* This will make only the last matched slave perform a skip ROM. */ | |
435 | w1_write_8(dev, W1_RESUME_CMD); | |
436 | return 0; | |
437 | } | |
438 | EXPORT_SYMBOL_GPL(w1_reset_resume_command); | |
439 | ||
6a158c0d | 440 | /** |
b3be177a DF |
441 | * w1_next_pullup() - register for a strong pullup |
442 | * @dev: the master device | |
443 | * @delay: time in milliseconds | |
444 | * | |
6a158c0d DF |
445 | * Put out a strong pull-up of the specified duration after the next write |
446 | * operation. Not all hardware supports strong pullups. Hardware that | |
447 | * doesn't support strong pullups will sleep for the given time after the | |
448 | * write operation without a strong pullup. This is a one shot request for | |
449 | * the next write, specifying zero will clear a previous request. | |
450 | * The w1 master lock must be held. | |
451 | * | |
b3be177a | 452 | * Return: 0=success, anything else=error |
6a158c0d DF |
453 | */ |
454 | void w1_next_pullup(struct w1_master *dev, int delay) | |
455 | { | |
456 | dev->pullup_duration = delay; | |
457 | } | |
458 | EXPORT_SYMBOL_GPL(w1_next_pullup); |