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Commit | Line | Data |
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c942fddf | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
1da177e4 | 2 | /* |
a8018766 | 3 | * Copyright (c) 2004 Evgeniy Polyakov <zbr@ioremap.net> |
1da177e4 LT |
4 | */ |
5 | ||
6 | #include <asm/io.h> | |
7 | ||
8 | #include <linux/delay.h> | |
9 | #include <linux/moduleparam.h> | |
339f0723 | 10 | #include <linux/module.h> |
1da177e4 | 11 | |
de0d6dbd | 12 | #include "w1_internal.h" |
1da177e4 | 13 | |
a9fb1c7b | 14 | static int w1_delay_parm = 1; |
1da177e4 LT |
15 | module_param_named(delay_coef, w1_delay_parm, int, 0); |
16 | ||
8f1e1251 MF |
17 | static int w1_disable_irqs = 0; |
18 | module_param_named(disable_irqs, w1_disable_irqs, int, 0); | |
19 | ||
1da177e4 LT |
20 | static u8 w1_crc8_table[] = { |
21 | 0, 94, 188, 226, 97, 63, 221, 131, 194, 156, 126, 32, 163, 253, 31, 65, | |
22 | 157, 195, 33, 127, 252, 162, 64, 30, 95, 1, 227, 189, 62, 96, 130, 220, | |
23 | 35, 125, 159, 193, 66, 28, 254, 160, 225, 191, 93, 3, 128, 222, 60, 98, | |
24 | 190, 224, 2, 92, 223, 129, 99, 61, 124, 34, 192, 158, 29, 67, 161, 255, | |
25 | 70, 24, 250, 164, 39, 121, 155, 197, 132, 218, 56, 102, 229, 187, 89, 7, | |
26 | 219, 133, 103, 57, 186, 228, 6, 88, 25, 71, 165, 251, 120, 38, 196, 154, | |
27 | 101, 59, 217, 135, 4, 90, 184, 230, 167, 249, 27, 69, 198, 152, 122, 36, | |
28 | 248, 166, 68, 26, 153, 199, 37, 123, 58, 100, 134, 216, 91, 5, 231, 185, | |
29 | 140, 210, 48, 110, 237, 179, 81, 15, 78, 16, 242, 172, 47, 113, 147, 205, | |
30 | 17, 79, 173, 243, 112, 46, 204, 146, 211, 141, 111, 49, 178, 236, 14, 80, | |
31 | 175, 241, 19, 77, 206, 144, 114, 44, 109, 51, 209, 143, 12, 82, 176, 238, | |
32 | 50, 108, 142, 208, 83, 13, 239, 177, 240, 174, 76, 18, 145, 207, 45, 115, | |
33 | 202, 148, 118, 40, 171, 245, 23, 73, 8, 86, 180, 234, 105, 55, 213, 139, | |
34 | 87, 9, 235, 181, 54, 104, 138, 212, 149, 203, 41, 119, 244, 170, 72, 22, | |
35 | 233, 183, 85, 11, 136, 214, 52, 106, 43, 117, 151, 201, 74, 20, 246, 168, | |
36 | 116, 42, 200, 150, 21, 75, 169, 247, 182, 232, 10, 84, 215, 137, 107, 53 | |
37 | }; | |
38 | ||
70d484bf | 39 | static void w1_delay(unsigned long tm) |
1da177e4 LT |
40 | { |
41 | udelay(tm * w1_delay_parm); | |
42 | } | |
43 | ||
be57ce26 EP |
44 | static void w1_write_bit(struct w1_master *dev, int bit); |
45 | static u8 w1_read_bit(struct w1_master *dev); | |
46 | ||
47 | /** | |
b3be177a DF |
48 | * w1_touch_bit() - Generates a write-0 or write-1 cycle and samples the level. |
49 | * @dev: the master device | |
50 | * @bit: 0 - write a 0, 1 - write a 0 read the level | |
be57ce26 | 51 | */ |
eb8470db | 52 | u8 w1_touch_bit(struct w1_master *dev, int bit) |
1da177e4 LT |
53 | { |
54 | if (dev->bus_master->touch_bit) | |
55 | return dev->bus_master->touch_bit(dev->bus_master->data, bit); | |
be57ce26 | 56 | else if (bit) |
1da177e4 | 57 | return w1_read_bit(dev); |
be57ce26 EP |
58 | else { |
59 | w1_write_bit(dev, 0); | |
23c36c1a | 60 | return 0; |
be57ce26 | 61 | } |
1da177e4 | 62 | } |
eb8470db | 63 | EXPORT_SYMBOL_GPL(w1_touch_bit); |
1da177e4 | 64 | |
be57ce26 | 65 | /** |
b3be177a DF |
66 | * w1_write_bit() - Generates a write-0 or write-1 cycle. |
67 | * @dev: the master device | |
68 | * @bit: bit to write | |
69 | * | |
be57ce26 EP |
70 | * Only call if dev->bus_master->touch_bit is NULL |
71 | */ | |
72 | static void w1_write_bit(struct w1_master *dev, int bit) | |
1da177e4 | 73 | { |
8f1e1251 MF |
74 | unsigned long flags = 0; |
75 | ||
76 | if(w1_disable_irqs) local_irq_save(flags); | |
77 | ||
1da177e4 LT |
78 | if (bit) { |
79 | dev->bus_master->write_bit(dev->bus_master->data, 0); | |
80 | w1_delay(6); | |
81 | dev->bus_master->write_bit(dev->bus_master->data, 1); | |
82 | w1_delay(64); | |
83 | } else { | |
84 | dev->bus_master->write_bit(dev->bus_master->data, 0); | |
85 | w1_delay(60); | |
86 | dev->bus_master->write_bit(dev->bus_master->data, 1); | |
87 | w1_delay(10); | |
88 | } | |
8f1e1251 MF |
89 | |
90 | if(w1_disable_irqs) local_irq_restore(flags); | |
1da177e4 LT |
91 | } |
92 | ||
6a158c0d | 93 | /** |
b3be177a DF |
94 | * w1_pre_write() - pre-write operations |
95 | * @dev: the master device | |
96 | * | |
6a158c0d DF |
97 | * Pre-write operation, currently only supporting strong pullups. |
98 | * Program the hardware for a strong pullup, if one has been requested and | |
99 | * the hardware supports it. | |
6a158c0d DF |
100 | */ |
101 | static void w1_pre_write(struct w1_master *dev) | |
102 | { | |
103 | if (dev->pullup_duration && | |
104 | dev->enable_pullup && dev->bus_master->set_pullup) { | |
105 | dev->bus_master->set_pullup(dev->bus_master->data, | |
106 | dev->pullup_duration); | |
107 | } | |
108 | } | |
109 | ||
110 | /** | |
b3be177a DF |
111 | * w1_post_write() - post-write options |
112 | * @dev: the master device | |
113 | * | |
6a158c0d DF |
114 | * Post-write operation, currently only supporting strong pullups. |
115 | * If a strong pullup was requested, clear it if the hardware supports | |
116 | * them, or execute the delay otherwise, in either case clear the request. | |
6a158c0d DF |
117 | */ |
118 | static void w1_post_write(struct w1_master *dev) | |
119 | { | |
120 | if (dev->pullup_duration) { | |
121 | if (dev->enable_pullup && dev->bus_master->set_pullup) | |
122 | dev->bus_master->set_pullup(dev->bus_master->data, 0); | |
123 | else | |
124 | msleep(dev->pullup_duration); | |
125 | dev->pullup_duration = 0; | |
126 | } | |
127 | } | |
128 | ||
be57ce26 | 129 | /** |
b3be177a DF |
130 | * w1_write_8() - Writes 8 bits. |
131 | * @dev: the master device | |
132 | * @byte: the byte to write | |
be57ce26 | 133 | */ |
1da177e4 LT |
134 | void w1_write_8(struct w1_master *dev, u8 byte) |
135 | { | |
136 | int i; | |
137 | ||
6a158c0d DF |
138 | if (dev->bus_master->write_byte) { |
139 | w1_pre_write(dev); | |
1da177e4 | 140 | dev->bus_master->write_byte(dev->bus_master->data, byte); |
6a158c0d | 141 | } |
1da177e4 | 142 | else |
6a158c0d DF |
143 | for (i = 0; i < 8; ++i) { |
144 | if (i == 7) | |
145 | w1_pre_write(dev); | |
be57ce26 | 146 | w1_touch_bit(dev, (byte >> i) & 0x1); |
6a158c0d DF |
147 | } |
148 | w1_post_write(dev); | |
1da177e4 | 149 | } |
339f0723 | 150 | EXPORT_SYMBOL_GPL(w1_write_8); |
1da177e4 | 151 | |
be57ce26 EP |
152 | |
153 | /** | |
b3be177a DF |
154 | * w1_read_bit() - Generates a write-1 cycle and samples the level. |
155 | * @dev: the master device | |
156 | * | |
be57ce26 EP |
157 | * Only call if dev->bus_master->touch_bit is NULL |
158 | */ | |
159 | static u8 w1_read_bit(struct w1_master *dev) | |
1da177e4 LT |
160 | { |
161 | int result; | |
8f1e1251 | 162 | unsigned long flags = 0; |
1da177e4 | 163 | |
3fd306c8 JW |
164 | /* sample timing is critical here */ |
165 | local_irq_save(flags); | |
1da177e4 LT |
166 | dev->bus_master->write_bit(dev->bus_master->data, 0); |
167 | w1_delay(6); | |
168 | dev->bus_master->write_bit(dev->bus_master->data, 1); | |
169 | w1_delay(9); | |
170 | ||
171 | result = dev->bus_master->read_bit(dev->bus_master->data); | |
3fd306c8 JW |
172 | local_irq_restore(flags); |
173 | ||
1da177e4 LT |
174 | w1_delay(55); |
175 | ||
176 | return result & 0x1; | |
177 | } | |
178 | ||
6b729861 | 179 | /** |
b3be177a DF |
180 | * w1_triplet() - * Does a triplet - used for searching ROM addresses. |
181 | * @dev: the master device | |
182 | * @bdir: the bit to write if both id_bit and comp_bit are 0 | |
183 | * | |
6b729861 EP |
184 | * Return bits: |
185 | * bit 0 = id_bit | |
186 | * bit 1 = comp_bit | |
187 | * bit 2 = dir_taken | |
9167b942 | 188 | * |
6b729861 EP |
189 | * If both bits 0 & 1 are set, the search should be restarted. |
190 | * | |
b3be177a | 191 | * Return: bit fields - see above |
6b729861 EP |
192 | */ |
193 | u8 w1_triplet(struct w1_master *dev, int bdir) | |
194 | { | |
23c36c1a DM |
195 | if (dev->bus_master->triplet) |
196 | return dev->bus_master->triplet(dev->bus_master->data, bdir); | |
6b729861 EP |
197 | else { |
198 | u8 id_bit = w1_touch_bit(dev, 1); | |
199 | u8 comp_bit = w1_touch_bit(dev, 1); | |
200 | u8 retval; | |
201 | ||
23c36c1a DM |
202 | if (id_bit && comp_bit) |
203 | return 0x03; /* error */ | |
6b729861 | 204 | |
23c36c1a | 205 | if (!id_bit && !comp_bit) { |
6b729861 EP |
206 | /* Both bits are valid, take the direction given */ |
207 | retval = bdir ? 0x04 : 0; | |
208 | } else { | |
209 | /* Only one bit is valid, take that direction */ | |
210 | bdir = id_bit; | |
211 | retval = id_bit ? 0x05 : 0x02; | |
212 | } | |
213 | ||
23c36c1a | 214 | if (dev->bus_master->touch_bit) |
6b729861 EP |
215 | w1_touch_bit(dev, bdir); |
216 | else | |
217 | w1_write_bit(dev, bdir); | |
23c36c1a | 218 | return retval; |
6b729861 EP |
219 | } |
220 | } | |
dd6478d6 | 221 | EXPORT_SYMBOL_GPL(w1_triplet); |
6b729861 | 222 | |
be57ce26 | 223 | /** |
b3be177a DF |
224 | * w1_read_8() - Reads 8 bits. |
225 | * @dev: the master device | |
be57ce26 | 226 | * |
b3be177a | 227 | * Return: the byte read |
be57ce26 | 228 | */ |
34e453d4 | 229 | u8 w1_read_8(struct w1_master *dev) |
1da177e4 LT |
230 | { |
231 | int i; | |
232 | u8 res = 0; | |
233 | ||
234 | if (dev->bus_master->read_byte) | |
235 | res = dev->bus_master->read_byte(dev->bus_master->data); | |
236 | else | |
237 | for (i = 0; i < 8; ++i) | |
be57ce26 | 238 | res |= (w1_touch_bit(dev,1) << i); |
1da177e4 LT |
239 | |
240 | return res; | |
241 | } | |
34e453d4 | 242 | EXPORT_SYMBOL_GPL(w1_read_8); |
1da177e4 | 243 | |
be57ce26 | 244 | /** |
b3be177a DF |
245 | * w1_write_block() - Writes a series of bytes. |
246 | * @dev: the master device | |
247 | * @buf: pointer to the data to write | |
248 | * @len: the number of bytes to write | |
be57ce26 EP |
249 | */ |
250 | void w1_write_block(struct w1_master *dev, const u8 *buf, int len) | |
1da177e4 LT |
251 | { |
252 | int i; | |
253 | ||
6a158c0d DF |
254 | if (dev->bus_master->write_block) { |
255 | w1_pre_write(dev); | |
1da177e4 | 256 | dev->bus_master->write_block(dev->bus_master->data, buf, len); |
6a158c0d | 257 | } |
1da177e4 LT |
258 | else |
259 | for (i = 0; i < len; ++i) | |
6a158c0d DF |
260 | w1_write_8(dev, buf[i]); /* calls w1_pre_write */ |
261 | w1_post_write(dev); | |
1da177e4 | 262 | } |
339f0723 | 263 | EXPORT_SYMBOL_GPL(w1_write_block); |
1da177e4 | 264 | |
9be62e0b | 265 | /** |
b3be177a DF |
266 | * w1_touch_block() - Touches a series of bytes. |
267 | * @dev: the master device | |
268 | * @buf: pointer to the data to write | |
269 | * @len: the number of bytes to write | |
9be62e0b EP |
270 | */ |
271 | void w1_touch_block(struct w1_master *dev, u8 *buf, int len) | |
272 | { | |
273 | int i, j; | |
274 | u8 tmp; | |
275 | ||
276 | for (i = 0; i < len; ++i) { | |
277 | tmp = 0; | |
278 | for (j = 0; j < 8; ++j) { | |
279 | if (j == 7) | |
280 | w1_pre_write(dev); | |
281 | tmp |= w1_touch_bit(dev, (buf[i] >> j) & 0x1) << j; | |
282 | } | |
283 | ||
284 | buf[i] = tmp; | |
285 | } | |
286 | } | |
287 | EXPORT_SYMBOL_GPL(w1_touch_block); | |
288 | ||
be57ce26 | 289 | /** |
b3be177a DF |
290 | * w1_read_block() - Reads a series of bytes. |
291 | * @dev: the master device | |
292 | * @buf: pointer to the buffer to fill | |
293 | * @len: the number of bytes to read | |
294 | * Return: the number of bytes read | |
be57ce26 | 295 | */ |
1da177e4 LT |
296 | u8 w1_read_block(struct w1_master *dev, u8 *buf, int len) |
297 | { | |
298 | int i; | |
299 | u8 ret; | |
300 | ||
301 | if (dev->bus_master->read_block) | |
302 | ret = dev->bus_master->read_block(dev->bus_master->data, buf, len); | |
303 | else { | |
304 | for (i = 0; i < len; ++i) | |
305 | buf[i] = w1_read_8(dev); | |
306 | ret = len; | |
307 | } | |
308 | ||
309 | return ret; | |
310 | } | |
339f0723 | 311 | EXPORT_SYMBOL_GPL(w1_read_block); |
1da177e4 | 312 | |
be57ce26 | 313 | /** |
b3be177a DF |
314 | * w1_reset_bus() - Issues a reset bus sequence. |
315 | * @dev: the master device | |
316 | * Return: 0=Device present, 1=No device present or error | |
be57ce26 | 317 | */ |
1da177e4 LT |
318 | int w1_reset_bus(struct w1_master *dev) |
319 | { | |
be57ce26 | 320 | int result; |
8f1e1251 MF |
321 | unsigned long flags = 0; |
322 | ||
323 | if(w1_disable_irqs) local_irq_save(flags); | |
1da177e4 LT |
324 | |
325 | if (dev->bus_master->reset_bus) | |
326 | result = dev->bus_master->reset_bus(dev->bus_master->data) & 0x1; | |
327 | else { | |
328 | dev->bus_master->write_bit(dev->bus_master->data, 0); | |
8e3dae2b DF |
329 | /* minimum 480, max ? us |
330 | * be nice and sleep, except 18b20 spec lists 960us maximum, | |
331 | * so until we can sleep with microsecond accuracy, spin. | |
332 | * Feel free to come up with some other way to give up the | |
333 | * cpu for such a short amount of time AND get it back in | |
334 | * the maximum amount of time. | |
335 | */ | |
8f1e1251 | 336 | w1_delay(500); |
1da177e4 LT |
337 | dev->bus_master->write_bit(dev->bus_master->data, 1); |
338 | w1_delay(70); | |
339 | ||
340 | result = dev->bus_master->read_bit(dev->bus_master->data) & 0x1; | |
0db71fec | 341 | /* minimum 70 (above) + 430 = 500 us |
8e3dae2b DF |
342 | * There aren't any timing requirements between a reset and |
343 | * the following transactions. Sleeping is safe here. | |
344 | */ | |
8f1e1251 | 345 | /* w1_delay(430); min required time */ |
8e3dae2b | 346 | msleep(1); |
1da177e4 LT |
347 | } |
348 | ||
8f1e1251 MF |
349 | if(w1_disable_irqs) local_irq_restore(flags); |
350 | ||
1da177e4 LT |
351 | return result; |
352 | } | |
339f0723 | 353 | EXPORT_SYMBOL_GPL(w1_reset_bus); |
1da177e4 LT |
354 | |
355 | u8 w1_calc_crc8(u8 * data, int len) | |
356 | { | |
357 | u8 crc = 0; | |
358 | ||
359 | while (len--) | |
360 | crc = w1_crc8_table[crc ^ *data++]; | |
361 | ||
362 | return crc; | |
363 | } | |
339f0723 | 364 | EXPORT_SYMBOL_GPL(w1_calc_crc8); |
1da177e4 | 365 | |
12003375 | 366 | void w1_search_devices(struct w1_master *dev, u8 search_type, w1_slave_found_callback cb) |
1da177e4 LT |
367 | { |
368 | dev->attempts++; | |
369 | if (dev->bus_master->search) | |
c30c9b15 DF |
370 | dev->bus_master->search(dev->bus_master->data, dev, |
371 | search_type, cb); | |
1da177e4 | 372 | else |
12003375 | 373 | w1_search(dev, search_type, cb); |
1da177e4 LT |
374 | } |
375 | ||
ea7d8f65 | 376 | /** |
b3be177a DF |
377 | * w1_reset_select_slave() - reset and select a slave |
378 | * @sl: the slave to select | |
379 | * | |
ea7d8f65 | 380 | * Resets the bus and then selects the slave by sending either a skip rom |
b3be177a DF |
381 | * or a rom match. A skip rom is issued if there is only one device |
382 | * registered on the bus. | |
ea7d8f65 EP |
383 | * The w1 master lock must be held. |
384 | * | |
b3be177a | 385 | * Return: 0=success, anything else=error |
ea7d8f65 EP |
386 | */ |
387 | int w1_reset_select_slave(struct w1_slave *sl) | |
388 | { | |
389 | if (w1_reset_bus(sl->master)) | |
390 | return -1; | |
391 | ||
392 | if (sl->master->slave_count == 1) | |
393 | w1_write_8(sl->master, W1_SKIP_ROM); | |
394 | else { | |
395 | u8 match[9] = {W1_MATCH_ROM, }; | |
f00a1892 EP |
396 | u64 rn = le64_to_cpu(*((u64*)&sl->reg_num)); |
397 | ||
398 | memcpy(&match[1], &rn, 8); | |
ea7d8f65 EP |
399 | w1_write_block(sl->master, match, 9); |
400 | } | |
401 | return 0; | |
402 | } | |
339f0723 | 403 | EXPORT_SYMBOL_GPL(w1_reset_select_slave); |
6a158c0d | 404 | |
67dfd54c | 405 | /** |
b3be177a DF |
406 | * w1_reset_resume_command() - resume instead of another match ROM |
407 | * @dev: the master device | |
408 | * | |
67dfd54c JFD |
409 | * When the workflow with a slave amongst many requires several |
410 | * successive commands a reset between each, this function is similar | |
411 | * to doing a reset then a match ROM for the last matched ROM. The | |
412 | * advantage being that the matched ROM step is skipped in favor of the | |
413 | * resume command. The slave must support the command of course. | |
414 | * | |
415 | * If the bus has only one slave, traditionnaly the match ROM is skipped | |
416 | * and a "SKIP ROM" is done for efficiency. On multi-slave busses, this | |
417 | * doesn't work of course, but the resume command is the next best thing. | |
418 | * | |
419 | * The w1 master lock must be held. | |
67dfd54c JFD |
420 | */ |
421 | int w1_reset_resume_command(struct w1_master *dev) | |
422 | { | |
423 | if (w1_reset_bus(dev)) | |
424 | return -1; | |
425 | ||
62909da8 | 426 | w1_write_8(dev, dev->slave_count > 1 ? W1_RESUME_CMD : W1_SKIP_ROM); |
67dfd54c JFD |
427 | return 0; |
428 | } | |
429 | EXPORT_SYMBOL_GPL(w1_reset_resume_command); | |
430 | ||
6a158c0d | 431 | /** |
b3be177a DF |
432 | * w1_next_pullup() - register for a strong pullup |
433 | * @dev: the master device | |
434 | * @delay: time in milliseconds | |
435 | * | |
6a158c0d DF |
436 | * Put out a strong pull-up of the specified duration after the next write |
437 | * operation. Not all hardware supports strong pullups. Hardware that | |
438 | * doesn't support strong pullups will sleep for the given time after the | |
439 | * write operation without a strong pullup. This is a one shot request for | |
440 | * the next write, specifying zero will clear a previous request. | |
441 | * The w1 master lock must be held. | |
442 | * | |
b3be177a | 443 | * Return: 0=success, anything else=error |
6a158c0d DF |
444 | */ |
445 | void w1_next_pullup(struct w1_master *dev, int delay) | |
446 | { | |
447 | dev->pullup_duration = delay; | |
448 | } | |
449 | EXPORT_SYMBOL_GPL(w1_next_pullup); |