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fbf7f7b4 MF |
1 | /* |
2 | * w1_ds28e04.c - w1 family 1C (DS28E04) driver | |
3 | * | |
4 | * Copyright (c) 2012 Markus Franke <franke.m@sebakmt.com> | |
5 | * | |
6 | * This source code is licensed under the GNU General Public License, | |
7 | * Version 2. See the file COPYING for more details. | |
8 | */ | |
9 | ||
10 | #include <linux/kernel.h> | |
11 | #include <linux/module.h> | |
12 | #include <linux/moduleparam.h> | |
13 | #include <linux/device.h> | |
14 | #include <linux/types.h> | |
15 | #include <linux/delay.h> | |
16 | #include <linux/slab.h> | |
17 | #include <linux/crc16.h> | |
18 | #include <linux/uaccess.h> | |
19 | ||
20 | #define CRC16_INIT 0 | |
21 | #define CRC16_VALID 0xb001 | |
22 | ||
23 | #include "../w1.h" | |
24 | #include "../w1_int.h" | |
25 | #include "../w1_family.h" | |
26 | ||
27 | MODULE_LICENSE("GPL"); | |
28 | MODULE_AUTHOR("Markus Franke <franke.m@sebakmt.com>, <franm@hrz.tu-chemnitz.de>"); | |
29 | MODULE_DESCRIPTION("w1 family 1C driver for DS28E04, 4kb EEPROM and PIO"); | |
8d7bda51 | 30 | MODULE_ALIAS("w1-family-" __stringify(W1_FAMILY_DS28E04)); |
fbf7f7b4 MF |
31 | |
32 | /* Allow the strong pullup to be disabled, but default to enabled. | |
33 | * If it was disabled a parasite powered device might not get the required | |
34 | * current to copy the data from the scratchpad to EEPROM. If it is enabled | |
35 | * parasite powered devices have a better chance of getting the current | |
36 | * required. | |
37 | */ | |
38 | static int w1_strong_pullup = 1; | |
39 | module_param_named(strong_pullup, w1_strong_pullup, int, 0); | |
40 | ||
41 | /* enable/disable CRC checking on DS28E04-100 memory accesses */ | |
42 | static char w1_enable_crccheck = 1; | |
43 | ||
44 | #define W1_EEPROM_SIZE 512 | |
45 | #define W1_PAGE_COUNT 16 | |
46 | #define W1_PAGE_SIZE 32 | |
47 | #define W1_PAGE_BITS 5 | |
48 | #define W1_PAGE_MASK 0x1F | |
49 | ||
50 | #define W1_F1C_READ_EEPROM 0xF0 | |
51 | #define W1_F1C_WRITE_SCRATCH 0x0F | |
52 | #define W1_F1C_READ_SCRATCH 0xAA | |
53 | #define W1_F1C_COPY_SCRATCH 0x55 | |
54 | #define W1_F1C_ACCESS_WRITE 0x5A | |
55 | ||
56 | #define W1_1C_REG_LOGIC_STATE 0x220 | |
57 | ||
58 | struct w1_f1C_data { | |
59 | u8 memory[W1_EEPROM_SIZE]; | |
60 | u32 validcrc; | |
61 | }; | |
62 | ||
63 | /** | |
64 | * Check the file size bounds and adjusts count as needed. | |
65 | * This would not be needed if the file size didn't reset to 0 after a write. | |
66 | */ | |
67 | static inline size_t w1_f1C_fix_count(loff_t off, size_t count, size_t size) | |
68 | { | |
69 | if (off > size) | |
70 | return 0; | |
71 | ||
72 | if ((off + count) > size) | |
73 | return size - off; | |
74 | ||
75 | return count; | |
76 | } | |
77 | ||
78 | static int w1_f1C_refresh_block(struct w1_slave *sl, struct w1_f1C_data *data, | |
79 | int block) | |
80 | { | |
81 | u8 wrbuf[3]; | |
82 | int off = block * W1_PAGE_SIZE; | |
83 | ||
84 | if (data->validcrc & (1 << block)) | |
85 | return 0; | |
86 | ||
87 | if (w1_reset_select_slave(sl)) { | |
88 | data->validcrc = 0; | |
89 | return -EIO; | |
90 | } | |
91 | ||
92 | wrbuf[0] = W1_F1C_READ_EEPROM; | |
93 | wrbuf[1] = off & 0xff; | |
94 | wrbuf[2] = off >> 8; | |
95 | w1_write_block(sl->master, wrbuf, 3); | |
96 | w1_read_block(sl->master, &data->memory[off], W1_PAGE_SIZE); | |
97 | ||
98 | /* cache the block if the CRC is valid */ | |
99 | if (crc16(CRC16_INIT, &data->memory[off], W1_PAGE_SIZE) == CRC16_VALID) | |
100 | data->validcrc |= (1 << block); | |
101 | ||
102 | return 0; | |
103 | } | |
104 | ||
105 | static int w1_f1C_read(struct w1_slave *sl, int addr, int len, char *data) | |
106 | { | |
107 | u8 wrbuf[3]; | |
108 | ||
109 | /* read directly from the EEPROM */ | |
110 | if (w1_reset_select_slave(sl)) | |
111 | return -EIO; | |
112 | ||
113 | wrbuf[0] = W1_F1C_READ_EEPROM; | |
114 | wrbuf[1] = addr & 0xff; | |
115 | wrbuf[2] = addr >> 8; | |
116 | ||
117 | w1_write_block(sl->master, wrbuf, sizeof(wrbuf)); | |
118 | return w1_read_block(sl->master, data, len); | |
119 | } | |
120 | ||
fa33a65a GKH |
121 | static ssize_t eeprom_read(struct file *filp, struct kobject *kobj, |
122 | struct bin_attribute *bin_attr, char *buf, | |
123 | loff_t off, size_t count) | |
fbf7f7b4 MF |
124 | { |
125 | struct w1_slave *sl = kobj_to_w1_slave(kobj); | |
126 | struct w1_f1C_data *data = sl->family_data; | |
127 | int i, min_page, max_page; | |
128 | ||
129 | count = w1_f1C_fix_count(off, count, W1_EEPROM_SIZE); | |
130 | if (count == 0) | |
131 | return 0; | |
132 | ||
133 | mutex_lock(&sl->master->mutex); | |
134 | ||
135 | if (w1_enable_crccheck) { | |
136 | min_page = (off >> W1_PAGE_BITS); | |
137 | max_page = (off + count - 1) >> W1_PAGE_BITS; | |
138 | for (i = min_page; i <= max_page; i++) { | |
139 | if (w1_f1C_refresh_block(sl, data, i)) { | |
140 | count = -EIO; | |
141 | goto out_up; | |
142 | } | |
143 | } | |
144 | memcpy(buf, &data->memory[off], count); | |
145 | } else { | |
146 | count = w1_f1C_read(sl, off, count, buf); | |
147 | } | |
148 | ||
149 | out_up: | |
150 | mutex_unlock(&sl->master->mutex); | |
151 | ||
152 | return count; | |
153 | } | |
154 | ||
155 | /** | |
156 | * Writes to the scratchpad and reads it back for verification. | |
157 | * Then copies the scratchpad to EEPROM. | |
158 | * The data must be on one page. | |
159 | * The master must be locked. | |
160 | * | |
161 | * @param sl The slave structure | |
162 | * @param addr Address for the write | |
163 | * @param len length must be <= (W1_PAGE_SIZE - (addr & W1_PAGE_MASK)) | |
164 | * @param data The data to write | |
165 | * @return 0=Success -1=failure | |
166 | */ | |
167 | static int w1_f1C_write(struct w1_slave *sl, int addr, int len, const u8 *data) | |
168 | { | |
169 | u8 wrbuf[4]; | |
170 | u8 rdbuf[W1_PAGE_SIZE + 3]; | |
171 | u8 es = (addr + len - 1) & 0x1f; | |
172 | unsigned int tm = 10; | |
173 | int i; | |
174 | struct w1_f1C_data *f1C = sl->family_data; | |
175 | ||
176 | /* Write the data to the scratchpad */ | |
177 | if (w1_reset_select_slave(sl)) | |
178 | return -1; | |
179 | ||
180 | wrbuf[0] = W1_F1C_WRITE_SCRATCH; | |
181 | wrbuf[1] = addr & 0xff; | |
182 | wrbuf[2] = addr >> 8; | |
183 | ||
184 | w1_write_block(sl->master, wrbuf, 3); | |
185 | w1_write_block(sl->master, data, len); | |
186 | ||
187 | /* Read the scratchpad and verify */ | |
188 | if (w1_reset_select_slave(sl)) | |
189 | return -1; | |
190 | ||
191 | w1_write_8(sl->master, W1_F1C_READ_SCRATCH); | |
192 | w1_read_block(sl->master, rdbuf, len + 3); | |
193 | ||
194 | /* Compare what was read against the data written */ | |
195 | if ((rdbuf[0] != wrbuf[1]) || (rdbuf[1] != wrbuf[2]) || | |
196 | (rdbuf[2] != es) || (memcmp(data, &rdbuf[3], len) != 0)) | |
197 | return -1; | |
198 | ||
199 | /* Copy the scratchpad to EEPROM */ | |
200 | if (w1_reset_select_slave(sl)) | |
201 | return -1; | |
202 | ||
203 | wrbuf[0] = W1_F1C_COPY_SCRATCH; | |
204 | wrbuf[3] = es; | |
205 | ||
206 | for (i = 0; i < sizeof(wrbuf); ++i) { | |
207 | /* issue 10ms strong pullup (or delay) on the last byte | |
208 | for writing the data from the scratchpad to EEPROM */ | |
209 | if (w1_strong_pullup && i == sizeof(wrbuf)-1) | |
210 | w1_next_pullup(sl->master, tm); | |
211 | ||
212 | w1_write_8(sl->master, wrbuf[i]); | |
213 | } | |
214 | ||
215 | if (!w1_strong_pullup) | |
216 | msleep(tm); | |
217 | ||
218 | if (w1_enable_crccheck) { | |
219 | /* invalidate cached data */ | |
220 | f1C->validcrc &= ~(1 << (addr >> W1_PAGE_BITS)); | |
221 | } | |
222 | ||
223 | /* Reset the bus to wake up the EEPROM (this may not be needed) */ | |
224 | w1_reset_bus(sl->master); | |
225 | ||
226 | return 0; | |
227 | } | |
228 | ||
fa33a65a GKH |
229 | static ssize_t eeprom_write(struct file *filp, struct kobject *kobj, |
230 | struct bin_attribute *bin_attr, char *buf, | |
231 | loff_t off, size_t count) | |
fbf7f7b4 MF |
232 | |
233 | { | |
234 | struct w1_slave *sl = kobj_to_w1_slave(kobj); | |
235 | int addr, len, idx; | |
236 | ||
237 | count = w1_f1C_fix_count(off, count, W1_EEPROM_SIZE); | |
238 | if (count == 0) | |
239 | return 0; | |
240 | ||
241 | if (w1_enable_crccheck) { | |
242 | /* can only write full blocks in cached mode */ | |
243 | if ((off & W1_PAGE_MASK) || (count & W1_PAGE_MASK)) { | |
244 | dev_err(&sl->dev, "invalid offset/count off=%d cnt=%zd\n", | |
245 | (int)off, count); | |
246 | return -EINVAL; | |
247 | } | |
248 | ||
249 | /* make sure the block CRCs are valid */ | |
250 | for (idx = 0; idx < count; idx += W1_PAGE_SIZE) { | |
251 | if (crc16(CRC16_INIT, &buf[idx], W1_PAGE_SIZE) | |
252 | != CRC16_VALID) { | |
253 | dev_err(&sl->dev, "bad CRC at offset %d\n", | |
254 | (int)off); | |
255 | return -EINVAL; | |
256 | } | |
257 | } | |
258 | } | |
259 | ||
260 | mutex_lock(&sl->master->mutex); | |
261 | ||
262 | /* Can only write data to one page at a time */ | |
263 | idx = 0; | |
264 | while (idx < count) { | |
265 | addr = off + idx; | |
266 | len = W1_PAGE_SIZE - (addr & W1_PAGE_MASK); | |
267 | if (len > (count - idx)) | |
268 | len = count - idx; | |
269 | ||
270 | if (w1_f1C_write(sl, addr, len, &buf[idx]) < 0) { | |
271 | count = -EIO; | |
272 | goto out_up; | |
273 | } | |
274 | idx += len; | |
275 | } | |
276 | ||
277 | out_up: | |
278 | mutex_unlock(&sl->master->mutex); | |
279 | ||
280 | return count; | |
281 | } | |
282 | ||
fa33a65a GKH |
283 | static BIN_ATTR_RW(eeprom, W1_EEPROM_SIZE); |
284 | ||
285 | static ssize_t pio_read(struct file *filp, struct kobject *kobj, | |
286 | struct bin_attribute *bin_attr, char *buf, loff_t off, | |
287 | size_t count) | |
fbf7f7b4 MF |
288 | |
289 | { | |
290 | struct w1_slave *sl = kobj_to_w1_slave(kobj); | |
291 | int ret; | |
292 | ||
293 | /* check arguments */ | |
294 | if (off != 0 || count != 1 || buf == NULL) | |
295 | return -EINVAL; | |
296 | ||
297 | mutex_lock(&sl->master->mutex); | |
298 | ret = w1_f1C_read(sl, W1_1C_REG_LOGIC_STATE, count, buf); | |
299 | mutex_unlock(&sl->master->mutex); | |
300 | ||
301 | return ret; | |
302 | } | |
303 | ||
fa33a65a GKH |
304 | static ssize_t pio_write(struct file *filp, struct kobject *kobj, |
305 | struct bin_attribute *bin_attr, char *buf, loff_t off, | |
306 | size_t count) | |
fbf7f7b4 MF |
307 | |
308 | { | |
309 | struct w1_slave *sl = kobj_to_w1_slave(kobj); | |
310 | u8 wrbuf[3]; | |
311 | u8 ack; | |
312 | ||
313 | /* check arguments */ | |
314 | if (off != 0 || count != 1 || buf == NULL) | |
315 | return -EINVAL; | |
316 | ||
317 | mutex_lock(&sl->master->mutex); | |
318 | ||
319 | /* Write the PIO data */ | |
320 | if (w1_reset_select_slave(sl)) { | |
321 | mutex_unlock(&sl->master->mutex); | |
322 | return -1; | |
323 | } | |
324 | ||
325 | /* set bit 7..2 to value '1' */ | |
326 | *buf = *buf | 0xFC; | |
327 | ||
328 | wrbuf[0] = W1_F1C_ACCESS_WRITE; | |
329 | wrbuf[1] = *buf; | |
330 | wrbuf[2] = ~(*buf); | |
331 | w1_write_block(sl->master, wrbuf, 3); | |
332 | ||
333 | w1_read_block(sl->master, &ack, sizeof(ack)); | |
334 | ||
335 | mutex_unlock(&sl->master->mutex); | |
336 | ||
337 | /* check for acknowledgement */ | |
338 | if (ack != 0xAA) | |
339 | return -EIO; | |
340 | ||
341 | return count; | |
342 | } | |
343 | ||
fa33a65a GKH |
344 | static BIN_ATTR_RW(pio, 1); |
345 | ||
346 | static ssize_t crccheck_show(struct device *dev, struct device_attribute *attr, | |
347 | char *buf) | |
fbf7f7b4 MF |
348 | { |
349 | if (put_user(w1_enable_crccheck + 0x30, buf)) | |
350 | return -EFAULT; | |
351 | ||
352 | return sizeof(w1_enable_crccheck); | |
353 | } | |
354 | ||
fa33a65a GKH |
355 | static ssize_t crccheck_store(struct device *dev, struct device_attribute *attr, |
356 | const char *buf, size_t count) | |
fbf7f7b4 MF |
357 | { |
358 | char val; | |
359 | ||
360 | if (count != 1 || !buf) | |
361 | return -EINVAL; | |
362 | ||
363 | if (get_user(val, buf)) | |
364 | return -EFAULT; | |
365 | ||
366 | /* convert to decimal */ | |
367 | val = val - 0x30; | |
368 | if (val != 0 && val != 1) | |
369 | return -EINVAL; | |
370 | ||
371 | /* set the new value */ | |
372 | w1_enable_crccheck = val; | |
373 | ||
374 | return sizeof(w1_enable_crccheck); | |
375 | } | |
376 | ||
fa33a65a GKH |
377 | static DEVICE_ATTR_RW(crccheck); |
378 | ||
379 | static struct attribute *w1_f1C_attrs[] = { | |
380 | &dev_attr_crccheck.attr, | |
381 | NULL, | |
fbf7f7b4 MF |
382 | }; |
383 | ||
fa33a65a GKH |
384 | static struct bin_attribute *w1_f1C_bin_attrs[] = { |
385 | &bin_attr_eeprom, | |
386 | &bin_attr_pio, | |
387 | NULL, | |
388 | }; | |
389 | ||
390 | static const struct attribute_group w1_f1C_group = { | |
391 | .attrs = w1_f1C_attrs, | |
392 | .bin_attrs = w1_f1C_bin_attrs, | |
393 | }; | |
394 | ||
395 | static const struct attribute_group *w1_f1C_groups[] = { | |
396 | &w1_f1C_group, | |
397 | NULL, | |
398 | }; | |
fbf7f7b4 MF |
399 | |
400 | static int w1_f1C_add_slave(struct w1_slave *sl) | |
401 | { | |
fbf7f7b4 MF |
402 | struct w1_f1C_data *data = NULL; |
403 | ||
404 | if (w1_enable_crccheck) { | |
405 | data = kzalloc(sizeof(struct w1_f1C_data), GFP_KERNEL); | |
406 | if (!data) | |
407 | return -ENOMEM; | |
408 | sl->family_data = data; | |
409 | } | |
410 | ||
fa33a65a | 411 | return 0; |
fbf7f7b4 MF |
412 | } |
413 | ||
414 | static void w1_f1C_remove_slave(struct w1_slave *sl) | |
415 | { | |
fbf7f7b4 MF |
416 | kfree(sl->family_data); |
417 | sl->family_data = NULL; | |
fbf7f7b4 MF |
418 | } |
419 | ||
420 | static struct w1_family_ops w1_f1C_fops = { | |
421 | .add_slave = w1_f1C_add_slave, | |
422 | .remove_slave = w1_f1C_remove_slave, | |
fa33a65a | 423 | .groups = w1_f1C_groups, |
fbf7f7b4 MF |
424 | }; |
425 | ||
426 | static struct w1_family w1_family_1C = { | |
427 | .fid = W1_FAMILY_DS28E04, | |
428 | .fops = &w1_f1C_fops, | |
429 | }; | |
430 | ||
431 | static int __init w1_f1C_init(void) | |
432 | { | |
433 | return w1_register_family(&w1_family_1C); | |
434 | } | |
435 | ||
436 | static void __exit w1_f1C_fini(void) | |
437 | { | |
438 | w1_unregister_family(&w1_family_1C); | |
439 | } | |
440 | ||
441 | module_init(w1_f1C_init); | |
442 | module_exit(w1_f1C_fini); |