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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 | ||
de0d6dbd AD |
23 | #include <linux/w1.h> |
24 | ||
25 | #define W1_FAMILY_DS28E04 0x1C | |
fbf7f7b4 | 26 | |
fbf7f7b4 MF |
27 | /* Allow the strong pullup to be disabled, but default to enabled. |
28 | * If it was disabled a parasite powered device might not get the required | |
29 | * current to copy the data from the scratchpad to EEPROM. If it is enabled | |
30 | * parasite powered devices have a better chance of getting the current | |
31 | * required. | |
32 | */ | |
33 | static int w1_strong_pullup = 1; | |
34 | module_param_named(strong_pullup, w1_strong_pullup, int, 0); | |
35 | ||
36 | /* enable/disable CRC checking on DS28E04-100 memory accesses */ | |
37 | static char w1_enable_crccheck = 1; | |
38 | ||
39 | #define W1_EEPROM_SIZE 512 | |
40 | #define W1_PAGE_COUNT 16 | |
41 | #define W1_PAGE_SIZE 32 | |
42 | #define W1_PAGE_BITS 5 | |
43 | #define W1_PAGE_MASK 0x1F | |
44 | ||
45 | #define W1_F1C_READ_EEPROM 0xF0 | |
46 | #define W1_F1C_WRITE_SCRATCH 0x0F | |
47 | #define W1_F1C_READ_SCRATCH 0xAA | |
48 | #define W1_F1C_COPY_SCRATCH 0x55 | |
49 | #define W1_F1C_ACCESS_WRITE 0x5A | |
50 | ||
51 | #define W1_1C_REG_LOGIC_STATE 0x220 | |
52 | ||
53 | struct w1_f1C_data { | |
54 | u8 memory[W1_EEPROM_SIZE]; | |
55 | u32 validcrc; | |
56 | }; | |
57 | ||
58 | /** | |
59 | * Check the file size bounds and adjusts count as needed. | |
60 | * This would not be needed if the file size didn't reset to 0 after a write. | |
61 | */ | |
62 | static inline size_t w1_f1C_fix_count(loff_t off, size_t count, size_t size) | |
63 | { | |
64 | if (off > size) | |
65 | return 0; | |
66 | ||
67 | if ((off + count) > size) | |
68 | return size - off; | |
69 | ||
70 | return count; | |
71 | } | |
72 | ||
73 | static int w1_f1C_refresh_block(struct w1_slave *sl, struct w1_f1C_data *data, | |
74 | int block) | |
75 | { | |
76 | u8 wrbuf[3]; | |
77 | int off = block * W1_PAGE_SIZE; | |
78 | ||
79 | if (data->validcrc & (1 << block)) | |
80 | return 0; | |
81 | ||
82 | if (w1_reset_select_slave(sl)) { | |
83 | data->validcrc = 0; | |
84 | return -EIO; | |
85 | } | |
86 | ||
87 | wrbuf[0] = W1_F1C_READ_EEPROM; | |
88 | wrbuf[1] = off & 0xff; | |
89 | wrbuf[2] = off >> 8; | |
90 | w1_write_block(sl->master, wrbuf, 3); | |
91 | w1_read_block(sl->master, &data->memory[off], W1_PAGE_SIZE); | |
92 | ||
93 | /* cache the block if the CRC is valid */ | |
94 | if (crc16(CRC16_INIT, &data->memory[off], W1_PAGE_SIZE) == CRC16_VALID) | |
95 | data->validcrc |= (1 << block); | |
96 | ||
97 | return 0; | |
98 | } | |
99 | ||
100 | static int w1_f1C_read(struct w1_slave *sl, int addr, int len, char *data) | |
101 | { | |
102 | u8 wrbuf[3]; | |
103 | ||
104 | /* read directly from the EEPROM */ | |
105 | if (w1_reset_select_slave(sl)) | |
106 | return -EIO; | |
107 | ||
108 | wrbuf[0] = W1_F1C_READ_EEPROM; | |
109 | wrbuf[1] = addr & 0xff; | |
110 | wrbuf[2] = addr >> 8; | |
111 | ||
112 | w1_write_block(sl->master, wrbuf, sizeof(wrbuf)); | |
113 | return w1_read_block(sl->master, data, len); | |
114 | } | |
115 | ||
fa33a65a GKH |
116 | static ssize_t eeprom_read(struct file *filp, struct kobject *kobj, |
117 | struct bin_attribute *bin_attr, char *buf, | |
118 | loff_t off, size_t count) | |
fbf7f7b4 MF |
119 | { |
120 | struct w1_slave *sl = kobj_to_w1_slave(kobj); | |
121 | struct w1_f1C_data *data = sl->family_data; | |
122 | int i, min_page, max_page; | |
123 | ||
124 | count = w1_f1C_fix_count(off, count, W1_EEPROM_SIZE); | |
125 | if (count == 0) | |
126 | return 0; | |
127 | ||
128 | mutex_lock(&sl->master->mutex); | |
129 | ||
130 | if (w1_enable_crccheck) { | |
131 | min_page = (off >> W1_PAGE_BITS); | |
132 | max_page = (off + count - 1) >> W1_PAGE_BITS; | |
133 | for (i = min_page; i <= max_page; i++) { | |
134 | if (w1_f1C_refresh_block(sl, data, i)) { | |
135 | count = -EIO; | |
136 | goto out_up; | |
137 | } | |
138 | } | |
139 | memcpy(buf, &data->memory[off], count); | |
140 | } else { | |
141 | count = w1_f1C_read(sl, off, count, buf); | |
142 | } | |
143 | ||
144 | out_up: | |
145 | mutex_unlock(&sl->master->mutex); | |
146 | ||
147 | return count; | |
148 | } | |
149 | ||
150 | /** | |
151 | * Writes to the scratchpad and reads it back for verification. | |
152 | * Then copies the scratchpad to EEPROM. | |
153 | * The data must be on one page. | |
154 | * The master must be locked. | |
155 | * | |
156 | * @param sl The slave structure | |
157 | * @param addr Address for the write | |
158 | * @param len length must be <= (W1_PAGE_SIZE - (addr & W1_PAGE_MASK)) | |
159 | * @param data The data to write | |
160 | * @return 0=Success -1=failure | |
161 | */ | |
162 | static int w1_f1C_write(struct w1_slave *sl, int addr, int len, const u8 *data) | |
163 | { | |
164 | u8 wrbuf[4]; | |
165 | u8 rdbuf[W1_PAGE_SIZE + 3]; | |
166 | u8 es = (addr + len - 1) & 0x1f; | |
167 | unsigned int tm = 10; | |
168 | int i; | |
169 | struct w1_f1C_data *f1C = sl->family_data; | |
170 | ||
171 | /* Write the data to the scratchpad */ | |
172 | if (w1_reset_select_slave(sl)) | |
173 | return -1; | |
174 | ||
175 | wrbuf[0] = W1_F1C_WRITE_SCRATCH; | |
176 | wrbuf[1] = addr & 0xff; | |
177 | wrbuf[2] = addr >> 8; | |
178 | ||
179 | w1_write_block(sl->master, wrbuf, 3); | |
180 | w1_write_block(sl->master, data, len); | |
181 | ||
182 | /* Read the scratchpad and verify */ | |
183 | if (w1_reset_select_slave(sl)) | |
184 | return -1; | |
185 | ||
186 | w1_write_8(sl->master, W1_F1C_READ_SCRATCH); | |
187 | w1_read_block(sl->master, rdbuf, len + 3); | |
188 | ||
189 | /* Compare what was read against the data written */ | |
190 | if ((rdbuf[0] != wrbuf[1]) || (rdbuf[1] != wrbuf[2]) || | |
191 | (rdbuf[2] != es) || (memcmp(data, &rdbuf[3], len) != 0)) | |
192 | return -1; | |
193 | ||
194 | /* Copy the scratchpad to EEPROM */ | |
195 | if (w1_reset_select_slave(sl)) | |
196 | return -1; | |
197 | ||
198 | wrbuf[0] = W1_F1C_COPY_SCRATCH; | |
199 | wrbuf[3] = es; | |
200 | ||
201 | for (i = 0; i < sizeof(wrbuf); ++i) { | |
202 | /* issue 10ms strong pullup (or delay) on the last byte | |
203 | for writing the data from the scratchpad to EEPROM */ | |
204 | if (w1_strong_pullup && i == sizeof(wrbuf)-1) | |
205 | w1_next_pullup(sl->master, tm); | |
206 | ||
207 | w1_write_8(sl->master, wrbuf[i]); | |
208 | } | |
209 | ||
210 | if (!w1_strong_pullup) | |
211 | msleep(tm); | |
212 | ||
213 | if (w1_enable_crccheck) { | |
214 | /* invalidate cached data */ | |
215 | f1C->validcrc &= ~(1 << (addr >> W1_PAGE_BITS)); | |
216 | } | |
217 | ||
218 | /* Reset the bus to wake up the EEPROM (this may not be needed) */ | |
219 | w1_reset_bus(sl->master); | |
220 | ||
221 | return 0; | |
222 | } | |
223 | ||
fa33a65a GKH |
224 | static ssize_t eeprom_write(struct file *filp, struct kobject *kobj, |
225 | struct bin_attribute *bin_attr, char *buf, | |
226 | loff_t off, size_t count) | |
fbf7f7b4 MF |
227 | |
228 | { | |
229 | struct w1_slave *sl = kobj_to_w1_slave(kobj); | |
230 | int addr, len, idx; | |
231 | ||
232 | count = w1_f1C_fix_count(off, count, W1_EEPROM_SIZE); | |
233 | if (count == 0) | |
234 | return 0; | |
235 | ||
236 | if (w1_enable_crccheck) { | |
237 | /* can only write full blocks in cached mode */ | |
238 | if ((off & W1_PAGE_MASK) || (count & W1_PAGE_MASK)) { | |
239 | dev_err(&sl->dev, "invalid offset/count off=%d cnt=%zd\n", | |
240 | (int)off, count); | |
241 | return -EINVAL; | |
242 | } | |
243 | ||
244 | /* make sure the block CRCs are valid */ | |
245 | for (idx = 0; idx < count; idx += W1_PAGE_SIZE) { | |
246 | if (crc16(CRC16_INIT, &buf[idx], W1_PAGE_SIZE) | |
247 | != CRC16_VALID) { | |
248 | dev_err(&sl->dev, "bad CRC at offset %d\n", | |
249 | (int)off); | |
250 | return -EINVAL; | |
251 | } | |
252 | } | |
253 | } | |
254 | ||
255 | mutex_lock(&sl->master->mutex); | |
256 | ||
257 | /* Can only write data to one page at a time */ | |
258 | idx = 0; | |
259 | while (idx < count) { | |
260 | addr = off + idx; | |
261 | len = W1_PAGE_SIZE - (addr & W1_PAGE_MASK); | |
262 | if (len > (count - idx)) | |
263 | len = count - idx; | |
264 | ||
265 | if (w1_f1C_write(sl, addr, len, &buf[idx]) < 0) { | |
266 | count = -EIO; | |
267 | goto out_up; | |
268 | } | |
269 | idx += len; | |
270 | } | |
271 | ||
272 | out_up: | |
273 | mutex_unlock(&sl->master->mutex); | |
274 | ||
275 | return count; | |
276 | } | |
277 | ||
fa33a65a GKH |
278 | static BIN_ATTR_RW(eeprom, W1_EEPROM_SIZE); |
279 | ||
280 | static ssize_t pio_read(struct file *filp, struct kobject *kobj, | |
281 | struct bin_attribute *bin_attr, char *buf, loff_t off, | |
282 | size_t count) | |
fbf7f7b4 MF |
283 | |
284 | { | |
285 | struct w1_slave *sl = kobj_to_w1_slave(kobj); | |
286 | int ret; | |
287 | ||
288 | /* check arguments */ | |
289 | if (off != 0 || count != 1 || buf == NULL) | |
290 | return -EINVAL; | |
291 | ||
292 | mutex_lock(&sl->master->mutex); | |
293 | ret = w1_f1C_read(sl, W1_1C_REG_LOGIC_STATE, count, buf); | |
294 | mutex_unlock(&sl->master->mutex); | |
295 | ||
296 | return ret; | |
297 | } | |
298 | ||
fa33a65a GKH |
299 | static ssize_t pio_write(struct file *filp, struct kobject *kobj, |
300 | struct bin_attribute *bin_attr, char *buf, loff_t off, | |
301 | size_t count) | |
fbf7f7b4 MF |
302 | |
303 | { | |
304 | struct w1_slave *sl = kobj_to_w1_slave(kobj); | |
305 | u8 wrbuf[3]; | |
306 | u8 ack; | |
307 | ||
308 | /* check arguments */ | |
309 | if (off != 0 || count != 1 || buf == NULL) | |
310 | return -EINVAL; | |
311 | ||
312 | mutex_lock(&sl->master->mutex); | |
313 | ||
314 | /* Write the PIO data */ | |
315 | if (w1_reset_select_slave(sl)) { | |
316 | mutex_unlock(&sl->master->mutex); | |
317 | return -1; | |
318 | } | |
319 | ||
320 | /* set bit 7..2 to value '1' */ | |
321 | *buf = *buf | 0xFC; | |
322 | ||
323 | wrbuf[0] = W1_F1C_ACCESS_WRITE; | |
324 | wrbuf[1] = *buf; | |
325 | wrbuf[2] = ~(*buf); | |
326 | w1_write_block(sl->master, wrbuf, 3); | |
327 | ||
328 | w1_read_block(sl->master, &ack, sizeof(ack)); | |
329 | ||
330 | mutex_unlock(&sl->master->mutex); | |
331 | ||
332 | /* check for acknowledgement */ | |
333 | if (ack != 0xAA) | |
334 | return -EIO; | |
335 | ||
336 | return count; | |
337 | } | |
338 | ||
fa33a65a GKH |
339 | static BIN_ATTR_RW(pio, 1); |
340 | ||
341 | static ssize_t crccheck_show(struct device *dev, struct device_attribute *attr, | |
342 | char *buf) | |
fbf7f7b4 MF |
343 | { |
344 | if (put_user(w1_enable_crccheck + 0x30, buf)) | |
345 | return -EFAULT; | |
346 | ||
347 | return sizeof(w1_enable_crccheck); | |
348 | } | |
349 | ||
fa33a65a GKH |
350 | static ssize_t crccheck_store(struct device *dev, struct device_attribute *attr, |
351 | const char *buf, size_t count) | |
fbf7f7b4 MF |
352 | { |
353 | char val; | |
354 | ||
355 | if (count != 1 || !buf) | |
356 | return -EINVAL; | |
357 | ||
358 | if (get_user(val, buf)) | |
359 | return -EFAULT; | |
360 | ||
361 | /* convert to decimal */ | |
362 | val = val - 0x30; | |
363 | if (val != 0 && val != 1) | |
364 | return -EINVAL; | |
365 | ||
366 | /* set the new value */ | |
367 | w1_enable_crccheck = val; | |
368 | ||
369 | return sizeof(w1_enable_crccheck); | |
370 | } | |
371 | ||
fa33a65a GKH |
372 | static DEVICE_ATTR_RW(crccheck); |
373 | ||
374 | static struct attribute *w1_f1C_attrs[] = { | |
375 | &dev_attr_crccheck.attr, | |
376 | NULL, | |
fbf7f7b4 MF |
377 | }; |
378 | ||
fa33a65a GKH |
379 | static struct bin_attribute *w1_f1C_bin_attrs[] = { |
380 | &bin_attr_eeprom, | |
381 | &bin_attr_pio, | |
382 | NULL, | |
383 | }; | |
384 | ||
385 | static const struct attribute_group w1_f1C_group = { | |
386 | .attrs = w1_f1C_attrs, | |
387 | .bin_attrs = w1_f1C_bin_attrs, | |
388 | }; | |
389 | ||
390 | static const struct attribute_group *w1_f1C_groups[] = { | |
391 | &w1_f1C_group, | |
392 | NULL, | |
393 | }; | |
fbf7f7b4 MF |
394 | |
395 | static int w1_f1C_add_slave(struct w1_slave *sl) | |
396 | { | |
fbf7f7b4 MF |
397 | struct w1_f1C_data *data = NULL; |
398 | ||
399 | if (w1_enable_crccheck) { | |
400 | data = kzalloc(sizeof(struct w1_f1C_data), GFP_KERNEL); | |
401 | if (!data) | |
402 | return -ENOMEM; | |
403 | sl->family_data = data; | |
404 | } | |
405 | ||
fa33a65a | 406 | return 0; |
fbf7f7b4 MF |
407 | } |
408 | ||
409 | static void w1_f1C_remove_slave(struct w1_slave *sl) | |
410 | { | |
fbf7f7b4 MF |
411 | kfree(sl->family_data); |
412 | sl->family_data = NULL; | |
fbf7f7b4 MF |
413 | } |
414 | ||
415 | static struct w1_family_ops w1_f1C_fops = { | |
416 | .add_slave = w1_f1C_add_slave, | |
417 | .remove_slave = w1_f1C_remove_slave, | |
fa33a65a | 418 | .groups = w1_f1C_groups, |
fbf7f7b4 MF |
419 | }; |
420 | ||
421 | static struct w1_family w1_family_1C = { | |
422 | .fid = W1_FAMILY_DS28E04, | |
423 | .fops = &w1_f1C_fops, | |
424 | }; | |
939fc832 | 425 | module_w1_family(w1_family_1C); |
50fa2951 AD |
426 | |
427 | MODULE_AUTHOR("Markus Franke <franke.m@sebakmt.com>, <franm@hrz.tu-chemnitz.de>"); | |
428 | MODULE_DESCRIPTION("w1 family 1C driver for DS28E04, 4kb EEPROM and PIO"); | |
429 | MODULE_LICENSE("GPL"); | |
430 | MODULE_ALIAS("w1-family-" __stringify(W1_FAMILY_DS28E04)); |