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d8273674 BW |
1 | /* |
2 | * w1_ds2431.c - w1 family 2d (DS2431) driver | |
3 | * | |
4 | * Copyright (c) 2008 Bernhard Weirich <bernhard.weirich@riedel.net> | |
5 | * | |
6 | * Heavily inspired by w1_DS2433 driver from Ben Gardner <bgardner@wabtec.com> | |
7 | * | |
8 | * This source code is licensed under the GNU General Public License, | |
9 | * Version 2. See the file COPYING for more details. | |
10 | */ | |
11 | ||
12 | #include <linux/kernel.h> | |
13 | #include <linux/module.h> | |
14 | #include <linux/moduleparam.h> | |
15 | #include <linux/device.h> | |
16 | #include <linux/types.h> | |
17 | #include <linux/delay.h> | |
18 | ||
19 | #include "../w1.h" | |
20 | #include "../w1_int.h" | |
21 | #include "../w1_family.h" | |
22 | ||
23 | #define W1_F2D_EEPROM_SIZE 128 | |
24 | #define W1_F2D_PAGE_COUNT 4 | |
25 | #define W1_F2D_PAGE_BITS 5 | |
26 | #define W1_F2D_PAGE_SIZE (1<<W1_F2D_PAGE_BITS) | |
27 | #define W1_F2D_PAGE_MASK 0x1F | |
28 | ||
29 | #define W1_F2D_SCRATCH_BITS 3 | |
30 | #define W1_F2D_SCRATCH_SIZE (1<<W1_F2D_SCRATCH_BITS) | |
31 | #define W1_F2D_SCRATCH_MASK (W1_F2D_SCRATCH_SIZE-1) | |
32 | ||
33 | #define W1_F2D_READ_EEPROM 0xF0 | |
34 | #define W1_F2D_WRITE_SCRATCH 0x0F | |
35 | #define W1_F2D_READ_SCRATCH 0xAA | |
36 | #define W1_F2D_COPY_SCRATCH 0x55 | |
37 | ||
38 | ||
39 | #define W1_F2D_TPROG_MS 11 | |
40 | ||
41 | #define W1_F2D_READ_RETRIES 10 | |
42 | #define W1_F2D_READ_MAXLEN 8 | |
43 | ||
44 | /* | |
45 | * Check the file size bounds and adjusts count as needed. | |
46 | * This would not be needed if the file size didn't reset to 0 after a write. | |
47 | */ | |
48 | static inline size_t w1_f2d_fix_count(loff_t off, size_t count, size_t size) | |
49 | { | |
50 | if (off > size) | |
51 | return 0; | |
52 | ||
53 | if ((off + count) > size) | |
54 | return size - off; | |
55 | ||
56 | return count; | |
57 | } | |
58 | ||
59 | /* | |
60 | * Read a block from W1 ROM two times and compares the results. | |
61 | * If they are equal they are returned, otherwise the read | |
62 | * is repeated W1_F2D_READ_RETRIES times. | |
63 | * | |
64 | * count must not exceed W1_F2D_READ_MAXLEN. | |
65 | */ | |
66 | static int w1_f2d_readblock(struct w1_slave *sl, int off, int count, char *buf) | |
67 | { | |
68 | u8 wrbuf[3]; | |
69 | u8 cmp[W1_F2D_READ_MAXLEN]; | |
70 | int tries = W1_F2D_READ_RETRIES; | |
71 | ||
72 | do { | |
73 | wrbuf[0] = W1_F2D_READ_EEPROM; | |
74 | wrbuf[1] = off & 0xff; | |
75 | wrbuf[2] = off >> 8; | |
76 | ||
77 | if (w1_reset_select_slave(sl)) | |
78 | return -1; | |
79 | ||
80 | w1_write_block(sl->master, wrbuf, 3); | |
81 | w1_read_block(sl->master, buf, count); | |
82 | ||
83 | if (w1_reset_select_slave(sl)) | |
84 | return -1; | |
85 | ||
86 | w1_write_block(sl->master, wrbuf, 3); | |
87 | w1_read_block(sl->master, cmp, count); | |
88 | ||
89 | if (!memcmp(cmp, buf, count)) | |
90 | return 0; | |
91 | } while (--tries); | |
92 | ||
93 | dev_err(&sl->dev, "proof reading failed %d times\n", | |
94 | W1_F2D_READ_RETRIES); | |
95 | ||
96 | return -1; | |
97 | } | |
98 | ||
b3c6061d GKH |
99 | static ssize_t eeprom_read(struct file *filp, struct kobject *kobj, |
100 | struct bin_attribute *bin_attr, char *buf, | |
101 | loff_t off, size_t count) | |
d8273674 BW |
102 | { |
103 | struct w1_slave *sl = kobj_to_w1_slave(kobj); | |
104 | int todo = count; | |
105 | ||
106 | count = w1_f2d_fix_count(off, count, W1_F2D_EEPROM_SIZE); | |
107 | if (count == 0) | |
108 | return 0; | |
109 | ||
b02f8bed | 110 | mutex_lock(&sl->master->bus_mutex); |
d8273674 BW |
111 | |
112 | /* read directly from the EEPROM in chunks of W1_F2D_READ_MAXLEN */ | |
113 | while (todo > 0) { | |
114 | int block_read; | |
115 | ||
116 | if (todo >= W1_F2D_READ_MAXLEN) | |
117 | block_read = W1_F2D_READ_MAXLEN; | |
118 | else | |
119 | block_read = todo; | |
120 | ||
121 | if (w1_f2d_readblock(sl, off, block_read, buf) < 0) | |
122 | count = -EIO; | |
123 | ||
124 | todo -= W1_F2D_READ_MAXLEN; | |
125 | buf += W1_F2D_READ_MAXLEN; | |
126 | off += W1_F2D_READ_MAXLEN; | |
127 | } | |
128 | ||
b02f8bed | 129 | mutex_unlock(&sl->master->bus_mutex); |
d8273674 BW |
130 | |
131 | return count; | |
132 | } | |
133 | ||
134 | /* | |
135 | * Writes to the scratchpad and reads it back for verification. | |
136 | * Then copies the scratchpad to EEPROM. | |
137 | * The data must be aligned at W1_F2D_SCRATCH_SIZE bytes and | |
138 | * must be W1_F2D_SCRATCH_SIZE bytes long. | |
139 | * The master must be locked. | |
140 | * | |
141 | * @param sl The slave structure | |
142 | * @param addr Address for the write | |
143 | * @param len length must be <= (W1_F2D_PAGE_SIZE - (addr & W1_F2D_PAGE_MASK)) | |
144 | * @param data The data to write | |
145 | * @return 0=Success -1=failure | |
146 | */ | |
147 | static int w1_f2d_write(struct w1_slave *sl, int addr, int len, const u8 *data) | |
148 | { | |
149 | int tries = W1_F2D_READ_RETRIES; | |
150 | u8 wrbuf[4]; | |
151 | u8 rdbuf[W1_F2D_SCRATCH_SIZE + 3]; | |
152 | u8 es = (addr + len - 1) % W1_F2D_SCRATCH_SIZE; | |
153 | ||
154 | retry: | |
155 | ||
156 | /* Write the data to the scratchpad */ | |
157 | if (w1_reset_select_slave(sl)) | |
158 | return -1; | |
159 | ||
160 | wrbuf[0] = W1_F2D_WRITE_SCRATCH; | |
161 | wrbuf[1] = addr & 0xff; | |
162 | wrbuf[2] = addr >> 8; | |
163 | ||
164 | w1_write_block(sl->master, wrbuf, 3); | |
165 | w1_write_block(sl->master, data, len); | |
166 | ||
167 | /* Read the scratchpad and verify */ | |
168 | if (w1_reset_select_slave(sl)) | |
169 | return -1; | |
170 | ||
171 | w1_write_8(sl->master, W1_F2D_READ_SCRATCH); | |
172 | w1_read_block(sl->master, rdbuf, len + 3); | |
173 | ||
174 | /* Compare what was read against the data written */ | |
175 | if ((rdbuf[0] != wrbuf[1]) || (rdbuf[1] != wrbuf[2]) || | |
176 | (rdbuf[2] != es) || (memcmp(data, &rdbuf[3], len) != 0)) { | |
177 | ||
178 | if (--tries) | |
179 | goto retry; | |
180 | ||
181 | dev_err(&sl->dev, | |
182 | "could not write to eeprom, scratchpad compare failed %d times\n", | |
183 | W1_F2D_READ_RETRIES); | |
184 | ||
185 | return -1; | |
186 | } | |
187 | ||
188 | /* Copy the scratchpad to EEPROM */ | |
189 | if (w1_reset_select_slave(sl)) | |
190 | return -1; | |
191 | ||
192 | wrbuf[0] = W1_F2D_COPY_SCRATCH; | |
193 | wrbuf[3] = es; | |
194 | w1_write_block(sl->master, wrbuf, 4); | |
195 | ||
196 | /* Sleep for tprog ms to wait for the write to complete */ | |
197 | msleep(W1_F2D_TPROG_MS); | |
198 | ||
199 | /* Reset the bus to wake up the EEPROM */ | |
200 | w1_reset_bus(sl->master); | |
201 | ||
202 | return 0; | |
203 | } | |
204 | ||
b3c6061d GKH |
205 | static ssize_t eeprom_write(struct file *filp, struct kobject *kobj, |
206 | struct bin_attribute *bin_attr, char *buf, | |
207 | loff_t off, size_t count) | |
d8273674 BW |
208 | { |
209 | struct w1_slave *sl = kobj_to_w1_slave(kobj); | |
210 | int addr, len; | |
211 | int copy; | |
212 | ||
213 | count = w1_f2d_fix_count(off, count, W1_F2D_EEPROM_SIZE); | |
214 | if (count == 0) | |
215 | return 0; | |
216 | ||
b02f8bed | 217 | mutex_lock(&sl->master->bus_mutex); |
d8273674 BW |
218 | |
219 | /* Can only write data in blocks of the size of the scratchpad */ | |
220 | addr = off; | |
221 | len = count; | |
222 | while (len > 0) { | |
223 | ||
224 | /* if len too short or addr not aligned */ | |
225 | if (len < W1_F2D_SCRATCH_SIZE || addr & W1_F2D_SCRATCH_MASK) { | |
226 | char tmp[W1_F2D_SCRATCH_SIZE]; | |
227 | ||
228 | /* read the block and update the parts to be written */ | |
229 | if (w1_f2d_readblock(sl, addr & ~W1_F2D_SCRATCH_MASK, | |
230 | W1_F2D_SCRATCH_SIZE, tmp)) { | |
231 | count = -EIO; | |
232 | goto out_up; | |
233 | } | |
234 | ||
235 | /* copy at most to the boundary of the PAGE or len */ | |
236 | copy = W1_F2D_SCRATCH_SIZE - | |
237 | (addr & W1_F2D_SCRATCH_MASK); | |
238 | ||
239 | if (copy > len) | |
240 | copy = len; | |
241 | ||
242 | memcpy(&tmp[addr & W1_F2D_SCRATCH_MASK], buf, copy); | |
243 | if (w1_f2d_write(sl, addr & ~W1_F2D_SCRATCH_MASK, | |
244 | W1_F2D_SCRATCH_SIZE, tmp) < 0) { | |
245 | count = -EIO; | |
246 | goto out_up; | |
247 | } | |
248 | } else { | |
249 | ||
250 | copy = W1_F2D_SCRATCH_SIZE; | |
251 | if (w1_f2d_write(sl, addr, copy, buf) < 0) { | |
252 | count = -EIO; | |
253 | goto out_up; | |
254 | } | |
255 | } | |
256 | buf += copy; | |
257 | addr += copy; | |
258 | len -= copy; | |
259 | } | |
260 | ||
261 | out_up: | |
b02f8bed | 262 | mutex_unlock(&sl->master->bus_mutex); |
d8273674 BW |
263 | |
264 | return count; | |
265 | } | |
266 | ||
b3c6061d GKH |
267 | static BIN_ATTR_RW(eeprom, W1_F2D_EEPROM_SIZE); |
268 | ||
269 | static struct bin_attribute *w1_f2d_bin_attrs[] = { | |
270 | &bin_attr_eeprom, | |
271 | NULL, | |
d8273674 BW |
272 | }; |
273 | ||
b3c6061d GKH |
274 | static const struct attribute_group w1_f2d_group = { |
275 | .bin_attrs = w1_f2d_bin_attrs, | |
276 | }; | |
d8273674 | 277 | |
b3c6061d GKH |
278 | static const struct attribute_group *w1_f2d_groups[] = { |
279 | &w1_f2d_group, | |
280 | NULL, | |
281 | }; | |
d8273674 BW |
282 | |
283 | static struct w1_family_ops w1_f2d_fops = { | |
b3c6061d | 284 | .groups = w1_f2d_groups, |
d8273674 BW |
285 | }; |
286 | ||
287 | static struct w1_family w1_family_2d = { | |
288 | .fid = W1_EEPROM_DS2431, | |
289 | .fops = &w1_f2d_fops, | |
290 | }; | |
291 | ||
292 | static int __init w1_f2d_init(void) | |
293 | { | |
294 | return w1_register_family(&w1_family_2d); | |
295 | } | |
296 | ||
297 | static void __exit w1_f2d_fini(void) | |
298 | { | |
299 | w1_unregister_family(&w1_family_2d); | |
300 | } | |
301 | ||
302 | module_init(w1_f2d_init); | |
303 | module_exit(w1_f2d_fini); | |
304 | ||
305 | MODULE_LICENSE("GPL"); | |
306 | MODULE_AUTHOR("Bernhard Weirich <bernhard.weirich@riedel.net>"); | |
307 | MODULE_DESCRIPTION("w1 family 2d driver for DS2431, 1kb EEPROM"); | |
8d7bda51 | 308 | MODULE_ALIAS("w1-family-" __stringify(W1_EEPROM_DS2431)); |