1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | /* |
3 | * w1_ds2430.c - w1 family 14 (DS2430) driver |
4 | ** |
5 | * Copyright (c) 2019 Angelo Dureghello <angelo.dureghello@timesys.com> |
6 | * |
7 | * Cloned and modified from ds2431 |
8 | * Copyright (c) 2008 Bernhard Weirich <bernhard.weirich@riedel.net> |
9 | * |
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 <linux/w1.h> |
20 | |
21 | #define W1_EEPROM_DS2430 0x14 |
22 | |
23 | #define W1_F14_EEPROM_SIZE 32 |
24 | #define W1_F14_PAGE_COUNT 1 |
25 | #define W1_F14_PAGE_BITS 5 |
26 | #define W1_F14_PAGE_SIZE (1 << W1_F14_PAGE_BITS) |
27 | #define W1_F14_PAGE_MASK 0x1F |
28 | |
29 | #define W1_F14_SCRATCH_BITS 5 |
30 | #define W1_F14_SCRATCH_SIZE (1 << W1_F14_SCRATCH_BITS) |
31 | #define W1_F14_SCRATCH_MASK (W1_F14_SCRATCH_SIZE-1) |
32 | |
33 | #define W1_F14_READ_EEPROM 0xF0 |
34 | #define W1_F14_WRITE_SCRATCH 0x0F |
35 | #define W1_F14_READ_SCRATCH 0xAA |
36 | #define W1_F14_COPY_SCRATCH 0x55 |
37 | #define W1_F14_VALIDATION_KEY 0xa5 |
38 | |
39 | #define W1_F14_TPROG_MS 11 |
40 | #define W1_F14_READ_RETRIES 10 |
41 | #define W1_F14_READ_MAXLEN W1_F14_SCRATCH_SIZE |
42 | |
43 | /* |
44 | * Check the file size bounds and adjusts count as needed. |
45 | * This would not be needed if the file size didn't reset to 0 after a write. |
46 | */ |
47 | static inline size_t w1_f14_fix_count(loff_t off, size_t count, size_t size) |
48 | { |
49 | if (off > size) |
50 | return 0; |
51 | |
52 | if ((off + count) > size) |
53 | return size - off; |
54 | |
55 | return count; |
56 | } |
57 | |
58 | /* |
59 | * Read a block from W1 ROM two times and compares the results. |
60 | * If they are equal they are returned, otherwise the read |
61 | * is repeated W1_F14_READ_RETRIES times. |
62 | * |
63 | * count must not exceed W1_F14_READ_MAXLEN. |
64 | */ |
65 | static int w1_f14_readblock(struct w1_slave *sl, int off, int count, char *buf) |
66 | { |
67 | u8 wrbuf[2]; |
68 | u8 cmp[W1_F14_READ_MAXLEN]; |
69 | int tries = W1_F14_READ_RETRIES; |
70 | |
71 | do { |
72 | wrbuf[0] = W1_F14_READ_EEPROM; |
73 | wrbuf[1] = off & 0xff; |
74 | |
75 | if (w1_reset_select_slave(sl)) |
76 | return -1; |
77 | |
78 | w1_write_block(sl->master, wrbuf, 2); |
79 | w1_read_block(sl->master, buf, count); |
80 | |
81 | if (w1_reset_select_slave(sl)) |
82 | return -1; |
83 | |
84 | w1_write_block(sl->master, wrbuf, 2); |
85 | w1_read_block(sl->master, cmp, count); |
86 | |
87 | if (!memcmp(p: cmp, q: buf, size: count)) |
88 | return 0; |
89 | } while (--tries); |
90 | |
91 | dev_err(&sl->dev, "proof reading failed %d times\n" , |
92 | W1_F14_READ_RETRIES); |
93 | |
94 | return -1; |
95 | } |
96 | |
97 | static ssize_t eeprom_read(struct file *filp, struct kobject *kobj, |
98 | struct bin_attribute *bin_attr, char *buf, |
99 | loff_t off, size_t count) |
100 | { |
101 | struct w1_slave *sl = kobj_to_w1_slave(kobj); |
102 | int todo = count; |
103 | |
104 | count = w1_f14_fix_count(off, count, W1_F14_EEPROM_SIZE); |
105 | if (count == 0) |
106 | return 0; |
107 | |
108 | mutex_lock(&sl->master->bus_mutex); |
109 | |
110 | /* read directly from the EEPROM in chunks of W1_F14_READ_MAXLEN */ |
111 | while (todo > 0) { |
112 | int block_read; |
113 | |
114 | if (todo >= W1_F14_READ_MAXLEN) |
115 | block_read = W1_F14_READ_MAXLEN; |
116 | else |
117 | block_read = todo; |
118 | |
119 | if (w1_f14_readblock(sl, off, count: block_read, buf) < 0) |
120 | count = -EIO; |
121 | |
122 | todo -= W1_F14_READ_MAXLEN; |
123 | buf += W1_F14_READ_MAXLEN; |
124 | off += W1_F14_READ_MAXLEN; |
125 | } |
126 | |
127 | mutex_unlock(lock: &sl->master->bus_mutex); |
128 | |
129 | return count; |
130 | } |
131 | |
132 | /* |
133 | * Writes to the scratchpad and reads it back for verification. |
134 | * Then copies the scratchpad to EEPROM. |
135 | * The data must be aligned at W1_F14_SCRATCH_SIZE bytes and |
136 | * must be W1_F14_SCRATCH_SIZE bytes long. |
137 | * The master must be locked. |
138 | * |
139 | * @param sl The slave structure |
140 | * @param addr Address for the write |
141 | * @param len length must be <= (W1_F14_PAGE_SIZE - (addr & W1_F14_PAGE_MASK)) |
142 | * @param data The data to write |
143 | * @return 0=Success -1=failure |
144 | */ |
145 | static int w1_f14_write(struct w1_slave *sl, int addr, int len, const u8 *data) |
146 | { |
147 | int tries = W1_F14_READ_RETRIES; |
148 | u8 wrbuf[2]; |
149 | u8 rdbuf[W1_F14_SCRATCH_SIZE + 3]; |
150 | |
151 | retry: |
152 | |
153 | /* Write the data to the scratchpad */ |
154 | if (w1_reset_select_slave(sl)) |
155 | return -1; |
156 | |
157 | wrbuf[0] = W1_F14_WRITE_SCRATCH; |
158 | wrbuf[1] = addr & 0xff; |
159 | |
160 | w1_write_block(sl->master, wrbuf, 2); |
161 | w1_write_block(sl->master, data, len); |
162 | |
163 | /* Read the scratchpad and verify */ |
164 | if (w1_reset_select_slave(sl)) |
165 | return -1; |
166 | |
167 | w1_write_8(sl->master, W1_F14_READ_SCRATCH); |
168 | w1_read_block(sl->master, rdbuf, len + 2); |
169 | |
170 | /* |
171 | * Compare what was read against the data written |
172 | * Note: on read scratchpad, device returns 2 bulk 0xff bytes, |
173 | * to be discarded. |
174 | */ |
175 | if ((memcmp(p: data, q: &rdbuf[2], size: len) != 0)) { |
176 | |
177 | if (--tries) |
178 | goto retry; |
179 | |
180 | dev_err(&sl->dev, |
181 | "could not write to eeprom, scratchpad compare failed %d times\n" , |
182 | W1_F14_READ_RETRIES); |
183 | |
184 | return -1; |
185 | } |
186 | |
187 | /* Copy the scratchpad to EEPROM */ |
188 | if (w1_reset_select_slave(sl)) |
189 | return -1; |
190 | |
191 | wrbuf[0] = W1_F14_COPY_SCRATCH; |
192 | wrbuf[1] = W1_F14_VALIDATION_KEY; |
193 | w1_write_block(sl->master, wrbuf, 2); |
194 | |
195 | /* Sleep for tprog ms to wait for the write to complete */ |
196 | msleep(W1_F14_TPROG_MS); |
197 | |
198 | /* Reset the bus to wake up the EEPROM */ |
199 | w1_reset_bus(sl->master); |
200 | |
201 | return 0; |
202 | } |
203 | |
204 | static ssize_t eeprom_write(struct file *filp, struct kobject *kobj, |
205 | struct bin_attribute *bin_attr, char *buf, |
206 | loff_t off, size_t count) |
207 | { |
208 | struct w1_slave *sl = kobj_to_w1_slave(kobj); |
209 | int addr, len; |
210 | int copy; |
211 | |
212 | count = w1_f14_fix_count(off, count, W1_F14_EEPROM_SIZE); |
213 | if (count == 0) |
214 | return 0; |
215 | |
216 | mutex_lock(&sl->master->bus_mutex); |
217 | |
218 | /* Can only write data in blocks of the size of the scratchpad */ |
219 | addr = off; |
220 | len = count; |
221 | while (len > 0) { |
222 | |
223 | /* if len too short or addr not aligned */ |
224 | if (len < W1_F14_SCRATCH_SIZE || addr & W1_F14_SCRATCH_MASK) { |
225 | char tmp[W1_F14_SCRATCH_SIZE]; |
226 | |
227 | /* read the block and update the parts to be written */ |
228 | if (w1_f14_readblock(sl, off: addr & ~W1_F14_SCRATCH_MASK, |
229 | W1_F14_SCRATCH_SIZE, buf: tmp)) { |
230 | count = -EIO; |
231 | goto out_up; |
232 | } |
233 | |
234 | /* copy at most to the boundary of the PAGE or len */ |
235 | copy = W1_F14_SCRATCH_SIZE - |
236 | (addr & W1_F14_SCRATCH_MASK); |
237 | |
238 | if (copy > len) |
239 | copy = len; |
240 | |
241 | memcpy(&tmp[addr & W1_F14_SCRATCH_MASK], buf, copy); |
242 | if (w1_f14_write(sl, addr: addr & ~W1_F14_SCRATCH_MASK, |
243 | W1_F14_SCRATCH_SIZE, data: tmp) < 0) { |
244 | count = -EIO; |
245 | goto out_up; |
246 | } |
247 | } else { |
248 | |
249 | copy = W1_F14_SCRATCH_SIZE; |
250 | if (w1_f14_write(sl, addr, len: copy, data: buf) < 0) { |
251 | count = -EIO; |
252 | goto out_up; |
253 | } |
254 | } |
255 | buf += copy; |
256 | addr += copy; |
257 | len -= copy; |
258 | } |
259 | |
260 | out_up: |
261 | mutex_unlock(lock: &sl->master->bus_mutex); |
262 | |
263 | return count; |
264 | } |
265 | |
266 | static BIN_ATTR_RW(eeprom, W1_F14_EEPROM_SIZE); |
267 | |
268 | static struct bin_attribute *w1_f14_bin_attrs[] = { |
269 | &bin_attr_eeprom, |
270 | NULL, |
271 | }; |
272 | |
273 | static const struct attribute_group w1_f14_group = { |
274 | .bin_attrs = w1_f14_bin_attrs, |
275 | }; |
276 | |
277 | static const struct attribute_group *w1_f14_groups[] = { |
278 | &w1_f14_group, |
279 | NULL, |
280 | }; |
281 | |
282 | static const struct w1_family_ops w1_f14_fops = { |
283 | .groups = w1_f14_groups, |
284 | }; |
285 | |
286 | static struct w1_family w1_family_14 = { |
287 | .fid = W1_EEPROM_DS2430, |
288 | .fops = &w1_f14_fops, |
289 | }; |
290 | module_w1_family(w1_family_14); |
291 | |
292 | MODULE_AUTHOR("Angelo Dureghello <angelo.dureghello@timesys.com>" ); |
293 | MODULE_DESCRIPTION("w1 family 14 driver for DS2430, 256b EEPROM" ); |
294 | MODULE_LICENSE("GPL" ); |
295 | MODULE_ALIAS("w1-family-" __stringify(W1_EEPROM_DS2430)); |
296 | |