1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | /* |
3 | * w1_ds2805 - w1 family 0d (DS28E05) driver |
4 | * |
5 | * Copyright (c) 2016 Andrew Worsley amworsley@gmail.com |
6 | */ |
7 | |
8 | #include <linux/kernel.h> |
9 | #include <linux/module.h> |
10 | #include <linux/moduleparam.h> |
11 | #include <linux/device.h> |
12 | #include <linux/types.h> |
13 | #include <linux/delay.h> |
14 | |
15 | #include <linux/w1.h> |
16 | |
17 | #define W1_EEPROM_DS2805 0x0D |
18 | |
19 | #define W1_F0D_EEPROM_SIZE 128 |
20 | #define W1_F0D_PAGE_BITS 3 |
21 | #define W1_F0D_PAGE_SIZE (1<<W1_F0D_PAGE_BITS) |
22 | #define W1_F0D_PAGE_MASK 0x0F |
23 | |
24 | #define W1_F0D_SCRATCH_BITS 1 |
25 | #define W1_F0D_SCRATCH_SIZE (1<<W1_F0D_SCRATCH_BITS) |
26 | #define W1_F0D_SCRATCH_MASK (W1_F0D_SCRATCH_SIZE-1) |
27 | |
28 | #define W1_F0D_READ_EEPROM 0xF0 |
29 | #define W1_F0D_WRITE_EEPROM 0x55 |
30 | #define W1_F0D_RELEASE 0xFF |
31 | |
32 | #define W1_F0D_CS_OK 0xAA /* Chip Status Ok */ |
33 | |
34 | #define W1_F0D_TPROG_MS 16 |
35 | |
36 | #define W1_F0D_READ_RETRIES 10 |
37 | #define W1_F0D_READ_MAXLEN W1_F0D_EEPROM_SIZE |
38 | |
39 | /* |
40 | * Check the file size bounds and adjusts count as needed. |
41 | * This would not be needed if the file size didn't reset to 0 after a write. |
42 | */ |
43 | static inline size_t w1_f0d_fix_count(loff_t off, size_t count, size_t size) |
44 | { |
45 | if (off > size) |
46 | return 0; |
47 | |
48 | if ((off + count) > size) |
49 | return size - off; |
50 | |
51 | return count; |
52 | } |
53 | |
54 | /* |
55 | * Read a block from W1 ROM two times and compares the results. |
56 | * If they are equal they are returned, otherwise the read |
57 | * is repeated W1_F0D_READ_RETRIES times. |
58 | * |
59 | * count must not exceed W1_F0D_READ_MAXLEN. |
60 | */ |
61 | static int w1_f0d_readblock(struct w1_slave *sl, int off, int count, char *buf) |
62 | { |
63 | u8 wrbuf[3]; |
64 | u8 cmp[W1_F0D_READ_MAXLEN]; |
65 | int tries = W1_F0D_READ_RETRIES; |
66 | |
67 | do { |
68 | wrbuf[0] = W1_F0D_READ_EEPROM; |
69 | wrbuf[1] = off & 0x7f; |
70 | wrbuf[2] = 0; |
71 | |
72 | if (w1_reset_select_slave(sl)) |
73 | return -1; |
74 | |
75 | w1_write_block(sl->master, wrbuf, sizeof(wrbuf)); |
76 | w1_read_block(sl->master, buf, count); |
77 | |
78 | if (w1_reset_select_slave(sl)) |
79 | return -1; |
80 | |
81 | w1_write_block(sl->master, wrbuf, sizeof(wrbuf)); |
82 | w1_read_block(sl->master, cmp, count); |
83 | |
84 | if (!memcmp(p: cmp, q: buf, size: count)) |
85 | return 0; |
86 | } while (--tries); |
87 | |
88 | dev_err(&sl->dev, "proof reading failed %d times\n" , |
89 | W1_F0D_READ_RETRIES); |
90 | |
91 | return -1; |
92 | } |
93 | |
94 | static ssize_t w1_f0d_read_bin(struct file *filp, struct kobject *kobj, |
95 | struct bin_attribute *bin_attr, |
96 | char *buf, loff_t off, size_t count) |
97 | { |
98 | struct w1_slave *sl = kobj_to_w1_slave(kobj); |
99 | int todo = count; |
100 | |
101 | count = w1_f0d_fix_count(off, count, W1_F0D_EEPROM_SIZE); |
102 | if (count == 0) |
103 | return 0; |
104 | |
105 | mutex_lock(&sl->master->mutex); |
106 | |
107 | /* read directly from the EEPROM in chunks of W1_F0D_READ_MAXLEN */ |
108 | while (todo > 0) { |
109 | int block_read; |
110 | |
111 | if (todo >= W1_F0D_READ_MAXLEN) |
112 | block_read = W1_F0D_READ_MAXLEN; |
113 | else |
114 | block_read = todo; |
115 | |
116 | if (w1_f0d_readblock(sl, off, count: block_read, buf) < 0) { |
117 | count = -EIO; |
118 | break; |
119 | } |
120 | |
121 | todo -= W1_F0D_READ_MAXLEN; |
122 | buf += W1_F0D_READ_MAXLEN; |
123 | off += W1_F0D_READ_MAXLEN; |
124 | } |
125 | |
126 | mutex_unlock(lock: &sl->master->mutex); |
127 | |
128 | return count; |
129 | } |
130 | |
131 | /* |
132 | * Writes to the scratchpad and reads it back for verification. |
133 | * Then copies the scratchpad to EEPROM. |
134 | * The data must be aligned at W1_F0D_SCRATCH_SIZE bytes and |
135 | * must be W1_F0D_SCRATCH_SIZE bytes long. |
136 | * The master must be locked. |
137 | * |
138 | * @param sl The slave structure |
139 | * @param addr Address for the write |
140 | * @param len length must be <= (W1_F0D_PAGE_SIZE - (addr & W1_F0D_PAGE_MASK)) |
141 | * @param data The data to write |
142 | * @return 0=Success -1=failure |
143 | */ |
144 | static int w1_f0d_write(struct w1_slave *sl, int addr, int len, const u8 *data) |
145 | { |
146 | int tries = W1_F0D_READ_RETRIES; |
147 | u8 wrbuf[3]; |
148 | u8 rdbuf[W1_F0D_SCRATCH_SIZE]; |
149 | u8 cs; |
150 | |
151 | if ((addr & 1) || (len != 2)) { |
152 | dev_err(&sl->dev, "%s: bad addr/len - addr=%#x len=%d\n" , |
153 | __func__, addr, len); |
154 | return -1; |
155 | } |
156 | |
157 | retry: |
158 | |
159 | /* Write the data to the scratchpad */ |
160 | if (w1_reset_select_slave(sl)) |
161 | return -1; |
162 | |
163 | wrbuf[0] = W1_F0D_WRITE_EEPROM; |
164 | wrbuf[1] = addr & 0xff; |
165 | wrbuf[2] = 0xff; /* ?? from Example */ |
166 | |
167 | w1_write_block(sl->master, wrbuf, sizeof(wrbuf)); |
168 | w1_write_block(sl->master, data, len); |
169 | |
170 | w1_read_block(sl->master, rdbuf, sizeof(rdbuf)); |
171 | /* Compare what was read against the data written */ |
172 | if ((rdbuf[0] != data[0]) || (rdbuf[1] != data[1])) { |
173 | |
174 | if (--tries) |
175 | goto retry; |
176 | |
177 | dev_err(&sl->dev, |
178 | "could not write to eeprom, scratchpad compare failed %d times\n" , |
179 | W1_F0D_READ_RETRIES); |
180 | pr_info("%s: rdbuf = %#x %#x data = %#x %#x\n" , |
181 | __func__, rdbuf[0], rdbuf[1], data[0], data[1]); |
182 | |
183 | return -1; |
184 | } |
185 | |
186 | /* Trigger write out to EEPROM */ |
187 | w1_write_8(sl->master, W1_F0D_RELEASE); |
188 | |
189 | /* Sleep for tprog ms to wait for the write to complete */ |
190 | msleep(W1_F0D_TPROG_MS); |
191 | |
192 | /* Check CS (Command Status) == 0xAA ? */ |
193 | cs = w1_read_8(sl->master); |
194 | if (cs != W1_F0D_CS_OK) { |
195 | dev_err(&sl->dev, "save to eeprom failed = CS=%#x\n" , cs); |
196 | return -1; |
197 | } |
198 | |
199 | return 0; |
200 | } |
201 | |
202 | static ssize_t w1_f0d_write_bin(struct file *filp, struct kobject *kobj, |
203 | struct bin_attribute *bin_attr, |
204 | char *buf, loff_t off, size_t count) |
205 | { |
206 | struct w1_slave *sl = kobj_to_w1_slave(kobj); |
207 | int addr, len; |
208 | int copy; |
209 | |
210 | count = w1_f0d_fix_count(off, count, W1_F0D_EEPROM_SIZE); |
211 | if (count == 0) |
212 | return 0; |
213 | |
214 | mutex_lock(&sl->master->mutex); |
215 | |
216 | /* Can only write data in blocks of the size of the scratchpad */ |
217 | addr = off; |
218 | len = count; |
219 | while (len > 0) { |
220 | |
221 | /* if len too short or addr not aligned */ |
222 | if (len < W1_F0D_SCRATCH_SIZE || addr & W1_F0D_SCRATCH_MASK) { |
223 | char tmp[W1_F0D_SCRATCH_SIZE]; |
224 | |
225 | /* read the block and update the parts to be written */ |
226 | if (w1_f0d_readblock(sl, off: addr & ~W1_F0D_SCRATCH_MASK, |
227 | W1_F0D_SCRATCH_SIZE, buf: tmp)) { |
228 | count = -EIO; |
229 | goto out_up; |
230 | } |
231 | |
232 | /* copy at most to the boundary of the PAGE or len */ |
233 | copy = W1_F0D_SCRATCH_SIZE - |
234 | (addr & W1_F0D_SCRATCH_MASK); |
235 | |
236 | if (copy > len) |
237 | copy = len; |
238 | |
239 | memcpy(&tmp[addr & W1_F0D_SCRATCH_MASK], buf, copy); |
240 | if (w1_f0d_write(sl, addr: addr & ~W1_F0D_SCRATCH_MASK, |
241 | W1_F0D_SCRATCH_SIZE, data: tmp) < 0) { |
242 | count = -EIO; |
243 | goto out_up; |
244 | } |
245 | } else { |
246 | |
247 | copy = W1_F0D_SCRATCH_SIZE; |
248 | if (w1_f0d_write(sl, addr, len: copy, data: buf) < 0) { |
249 | count = -EIO; |
250 | goto out_up; |
251 | } |
252 | } |
253 | buf += copy; |
254 | addr += copy; |
255 | len -= copy; |
256 | } |
257 | |
258 | out_up: |
259 | mutex_unlock(lock: &sl->master->mutex); |
260 | |
261 | return count; |
262 | } |
263 | |
264 | static struct bin_attribute w1_f0d_bin_attr = { |
265 | .attr = { |
266 | .name = "eeprom" , |
267 | .mode = 0644, |
268 | }, |
269 | .size = W1_F0D_EEPROM_SIZE, |
270 | .read = w1_f0d_read_bin, |
271 | .write = w1_f0d_write_bin, |
272 | }; |
273 | |
274 | static int w1_f0d_add_slave(struct w1_slave *sl) |
275 | { |
276 | return sysfs_create_bin_file(kobj: &sl->dev.kobj, attr: &w1_f0d_bin_attr); |
277 | } |
278 | |
279 | static void w1_f0d_remove_slave(struct w1_slave *sl) |
280 | { |
281 | sysfs_remove_bin_file(kobj: &sl->dev.kobj, attr: &w1_f0d_bin_attr); |
282 | } |
283 | |
284 | static const struct w1_family_ops w1_f0d_fops = { |
285 | .add_slave = w1_f0d_add_slave, |
286 | .remove_slave = w1_f0d_remove_slave, |
287 | }; |
288 | |
289 | static struct w1_family w1_family_0d = { |
290 | .fid = W1_EEPROM_DS2805, |
291 | .fops = &w1_f0d_fops, |
292 | }; |
293 | |
294 | module_w1_family(w1_family_0d); |
295 | |
296 | MODULE_LICENSE("GPL" ); |
297 | MODULE_AUTHOR("Andrew Worsley amworsley@gmail.com" ); |
298 | MODULE_DESCRIPTION("w1 family 0d driver for DS2805, 1kb EEPROM" ); |
299 | |