1 /*
2 * w1_ds2433.c - w1 family 23 (DS2433) driver
3 *
4 * Copyright (c) 2005 Ben Gardner <bgardner@wabtec.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 #ifdef CONFIG_W1_SLAVE_DS2433_CRC
17 #include <linux/crc16.h>
18
19 #define CRC16_INIT 0
20 #define CRC16_VALID 0xb001
21
22 #endif
23
24 #include "../w1.h"
25 #include "../w1_int.h"
26 #include "../w1_family.h"
27
28 MODULE_LICENSE("GPL");
29 MODULE_AUTHOR("Ben Gardner <bgardner@wabtec.com>");
30 MODULE_DESCRIPTION("w1 family 23 driver for DS2433, 4kb EEPROM");
31
32 #define W1_EEPROM_SIZE 512
33 #define W1_PAGE_COUNT 16
34 #define W1_PAGE_SIZE 32
35 #define W1_PAGE_BITS 5
36 #define W1_PAGE_MASK 0x1F
37
38 #define W1_F23_TIME 300
39
40 #define W1_F23_READ_EEPROM 0xF0
41 #define W1_F23_WRITE_SCRATCH 0x0F
42 #define W1_F23_READ_SCRATCH 0xAA
43 #define W1_F23_COPY_SCRATCH 0x55
44
45 struct w1_f23_data {
46 u8 memory[W1_EEPROM_SIZE];
47 u32 validcrc;
48 };
49
50 /**
51 * Check the file size bounds and adjusts count as needed.
52 * This would not be needed if the file size didn't reset to 0 after a write.
53 */
54 static inline size_t w1_f23_fix_count(loff_t off, size_t count, size_t size)
55 {
56 if (off > size)
57 return 0;
58
59 if ((off + count) > size)
60 return (size - off);
61
62 return count;
63 }
64
65 #ifdef CONFIG_W1_SLAVE_DS2433_CRC
66 static int w1_f23_refresh_block(struct w1_slave *sl, struct w1_f23_data *data,
67 int block)
68 {
69 u8 wrbuf[3];
70 int off = block * W1_PAGE_SIZE;
71
72 if (data->validcrc & (1 << block))
73 return 0;
74
75 if (w1_reset_select_slave(sl)) {
76 data->validcrc = 0;
77 return -EIO;
78 }
79
80 wrbuf[0] = W1_F23_READ_EEPROM;
81 wrbuf[1] = off & 0xff;
82 wrbuf[2] = off >> 8;
83 w1_write_block(sl->master, wrbuf, 3);
84 w1_read_block(sl->master, &data->memory[off], W1_PAGE_SIZE);
85
86 /* cache the block if the CRC is valid */
87 if (crc16(CRC16_INIT, &data->memory[off], W1_PAGE_SIZE) == CRC16_VALID)
88 data->validcrc |= (1 << block);
89
90 return 0;
91 }
92 #endif /* CONFIG_W1_SLAVE_DS2433_CRC */
93
94 static ssize_t w1_f23_read_bin(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 #ifdef CONFIG_W1_SLAVE_DS2433_CRC
100 struct w1_f23_data *data = sl->family_data;
101 int i, min_page, max_page;
102 #else
103 u8 wrbuf[3];
104 #endif
105
106 if ((count = w1_f23_fix_count(off, count, W1_EEPROM_SIZE)) == 0)
107 return 0;
108
109 mutex_lock(&sl->master->mutex);
110
111 #ifdef CONFIG_W1_SLAVE_DS2433_CRC
112
113 min_page = (off >> W1_PAGE_BITS);
114 max_page = (off + count - 1) >> W1_PAGE_BITS;
115 for (i = min_page; i <= max_page; i++) {
116 if (w1_f23_refresh_block(sl, data, i)) {
117 count = -EIO;
118 goto out_up;
119 }
120 }
121 memcpy(buf, &data->memory[off], count);
122
123 #else /* CONFIG_W1_SLAVE_DS2433_CRC */
124
125 /* read directly from the EEPROM */
126 if (w1_reset_select_slave(sl)) {
127 count = -EIO;
128 goto out_up;
129 }
130
131 wrbuf[0] = W1_F23_READ_EEPROM;
132 wrbuf[1] = off & 0xff;
133 wrbuf[2] = off >> 8;
134 w1_write_block(sl->master, wrbuf, 3);
135 w1_read_block(sl->master, buf, count);
136
137 #endif /* CONFIG_W1_SLAVE_DS2433_CRC */
138
139 out_up:
140 mutex_unlock(&sl->master->mutex);
141
142 return count;
143 }
144
145 /**
146 * Writes to the scratchpad and reads it back for verification.
147 * Then copies the scratchpad to EEPROM.
148 * The data must be on one page.
149 * The master must be locked.
150 *
151 * @param sl The slave structure
152 * @param addr Address for the write
153 * @param len length must be <= (W1_PAGE_SIZE - (addr & W1_PAGE_MASK))
154 * @param data The data to write
155 * @return 0=Success -1=failure
156 */
157 static int w1_f23_write(struct w1_slave *sl, int addr, int len, const u8 *data)
158 {
159 u8 wrbuf[4];
160 u8 rdbuf[W1_PAGE_SIZE + 3];
161 u8 es = (addr + len - 1) & 0x1f;
162
163 /* Write the data to the scratchpad */
164 if (w1_reset_select_slave(sl))
165 return -1;
166
167 wrbuf[0] = W1_F23_WRITE_SCRATCH;
168 wrbuf[1] = addr & 0xff;
169 wrbuf[2] = addr >> 8;
170
171 w1_write_block(sl->master, wrbuf, 3);
172 w1_write_block(sl->master, data, len);
173
174 /* Read the scratchpad and verify */
175 if (w1_reset_select_slave(sl))
176 return -1;
177
178 w1_write_8(sl->master, W1_F23_READ_SCRATCH);
179 w1_read_block(sl->master, rdbuf, len + 3);
180
181 /* Compare what was read against the data written */
182 if ((rdbuf[0] != wrbuf[1]) || (rdbuf[1] != wrbuf[2]) ||
183 (rdbuf[2] != es) || (memcmp(data, &rdbuf[3], len) != 0))
184 return -1;
185
186 /* Copy the scratchpad to EEPROM */
187 if (w1_reset_select_slave(sl))
188 return -1;
189
190 wrbuf[0] = W1_F23_COPY_SCRATCH;
191 wrbuf[3] = es;
192 w1_write_block(sl->master, wrbuf, 4);
193
194 /* Sleep for 5 ms to wait for the write to complete */
195 msleep(5);
196
197 /* Reset the bus to wake up the EEPROM (this may not be needed) */
198 w1_reset_bus(sl->master);
199
200 return 0;
201 }
202
203 static ssize_t w1_f23_write_bin(struct kobject *kobj,
204 struct bin_attribute *bin_attr,
205 char *buf, loff_t off, size_t count)
206 {
207 struct w1_slave *sl = kobj_to_w1_slave(kobj);
208 int addr, len, idx;
209
210 if ((count = w1_f23_fix_count(off, count, W1_EEPROM_SIZE)) == 0)
211 return 0;
212
213 #ifdef CONFIG_W1_SLAVE_DS2433_CRC
214 /* can only write full blocks in cached mode */
215 if ((off & W1_PAGE_MASK) || (count & W1_PAGE_MASK)) {
216 dev_err(&sl->dev, "invalid offset/count off=%d cnt=%zd\n",
217 (int)off, count);
218 return -EINVAL;
219 }
220
221 /* make sure the block CRCs are valid */
222 for (idx = 0; idx < count; idx += W1_PAGE_SIZE) {
223 if (crc16(CRC16_INIT, &buf[idx], W1_PAGE_SIZE) != CRC16_VALID) {
224 dev_err(&sl->dev, "bad CRC at offset %d\n", (int)off);
225 return -EINVAL;
226 }
227 }
228 #endif /* CONFIG_W1_SLAVE_DS2433_CRC */
229
230 mutex_lock(&sl->master->mutex);
231
232 /* Can only write data to one page at a time */
233 idx = 0;
234 while (idx < count) {
235 addr = off + idx;
236 len = W1_PAGE_SIZE - (addr & W1_PAGE_MASK);
237 if (len > (count - idx))
238 len = count - idx;
239
240 if (w1_f23_write(sl, addr, len, &buf[idx]) < 0) {
241 count = -EIO;
242 goto out_up;
243 }
244 idx += len;
245 }
246
247 out_up:
248 mutex_unlock(&sl->master->mutex);
249
250 return count;
251 }
252
253 static struct bin_attribute w1_f23_bin_attr = {
254 .attr = {
255 .name = "eeprom",
256 .mode = S_IRUGO | S_IWUSR,
257 },
258 .size = W1_EEPROM_SIZE,
259 .read = w1_f23_read_bin,
260 .write = w1_f23_write_bin,
261 };
262
263 static int w1_f23_add_slave(struct w1_slave *sl)
264 {
265 int err;
266 #ifdef CONFIG_W1_SLAVE_DS2433_CRC
267 struct w1_f23_data *data;
268
269 data = kzalloc(sizeof(struct w1_f23_data), GFP_KERNEL);
270 if (!data)
271 return -ENOMEM;
272 sl->family_data = data;
273
274 #endif /* CONFIG_W1_SLAVE_DS2433_CRC */
275
276 err = sysfs_create_bin_file(&sl->dev.kobj, &w1_f23_bin_attr);
277
278 #ifdef CONFIG_W1_SLAVE_DS2433_CRC
279 if (err)
280 kfree(data);
281 #endif /* CONFIG_W1_SLAVE_DS2433_CRC */
282
283 return err;
284 }
285
286 static void w1_f23_remove_slave(struct w1_slave *sl)
287 {
288 #ifdef CONFIG_W1_SLAVE_DS2433_CRC
289 kfree(sl->family_data);
290 sl->family_data = NULL;
291 #endif /* CONFIG_W1_SLAVE_DS2433_CRC */
292 sysfs_remove_bin_file(&sl->dev.kobj, &w1_f23_bin_attr);
293 }
294
295 static struct w1_family_ops w1_f23_fops = {
296 .add_slave = w1_f23_add_slave,
297 .remove_slave = w1_f23_remove_slave,
298 };
299
300 static struct w1_family w1_family_23 = {
301 .fid = W1_EEPROM_DS2433,
302 .fops = &w1_f23_fops,
303 };
304
305 static int __init w1_f23_init(void)
306 {
307 return w1_register_family(&w1_family_23);
308 }
309
310 static void __exit w1_f23_fini(void)
311 {
312 w1_unregister_family(&w1_family_23);
313 }
314
315 module_init(w1_f23_init);
316 module_exit(w1_f23_fini);
317
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