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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#ifdef CONFIG_W1_SLAVE_DS2433_CRC
18#include <linux/crc16.h>
19
20#define CRC16_INIT 0
21#define CRC16_VALID 0xb001
22
23#endif
24
25#include "../w1.h"
26#include "../w1_int.h"
27#include "../w1_family.h"
28
29MODULE_LICENSE("GPL");
30MODULE_AUTHOR("Ben Gardner <bgardner@wabtec.com>");
31MODULE_DESCRIPTION("w1 family 23 driver for DS2433, 4kb EEPROM");
32MODULE_ALIAS("w1-family-" __stringify(W1_EEPROM_DS2433));
33
34#define W1_EEPROM_SIZE 512
35#define W1_PAGE_COUNT 16
36#define W1_PAGE_SIZE 32
37#define W1_PAGE_BITS 5
38#define W1_PAGE_MASK 0x1F
39
40#define W1_F23_TIME 300
41
42#define W1_F23_READ_EEPROM 0xF0
43#define W1_F23_WRITE_SCRATCH 0x0F
44#define W1_F23_READ_SCRATCH 0xAA
45#define W1_F23_COPY_SCRATCH 0x55
46
47struct w1_f23_data {
48 u8 memory[W1_EEPROM_SIZE];
49 u32 validcrc;
50};
51
52
53
54
55
56static inline size_t w1_f23_fix_count(loff_t off, size_t count, size_t size)
57{
58 if (off > size)
59 return 0;
60
61 if ((off + count) > size)
62 return (size - off);
63
64 return count;
65}
66
67#ifdef CONFIG_W1_SLAVE_DS2433_CRC
68static int w1_f23_refresh_block(struct w1_slave *sl, struct w1_f23_data *data,
69 int block)
70{
71 u8 wrbuf[3];
72 int off = block * W1_PAGE_SIZE;
73
74 if (data->validcrc & (1 << block))
75 return 0;
76
77 if (w1_reset_select_slave(sl)) {
78 data->validcrc = 0;
79 return -EIO;
80 }
81
82 wrbuf[0] = W1_F23_READ_EEPROM;
83 wrbuf[1] = off & 0xff;
84 wrbuf[2] = off >> 8;
85 w1_write_block(sl->master, wrbuf, 3);
86 w1_read_block(sl->master, &data->memory[off], W1_PAGE_SIZE);
87
88
89 if (crc16(CRC16_INIT, &data->memory[off], W1_PAGE_SIZE) == CRC16_VALID)
90 data->validcrc |= (1 << block);
91
92 return 0;
93}
94#endif
95
96static ssize_t eeprom_read(struct file *filp, struct kobject *kobj,
97 struct bin_attribute *bin_attr, char *buf,
98 loff_t off, size_t count)
99{
100 struct w1_slave *sl = kobj_to_w1_slave(kobj);
101#ifdef CONFIG_W1_SLAVE_DS2433_CRC
102 struct w1_f23_data *data = sl->family_data;
103 int i, min_page, max_page;
104#else
105 u8 wrbuf[3];
106#endif
107
108 if ((count = w1_f23_fix_count(off, count, W1_EEPROM_SIZE)) == 0)
109 return 0;
110
111 mutex_lock(&sl->master->bus_mutex);
112
113#ifdef CONFIG_W1_SLAVE_DS2433_CRC
114
115 min_page = (off >> W1_PAGE_BITS);
116 max_page = (off + count - 1) >> W1_PAGE_BITS;
117 for (i = min_page; i <= max_page; i++) {
118 if (w1_f23_refresh_block(sl, data, i)) {
119 count = -EIO;
120 goto out_up;
121 }
122 }
123 memcpy(buf, &data->memory[off], count);
124
125#else
126
127
128 if (w1_reset_select_slave(sl)) {
129 count = -EIO;
130 goto out_up;
131 }
132
133 wrbuf[0] = W1_F23_READ_EEPROM;
134 wrbuf[1] = off & 0xff;
135 wrbuf[2] = off >> 8;
136 w1_write_block(sl->master, wrbuf, 3);
137 w1_read_block(sl->master, buf, count);
138
139#endif
140
141out_up:
142 mutex_unlock(&sl->master->bus_mutex);
143
144 return count;
145}
146
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153
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156
157
158
159static int w1_f23_write(struct w1_slave *sl, int addr, int len, const u8 *data)
160{
161#ifdef CONFIG_W1_SLAVE_DS2433_CRC
162 struct w1_f23_data *f23 = sl->family_data;
163#endif
164 u8 wrbuf[4];
165 u8 rdbuf[W1_PAGE_SIZE + 3];
166 u8 es = (addr + len - 1) & 0x1f;
167
168
169 if (w1_reset_select_slave(sl))
170 return -1;
171
172 wrbuf[0] = W1_F23_WRITE_SCRATCH;
173 wrbuf[1] = addr & 0xff;
174 wrbuf[2] = addr >> 8;
175
176 w1_write_block(sl->master, wrbuf, 3);
177 w1_write_block(sl->master, data, len);
178
179
180 if (w1_reset_select_slave(sl))
181 return -1;
182
183 w1_write_8(sl->master, W1_F23_READ_SCRATCH);
184 w1_read_block(sl->master, rdbuf, len + 3);
185
186
187 if ((rdbuf[0] != wrbuf[1]) || (rdbuf[1] != wrbuf[2]) ||
188 (rdbuf[2] != es) || (memcmp(data, &rdbuf[3], len) != 0))
189 return -1;
190
191
192 if (w1_reset_select_slave(sl))
193 return -1;
194
195 wrbuf[0] = W1_F23_COPY_SCRATCH;
196 wrbuf[3] = es;
197 w1_write_block(sl->master, wrbuf, 4);
198
199
200 msleep(5);
201
202
203 w1_reset_bus(sl->master);
204#ifdef CONFIG_W1_SLAVE_DS2433_CRC
205 f23->validcrc &= ~(1 << (addr >> W1_PAGE_BITS));
206#endif
207 return 0;
208}
209
210static ssize_t eeprom_write(struct file *filp, struct kobject *kobj,
211 struct bin_attribute *bin_attr, char *buf,
212 loff_t off, size_t count)
213{
214 struct w1_slave *sl = kobj_to_w1_slave(kobj);
215 int addr, len, idx;
216
217 if ((count = w1_f23_fix_count(off, count, W1_EEPROM_SIZE)) == 0)
218 return 0;
219
220#ifdef CONFIG_W1_SLAVE_DS2433_CRC
221
222 if ((off & W1_PAGE_MASK) || (count & W1_PAGE_MASK)) {
223 dev_err(&sl->dev, "invalid offset/count off=%d cnt=%zd\n",
224 (int)off, count);
225 return -EINVAL;
226 }
227
228
229 for (idx = 0; idx < count; idx += W1_PAGE_SIZE) {
230 if (crc16(CRC16_INIT, &buf[idx], W1_PAGE_SIZE) != CRC16_VALID) {
231 dev_err(&sl->dev, "bad CRC at offset %d\n", (int)off);
232 return -EINVAL;
233 }
234 }
235#endif
236
237 mutex_lock(&sl->master->bus_mutex);
238
239
240 idx = 0;
241 while (idx < count) {
242 addr = off + idx;
243 len = W1_PAGE_SIZE - (addr & W1_PAGE_MASK);
244 if (len > (count - idx))
245 len = count - idx;
246
247 if (w1_f23_write(sl, addr, len, &buf[idx]) < 0) {
248 count = -EIO;
249 goto out_up;
250 }
251 idx += len;
252 }
253
254out_up:
255 mutex_unlock(&sl->master->bus_mutex);
256
257 return count;
258}
259
260static BIN_ATTR_RW(eeprom, W1_EEPROM_SIZE);
261
262static struct bin_attribute *w1_f23_bin_attributes[] = {
263 &bin_attr_eeprom,
264 NULL,
265};
266
267static const struct attribute_group w1_f23_group = {
268 .bin_attrs = w1_f23_bin_attributes,
269};
270
271static const struct attribute_group *w1_f23_groups[] = {
272 &w1_f23_group,
273 NULL,
274};
275
276static int w1_f23_add_slave(struct w1_slave *sl)
277{
278#ifdef CONFIG_W1_SLAVE_DS2433_CRC
279 struct w1_f23_data *data;
280
281 data = kzalloc(sizeof(struct w1_f23_data), GFP_KERNEL);
282 if (!data)
283 return -ENOMEM;
284 sl->family_data = data;
285
286#endif
287 return 0;
288}
289
290static void w1_f23_remove_slave(struct w1_slave *sl)
291{
292#ifdef CONFIG_W1_SLAVE_DS2433_CRC
293 kfree(sl->family_data);
294 sl->family_data = NULL;
295#endif
296}
297
298static struct w1_family_ops w1_f23_fops = {
299 .add_slave = w1_f23_add_slave,
300 .remove_slave = w1_f23_remove_slave,
301 .groups = w1_f23_groups,
302};
303
304static struct w1_family w1_family_23 = {
305 .fid = W1_EEPROM_DS2433,
306 .fops = &w1_f23_fops,
307};
308
309static int __init w1_f23_init(void)
310{
311 return w1_register_family(&w1_family_23);
312}
313
314static void __exit w1_f23_fini(void)
315{
316 w1_unregister_family(&w1_family_23);
317}
318
319module_init(w1_f23_init);
320module_exit(w1_f23_fini);
321