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 #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
29 MODULE_LICENSE("GPL");
30 MODULE_AUTHOR("Ben Gardner <bgardner@wabtec.com>");
31 MODULE_DESCRIPTION("w1 family 23 driver for DS2433, 4kb EEPROM");
32
33 #define W1_EEPROM_SIZE 512
34 #define W1_PAGE_COUNT 16
35 #define W1_PAGE_SIZE 32
36 #define W1_PAGE_BITS 5
37 #define W1_PAGE_MASK 0x1F
38
39 #define W1_F23_TIME 300
40
41 #define W1_F23_READ_EEPROM 0xF0
42 #define W1_F23_WRITE_SCRATCH 0x0F
43 #define W1_F23_READ_SCRATCH 0xAA
44 #define W1_F23_COPY_SCRATCH 0x55
45
46 struct w1_f23_data {
47 u8 memory[W1_EEPROM_SIZE];
48 u32 validcrc;
49 };
50
51 /**
52 * Check the file size bounds and adjusts count as needed.
53 * This would not be needed if the file size didn't reset to 0 after a write.
54 */
w1_f23_fix_count(loff_t off,size_t count,size_t size)55 static inline size_t w1_f23_fix_count(loff_t off, size_t count, size_t size)
56 {
57 if (off > size)
58 return 0;
59
60 if ((off + count) > size)
61 return (size - off);
62
63 return count;
64 }
65
66 #ifdef CONFIG_W1_SLAVE_DS2433_CRC
w1_f23_refresh_block(struct w1_slave * sl,struct w1_f23_data * data,int block)67 static int w1_f23_refresh_block(struct w1_slave *sl, struct w1_f23_data *data,
68 int block)
69 {
70 u8 wrbuf[3];
71 int off = block * W1_PAGE_SIZE;
72
73 if (data->validcrc & (1 << block))
74 return 0;
75
76 if (w1_reset_select_slave(sl)) {
77 data->validcrc = 0;
78 return -EIO;
79 }
80
81 wrbuf[0] = W1_F23_READ_EEPROM;
82 wrbuf[1] = off & 0xff;
83 wrbuf[2] = off >> 8;
84 w1_write_block(sl->master, wrbuf, 3);
85 w1_read_block(sl->master, &data->memory[off], W1_PAGE_SIZE);
86
87 /* cache the block if the CRC is valid */
88 if (crc16(CRC16_INIT, &data->memory[off], W1_PAGE_SIZE) == CRC16_VALID)
89 data->validcrc |= (1 << block);
90
91 return 0;
92 }
93 #endif /* CONFIG_W1_SLAVE_DS2433_CRC */
94
w1_f23_read_bin(struct file * filp,struct kobject * kobj,struct bin_attribute * bin_attr,char * buf,loff_t off,size_t count)95 static ssize_t w1_f23_read_bin(struct file *filp, struct kobject *kobj,
96 struct bin_attribute *bin_attr,
97 char *buf, loff_t off, size_t count)
98 {
99 struct w1_slave *sl = kobj_to_w1_slave(kobj);
100 #ifdef CONFIG_W1_SLAVE_DS2433_CRC
101 struct w1_f23_data *data = sl->family_data;
102 int i, min_page, max_page;
103 #else
104 u8 wrbuf[3];
105 #endif
106
107 if ((count = w1_f23_fix_count(off, count, W1_EEPROM_SIZE)) == 0)
108 return 0;
109
110 mutex_lock(&sl->master->mutex);
111
112 #ifdef CONFIG_W1_SLAVE_DS2433_CRC
113
114 min_page = (off >> W1_PAGE_BITS);
115 max_page = (off + count - 1) >> W1_PAGE_BITS;
116 for (i = min_page; i <= max_page; i++) {
117 if (w1_f23_refresh_block(sl, data, i)) {
118 count = -EIO;
119 goto out_up;
120 }
121 }
122 memcpy(buf, &data->memory[off], count);
123
124 #else /* CONFIG_W1_SLAVE_DS2433_CRC */
125
126 /* read directly from the EEPROM */
127 if (w1_reset_select_slave(sl)) {
128 count = -EIO;
129 goto out_up;
130 }
131
132 wrbuf[0] = W1_F23_READ_EEPROM;
133 wrbuf[1] = off & 0xff;
134 wrbuf[2] = off >> 8;
135 w1_write_block(sl->master, wrbuf, 3);
136 w1_read_block(sl->master, buf, count);
137
138 #endif /* CONFIG_W1_SLAVE_DS2433_CRC */
139
140 out_up:
141 mutex_unlock(&sl->master->mutex);
142
143 return count;
144 }
145
146 /**
147 * Writes to the scratchpad and reads it back for verification.
148 * Then copies the scratchpad to EEPROM.
149 * The data must be on one page.
150 * The master must be locked.
151 *
152 * @param sl The slave structure
153 * @param addr Address for the write
154 * @param len length must be <= (W1_PAGE_SIZE - (addr & W1_PAGE_MASK))
155 * @param data The data to write
156 * @return 0=Success -1=failure
157 */
w1_f23_write(struct w1_slave * sl,int addr,int len,const u8 * data)158 static int w1_f23_write(struct w1_slave *sl, int addr, int len, const u8 *data)
159 {
160 #ifdef CONFIG_W1_SLAVE_DS2433_CRC
161 struct w1_f23_data *f23 = sl->family_data;
162 #endif
163 u8 wrbuf[4];
164 u8 rdbuf[W1_PAGE_SIZE + 3];
165 u8 es = (addr + len - 1) & 0x1f;
166
167 /* Write the data to the scratchpad */
168 if (w1_reset_select_slave(sl))
169 return -1;
170
171 wrbuf[0] = W1_F23_WRITE_SCRATCH;
172 wrbuf[1] = addr & 0xff;
173 wrbuf[2] = addr >> 8;
174
175 w1_write_block(sl->master, wrbuf, 3);
176 w1_write_block(sl->master, data, len);
177
178 /* Read the scratchpad and verify */
179 if (w1_reset_select_slave(sl))
180 return -1;
181
182 w1_write_8(sl->master, W1_F23_READ_SCRATCH);
183 w1_read_block(sl->master, rdbuf, len + 3);
184
185 /* Compare what was read against the data written */
186 if ((rdbuf[0] != wrbuf[1]) || (rdbuf[1] != wrbuf[2]) ||
187 (rdbuf[2] != es) || (memcmp(data, &rdbuf[3], len) != 0))
188 return -1;
189
190 /* Copy the scratchpad to EEPROM */
191 if (w1_reset_select_slave(sl))
192 return -1;
193
194 wrbuf[0] = W1_F23_COPY_SCRATCH;
195 wrbuf[3] = es;
196 w1_write_block(sl->master, wrbuf, 4);
197
198 /* Sleep for 5 ms to wait for the write to complete */
199 msleep(5);
200
201 /* Reset the bus to wake up the EEPROM (this may not be needed) */
202 w1_reset_bus(sl->master);
203 #ifdef CONFIG_W1_SLAVE_DS2433_CRC
204 f23->validcrc &= ~(1 << (addr >> W1_PAGE_BITS));
205 #endif
206 return 0;
207 }
208
w1_f23_write_bin(struct file * filp,struct kobject * kobj,struct bin_attribute * bin_attr,char * buf,loff_t off,size_t count)209 static ssize_t w1_f23_write_bin(struct file *filp, struct kobject *kobj,
210 struct bin_attribute *bin_attr,
211 char *buf, loff_t off, size_t count)
212 {
213 struct w1_slave *sl = kobj_to_w1_slave(kobj);
214 int addr, len, idx;
215
216 if ((count = w1_f23_fix_count(off, count, W1_EEPROM_SIZE)) == 0)
217 return 0;
218
219 #ifdef CONFIG_W1_SLAVE_DS2433_CRC
220 /* can only write full blocks in cached mode */
221 if ((off & W1_PAGE_MASK) || (count & W1_PAGE_MASK)) {
222 dev_err(&sl->dev, "invalid offset/count off=%d cnt=%zd\n",
223 (int)off, count);
224 return -EINVAL;
225 }
226
227 /* make sure the block CRCs are valid */
228 for (idx = 0; idx < count; idx += W1_PAGE_SIZE) {
229 if (crc16(CRC16_INIT, &buf[idx], W1_PAGE_SIZE) != CRC16_VALID) {
230 dev_err(&sl->dev, "bad CRC at offset %d\n", (int)off);
231 return -EINVAL;
232 }
233 }
234 #endif /* CONFIG_W1_SLAVE_DS2433_CRC */
235
236 mutex_lock(&sl->master->mutex);
237
238 /* Can only write data to one page at a time */
239 idx = 0;
240 while (idx < count) {
241 addr = off + idx;
242 len = W1_PAGE_SIZE - (addr & W1_PAGE_MASK);
243 if (len > (count - idx))
244 len = count - idx;
245
246 if (w1_f23_write(sl, addr, len, &buf[idx]) < 0) {
247 count = -EIO;
248 goto out_up;
249 }
250 idx += len;
251 }
252
253 out_up:
254 mutex_unlock(&sl->master->mutex);
255
256 return count;
257 }
258
259 static struct bin_attribute w1_f23_bin_attr = {
260 .attr = {
261 .name = "eeprom",
262 .mode = S_IRUGO | S_IWUSR,
263 },
264 .size = W1_EEPROM_SIZE,
265 .read = w1_f23_read_bin,
266 .write = w1_f23_write_bin,
267 };
268
w1_f23_add_slave(struct w1_slave * sl)269 static int w1_f23_add_slave(struct w1_slave *sl)
270 {
271 int err;
272 #ifdef CONFIG_W1_SLAVE_DS2433_CRC
273 struct w1_f23_data *data;
274
275 data = kzalloc(sizeof(struct w1_f23_data), GFP_KERNEL);
276 if (!data)
277 return -ENOMEM;
278 sl->family_data = data;
279
280 #endif /* CONFIG_W1_SLAVE_DS2433_CRC */
281
282 err = sysfs_create_bin_file(&sl->dev.kobj, &w1_f23_bin_attr);
283
284 #ifdef CONFIG_W1_SLAVE_DS2433_CRC
285 if (err)
286 kfree(data);
287 #endif /* CONFIG_W1_SLAVE_DS2433_CRC */
288
289 return err;
290 }
291
w1_f23_remove_slave(struct w1_slave * sl)292 static void w1_f23_remove_slave(struct w1_slave *sl)
293 {
294 #ifdef CONFIG_W1_SLAVE_DS2433_CRC
295 kfree(sl->family_data);
296 sl->family_data = NULL;
297 #endif /* CONFIG_W1_SLAVE_DS2433_CRC */
298 sysfs_remove_bin_file(&sl->dev.kobj, &w1_f23_bin_attr);
299 }
300
301 static struct w1_family_ops w1_f23_fops = {
302 .add_slave = w1_f23_add_slave,
303 .remove_slave = w1_f23_remove_slave,
304 };
305
306 static struct w1_family w1_family_23 = {
307 .fid = W1_EEPROM_DS2433,
308 .fops = &w1_f23_fops,
309 };
310
w1_f23_init(void)311 static int __init w1_f23_init(void)
312 {
313 return w1_register_family(&w1_family_23);
314 }
315
w1_f23_fini(void)316 static void __exit w1_f23_fini(void)
317 {
318 w1_unregister_family(&w1_family_23);
319 }
320
321 module_init(w1_f23_init);
322 module_exit(w1_f23_fini);
323