1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * w1_ds2433.c - w1 family 23 (DS2433) driver
4 *
5 * Copyright (c) 2005 Ben Gardner <bgardner@wabtec.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 #include <linux/slab.h>
15 #ifdef CONFIG_W1_SLAVE_DS2433_CRC
16 #include <linux/crc16.h>
17
18 #define CRC16_INIT 0
19 #define CRC16_VALID 0xb001
20
21 #endif
22
23 #include <linux/w1.h>
24
25 #define W1_EEPROM_DS2433 0x23
26
27 #define W1_EEPROM_SIZE 512
28 #define W1_PAGE_COUNT 16
29 #define W1_PAGE_SIZE 32
30 #define W1_PAGE_BITS 5
31 #define W1_PAGE_MASK 0x1F
32
33 #define W1_F23_TIME 300
34
35 #define W1_F23_READ_EEPROM 0xF0
36 #define W1_F23_WRITE_SCRATCH 0x0F
37 #define W1_F23_READ_SCRATCH 0xAA
38 #define W1_F23_COPY_SCRATCH 0x55
39
40 struct w1_f23_data {
41 u8 memory[W1_EEPROM_SIZE];
42 u32 validcrc;
43 };
44
45 /**
46 * Check the file size bounds and adjusts count as needed.
47 * This would not be needed if the file size didn't reset to 0 after a write.
48 */
w1_f23_fix_count(loff_t off,size_t count,size_t size)49 static inline size_t w1_f23_fix_count(loff_t off, size_t count, size_t size)
50 {
51 if (off > size)
52 return 0;
53
54 if ((off + count) > size)
55 return (size - off);
56
57 return count;
58 }
59
60 #ifdef CONFIG_W1_SLAVE_DS2433_CRC
w1_f23_refresh_block(struct w1_slave * sl,struct w1_f23_data * data,int block)61 static int w1_f23_refresh_block(struct w1_slave *sl, struct w1_f23_data *data,
62 int block)
63 {
64 u8 wrbuf[3];
65 int off = block * W1_PAGE_SIZE;
66
67 if (data->validcrc & (1 << block))
68 return 0;
69
70 if (w1_reset_select_slave(sl)) {
71 data->validcrc = 0;
72 return -EIO;
73 }
74
75 wrbuf[0] = W1_F23_READ_EEPROM;
76 wrbuf[1] = off & 0xff;
77 wrbuf[2] = off >> 8;
78 w1_write_block(sl->master, wrbuf, 3);
79 w1_read_block(sl->master, &data->memory[off], W1_PAGE_SIZE);
80
81 /* cache the block if the CRC is valid */
82 if (crc16(CRC16_INIT, &data->memory[off], W1_PAGE_SIZE) == CRC16_VALID)
83 data->validcrc |= (1 << block);
84
85 return 0;
86 }
87 #endif /* CONFIG_W1_SLAVE_DS2433_CRC */
88
eeprom_read(struct file * filp,struct kobject * kobj,struct bin_attribute * bin_attr,char * buf,loff_t off,size_t count)89 static ssize_t eeprom_read(struct file *filp, struct kobject *kobj,
90 struct bin_attribute *bin_attr, char *buf,
91 loff_t off, size_t count)
92 {
93 struct w1_slave *sl = kobj_to_w1_slave(kobj);
94 #ifdef CONFIG_W1_SLAVE_DS2433_CRC
95 struct w1_f23_data *data = sl->family_data;
96 int i, min_page, max_page;
97 #else
98 u8 wrbuf[3];
99 #endif
100
101 if ((count = w1_f23_fix_count(off, count, W1_EEPROM_SIZE)) == 0)
102 return 0;
103
104 mutex_lock(&sl->master->bus_mutex);
105
106 #ifdef CONFIG_W1_SLAVE_DS2433_CRC
107
108 min_page = (off >> W1_PAGE_BITS);
109 max_page = (off + count - 1) >> W1_PAGE_BITS;
110 for (i = min_page; i <= max_page; i++) {
111 if (w1_f23_refresh_block(sl, data, i)) {
112 count = -EIO;
113 goto out_up;
114 }
115 }
116 memcpy(buf, &data->memory[off], count);
117
118 #else /* CONFIG_W1_SLAVE_DS2433_CRC */
119
120 /* read directly from the EEPROM */
121 if (w1_reset_select_slave(sl)) {
122 count = -EIO;
123 goto out_up;
124 }
125
126 wrbuf[0] = W1_F23_READ_EEPROM;
127 wrbuf[1] = off & 0xff;
128 wrbuf[2] = off >> 8;
129 w1_write_block(sl->master, wrbuf, 3);
130 w1_read_block(sl->master, buf, count);
131
132 #endif /* CONFIG_W1_SLAVE_DS2433_CRC */
133
134 out_up:
135 mutex_unlock(&sl->master->bus_mutex);
136
137 return count;
138 }
139
140 /**
141 * Writes to the scratchpad and reads it back for verification.
142 * Then copies the scratchpad to EEPROM.
143 * The data must be on one page.
144 * The master must be locked.
145 *
146 * @param sl The slave structure
147 * @param addr Address for the write
148 * @param len length must be <= (W1_PAGE_SIZE - (addr & W1_PAGE_MASK))
149 * @param data The data to write
150 * @return 0=Success -1=failure
151 */
w1_f23_write(struct w1_slave * sl,int addr,int len,const u8 * data)152 static int w1_f23_write(struct w1_slave *sl, int addr, int len, const u8 *data)
153 {
154 #ifdef CONFIG_W1_SLAVE_DS2433_CRC
155 struct w1_f23_data *f23 = sl->family_data;
156 #endif
157 u8 wrbuf[4];
158 u8 rdbuf[W1_PAGE_SIZE + 3];
159 u8 es = (addr + len - 1) & 0x1f;
160
161 /* Write the data to the scratchpad */
162 if (w1_reset_select_slave(sl))
163 return -1;
164
165 wrbuf[0] = W1_F23_WRITE_SCRATCH;
166 wrbuf[1] = addr & 0xff;
167 wrbuf[2] = addr >> 8;
168
169 w1_write_block(sl->master, wrbuf, 3);
170 w1_write_block(sl->master, data, len);
171
172 /* Read the scratchpad and verify */
173 if (w1_reset_select_slave(sl))
174 return -1;
175
176 w1_write_8(sl->master, W1_F23_READ_SCRATCH);
177 w1_read_block(sl->master, rdbuf, len + 3);
178
179 /* Compare what was read against the data written */
180 if ((rdbuf[0] != wrbuf[1]) || (rdbuf[1] != wrbuf[2]) ||
181 (rdbuf[2] != es) || (memcmp(data, &rdbuf[3], len) != 0))
182 return -1;
183
184 /* Copy the scratchpad to EEPROM */
185 if (w1_reset_select_slave(sl))
186 return -1;
187
188 wrbuf[0] = W1_F23_COPY_SCRATCH;
189 wrbuf[3] = es;
190 w1_write_block(sl->master, wrbuf, 4);
191
192 /* Sleep for 5 ms to wait for the write to complete */
193 msleep(5);
194
195 /* Reset the bus to wake up the EEPROM (this may not be needed) */
196 w1_reset_bus(sl->master);
197 #ifdef CONFIG_W1_SLAVE_DS2433_CRC
198 f23->validcrc &= ~(1 << (addr >> W1_PAGE_BITS));
199 #endif
200 return 0;
201 }
202
eeprom_write(struct file * filp,struct kobject * kobj,struct bin_attribute * bin_attr,char * buf,loff_t off,size_t count)203 static ssize_t eeprom_write(struct file *filp, struct kobject *kobj,
204 struct bin_attribute *bin_attr, char *buf,
205 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->bus_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->bus_mutex);
249
250 return count;
251 }
252
253 static BIN_ATTR_RW(eeprom, W1_EEPROM_SIZE);
254
255 static struct bin_attribute *w1_f23_bin_attributes[] = {
256 &bin_attr_eeprom,
257 NULL,
258 };
259
260 static const struct attribute_group w1_f23_group = {
261 .bin_attrs = w1_f23_bin_attributes,
262 };
263
264 static const struct attribute_group *w1_f23_groups[] = {
265 &w1_f23_group,
266 NULL,
267 };
268
w1_f23_add_slave(struct w1_slave * sl)269 static int w1_f23_add_slave(struct w1_slave *sl)
270 {
271 #ifdef CONFIG_W1_SLAVE_DS2433_CRC
272 struct w1_f23_data *data;
273
274 data = kzalloc(sizeof(struct w1_f23_data), GFP_KERNEL);
275 if (!data)
276 return -ENOMEM;
277 sl->family_data = data;
278
279 #endif /* CONFIG_W1_SLAVE_DS2433_CRC */
280 return 0;
281 }
282
w1_f23_remove_slave(struct w1_slave * sl)283 static void w1_f23_remove_slave(struct w1_slave *sl)
284 {
285 #ifdef CONFIG_W1_SLAVE_DS2433_CRC
286 kfree(sl->family_data);
287 sl->family_data = NULL;
288 #endif /* CONFIG_W1_SLAVE_DS2433_CRC */
289 }
290
291 static const struct w1_family_ops w1_f23_fops = {
292 .add_slave = w1_f23_add_slave,
293 .remove_slave = w1_f23_remove_slave,
294 .groups = w1_f23_groups,
295 };
296
297 static struct w1_family w1_family_23 = {
298 .fid = W1_EEPROM_DS2433,
299 .fops = &w1_f23_fops,
300 };
301 module_w1_family(w1_family_23);
302
303 MODULE_AUTHOR("Ben Gardner <bgardner@wabtec.com>");
304 MODULE_DESCRIPTION("w1 family 23 driver for DS2433, 4kb EEPROM");
305 MODULE_LICENSE("GPL");
306 MODULE_ALIAS("w1-family-" __stringify(W1_EEPROM_DS2433));
307