1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * w1_ds28e04.c - w1 family 1C (DS28E04) driver
4 *
5 * Copyright (c) 2012 Markus Franke <franke.m@sebakmt.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 #include <linux/crc16.h>
16 #include <linux/uaccess.h>
17
18 #define CRC16_INIT 0
19 #define CRC16_VALID 0xb001
20
21 #include <linux/w1.h>
22
23 #define W1_FAMILY_DS28E04 0x1C
24
25 /* Allow the strong pullup to be disabled, but default to enabled.
26 * If it was disabled a parasite powered device might not get the required
27 * current to copy the data from the scratchpad to EEPROM. If it is enabled
28 * parasite powered devices have a better chance of getting the current
29 * required.
30 */
31 static int w1_strong_pullup = 1;
32 module_param_named(strong_pullup, w1_strong_pullup, int, 0);
33
34 /* enable/disable CRC checking on DS28E04-100 memory accesses */
35 static bool w1_enable_crccheck = true;
36
37 #define W1_EEPROM_SIZE 512
38 #define W1_PAGE_COUNT 16
39 #define W1_PAGE_SIZE 32
40 #define W1_PAGE_BITS 5
41 #define W1_PAGE_MASK 0x1F
42
43 #define W1_F1C_READ_EEPROM 0xF0
44 #define W1_F1C_WRITE_SCRATCH 0x0F
45 #define W1_F1C_READ_SCRATCH 0xAA
46 #define W1_F1C_COPY_SCRATCH 0x55
47 #define W1_F1C_ACCESS_WRITE 0x5A
48
49 #define W1_1C_REG_LOGIC_STATE 0x220
50
51 struct w1_f1C_data {
52 u8 memory[W1_EEPROM_SIZE];
53 u32 validcrc;
54 };
55
56 /**
57 * Check the file size bounds and adjusts count as needed.
58 * This would not be needed if the file size didn't reset to 0 after a write.
59 */
w1_f1C_fix_count(loff_t off,size_t count,size_t size)60 static inline size_t w1_f1C_fix_count(loff_t off, size_t count, size_t size)
61 {
62 if (off > size)
63 return 0;
64
65 if ((off + count) > size)
66 return size - off;
67
68 return count;
69 }
70
w1_f1C_refresh_block(struct w1_slave * sl,struct w1_f1C_data * data,int block)71 static int w1_f1C_refresh_block(struct w1_slave *sl, struct w1_f1C_data *data,
72 int block)
73 {
74 u8 wrbuf[3];
75 int off = block * W1_PAGE_SIZE;
76
77 if (data->validcrc & (1 << block))
78 return 0;
79
80 if (w1_reset_select_slave(sl)) {
81 data->validcrc = 0;
82 return -EIO;
83 }
84
85 wrbuf[0] = W1_F1C_READ_EEPROM;
86 wrbuf[1] = off & 0xff;
87 wrbuf[2] = off >> 8;
88 w1_write_block(sl->master, wrbuf, 3);
89 w1_read_block(sl->master, &data->memory[off], W1_PAGE_SIZE);
90
91 /* cache the block if the CRC is valid */
92 if (crc16(CRC16_INIT, &data->memory[off], W1_PAGE_SIZE) == CRC16_VALID)
93 data->validcrc |= (1 << block);
94
95 return 0;
96 }
97
w1_f1C_read(struct w1_slave * sl,int addr,int len,char * data)98 static int w1_f1C_read(struct w1_slave *sl, int addr, int len, char *data)
99 {
100 u8 wrbuf[3];
101
102 /* read directly from the EEPROM */
103 if (w1_reset_select_slave(sl))
104 return -EIO;
105
106 wrbuf[0] = W1_F1C_READ_EEPROM;
107 wrbuf[1] = addr & 0xff;
108 wrbuf[2] = addr >> 8;
109
110 w1_write_block(sl->master, wrbuf, sizeof(wrbuf));
111 return w1_read_block(sl->master, data, len);
112 }
113
eeprom_read(struct file * filp,struct kobject * kobj,struct bin_attribute * bin_attr,char * buf,loff_t off,size_t count)114 static ssize_t eeprom_read(struct file *filp, struct kobject *kobj,
115 struct bin_attribute *bin_attr, char *buf,
116 loff_t off, size_t count)
117 {
118 struct w1_slave *sl = kobj_to_w1_slave(kobj);
119 struct w1_f1C_data *data = sl->family_data;
120 int i, min_page, max_page;
121
122 count = w1_f1C_fix_count(off, count, W1_EEPROM_SIZE);
123 if (count == 0)
124 return 0;
125
126 mutex_lock(&sl->master->mutex);
127
128 if (w1_enable_crccheck) {
129 min_page = (off >> W1_PAGE_BITS);
130 max_page = (off + count - 1) >> W1_PAGE_BITS;
131 for (i = min_page; i <= max_page; i++) {
132 if (w1_f1C_refresh_block(sl, data, i)) {
133 count = -EIO;
134 goto out_up;
135 }
136 }
137 memcpy(buf, &data->memory[off], count);
138 } else {
139 count = w1_f1C_read(sl, off, count, buf);
140 }
141
142 out_up:
143 mutex_unlock(&sl->master->mutex);
144
145 return count;
146 }
147
148 /**
149 * Writes to the scratchpad and reads it back for verification.
150 * Then copies the scratchpad to EEPROM.
151 * The data must be on one page.
152 * The master must be locked.
153 *
154 * @param sl The slave structure
155 * @param addr Address for the write
156 * @param len length must be <= (W1_PAGE_SIZE - (addr & W1_PAGE_MASK))
157 * @param data The data to write
158 * @return 0=Success -1=failure
159 */
w1_f1C_write(struct w1_slave * sl,int addr,int len,const u8 * data)160 static int w1_f1C_write(struct w1_slave *sl, int addr, int len, const u8 *data)
161 {
162 u8 wrbuf[4];
163 u8 rdbuf[W1_PAGE_SIZE + 3];
164 u8 es = (addr + len - 1) & 0x1f;
165 unsigned int tm = 10;
166 int i;
167 struct w1_f1C_data *f1C = sl->family_data;
168
169 /* Write the data to the scratchpad */
170 if (w1_reset_select_slave(sl))
171 return -1;
172
173 wrbuf[0] = W1_F1C_WRITE_SCRATCH;
174 wrbuf[1] = addr & 0xff;
175 wrbuf[2] = addr >> 8;
176
177 w1_write_block(sl->master, wrbuf, 3);
178 w1_write_block(sl->master, data, len);
179
180 /* Read the scratchpad and verify */
181 if (w1_reset_select_slave(sl))
182 return -1;
183
184 w1_write_8(sl->master, W1_F1C_READ_SCRATCH);
185 w1_read_block(sl->master, rdbuf, len + 3);
186
187 /* Compare what was read against the data written */
188 if ((rdbuf[0] != wrbuf[1]) || (rdbuf[1] != wrbuf[2]) ||
189 (rdbuf[2] != es) || (memcmp(data, &rdbuf[3], len) != 0))
190 return -1;
191
192 /* Copy the scratchpad to EEPROM */
193 if (w1_reset_select_slave(sl))
194 return -1;
195
196 wrbuf[0] = W1_F1C_COPY_SCRATCH;
197 wrbuf[3] = es;
198
199 for (i = 0; i < sizeof(wrbuf); ++i) {
200 /* issue 10ms strong pullup (or delay) on the last byte
201 for writing the data from the scratchpad to EEPROM */
202 if (w1_strong_pullup && i == sizeof(wrbuf)-1)
203 w1_next_pullup(sl->master, tm);
204
205 w1_write_8(sl->master, wrbuf[i]);
206 }
207
208 if (!w1_strong_pullup)
209 msleep(tm);
210
211 if (w1_enable_crccheck) {
212 /* invalidate cached data */
213 f1C->validcrc &= ~(1 << (addr >> W1_PAGE_BITS));
214 }
215
216 /* Reset the bus to wake up the EEPROM (this may not be needed) */
217 w1_reset_bus(sl->master);
218
219 return 0;
220 }
221
eeprom_write(struct file * filp,struct kobject * kobj,struct bin_attribute * bin_attr,char * buf,loff_t off,size_t count)222 static ssize_t eeprom_write(struct file *filp, struct kobject *kobj,
223 struct bin_attribute *bin_attr, char *buf,
224 loff_t off, size_t count)
225
226 {
227 struct w1_slave *sl = kobj_to_w1_slave(kobj);
228 int addr, len, idx;
229
230 count = w1_f1C_fix_count(off, count, W1_EEPROM_SIZE);
231 if (count == 0)
232 return 0;
233
234 if (w1_enable_crccheck) {
235 /* can only write full blocks in cached mode */
236 if ((off & W1_PAGE_MASK) || (count & W1_PAGE_MASK)) {
237 dev_err(&sl->dev, "invalid offset/count off=%d cnt=%zd\n",
238 (int)off, count);
239 return -EINVAL;
240 }
241
242 /* make sure the block CRCs are valid */
243 for (idx = 0; idx < count; idx += W1_PAGE_SIZE) {
244 if (crc16(CRC16_INIT, &buf[idx], W1_PAGE_SIZE)
245 != CRC16_VALID) {
246 dev_err(&sl->dev, "bad CRC at offset %d\n",
247 (int)off);
248 return -EINVAL;
249 }
250 }
251 }
252
253 mutex_lock(&sl->master->mutex);
254
255 /* Can only write data to one page at a time */
256 idx = 0;
257 while (idx < count) {
258 addr = off + idx;
259 len = W1_PAGE_SIZE - (addr & W1_PAGE_MASK);
260 if (len > (count - idx))
261 len = count - idx;
262
263 if (w1_f1C_write(sl, addr, len, &buf[idx]) < 0) {
264 count = -EIO;
265 goto out_up;
266 }
267 idx += len;
268 }
269
270 out_up:
271 mutex_unlock(&sl->master->mutex);
272
273 return count;
274 }
275
276 static BIN_ATTR_RW(eeprom, W1_EEPROM_SIZE);
277
pio_read(struct file * filp,struct kobject * kobj,struct bin_attribute * bin_attr,char * buf,loff_t off,size_t count)278 static ssize_t pio_read(struct file *filp, struct kobject *kobj,
279 struct bin_attribute *bin_attr, char *buf, loff_t off,
280 size_t count)
281
282 {
283 struct w1_slave *sl = kobj_to_w1_slave(kobj);
284 int ret;
285
286 /* check arguments */
287 if (off != 0 || count != 1 || buf == NULL)
288 return -EINVAL;
289
290 mutex_lock(&sl->master->mutex);
291 ret = w1_f1C_read(sl, W1_1C_REG_LOGIC_STATE, count, buf);
292 mutex_unlock(&sl->master->mutex);
293
294 return ret;
295 }
296
pio_write(struct file * filp,struct kobject * kobj,struct bin_attribute * bin_attr,char * buf,loff_t off,size_t count)297 static ssize_t pio_write(struct file *filp, struct kobject *kobj,
298 struct bin_attribute *bin_attr, char *buf, loff_t off,
299 size_t count)
300
301 {
302 struct w1_slave *sl = kobj_to_w1_slave(kobj);
303 u8 wrbuf[3];
304 u8 ack;
305
306 /* check arguments */
307 if (off != 0 || count != 1 || buf == NULL)
308 return -EINVAL;
309
310 mutex_lock(&sl->master->mutex);
311
312 /* Write the PIO data */
313 if (w1_reset_select_slave(sl)) {
314 mutex_unlock(&sl->master->mutex);
315 return -1;
316 }
317
318 /* set bit 7..2 to value '1' */
319 *buf = *buf | 0xFC;
320
321 wrbuf[0] = W1_F1C_ACCESS_WRITE;
322 wrbuf[1] = *buf;
323 wrbuf[2] = ~(*buf);
324 w1_write_block(sl->master, wrbuf, 3);
325
326 w1_read_block(sl->master, &ack, sizeof(ack));
327
328 mutex_unlock(&sl->master->mutex);
329
330 /* check for acknowledgement */
331 if (ack != 0xAA)
332 return -EIO;
333
334 return count;
335 }
336
337 static BIN_ATTR_RW(pio, 1);
338
crccheck_show(struct device * dev,struct device_attribute * attr,char * buf)339 static ssize_t crccheck_show(struct device *dev, struct device_attribute *attr,
340 char *buf)
341 {
342 return sysfs_emit(buf, "%d\n", w1_enable_crccheck);
343 }
344
crccheck_store(struct device * dev,struct device_attribute * attr,const char * buf,size_t count)345 static ssize_t crccheck_store(struct device *dev, struct device_attribute *attr,
346 const char *buf, size_t count)
347 {
348 int err = kstrtobool(buf, &w1_enable_crccheck);
349
350 if (err)
351 return err;
352
353 return count;
354 }
355
356 static DEVICE_ATTR_RW(crccheck);
357
358 static struct attribute *w1_f1C_attrs[] = {
359 &dev_attr_crccheck.attr,
360 NULL,
361 };
362
363 static struct bin_attribute *w1_f1C_bin_attrs[] = {
364 &bin_attr_eeprom,
365 &bin_attr_pio,
366 NULL,
367 };
368
369 static const struct attribute_group w1_f1C_group = {
370 .attrs = w1_f1C_attrs,
371 .bin_attrs = w1_f1C_bin_attrs,
372 };
373
374 static const struct attribute_group *w1_f1C_groups[] = {
375 &w1_f1C_group,
376 NULL,
377 };
378
w1_f1C_add_slave(struct w1_slave * sl)379 static int w1_f1C_add_slave(struct w1_slave *sl)
380 {
381 struct w1_f1C_data *data = NULL;
382
383 if (w1_enable_crccheck) {
384 data = kzalloc(sizeof(struct w1_f1C_data), GFP_KERNEL);
385 if (!data)
386 return -ENOMEM;
387 sl->family_data = data;
388 }
389
390 return 0;
391 }
392
w1_f1C_remove_slave(struct w1_slave * sl)393 static void w1_f1C_remove_slave(struct w1_slave *sl)
394 {
395 kfree(sl->family_data);
396 sl->family_data = NULL;
397 }
398
399 static const struct w1_family_ops w1_f1C_fops = {
400 .add_slave = w1_f1C_add_slave,
401 .remove_slave = w1_f1C_remove_slave,
402 .groups = w1_f1C_groups,
403 };
404
405 static struct w1_family w1_family_1C = {
406 .fid = W1_FAMILY_DS28E04,
407 .fops = &w1_f1C_fops,
408 };
409 module_w1_family(w1_family_1C);
410
411 MODULE_AUTHOR("Markus Franke <franke.m@sebakmt.com>, <franm@hrz.tu-chemnitz.de>");
412 MODULE_DESCRIPTION("w1 family 1C driver for DS28E04, 4kb EEPROM and PIO");
413 MODULE_LICENSE("GPL");
414 MODULE_ALIAS("w1-family-" __stringify(W1_FAMILY_DS28E04));
415