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 */
31static int w1_strong_pullup = 1;
32module_param_named(strong_pullup, w1_strong_pullup, int, 0);
33
34/* enable/disable CRC checking on DS28E04-100 memory accesses */
35static 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
51struct 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 */
60static 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
71static 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, buffer: &data->memory[off], W1_PAGE_SIZE) == CRC16_VALID)
93 data->validcrc |= (1 << block);
94
95 return 0;
96}
97
98static 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
114static 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, block: 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, addr: off, len: count, data: buf);
140 }
141
142out_up:
143 mutex_unlock(lock: &sl->master->mutex);
144
145 return count;
146}
147
148/**
149 * w1_f1C_write() - Writes to the scratchpad and reads it back for verification.
150 * @sl: The slave structure
151 * @addr: Address for the write
152 * @len: length must be <= (W1_PAGE_SIZE - (addr & W1_PAGE_MASK))
153 * @data: The data to write
154 *
155 * Then copies the scratchpad to EEPROM.
156 * The data must be on one page.
157 * The master must be locked.
158 *
159 * Return: 0=Success, -1=failure
160 */
161static int w1_f1C_write(struct w1_slave *sl, int addr, int len, const u8 *data)
162{
163 u8 wrbuf[4];
164 u8 rdbuf[W1_PAGE_SIZE + 3];
165 u8 es = (addr + len - 1) & 0x1f;
166 unsigned int tm = 10;
167 int i;
168 struct w1_f1C_data *f1C = sl->family_data;
169
170 /* Write the data to the scratchpad */
171 if (w1_reset_select_slave(sl))
172 return -1;
173
174 wrbuf[0] = W1_F1C_WRITE_SCRATCH;
175 wrbuf[1] = addr & 0xff;
176 wrbuf[2] = addr >> 8;
177
178 w1_write_block(sl->master, wrbuf, 3);
179 w1_write_block(sl->master, data, len);
180
181 /* Read the scratchpad and verify */
182 if (w1_reset_select_slave(sl))
183 return -1;
184
185 w1_write_8(sl->master, W1_F1C_READ_SCRATCH);
186 w1_read_block(sl->master, rdbuf, len + 3);
187
188 /* Compare what was read against the data written */
189 if ((rdbuf[0] != wrbuf[1]) || (rdbuf[1] != wrbuf[2]) ||
190 (rdbuf[2] != es) || (memcmp(p: data, q: &rdbuf[3], size: len) != 0))
191 return -1;
192
193 /* Copy the scratchpad to EEPROM */
194 if (w1_reset_select_slave(sl))
195 return -1;
196
197 wrbuf[0] = W1_F1C_COPY_SCRATCH;
198 wrbuf[3] = es;
199
200 for (i = 0; i < sizeof(wrbuf); ++i) {
201 /*
202 * issue 10ms strong pullup (or delay) on the last byte
203 * for writing the data from the scratchpad to EEPROM
204 */
205 if (w1_strong_pullup && i == sizeof(wrbuf)-1)
206 w1_next_pullup(sl->master, tm);
207
208 w1_write_8(sl->master, wrbuf[i]);
209 }
210
211 if (!w1_strong_pullup)
212 msleep(msecs: tm);
213
214 if (w1_enable_crccheck) {
215 /* invalidate cached data */
216 f1C->validcrc &= ~(1 << (addr >> W1_PAGE_BITS));
217 }
218
219 /* Reset the bus to wake up the EEPROM (this may not be needed) */
220 w1_reset_bus(sl->master);
221
222 return 0;
223}
224
225static ssize_t eeprom_write(struct file *filp, struct kobject *kobj,
226 struct bin_attribute *bin_attr, char *buf,
227 loff_t off, size_t count)
228
229{
230 struct w1_slave *sl = kobj_to_w1_slave(kobj);
231 int addr, len, idx;
232
233 count = w1_f1C_fix_count(off, count, W1_EEPROM_SIZE);
234 if (count == 0)
235 return 0;
236
237 if (w1_enable_crccheck) {
238 /* can only write full blocks in cached mode */
239 if ((off & W1_PAGE_MASK) || (count & W1_PAGE_MASK)) {
240 dev_err(&sl->dev, "invalid offset/count off=%d cnt=%zd\n",
241 (int)off, count);
242 return -EINVAL;
243 }
244
245 /* make sure the block CRCs are valid */
246 for (idx = 0; idx < count; idx += W1_PAGE_SIZE) {
247 if (crc16(CRC16_INIT, buffer: &buf[idx], W1_PAGE_SIZE)
248 != CRC16_VALID) {
249 dev_err(&sl->dev, "bad CRC at offset %d\n",
250 (int)off);
251 return -EINVAL;
252 }
253 }
254 }
255
256 mutex_lock(&sl->master->mutex);
257
258 /* Can only write data to one page at a time */
259 idx = 0;
260 while (idx < count) {
261 addr = off + idx;
262 len = W1_PAGE_SIZE - (addr & W1_PAGE_MASK);
263 if (len > (count - idx))
264 len = count - idx;
265
266 if (w1_f1C_write(sl, addr, len, data: &buf[idx]) < 0) {
267 count = -EIO;
268 goto out_up;
269 }
270 idx += len;
271 }
272
273out_up:
274 mutex_unlock(lock: &sl->master->mutex);
275
276 return count;
277}
278
279static BIN_ATTR_RW(eeprom, W1_EEPROM_SIZE);
280
281static ssize_t pio_read(struct file *filp, struct kobject *kobj,
282 struct bin_attribute *bin_attr, char *buf, loff_t off,
283 size_t count)
284
285{
286 struct w1_slave *sl = kobj_to_w1_slave(kobj);
287 int ret;
288
289 /* check arguments */
290 if (off != 0 || count != 1 || buf == NULL)
291 return -EINVAL;
292
293 mutex_lock(&sl->master->mutex);
294 ret = w1_f1C_read(sl, W1_1C_REG_LOGIC_STATE, len: count, data: buf);
295 mutex_unlock(lock: &sl->master->mutex);
296
297 return ret;
298}
299
300static ssize_t pio_write(struct file *filp, struct kobject *kobj,
301 struct bin_attribute *bin_attr, char *buf, loff_t off,
302 size_t count)
303
304{
305 struct w1_slave *sl = kobj_to_w1_slave(kobj);
306 u8 wrbuf[3];
307 u8 ack;
308
309 /* check arguments */
310 if (off != 0 || count != 1 || buf == NULL)
311 return -EINVAL;
312
313 mutex_lock(&sl->master->mutex);
314
315 /* Write the PIO data */
316 if (w1_reset_select_slave(sl)) {
317 mutex_unlock(lock: &sl->master->mutex);
318 return -1;
319 }
320
321 /* set bit 7..2 to value '1' */
322 *buf = *buf | 0xFC;
323
324 wrbuf[0] = W1_F1C_ACCESS_WRITE;
325 wrbuf[1] = *buf;
326 wrbuf[2] = ~(*buf);
327 w1_write_block(sl->master, wrbuf, 3);
328
329 w1_read_block(sl->master, &ack, sizeof(ack));
330
331 mutex_unlock(lock: &sl->master->mutex);
332
333 /* check for acknowledgement */
334 if (ack != 0xAA)
335 return -EIO;
336
337 return count;
338}
339
340static BIN_ATTR_RW(pio, 1);
341
342static ssize_t crccheck_show(struct device *dev, struct device_attribute *attr,
343 char *buf)
344{
345 return sysfs_emit(buf, fmt: "%d\n", w1_enable_crccheck);
346}
347
348static ssize_t crccheck_store(struct device *dev, struct device_attribute *attr,
349 const char *buf, size_t count)
350{
351 int err = kstrtobool(s: buf, res: &w1_enable_crccheck);
352
353 if (err)
354 return err;
355
356 return count;
357}
358
359static DEVICE_ATTR_RW(crccheck);
360
361static struct attribute *w1_f1C_attrs[] = {
362 &dev_attr_crccheck.attr,
363 NULL,
364};
365
366static struct bin_attribute *w1_f1C_bin_attrs[] = {
367 &bin_attr_eeprom,
368 &bin_attr_pio,
369 NULL,
370};
371
372static const struct attribute_group w1_f1C_group = {
373 .attrs = w1_f1C_attrs,
374 .bin_attrs = w1_f1C_bin_attrs,
375};
376
377static const struct attribute_group *w1_f1C_groups[] = {
378 &w1_f1C_group,
379 NULL,
380};
381
382static int w1_f1C_add_slave(struct w1_slave *sl)
383{
384 struct w1_f1C_data *data = NULL;
385
386 if (w1_enable_crccheck) {
387 data = kzalloc(size: sizeof(struct w1_f1C_data), GFP_KERNEL);
388 if (!data)
389 return -ENOMEM;
390 sl->family_data = data;
391 }
392
393 return 0;
394}
395
396static void w1_f1C_remove_slave(struct w1_slave *sl)
397{
398 kfree(objp: sl->family_data);
399 sl->family_data = NULL;
400}
401
402static const struct w1_family_ops w1_f1C_fops = {
403 .add_slave = w1_f1C_add_slave,
404 .remove_slave = w1_f1C_remove_slave,
405 .groups = w1_f1C_groups,
406};
407
408static struct w1_family w1_family_1C = {
409 .fid = W1_FAMILY_DS28E04,
410 .fops = &w1_f1C_fops,
411};
412module_w1_family(w1_family_1C);
413
414MODULE_AUTHOR("Markus Franke <franke.m@sebakmt.com>, <franm@hrz.tu-chemnitz.de>");
415MODULE_DESCRIPTION("w1 family 1C driver for DS28E04, 4kb EEPROM and PIO");
416MODULE_LICENSE("GPL");
417MODULE_ALIAS("w1-family-" __stringify(W1_FAMILY_DS28E04));
418

source code of linux/drivers/w1/slaves/w1_ds28e04.c