1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | /* |
3 | * 1-Wire implementation for the ds2438 chip |
4 | * |
5 | * Copyright (c) 2017 Mariusz Bialonczyk <manio@skyboo.net> |
6 | */ |
7 | |
8 | #include <linux/kernel.h> |
9 | #include <linux/module.h> |
10 | #include <linux/device.h> |
11 | #include <linux/types.h> |
12 | #include <linux/delay.h> |
13 | |
14 | #include <linux/w1.h> |
15 | |
16 | #define W1_FAMILY_DS2438 0x26 |
17 | |
18 | #define W1_DS2438_RETRIES 3 |
19 | |
20 | /* Memory commands */ |
21 | #define W1_DS2438_READ_SCRATCH 0xBE |
22 | #define W1_DS2438_WRITE_SCRATCH 0x4E |
23 | #define W1_DS2438_COPY_SCRATCH 0x48 |
24 | #define W1_DS2438_RECALL_MEMORY 0xB8 |
25 | /* Register commands */ |
26 | #define W1_DS2438_CONVERT_TEMP 0x44 |
27 | #define W1_DS2438_CONVERT_VOLTAGE 0xB4 |
28 | |
29 | #define DS2438_PAGE_SIZE 8 |
30 | #define DS2438_ADC_INPUT_VAD 0 |
31 | #define DS2438_ADC_INPUT_VDD 1 |
32 | #define DS2438_MAX_CONVERSION_TIME 10 /* ms */ |
33 | |
34 | /* Page #0 definitions */ |
35 | #define DS2438_STATUS_REG 0x00 /* Status/Configuration Register */ |
36 | #define DS2438_STATUS_IAD (1 << 0) /* Current A/D Control Bit */ |
37 | #define DS2438_STATUS_CA (1 << 1) /* Current Accumulator Configuration */ |
38 | #define DS2438_STATUS_EE (1 << 2) /* Current Accumulator Shadow Selector bit */ |
39 | #define DS2438_STATUS_AD (1 << 3) /* Voltage A/D Input Select Bit */ |
40 | #define DS2438_STATUS_TB (1 << 4) /* Temperature Busy Flag */ |
41 | #define DS2438_STATUS_NVB (1 << 5) /* Nonvolatile Memory Busy Flag */ |
42 | #define DS2438_STATUS_ADB (1 << 6) /* A/D Converter Busy Flag */ |
43 | |
44 | #define DS2438_TEMP_LSB 0x01 |
45 | #define DS2438_TEMP_MSB 0x02 |
46 | #define DS2438_VOLTAGE_LSB 0x03 |
47 | #define DS2438_VOLTAGE_MSB 0x04 |
48 | #define DS2438_CURRENT_LSB 0x05 |
49 | #define DS2438_CURRENT_MSB 0x06 |
50 | #define DS2438_THRESHOLD 0x07 |
51 | |
52 | /* Page #1 definitions */ |
53 | #define DS2438_ETM_0 0x00 |
54 | #define DS2438_ETM_1 0x01 |
55 | #define DS2438_ETM_2 0x02 |
56 | #define DS2438_ETM_3 0x03 |
57 | #define DS2438_ICA 0x04 |
58 | #define DS2438_OFFSET_LSB 0x05 |
59 | #define DS2438_OFFSET_MSB 0x06 |
60 | |
61 | static int w1_ds2438_get_page(struct w1_slave *sl, int pageno, u8 *buf) |
62 | { |
63 | unsigned int retries = W1_DS2438_RETRIES; |
64 | u8 w1_buf[2]; |
65 | u8 crc; |
66 | size_t count; |
67 | |
68 | while (retries--) { |
69 | if (w1_reset_select_slave(sl)) |
70 | continue; |
71 | w1_buf[0] = W1_DS2438_RECALL_MEMORY; |
72 | w1_buf[1] = (u8)pageno; |
73 | w1_write_block(sl->master, w1_buf, 2); |
74 | |
75 | if (w1_reset_select_slave(sl)) |
76 | continue; |
77 | w1_buf[0] = W1_DS2438_READ_SCRATCH; |
78 | w1_buf[1] = (u8)pageno; |
79 | w1_write_block(sl->master, w1_buf, 2); |
80 | |
81 | count = w1_read_block(sl->master, buf, DS2438_PAGE_SIZE + 1); |
82 | if (count == DS2438_PAGE_SIZE + 1) { |
83 | crc = w1_calc_crc8(buf, DS2438_PAGE_SIZE); |
84 | |
85 | /* check for correct CRC */ |
86 | if ((u8)buf[DS2438_PAGE_SIZE] == crc) |
87 | return 0; |
88 | } |
89 | } |
90 | return -1; |
91 | } |
92 | |
93 | static int w1_ds2438_get_temperature(struct w1_slave *sl, int16_t *temperature) |
94 | { |
95 | unsigned int retries = W1_DS2438_RETRIES; |
96 | u8 w1_buf[DS2438_PAGE_SIZE + 1 /*for CRC*/]; |
97 | unsigned int tm = DS2438_MAX_CONVERSION_TIME; |
98 | unsigned long sleep_rem; |
99 | int ret; |
100 | |
101 | mutex_lock(&sl->master->bus_mutex); |
102 | |
103 | while (retries--) { |
104 | if (w1_reset_select_slave(sl)) |
105 | continue; |
106 | w1_write_8(sl->master, W1_DS2438_CONVERT_TEMP); |
107 | |
108 | mutex_unlock(lock: &sl->master->bus_mutex); |
109 | sleep_rem = msleep_interruptible(msecs: tm); |
110 | if (sleep_rem != 0) { |
111 | ret = -1; |
112 | goto post_unlock; |
113 | } |
114 | |
115 | if (mutex_lock_interruptible(&sl->master->bus_mutex) != 0) { |
116 | ret = -1; |
117 | goto post_unlock; |
118 | } |
119 | |
120 | break; |
121 | } |
122 | |
123 | if (w1_ds2438_get_page(sl, pageno: 0, buf: w1_buf) == 0) { |
124 | *temperature = (((int16_t) w1_buf[DS2438_TEMP_MSB]) << 8) | ((uint16_t) w1_buf[DS2438_TEMP_LSB]); |
125 | ret = 0; |
126 | } else |
127 | ret = -1; |
128 | |
129 | mutex_unlock(lock: &sl->master->bus_mutex); |
130 | |
131 | post_unlock: |
132 | return ret; |
133 | } |
134 | |
135 | static int w1_ds2438_change_config_bit(struct w1_slave *sl, u8 mask, u8 value) |
136 | { |
137 | unsigned int retries = W1_DS2438_RETRIES; |
138 | u8 w1_buf[3]; |
139 | u8 status; |
140 | int perform_write = 0; |
141 | |
142 | while (retries--) { |
143 | if (w1_reset_select_slave(sl)) |
144 | continue; |
145 | w1_buf[0] = W1_DS2438_RECALL_MEMORY; |
146 | w1_buf[1] = 0x00; |
147 | w1_write_block(sl->master, w1_buf, 2); |
148 | |
149 | if (w1_reset_select_slave(sl)) |
150 | continue; |
151 | w1_buf[0] = W1_DS2438_READ_SCRATCH; |
152 | w1_buf[1] = 0x00; |
153 | w1_write_block(sl->master, w1_buf, 2); |
154 | |
155 | /* reading one byte of result */ |
156 | status = w1_read_8(sl->master); |
157 | |
158 | /* if bit0=1, set a value to a mask for easy compare */ |
159 | if (value) |
160 | value = mask; |
161 | |
162 | if ((status & mask) == value) |
163 | return 0; /* already set as requested */ |
164 | |
165 | /* changing bit */ |
166 | status ^= mask; |
167 | perform_write = 1; |
168 | |
169 | break; |
170 | } |
171 | |
172 | if (perform_write) { |
173 | retries = W1_DS2438_RETRIES; |
174 | while (retries--) { |
175 | if (w1_reset_select_slave(sl)) |
176 | continue; |
177 | w1_buf[0] = W1_DS2438_WRITE_SCRATCH; |
178 | w1_buf[1] = 0x00; |
179 | w1_buf[2] = status; |
180 | w1_write_block(sl->master, w1_buf, 3); |
181 | |
182 | if (w1_reset_select_slave(sl)) |
183 | continue; |
184 | w1_buf[0] = W1_DS2438_COPY_SCRATCH; |
185 | w1_buf[1] = 0x00; |
186 | w1_write_block(sl->master, w1_buf, 2); |
187 | |
188 | return 0; |
189 | } |
190 | } |
191 | return -1; |
192 | } |
193 | |
194 | static int w1_ds2438_change_offset_register(struct w1_slave *sl, u8 *value) |
195 | { |
196 | unsigned int retries = W1_DS2438_RETRIES; |
197 | u8 w1_buf[9]; |
198 | u8 w1_page1_buf[DS2438_PAGE_SIZE + 1 /*for CRC*/]; |
199 | |
200 | if (w1_ds2438_get_page(sl, pageno: 1, buf: w1_page1_buf) == 0) { |
201 | memcpy(&w1_buf[2], w1_page1_buf, DS2438_PAGE_SIZE - 1); /* last register reserved */ |
202 | w1_buf[7] = value[0]; /* change only offset register */ |
203 | w1_buf[8] = value[1]; |
204 | while (retries--) { |
205 | if (w1_reset_select_slave(sl)) |
206 | continue; |
207 | w1_buf[0] = W1_DS2438_WRITE_SCRATCH; |
208 | w1_buf[1] = 0x01; /* write to page 1 */ |
209 | w1_write_block(sl->master, w1_buf, 9); |
210 | |
211 | if (w1_reset_select_slave(sl)) |
212 | continue; |
213 | w1_buf[0] = W1_DS2438_COPY_SCRATCH; |
214 | w1_buf[1] = 0x01; |
215 | w1_write_block(sl->master, w1_buf, 2); |
216 | return 0; |
217 | } |
218 | } |
219 | return -1; |
220 | } |
221 | |
222 | static int w1_ds2438_get_voltage(struct w1_slave *sl, |
223 | int adc_input, uint16_t *voltage) |
224 | { |
225 | unsigned int retries = W1_DS2438_RETRIES; |
226 | u8 w1_buf[DS2438_PAGE_SIZE + 1 /*for CRC*/]; |
227 | unsigned int tm = DS2438_MAX_CONVERSION_TIME; |
228 | unsigned long sleep_rem; |
229 | int ret; |
230 | |
231 | mutex_lock(&sl->master->bus_mutex); |
232 | |
233 | if (w1_ds2438_change_config_bit(sl, DS2438_STATUS_AD, value: adc_input)) { |
234 | ret = -1; |
235 | goto pre_unlock; |
236 | } |
237 | |
238 | while (retries--) { |
239 | if (w1_reset_select_slave(sl)) |
240 | continue; |
241 | w1_write_8(sl->master, W1_DS2438_CONVERT_VOLTAGE); |
242 | |
243 | mutex_unlock(lock: &sl->master->bus_mutex); |
244 | sleep_rem = msleep_interruptible(msecs: tm); |
245 | if (sleep_rem != 0) { |
246 | ret = -1; |
247 | goto post_unlock; |
248 | } |
249 | |
250 | if (mutex_lock_interruptible(&sl->master->bus_mutex) != 0) { |
251 | ret = -1; |
252 | goto post_unlock; |
253 | } |
254 | |
255 | break; |
256 | } |
257 | |
258 | if (w1_ds2438_get_page(sl, pageno: 0, buf: w1_buf) == 0) { |
259 | *voltage = (((uint16_t) w1_buf[DS2438_VOLTAGE_MSB]) << 8) | ((uint16_t) w1_buf[DS2438_VOLTAGE_LSB]); |
260 | ret = 0; |
261 | } else |
262 | ret = -1; |
263 | |
264 | pre_unlock: |
265 | mutex_unlock(lock: &sl->master->bus_mutex); |
266 | |
267 | post_unlock: |
268 | return ret; |
269 | } |
270 | |
271 | static int w1_ds2438_get_current(struct w1_slave *sl, int16_t *voltage) |
272 | { |
273 | u8 w1_buf[DS2438_PAGE_SIZE + 1 /*for CRC*/]; |
274 | int ret; |
275 | |
276 | mutex_lock(&sl->master->bus_mutex); |
277 | |
278 | if (w1_ds2438_get_page(sl, pageno: 0, buf: w1_buf) == 0) { |
279 | /* The voltage measured across current sense resistor RSENS. */ |
280 | *voltage = (((int16_t) w1_buf[DS2438_CURRENT_MSB]) << 8) | ((int16_t) w1_buf[DS2438_CURRENT_LSB]); |
281 | ret = 0; |
282 | } else |
283 | ret = -1; |
284 | |
285 | mutex_unlock(lock: &sl->master->bus_mutex); |
286 | |
287 | return ret; |
288 | } |
289 | |
290 | static ssize_t iad_write(struct file *filp, struct kobject *kobj, |
291 | struct bin_attribute *bin_attr, char *buf, |
292 | loff_t off, size_t count) |
293 | { |
294 | struct w1_slave *sl = kobj_to_w1_slave(kobj); |
295 | int ret; |
296 | |
297 | if (count != 1 || off != 0) |
298 | return -EFAULT; |
299 | |
300 | mutex_lock(&sl->master->bus_mutex); |
301 | |
302 | if (w1_ds2438_change_config_bit(sl, DS2438_STATUS_IAD, value: *buf & 0x01) == 0) |
303 | ret = 1; |
304 | else |
305 | ret = -EIO; |
306 | |
307 | mutex_unlock(lock: &sl->master->bus_mutex); |
308 | |
309 | return ret; |
310 | } |
311 | |
312 | static ssize_t iad_read(struct file *filp, struct kobject *kobj, |
313 | struct bin_attribute *bin_attr, char *buf, |
314 | loff_t off, size_t count) |
315 | { |
316 | struct w1_slave *sl = kobj_to_w1_slave(kobj); |
317 | int ret; |
318 | int16_t voltage; |
319 | |
320 | if (off != 0) |
321 | return 0; |
322 | if (!buf) |
323 | return -EINVAL; |
324 | |
325 | if (w1_ds2438_get_current(sl, voltage: &voltage) == 0) |
326 | ret = snprintf(buf, size: count, fmt: "%i\n" , voltage); |
327 | else |
328 | ret = -EIO; |
329 | |
330 | return ret; |
331 | } |
332 | |
333 | static ssize_t page0_read(struct file *filp, struct kobject *kobj, |
334 | struct bin_attribute *bin_attr, char *buf, |
335 | loff_t off, size_t count) |
336 | { |
337 | struct w1_slave *sl = kobj_to_w1_slave(kobj); |
338 | int ret; |
339 | u8 w1_buf[DS2438_PAGE_SIZE + 1 /*for CRC*/]; |
340 | |
341 | if (off != 0) |
342 | return 0; |
343 | if (!buf) |
344 | return -EINVAL; |
345 | |
346 | mutex_lock(&sl->master->bus_mutex); |
347 | |
348 | /* Read no more than page0 size */ |
349 | if (count > DS2438_PAGE_SIZE) |
350 | count = DS2438_PAGE_SIZE; |
351 | |
352 | if (w1_ds2438_get_page(sl, pageno: 0, buf: w1_buf) == 0) { |
353 | memcpy(buf, &w1_buf, count); |
354 | ret = count; |
355 | } else |
356 | ret = -EIO; |
357 | |
358 | mutex_unlock(lock: &sl->master->bus_mutex); |
359 | |
360 | return ret; |
361 | } |
362 | |
363 | static ssize_t page1_read(struct file *filp, struct kobject *kobj, |
364 | struct bin_attribute *bin_attr, char *buf, |
365 | loff_t off, size_t count) |
366 | { |
367 | struct w1_slave *sl = kobj_to_w1_slave(kobj); |
368 | int ret; |
369 | u8 w1_buf[DS2438_PAGE_SIZE + 1 /*for CRC*/]; |
370 | |
371 | if (off != 0) |
372 | return 0; |
373 | if (!buf) |
374 | return -EINVAL; |
375 | |
376 | mutex_lock(&sl->master->bus_mutex); |
377 | |
378 | /* Read no more than page1 size */ |
379 | if (count > DS2438_PAGE_SIZE) |
380 | count = DS2438_PAGE_SIZE; |
381 | |
382 | if (w1_ds2438_get_page(sl, pageno: 1, buf: w1_buf) == 0) { |
383 | memcpy(buf, &w1_buf, count); |
384 | ret = count; |
385 | } else |
386 | ret = -EIO; |
387 | |
388 | mutex_unlock(lock: &sl->master->bus_mutex); |
389 | |
390 | return ret; |
391 | } |
392 | |
393 | static ssize_t offset_write(struct file *filp, struct kobject *kobj, |
394 | struct bin_attribute *bin_attr, char *buf, |
395 | loff_t off, size_t count) |
396 | { |
397 | struct w1_slave *sl = kobj_to_w1_slave(kobj); |
398 | int ret; |
399 | |
400 | mutex_lock(&sl->master->bus_mutex); |
401 | |
402 | if (w1_ds2438_change_offset_register(sl, value: buf) == 0) |
403 | ret = count; |
404 | else |
405 | ret = -EIO; |
406 | |
407 | mutex_unlock(lock: &sl->master->bus_mutex); |
408 | |
409 | return ret; |
410 | } |
411 | |
412 | static ssize_t temperature_read(struct file *filp, struct kobject *kobj, |
413 | struct bin_attribute *bin_attr, char *buf, |
414 | loff_t off, size_t count) |
415 | { |
416 | struct w1_slave *sl = kobj_to_w1_slave(kobj); |
417 | int ret; |
418 | int16_t temp; |
419 | |
420 | if (off != 0) |
421 | return 0; |
422 | if (!buf) |
423 | return -EINVAL; |
424 | |
425 | if (w1_ds2438_get_temperature(sl, temperature: &temp) == 0) |
426 | ret = snprintf(buf, size: count, fmt: "%i\n" , temp); |
427 | else |
428 | ret = -EIO; |
429 | |
430 | return ret; |
431 | } |
432 | |
433 | static ssize_t vad_read(struct file *filp, struct kobject *kobj, |
434 | struct bin_attribute *bin_attr, char *buf, |
435 | loff_t off, size_t count) |
436 | { |
437 | struct w1_slave *sl = kobj_to_w1_slave(kobj); |
438 | int ret; |
439 | uint16_t voltage; |
440 | |
441 | if (off != 0) |
442 | return 0; |
443 | if (!buf) |
444 | return -EINVAL; |
445 | |
446 | if (w1_ds2438_get_voltage(sl, DS2438_ADC_INPUT_VAD, voltage: &voltage) == 0) |
447 | ret = snprintf(buf, size: count, fmt: "%u\n" , voltage); |
448 | else |
449 | ret = -EIO; |
450 | |
451 | return ret; |
452 | } |
453 | |
454 | static ssize_t vdd_read(struct file *filp, struct kobject *kobj, |
455 | struct bin_attribute *bin_attr, char *buf, |
456 | loff_t off, size_t count) |
457 | { |
458 | struct w1_slave *sl = kobj_to_w1_slave(kobj); |
459 | int ret; |
460 | uint16_t voltage; |
461 | |
462 | if (off != 0) |
463 | return 0; |
464 | if (!buf) |
465 | return -EINVAL; |
466 | |
467 | if (w1_ds2438_get_voltage(sl, DS2438_ADC_INPUT_VDD, voltage: &voltage) == 0) |
468 | ret = snprintf(buf, size: count, fmt: "%u\n" , voltage); |
469 | else |
470 | ret = -EIO; |
471 | |
472 | return ret; |
473 | } |
474 | |
475 | static BIN_ATTR_RW(iad, 0); |
476 | static BIN_ATTR_RO(page0, DS2438_PAGE_SIZE); |
477 | static BIN_ATTR_RO(page1, DS2438_PAGE_SIZE); |
478 | static BIN_ATTR_WO(offset, 2); |
479 | static BIN_ATTR_RO(temperature, 0/* real length varies */); |
480 | static BIN_ATTR_RO(vad, 0/* real length varies */); |
481 | static BIN_ATTR_RO(vdd, 0/* real length varies */); |
482 | |
483 | static struct bin_attribute *w1_ds2438_bin_attrs[] = { |
484 | &bin_attr_iad, |
485 | &bin_attr_page0, |
486 | &bin_attr_page1, |
487 | &bin_attr_offset, |
488 | &bin_attr_temperature, |
489 | &bin_attr_vad, |
490 | &bin_attr_vdd, |
491 | NULL, |
492 | }; |
493 | |
494 | static const struct attribute_group w1_ds2438_group = { |
495 | .bin_attrs = w1_ds2438_bin_attrs, |
496 | }; |
497 | |
498 | static const struct attribute_group *w1_ds2438_groups[] = { |
499 | &w1_ds2438_group, |
500 | NULL, |
501 | }; |
502 | |
503 | static const struct w1_family_ops w1_ds2438_fops = { |
504 | .groups = w1_ds2438_groups, |
505 | }; |
506 | |
507 | static struct w1_family w1_ds2438_family = { |
508 | .fid = W1_FAMILY_DS2438, |
509 | .fops = &w1_ds2438_fops, |
510 | }; |
511 | module_w1_family(w1_ds2438_family); |
512 | |
513 | MODULE_LICENSE("GPL" ); |
514 | MODULE_AUTHOR("Mariusz Bialonczyk <manio@skyboo.net>" ); |
515 | MODULE_DESCRIPTION("1-wire driver for Maxim/Dallas DS2438 Smart Battery Monitor" ); |
516 | MODULE_ALIAS("w1-family-" __stringify(W1_FAMILY_DS2438)); |
517 | |