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1 | // SPDX-License-Identifier: GPL-2.0-or-later |
2 | /* | |
3 | * Hardware monitoring driver for Maxim MAX6620 | |
4 | * | |
5 | * Originally from L. Grunenberg. | |
6 | * (C) 2012 by L. Grunenberg <contact@lgrunenberg.de> | |
7 | * | |
8 | * Copyright (c) 2021 Dell Inc. or its subsidiaries. All Rights Reserved. | |
9 | * | |
10 | * based on code written by : | |
11 | * 2007 by Hans J. Koch <hjk@hansjkoch.de> | |
12 | * John Morris <john.morris@spirentcom.com> | |
13 | * Copyright (c) 2003 Spirent Communications | |
14 | * and Claus Gindhart <claus.gindhart@kontron.com> | |
15 | * | |
16 | * This module has only been tested with the MAX6620 chip. | |
17 | * | |
18 | * The datasheet was last seen at: | |
19 | * | |
20 | * http://pdfserv.maxim-ic.com/en/ds/MAX6620.pdf | |
21 | * | |
22 | */ | |
23 | ||
24 | #include <linux/bits.h> | |
25 | #include <linux/err.h> | |
26 | #include <linux/hwmon.h> | |
27 | #include <linux/i2c.h> | |
28 | #include <linux/init.h> | |
29 | #include <linux/jiffies.h> | |
30 | #include <linux/module.h> | |
31 | #include <linux/slab.h> | |
32 | ||
33 | /* | |
34 | * MAX 6620 registers | |
35 | */ | |
36 | ||
37 | #define MAX6620_REG_CONFIG 0x00 | |
38 | #define MAX6620_REG_FAULT 0x01 | |
39 | #define MAX6620_REG_CONF_FAN0 0x02 | |
40 | #define MAX6620_REG_CONF_FAN1 0x03 | |
41 | #define MAX6620_REG_CONF_FAN2 0x04 | |
42 | #define MAX6620_REG_CONF_FAN3 0x05 | |
43 | #define MAX6620_REG_DYN_FAN0 0x06 | |
44 | #define MAX6620_REG_DYN_FAN1 0x07 | |
45 | #define MAX6620_REG_DYN_FAN2 0x08 | |
46 | #define MAX6620_REG_DYN_FAN3 0x09 | |
47 | #define MAX6620_REG_TACH0 0x10 | |
48 | #define MAX6620_REG_TACH1 0x12 | |
49 | #define MAX6620_REG_TACH2 0x14 | |
50 | #define MAX6620_REG_TACH3 0x16 | |
51 | #define MAX6620_REG_VOLT0 0x18 | |
52 | #define MAX6620_REG_VOLT1 0x1A | |
53 | #define MAX6620_REG_VOLT2 0x1C | |
54 | #define MAX6620_REG_VOLT3 0x1E | |
55 | #define MAX6620_REG_TAR0 0x20 | |
56 | #define MAX6620_REG_TAR1 0x22 | |
57 | #define MAX6620_REG_TAR2 0x24 | |
58 | #define MAX6620_REG_TAR3 0x26 | |
59 | #define MAX6620_REG_DAC0 0x28 | |
60 | #define MAX6620_REG_DAC1 0x2A | |
61 | #define MAX6620_REG_DAC2 0x2C | |
62 | #define MAX6620_REG_DAC3 0x2E | |
63 | ||
64 | /* | |
65 | * Config register bits | |
66 | */ | |
67 | ||
68 | #define MAX6620_CFG_RUN BIT(7) | |
69 | #define MAX6620_CFG_POR BIT(6) | |
70 | #define MAX6620_CFG_TIMEOUT BIT(5) | |
71 | #define MAX6620_CFG_FULLFAN BIT(4) | |
72 | #define MAX6620_CFG_OSC BIT(3) | |
73 | #define MAX6620_CFG_WD_MASK (BIT(2) | BIT(1)) | |
74 | #define MAX6620_CFG_WD_2 BIT(1) | |
75 | #define MAX6620_CFG_WD_6 BIT(2) | |
76 | #define MAX6620_CFG_WD10 (BIT(2) | BIT(1)) | |
77 | #define MAX6620_CFG_WD BIT(0) | |
78 | ||
79 | /* | |
80 | * Failure status register bits | |
81 | */ | |
82 | ||
83 | #define MAX6620_FAIL_TACH0 BIT(4) | |
84 | #define MAX6620_FAIL_TACH1 BIT(5) | |
85 | #define MAX6620_FAIL_TACH2 BIT(6) | |
86 | #define MAX6620_FAIL_TACH3 BIT(7) | |
87 | #define MAX6620_FAIL_MASK0 BIT(0) | |
88 | #define MAX6620_FAIL_MASK1 BIT(1) | |
89 | #define MAX6620_FAIL_MASK2 BIT(2) | |
90 | #define MAX6620_FAIL_MASK3 BIT(3) | |
91 | ||
92 | #define MAX6620_CLOCK_FREQ 8192 /* Clock frequency in Hz */ | |
93 | #define MAX6620_PULSE_PER_REV 2 /* Tachometer pulses per revolution */ | |
94 | ||
95 | /* Minimum and maximum values of the FAN-RPM */ | |
96 | #define FAN_RPM_MIN 240 | |
97 | #define FAN_RPM_MAX 30000 | |
98 | ||
99 | static const u8 config_reg[] = { | |
100 | MAX6620_REG_CONF_FAN0, | |
101 | MAX6620_REG_CONF_FAN1, | |
102 | MAX6620_REG_CONF_FAN2, | |
103 | MAX6620_REG_CONF_FAN3, | |
104 | }; | |
105 | ||
106 | static const u8 dyn_reg[] = { | |
107 | MAX6620_REG_DYN_FAN0, | |
108 | MAX6620_REG_DYN_FAN1, | |
109 | MAX6620_REG_DYN_FAN2, | |
110 | MAX6620_REG_DYN_FAN3, | |
111 | }; | |
112 | ||
113 | static const u8 tach_reg[] = { | |
114 | MAX6620_REG_TACH0, | |
115 | MAX6620_REG_TACH1, | |
116 | MAX6620_REG_TACH2, | |
117 | MAX6620_REG_TACH3, | |
118 | }; | |
119 | ||
120 | static const u8 target_reg[] = { | |
121 | MAX6620_REG_TAR0, | |
122 | MAX6620_REG_TAR1, | |
123 | MAX6620_REG_TAR2, | |
124 | MAX6620_REG_TAR3, | |
125 | }; | |
126 | ||
127 | /* | |
128 | * Client data (each client gets its own) | |
129 | */ | |
130 | ||
131 | struct max6620_data { | |
132 | struct i2c_client *client; | |
133 | struct mutex update_lock; | |
134 | bool valid; /* false until following fields are valid */ | |
135 | unsigned long last_updated; /* in jiffies */ | |
136 | ||
137 | /* register values */ | |
138 | u8 fancfg[4]; | |
139 | u8 fandyn[4]; | |
140 | u8 fault; | |
141 | u16 tach[4]; | |
142 | u16 target[4]; | |
143 | }; | |
144 | ||
145 | static u8 max6620_fan_div_from_reg(u8 val) | |
146 | { | |
147 | return BIT((val & 0xE0) >> 5); | |
148 | } | |
149 | ||
150 | static u16 max6620_fan_rpm_to_tach(u8 div, int rpm) | |
151 | { | |
152 | return (60 * div * MAX6620_CLOCK_FREQ) / (rpm * MAX6620_PULSE_PER_REV); | |
153 | } | |
154 | ||
155 | static int max6620_fan_tach_to_rpm(u8 div, u16 tach) | |
156 | { | |
157 | return (60 * div * MAX6620_CLOCK_FREQ) / (tach * MAX6620_PULSE_PER_REV); | |
158 | } | |
159 | ||
160 | static int max6620_update_device(struct device *dev) | |
161 | { | |
162 | struct max6620_data *data = dev_get_drvdata(dev); | |
163 | struct i2c_client *client = data->client; | |
164 | int i; | |
165 | int ret = 0; | |
166 | ||
167 | mutex_lock(&data->update_lock); | |
168 | ||
169 | if (time_after(jiffies, data->last_updated + HZ) || !data->valid) { | |
170 | for (i = 0; i < 4; i++) { | |
171 | ret = i2c_smbus_read_byte_data(client, config_reg[i]); | |
172 | if (ret < 0) | |
173 | goto error; | |
174 | data->fancfg[i] = ret; | |
175 | ||
176 | ret = i2c_smbus_read_byte_data(client, dyn_reg[i]); | |
177 | if (ret < 0) | |
178 | goto error; | |
179 | data->fandyn[i] = ret; | |
180 | ||
181 | ret = i2c_smbus_read_byte_data(client, tach_reg[i]); | |
182 | if (ret < 0) | |
183 | goto error; | |
184 | data->tach[i] = (ret << 3) & 0x7f8; | |
185 | ret = i2c_smbus_read_byte_data(client, tach_reg[i] + 1); | |
186 | if (ret < 0) | |
187 | goto error; | |
188 | data->tach[i] |= (ret >> 5) & 0x7; | |
189 | ||
190 | ret = i2c_smbus_read_byte_data(client, target_reg[i]); | |
191 | if (ret < 0) | |
192 | goto error; | |
193 | data->target[i] = (ret << 3) & 0x7f8; | |
194 | ret = i2c_smbus_read_byte_data(client, target_reg[i] + 1); | |
195 | if (ret < 0) | |
196 | goto error; | |
197 | data->target[i] |= (ret >> 5) & 0x7; | |
198 | } | |
199 | ||
200 | /* | |
201 | * Alarms are cleared on read in case the condition that | |
202 | * caused the alarm is removed. Keep the value latched here | |
203 | * for providing the register through different alarm files. | |
204 | */ | |
205 | ret = i2c_smbus_read_byte_data(client, MAX6620_REG_FAULT); | |
206 | if (ret < 0) | |
207 | goto error; | |
208 | data->fault |= (ret >> 4) & (ret & 0x0F); | |
209 | ||
210 | data->last_updated = jiffies; | |
211 | data->valid = true; | |
212 | } | |
213 | ||
214 | error: | |
215 | mutex_unlock(&data->update_lock); | |
216 | return ret; | |
217 | } | |
218 | ||
219 | static umode_t | |
220 | max6620_is_visible(const void *data, enum hwmon_sensor_types type, u32 attr, | |
221 | int channel) | |
222 | { | |
223 | switch (type) { | |
224 | case hwmon_fan: | |
225 | switch (attr) { | |
226 | case hwmon_fan_alarm: | |
227 | case hwmon_fan_input: | |
228 | return 0444; | |
229 | case hwmon_fan_div: | |
230 | case hwmon_fan_target: | |
231 | return 0644; | |
232 | default: | |
233 | break; | |
234 | } | |
235 | break; | |
236 | default: | |
237 | break; | |
238 | } | |
239 | ||
240 | return 0; | |
241 | } | |
242 | ||
243 | static int | |
244 | max6620_read(struct device *dev, enum hwmon_sensor_types type, u32 attr, | |
245 | int channel, long *val) | |
246 | { | |
247 | struct max6620_data *data; | |
248 | struct i2c_client *client; | |
249 | int ret; | |
250 | u8 div; | |
251 | u8 val1; | |
252 | u8 val2; | |
253 | ||
254 | ret = max6620_update_device(dev); | |
255 | if (ret < 0) | |
256 | return ret; | |
257 | data = dev_get_drvdata(dev); | |
258 | client = data->client; | |
259 | ||
260 | switch (type) { | |
261 | case hwmon_fan: | |
262 | switch (attr) { | |
263 | case hwmon_fan_alarm: | |
264 | mutex_lock(&data->update_lock); | |
265 | *val = !!(data->fault & BIT(channel)); | |
266 | ||
267 | /* Setting TACH count to re-enable fan fault detection */ | |
268 | if (*val == 1) { | |
269 | val1 = (data->target[channel] >> 3) & 0xff; | |
270 | val2 = (data->target[channel] << 5) & 0xe0; | |
271 | ret = i2c_smbus_write_byte_data(client, | |
272 | target_reg[channel], val1); | |
273 | if (ret < 0) { | |
274 | mutex_unlock(&data->update_lock); | |
275 | return ret; | |
276 | } | |
277 | ret = i2c_smbus_write_byte_data(client, | |
278 | target_reg[channel] + 1, val2); | |
279 | if (ret < 0) { | |
280 | mutex_unlock(&data->update_lock); | |
281 | return ret; | |
282 | } | |
283 | ||
284 | data->fault &= ~BIT(channel); | |
285 | } | |
286 | mutex_unlock(&data->update_lock); | |
287 | ||
288 | break; | |
289 | case hwmon_fan_div: | |
290 | *val = max6620_fan_div_from_reg(data->fandyn[channel]); | |
291 | break; | |
292 | case hwmon_fan_input: | |
293 | if (data->tach[channel] == 0) { | |
294 | *val = 0; | |
295 | } else { | |
296 | div = max6620_fan_div_from_reg(data->fandyn[channel]); | |
297 | *val = max6620_fan_tach_to_rpm(div, data->tach[channel]); | |
298 | } | |
299 | break; | |
300 | case hwmon_fan_target: | |
301 | if (data->target[channel] == 0) { | |
302 | *val = 0; | |
303 | } else { | |
304 | div = max6620_fan_div_from_reg(data->fandyn[channel]); | |
305 | *val = max6620_fan_tach_to_rpm(div, data->target[channel]); | |
306 | } | |
307 | break; | |
308 | default: | |
309 | return -EOPNOTSUPP; | |
310 | } | |
311 | break; | |
312 | ||
313 | default: | |
314 | return -EOPNOTSUPP; | |
315 | } | |
316 | ||
317 | return 0; | |
318 | } | |
319 | ||
320 | static int | |
321 | max6620_write(struct device *dev, enum hwmon_sensor_types type, u32 attr, | |
322 | int channel, long val) | |
323 | { | |
324 | struct max6620_data *data; | |
325 | struct i2c_client *client; | |
326 | int ret; | |
327 | u8 div; | |
328 | u16 tach; | |
329 | u8 val1; | |
330 | u8 val2; | |
331 | ||
332 | ret = max6620_update_device(dev); | |
333 | if (ret < 0) | |
334 | return ret; | |
335 | data = dev_get_drvdata(dev); | |
336 | client = data->client; | |
337 | mutex_lock(&data->update_lock); | |
338 | ||
339 | switch (type) { | |
340 | case hwmon_fan: | |
341 | switch (attr) { | |
342 | case hwmon_fan_div: | |
343 | switch (val) { | |
344 | case 1: | |
345 | div = 0; | |
346 | break; | |
347 | case 2: | |
348 | div = 1; | |
349 | break; | |
350 | case 4: | |
351 | div = 2; | |
352 | break; | |
353 | case 8: | |
354 | div = 3; | |
355 | break; | |
356 | case 16: | |
357 | div = 4; | |
358 | break; | |
359 | case 32: | |
360 | div = 5; | |
361 | break; | |
362 | default: | |
363 | ret = -EINVAL; | |
364 | goto error; | |
365 | } | |
366 | data->fandyn[channel] &= 0x1F; | |
367 | data->fandyn[channel] |= div << 5; | |
368 | ret = i2c_smbus_write_byte_data(client, dyn_reg[channel], | |
369 | data->fandyn[channel]); | |
370 | break; | |
371 | case hwmon_fan_target: | |
372 | val = clamp_val(val, FAN_RPM_MIN, FAN_RPM_MAX); | |
373 | div = max6620_fan_div_from_reg(data->fandyn[channel]); | |
374 | tach = max6620_fan_rpm_to_tach(div, val); | |
375 | val1 = (tach >> 3) & 0xff; | |
376 | val2 = (tach << 5) & 0xe0; | |
377 | ret = i2c_smbus_write_byte_data(client, target_reg[channel], val1); | |
378 | if (ret < 0) | |
379 | break; | |
380 | ret = i2c_smbus_write_byte_data(client, target_reg[channel] + 1, val2); | |
381 | if (ret < 0) | |
382 | break; | |
383 | ||
384 | /* Setting TACH count re-enables fan fault detection */ | |
385 | data->fault &= ~BIT(channel); | |
386 | ||
387 | break; | |
388 | default: | |
389 | ret = -EOPNOTSUPP; | |
390 | break; | |
391 | } | |
392 | break; | |
393 | ||
394 | default: | |
395 | ret = -EOPNOTSUPP; | |
396 | break; | |
397 | } | |
398 | ||
399 | error: | |
400 | mutex_unlock(&data->update_lock); | |
401 | return ret; | |
402 | } | |
403 | ||
b3fcd02c | 404 | static const struct hwmon_channel_info * const max6620_info[] = { |
e8ac01e5 ASB |
405 | HWMON_CHANNEL_INFO(fan, |
406 | HWMON_F_INPUT | HWMON_F_DIV | HWMON_F_TARGET | HWMON_F_ALARM, | |
407 | HWMON_F_INPUT | HWMON_F_DIV | HWMON_F_TARGET | HWMON_F_ALARM, | |
408 | HWMON_F_INPUT | HWMON_F_DIV | HWMON_F_TARGET | HWMON_F_ALARM, | |
409 | HWMON_F_INPUT | HWMON_F_DIV | HWMON_F_TARGET | HWMON_F_ALARM), | |
410 | NULL | |
411 | }; | |
412 | ||
413 | static const struct hwmon_ops max6620_hwmon_ops = { | |
414 | .read = max6620_read, | |
415 | .write = max6620_write, | |
416 | .is_visible = max6620_is_visible, | |
417 | }; | |
418 | ||
419 | static const struct hwmon_chip_info max6620_chip_info = { | |
420 | .ops = &max6620_hwmon_ops, | |
421 | .info = max6620_info, | |
422 | }; | |
423 | ||
424 | static int max6620_init_client(struct max6620_data *data) | |
425 | { | |
426 | struct i2c_client *client = data->client; | |
427 | int config; | |
428 | int err; | |
429 | int i; | |
430 | int reg; | |
431 | ||
432 | config = i2c_smbus_read_byte_data(client, MAX6620_REG_CONFIG); | |
433 | if (config < 0) { | |
434 | dev_err(&client->dev, "Error reading config, aborting.\n"); | |
435 | return config; | |
436 | } | |
437 | ||
438 | /* | |
439 | * Set bit 4, disable other fans from going full speed on a fail | |
440 | * failure. | |
441 | */ | |
442 | err = i2c_smbus_write_byte_data(client, MAX6620_REG_CONFIG, config | 0x10); | |
443 | if (err < 0) { | |
444 | dev_err(&client->dev, "Config write error, aborting.\n"); | |
445 | return err; | |
446 | } | |
447 | ||
448 | for (i = 0; i < 4; i++) { | |
449 | reg = i2c_smbus_read_byte_data(client, config_reg[i]); | |
450 | if (reg < 0) | |
451 | return reg; | |
452 | data->fancfg[i] = reg; | |
453 | ||
454 | /* Enable RPM mode */ | |
455 | data->fancfg[i] |= 0xa8; | |
456 | err = i2c_smbus_write_byte_data(client, config_reg[i], data->fancfg[i]); | |
457 | if (err < 0) | |
458 | return err; | |
459 | ||
460 | /* 2 counts (001) and Rate change 100 (0.125 secs) */ | |
461 | data->fandyn[i] = 0x30; | |
462 | err = i2c_smbus_write_byte_data(client, dyn_reg[i], data->fandyn[i]); | |
463 | if (err < 0) | |
464 | return err; | |
465 | } | |
466 | return 0; | |
467 | } | |
468 | ||
469 | static int max6620_probe(struct i2c_client *client) | |
470 | { | |
471 | struct device *dev = &client->dev; | |
472 | struct max6620_data *data; | |
473 | struct device *hwmon_dev; | |
474 | int err; | |
475 | ||
476 | data = devm_kzalloc(dev, sizeof(struct max6620_data), GFP_KERNEL); | |
477 | if (!data) | |
478 | return -ENOMEM; | |
479 | ||
480 | data->client = client; | |
481 | mutex_init(&data->update_lock); | |
482 | ||
483 | err = max6620_init_client(data); | |
484 | if (err) | |
485 | return err; | |
486 | ||
487 | hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name, | |
488 | data, | |
489 | &max6620_chip_info, | |
490 | NULL); | |
491 | ||
492 | return PTR_ERR_OR_ZERO(hwmon_dev); | |
493 | } | |
494 | ||
495 | static const struct i2c_device_id max6620_id[] = { | |
496 | { "max6620", 0 }, | |
497 | { } | |
498 | }; | |
499 | MODULE_DEVICE_TABLE(i2c, max6620_id); | |
500 | ||
501 | static struct i2c_driver max6620_driver = { | |
502 | .class = I2C_CLASS_HWMON, | |
503 | .driver = { | |
504 | .name = "max6620", | |
505 | }, | |
1975d167 | 506 | .probe = max6620_probe, |
e8ac01e5 ASB |
507 | .id_table = max6620_id, |
508 | }; | |
509 | ||
510 | module_i2c_driver(max6620_driver); | |
511 | ||
512 | MODULE_AUTHOR("Lucas Grunenberg"); | |
513 | MODULE_DESCRIPTION("MAX6620 sensor driver"); | |
514 | MODULE_LICENSE("GPL"); |