1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * max31790.c - Part of lm_sensors, Linux kernel modules for hardware
4 * monitoring.
5 *
6 * (C) 2015 by Il Han <corone.il.han@gmail.com>
7 */
8
9#include <linux/err.h>
10#include <linux/hwmon.h>
11#include <linux/i2c.h>
12#include <linux/init.h>
13#include <linux/jiffies.h>
14#include <linux/module.h>
15#include <linux/slab.h>
16
17/* MAX31790 registers */
18#define MAX31790_REG_GLOBAL_CONFIG 0x00
19#define MAX31790_REG_FAN_CONFIG(ch) (0x02 + (ch))
20#define MAX31790_REG_FAN_DYNAMICS(ch) (0x08 + (ch))
21#define MAX31790_REG_FAN_FAULT_STATUS2 0x10
22#define MAX31790_REG_FAN_FAULT_STATUS1 0x11
23#define MAX31790_REG_TACH_COUNT(ch) (0x18 + (ch) * 2)
24#define MAX31790_REG_PWM_DUTY_CYCLE(ch) (0x30 + (ch) * 2)
25#define MAX31790_REG_PWMOUT(ch) (0x40 + (ch) * 2)
26#define MAX31790_REG_TARGET_COUNT(ch) (0x50 + (ch) * 2)
27
28/* Fan Config register bits */
29#define MAX31790_FAN_CFG_RPM_MODE 0x80
30#define MAX31790_FAN_CFG_CTRL_MON 0x10
31#define MAX31790_FAN_CFG_TACH_INPUT_EN 0x08
32#define MAX31790_FAN_CFG_TACH_INPUT 0x01
33
34/* Fan Dynamics register bits */
35#define MAX31790_FAN_DYN_SR_SHIFT 5
36#define MAX31790_FAN_DYN_SR_MASK 0xE0
37#define SR_FROM_REG(reg) (((reg) & MAX31790_FAN_DYN_SR_MASK) \
38 >> MAX31790_FAN_DYN_SR_SHIFT)
39
40#define FAN_RPM_MIN 120
41#define FAN_RPM_MAX 7864320
42
43#define FAN_COUNT_REG_MAX 0xffe0
44
45#define RPM_FROM_REG(reg, sr) (((reg) >> 4) ? \
46 ((60 * (sr) * 8192) / ((reg) >> 4)) : \
47 FAN_RPM_MAX)
48#define RPM_TO_REG(rpm, sr) ((60 * (sr) * 8192) / ((rpm) * 2))
49
50#define NR_CHANNEL 6
51
52#define PWM_INPUT_SCALE 255
53#define MAX31790_REG_PWMOUT_SCALE 511
54
55/*
56 * Client data (each client gets its own)
57 */
58struct max31790_data {
59 struct i2c_client *client;
60 struct mutex update_lock;
61 bool valid; /* zero until following fields are valid */
62 unsigned long last_updated; /* in jiffies */
63
64 /* register values */
65 u8 fan_config[NR_CHANNEL];
66 u8 fan_dynamics[NR_CHANNEL];
67 u16 fault_status;
68 u16 tach[NR_CHANNEL * 2];
69 u16 pwm[NR_CHANNEL];
70 u16 target_count[NR_CHANNEL];
71};
72
73static struct max31790_data *max31790_update_device(struct device *dev)
74{
75 struct max31790_data *data = dev_get_drvdata(dev);
76 struct i2c_client *client = data->client;
77 struct max31790_data *ret = data;
78 int i;
79 int rv;
80
81 mutex_lock(&data->update_lock);
82
83 if (time_after(jiffies, data->last_updated + HZ) || !data->valid) {
84 rv = i2c_smbus_read_byte_data(client,
85 MAX31790_REG_FAN_FAULT_STATUS1);
86 if (rv < 0)
87 goto abort;
88 data->fault_status |= rv & 0x3F;
89
90 rv = i2c_smbus_read_byte_data(client,
91 MAX31790_REG_FAN_FAULT_STATUS2);
92 if (rv < 0)
93 goto abort;
94 data->fault_status |= (rv & 0x3F) << 6;
95
96 for (i = 0; i < NR_CHANNEL; i++) {
97 rv = i2c_smbus_read_word_swapped(client,
98 MAX31790_REG_TACH_COUNT(i));
99 if (rv < 0)
100 goto abort;
101 data->tach[i] = rv;
102
103 if (data->fan_config[i]
104 & MAX31790_FAN_CFG_TACH_INPUT) {
105 rv = i2c_smbus_read_word_swapped(client,
106 MAX31790_REG_TACH_COUNT(NR_CHANNEL
107 + i));
108 if (rv < 0)
109 goto abort;
110 data->tach[NR_CHANNEL + i] = rv;
111 } else {
112 rv = i2c_smbus_read_word_swapped(client,
113 MAX31790_REG_PWM_DUTY_CYCLE(i));
114 if (rv < 0)
115 goto abort;
116 data->pwm[i] = rv;
117
118 rv = i2c_smbus_read_word_swapped(client,
119 MAX31790_REG_TARGET_COUNT(i));
120 if (rv < 0)
121 goto abort;
122 data->target_count[i] = rv;
123 }
124 }
125
126 data->last_updated = jiffies;
127 data->valid = true;
128 }
129 goto done;
130
131abort:
132 data->valid = false;
133 ret = ERR_PTR(error: rv);
134
135done:
136 mutex_unlock(lock: &data->update_lock);
137
138 return ret;
139}
140
141static const u8 tach_period[8] = { 1, 2, 4, 8, 16, 32, 32, 32 };
142
143static u8 get_tach_period(u8 fan_dynamics)
144{
145 return tach_period[SR_FROM_REG(fan_dynamics)];
146}
147
148static u8 bits_for_tach_period(int rpm)
149{
150 u8 bits;
151
152 if (rpm < 500)
153 bits = 0x0;
154 else if (rpm < 1000)
155 bits = 0x1;
156 else if (rpm < 2000)
157 bits = 0x2;
158 else if (rpm < 4000)
159 bits = 0x3;
160 else if (rpm < 8000)
161 bits = 0x4;
162 else
163 bits = 0x5;
164
165 return bits;
166}
167
168static int max31790_read_fan(struct device *dev, u32 attr, int channel,
169 long *val)
170{
171 struct max31790_data *data = max31790_update_device(dev);
172 int sr, rpm;
173
174 if (IS_ERR(ptr: data))
175 return PTR_ERR(ptr: data);
176
177 switch (attr) {
178 case hwmon_fan_input:
179 sr = get_tach_period(fan_dynamics: data->fan_dynamics[channel % NR_CHANNEL]);
180 if (data->tach[channel] == FAN_COUNT_REG_MAX)
181 rpm = 0;
182 else
183 rpm = RPM_FROM_REG(data->tach[channel], sr);
184 *val = rpm;
185 return 0;
186 case hwmon_fan_target:
187 sr = get_tach_period(fan_dynamics: data->fan_dynamics[channel]);
188 rpm = RPM_FROM_REG(data->target_count[channel], sr);
189 *val = rpm;
190 return 0;
191 case hwmon_fan_fault:
192 mutex_lock(&data->update_lock);
193 *val = !!(data->fault_status & (1 << channel));
194 data->fault_status &= ~(1 << channel);
195 /*
196 * If a fault bit is set, we need to write into one of the fan
197 * configuration registers to clear it. Note that this also
198 * clears the fault for the companion channel if enabled.
199 */
200 if (*val) {
201 int reg = MAX31790_REG_TARGET_COUNT(channel % NR_CHANNEL);
202
203 i2c_smbus_write_byte_data(client: data->client, command: reg,
204 value: data->target_count[channel % NR_CHANNEL] >> 8);
205 }
206 mutex_unlock(lock: &data->update_lock);
207 return 0;
208 case hwmon_fan_enable:
209 *val = !!(data->fan_config[channel] & MAX31790_FAN_CFG_TACH_INPUT_EN);
210 return 0;
211 default:
212 return -EOPNOTSUPP;
213 }
214}
215
216static int max31790_write_fan(struct device *dev, u32 attr, int channel,
217 long val)
218{
219 struct max31790_data *data = dev_get_drvdata(dev);
220 struct i2c_client *client = data->client;
221 int target_count;
222 int err = 0;
223 u8 bits, fan_config;
224 int sr;
225
226 mutex_lock(&data->update_lock);
227
228 switch (attr) {
229 case hwmon_fan_target:
230 val = clamp_val(val, FAN_RPM_MIN, FAN_RPM_MAX);
231 bits = bits_for_tach_period(rpm: val);
232 data->fan_dynamics[channel] =
233 ((data->fan_dynamics[channel] &
234 ~MAX31790_FAN_DYN_SR_MASK) |
235 (bits << MAX31790_FAN_DYN_SR_SHIFT));
236 err = i2c_smbus_write_byte_data(client,
237 MAX31790_REG_FAN_DYNAMICS(channel),
238 value: data->fan_dynamics[channel]);
239 if (err < 0)
240 break;
241
242 sr = get_tach_period(fan_dynamics: data->fan_dynamics[channel]);
243 target_count = RPM_TO_REG(val, sr);
244 target_count = clamp_val(target_count, 0x1, 0x7FF);
245
246 data->target_count[channel] = target_count << 5;
247
248 err = i2c_smbus_write_word_swapped(client,
249 MAX31790_REG_TARGET_COUNT(channel),
250 value: data->target_count[channel]);
251 break;
252 case hwmon_fan_enable:
253 fan_config = data->fan_config[channel];
254 if (val == 0) {
255 fan_config &= ~MAX31790_FAN_CFG_TACH_INPUT_EN;
256 } else if (val == 1) {
257 fan_config |= MAX31790_FAN_CFG_TACH_INPUT_EN;
258 } else {
259 err = -EINVAL;
260 break;
261 }
262 if (fan_config != data->fan_config[channel]) {
263 err = i2c_smbus_write_byte_data(client, MAX31790_REG_FAN_CONFIG(channel),
264 value: fan_config);
265 if (!err)
266 data->fan_config[channel] = fan_config;
267 }
268 break;
269 default:
270 err = -EOPNOTSUPP;
271 break;
272 }
273
274 mutex_unlock(lock: &data->update_lock);
275
276 return err;
277}
278
279static umode_t max31790_fan_is_visible(const void *_data, u32 attr, int channel)
280{
281 const struct max31790_data *data = _data;
282 u8 fan_config = data->fan_config[channel % NR_CHANNEL];
283
284 switch (attr) {
285 case hwmon_fan_input:
286 case hwmon_fan_fault:
287 if (channel < NR_CHANNEL ||
288 (fan_config & MAX31790_FAN_CFG_TACH_INPUT))
289 return 0444;
290 return 0;
291 case hwmon_fan_target:
292 if (channel < NR_CHANNEL &&
293 !(fan_config & MAX31790_FAN_CFG_TACH_INPUT))
294 return 0644;
295 return 0;
296 case hwmon_fan_enable:
297 if (channel < NR_CHANNEL)
298 return 0644;
299 return 0;
300 default:
301 return 0;
302 }
303}
304
305static int max31790_read_pwm(struct device *dev, u32 attr, int channel,
306 long *val)
307{
308 struct max31790_data *data = max31790_update_device(dev);
309 u8 fan_config;
310
311 if (IS_ERR(ptr: data))
312 return PTR_ERR(ptr: data);
313
314 fan_config = data->fan_config[channel];
315
316 switch (attr) {
317 case hwmon_pwm_input:
318 *val = data->pwm[channel] >> 8;
319 return 0;
320 case hwmon_pwm_enable:
321 if (fan_config & MAX31790_FAN_CFG_CTRL_MON)
322 *val = 0;
323 else if (fan_config & MAX31790_FAN_CFG_RPM_MODE)
324 *val = 2;
325 else
326 *val = 1;
327 return 0;
328 default:
329 return -EOPNOTSUPP;
330 }
331}
332
333static int max31790_write_pwm(struct device *dev, u32 attr, int channel,
334 long val)
335{
336 struct max31790_data *data = dev_get_drvdata(dev);
337 struct i2c_client *client = data->client;
338 u8 fan_config;
339 int err = 0;
340
341 mutex_lock(&data->update_lock);
342
343 switch (attr) {
344 case hwmon_pwm_input:
345 if (val < 0 || val > 255) {
346 err = -EINVAL;
347 break;
348 }
349
350 val = DIV_ROUND_CLOSEST(val * MAX31790_REG_PWMOUT_SCALE,
351 PWM_INPUT_SCALE);
352 data->valid = false;
353 err = i2c_smbus_write_word_swapped(client,
354 MAX31790_REG_PWMOUT(channel),
355 value: val << 7);
356 break;
357 case hwmon_pwm_enable:
358 fan_config = data->fan_config[channel];
359 if (val == 0) {
360 fan_config |= MAX31790_FAN_CFG_CTRL_MON;
361 /*
362 * Disable RPM mode; otherwise disabling fan speed
363 * monitoring is not possible.
364 */
365 fan_config &= ~MAX31790_FAN_CFG_RPM_MODE;
366 } else if (val == 1) {
367 fan_config &= ~(MAX31790_FAN_CFG_CTRL_MON | MAX31790_FAN_CFG_RPM_MODE);
368 } else if (val == 2) {
369 fan_config &= ~MAX31790_FAN_CFG_CTRL_MON;
370 /*
371 * The chip sets MAX31790_FAN_CFG_TACH_INPUT_EN on its
372 * own if MAX31790_FAN_CFG_RPM_MODE is set.
373 * Do it here as well to reflect the actual register
374 * value in the cache.
375 */
376 fan_config |= (MAX31790_FAN_CFG_RPM_MODE | MAX31790_FAN_CFG_TACH_INPUT_EN);
377 } else {
378 err = -EINVAL;
379 break;
380 }
381 if (fan_config != data->fan_config[channel]) {
382 err = i2c_smbus_write_byte_data(client, MAX31790_REG_FAN_CONFIG(channel),
383 value: fan_config);
384 if (!err)
385 data->fan_config[channel] = fan_config;
386 }
387 break;
388 default:
389 err = -EOPNOTSUPP;
390 break;
391 }
392
393 mutex_unlock(lock: &data->update_lock);
394
395 return err;
396}
397
398static umode_t max31790_pwm_is_visible(const void *_data, u32 attr, int channel)
399{
400 const struct max31790_data *data = _data;
401 u8 fan_config = data->fan_config[channel];
402
403 switch (attr) {
404 case hwmon_pwm_input:
405 case hwmon_pwm_enable:
406 if (!(fan_config & MAX31790_FAN_CFG_TACH_INPUT))
407 return 0644;
408 return 0;
409 default:
410 return 0;
411 }
412}
413
414static int max31790_read(struct device *dev, enum hwmon_sensor_types type,
415 u32 attr, int channel, long *val)
416{
417 switch (type) {
418 case hwmon_fan:
419 return max31790_read_fan(dev, attr, channel, val);
420 case hwmon_pwm:
421 return max31790_read_pwm(dev, attr, channel, val);
422 default:
423 return -EOPNOTSUPP;
424 }
425}
426
427static int max31790_write(struct device *dev, enum hwmon_sensor_types type,
428 u32 attr, int channel, long val)
429{
430 switch (type) {
431 case hwmon_fan:
432 return max31790_write_fan(dev, attr, channel, val);
433 case hwmon_pwm:
434 return max31790_write_pwm(dev, attr, channel, val);
435 default:
436 return -EOPNOTSUPP;
437 }
438}
439
440static umode_t max31790_is_visible(const void *data,
441 enum hwmon_sensor_types type,
442 u32 attr, int channel)
443{
444 switch (type) {
445 case hwmon_fan:
446 return max31790_fan_is_visible(data: data, attr, channel);
447 case hwmon_pwm:
448 return max31790_pwm_is_visible(data: data, attr, channel);
449 default:
450 return 0;
451 }
452}
453
454static const struct hwmon_channel_info * const max31790_info[] = {
455 HWMON_CHANNEL_INFO(fan,
456 HWMON_F_INPUT | HWMON_F_TARGET | HWMON_F_FAULT | HWMON_F_ENABLE,
457 HWMON_F_INPUT | HWMON_F_TARGET | HWMON_F_FAULT | HWMON_F_ENABLE,
458 HWMON_F_INPUT | HWMON_F_TARGET | HWMON_F_FAULT | HWMON_F_ENABLE,
459 HWMON_F_INPUT | HWMON_F_TARGET | HWMON_F_FAULT | HWMON_F_ENABLE,
460 HWMON_F_INPUT | HWMON_F_TARGET | HWMON_F_FAULT | HWMON_F_ENABLE,
461 HWMON_F_INPUT | HWMON_F_TARGET | HWMON_F_FAULT | HWMON_F_ENABLE,
462 HWMON_F_INPUT | HWMON_F_FAULT,
463 HWMON_F_INPUT | HWMON_F_FAULT,
464 HWMON_F_INPUT | HWMON_F_FAULT,
465 HWMON_F_INPUT | HWMON_F_FAULT,
466 HWMON_F_INPUT | HWMON_F_FAULT,
467 HWMON_F_INPUT | HWMON_F_FAULT),
468 HWMON_CHANNEL_INFO(pwm,
469 HWMON_PWM_INPUT | HWMON_PWM_ENABLE,
470 HWMON_PWM_INPUT | HWMON_PWM_ENABLE,
471 HWMON_PWM_INPUT | HWMON_PWM_ENABLE,
472 HWMON_PWM_INPUT | HWMON_PWM_ENABLE,
473 HWMON_PWM_INPUT | HWMON_PWM_ENABLE,
474 HWMON_PWM_INPUT | HWMON_PWM_ENABLE),
475 NULL
476};
477
478static const struct hwmon_ops max31790_hwmon_ops = {
479 .is_visible = max31790_is_visible,
480 .read = max31790_read,
481 .write = max31790_write,
482};
483
484static const struct hwmon_chip_info max31790_chip_info = {
485 .ops = &max31790_hwmon_ops,
486 .info = max31790_info,
487};
488
489static int max31790_init_client(struct i2c_client *client,
490 struct max31790_data *data)
491{
492 int i, rv;
493
494 for (i = 0; i < NR_CHANNEL; i++) {
495 rv = i2c_smbus_read_byte_data(client,
496 MAX31790_REG_FAN_CONFIG(i));
497 if (rv < 0)
498 return rv;
499 data->fan_config[i] = rv;
500
501 rv = i2c_smbus_read_byte_data(client,
502 MAX31790_REG_FAN_DYNAMICS(i));
503 if (rv < 0)
504 return rv;
505 data->fan_dynamics[i] = rv;
506 }
507
508 return 0;
509}
510
511static int max31790_probe(struct i2c_client *client)
512{
513 struct i2c_adapter *adapter = client->adapter;
514 struct device *dev = &client->dev;
515 struct max31790_data *data;
516 struct device *hwmon_dev;
517 int err;
518
519 if (!i2c_check_functionality(adap: adapter,
520 I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA))
521 return -ENODEV;
522
523 data = devm_kzalloc(dev, size: sizeof(struct max31790_data), GFP_KERNEL);
524 if (!data)
525 return -ENOMEM;
526
527 data->client = client;
528 mutex_init(&data->update_lock);
529
530 /*
531 * Initialize the max31790 chip
532 */
533 err = max31790_init_client(client, data);
534 if (err)
535 return err;
536
537 hwmon_dev = devm_hwmon_device_register_with_info(dev, name: client->name,
538 drvdata: data,
539 info: &max31790_chip_info,
540 NULL);
541
542 return PTR_ERR_OR_ZERO(ptr: hwmon_dev);
543}
544
545static const struct i2c_device_id max31790_id[] = {
546 { "max31790" },
547 { }
548};
549MODULE_DEVICE_TABLE(i2c, max31790_id);
550
551static struct i2c_driver max31790_driver = {
552 .probe = max31790_probe,
553 .driver = {
554 .name = "max31790",
555 },
556 .id_table = max31790_id,
557};
558
559module_i2c_driver(max31790_driver);
560
561MODULE_AUTHOR("Il Han <corone.il.han@gmail.com>");
562MODULE_DESCRIPTION("MAX31790 sensor driver");
563MODULE_LICENSE("GPL");
564

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source code of linux/drivers/hwmon/max31790.c