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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/*
53 * Client data (each client gets its own)
54 */
55struct max31790_data {
56 struct i2c_client *client;
57 struct mutex update_lock;
58 bool valid; /* zero until following fields are valid */
59 unsigned long last_updated; /* in jiffies */
60
61 /* register values */
62 u8 fan_config[NR_CHANNEL];
63 u8 fan_dynamics[NR_CHANNEL];
64 u16 fault_status;
65 u16 tach[NR_CHANNEL * 2];
66 u16 pwm[NR_CHANNEL];
67 u16 target_count[NR_CHANNEL];
68};
69
70static struct max31790_data *max31790_update_device(struct device *dev)
71{
72 struct max31790_data *data = dev_get_drvdata(dev);
73 struct i2c_client *client = data->client;
74 struct max31790_data *ret = data;
75 int i;
76 int rv;
77
78 mutex_lock(&data->update_lock);
79
80 if (time_after(jiffies, data->last_updated + HZ) || !data->valid) {
81 rv = i2c_smbus_read_byte_data(client,
82 MAX31790_REG_FAN_FAULT_STATUS1);
83 if (rv < 0)
84 goto abort;
85 data->fault_status |= rv & 0x3F;
86
87 rv = i2c_smbus_read_byte_data(client,
88 MAX31790_REG_FAN_FAULT_STATUS2);
89 if (rv < 0)
90 goto abort;
91 data->fault_status |= (rv & 0x3F) << 6;
92
93 for (i = 0; i < NR_CHANNEL; i++) {
94 rv = i2c_smbus_read_word_swapped(client,
95 MAX31790_REG_TACH_COUNT(i));
96 if (rv < 0)
97 goto abort;
98 data->tach[i] = rv;
99
100 if (data->fan_config[i]
101 & MAX31790_FAN_CFG_TACH_INPUT) {
102 rv = i2c_smbus_read_word_swapped(client,
103 MAX31790_REG_TACH_COUNT(NR_CHANNEL
104 + i));
105 if (rv < 0)
106 goto abort;
107 data->tach[NR_CHANNEL + i] = rv;
108 } else {
109 rv = i2c_smbus_read_word_swapped(client,
110 MAX31790_REG_PWM_DUTY_CYCLE(i));
111 if (rv < 0)
112 goto abort;
113 data->pwm[i] = rv;
114
115 rv = i2c_smbus_read_word_swapped(client,
116 MAX31790_REG_TARGET_COUNT(i));
117 if (rv < 0)
118 goto abort;
119 data->target_count[i] = rv;
120 }
121 }
122
123 data->last_updated = jiffies;
124 data->valid = true;
125 }
126 goto done;
127
128abort:
129 data->valid = false;
130 ret = ERR_PTR(rv);
131
132done:
133 mutex_unlock(&data->update_lock);
134
135 return ret;
136}
137
138static const u8 tach_period[8] = { 1, 2, 4, 8, 16, 32, 32, 32 };
139
140static u8 get_tach_period(u8 fan_dynamics)
141{
142 return tach_period[SR_FROM_REG(fan_dynamics)];
143}
144
145static u8 bits_for_tach_period(int rpm)
146{
147 u8 bits;
148
149 if (rpm < 500)
150 bits = 0x0;
151 else if (rpm < 1000)
152 bits = 0x1;
153 else if (rpm < 2000)
154 bits = 0x2;
155 else if (rpm < 4000)
156 bits = 0x3;
157 else if (rpm < 8000)
158 bits = 0x4;
159 else
160 bits = 0x5;
161
162 return bits;
163}
164
165static int max31790_read_fan(struct device *dev, u32 attr, int channel,
166 long *val)
167{
168 struct max31790_data *data = max31790_update_device(dev);
169 int sr, rpm;
170
171 if (IS_ERR(data))
172 return PTR_ERR(data);
173
174 switch (attr) {
175 case hwmon_fan_input:
176 sr = get_tach_period(data->fan_dynamics[channel % NR_CHANNEL]);
177 if (data->tach[channel] == FAN_COUNT_REG_MAX)
178 rpm = 0;
179 else
180 rpm = RPM_FROM_REG(data->tach[channel], sr);
181 *val = rpm;
182 return 0;
183 case hwmon_fan_target:
184 sr = get_tach_period(data->fan_dynamics[channel]);
185 rpm = RPM_FROM_REG(data->target_count[channel], sr);
186 *val = rpm;
187 return 0;
188 case hwmon_fan_fault:
189 mutex_lock(&data->update_lock);
190 *val = !!(data->fault_status & (1 << channel));
191 data->fault_status &= ~(1 << channel);
192 /*
193 * If a fault bit is set, we need to write into one of the fan
194 * configuration registers to clear it. Note that this also
195 * clears the fault for the companion channel if enabled.
196 */
197 if (*val) {
198 int reg = MAX31790_REG_TARGET_COUNT(channel % NR_CHANNEL);
199
200 i2c_smbus_write_byte_data(data->client, reg,
201 data->target_count[channel % NR_CHANNEL] >> 8);
202 }
203 mutex_unlock(&data->update_lock);
204 return 0;
205 case hwmon_fan_enable:
206 *val = !!(data->fan_config[channel] & MAX31790_FAN_CFG_TACH_INPUT_EN);
207 return 0;
208 default:
209 return -EOPNOTSUPP;
210 }
211}
212
213static int max31790_write_fan(struct device *dev, u32 attr, int channel,
214 long val)
215{
216 struct max31790_data *data = dev_get_drvdata(dev);
217 struct i2c_client *client = data->client;
218 int target_count;
219 int err = 0;
220 u8 bits, fan_config;
221 int sr;
222
223 mutex_lock(&data->update_lock);
224
225 switch (attr) {
226 case hwmon_fan_target:
227 val = clamp_val(val, FAN_RPM_MIN, FAN_RPM_MAX);
228 bits = bits_for_tach_period(val);
229 data->fan_dynamics[channel] =
230 ((data->fan_dynamics[channel] &
231 ~MAX31790_FAN_DYN_SR_MASK) |
232 (bits << MAX31790_FAN_DYN_SR_SHIFT));
233 err = i2c_smbus_write_byte_data(client,
234 MAX31790_REG_FAN_DYNAMICS(channel),
235 data->fan_dynamics[channel]);
236 if (err < 0)
237 break;
238
239 sr = get_tach_period(data->fan_dynamics[channel]);
240 target_count = RPM_TO_REG(val, sr);
241 target_count = clamp_val(target_count, 0x1, 0x7FF);
242
243 data->target_count[channel] = target_count << 5;
244
245 err = i2c_smbus_write_word_swapped(client,
246 MAX31790_REG_TARGET_COUNT(channel),
247 data->target_count[channel]);
248 break;
249 case hwmon_fan_enable:
250 fan_config = data->fan_config[channel];
251 if (val == 0) {
252 fan_config &= ~MAX31790_FAN_CFG_TACH_INPUT_EN;
253 } else if (val == 1) {
254 fan_config |= MAX31790_FAN_CFG_TACH_INPUT_EN;
255 } else {
256 err = -EINVAL;
257 break;
258 }
259 if (fan_config != data->fan_config[channel]) {
260 err = i2c_smbus_write_byte_data(client, MAX31790_REG_FAN_CONFIG(channel),
261 fan_config);
262 if (!err)
263 data->fan_config[channel] = fan_config;
264 }
265 break;
266 default:
267 err = -EOPNOTSUPP;
268 break;
269 }
270
271 mutex_unlock(&data->update_lock);
272
273 return err;
274}
275
276static umode_t max31790_fan_is_visible(const void *_data, u32 attr, int channel)
277{
278 const struct max31790_data *data = _data;
279 u8 fan_config = data->fan_config[channel % NR_CHANNEL];
280
281 switch (attr) {
282 case hwmon_fan_input:
283 case hwmon_fan_fault:
284 if (channel < NR_CHANNEL ||
285 (fan_config & MAX31790_FAN_CFG_TACH_INPUT))
286 return 0444;
287 return 0;
288 case hwmon_fan_target:
289 if (channel < NR_CHANNEL &&
290 !(fan_config & MAX31790_FAN_CFG_TACH_INPUT))
291 return 0644;
292 return 0;
293 case hwmon_fan_enable:
294 if (channel < NR_CHANNEL)
295 return 0644;
296 return 0;
297 default:
298 return 0;
299 }
300}
301
302static int max31790_read_pwm(struct device *dev, u32 attr, int channel,
303 long *val)
304{
305 struct max31790_data *data = max31790_update_device(dev);
306 u8 fan_config;
307
308 if (IS_ERR(data))
309 return PTR_ERR(data);
310
311 fan_config = data->fan_config[channel];
312
313 switch (attr) {
314 case hwmon_pwm_input:
315 *val = data->pwm[channel] >> 8;
316 return 0;
317 case hwmon_pwm_enable:
318 if (fan_config & MAX31790_FAN_CFG_CTRL_MON)
319 *val = 0;
320 else if (fan_config & MAX31790_FAN_CFG_RPM_MODE)
321 *val = 2;
322 else
323 *val = 1;
324 return 0;
325 default:
326 return -EOPNOTSUPP;
327 }
328}
329
330static int max31790_write_pwm(struct device *dev, u32 attr, int channel,
331 long val)
332{
333 struct max31790_data *data = dev_get_drvdata(dev);
334 struct i2c_client *client = data->client;
335 u8 fan_config;
336 int err = 0;
337
338 mutex_lock(&data->update_lock);
339
340 switch (attr) {
341 case hwmon_pwm_input:
342 if (val < 0 || val > 255) {
343 err = -EINVAL;
344 break;
345 }
346 data->valid = false;
347 err = i2c_smbus_write_word_swapped(client,
348 MAX31790_REG_PWMOUT(channel),
349 val << 8);
350 break;
351 case hwmon_pwm_enable:
352 fan_config = data->fan_config[channel];
353 if (val == 0) {
354 fan_config |= MAX31790_FAN_CFG_CTRL_MON;
355 /*
356 * Disable RPM mode; otherwise disabling fan speed
357 * monitoring is not possible.
358 */
359 fan_config &= ~MAX31790_FAN_CFG_RPM_MODE;
360 } else if (val == 1) {
361 fan_config &= ~(MAX31790_FAN_CFG_CTRL_MON | MAX31790_FAN_CFG_RPM_MODE);
362 } else if (val == 2) {
363 fan_config &= ~MAX31790_FAN_CFG_CTRL_MON;
364 /*
365 * The chip sets MAX31790_FAN_CFG_TACH_INPUT_EN on its
366 * own if MAX31790_FAN_CFG_RPM_MODE is set.
367 * Do it here as well to reflect the actual register
368 * value in the cache.
369 */
370 fan_config |= (MAX31790_FAN_CFG_RPM_MODE | MAX31790_FAN_CFG_TACH_INPUT_EN);
371 } else {
372 err = -EINVAL;
373 break;
374 }
375 if (fan_config != data->fan_config[channel]) {
376 err = i2c_smbus_write_byte_data(client, MAX31790_REG_FAN_CONFIG(channel),
377 fan_config);
378 if (!err)
379 data->fan_config[channel] = fan_config;
380 }
381 break;
382 default:
383 err = -EOPNOTSUPP;
384 break;
385 }
386
387 mutex_unlock(&data->update_lock);
388
389 return err;
390}
391
392static umode_t max31790_pwm_is_visible(const void *_data, u32 attr, int channel)
393{
394 const struct max31790_data *data = _data;
395 u8 fan_config = data->fan_config[channel];
396
397 switch (attr) {
398 case hwmon_pwm_input:
399 case hwmon_pwm_enable:
400 if (!(fan_config & MAX31790_FAN_CFG_TACH_INPUT))
401 return 0644;
402 return 0;
403 default:
404 return 0;
405 }
406}
407
408static int max31790_read(struct device *dev, enum hwmon_sensor_types type,
409 u32 attr, int channel, long *val)
410{
411 switch (type) {
412 case hwmon_fan:
413 return max31790_read_fan(dev, attr, channel, val);
414 case hwmon_pwm:
415 return max31790_read_pwm(dev, attr, channel, val);
416 default:
417 return -EOPNOTSUPP;
418 }
419}
420
421static int max31790_write(struct device *dev, enum hwmon_sensor_types type,
422 u32 attr, int channel, long val)
423{
424 switch (type) {
425 case hwmon_fan:
426 return max31790_write_fan(dev, attr, channel, val);
427 case hwmon_pwm:
428 return max31790_write_pwm(dev, attr, channel, val);
429 default:
430 return -EOPNOTSUPP;
431 }
432}
433
434static umode_t max31790_is_visible(const void *data,
435 enum hwmon_sensor_types type,
436 u32 attr, int channel)
437{
438 switch (type) {
439 case hwmon_fan:
440 return max31790_fan_is_visible(data, attr, channel);
441 case hwmon_pwm:
442 return max31790_pwm_is_visible(data, attr, channel);
443 default:
444 return 0;
445 }
446}
447
448static const struct hwmon_channel_info *max31790_info[] = {
449 HWMON_CHANNEL_INFO(fan,
450 HWMON_F_INPUT | HWMON_F_TARGET | HWMON_F_FAULT | HWMON_F_ENABLE,
451 HWMON_F_INPUT | HWMON_F_TARGET | HWMON_F_FAULT | HWMON_F_ENABLE,
452 HWMON_F_INPUT | HWMON_F_TARGET | HWMON_F_FAULT | HWMON_F_ENABLE,
453 HWMON_F_INPUT | HWMON_F_TARGET | HWMON_F_FAULT | HWMON_F_ENABLE,
454 HWMON_F_INPUT | HWMON_F_TARGET | HWMON_F_FAULT | HWMON_F_ENABLE,
455 HWMON_F_INPUT | HWMON_F_TARGET | HWMON_F_FAULT | HWMON_F_ENABLE,
456 HWMON_F_INPUT | HWMON_F_FAULT,
457 HWMON_F_INPUT | HWMON_F_FAULT,
458 HWMON_F_INPUT | HWMON_F_FAULT,
459 HWMON_F_INPUT | HWMON_F_FAULT,
460 HWMON_F_INPUT | HWMON_F_FAULT,
461 HWMON_F_INPUT | HWMON_F_FAULT),
462 HWMON_CHANNEL_INFO(pwm,
463 HWMON_PWM_INPUT | HWMON_PWM_ENABLE,
464 HWMON_PWM_INPUT | HWMON_PWM_ENABLE,
465 HWMON_PWM_INPUT | HWMON_PWM_ENABLE,
466 HWMON_PWM_INPUT | HWMON_PWM_ENABLE,
467 HWMON_PWM_INPUT | HWMON_PWM_ENABLE,
468 HWMON_PWM_INPUT | HWMON_PWM_ENABLE),
469 NULL
470};
471
472static const struct hwmon_ops max31790_hwmon_ops = {
473 .is_visible = max31790_is_visible,
474 .read = max31790_read,
475 .write = max31790_write,
476};
477
478static const struct hwmon_chip_info max31790_chip_info = {
479 .ops = &max31790_hwmon_ops,
480 .info = max31790_info,
481};
482
483static int max31790_init_client(struct i2c_client *client,
484 struct max31790_data *data)
485{
486 int i, rv;
487
488 for (i = 0; i < NR_CHANNEL; i++) {
489 rv = i2c_smbus_read_byte_data(client,
490 MAX31790_REG_FAN_CONFIG(i));
491 if (rv < 0)
492 return rv;
493 data->fan_config[i] = rv;
494
495 rv = i2c_smbus_read_byte_data(client,
496 MAX31790_REG_FAN_DYNAMICS(i));
497 if (rv < 0)
498 return rv;
499 data->fan_dynamics[i] = rv;
500 }
501
502 return 0;
503}
504
505static int max31790_probe(struct i2c_client *client)
506{
507 struct i2c_adapter *adapter = client->adapter;
508 struct device *dev = &client->dev;
509 struct max31790_data *data;
510 struct device *hwmon_dev;
511 int err;
512
513 if (!i2c_check_functionality(adapter,
514 I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA))
515 return -ENODEV;
516
517 data = devm_kzalloc(dev, sizeof(struct max31790_data), GFP_KERNEL);
518 if (!data)
519 return -ENOMEM;
520
521 data->client = client;
522 mutex_init(&data->update_lock);
523
524 /*
525 * Initialize the max31790 chip
526 */
527 err = max31790_init_client(client, data);
528 if (err)
529 return err;
530
531 hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name,
532 data,
533 &max31790_chip_info,
534 NULL);
535
536 return PTR_ERR_OR_ZERO(hwmon_dev);
537}
538
539static const struct i2c_device_id max31790_id[] = {
540 { "max31790", 0 },
541 { }
542};
543MODULE_DEVICE_TABLE(i2c, max31790_id);
544
545static struct i2c_driver max31790_driver = {
546 .class = I2C_CLASS_HWMON,
547 .probe_new = max31790_probe,
548 .driver = {
549 .name = "max31790",
550 },
551 .id_table = max31790_id,
552};
553
554module_i2c_driver(max31790_driver);
555
556MODULE_AUTHOR("Il Han <corone.il.han@gmail.com>");
557MODULE_DESCRIPTION("MAX31790 sensor driver");
558MODULE_LICENSE("GPL");