1 /*
2 * max6650.c - Part of lm_sensors, Linux kernel modules for hardware
3 * monitoring.
4 *
5 * (C) 2007 by Hans J. Koch <hjk@hansjkoch.de>
6 *
7 * based on code written by John Morris <john.morris@spirentcom.com>
8 * Copyright (c) 2003 Spirent Communications
9 * and Claus Gindhart <claus.gindhart@kontron.com>
10 *
11 * This module has only been tested with the MAX6650 chip. It should
12 * also work with the MAX6651. It does not distinguish max6650 and max6651
13 * chips.
14 *
15 * The datasheet was last seen at:
16 *
17 * http://pdfserv.maxim-ic.com/en/ds/MAX6650-MAX6651.pdf
18 *
19 * This program is free software; you can redistribute it and/or modify
20 * it under the terms of the GNU General Public License as published by
21 * the Free Software Foundation; either version 2 of the License, or
22 * (at your option) any later version.
23 *
24 * This program is distributed in the hope that it will be useful,
25 * but WITHOUT ANY WARRANTY; without even the implied warranty of
26 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
27 * GNU General Public License for more details.
28 *
29 * You should have received a copy of the GNU General Public License
30 * along with this program; if not, write to the Free Software
31 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
32 */
33
34 #include <linux/module.h>
35 #include <linux/init.h>
36 #include <linux/slab.h>
37 #include <linux/jiffies.h>
38 #include <linux/i2c.h>
39 #include <linux/hwmon.h>
40 #include <linux/hwmon-sysfs.h>
41 #include <linux/err.h>
42 #include <linux/of_device.h>
43
44 /*
45 * Insmod parameters
46 */
47
48 /* fan_voltage: 5=5V fan, 12=12V fan, 0=don't change */
49 static int fan_voltage;
50 /* prescaler: Possible values are 1, 2, 4, 8, 16 or 0 for don't change */
51 static int prescaler;
52 /* clock: The clock frequency of the chip (max6651 can be clocked externally) */
53 static int clock = 254000;
54
55 module_param(fan_voltage, int, S_IRUGO);
56 module_param(prescaler, int, S_IRUGO);
57 module_param(clock, int, S_IRUGO);
58
59 /*
60 * MAX 6650/6651 registers
61 */
62
63 #define MAX6650_REG_SPEED 0x00
64 #define MAX6650_REG_CONFIG 0x02
65 #define MAX6650_REG_GPIO_DEF 0x04
66 #define MAX6650_REG_DAC 0x06
67 #define MAX6650_REG_ALARM_EN 0x08
68 #define MAX6650_REG_ALARM 0x0A
69 #define MAX6650_REG_TACH0 0x0C
70 #define MAX6650_REG_TACH1 0x0E
71 #define MAX6650_REG_TACH2 0x10
72 #define MAX6650_REG_TACH3 0x12
73 #define MAX6650_REG_GPIO_STAT 0x14
74 #define MAX6650_REG_COUNT 0x16
75
76 /*
77 * Config register bits
78 */
79
80 #define MAX6650_CFG_V12 0x08
81 #define MAX6650_CFG_PRESCALER_MASK 0x07
82 #define MAX6650_CFG_PRESCALER_2 0x01
83 #define MAX6650_CFG_PRESCALER_4 0x02
84 #define MAX6650_CFG_PRESCALER_8 0x03
85 #define MAX6650_CFG_PRESCALER_16 0x04
86 #define MAX6650_CFG_MODE_MASK 0x30
87 #define MAX6650_CFG_MODE_ON 0x00
88 #define MAX6650_CFG_MODE_OFF 0x10
89 #define MAX6650_CFG_MODE_CLOSED_LOOP 0x20
90 #define MAX6650_CFG_MODE_OPEN_LOOP 0x30
91 #define MAX6650_COUNT_MASK 0x03
92
93 /*
94 * Alarm status register bits
95 */
96
97 #define MAX6650_ALRM_MAX 0x01
98 #define MAX6650_ALRM_MIN 0x02
99 #define MAX6650_ALRM_TACH 0x04
100 #define MAX6650_ALRM_GPIO1 0x08
101 #define MAX6650_ALRM_GPIO2 0x10
102
103 /* Minimum and maximum values of the FAN-RPM */
104 #define FAN_RPM_MIN 240
105 #define FAN_RPM_MAX 30000
106
107 #define DIV_FROM_REG(reg) (1 << (reg & 7))
108
109 /*
110 * Client data (each client gets its own)
111 */
112
113 struct max6650_data {
114 struct i2c_client *client;
115 const struct attribute_group *groups[3];
116 struct mutex update_lock;
117 int nr_fans;
118 char valid; /* zero until following fields are valid */
119 unsigned long last_updated; /* in jiffies */
120
121 /* register values */
122 u8 speed;
123 u8 config;
124 u8 tach[4];
125 u8 count;
126 u8 dac;
127 u8 alarm;
128 };
129
130 static const u8 tach_reg[] = {
131 MAX6650_REG_TACH0,
132 MAX6650_REG_TACH1,
133 MAX6650_REG_TACH2,
134 MAX6650_REG_TACH3,
135 };
136
137 static const struct of_device_id max6650_dt_match[] = {
138 {
139 .compatible = "maxim,max6650",
140 .data = (void *)1
141 },
142 {
143 .compatible = "maxim,max6651",
144 .data = (void *)4
145 },
146 { },
147 };
148 MODULE_DEVICE_TABLE(of, max6650_dt_match);
149
max6650_update_device(struct device * dev)150 static struct max6650_data *max6650_update_device(struct device *dev)
151 {
152 struct max6650_data *data = dev_get_drvdata(dev);
153 struct i2c_client *client = data->client;
154 int i;
155
156 mutex_lock(&data->update_lock);
157
158 if (time_after(jiffies, data->last_updated + HZ) || !data->valid) {
159 data->speed = i2c_smbus_read_byte_data(client,
160 MAX6650_REG_SPEED);
161 data->config = i2c_smbus_read_byte_data(client,
162 MAX6650_REG_CONFIG);
163 for (i = 0; i < data->nr_fans; i++) {
164 data->tach[i] = i2c_smbus_read_byte_data(client,
165 tach_reg[i]);
166 }
167 data->count = i2c_smbus_read_byte_data(client,
168 MAX6650_REG_COUNT);
169 data->dac = i2c_smbus_read_byte_data(client, MAX6650_REG_DAC);
170
171 /*
172 * Alarms are cleared on read in case the condition that
173 * caused the alarm is removed. Keep the value latched here
174 * for providing the register through different alarm files.
175 */
176 data->alarm |= i2c_smbus_read_byte_data(client,
177 MAX6650_REG_ALARM);
178
179 data->last_updated = jiffies;
180 data->valid = 1;
181 }
182
183 mutex_unlock(&data->update_lock);
184
185 return data;
186 }
187
188 /*
189 * Change the operating mode of the chip (if needed).
190 * mode is one of the MAX6650_CFG_MODE_* values.
191 */
max6650_set_operating_mode(struct max6650_data * data,u8 mode)192 static int max6650_set_operating_mode(struct max6650_data *data, u8 mode)
193 {
194 int result;
195 u8 config = data->config;
196
197 if (mode == (config & MAX6650_CFG_MODE_MASK))
198 return 0;
199
200 config = (config & ~MAX6650_CFG_MODE_MASK) | mode;
201
202 result = i2c_smbus_write_byte_data(data->client, MAX6650_REG_CONFIG,
203 config);
204 if (result < 0)
205 return result;
206
207 data->config = config;
208
209 return 0;
210 }
211
get_fan(struct device * dev,struct device_attribute * devattr,char * buf)212 static ssize_t get_fan(struct device *dev, struct device_attribute *devattr,
213 char *buf)
214 {
215 struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
216 struct max6650_data *data = max6650_update_device(dev);
217 int rpm;
218
219 /*
220 * Calculation details:
221 *
222 * Each tachometer counts over an interval given by the "count"
223 * register (0.25, 0.5, 1 or 2 seconds). This module assumes
224 * that the fans produce two pulses per revolution (this seems
225 * to be the most common).
226 */
227
228 rpm = ((data->tach[attr->index] * 120) / DIV_FROM_REG(data->count));
229 return sprintf(buf, "%d\n", rpm);
230 }
231
232 /*
233 * Set the fan speed to the specified RPM (or read back the RPM setting).
234 * This works in closed loop mode only. Use pwm1 for open loop speed setting.
235 *
236 * The MAX6650/1 will automatically control fan speed when in closed loop
237 * mode.
238 *
239 * Assumptions:
240 *
241 * 1) The MAX6650/1 internal 254kHz clock frequency is set correctly. Use
242 * the clock module parameter if you need to fine tune this.
243 *
244 * 2) The prescaler (low three bits of the config register) has already
245 * been set to an appropriate value. Use the prescaler module parameter
246 * if your BIOS doesn't initialize the chip properly.
247 *
248 * The relevant equations are given on pages 21 and 22 of the datasheet.
249 *
250 * From the datasheet, the relevant equation when in regulation is:
251 *
252 * [fCLK / (128 x (KTACH + 1))] = 2 x FanSpeed / KSCALE
253 *
254 * where:
255 *
256 * fCLK is the oscillator frequency (either the 254kHz internal
257 * oscillator or the externally applied clock)
258 *
259 * KTACH is the value in the speed register
260 *
261 * FanSpeed is the speed of the fan in rps
262 *
263 * KSCALE is the prescaler value (1, 2, 4, 8, or 16)
264 *
265 * When reading, we need to solve for FanSpeed. When writing, we need to
266 * solve for KTACH.
267 *
268 * Note: this tachometer is completely separate from the tachometers
269 * used to measure the fan speeds. Only one fan's speed (fan1) is
270 * controlled.
271 */
272
fan1_target_show(struct device * dev,struct device_attribute * devattr,char * buf)273 static ssize_t fan1_target_show(struct device *dev,
274 struct device_attribute *devattr, char *buf)
275 {
276 struct max6650_data *data = max6650_update_device(dev);
277 int kscale, ktach, rpm;
278
279 /*
280 * Use the datasheet equation:
281 *
282 * FanSpeed = KSCALE x fCLK / [256 x (KTACH + 1)]
283 *
284 * then multiply by 60 to give rpm.
285 */
286
287 kscale = DIV_FROM_REG(data->config);
288 ktach = data->speed;
289 rpm = 60 * kscale * clock / (256 * (ktach + 1));
290 return sprintf(buf, "%d\n", rpm);
291 }
292
max6650_set_target(struct max6650_data * data,unsigned long rpm)293 static int max6650_set_target(struct max6650_data *data, unsigned long rpm)
294 {
295 int kscale, ktach;
296
297 if (rpm == 0)
298 return max6650_set_operating_mode(data, MAX6650_CFG_MODE_OFF);
299
300 rpm = clamp_val(rpm, FAN_RPM_MIN, FAN_RPM_MAX);
301
302 /*
303 * Divide the required speed by 60 to get from rpm to rps, then
304 * use the datasheet equation:
305 *
306 * KTACH = [(fCLK x KSCALE) / (256 x FanSpeed)] - 1
307 */
308
309 kscale = DIV_FROM_REG(data->config);
310 ktach = ((clock * kscale) / (256 * rpm / 60)) - 1;
311 if (ktach < 0)
312 ktach = 0;
313 if (ktach > 255)
314 ktach = 255;
315 data->speed = ktach;
316
317 return i2c_smbus_write_byte_data(data->client, MAX6650_REG_SPEED,
318 data->speed);
319 }
320
fan1_target_store(struct device * dev,struct device_attribute * devattr,const char * buf,size_t count)321 static ssize_t fan1_target_store(struct device *dev,
322 struct device_attribute *devattr,
323 const char *buf, size_t count)
324 {
325 struct max6650_data *data = dev_get_drvdata(dev);
326 unsigned long rpm;
327 int err;
328
329 err = kstrtoul(buf, 10, &rpm);
330 if (err)
331 return err;
332
333 mutex_lock(&data->update_lock);
334
335 err = max6650_set_target(data, rpm);
336
337 mutex_unlock(&data->update_lock);
338
339 if (err < 0)
340 return err;
341
342 return count;
343 }
344
345 /*
346 * Get/set the fan speed in open loop mode using pwm1 sysfs file.
347 * Speed is given as a relative value from 0 to 255, where 255 is maximum
348 * speed. Note that this is done by writing directly to the chip's DAC,
349 * it won't change the closed loop speed set by fan1_target.
350 * Also note that due to rounding errors it is possible that you don't read
351 * back exactly the value you have set.
352 */
353
pwm1_show(struct device * dev,struct device_attribute * devattr,char * buf)354 static ssize_t pwm1_show(struct device *dev, struct device_attribute *devattr,
355 char *buf)
356 {
357 int pwm;
358 struct max6650_data *data = max6650_update_device(dev);
359
360 /*
361 * Useful range for dac is 0-180 for 12V fans and 0-76 for 5V fans.
362 * Lower DAC values mean higher speeds.
363 */
364 if (data->config & MAX6650_CFG_V12)
365 pwm = 255 - (255 * (int)data->dac)/180;
366 else
367 pwm = 255 - (255 * (int)data->dac)/76;
368
369 if (pwm < 0)
370 pwm = 0;
371
372 return sprintf(buf, "%d\n", pwm);
373 }
374
pwm1_store(struct device * dev,struct device_attribute * devattr,const char * buf,size_t count)375 static ssize_t pwm1_store(struct device *dev,
376 struct device_attribute *devattr, const char *buf,
377 size_t count)
378 {
379 struct max6650_data *data = dev_get_drvdata(dev);
380 struct i2c_client *client = data->client;
381 unsigned long pwm;
382 int err;
383
384 err = kstrtoul(buf, 10, &pwm);
385 if (err)
386 return err;
387
388 pwm = clamp_val(pwm, 0, 255);
389
390 mutex_lock(&data->update_lock);
391
392 if (data->config & MAX6650_CFG_V12)
393 data->dac = 180 - (180 * pwm)/255;
394 else
395 data->dac = 76 - (76 * pwm)/255;
396 err = i2c_smbus_write_byte_data(client, MAX6650_REG_DAC, data->dac);
397
398 mutex_unlock(&data->update_lock);
399
400 return err < 0 ? err : count;
401 }
402
403 /*
404 * Get/Set controller mode:
405 * Possible values:
406 * 0 = Fan always on
407 * 1 = Open loop, Voltage is set according to speed, not regulated.
408 * 2 = Closed loop, RPM for all fans regulated by fan1 tachometer
409 * 3 = Fan off
410 */
pwm1_enable_show(struct device * dev,struct device_attribute * devattr,char * buf)411 static ssize_t pwm1_enable_show(struct device *dev,
412 struct device_attribute *devattr, char *buf)
413 {
414 struct max6650_data *data = max6650_update_device(dev);
415 int mode = (data->config & MAX6650_CFG_MODE_MASK) >> 4;
416 int sysfs_modes[4] = {0, 3, 2, 1};
417
418 return sprintf(buf, "%d\n", sysfs_modes[mode]);
419 }
420
pwm1_enable_store(struct device * dev,struct device_attribute * devattr,const char * buf,size_t count)421 static ssize_t pwm1_enable_store(struct device *dev,
422 struct device_attribute *devattr,
423 const char *buf, size_t count)
424 {
425 struct max6650_data *data = dev_get_drvdata(dev);
426 unsigned long mode;
427 int err;
428 const u8 max6650_modes[] = {
429 MAX6650_CFG_MODE_ON,
430 MAX6650_CFG_MODE_OPEN_LOOP,
431 MAX6650_CFG_MODE_CLOSED_LOOP,
432 MAX6650_CFG_MODE_OFF,
433 };
434
435 err = kstrtoul(buf, 10, &mode);
436 if (err)
437 return err;
438
439 if (mode >= ARRAY_SIZE(max6650_modes))
440 return -EINVAL;
441
442 mutex_lock(&data->update_lock);
443
444 max6650_set_operating_mode(data, max6650_modes[mode]);
445
446 mutex_unlock(&data->update_lock);
447
448 return count;
449 }
450
451 /*
452 * Read/write functions for fan1_div sysfs file. The MAX6650 has no such
453 * divider. We handle this by converting between divider and counttime:
454 *
455 * (counttime == k) <==> (divider == 2^k), k = 0, 1, 2, or 3
456 *
457 * Lower values of k allow to connect a faster fan without the risk of
458 * counter overflow. The price is lower resolution. You can also set counttime
459 * using the module parameter. Note that the module parameter "prescaler" also
460 * influences the behaviour. Unfortunately, there's no sysfs attribute
461 * defined for that. See the data sheet for details.
462 */
463
fan1_div_show(struct device * dev,struct device_attribute * devattr,char * buf)464 static ssize_t fan1_div_show(struct device *dev,
465 struct device_attribute *devattr, char *buf)
466 {
467 struct max6650_data *data = max6650_update_device(dev);
468
469 return sprintf(buf, "%d\n", DIV_FROM_REG(data->count));
470 }
471
fan1_div_store(struct device * dev,struct device_attribute * devattr,const char * buf,size_t count)472 static ssize_t fan1_div_store(struct device *dev,
473 struct device_attribute *devattr,
474 const char *buf, size_t count)
475 {
476 struct max6650_data *data = dev_get_drvdata(dev);
477 struct i2c_client *client = data->client;
478 unsigned long div;
479 int err;
480
481 err = kstrtoul(buf, 10, &div);
482 if (err)
483 return err;
484
485 mutex_lock(&data->update_lock);
486 switch (div) {
487 case 1:
488 data->count = 0;
489 break;
490 case 2:
491 data->count = 1;
492 break;
493 case 4:
494 data->count = 2;
495 break;
496 case 8:
497 data->count = 3;
498 break;
499 default:
500 mutex_unlock(&data->update_lock);
501 return -EINVAL;
502 }
503
504 i2c_smbus_write_byte_data(client, MAX6650_REG_COUNT, data->count);
505 mutex_unlock(&data->update_lock);
506
507 return count;
508 }
509
510 /*
511 * Get alarm stati:
512 * Possible values:
513 * 0 = no alarm
514 * 1 = alarm
515 */
516
get_alarm(struct device * dev,struct device_attribute * devattr,char * buf)517 static ssize_t get_alarm(struct device *dev, struct device_attribute *devattr,
518 char *buf)
519 {
520 struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
521 struct max6650_data *data = max6650_update_device(dev);
522 struct i2c_client *client = data->client;
523 int alarm = 0;
524
525 if (data->alarm & attr->index) {
526 mutex_lock(&data->update_lock);
527 alarm = 1;
528 data->alarm &= ~attr->index;
529 data->alarm |= i2c_smbus_read_byte_data(client,
530 MAX6650_REG_ALARM);
531 mutex_unlock(&data->update_lock);
532 }
533
534 return sprintf(buf, "%d\n", alarm);
535 }
536
537 static SENSOR_DEVICE_ATTR(fan1_input, S_IRUGO, get_fan, NULL, 0);
538 static SENSOR_DEVICE_ATTR(fan2_input, S_IRUGO, get_fan, NULL, 1);
539 static SENSOR_DEVICE_ATTR(fan3_input, S_IRUGO, get_fan, NULL, 2);
540 static SENSOR_DEVICE_ATTR(fan4_input, S_IRUGO, get_fan, NULL, 3);
541 static DEVICE_ATTR_RW(fan1_target);
542 static DEVICE_ATTR_RW(fan1_div);
543 static DEVICE_ATTR_RW(pwm1_enable);
544 static DEVICE_ATTR_RW(pwm1);
545 static SENSOR_DEVICE_ATTR(fan1_max_alarm, S_IRUGO, get_alarm, NULL,
546 MAX6650_ALRM_MAX);
547 static SENSOR_DEVICE_ATTR(fan1_min_alarm, S_IRUGO, get_alarm, NULL,
548 MAX6650_ALRM_MIN);
549 static SENSOR_DEVICE_ATTR(fan1_fault, S_IRUGO, get_alarm, NULL,
550 MAX6650_ALRM_TACH);
551 static SENSOR_DEVICE_ATTR(gpio1_alarm, S_IRUGO, get_alarm, NULL,
552 MAX6650_ALRM_GPIO1);
553 static SENSOR_DEVICE_ATTR(gpio2_alarm, S_IRUGO, get_alarm, NULL,
554 MAX6650_ALRM_GPIO2);
555
max6650_attrs_visible(struct kobject * kobj,struct attribute * a,int n)556 static umode_t max6650_attrs_visible(struct kobject *kobj, struct attribute *a,
557 int n)
558 {
559 struct device *dev = container_of(kobj, struct device, kobj);
560 struct max6650_data *data = dev_get_drvdata(dev);
561 struct i2c_client *client = data->client;
562 u8 alarm_en = i2c_smbus_read_byte_data(client, MAX6650_REG_ALARM_EN);
563 struct device_attribute *devattr;
564
565 /*
566 * Hide the alarms that have not been enabled by the firmware
567 */
568
569 devattr = container_of(a, struct device_attribute, attr);
570 if (devattr == &sensor_dev_attr_fan1_max_alarm.dev_attr
571 || devattr == &sensor_dev_attr_fan1_min_alarm.dev_attr
572 || devattr == &sensor_dev_attr_fan1_fault.dev_attr
573 || devattr == &sensor_dev_attr_gpio1_alarm.dev_attr
574 || devattr == &sensor_dev_attr_gpio2_alarm.dev_attr) {
575 if (!(alarm_en & to_sensor_dev_attr(devattr)->index))
576 return 0;
577 }
578
579 return a->mode;
580 }
581
582 static struct attribute *max6650_attrs[] = {
583 &sensor_dev_attr_fan1_input.dev_attr.attr,
584 &dev_attr_fan1_target.attr,
585 &dev_attr_fan1_div.attr,
586 &dev_attr_pwm1_enable.attr,
587 &dev_attr_pwm1.attr,
588 &sensor_dev_attr_fan1_max_alarm.dev_attr.attr,
589 &sensor_dev_attr_fan1_min_alarm.dev_attr.attr,
590 &sensor_dev_attr_fan1_fault.dev_attr.attr,
591 &sensor_dev_attr_gpio1_alarm.dev_attr.attr,
592 &sensor_dev_attr_gpio2_alarm.dev_attr.attr,
593 NULL
594 };
595
596 static const struct attribute_group max6650_group = {
597 .attrs = max6650_attrs,
598 .is_visible = max6650_attrs_visible,
599 };
600
601 static struct attribute *max6651_attrs[] = {
602 &sensor_dev_attr_fan2_input.dev_attr.attr,
603 &sensor_dev_attr_fan3_input.dev_attr.attr,
604 &sensor_dev_attr_fan4_input.dev_attr.attr,
605 NULL
606 };
607
608 static const struct attribute_group max6651_group = {
609 .attrs = max6651_attrs,
610 };
611
612 /*
613 * Real code
614 */
615
max6650_init_client(struct max6650_data * data,struct i2c_client * client)616 static int max6650_init_client(struct max6650_data *data,
617 struct i2c_client *client)
618 {
619 struct device *dev = &client->dev;
620 int config;
621 int err = -EIO;
622 u32 voltage;
623 u32 prescale;
624 u32 target_rpm;
625
626 if (of_property_read_u32(dev->of_node, "maxim,fan-microvolt",
627 &voltage))
628 voltage = fan_voltage;
629 else
630 voltage /= 1000000; /* Microvolts to volts */
631 if (of_property_read_u32(dev->of_node, "maxim,fan-prescale",
632 &prescale))
633 prescale = prescaler;
634
635 config = i2c_smbus_read_byte_data(client, MAX6650_REG_CONFIG);
636
637 if (config < 0) {
638 dev_err(dev, "Error reading config, aborting.\n");
639 return err;
640 }
641
642 switch (voltage) {
643 case 0:
644 break;
645 case 5:
646 config &= ~MAX6650_CFG_V12;
647 break;
648 case 12:
649 config |= MAX6650_CFG_V12;
650 break;
651 default:
652 dev_err(dev, "illegal value for fan_voltage (%d)\n", voltage);
653 }
654
655 switch (prescale) {
656 case 0:
657 break;
658 case 1:
659 config &= ~MAX6650_CFG_PRESCALER_MASK;
660 break;
661 case 2:
662 config = (config & ~MAX6650_CFG_PRESCALER_MASK)
663 | MAX6650_CFG_PRESCALER_2;
664 break;
665 case 4:
666 config = (config & ~MAX6650_CFG_PRESCALER_MASK)
667 | MAX6650_CFG_PRESCALER_4;
668 break;
669 case 8:
670 config = (config & ~MAX6650_CFG_PRESCALER_MASK)
671 | MAX6650_CFG_PRESCALER_8;
672 break;
673 case 16:
674 config = (config & ~MAX6650_CFG_PRESCALER_MASK)
675 | MAX6650_CFG_PRESCALER_16;
676 break;
677 default:
678 dev_err(dev, "illegal value for prescaler (%d)\n", prescale);
679 }
680
681 dev_info(dev, "Fan voltage: %dV, prescaler: %d.\n",
682 (config & MAX6650_CFG_V12) ? 12 : 5,
683 1 << (config & MAX6650_CFG_PRESCALER_MASK));
684
685 if (i2c_smbus_write_byte_data(client, MAX6650_REG_CONFIG, config)) {
686 dev_err(dev, "Config write error, aborting.\n");
687 return err;
688 }
689
690 data->config = config;
691 data->count = i2c_smbus_read_byte_data(client, MAX6650_REG_COUNT);
692
693 if (!of_property_read_u32(client->dev.of_node, "maxim,fan-target-rpm",
694 &target_rpm)) {
695 max6650_set_target(data, target_rpm);
696 max6650_set_operating_mode(data, MAX6650_CFG_MODE_CLOSED_LOOP);
697 }
698
699 return 0;
700 }
701
max6650_probe(struct i2c_client * client,const struct i2c_device_id * id)702 static int max6650_probe(struct i2c_client *client,
703 const struct i2c_device_id *id)
704 {
705 struct device *dev = &client->dev;
706 const struct of_device_id *of_id =
707 of_match_device(of_match_ptr(max6650_dt_match), dev);
708 struct max6650_data *data;
709 struct device *hwmon_dev;
710 int err;
711
712 data = devm_kzalloc(dev, sizeof(struct max6650_data), GFP_KERNEL);
713 if (!data)
714 return -ENOMEM;
715
716 data->client = client;
717 mutex_init(&data->update_lock);
718 data->nr_fans = of_id ? (int)(uintptr_t)of_id->data : id->driver_data;
719
720 /*
721 * Initialize the max6650 chip
722 */
723 err = max6650_init_client(data, client);
724 if (err)
725 return err;
726
727 data->groups[0] = &max6650_group;
728 /* 3 additional fan inputs for the MAX6651 */
729 if (data->nr_fans == 4)
730 data->groups[1] = &max6651_group;
731
732 hwmon_dev = devm_hwmon_device_register_with_groups(dev,
733 client->name, data,
734 data->groups);
735 return PTR_ERR_OR_ZERO(hwmon_dev);
736 }
737
738 static const struct i2c_device_id max6650_id[] = {
739 { "max6650", 1 },
740 { "max6651", 4 },
741 { }
742 };
743 MODULE_DEVICE_TABLE(i2c, max6650_id);
744
745 static struct i2c_driver max6650_driver = {
746 .driver = {
747 .name = "max6650",
748 .of_match_table = of_match_ptr(max6650_dt_match),
749 },
750 .probe = max6650_probe,
751 .id_table = max6650_id,
752 };
753
754 module_i2c_driver(max6650_driver);
755
756 MODULE_AUTHOR("Hans J. Koch");
757 MODULE_DESCRIPTION("MAX6650 sensor driver");
758 MODULE_LICENSE("GPL");
759
