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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
43/*
44 * Insmod parameters
45 */
46
47/* fan_voltage: 5=5V fan, 12=12V fan, 0=don't change */
48static int fan_voltage;
49/* prescaler: Possible values are 1, 2, 4, 8, 16 or 0 for don't change */
50static int prescaler;
51/* clock: The clock frequency of the chip the driver should assume */
52static int clock = 254000;
53
54module_param(fan_voltage, int, S_IRUGO);
55module_param(prescaler, int, S_IRUGO);
56module_param(clock, int, S_IRUGO);
57
58/*
59 * MAX 6650/6651 registers
60 */
61
62#define MAX6650_REG_SPEED 0x00
63#define MAX6650_REG_CONFIG 0x02
64#define MAX6650_REG_GPIO_DEF 0x04
65#define MAX6650_REG_DAC 0x06
66#define MAX6650_REG_ALARM_EN 0x08
67#define MAX6650_REG_ALARM 0x0A
68#define MAX6650_REG_TACH0 0x0C
69#define MAX6650_REG_TACH1 0x0E
70#define MAX6650_REG_TACH2 0x10
71#define MAX6650_REG_TACH3 0x12
72#define MAX6650_REG_GPIO_STAT 0x14
73#define MAX6650_REG_COUNT 0x16
74
75/*
76 * Config register bits
77 */
78
79#define MAX6650_CFG_V12 0x08
80#define MAX6650_CFG_PRESCALER_MASK 0x07
81#define MAX6650_CFG_PRESCALER_2 0x01
82#define MAX6650_CFG_PRESCALER_4 0x02
83#define MAX6650_CFG_PRESCALER_8 0x03
84#define MAX6650_CFG_PRESCALER_16 0x04
85#define MAX6650_CFG_MODE_MASK 0x30
86#define MAX6650_CFG_MODE_ON 0x00
87#define MAX6650_CFG_MODE_OFF 0x10
88#define MAX6650_CFG_MODE_CLOSED_LOOP 0x20
89#define MAX6650_CFG_MODE_OPEN_LOOP 0x30
90#define MAX6650_COUNT_MASK 0x03
91
92/*
93 * Alarm status register bits
94 */
95
96#define MAX6650_ALRM_MAX 0x01
97#define MAX6650_ALRM_MIN 0x02
98#define MAX6650_ALRM_TACH 0x04
99#define MAX6650_ALRM_GPIO1 0x08
100#define MAX6650_ALRM_GPIO2 0x10
101
102/* Minimum and maximum values of the FAN-RPM */
103#define FAN_RPM_MIN 240
104#define FAN_RPM_MAX 30000
105
106#define DIV_FROM_REG(reg) (1 << (reg & 7))
107
108/*
109 * Client data (each client gets its own)
110 */
111
112struct max6650_data {
113 struct i2c_client *client;
114 const struct attribute_group *groups[3];
115 struct mutex update_lock;
116 int nr_fans;
117 char valid; /* zero until following fields are valid */
118 unsigned long last_updated; /* in jiffies */
119
120 /* register values */
121 u8 speed;
122 u8 config;
123 u8 tach[4];
124 u8 count;
125 u8 dac;
126 u8 alarm;
127};
128
129static const u8 tach_reg[] = {
130 MAX6650_REG_TACH0,
131 MAX6650_REG_TACH1,
132 MAX6650_REG_TACH2,
133 MAX6650_REG_TACH3,
134};
135
136static struct max6650_data *max6650_update_device(struct device *dev)
137{
138 struct max6650_data *data = dev_get_drvdata(dev);
139 struct i2c_client *client = data->client;
140 int i;
141
142 mutex_lock(&data->update_lock);
143
144 if (time_after(jiffies, data->last_updated + HZ) || !data->valid) {
145 data->speed = i2c_smbus_read_byte_data(client,
146 MAX6650_REG_SPEED);
147 data->config = i2c_smbus_read_byte_data(client,
148 MAX6650_REG_CONFIG);
149 for (i = 0; i < data->nr_fans; i++) {
150 data->tach[i] = i2c_smbus_read_byte_data(client,
151 tach_reg[i]);
152 }
153 data->count = i2c_smbus_read_byte_data(client,
154 MAX6650_REG_COUNT);
155 data->dac = i2c_smbus_read_byte_data(client, MAX6650_REG_DAC);
156
157 /*
158 * Alarms are cleared on read in case the condition that
159 * caused the alarm is removed. Keep the value latched here
160 * for providing the register through different alarm files.
161 */
162 data->alarm |= i2c_smbus_read_byte_data(client,
163 MAX6650_REG_ALARM);
164
165 data->last_updated = jiffies;
166 data->valid = 1;
167 }
168
169 mutex_unlock(&data->update_lock);
170
171 return data;
172}
173
174static ssize_t get_fan(struct device *dev, struct device_attribute *devattr,
175 char *buf)
176{
177 struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
178 struct max6650_data *data = max6650_update_device(dev);
179 int rpm;
180
181 /*
182 * Calculation details:
183 *
184 * Each tachometer counts over an interval given by the "count"
185 * register (0.25, 0.5, 1 or 2 seconds). This module assumes
186 * that the fans produce two pulses per revolution (this seems
187 * to be the most common).
188 */
189
190 rpm = ((data->tach[attr->index] * 120) / DIV_FROM_REG(data->count));
191 return sprintf(buf, "%d\n", rpm);
192}
193
194/*
195 * Set the fan speed to the specified RPM (or read back the RPM setting).
196 * This works in closed loop mode only. Use pwm1 for open loop speed setting.
197 *
198 * The MAX6650/1 will automatically control fan speed when in closed loop
199 * mode.
200 *
201 * Assumptions:
202 *
203 * 1) The MAX6650/1 internal 254kHz clock frequency is set correctly. Use
204 * the clock module parameter if you need to fine tune this.
205 *
206 * 2) The prescaler (low three bits of the config register) has already
207 * been set to an appropriate value. Use the prescaler module parameter
208 * if your BIOS doesn't initialize the chip properly.
209 *
210 * The relevant equations are given on pages 21 and 22 of the datasheet.
211 *
212 * From the datasheet, the relevant equation when in regulation is:
213 *
214 * [fCLK / (128 x (KTACH + 1))] = 2 x FanSpeed / KSCALE
215 *
216 * where:
217 *
218 * fCLK is the oscillator frequency (either the 254kHz internal
219 * oscillator or the externally applied clock)
220 *
221 * KTACH is the value in the speed register
222 *
223 * FanSpeed is the speed of the fan in rps
224 *
225 * KSCALE is the prescaler value (1, 2, 4, 8, or 16)
226 *
227 * When reading, we need to solve for FanSpeed. When writing, we need to
228 * solve for KTACH.
229 *
230 * Note: this tachometer is completely separate from the tachometers
231 * used to measure the fan speeds. Only one fan's speed (fan1) is
232 * controlled.
233 */
234
235static ssize_t get_target(struct device *dev, struct device_attribute *devattr,
236 char *buf)
237{
238 struct max6650_data *data = max6650_update_device(dev);
239 int kscale, ktach, rpm;
240
241 /*
242 * Use the datasheet equation:
243 *
244 * FanSpeed = KSCALE x fCLK / [256 x (KTACH + 1)]
245 *
246 * then multiply by 60 to give rpm.
247 */
248
249 kscale = DIV_FROM_REG(data->config);
250 ktach = data->speed;
251 rpm = 60 * kscale * clock / (256 * (ktach + 1));
252 return sprintf(buf, "%d\n", rpm);
253}
254
255static ssize_t set_target(struct device *dev, struct device_attribute *devattr,
256 const char *buf, size_t count)
257{
258 struct max6650_data *data = dev_get_drvdata(dev);
259 struct i2c_client *client = data->client;
260 int kscale, ktach;
261 unsigned long rpm;
262 int err;
263
264 err = kstrtoul(buf, 10, &rpm);
265 if (err)
266 return err;
267
268 rpm = clamp_val(rpm, FAN_RPM_MIN, FAN_RPM_MAX);
269
270 /*
271 * Divide the required speed by 60 to get from rpm to rps, then
272 * use the datasheet equation:
273 *
274 * KTACH = [(fCLK x KSCALE) / (256 x FanSpeed)] - 1
275 */
276
277 mutex_lock(&data->update_lock);
278
279 kscale = DIV_FROM_REG(data->config);
280 ktach = ((clock * kscale) / (256 * rpm / 60)) - 1;
281 if (ktach < 0)
282 ktach = 0;
283 if (ktach > 255)
284 ktach = 255;
285 data->speed = ktach;
286
287 i2c_smbus_write_byte_data(client, MAX6650_REG_SPEED, data->speed);
288
289 mutex_unlock(&data->update_lock);
290
291 return count;
292}
293
294/*
295 * Get/set the fan speed in open loop mode using pwm1 sysfs file.
296 * Speed is given as a relative value from 0 to 255, where 255 is maximum
297 * speed. Note that this is done by writing directly to the chip's DAC,
298 * it won't change the closed loop speed set by fan1_target.
299 * Also note that due to rounding errors it is possible that you don't read
300 * back exactly the value you have set.
301 */
302
303static ssize_t get_pwm(struct device *dev, struct device_attribute *devattr,
304 char *buf)
305{
306 int pwm;
307 struct max6650_data *data = max6650_update_device(dev);
308
309 /*
310 * Useful range for dac is 0-180 for 12V fans and 0-76 for 5V fans.
311 * Lower DAC values mean higher speeds.
312 */
313 if (data->config & MAX6650_CFG_V12)
314 pwm = 255 - (255 * (int)data->dac)/180;
315 else
316 pwm = 255 - (255 * (int)data->dac)/76;
317
318 if (pwm < 0)
319 pwm = 0;
320
321 return sprintf(buf, "%d\n", pwm);
322}
323
324static ssize_t set_pwm(struct device *dev, struct device_attribute *devattr,
325 const char *buf, size_t count)
326{
327 struct max6650_data *data = dev_get_drvdata(dev);
328 struct i2c_client *client = data->client;
329 unsigned long pwm;
330 int err;
331
332 err = kstrtoul(buf, 10, &pwm);
333 if (err)
334 return err;
335
336 pwm = clamp_val(pwm, 0, 255);
337
338 mutex_lock(&data->update_lock);
339
340 if (data->config & MAX6650_CFG_V12)
341 data->dac = 180 - (180 * pwm)/255;
342 else
343 data->dac = 76 - (76 * pwm)/255;
344
345 i2c_smbus_write_byte_data(client, MAX6650_REG_DAC, data->dac);
346
347 mutex_unlock(&data->update_lock);
348
349 return count;
350}
351
352/*
353 * Get/Set controller mode:
354 * Possible values:
355 * 0 = Fan always on
356 * 1 = Open loop, Voltage is set according to speed, not regulated.
357 * 2 = Closed loop, RPM for all fans regulated by fan1 tachometer
358 */
359
360static ssize_t get_enable(struct device *dev, struct device_attribute *devattr,
361 char *buf)
362{
363 struct max6650_data *data = max6650_update_device(dev);
364 int mode = (data->config & MAX6650_CFG_MODE_MASK) >> 4;
365 int sysfs_modes[4] = {0, 1, 2, 1};
366
367 return sprintf(buf, "%d\n", sysfs_modes[mode]);
368}
369
370static ssize_t set_enable(struct device *dev, struct device_attribute *devattr,
371 const char *buf, size_t count)
372{
373 struct max6650_data *data = dev_get_drvdata(dev);
374 struct i2c_client *client = data->client;
375 int max6650_modes[3] = {0, 3, 2};
376 unsigned long mode;
377 int err;
378
379 err = kstrtoul(buf, 10, &mode);
380 if (err)
381 return err;
382
383 if (mode > 2)
384 return -EINVAL;
385
386 mutex_lock(&data->update_lock);
387
388 data->config = i2c_smbus_read_byte_data(client, MAX6650_REG_CONFIG);
389 data->config = (data->config & ~MAX6650_CFG_MODE_MASK)
390 | (max6650_modes[mode] << 4);
391
392 i2c_smbus_write_byte_data(client, MAX6650_REG_CONFIG, data->config);
393
394 mutex_unlock(&data->update_lock);
395
396 return count;
397}
398
399/*
400 * Read/write functions for fan1_div sysfs file. The MAX6650 has no such
401 * divider. We handle this by converting between divider and counttime:
402 *
403 * (counttime == k) <==> (divider == 2^k), k = 0, 1, 2, or 3
404 *
405 * Lower values of k allow to connect a faster fan without the risk of
406 * counter overflow. The price is lower resolution. You can also set counttime
407 * using the module parameter. Note that the module parameter "prescaler" also
408 * influences the behaviour. Unfortunately, there's no sysfs attribute
409 * defined for that. See the data sheet for details.
410 */
411
412static ssize_t get_div(struct device *dev, struct device_attribute *devattr,
413 char *buf)
414{
415 struct max6650_data *data = max6650_update_device(dev);
416
417 return sprintf(buf, "%d\n", DIV_FROM_REG(data->count));
418}
419
420static ssize_t set_div(struct device *dev, struct device_attribute *devattr,
421 const char *buf, size_t count)
422{
423 struct max6650_data *data = dev_get_drvdata(dev);
424 struct i2c_client *client = data->client;
425 unsigned long div;
426 int err;
427
428 err = kstrtoul(buf, 10, &div);
429 if (err)
430 return err;
431
432 mutex_lock(&data->update_lock);
433 switch (div) {
434 case 1:
435 data->count = 0;
436 break;
437 case 2:
438 data->count = 1;
439 break;
440 case 4:
441 data->count = 2;
442 break;
443 case 8:
444 data->count = 3;
445 break;
446 default:
447 mutex_unlock(&data->update_lock);
448 return -EINVAL;
449 }
450
451 i2c_smbus_write_byte_data(client, MAX6650_REG_COUNT, data->count);
452 mutex_unlock(&data->update_lock);
453
454 return count;
455}
456
457/*
458 * Get alarm stati:
459 * Possible values:
460 * 0 = no alarm
461 * 1 = alarm
462 */
463
464static ssize_t get_alarm(struct device *dev, struct device_attribute *devattr,
465 char *buf)
466{
467 struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
468 struct max6650_data *data = max6650_update_device(dev);
469 struct i2c_client *client = data->client;
470 int alarm = 0;
471
472 if (data->alarm & attr->index) {
473 mutex_lock(&data->update_lock);
474 alarm = 1;
475 data->alarm &= ~attr->index;
476 data->alarm |= i2c_smbus_read_byte_data(client,
477 MAX6650_REG_ALARM);
478 mutex_unlock(&data->update_lock);
479 }
480
481 return sprintf(buf, "%d\n", alarm);
482}
483
484static SENSOR_DEVICE_ATTR(fan1_input, S_IRUGO, get_fan, NULL, 0);
485static SENSOR_DEVICE_ATTR(fan2_input, S_IRUGO, get_fan, NULL, 1);
486static SENSOR_DEVICE_ATTR(fan3_input, S_IRUGO, get_fan, NULL, 2);
487static SENSOR_DEVICE_ATTR(fan4_input, S_IRUGO, get_fan, NULL, 3);
488static DEVICE_ATTR(fan1_target, S_IWUSR | S_IRUGO, get_target, set_target);
489static DEVICE_ATTR(fan1_div, S_IWUSR | S_IRUGO, get_div, set_div);
490static DEVICE_ATTR(pwm1_enable, S_IWUSR | S_IRUGO, get_enable, set_enable);
491static DEVICE_ATTR(pwm1, S_IWUSR | S_IRUGO, get_pwm, set_pwm);
492static SENSOR_DEVICE_ATTR(fan1_max_alarm, S_IRUGO, get_alarm, NULL,
493 MAX6650_ALRM_MAX);
494static SENSOR_DEVICE_ATTR(fan1_min_alarm, S_IRUGO, get_alarm, NULL,
495 MAX6650_ALRM_MIN);
496static SENSOR_DEVICE_ATTR(fan1_fault, S_IRUGO, get_alarm, NULL,
497 MAX6650_ALRM_TACH);
498static SENSOR_DEVICE_ATTR(gpio1_alarm, S_IRUGO, get_alarm, NULL,
499 MAX6650_ALRM_GPIO1);
500static SENSOR_DEVICE_ATTR(gpio2_alarm, S_IRUGO, get_alarm, NULL,
501 MAX6650_ALRM_GPIO2);
502
503static umode_t max6650_attrs_visible(struct kobject *kobj, struct attribute *a,
504 int n)
505{
506 struct device *dev = container_of(kobj, struct device, kobj);
507 struct max6650_data *data = dev_get_drvdata(dev);
508 struct i2c_client *client = data->client;
509 u8 alarm_en = i2c_smbus_read_byte_data(client, MAX6650_REG_ALARM_EN);
510 struct device_attribute *devattr;
511
512 /*
513 * Hide the alarms that have not been enabled by the firmware
514 */
515
516 devattr = container_of(a, struct device_attribute, attr);
517 if (devattr == &sensor_dev_attr_fan1_max_alarm.dev_attr
518 || devattr == &sensor_dev_attr_fan1_min_alarm.dev_attr
519 || devattr == &sensor_dev_attr_fan1_fault.dev_attr
520 || devattr == &sensor_dev_attr_gpio1_alarm.dev_attr
521 || devattr == &sensor_dev_attr_gpio2_alarm.dev_attr) {
522 if (!(alarm_en & to_sensor_dev_attr(devattr)->index))
523 return 0;
524 }
525
526 return a->mode;
527}
528
529static struct attribute *max6650_attrs[] = {
530 &sensor_dev_attr_fan1_input.dev_attr.attr,
531 &dev_attr_fan1_target.attr,
532 &dev_attr_fan1_div.attr,
533 &dev_attr_pwm1_enable.attr,
534 &dev_attr_pwm1.attr,
535 &sensor_dev_attr_fan1_max_alarm.dev_attr.attr,
536 &sensor_dev_attr_fan1_min_alarm.dev_attr.attr,
537 &sensor_dev_attr_fan1_fault.dev_attr.attr,
538 &sensor_dev_attr_gpio1_alarm.dev_attr.attr,
539 &sensor_dev_attr_gpio2_alarm.dev_attr.attr,
540 NULL
541};
542
543static const struct attribute_group max6650_group = {
544 .attrs = max6650_attrs,
545 .is_visible = max6650_attrs_visible,
546};
547
548static struct attribute *max6651_attrs[] = {
549 &sensor_dev_attr_fan2_input.dev_attr.attr,
550 &sensor_dev_attr_fan3_input.dev_attr.attr,
551 &sensor_dev_attr_fan4_input.dev_attr.attr,
552 NULL
553};
554
555static const struct attribute_group max6651_group = {
556 .attrs = max6651_attrs,
557};
558
559/*
560 * Real code
561 */
562
563static int max6650_init_client(struct max6650_data *data,
564 struct i2c_client *client)
565{
566 struct device *dev = &client->dev;
567 int config;
568 int err = -EIO;
569
570 config = i2c_smbus_read_byte_data(client, MAX6650_REG_CONFIG);
571
572 if (config < 0) {
573 dev_err(dev, "Error reading config, aborting.\n");
574 return err;
575 }
576
577 switch (fan_voltage) {
578 case 0:
579 break;
580 case 5:
581 config &= ~MAX6650_CFG_V12;
582 break;
583 case 12:
584 config |= MAX6650_CFG_V12;
585 break;
586 default:
587 dev_err(dev, "illegal value for fan_voltage (%d)\n",
588 fan_voltage);
589 }
590
591 dev_info(dev, "Fan voltage is set to %dV.\n",
592 (config & MAX6650_CFG_V12) ? 12 : 5);
593
594 switch (prescaler) {
595 case 0:
596 break;
597 case 1:
598 config &= ~MAX6650_CFG_PRESCALER_MASK;
599 break;
600 case 2:
601 config = (config & ~MAX6650_CFG_PRESCALER_MASK)
602 | MAX6650_CFG_PRESCALER_2;
603 break;
604 case 4:
605 config = (config & ~MAX6650_CFG_PRESCALER_MASK)
606 | MAX6650_CFG_PRESCALER_4;
607 break;
608 case 8:
609 config = (config & ~MAX6650_CFG_PRESCALER_MASK)
610 | MAX6650_CFG_PRESCALER_8;
611 break;
612 case 16:
613 config = (config & ~MAX6650_CFG_PRESCALER_MASK)
614 | MAX6650_CFG_PRESCALER_16;
615 break;
616 default:
617 dev_err(dev, "illegal value for prescaler (%d)\n", prescaler);
618 }
619
620 dev_info(dev, "Prescaler is set to %d.\n",
621 1 << (config & MAX6650_CFG_PRESCALER_MASK));
622
623 /*
624 * If mode is set to "full off", we change it to "open loop" and
625 * set DAC to 255, which has the same effect. We do this because
626 * there's no "full off" mode defined in hwmon specifications.
627 */
628
629 if ((config & MAX6650_CFG_MODE_MASK) == MAX6650_CFG_MODE_OFF) {
630 dev_dbg(dev, "Change mode to open loop, full off.\n");
631 config = (config & ~MAX6650_CFG_MODE_MASK)
632 | MAX6650_CFG_MODE_OPEN_LOOP;
633 if (i2c_smbus_write_byte_data(client, MAX6650_REG_DAC, 255)) {
634 dev_err(dev, "DAC write error, aborting.\n");
635 return err;
636 }
637 }
638
639 if (i2c_smbus_write_byte_data(client, MAX6650_REG_CONFIG, config)) {
640 dev_err(dev, "Config write error, aborting.\n");
641 return err;
642 }
643
644 data->config = config;
645 data->count = i2c_smbus_read_byte_data(client, MAX6650_REG_COUNT);
646
647 return 0;
648}
649
650static int max6650_probe(struct i2c_client *client,
651 const struct i2c_device_id *id)
652{
653 struct device *dev = &client->dev;
654 struct max6650_data *data;
655 struct device *hwmon_dev;
656 int err;
657
658 data = devm_kzalloc(dev, sizeof(struct max6650_data), GFP_KERNEL);
659 if (!data)
660 return -ENOMEM;
661
662 data->client = client;
663 mutex_init(&data->update_lock);
664 data->nr_fans = id->driver_data;
665
666 /*
667 * Initialize the max6650 chip
668 */
669 err = max6650_init_client(data, client);
670 if (err)
671 return err;
672
673 data->groups[0] = &max6650_group;
674 /* 3 additional fan inputs for the MAX6651 */
675 if (data->nr_fans == 4)
676 data->groups[1] = &max6651_group;
677
678 hwmon_dev = devm_hwmon_device_register_with_groups(dev,
679 client->name, data,
680 data->groups);
681 return PTR_ERR_OR_ZERO(hwmon_dev);
682}
683
684static const struct i2c_device_id max6650_id[] = {
685 { "max6650", 1 },
686 { "max6651", 4 },
687 { }
688};
689MODULE_DEVICE_TABLE(i2c, max6650_id);
690
691static struct i2c_driver max6650_driver = {
692 .driver = {
693 .name = "max6650",
694 },
695 .probe = max6650_probe,
696 .id_table = max6650_id,
697};
698
699module_i2c_driver(max6650_driver);
700
701MODULE_AUTHOR("Hans J. Koch");
702MODULE_DESCRIPTION("MAX6650 sensor driver");
703MODULE_LICENSE("GPL");
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
43/*
44 * Insmod parameters
45 */
46
47/* fan_voltage: 5=5V fan, 12=12V fan, 0=don't change */
48static int fan_voltage;
49/* prescaler: Possible values are 1, 2, 4, 8, 16 or 0 for don't change */
50static int prescaler;
51/* clock: The clock frequency of the chip the driver should assume */
52static int clock = 254000;
53
54module_param(fan_voltage, int, S_IRUGO);
55module_param(prescaler, int, S_IRUGO);
56module_param(clock, int, S_IRUGO);
57
58/*
59 * MAX 6650/6651 registers
60 */
61
62#define MAX6650_REG_SPEED 0x00
63#define MAX6650_REG_CONFIG 0x02
64#define MAX6650_REG_GPIO_DEF 0x04
65#define MAX6650_REG_DAC 0x06
66#define MAX6650_REG_ALARM_EN 0x08
67#define MAX6650_REG_ALARM 0x0A
68#define MAX6650_REG_TACH0 0x0C
69#define MAX6650_REG_TACH1 0x0E
70#define MAX6650_REG_TACH2 0x10
71#define MAX6650_REG_TACH3 0x12
72#define MAX6650_REG_GPIO_STAT 0x14
73#define MAX6650_REG_COUNT 0x16
74
75/*
76 * Config register bits
77 */
78
79#define MAX6650_CFG_V12 0x08
80#define MAX6650_CFG_PRESCALER_MASK 0x07
81#define MAX6650_CFG_PRESCALER_2 0x01
82#define MAX6650_CFG_PRESCALER_4 0x02
83#define MAX6650_CFG_PRESCALER_8 0x03
84#define MAX6650_CFG_PRESCALER_16 0x04
85#define MAX6650_CFG_MODE_MASK 0x30
86#define MAX6650_CFG_MODE_ON 0x00
87#define MAX6650_CFG_MODE_OFF 0x10
88#define MAX6650_CFG_MODE_CLOSED_LOOP 0x20
89#define MAX6650_CFG_MODE_OPEN_LOOP 0x30
90#define MAX6650_COUNT_MASK 0x03
91
92/*
93 * Alarm status register bits
94 */
95
96#define MAX6650_ALRM_MAX 0x01
97#define MAX6650_ALRM_MIN 0x02
98#define MAX6650_ALRM_TACH 0x04
99#define MAX6650_ALRM_GPIO1 0x08
100#define MAX6650_ALRM_GPIO2 0x10
101
102/* Minimum and maximum values of the FAN-RPM */
103#define FAN_RPM_MIN 240
104#define FAN_RPM_MAX 30000
105
106#define DIV_FROM_REG(reg) (1 << (reg & 7))
107
108static int max6650_probe(struct i2c_client *client,
109 const struct i2c_device_id *id);
110static int max6650_init_client(struct i2c_client *client);
111static int max6650_remove(struct i2c_client *client);
112static struct max6650_data *max6650_update_device(struct device *dev);
113
114/*
115 * Driver data (common to all clients)
116 */
117
118static const struct i2c_device_id max6650_id[] = {
119 { "max6650", 1 },
120 { "max6651", 4 },
121 { }
122};
123MODULE_DEVICE_TABLE(i2c, max6650_id);
124
125static struct i2c_driver max6650_driver = {
126 .driver = {
127 .name = "max6650",
128 },
129 .probe = max6650_probe,
130 .remove = max6650_remove,
131 .id_table = max6650_id,
132};
133
134/*
135 * Client data (each client gets its own)
136 */
137
138struct max6650_data {
139 struct device *hwmon_dev;
140 struct mutex update_lock;
141 int nr_fans;
142 char valid; /* zero until following fields are valid */
143 unsigned long last_updated; /* in jiffies */
144
145 /* register values */
146 u8 speed;
147 u8 config;
148 u8 tach[4];
149 u8 count;
150 u8 dac;
151 u8 alarm;
152};
153
154static ssize_t get_fan(struct device *dev, struct device_attribute *devattr,
155 char *buf)
156{
157 struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
158 struct max6650_data *data = max6650_update_device(dev);
159 int rpm;
160
161 /*
162 * Calculation details:
163 *
164 * Each tachometer counts over an interval given by the "count"
165 * register (0.25, 0.5, 1 or 2 seconds). This module assumes
166 * that the fans produce two pulses per revolution (this seems
167 * to be the most common).
168 */
169
170 rpm = ((data->tach[attr->index] * 120) / DIV_FROM_REG(data->count));
171 return sprintf(buf, "%d\n", rpm);
172}
173
174/*
175 * Set the fan speed to the specified RPM (or read back the RPM setting).
176 * This works in closed loop mode only. Use pwm1 for open loop speed setting.
177 *
178 * The MAX6650/1 will automatically control fan speed when in closed loop
179 * mode.
180 *
181 * Assumptions:
182 *
183 * 1) The MAX6650/1 internal 254kHz clock frequency is set correctly. Use
184 * the clock module parameter if you need to fine tune this.
185 *
186 * 2) The prescaler (low three bits of the config register) has already
187 * been set to an appropriate value. Use the prescaler module parameter
188 * if your BIOS doesn't initialize the chip properly.
189 *
190 * The relevant equations are given on pages 21 and 22 of the datasheet.
191 *
192 * From the datasheet, the relevant equation when in regulation is:
193 *
194 * [fCLK / (128 x (KTACH + 1))] = 2 x FanSpeed / KSCALE
195 *
196 * where:
197 *
198 * fCLK is the oscillator frequency (either the 254kHz internal
199 * oscillator or the externally applied clock)
200 *
201 * KTACH is the value in the speed register
202 *
203 * FanSpeed is the speed of the fan in rps
204 *
205 * KSCALE is the prescaler value (1, 2, 4, 8, or 16)
206 *
207 * When reading, we need to solve for FanSpeed. When writing, we need to
208 * solve for KTACH.
209 *
210 * Note: this tachometer is completely separate from the tachometers
211 * used to measure the fan speeds. Only one fan's speed (fan1) is
212 * controlled.
213 */
214
215static ssize_t get_target(struct device *dev, struct device_attribute *devattr,
216 char *buf)
217{
218 struct max6650_data *data = max6650_update_device(dev);
219 int kscale, ktach, rpm;
220
221 /*
222 * Use the datasheet equation:
223 *
224 * FanSpeed = KSCALE x fCLK / [256 x (KTACH + 1)]
225 *
226 * then multiply by 60 to give rpm.
227 */
228
229 kscale = DIV_FROM_REG(data->config);
230 ktach = data->speed;
231 rpm = 60 * kscale * clock / (256 * (ktach + 1));
232 return sprintf(buf, "%d\n", rpm);
233}
234
235static ssize_t set_target(struct device *dev, struct device_attribute *devattr,
236 const char *buf, size_t count)
237{
238 struct i2c_client *client = to_i2c_client(dev);
239 struct max6650_data *data = i2c_get_clientdata(client);
240 int kscale, ktach;
241 unsigned long rpm;
242 int err;
243
244 err = kstrtoul(buf, 10, &rpm);
245 if (err)
246 return err;
247
248 rpm = SENSORS_LIMIT(rpm, FAN_RPM_MIN, FAN_RPM_MAX);
249
250 /*
251 * Divide the required speed by 60 to get from rpm to rps, then
252 * use the datasheet equation:
253 *
254 * KTACH = [(fCLK x KSCALE) / (256 x FanSpeed)] - 1
255 */
256
257 mutex_lock(&data->update_lock);
258
259 kscale = DIV_FROM_REG(data->config);
260 ktach = ((clock * kscale) / (256 * rpm / 60)) - 1;
261 if (ktach < 0)
262 ktach = 0;
263 if (ktach > 255)
264 ktach = 255;
265 data->speed = ktach;
266
267 i2c_smbus_write_byte_data(client, MAX6650_REG_SPEED, data->speed);
268
269 mutex_unlock(&data->update_lock);
270
271 return count;
272}
273
274/*
275 * Get/set the fan speed in open loop mode using pwm1 sysfs file.
276 * Speed is given as a relative value from 0 to 255, where 255 is maximum
277 * speed. Note that this is done by writing directly to the chip's DAC,
278 * it won't change the closed loop speed set by fan1_target.
279 * Also note that due to rounding errors it is possible that you don't read
280 * back exactly the value you have set.
281 */
282
283static ssize_t get_pwm(struct device *dev, struct device_attribute *devattr,
284 char *buf)
285{
286 int pwm;
287 struct max6650_data *data = max6650_update_device(dev);
288
289 /*
290 * Useful range for dac is 0-180 for 12V fans and 0-76 for 5V fans.
291 * Lower DAC values mean higher speeds.
292 */
293 if (data->config & MAX6650_CFG_V12)
294 pwm = 255 - (255 * (int)data->dac)/180;
295 else
296 pwm = 255 - (255 * (int)data->dac)/76;
297
298 if (pwm < 0)
299 pwm = 0;
300
301 return sprintf(buf, "%d\n", pwm);
302}
303
304static ssize_t set_pwm(struct device *dev, struct device_attribute *devattr,
305 const char *buf, size_t count)
306{
307 struct i2c_client *client = to_i2c_client(dev);
308 struct max6650_data *data = i2c_get_clientdata(client);
309 unsigned long pwm;
310 int err;
311
312 err = kstrtoul(buf, 10, &pwm);
313 if (err)
314 return err;
315
316 pwm = SENSORS_LIMIT(pwm, 0, 255);
317
318 mutex_lock(&data->update_lock);
319
320 if (data->config & MAX6650_CFG_V12)
321 data->dac = 180 - (180 * pwm)/255;
322 else
323 data->dac = 76 - (76 * pwm)/255;
324
325 i2c_smbus_write_byte_data(client, MAX6650_REG_DAC, data->dac);
326
327 mutex_unlock(&data->update_lock);
328
329 return count;
330}
331
332/*
333 * Get/Set controller mode:
334 * Possible values:
335 * 0 = Fan always on
336 * 1 = Open loop, Voltage is set according to speed, not regulated.
337 * 2 = Closed loop, RPM for all fans regulated by fan1 tachometer
338 */
339
340static ssize_t get_enable(struct device *dev, struct device_attribute *devattr,
341 char *buf)
342{
343 struct max6650_data *data = max6650_update_device(dev);
344 int mode = (data->config & MAX6650_CFG_MODE_MASK) >> 4;
345 int sysfs_modes[4] = {0, 1, 2, 1};
346
347 return sprintf(buf, "%d\n", sysfs_modes[mode]);
348}
349
350static ssize_t set_enable(struct device *dev, struct device_attribute *devattr,
351 const char *buf, size_t count)
352{
353 struct i2c_client *client = to_i2c_client(dev);
354 struct max6650_data *data = i2c_get_clientdata(client);
355 int max6650_modes[3] = {0, 3, 2};
356 unsigned long mode;
357 int err;
358
359 err = kstrtoul(buf, 10, &mode);
360 if (err)
361 return err;
362
363 if (mode > 2)
364 return -EINVAL;
365
366 mutex_lock(&data->update_lock);
367
368 data->config = i2c_smbus_read_byte_data(client, MAX6650_REG_CONFIG);
369 data->config = (data->config & ~MAX6650_CFG_MODE_MASK)
370 | (max6650_modes[mode] << 4);
371
372 i2c_smbus_write_byte_data(client, MAX6650_REG_CONFIG, data->config);
373
374 mutex_unlock(&data->update_lock);
375
376 return count;
377}
378
379/*
380 * Read/write functions for fan1_div sysfs file. The MAX6650 has no such
381 * divider. We handle this by converting between divider and counttime:
382 *
383 * (counttime == k) <==> (divider == 2^k), k = 0, 1, 2, or 3
384 *
385 * Lower values of k allow to connect a faster fan without the risk of
386 * counter overflow. The price is lower resolution. You can also set counttime
387 * using the module parameter. Note that the module parameter "prescaler" also
388 * influences the behaviour. Unfortunately, there's no sysfs attribute
389 * defined for that. See the data sheet for details.
390 */
391
392static ssize_t get_div(struct device *dev, struct device_attribute *devattr,
393 char *buf)
394{
395 struct max6650_data *data = max6650_update_device(dev);
396
397 return sprintf(buf, "%d\n", DIV_FROM_REG(data->count));
398}
399
400static ssize_t set_div(struct device *dev, struct device_attribute *devattr,
401 const char *buf, size_t count)
402{
403 struct i2c_client *client = to_i2c_client(dev);
404 struct max6650_data *data = i2c_get_clientdata(client);
405 unsigned long div;
406 int err;
407
408 err = kstrtoul(buf, 10, &div);
409 if (err)
410 return err;
411
412 mutex_lock(&data->update_lock);
413 switch (div) {
414 case 1:
415 data->count = 0;
416 break;
417 case 2:
418 data->count = 1;
419 break;
420 case 4:
421 data->count = 2;
422 break;
423 case 8:
424 data->count = 3;
425 break;
426 default:
427 mutex_unlock(&data->update_lock);
428 return -EINVAL;
429 }
430
431 i2c_smbus_write_byte_data(client, MAX6650_REG_COUNT, data->count);
432 mutex_unlock(&data->update_lock);
433
434 return count;
435}
436
437/*
438 * Get alarm stati:
439 * Possible values:
440 * 0 = no alarm
441 * 1 = alarm
442 */
443
444static ssize_t get_alarm(struct device *dev, struct device_attribute *devattr,
445 char *buf)
446{
447 struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
448 struct max6650_data *data = max6650_update_device(dev);
449 struct i2c_client *client = to_i2c_client(dev);
450 int alarm = 0;
451
452 if (data->alarm & attr->index) {
453 mutex_lock(&data->update_lock);
454 alarm = 1;
455 data->alarm &= ~attr->index;
456 data->alarm |= i2c_smbus_read_byte_data(client,
457 MAX6650_REG_ALARM);
458 mutex_unlock(&data->update_lock);
459 }
460
461 return sprintf(buf, "%d\n", alarm);
462}
463
464static SENSOR_DEVICE_ATTR(fan1_input, S_IRUGO, get_fan, NULL, 0);
465static SENSOR_DEVICE_ATTR(fan2_input, S_IRUGO, get_fan, NULL, 1);
466static SENSOR_DEVICE_ATTR(fan3_input, S_IRUGO, get_fan, NULL, 2);
467static SENSOR_DEVICE_ATTR(fan4_input, S_IRUGO, get_fan, NULL, 3);
468static DEVICE_ATTR(fan1_target, S_IWUSR | S_IRUGO, get_target, set_target);
469static DEVICE_ATTR(fan1_div, S_IWUSR | S_IRUGO, get_div, set_div);
470static DEVICE_ATTR(pwm1_enable, S_IWUSR | S_IRUGO, get_enable, set_enable);
471static DEVICE_ATTR(pwm1, S_IWUSR | S_IRUGO, get_pwm, set_pwm);
472static SENSOR_DEVICE_ATTR(fan1_max_alarm, S_IRUGO, get_alarm, NULL,
473 MAX6650_ALRM_MAX);
474static SENSOR_DEVICE_ATTR(fan1_min_alarm, S_IRUGO, get_alarm, NULL,
475 MAX6650_ALRM_MIN);
476static SENSOR_DEVICE_ATTR(fan1_fault, S_IRUGO, get_alarm, NULL,
477 MAX6650_ALRM_TACH);
478static SENSOR_DEVICE_ATTR(gpio1_alarm, S_IRUGO, get_alarm, NULL,
479 MAX6650_ALRM_GPIO1);
480static SENSOR_DEVICE_ATTR(gpio2_alarm, S_IRUGO, get_alarm, NULL,
481 MAX6650_ALRM_GPIO2);
482
483static umode_t max6650_attrs_visible(struct kobject *kobj, struct attribute *a,
484 int n)
485{
486 struct device *dev = container_of(kobj, struct device, kobj);
487 struct i2c_client *client = to_i2c_client(dev);
488 u8 alarm_en = i2c_smbus_read_byte_data(client, MAX6650_REG_ALARM_EN);
489 struct device_attribute *devattr;
490
491 /*
492 * Hide the alarms that have not been enabled by the firmware
493 */
494
495 devattr = container_of(a, struct device_attribute, attr);
496 if (devattr == &sensor_dev_attr_fan1_max_alarm.dev_attr
497 || devattr == &sensor_dev_attr_fan1_min_alarm.dev_attr
498 || devattr == &sensor_dev_attr_fan1_fault.dev_attr
499 || devattr == &sensor_dev_attr_gpio1_alarm.dev_attr
500 || devattr == &sensor_dev_attr_gpio2_alarm.dev_attr) {
501 if (!(alarm_en & to_sensor_dev_attr(devattr)->index))
502 return 0;
503 }
504
505 return a->mode;
506}
507
508static struct attribute *max6650_attrs[] = {
509 &sensor_dev_attr_fan1_input.dev_attr.attr,
510 &dev_attr_fan1_target.attr,
511 &dev_attr_fan1_div.attr,
512 &dev_attr_pwm1_enable.attr,
513 &dev_attr_pwm1.attr,
514 &sensor_dev_attr_fan1_max_alarm.dev_attr.attr,
515 &sensor_dev_attr_fan1_min_alarm.dev_attr.attr,
516 &sensor_dev_attr_fan1_fault.dev_attr.attr,
517 &sensor_dev_attr_gpio1_alarm.dev_attr.attr,
518 &sensor_dev_attr_gpio2_alarm.dev_attr.attr,
519 NULL
520};
521
522static struct attribute_group max6650_attr_grp = {
523 .attrs = max6650_attrs,
524 .is_visible = max6650_attrs_visible,
525};
526
527static struct attribute *max6651_attrs[] = {
528 &sensor_dev_attr_fan2_input.dev_attr.attr,
529 &sensor_dev_attr_fan3_input.dev_attr.attr,
530 &sensor_dev_attr_fan4_input.dev_attr.attr,
531 NULL
532};
533
534static const struct attribute_group max6651_attr_grp = {
535 .attrs = max6651_attrs,
536};
537
538/*
539 * Real code
540 */
541
542static int max6650_probe(struct i2c_client *client,
543 const struct i2c_device_id *id)
544{
545 struct max6650_data *data;
546 int err;
547
548 data = kzalloc(sizeof(struct max6650_data), GFP_KERNEL);
549 if (!data) {
550 dev_err(&client->dev, "out of memory.\n");
551 return -ENOMEM;
552 }
553
554 i2c_set_clientdata(client, data);
555 mutex_init(&data->update_lock);
556 data->nr_fans = id->driver_data;
557
558 /*
559 * Initialize the max6650 chip
560 */
561 err = max6650_init_client(client);
562 if (err)
563 goto err_free;
564
565 err = sysfs_create_group(&client->dev.kobj, &max6650_attr_grp);
566 if (err)
567 goto err_free;
568 /* 3 additional fan inputs for the MAX6651 */
569 if (data->nr_fans == 4) {
570 err = sysfs_create_group(&client->dev.kobj, &max6651_attr_grp);
571 if (err)
572 goto err_remove;
573 }
574
575 data->hwmon_dev = hwmon_device_register(&client->dev);
576 if (!IS_ERR(data->hwmon_dev))
577 return 0;
578
579 err = PTR_ERR(data->hwmon_dev);
580 dev_err(&client->dev, "error registering hwmon device.\n");
581 if (data->nr_fans == 4)
582 sysfs_remove_group(&client->dev.kobj, &max6651_attr_grp);
583err_remove:
584 sysfs_remove_group(&client->dev.kobj, &max6650_attr_grp);
585err_free:
586 kfree(data);
587 return err;
588}
589
590static int max6650_remove(struct i2c_client *client)
591{
592 struct max6650_data *data = i2c_get_clientdata(client);
593
594 hwmon_device_unregister(data->hwmon_dev);
595 if (data->nr_fans == 4)
596 sysfs_remove_group(&client->dev.kobj, &max6651_attr_grp);
597 sysfs_remove_group(&client->dev.kobj, &max6650_attr_grp);
598 kfree(data);
599 return 0;
600}
601
602static int max6650_init_client(struct i2c_client *client)
603{
604 struct max6650_data *data = i2c_get_clientdata(client);
605 int config;
606 int err = -EIO;
607
608 config = i2c_smbus_read_byte_data(client, MAX6650_REG_CONFIG);
609
610 if (config < 0) {
611 dev_err(&client->dev, "Error reading config, aborting.\n");
612 return err;
613 }
614
615 switch (fan_voltage) {
616 case 0:
617 break;
618 case 5:
619 config &= ~MAX6650_CFG_V12;
620 break;
621 case 12:
622 config |= MAX6650_CFG_V12;
623 break;
624 default:
625 dev_err(&client->dev, "illegal value for fan_voltage (%d)\n",
626 fan_voltage);
627 }
628
629 dev_info(&client->dev, "Fan voltage is set to %dV.\n",
630 (config & MAX6650_CFG_V12) ? 12 : 5);
631
632 switch (prescaler) {
633 case 0:
634 break;
635 case 1:
636 config &= ~MAX6650_CFG_PRESCALER_MASK;
637 break;
638 case 2:
639 config = (config & ~MAX6650_CFG_PRESCALER_MASK)
640 | MAX6650_CFG_PRESCALER_2;
641 break;
642 case 4:
643 config = (config & ~MAX6650_CFG_PRESCALER_MASK)
644 | MAX6650_CFG_PRESCALER_4;
645 break;
646 case 8:
647 config = (config & ~MAX6650_CFG_PRESCALER_MASK)
648 | MAX6650_CFG_PRESCALER_8;
649 break;
650 case 16:
651 config = (config & ~MAX6650_CFG_PRESCALER_MASK)
652 | MAX6650_CFG_PRESCALER_16;
653 break;
654 default:
655 dev_err(&client->dev, "illegal value for prescaler (%d)\n",
656 prescaler);
657 }
658
659 dev_info(&client->dev, "Prescaler is set to %d.\n",
660 1 << (config & MAX6650_CFG_PRESCALER_MASK));
661
662 /*
663 * If mode is set to "full off", we change it to "open loop" and
664 * set DAC to 255, which has the same effect. We do this because
665 * there's no "full off" mode defined in hwmon specifcations.
666 */
667
668 if ((config & MAX6650_CFG_MODE_MASK) == MAX6650_CFG_MODE_OFF) {
669 dev_dbg(&client->dev, "Change mode to open loop, full off.\n");
670 config = (config & ~MAX6650_CFG_MODE_MASK)
671 | MAX6650_CFG_MODE_OPEN_LOOP;
672 if (i2c_smbus_write_byte_data(client, MAX6650_REG_DAC, 255)) {
673 dev_err(&client->dev, "DAC write error, aborting.\n");
674 return err;
675 }
676 }
677
678 if (i2c_smbus_write_byte_data(client, MAX6650_REG_CONFIG, config)) {
679 dev_err(&client->dev, "Config write error, aborting.\n");
680 return err;
681 }
682
683 data->config = config;
684 data->count = i2c_smbus_read_byte_data(client, MAX6650_REG_COUNT);
685
686 return 0;
687}
688
689static const u8 tach_reg[] = {
690 MAX6650_REG_TACH0,
691 MAX6650_REG_TACH1,
692 MAX6650_REG_TACH2,
693 MAX6650_REG_TACH3,
694};
695
696static struct max6650_data *max6650_update_device(struct device *dev)
697{
698 int i;
699 struct i2c_client *client = to_i2c_client(dev);
700 struct max6650_data *data = i2c_get_clientdata(client);
701
702 mutex_lock(&data->update_lock);
703
704 if (time_after(jiffies, data->last_updated + HZ) || !data->valid) {
705 data->speed = i2c_smbus_read_byte_data(client,
706 MAX6650_REG_SPEED);
707 data->config = i2c_smbus_read_byte_data(client,
708 MAX6650_REG_CONFIG);
709 for (i = 0; i < data->nr_fans; i++) {
710 data->tach[i] = i2c_smbus_read_byte_data(client,
711 tach_reg[i]);
712 }
713 data->count = i2c_smbus_read_byte_data(client,
714 MAX6650_REG_COUNT);
715 data->dac = i2c_smbus_read_byte_data(client, MAX6650_REG_DAC);
716
717 /*
718 * Alarms are cleared on read in case the condition that
719 * caused the alarm is removed. Keep the value latched here
720 * for providing the register through different alarm files.
721 */
722 data->alarm |= i2c_smbus_read_byte_data(client,
723 MAX6650_REG_ALARM);
724
725 data->last_updated = jiffies;
726 data->valid = 1;
727 }
728
729 mutex_unlock(&data->update_lock);
730
731 return data;
732}
733
734module_i2c_driver(max6650_driver);
735
736MODULE_AUTHOR("Hans J. Koch");
737MODULE_DESCRIPTION("MAX6650 sensor driver");
738MODULE_LICENSE("GPL");