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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
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{
140 struct device *hwmon_dev;
141 struct mutex update_lock;
142 int nr_fans;
143 char valid; /* zero until following fields are valid */
144 unsigned long last_updated; /* in jiffies */
145
146 /* register values */
147 u8 speed;
148 u8 config;
149 u8 tach[4];
150 u8 count;
151 u8 dac;
152 u8 alarm;
153};
154
155static ssize_t get_fan(struct device *dev, struct device_attribute *devattr,
156 char *buf)
157{
158 struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
159 struct max6650_data *data = max6650_update_device(dev);
160 int rpm;
161
162 /*
163 * Calculation details:
164 *
165 * Each tachometer counts over an interval given by the "count"
166 * register (0.25, 0.5, 1 or 2 seconds). This module assumes
167 * that the fans produce two pulses per revolution (this seems
168 * to be the most common).
169 */
170
171 rpm = ((data->tach[attr->index] * 120) / DIV_FROM_REG(data->count));
172 return sprintf(buf, "%d\n", rpm);
173}
174
175/*
176 * Set the fan speed to the specified RPM (or read back the RPM setting).
177 * This works in closed loop mode only. Use pwm1 for open loop speed setting.
178 *
179 * The MAX6650/1 will automatically control fan speed when in closed loop
180 * mode.
181 *
182 * Assumptions:
183 *
184 * 1) The MAX6650/1 internal 254kHz clock frequency is set correctly. Use
185 * the clock module parameter if you need to fine tune this.
186 *
187 * 2) The prescaler (low three bits of the config register) has already
188 * been set to an appropriate value. Use the prescaler module parameter
189 * if your BIOS doesn't initialize the chip properly.
190 *
191 * The relevant equations are given on pages 21 and 22 of the datasheet.
192 *
193 * From the datasheet, the relevant equation when in regulation is:
194 *
195 * [fCLK / (128 x (KTACH + 1))] = 2 x FanSpeed / KSCALE
196 *
197 * where:
198 *
199 * fCLK is the oscillator frequency (either the 254kHz internal
200 * oscillator or the externally applied clock)
201 *
202 * KTACH is the value in the speed register
203 *
204 * FanSpeed is the speed of the fan in rps
205 *
206 * KSCALE is the prescaler value (1, 2, 4, 8, or 16)
207 *
208 * When reading, we need to solve for FanSpeed. When writing, we need to
209 * solve for KTACH.
210 *
211 * Note: this tachometer is completely separate from the tachometers
212 * used to measure the fan speeds. Only one fan's speed (fan1) is
213 * controlled.
214 */
215
216static ssize_t get_target(struct device *dev, struct device_attribute *devattr,
217 char *buf)
218{
219 struct max6650_data *data = max6650_update_device(dev);
220 int kscale, ktach, rpm;
221
222 /*
223 * Use the datasheet equation:
224 *
225 * FanSpeed = KSCALE x fCLK / [256 x (KTACH + 1)]
226 *
227 * then multiply by 60 to give rpm.
228 */
229
230 kscale = DIV_FROM_REG(data->config);
231 ktach = data->speed;
232 rpm = 60 * kscale * clock / (256 * (ktach + 1));
233 return sprintf(buf, "%d\n", rpm);
234}
235
236static ssize_t set_target(struct device *dev, struct device_attribute *devattr,
237 const char *buf, size_t count)
238{
239 struct i2c_client *client = to_i2c_client(dev);
240 struct max6650_data *data = i2c_get_clientdata(client);
241 int rpm = simple_strtoul(buf, NULL, 10);
242 int kscale, ktach;
243
244 rpm = SENSORS_LIMIT(rpm, FAN_RPM_MIN, FAN_RPM_MAX);
245
246 /*
247 * Divide the required speed by 60 to get from rpm to rps, then
248 * use the datasheet equation:
249 *
250 * KTACH = [(fCLK x KSCALE) / (256 x FanSpeed)] - 1
251 */
252
253 mutex_lock(&data->update_lock);
254
255 kscale = DIV_FROM_REG(data->config);
256 ktach = ((clock * kscale) / (256 * rpm / 60)) - 1;
257 if (ktach < 0)
258 ktach = 0;
259 if (ktach > 255)
260 ktach = 255;
261 data->speed = ktach;
262
263 i2c_smbus_write_byte_data(client, MAX6650_REG_SPEED, data->speed);
264
265 mutex_unlock(&data->update_lock);
266
267 return count;
268}
269
270/*
271 * Get/set the fan speed in open loop mode using pwm1 sysfs file.
272 * Speed is given as a relative value from 0 to 255, where 255 is maximum
273 * speed. Note that this is done by writing directly to the chip's DAC,
274 * it won't change the closed loop speed set by fan1_target.
275 * Also note that due to rounding errors it is possible that you don't read
276 * back exactly the value you have set.
277 */
278
279static ssize_t get_pwm(struct device *dev, struct device_attribute *devattr,
280 char *buf)
281{
282 int pwm;
283 struct max6650_data *data = max6650_update_device(dev);
284
285 /* Useful range for dac is 0-180 for 12V fans and 0-76 for 5V fans.
286 Lower DAC values mean higher speeds. */
287 if (data->config & MAX6650_CFG_V12)
288 pwm = 255 - (255 * (int)data->dac)/180;
289 else
290 pwm = 255 - (255 * (int)data->dac)/76;
291
292 if (pwm < 0)
293 pwm = 0;
294
295 return sprintf(buf, "%d\n", pwm);
296}
297
298static ssize_t set_pwm(struct device *dev, struct device_attribute *devattr,
299 const char *buf, size_t count)
300{
301 struct i2c_client *client = to_i2c_client(dev);
302 struct max6650_data *data = i2c_get_clientdata(client);
303 int pwm = simple_strtoul(buf, NULL, 10);
304
305 pwm = SENSORS_LIMIT(pwm, 0, 255);
306
307 mutex_lock(&data->update_lock);
308
309 if (data->config & MAX6650_CFG_V12)
310 data->dac = 180 - (180 * pwm)/255;
311 else
312 data->dac = 76 - (76 * pwm)/255;
313
314 i2c_smbus_write_byte_data(client, MAX6650_REG_DAC, data->dac);
315
316 mutex_unlock(&data->update_lock);
317
318 return count;
319}
320
321/*
322 * Get/Set controller mode:
323 * Possible values:
324 * 0 = Fan always on
325 * 1 = Open loop, Voltage is set according to speed, not regulated.
326 * 2 = Closed loop, RPM for all fans regulated by fan1 tachometer
327 */
328
329static ssize_t get_enable(struct device *dev, struct device_attribute *devattr,
330 char *buf)
331{
332 struct max6650_data *data = max6650_update_device(dev);
333 int mode = (data->config & MAX6650_CFG_MODE_MASK) >> 4;
334 int sysfs_modes[4] = {0, 1, 2, 1};
335
336 return sprintf(buf, "%d\n", sysfs_modes[mode]);
337}
338
339static ssize_t set_enable(struct device *dev, struct device_attribute *devattr,
340 const char *buf, size_t count)
341{
342 struct i2c_client *client = to_i2c_client(dev);
343 struct max6650_data *data = i2c_get_clientdata(client);
344 int mode = simple_strtoul(buf, NULL, 10);
345 int max6650_modes[3] = {0, 3, 2};
346
347 if ((mode < 0)||(mode > 2)) {
348 dev_err(&client->dev,
349 "illegal value for pwm1_enable (%d)\n", mode);
350 return -EINVAL;
351 }
352
353 mutex_lock(&data->update_lock);
354
355 data->config = i2c_smbus_read_byte_data(client, MAX6650_REG_CONFIG);
356 data->config = (data->config & ~MAX6650_CFG_MODE_MASK)
357 | (max6650_modes[mode] << 4);
358
359 i2c_smbus_write_byte_data(client, MAX6650_REG_CONFIG, data->config);
360
361 mutex_unlock(&data->update_lock);
362
363 return count;
364}
365
366/*
367 * Read/write functions for fan1_div sysfs file. The MAX6650 has no such
368 * divider. We handle this by converting between divider and counttime:
369 *
370 * (counttime == k) <==> (divider == 2^k), k = 0, 1, 2, or 3
371 *
372 * Lower values of k allow to connect a faster fan without the risk of
373 * counter overflow. The price is lower resolution. You can also set counttime
374 * using the module parameter. Note that the module parameter "prescaler" also
375 * influences the behaviour. Unfortunately, there's no sysfs attribute
376 * defined for that. See the data sheet for details.
377 */
378
379static ssize_t get_div(struct device *dev, struct device_attribute *devattr,
380 char *buf)
381{
382 struct max6650_data *data = max6650_update_device(dev);
383
384 return sprintf(buf, "%d\n", DIV_FROM_REG(data->count));
385}
386
387static ssize_t set_div(struct device *dev, struct device_attribute *devattr,
388 const char *buf, size_t count)
389{
390 struct i2c_client *client = to_i2c_client(dev);
391 struct max6650_data *data = i2c_get_clientdata(client);
392 int div = simple_strtoul(buf, NULL, 10);
393
394 mutex_lock(&data->update_lock);
395 switch (div) {
396 case 1:
397 data->count = 0;
398 break;
399 case 2:
400 data->count = 1;
401 break;
402 case 4:
403 data->count = 2;
404 break;
405 case 8:
406 data->count = 3;
407 break;
408 default:
409 mutex_unlock(&data->update_lock);
410 dev_err(&client->dev,
411 "illegal value for fan divider (%d)\n", div);
412 return -EINVAL;
413 }
414
415 i2c_smbus_write_byte_data(client, MAX6650_REG_COUNT, data->count);
416 mutex_unlock(&data->update_lock);
417
418 return count;
419}
420
421/*
422 * Get alarm stati:
423 * Possible values:
424 * 0 = no alarm
425 * 1 = alarm
426 */
427
428static ssize_t get_alarm(struct device *dev, struct device_attribute *devattr,
429 char *buf)
430{
431 struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
432 struct max6650_data *data = max6650_update_device(dev);
433 struct i2c_client *client = to_i2c_client(dev);
434 int alarm = 0;
435
436 if (data->alarm & attr->index) {
437 mutex_lock(&data->update_lock);
438 alarm = 1;
439 data->alarm &= ~attr->index;
440 data->alarm |= i2c_smbus_read_byte_data(client,
441 MAX6650_REG_ALARM);
442 mutex_unlock(&data->update_lock);
443 }
444
445 return sprintf(buf, "%d\n", alarm);
446}
447
448static SENSOR_DEVICE_ATTR(fan1_input, S_IRUGO, get_fan, NULL, 0);
449static SENSOR_DEVICE_ATTR(fan2_input, S_IRUGO, get_fan, NULL, 1);
450static SENSOR_DEVICE_ATTR(fan3_input, S_IRUGO, get_fan, NULL, 2);
451static SENSOR_DEVICE_ATTR(fan4_input, S_IRUGO, get_fan, NULL, 3);
452static DEVICE_ATTR(fan1_target, S_IWUSR | S_IRUGO, get_target, set_target);
453static DEVICE_ATTR(fan1_div, S_IWUSR | S_IRUGO, get_div, set_div);
454static DEVICE_ATTR(pwm1_enable, S_IWUSR | S_IRUGO, get_enable, set_enable);
455static DEVICE_ATTR(pwm1, S_IWUSR | S_IRUGO, get_pwm, set_pwm);
456static SENSOR_DEVICE_ATTR(fan1_max_alarm, S_IRUGO, get_alarm, NULL,
457 MAX6650_ALRM_MAX);
458static SENSOR_DEVICE_ATTR(fan1_min_alarm, S_IRUGO, get_alarm, NULL,
459 MAX6650_ALRM_MIN);
460static SENSOR_DEVICE_ATTR(fan1_fault, S_IRUGO, get_alarm, NULL,
461 MAX6650_ALRM_TACH);
462static SENSOR_DEVICE_ATTR(gpio1_alarm, S_IRUGO, get_alarm, NULL,
463 MAX6650_ALRM_GPIO1);
464static SENSOR_DEVICE_ATTR(gpio2_alarm, S_IRUGO, get_alarm, NULL,
465 MAX6650_ALRM_GPIO2);
466
467static mode_t max6650_attrs_visible(struct kobject *kobj, struct attribute *a,
468 int n)
469{
470 struct device *dev = container_of(kobj, struct device, kobj);
471 struct i2c_client *client = to_i2c_client(dev);
472 u8 alarm_en = i2c_smbus_read_byte_data(client, MAX6650_REG_ALARM_EN);
473 struct device_attribute *devattr;
474
475 /*
476 * Hide the alarms that have not been enabled by the firmware
477 */
478
479 devattr = container_of(a, struct device_attribute, attr);
480 if (devattr == &sensor_dev_attr_fan1_max_alarm.dev_attr
481 || devattr == &sensor_dev_attr_fan1_min_alarm.dev_attr
482 || devattr == &sensor_dev_attr_fan1_fault.dev_attr
483 || devattr == &sensor_dev_attr_gpio1_alarm.dev_attr
484 || devattr == &sensor_dev_attr_gpio2_alarm.dev_attr) {
485 if (!(alarm_en & to_sensor_dev_attr(devattr)->index))
486 return 0;
487 }
488
489 return a->mode;
490}
491
492static struct attribute *max6650_attrs[] = {
493 &sensor_dev_attr_fan1_input.dev_attr.attr,
494 &dev_attr_fan1_target.attr,
495 &dev_attr_fan1_div.attr,
496 &dev_attr_pwm1_enable.attr,
497 &dev_attr_pwm1.attr,
498 &sensor_dev_attr_fan1_max_alarm.dev_attr.attr,
499 &sensor_dev_attr_fan1_min_alarm.dev_attr.attr,
500 &sensor_dev_attr_fan1_fault.dev_attr.attr,
501 &sensor_dev_attr_gpio1_alarm.dev_attr.attr,
502 &sensor_dev_attr_gpio2_alarm.dev_attr.attr,
503 NULL
504};
505
506static struct attribute_group max6650_attr_grp = {
507 .attrs = max6650_attrs,
508 .is_visible = max6650_attrs_visible,
509};
510
511static struct attribute *max6651_attrs[] = {
512 &sensor_dev_attr_fan2_input.dev_attr.attr,
513 &sensor_dev_attr_fan3_input.dev_attr.attr,
514 &sensor_dev_attr_fan4_input.dev_attr.attr,
515 NULL
516};
517
518static const struct attribute_group max6651_attr_grp = {
519 .attrs = max6651_attrs,
520};
521
522/*
523 * Real code
524 */
525
526static int max6650_probe(struct i2c_client *client,
527 const struct i2c_device_id *id)
528{
529 struct max6650_data *data;
530 int err;
531
532 if (!(data = kzalloc(sizeof(struct max6650_data), GFP_KERNEL))) {
533 dev_err(&client->dev, "out of memory.\n");
534 return -ENOMEM;
535 }
536
537 i2c_set_clientdata(client, data);
538 mutex_init(&data->update_lock);
539 data->nr_fans = id->driver_data;
540
541 /*
542 * Initialize the max6650 chip
543 */
544 err = max6650_init_client(client);
545 if (err)
546 goto err_free;
547
548 err = sysfs_create_group(&client->dev.kobj, &max6650_attr_grp);
549 if (err)
550 goto err_free;
551 /* 3 additional fan inputs for the MAX6651 */
552 if (data->nr_fans == 4) {
553 err = sysfs_create_group(&client->dev.kobj, &max6651_attr_grp);
554 if (err)
555 goto err_remove;
556 }
557
558 data->hwmon_dev = hwmon_device_register(&client->dev);
559 if (!IS_ERR(data->hwmon_dev))
560 return 0;
561
562 err = PTR_ERR(data->hwmon_dev);
563 dev_err(&client->dev, "error registering hwmon device.\n");
564 if (data->nr_fans == 4)
565 sysfs_remove_group(&client->dev.kobj, &max6651_attr_grp);
566err_remove:
567 sysfs_remove_group(&client->dev.kobj, &max6650_attr_grp);
568err_free:
569 kfree(data);
570 return err;
571}
572
573static int max6650_remove(struct i2c_client *client)
574{
575 struct max6650_data *data = i2c_get_clientdata(client);
576
577 hwmon_device_unregister(data->hwmon_dev);
578 if (data->nr_fans == 4)
579 sysfs_remove_group(&client->dev.kobj, &max6651_attr_grp);
580 sysfs_remove_group(&client->dev.kobj, &max6650_attr_grp);
581 kfree(data);
582 return 0;
583}
584
585static int max6650_init_client(struct i2c_client *client)
586{
587 struct max6650_data *data = i2c_get_clientdata(client);
588 int config;
589 int err = -EIO;
590
591 config = i2c_smbus_read_byte_data(client, MAX6650_REG_CONFIG);
592
593 if (config < 0) {
594 dev_err(&client->dev, "Error reading config, aborting.\n");
595 return err;
596 }
597
598 switch (fan_voltage) {
599 case 0:
600 break;
601 case 5:
602 config &= ~MAX6650_CFG_V12;
603 break;
604 case 12:
605 config |= MAX6650_CFG_V12;
606 break;
607 default:
608 dev_err(&client->dev,
609 "illegal value for fan_voltage (%d)\n",
610 fan_voltage);
611 }
612
613 dev_info(&client->dev, "Fan voltage is set to %dV.\n",
614 (config & MAX6650_CFG_V12) ? 12 : 5);
615
616 switch (prescaler) {
617 case 0:
618 break;
619 case 1:
620 config &= ~MAX6650_CFG_PRESCALER_MASK;
621 break;
622 case 2:
623 config = (config & ~MAX6650_CFG_PRESCALER_MASK)
624 | MAX6650_CFG_PRESCALER_2;
625 break;
626 case 4:
627 config = (config & ~MAX6650_CFG_PRESCALER_MASK)
628 | MAX6650_CFG_PRESCALER_4;
629 break;
630 case 8:
631 config = (config & ~MAX6650_CFG_PRESCALER_MASK)
632 | MAX6650_CFG_PRESCALER_8;
633 break;
634 case 16:
635 config = (config & ~MAX6650_CFG_PRESCALER_MASK)
636 | MAX6650_CFG_PRESCALER_16;
637 break;
638 default:
639 dev_err(&client->dev,
640 "illegal value for prescaler (%d)\n",
641 prescaler);
642 }
643
644 dev_info(&client->dev, "Prescaler is set to %d.\n",
645 1 << (config & MAX6650_CFG_PRESCALER_MASK));
646
647 /* If mode is set to "full off", we change it to "open loop" and
648 * set DAC to 255, which has the same effect. We do this because
649 * there's no "full off" mode defined in hwmon specifcations.
650 */
651
652 if ((config & MAX6650_CFG_MODE_MASK) == MAX6650_CFG_MODE_OFF) {
653 dev_dbg(&client->dev, "Change mode to open loop, full off.\n");
654 config = (config & ~MAX6650_CFG_MODE_MASK)
655 | MAX6650_CFG_MODE_OPEN_LOOP;
656 if (i2c_smbus_write_byte_data(client, MAX6650_REG_DAC, 255)) {
657 dev_err(&client->dev, "DAC write error, aborting.\n");
658 return err;
659 }
660 }
661
662 if (i2c_smbus_write_byte_data(client, MAX6650_REG_CONFIG, config)) {
663 dev_err(&client->dev, "Config write error, aborting.\n");
664 return err;
665 }
666
667 data->config = config;
668 data->count = i2c_smbus_read_byte_data(client, MAX6650_REG_COUNT);
669
670 return 0;
671}
672
673static const u8 tach_reg[] = {
674 MAX6650_REG_TACH0,
675 MAX6650_REG_TACH1,
676 MAX6650_REG_TACH2,
677 MAX6650_REG_TACH3,
678};
679
680static struct max6650_data *max6650_update_device(struct device *dev)
681{
682 int i;
683 struct i2c_client *client = to_i2c_client(dev);
684 struct max6650_data *data = i2c_get_clientdata(client);
685
686 mutex_lock(&data->update_lock);
687
688 if (time_after(jiffies, data->last_updated + HZ) || !data->valid) {
689 data->speed = i2c_smbus_read_byte_data(client,
690 MAX6650_REG_SPEED);
691 data->config = i2c_smbus_read_byte_data(client,
692 MAX6650_REG_CONFIG);
693 for (i = 0; i < data->nr_fans; i++) {
694 data->tach[i] = i2c_smbus_read_byte_data(client,
695 tach_reg[i]);
696 }
697 data->count = i2c_smbus_read_byte_data(client,
698 MAX6650_REG_COUNT);
699 data->dac = i2c_smbus_read_byte_data(client, MAX6650_REG_DAC);
700
701 /* Alarms are cleared on read in case the condition that
702 * caused the alarm is removed. Keep the value latched here
703 * for providing the register through different alarm files. */
704 data->alarm |= i2c_smbus_read_byte_data(client,
705 MAX6650_REG_ALARM);
706
707 data->last_updated = jiffies;
708 data->valid = 1;
709 }
710
711 mutex_unlock(&data->update_lock);
712
713 return data;
714}
715
716static int __init sensors_max6650_init(void)
717{
718 return i2c_add_driver(&max6650_driver);
719}
720
721static void __exit sensors_max6650_exit(void)
722{
723 i2c_del_driver(&max6650_driver);
724}
725
726MODULE_AUTHOR("Hans J. Koch");
727MODULE_DESCRIPTION("MAX6650 sensor driver");
728MODULE_LICENSE("GPL");
729
730module_init(sensors_max6650_init);
731module_exit(sensors_max6650_exit);
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");