2 * max6650.c - Part of lm_sensors, Linux kernel modules for hardware
5 * (C) 2007 by Hans J. Koch <hjk@hansjkoch.de>
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>
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
15 * The datasheet was last seen at:
17 * http://pdfserv.maxim-ic.com/en/ds/MAX6650-MAX6651.pdf
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.
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.
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.
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>
47 /* fan_voltage: 5=5V fan, 12=12V fan, 0=don't change */
48 static int fan_voltage;
49 /* prescaler: Possible values are 1, 2, 4, 8, 16 or 0 for don't change */
51 /* clock: The clock frequency of the chip the driver should assume */
52 static int clock = 254000;
54 module_param(fan_voltage, int, S_IRUGO);
55 module_param(prescaler, int, S_IRUGO);
56 module_param(clock, int, S_IRUGO);
59 * MAX 6650/6651 registers
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
76 * Config register bits
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
93 * Alarm status register bits
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
102 /* Minimum and maximum values of the FAN-RPM */
103 #define FAN_RPM_MIN 240
104 #define FAN_RPM_MAX 30000
106 #define DIV_FROM_REG(reg) (1 << (reg & 7))
109 * Client data (each client gets its own)
112 struct max6650_data {
113 struct device *hwmon_dev;
114 struct mutex update_lock;
116 char valid; /* zero until following fields are valid */
117 unsigned long last_updated; /* in jiffies */
119 /* register values */
128 static const u8 tach_reg[] = {
135 static struct max6650_data *max6650_update_device(struct device *dev)
138 struct i2c_client *client = to_i2c_client(dev);
139 struct max6650_data *data = i2c_get_clientdata(client);
141 mutex_lock(&data->update_lock);
143 if (time_after(jiffies, data->last_updated + HZ) || !data->valid) {
144 data->speed = i2c_smbus_read_byte_data(client,
146 data->config = i2c_smbus_read_byte_data(client,
148 for (i = 0; i < data->nr_fans; i++) {
149 data->tach[i] = i2c_smbus_read_byte_data(client,
152 data->count = i2c_smbus_read_byte_data(client,
154 data->dac = i2c_smbus_read_byte_data(client, MAX6650_REG_DAC);
157 * Alarms are cleared on read in case the condition that
158 * caused the alarm is removed. Keep the value latched here
159 * for providing the register through different alarm files.
161 data->alarm |= i2c_smbus_read_byte_data(client,
164 data->last_updated = jiffies;
168 mutex_unlock(&data->update_lock);
173 static ssize_t get_fan(struct device *dev, struct device_attribute *devattr,
176 struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
177 struct max6650_data *data = max6650_update_device(dev);
181 * Calculation details:
183 * Each tachometer counts over an interval given by the "count"
184 * register (0.25, 0.5, 1 or 2 seconds). This module assumes
185 * that the fans produce two pulses per revolution (this seems
186 * to be the most common).
189 rpm = ((data->tach[attr->index] * 120) / DIV_FROM_REG(data->count));
190 return sprintf(buf, "%d\n", rpm);
194 * Set the fan speed to the specified RPM (or read back the RPM setting).
195 * This works in closed loop mode only. Use pwm1 for open loop speed setting.
197 * The MAX6650/1 will automatically control fan speed when in closed loop
202 * 1) The MAX6650/1 internal 254kHz clock frequency is set correctly. Use
203 * the clock module parameter if you need to fine tune this.
205 * 2) The prescaler (low three bits of the config register) has already
206 * been set to an appropriate value. Use the prescaler module parameter
207 * if your BIOS doesn't initialize the chip properly.
209 * The relevant equations are given on pages 21 and 22 of the datasheet.
211 * From the datasheet, the relevant equation when in regulation is:
213 * [fCLK / (128 x (KTACH + 1))] = 2 x FanSpeed / KSCALE
217 * fCLK is the oscillator frequency (either the 254kHz internal
218 * oscillator or the externally applied clock)
220 * KTACH is the value in the speed register
222 * FanSpeed is the speed of the fan in rps
224 * KSCALE is the prescaler value (1, 2, 4, 8, or 16)
226 * When reading, we need to solve for FanSpeed. When writing, we need to
229 * Note: this tachometer is completely separate from the tachometers
230 * used to measure the fan speeds. Only one fan's speed (fan1) is
234 static ssize_t get_target(struct device *dev, struct device_attribute *devattr,
237 struct max6650_data *data = max6650_update_device(dev);
238 int kscale, ktach, rpm;
241 * Use the datasheet equation:
243 * FanSpeed = KSCALE x fCLK / [256 x (KTACH + 1)]
245 * then multiply by 60 to give rpm.
248 kscale = DIV_FROM_REG(data->config);
250 rpm = 60 * kscale * clock / (256 * (ktach + 1));
251 return sprintf(buf, "%d\n", rpm);
254 static ssize_t set_target(struct device *dev, struct device_attribute *devattr,
255 const char *buf, size_t count)
257 struct i2c_client *client = to_i2c_client(dev);
258 struct max6650_data *data = i2c_get_clientdata(client);
263 err = kstrtoul(buf, 10, &rpm);
267 rpm = clamp_val(rpm, FAN_RPM_MIN, FAN_RPM_MAX);
270 * Divide the required speed by 60 to get from rpm to rps, then
271 * use the datasheet equation:
273 * KTACH = [(fCLK x KSCALE) / (256 x FanSpeed)] - 1
276 mutex_lock(&data->update_lock);
278 kscale = DIV_FROM_REG(data->config);
279 ktach = ((clock * kscale) / (256 * rpm / 60)) - 1;
286 i2c_smbus_write_byte_data(client, MAX6650_REG_SPEED, data->speed);
288 mutex_unlock(&data->update_lock);
294 * Get/set the fan speed in open loop mode using pwm1 sysfs file.
295 * Speed is given as a relative value from 0 to 255, where 255 is maximum
296 * speed. Note that this is done by writing directly to the chip's DAC,
297 * it won't change the closed loop speed set by fan1_target.
298 * Also note that due to rounding errors it is possible that you don't read
299 * back exactly the value you have set.
302 static ssize_t get_pwm(struct device *dev, struct device_attribute *devattr,
306 struct max6650_data *data = max6650_update_device(dev);
309 * Useful range for dac is 0-180 for 12V fans and 0-76 for 5V fans.
310 * Lower DAC values mean higher speeds.
312 if (data->config & MAX6650_CFG_V12)
313 pwm = 255 - (255 * (int)data->dac)/180;
315 pwm = 255 - (255 * (int)data->dac)/76;
320 return sprintf(buf, "%d\n", pwm);
323 static ssize_t set_pwm(struct device *dev, struct device_attribute *devattr,
324 const char *buf, size_t count)
326 struct i2c_client *client = to_i2c_client(dev);
327 struct max6650_data *data = i2c_get_clientdata(client);
331 err = kstrtoul(buf, 10, &pwm);
335 pwm = clamp_val(pwm, 0, 255);
337 mutex_lock(&data->update_lock);
339 if (data->config & MAX6650_CFG_V12)
340 data->dac = 180 - (180 * pwm)/255;
342 data->dac = 76 - (76 * pwm)/255;
344 i2c_smbus_write_byte_data(client, MAX6650_REG_DAC, data->dac);
346 mutex_unlock(&data->update_lock);
352 * Get/Set controller mode:
355 * 1 = Open loop, Voltage is set according to speed, not regulated.
356 * 2 = Closed loop, RPM for all fans regulated by fan1 tachometer
359 static ssize_t get_enable(struct device *dev, struct device_attribute *devattr,
362 struct max6650_data *data = max6650_update_device(dev);
363 int mode = (data->config & MAX6650_CFG_MODE_MASK) >> 4;
364 int sysfs_modes[4] = {0, 1, 2, 1};
366 return sprintf(buf, "%d\n", sysfs_modes[mode]);
369 static ssize_t set_enable(struct device *dev, struct device_attribute *devattr,
370 const char *buf, size_t count)
372 struct i2c_client *client = to_i2c_client(dev);
373 struct max6650_data *data = i2c_get_clientdata(client);
374 int max6650_modes[3] = {0, 3, 2};
378 err = kstrtoul(buf, 10, &mode);
385 mutex_lock(&data->update_lock);
387 data->config = i2c_smbus_read_byte_data(client, MAX6650_REG_CONFIG);
388 data->config = (data->config & ~MAX6650_CFG_MODE_MASK)
389 | (max6650_modes[mode] << 4);
391 i2c_smbus_write_byte_data(client, MAX6650_REG_CONFIG, data->config);
393 mutex_unlock(&data->update_lock);
399 * Read/write functions for fan1_div sysfs file. The MAX6650 has no such
400 * divider. We handle this by converting between divider and counttime:
402 * (counttime == k) <==> (divider == 2^k), k = 0, 1, 2, or 3
404 * Lower values of k allow to connect a faster fan without the risk of
405 * counter overflow. The price is lower resolution. You can also set counttime
406 * using the module parameter. Note that the module parameter "prescaler" also
407 * influences the behaviour. Unfortunately, there's no sysfs attribute
408 * defined for that. See the data sheet for details.
411 static ssize_t get_div(struct device *dev, struct device_attribute *devattr,
414 struct max6650_data *data = max6650_update_device(dev);
416 return sprintf(buf, "%d\n", DIV_FROM_REG(data->count));
419 static ssize_t set_div(struct device *dev, struct device_attribute *devattr,
420 const char *buf, size_t count)
422 struct i2c_client *client = to_i2c_client(dev);
423 struct max6650_data *data = i2c_get_clientdata(client);
427 err = kstrtoul(buf, 10, &div);
431 mutex_lock(&data->update_lock);
446 mutex_unlock(&data->update_lock);
450 i2c_smbus_write_byte_data(client, MAX6650_REG_COUNT, data->count);
451 mutex_unlock(&data->update_lock);
463 static ssize_t get_alarm(struct device *dev, struct device_attribute *devattr,
466 struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
467 struct max6650_data *data = max6650_update_device(dev);
468 struct i2c_client *client = to_i2c_client(dev);
471 if (data->alarm & attr->index) {
472 mutex_lock(&data->update_lock);
474 data->alarm &= ~attr->index;
475 data->alarm |= i2c_smbus_read_byte_data(client,
477 mutex_unlock(&data->update_lock);
480 return sprintf(buf, "%d\n", alarm);
483 static SENSOR_DEVICE_ATTR(fan1_input, S_IRUGO, get_fan, NULL, 0);
484 static SENSOR_DEVICE_ATTR(fan2_input, S_IRUGO, get_fan, NULL, 1);
485 static SENSOR_DEVICE_ATTR(fan3_input, S_IRUGO, get_fan, NULL, 2);
486 static SENSOR_DEVICE_ATTR(fan4_input, S_IRUGO, get_fan, NULL, 3);
487 static DEVICE_ATTR(fan1_target, S_IWUSR | S_IRUGO, get_target, set_target);
488 static DEVICE_ATTR(fan1_div, S_IWUSR | S_IRUGO, get_div, set_div);
489 static DEVICE_ATTR(pwm1_enable, S_IWUSR | S_IRUGO, get_enable, set_enable);
490 static DEVICE_ATTR(pwm1, S_IWUSR | S_IRUGO, get_pwm, set_pwm);
491 static SENSOR_DEVICE_ATTR(fan1_max_alarm, S_IRUGO, get_alarm, NULL,
493 static SENSOR_DEVICE_ATTR(fan1_min_alarm, S_IRUGO, get_alarm, NULL,
495 static SENSOR_DEVICE_ATTR(fan1_fault, S_IRUGO, get_alarm, NULL,
497 static SENSOR_DEVICE_ATTR(gpio1_alarm, S_IRUGO, get_alarm, NULL,
499 static SENSOR_DEVICE_ATTR(gpio2_alarm, S_IRUGO, get_alarm, NULL,
502 static umode_t max6650_attrs_visible(struct kobject *kobj, struct attribute *a,
505 struct device *dev = container_of(kobj, struct device, kobj);
506 struct i2c_client *client = to_i2c_client(dev);
507 u8 alarm_en = i2c_smbus_read_byte_data(client, MAX6650_REG_ALARM_EN);
508 struct device_attribute *devattr;
511 * Hide the alarms that have not been enabled by the firmware
514 devattr = container_of(a, struct device_attribute, attr);
515 if (devattr == &sensor_dev_attr_fan1_max_alarm.dev_attr
516 || devattr == &sensor_dev_attr_fan1_min_alarm.dev_attr
517 || devattr == &sensor_dev_attr_fan1_fault.dev_attr
518 || devattr == &sensor_dev_attr_gpio1_alarm.dev_attr
519 || devattr == &sensor_dev_attr_gpio2_alarm.dev_attr) {
520 if (!(alarm_en & to_sensor_dev_attr(devattr)->index))
527 static struct attribute *max6650_attrs[] = {
528 &sensor_dev_attr_fan1_input.dev_attr.attr,
529 &dev_attr_fan1_target.attr,
530 &dev_attr_fan1_div.attr,
531 &dev_attr_pwm1_enable.attr,
533 &sensor_dev_attr_fan1_max_alarm.dev_attr.attr,
534 &sensor_dev_attr_fan1_min_alarm.dev_attr.attr,
535 &sensor_dev_attr_fan1_fault.dev_attr.attr,
536 &sensor_dev_attr_gpio1_alarm.dev_attr.attr,
537 &sensor_dev_attr_gpio2_alarm.dev_attr.attr,
541 static struct attribute_group max6650_attr_grp = {
542 .attrs = max6650_attrs,
543 .is_visible = max6650_attrs_visible,
546 static struct attribute *max6651_attrs[] = {
547 &sensor_dev_attr_fan2_input.dev_attr.attr,
548 &sensor_dev_attr_fan3_input.dev_attr.attr,
549 &sensor_dev_attr_fan4_input.dev_attr.attr,
553 static const struct attribute_group max6651_attr_grp = {
554 .attrs = max6651_attrs,
561 static int max6650_init_client(struct i2c_client *client)
563 struct max6650_data *data = i2c_get_clientdata(client);
567 config = i2c_smbus_read_byte_data(client, MAX6650_REG_CONFIG);
570 dev_err(&client->dev, "Error reading config, aborting.\n");
574 switch (fan_voltage) {
578 config &= ~MAX6650_CFG_V12;
581 config |= MAX6650_CFG_V12;
584 dev_err(&client->dev, "illegal value for fan_voltage (%d)\n",
588 dev_info(&client->dev, "Fan voltage is set to %dV.\n",
589 (config & MAX6650_CFG_V12) ? 12 : 5);
595 config &= ~MAX6650_CFG_PRESCALER_MASK;
598 config = (config & ~MAX6650_CFG_PRESCALER_MASK)
599 | MAX6650_CFG_PRESCALER_2;
602 config = (config & ~MAX6650_CFG_PRESCALER_MASK)
603 | MAX6650_CFG_PRESCALER_4;
606 config = (config & ~MAX6650_CFG_PRESCALER_MASK)
607 | MAX6650_CFG_PRESCALER_8;
610 config = (config & ~MAX6650_CFG_PRESCALER_MASK)
611 | MAX6650_CFG_PRESCALER_16;
614 dev_err(&client->dev, "illegal value for prescaler (%d)\n",
618 dev_info(&client->dev, "Prescaler is set to %d.\n",
619 1 << (config & MAX6650_CFG_PRESCALER_MASK));
622 * If mode is set to "full off", we change it to "open loop" and
623 * set DAC to 255, which has the same effect. We do this because
624 * there's no "full off" mode defined in hwmon specifications.
627 if ((config & MAX6650_CFG_MODE_MASK) == MAX6650_CFG_MODE_OFF) {
628 dev_dbg(&client->dev, "Change mode to open loop, full off.\n");
629 config = (config & ~MAX6650_CFG_MODE_MASK)
630 | MAX6650_CFG_MODE_OPEN_LOOP;
631 if (i2c_smbus_write_byte_data(client, MAX6650_REG_DAC, 255)) {
632 dev_err(&client->dev, "DAC write error, aborting.\n");
637 if (i2c_smbus_write_byte_data(client, MAX6650_REG_CONFIG, config)) {
638 dev_err(&client->dev, "Config write error, aborting.\n");
642 data->config = config;
643 data->count = i2c_smbus_read_byte_data(client, MAX6650_REG_COUNT);
648 static int max6650_probe(struct i2c_client *client,
649 const struct i2c_device_id *id)
651 struct max6650_data *data;
654 data = devm_kzalloc(&client->dev, sizeof(struct max6650_data),
657 dev_err(&client->dev, "out of memory.\n");
661 i2c_set_clientdata(client, data);
662 mutex_init(&data->update_lock);
663 data->nr_fans = id->driver_data;
666 * Initialize the max6650 chip
668 err = max6650_init_client(client);
672 err = sysfs_create_group(&client->dev.kobj, &max6650_attr_grp);
675 /* 3 additional fan inputs for the MAX6651 */
676 if (data->nr_fans == 4) {
677 err = sysfs_create_group(&client->dev.kobj, &max6651_attr_grp);
682 data->hwmon_dev = hwmon_device_register(&client->dev);
683 if (!IS_ERR(data->hwmon_dev))
686 err = PTR_ERR(data->hwmon_dev);
687 dev_err(&client->dev, "error registering hwmon device.\n");
688 if (data->nr_fans == 4)
689 sysfs_remove_group(&client->dev.kobj, &max6651_attr_grp);
691 sysfs_remove_group(&client->dev.kobj, &max6650_attr_grp);
695 static int max6650_remove(struct i2c_client *client)
697 struct max6650_data *data = i2c_get_clientdata(client);
699 hwmon_device_unregister(data->hwmon_dev);
700 if (data->nr_fans == 4)
701 sysfs_remove_group(&client->dev.kobj, &max6651_attr_grp);
702 sysfs_remove_group(&client->dev.kobj, &max6650_attr_grp);
706 static const struct i2c_device_id max6650_id[] = {
711 MODULE_DEVICE_TABLE(i2c, max6650_id);
713 static struct i2c_driver max6650_driver = {
717 .probe = max6650_probe,
718 .remove = max6650_remove,
719 .id_table = max6650_id,
722 module_i2c_driver(max6650_driver);
724 MODULE_AUTHOR("Hans J. Koch");
725 MODULE_DESCRIPTION("MAX6650 sensor driver");
726 MODULE_LICENSE("GPL");