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 i2c_client *client;
114 const struct attribute_group *groups[3];
115 struct mutex update_lock;
117 char valid; /* zero until following fields are valid */
118 unsigned long last_updated; /* in jiffies */
120 /* register values */
129 static const u8 tach_reg[] = {
136 static struct max6650_data *max6650_update_device(struct device *dev)
138 struct max6650_data *data = dev_get_drvdata(dev);
139 struct i2c_client *client = data->client;
142 mutex_lock(&data->update_lock);
144 if (time_after(jiffies, data->last_updated + HZ) || !data->valid) {
145 data->speed = i2c_smbus_read_byte_data(client,
147 data->config = i2c_smbus_read_byte_data(client,
149 for (i = 0; i < data->nr_fans; i++) {
150 data->tach[i] = i2c_smbus_read_byte_data(client,
153 data->count = i2c_smbus_read_byte_data(client,
155 data->dac = i2c_smbus_read_byte_data(client, MAX6650_REG_DAC);
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.
162 data->alarm |= i2c_smbus_read_byte_data(client,
165 data->last_updated = jiffies;
169 mutex_unlock(&data->update_lock);
174 static ssize_t get_fan(struct device *dev, struct device_attribute *devattr,
177 struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
178 struct max6650_data *data = max6650_update_device(dev);
182 * Calculation details:
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).
190 rpm = ((data->tach[attr->index] * 120) / DIV_FROM_REG(data->count));
191 return sprintf(buf, "%d\n", rpm);
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.
198 * The MAX6650/1 will automatically control fan speed when in closed loop
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.
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.
210 * The relevant equations are given on pages 21 and 22 of the datasheet.
212 * From the datasheet, the relevant equation when in regulation is:
214 * [fCLK / (128 x (KTACH + 1))] = 2 x FanSpeed / KSCALE
218 * fCLK is the oscillator frequency (either the 254kHz internal
219 * oscillator or the externally applied clock)
221 * KTACH is the value in the speed register
223 * FanSpeed is the speed of the fan in rps
225 * KSCALE is the prescaler value (1, 2, 4, 8, or 16)
227 * When reading, we need to solve for FanSpeed. When writing, we need to
230 * Note: this tachometer is completely separate from the tachometers
231 * used to measure the fan speeds. Only one fan's speed (fan1) is
235 static ssize_t get_target(struct device *dev, struct device_attribute *devattr,
238 struct max6650_data *data = max6650_update_device(dev);
239 int kscale, ktach, rpm;
242 * Use the datasheet equation:
244 * FanSpeed = KSCALE x fCLK / [256 x (KTACH + 1)]
246 * then multiply by 60 to give rpm.
249 kscale = DIV_FROM_REG(data->config);
251 rpm = 60 * kscale * clock / (256 * (ktach + 1));
252 return sprintf(buf, "%d\n", rpm);
255 static ssize_t set_target(struct device *dev, struct device_attribute *devattr,
256 const char *buf, size_t count)
258 struct max6650_data *data = dev_get_drvdata(dev);
259 struct i2c_client *client = data->client;
264 err = kstrtoul(buf, 10, &rpm);
268 rpm = clamp_val(rpm, FAN_RPM_MIN, FAN_RPM_MAX);
271 * Divide the required speed by 60 to get from rpm to rps, then
272 * use the datasheet equation:
274 * KTACH = [(fCLK x KSCALE) / (256 x FanSpeed)] - 1
277 mutex_lock(&data->update_lock);
279 kscale = DIV_FROM_REG(data->config);
280 ktach = ((clock * kscale) / (256 * rpm / 60)) - 1;
287 i2c_smbus_write_byte_data(client, MAX6650_REG_SPEED, data->speed);
289 mutex_unlock(&data->update_lock);
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.
303 static ssize_t get_pwm(struct device *dev, struct device_attribute *devattr,
307 struct max6650_data *data = max6650_update_device(dev);
310 * Useful range for dac is 0-180 for 12V fans and 0-76 for 5V fans.
311 * Lower DAC values mean higher speeds.
313 if (data->config & MAX6650_CFG_V12)
314 pwm = 255 - (255 * (int)data->dac)/180;
316 pwm = 255 - (255 * (int)data->dac)/76;
321 return sprintf(buf, "%d\n", pwm);
324 static ssize_t set_pwm(struct device *dev, struct device_attribute *devattr,
325 const char *buf, size_t count)
327 struct max6650_data *data = dev_get_drvdata(dev);
328 struct i2c_client *client = data->client;
332 err = kstrtoul(buf, 10, &pwm);
336 pwm = clamp_val(pwm, 0, 255);
338 mutex_lock(&data->update_lock);
340 if (data->config & MAX6650_CFG_V12)
341 data->dac = 180 - (180 * pwm)/255;
343 data->dac = 76 - (76 * pwm)/255;
345 i2c_smbus_write_byte_data(client, MAX6650_REG_DAC, data->dac);
347 mutex_unlock(&data->update_lock);
353 * Get/Set controller mode:
356 * 1 = Open loop, Voltage is set according to speed, not regulated.
357 * 2 = Closed loop, RPM for all fans regulated by fan1 tachometer
360 static ssize_t get_enable(struct device *dev, struct device_attribute *devattr,
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};
367 return sprintf(buf, "%d\n", sysfs_modes[mode]);
370 static ssize_t set_enable(struct device *dev, struct device_attribute *devattr,
371 const char *buf, size_t count)
373 struct max6650_data *data = dev_get_drvdata(dev);
374 struct i2c_client *client = data->client;
375 int max6650_modes[3] = {0, 3, 2};
379 err = kstrtoul(buf, 10, &mode);
386 mutex_lock(&data->update_lock);
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);
392 i2c_smbus_write_byte_data(client, MAX6650_REG_CONFIG, data->config);
394 mutex_unlock(&data->update_lock);
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:
403 * (counttime == k) <==> (divider == 2^k), k = 0, 1, 2, or 3
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.
412 static ssize_t get_div(struct device *dev, struct device_attribute *devattr,
415 struct max6650_data *data = max6650_update_device(dev);
417 return sprintf(buf, "%d\n", DIV_FROM_REG(data->count));
420 static ssize_t set_div(struct device *dev, struct device_attribute *devattr,
421 const char *buf, size_t count)
423 struct max6650_data *data = dev_get_drvdata(dev);
424 struct i2c_client *client = data->client;
428 err = kstrtoul(buf, 10, &div);
432 mutex_lock(&data->update_lock);
447 mutex_unlock(&data->update_lock);
451 i2c_smbus_write_byte_data(client, MAX6650_REG_COUNT, data->count);
452 mutex_unlock(&data->update_lock);
464 static ssize_t get_alarm(struct device *dev, struct device_attribute *devattr,
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;
472 if (data->alarm & attr->index) {
473 mutex_lock(&data->update_lock);
475 data->alarm &= ~attr->index;
476 data->alarm |= i2c_smbus_read_byte_data(client,
478 mutex_unlock(&data->update_lock);
481 return sprintf(buf, "%d\n", alarm);
484 static SENSOR_DEVICE_ATTR(fan1_input, S_IRUGO, get_fan, NULL, 0);
485 static SENSOR_DEVICE_ATTR(fan2_input, S_IRUGO, get_fan, NULL, 1);
486 static SENSOR_DEVICE_ATTR(fan3_input, S_IRUGO, get_fan, NULL, 2);
487 static SENSOR_DEVICE_ATTR(fan4_input, S_IRUGO, get_fan, NULL, 3);
488 static DEVICE_ATTR(fan1_target, S_IWUSR | S_IRUGO, get_target, set_target);
489 static DEVICE_ATTR(fan1_div, S_IWUSR | S_IRUGO, get_div, set_div);
490 static DEVICE_ATTR(pwm1_enable, S_IWUSR | S_IRUGO, get_enable, set_enable);
491 static DEVICE_ATTR(pwm1, S_IWUSR | S_IRUGO, get_pwm, set_pwm);
492 static SENSOR_DEVICE_ATTR(fan1_max_alarm, S_IRUGO, get_alarm, NULL,
494 static SENSOR_DEVICE_ATTR(fan1_min_alarm, S_IRUGO, get_alarm, NULL,
496 static SENSOR_DEVICE_ATTR(fan1_fault, S_IRUGO, get_alarm, NULL,
498 static SENSOR_DEVICE_ATTR(gpio1_alarm, S_IRUGO, get_alarm, NULL,
500 static SENSOR_DEVICE_ATTR(gpio2_alarm, S_IRUGO, get_alarm, NULL,
503 static umode_t max6650_attrs_visible(struct kobject *kobj, struct attribute *a,
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;
513 * Hide the alarms that have not been enabled by the firmware
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))
529 static 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,
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,
543 static const struct attribute_group max6650_group = {
544 .attrs = max6650_attrs,
545 .is_visible = max6650_attrs_visible,
548 static 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,
555 static const struct attribute_group max6651_group = {
556 .attrs = max6651_attrs,
563 static int max6650_init_client(struct max6650_data *data,
564 struct i2c_client *client)
566 struct device *dev = &client->dev;
570 config = i2c_smbus_read_byte_data(client, MAX6650_REG_CONFIG);
573 dev_err(dev, "Error reading config, aborting.\n");
577 switch (fan_voltage) {
581 config &= ~MAX6650_CFG_V12;
584 config |= MAX6650_CFG_V12;
587 dev_err(dev, "illegal value for fan_voltage (%d)\n",
591 dev_info(dev, "Fan voltage is set to %dV.\n",
592 (config & MAX6650_CFG_V12) ? 12 : 5);
598 config &= ~MAX6650_CFG_PRESCALER_MASK;
601 config = (config & ~MAX6650_CFG_PRESCALER_MASK)
602 | MAX6650_CFG_PRESCALER_2;
605 config = (config & ~MAX6650_CFG_PRESCALER_MASK)
606 | MAX6650_CFG_PRESCALER_4;
609 config = (config & ~MAX6650_CFG_PRESCALER_MASK)
610 | MAX6650_CFG_PRESCALER_8;
613 config = (config & ~MAX6650_CFG_PRESCALER_MASK)
614 | MAX6650_CFG_PRESCALER_16;
617 dev_err(dev, "illegal value for prescaler (%d)\n", prescaler);
620 dev_info(dev, "Prescaler is set to %d.\n",
621 1 << (config & MAX6650_CFG_PRESCALER_MASK));
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.
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");
639 if (i2c_smbus_write_byte_data(client, MAX6650_REG_CONFIG, config)) {
640 dev_err(dev, "Config write error, aborting.\n");
644 data->config = config;
645 data->count = i2c_smbus_read_byte_data(client, MAX6650_REG_COUNT);
650 static int max6650_probe(struct i2c_client *client,
651 const struct i2c_device_id *id)
653 struct device *dev = &client->dev;
654 struct max6650_data *data;
655 struct device *hwmon_dev;
658 data = devm_kzalloc(dev, sizeof(struct max6650_data), GFP_KERNEL);
662 data->client = client;
663 mutex_init(&data->update_lock);
664 data->nr_fans = id->driver_data;
667 * Initialize the max6650 chip
669 err = max6650_init_client(data, client);
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;
678 hwmon_dev = devm_hwmon_device_register_with_groups(dev,
681 return PTR_ERR_OR_ZERO(hwmon_dev);
684 static const struct i2c_device_id max6650_id[] = {
689 MODULE_DEVICE_TABLE(i2c, max6650_id);
691 static struct i2c_driver max6650_driver = {
695 .probe = max6650_probe,
696 .id_table = max6650_id,
699 module_i2c_driver(max6650_driver);
701 MODULE_AUTHOR("Hans J. Koch");
702 MODULE_DESCRIPTION("MAX6650 sensor driver");
703 MODULE_LICENSE("GPL");