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>
42 #include <linux/of_device.h>
43 #include <linux/thermal.h>
49 /* fan_voltage: 5=5V fan, 12=12V fan, 0=don't change */
50 static int fan_voltage;
51 /* prescaler: Possible values are 1, 2, 4, 8, 16 or 0 for don't change */
53 /* clock: The clock frequency of the chip (max6651 can be clocked externally) */
54 static int clock = 254000;
56 module_param(fan_voltage, int, 0444);
57 module_param(prescaler, int, 0444);
58 module_param(clock, int, 0444);
61 * MAX 6650/6651 registers
64 #define MAX6650_REG_SPEED 0x00
65 #define MAX6650_REG_CONFIG 0x02
66 #define MAX6650_REG_GPIO_DEF 0x04
67 #define MAX6650_REG_DAC 0x06
68 #define MAX6650_REG_ALARM_EN 0x08
69 #define MAX6650_REG_ALARM 0x0A
70 #define MAX6650_REG_TACH0 0x0C
71 #define MAX6650_REG_TACH1 0x0E
72 #define MAX6650_REG_TACH2 0x10
73 #define MAX6650_REG_TACH3 0x12
74 #define MAX6650_REG_GPIO_STAT 0x14
75 #define MAX6650_REG_COUNT 0x16
78 * Config register bits
81 #define MAX6650_CFG_V12 0x08
82 #define MAX6650_CFG_PRESCALER_MASK 0x07
83 #define MAX6650_CFG_PRESCALER_2 0x01
84 #define MAX6650_CFG_PRESCALER_4 0x02
85 #define MAX6650_CFG_PRESCALER_8 0x03
86 #define MAX6650_CFG_PRESCALER_16 0x04
87 #define MAX6650_CFG_MODE_MASK 0x30
88 #define MAX6650_CFG_MODE_ON 0x00
89 #define MAX6650_CFG_MODE_OFF 0x10
90 #define MAX6650_CFG_MODE_CLOSED_LOOP 0x20
91 #define MAX6650_CFG_MODE_OPEN_LOOP 0x30
92 #define MAX6650_COUNT_MASK 0x03
95 * Alarm status register bits
98 #define MAX6650_ALRM_MAX 0x01
99 #define MAX6650_ALRM_MIN 0x02
100 #define MAX6650_ALRM_TACH 0x04
101 #define MAX6650_ALRM_GPIO1 0x08
102 #define MAX6650_ALRM_GPIO2 0x10
104 /* Minimum and maximum values of the FAN-RPM */
105 #define FAN_RPM_MIN 240
106 #define FAN_RPM_MAX 30000
108 #define DIV_FROM_REG(reg) (1 << (reg & 7))
111 * Client data (each client gets its own)
114 struct max6650_data {
115 struct i2c_client *client;
116 const struct attribute_group *groups[3];
117 struct thermal_cooling_device *cooling_dev;
118 struct mutex update_lock;
120 char valid; /* zero until following fields are valid */
121 unsigned long last_updated; /* in jiffies */
123 /* register values */
130 unsigned long cooling_dev_state;
133 static const u8 tach_reg[] = {
140 static const struct of_device_id __maybe_unused max6650_dt_match[] = {
142 .compatible = "maxim,max6650",
146 .compatible = "maxim,max6651",
151 MODULE_DEVICE_TABLE(of, max6650_dt_match);
153 static struct max6650_data *max6650_update_device(struct device *dev)
155 struct max6650_data *data = dev_get_drvdata(dev);
156 struct i2c_client *client = data->client;
159 mutex_lock(&data->update_lock);
161 if (time_after(jiffies, data->last_updated + HZ) || !data->valid) {
162 data->speed = i2c_smbus_read_byte_data(client,
164 data->config = i2c_smbus_read_byte_data(client,
166 for (i = 0; i < data->nr_fans; i++) {
167 data->tach[i] = i2c_smbus_read_byte_data(client,
170 data->count = i2c_smbus_read_byte_data(client,
172 data->dac = i2c_smbus_read_byte_data(client, MAX6650_REG_DAC);
175 * Alarms are cleared on read in case the condition that
176 * caused the alarm is removed. Keep the value latched here
177 * for providing the register through different alarm files.
179 data->alarm |= i2c_smbus_read_byte_data(client,
182 data->last_updated = jiffies;
186 mutex_unlock(&data->update_lock);
192 * Change the operating mode of the chip (if needed).
193 * mode is one of the MAX6650_CFG_MODE_* values.
195 static int max6650_set_operating_mode(struct max6650_data *data, u8 mode)
198 u8 config = data->config;
200 if (mode == (config & MAX6650_CFG_MODE_MASK))
203 config = (config & ~MAX6650_CFG_MODE_MASK) | mode;
205 result = i2c_smbus_write_byte_data(data->client, MAX6650_REG_CONFIG,
210 data->config = config;
215 static ssize_t fan_show(struct device *dev, struct device_attribute *devattr,
218 struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
219 struct max6650_data *data = max6650_update_device(dev);
223 * Calculation details:
225 * Each tachometer counts over an interval given by the "count"
226 * register (0.25, 0.5, 1 or 2 seconds). This module assumes
227 * that the fans produce two pulses per revolution (this seems
228 * to be the most common).
231 rpm = ((data->tach[attr->index] * 120) / DIV_FROM_REG(data->count));
232 return sprintf(buf, "%d\n", rpm);
236 * Set the fan speed to the specified RPM (or read back the RPM setting).
237 * This works in closed loop mode only. Use pwm1 for open loop speed setting.
239 * The MAX6650/1 will automatically control fan speed when in closed loop
244 * 1) The MAX6650/1 internal 254kHz clock frequency is set correctly. Use
245 * the clock module parameter if you need to fine tune this.
247 * 2) The prescaler (low three bits of the config register) has already
248 * been set to an appropriate value. Use the prescaler module parameter
249 * if your BIOS doesn't initialize the chip properly.
251 * The relevant equations are given on pages 21 and 22 of the datasheet.
253 * From the datasheet, the relevant equation when in regulation is:
255 * [fCLK / (128 x (KTACH + 1))] = 2 x FanSpeed / KSCALE
259 * fCLK is the oscillator frequency (either the 254kHz internal
260 * oscillator or the externally applied clock)
262 * KTACH is the value in the speed register
264 * FanSpeed is the speed of the fan in rps
266 * KSCALE is the prescaler value (1, 2, 4, 8, or 16)
268 * When reading, we need to solve for FanSpeed. When writing, we need to
271 * Note: this tachometer is completely separate from the tachometers
272 * used to measure the fan speeds. Only one fan's speed (fan1) is
276 static ssize_t fan1_target_show(struct device *dev,
277 struct device_attribute *devattr, char *buf)
279 struct max6650_data *data = max6650_update_device(dev);
280 int kscale, ktach, rpm;
283 * Use the datasheet equation:
285 * FanSpeed = KSCALE x fCLK / [256 x (KTACH + 1)]
287 * then multiply by 60 to give rpm.
290 kscale = DIV_FROM_REG(data->config);
292 rpm = 60 * kscale * clock / (256 * (ktach + 1));
293 return sprintf(buf, "%d\n", rpm);
296 static int max6650_set_target(struct max6650_data *data, unsigned long rpm)
301 return max6650_set_operating_mode(data, MAX6650_CFG_MODE_OFF);
303 rpm = clamp_val(rpm, FAN_RPM_MIN, FAN_RPM_MAX);
306 * Divide the required speed by 60 to get from rpm to rps, then
307 * use the datasheet equation:
309 * KTACH = [(fCLK x KSCALE) / (256 x FanSpeed)] - 1
312 kscale = DIV_FROM_REG(data->config);
313 ktach = ((clock * kscale) / (256 * rpm / 60)) - 1;
320 return i2c_smbus_write_byte_data(data->client, MAX6650_REG_SPEED,
324 static ssize_t fan1_target_store(struct device *dev,
325 struct device_attribute *devattr,
326 const char *buf, size_t count)
328 struct max6650_data *data = dev_get_drvdata(dev);
332 err = kstrtoul(buf, 10, &rpm);
336 mutex_lock(&data->update_lock);
338 err = max6650_set_target(data, rpm);
340 mutex_unlock(&data->update_lock);
349 * Get/set the fan speed in open loop mode using pwm1 sysfs file.
350 * Speed is given as a relative value from 0 to 255, where 255 is maximum
351 * speed. Note that this is done by writing directly to the chip's DAC,
352 * it won't change the closed loop speed set by fan1_target.
353 * Also note that due to rounding errors it is possible that you don't read
354 * back exactly the value you have set.
357 static ssize_t pwm1_show(struct device *dev, struct device_attribute *devattr,
361 struct max6650_data *data = max6650_update_device(dev);
364 * Useful range for dac is 0-180 for 12V fans and 0-76 for 5V fans.
365 * Lower DAC values mean higher speeds.
367 if (data->config & MAX6650_CFG_V12)
368 pwm = 255 - (255 * (int)data->dac)/180;
370 pwm = 255 - (255 * (int)data->dac)/76;
375 return sprintf(buf, "%d\n", pwm);
378 static ssize_t pwm1_store(struct device *dev,
379 struct device_attribute *devattr, const char *buf,
382 struct max6650_data *data = dev_get_drvdata(dev);
383 struct i2c_client *client = data->client;
387 err = kstrtoul(buf, 10, &pwm);
391 pwm = clamp_val(pwm, 0, 255);
393 mutex_lock(&data->update_lock);
395 if (data->config & MAX6650_CFG_V12)
396 data->dac = 180 - (180 * pwm)/255;
398 data->dac = 76 - (76 * pwm)/255;
399 err = i2c_smbus_write_byte_data(client, MAX6650_REG_DAC, data->dac);
401 mutex_unlock(&data->update_lock);
403 return err < 0 ? err : count;
407 * Get/Set controller mode:
410 * 1 = Open loop, Voltage is set according to speed, not regulated.
411 * 2 = Closed loop, RPM for all fans regulated by fan1 tachometer
414 static ssize_t pwm1_enable_show(struct device *dev,
415 struct device_attribute *devattr, char *buf)
417 struct max6650_data *data = max6650_update_device(dev);
418 int mode = (data->config & MAX6650_CFG_MODE_MASK) >> 4;
419 int sysfs_modes[4] = {0, 3, 2, 1};
421 return sprintf(buf, "%d\n", sysfs_modes[mode]);
424 static ssize_t pwm1_enable_store(struct device *dev,
425 struct device_attribute *devattr,
426 const char *buf, size_t count)
428 struct max6650_data *data = dev_get_drvdata(dev);
431 const u8 max6650_modes[] = {
433 MAX6650_CFG_MODE_OPEN_LOOP,
434 MAX6650_CFG_MODE_CLOSED_LOOP,
435 MAX6650_CFG_MODE_OFF,
438 err = kstrtoul(buf, 10, &mode);
442 if (mode >= ARRAY_SIZE(max6650_modes))
445 mutex_lock(&data->update_lock);
447 max6650_set_operating_mode(data, max6650_modes[mode]);
449 mutex_unlock(&data->update_lock);
455 * Read/write functions for fan1_div sysfs file. The MAX6650 has no such
456 * divider. We handle this by converting between divider and counttime:
458 * (counttime == k) <==> (divider == 2^k), k = 0, 1, 2, or 3
460 * Lower values of k allow to connect a faster fan without the risk of
461 * counter overflow. The price is lower resolution. You can also set counttime
462 * using the module parameter. Note that the module parameter "prescaler" also
463 * influences the behaviour. Unfortunately, there's no sysfs attribute
464 * defined for that. See the data sheet for details.
467 static ssize_t fan1_div_show(struct device *dev,
468 struct device_attribute *devattr, char *buf)
470 struct max6650_data *data = max6650_update_device(dev);
472 return sprintf(buf, "%d\n", DIV_FROM_REG(data->count));
475 static ssize_t fan1_div_store(struct device *dev,
476 struct device_attribute *devattr,
477 const char *buf, size_t count)
479 struct max6650_data *data = dev_get_drvdata(dev);
480 struct i2c_client *client = data->client;
484 err = kstrtoul(buf, 10, &div);
488 mutex_lock(&data->update_lock);
503 mutex_unlock(&data->update_lock);
507 i2c_smbus_write_byte_data(client, MAX6650_REG_COUNT, data->count);
508 mutex_unlock(&data->update_lock);
520 static ssize_t alarm_show(struct device *dev,
521 struct device_attribute *devattr, char *buf)
523 struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
524 struct max6650_data *data = max6650_update_device(dev);
525 struct i2c_client *client = data->client;
528 if (data->alarm & attr->index) {
529 mutex_lock(&data->update_lock);
531 data->alarm &= ~attr->index;
532 data->alarm |= i2c_smbus_read_byte_data(client,
534 mutex_unlock(&data->update_lock);
537 return sprintf(buf, "%d\n", alarm);
540 static SENSOR_DEVICE_ATTR_RO(fan1_input, fan, 0);
541 static SENSOR_DEVICE_ATTR_RO(fan2_input, fan, 1);
542 static SENSOR_DEVICE_ATTR_RO(fan3_input, fan, 2);
543 static SENSOR_DEVICE_ATTR_RO(fan4_input, fan, 3);
544 static DEVICE_ATTR_RW(fan1_target);
545 static DEVICE_ATTR_RW(fan1_div);
546 static DEVICE_ATTR_RW(pwm1_enable);
547 static DEVICE_ATTR_RW(pwm1);
548 static SENSOR_DEVICE_ATTR_RO(fan1_max_alarm, alarm, MAX6650_ALRM_MAX);
549 static SENSOR_DEVICE_ATTR_RO(fan1_min_alarm, alarm, MAX6650_ALRM_MIN);
550 static SENSOR_DEVICE_ATTR_RO(fan1_fault, alarm, MAX6650_ALRM_TACH);
551 static SENSOR_DEVICE_ATTR_RO(gpio1_alarm, alarm, MAX6650_ALRM_GPIO1);
552 static SENSOR_DEVICE_ATTR_RO(gpio2_alarm, alarm, MAX6650_ALRM_GPIO2);
554 static umode_t max6650_attrs_visible(struct kobject *kobj, struct attribute *a,
557 struct device *dev = container_of(kobj, struct device, kobj);
558 struct max6650_data *data = dev_get_drvdata(dev);
559 struct i2c_client *client = data->client;
560 u8 alarm_en = i2c_smbus_read_byte_data(client, MAX6650_REG_ALARM_EN);
561 struct device_attribute *devattr;
564 * Hide the alarms that have not been enabled by the firmware
567 devattr = container_of(a, struct device_attribute, attr);
568 if (devattr == &sensor_dev_attr_fan1_max_alarm.dev_attr
569 || devattr == &sensor_dev_attr_fan1_min_alarm.dev_attr
570 || devattr == &sensor_dev_attr_fan1_fault.dev_attr
571 || devattr == &sensor_dev_attr_gpio1_alarm.dev_attr
572 || devattr == &sensor_dev_attr_gpio2_alarm.dev_attr) {
573 if (!(alarm_en & to_sensor_dev_attr(devattr)->index))
580 static struct attribute *max6650_attrs[] = {
581 &sensor_dev_attr_fan1_input.dev_attr.attr,
582 &dev_attr_fan1_target.attr,
583 &dev_attr_fan1_div.attr,
584 &dev_attr_pwm1_enable.attr,
586 &sensor_dev_attr_fan1_max_alarm.dev_attr.attr,
587 &sensor_dev_attr_fan1_min_alarm.dev_attr.attr,
588 &sensor_dev_attr_fan1_fault.dev_attr.attr,
589 &sensor_dev_attr_gpio1_alarm.dev_attr.attr,
590 &sensor_dev_attr_gpio2_alarm.dev_attr.attr,
594 static const struct attribute_group max6650_group = {
595 .attrs = max6650_attrs,
596 .is_visible = max6650_attrs_visible,
599 static struct attribute *max6651_attrs[] = {
600 &sensor_dev_attr_fan2_input.dev_attr.attr,
601 &sensor_dev_attr_fan3_input.dev_attr.attr,
602 &sensor_dev_attr_fan4_input.dev_attr.attr,
606 static const struct attribute_group max6651_group = {
607 .attrs = max6651_attrs,
614 static int max6650_init_client(struct max6650_data *data,
615 struct i2c_client *client)
617 struct device *dev = &client->dev;
624 if (of_property_read_u32(dev->of_node, "maxim,fan-microvolt",
626 voltage = fan_voltage;
628 voltage /= 1000000; /* Microvolts to volts */
629 if (of_property_read_u32(dev->of_node, "maxim,fan-prescale",
631 prescale = prescaler;
633 config = i2c_smbus_read_byte_data(client, MAX6650_REG_CONFIG);
636 dev_err(dev, "Error reading config, aborting.\n");
644 config &= ~MAX6650_CFG_V12;
647 config |= MAX6650_CFG_V12;
650 dev_err(dev, "illegal value for fan_voltage (%d)\n", voltage);
657 config &= ~MAX6650_CFG_PRESCALER_MASK;
660 config = (config & ~MAX6650_CFG_PRESCALER_MASK)
661 | MAX6650_CFG_PRESCALER_2;
664 config = (config & ~MAX6650_CFG_PRESCALER_MASK)
665 | MAX6650_CFG_PRESCALER_4;
668 config = (config & ~MAX6650_CFG_PRESCALER_MASK)
669 | MAX6650_CFG_PRESCALER_8;
672 config = (config & ~MAX6650_CFG_PRESCALER_MASK)
673 | MAX6650_CFG_PRESCALER_16;
676 dev_err(dev, "illegal value for prescaler (%d)\n", prescale);
679 dev_info(dev, "Fan voltage: %dV, prescaler: %d.\n",
680 (config & MAX6650_CFG_V12) ? 12 : 5,
681 1 << (config & MAX6650_CFG_PRESCALER_MASK));
683 if (i2c_smbus_write_byte_data(client, MAX6650_REG_CONFIG, config)) {
684 dev_err(dev, "Config write error, aborting.\n");
688 data->config = config;
689 data->count = i2c_smbus_read_byte_data(client, MAX6650_REG_COUNT);
691 if (!of_property_read_u32(client->dev.of_node, "maxim,fan-target-rpm",
693 max6650_set_target(data, target_rpm);
694 max6650_set_operating_mode(data, MAX6650_CFG_MODE_CLOSED_LOOP);
700 #if IS_ENABLED(CONFIG_THERMAL)
702 static int max6650_get_max_state(struct thermal_cooling_device *cdev,
703 unsigned long *state)
710 static int max6650_get_cur_state(struct thermal_cooling_device *cdev,
711 unsigned long *state)
713 struct max6650_data *data = cdev->devdata;
715 *state = data->cooling_dev_state;
720 static int max6650_set_cur_state(struct thermal_cooling_device *cdev,
723 struct max6650_data *data = cdev->devdata;
724 struct i2c_client *client = data->client;
727 state = clamp_val(state, 0, 255);
729 mutex_lock(&data->update_lock);
731 if (data->config & MAX6650_CFG_V12)
732 data->dac = 180 - (180 * state)/255;
734 data->dac = 76 - (76 * state)/255;
736 err = i2c_smbus_write_byte_data(client, MAX6650_REG_DAC, data->dac);
739 max6650_set_operating_mode(data, state ?
740 MAX6650_CFG_MODE_OPEN_LOOP :
741 MAX6650_CFG_MODE_OFF);
742 data->cooling_dev_state = state;
745 mutex_unlock(&data->update_lock);
747 return err < 0 ? err : 0;
750 static const struct thermal_cooling_device_ops max6650_cooling_ops = {
751 .get_max_state = max6650_get_max_state,
752 .get_cur_state = max6650_get_cur_state,
753 .set_cur_state = max6650_set_cur_state,
757 static int max6650_probe(struct i2c_client *client,
758 const struct i2c_device_id *id)
760 struct device *dev = &client->dev;
761 const struct of_device_id *of_id =
762 of_match_device(of_match_ptr(max6650_dt_match), dev);
763 struct max6650_data *data;
764 struct device *hwmon_dev;
767 data = devm_kzalloc(dev, sizeof(struct max6650_data), GFP_KERNEL);
771 data->client = client;
772 i2c_set_clientdata(client, data);
773 mutex_init(&data->update_lock);
774 data->nr_fans = of_id ? (int)(uintptr_t)of_id->data : id->driver_data;
777 * Initialize the max6650 chip
779 err = max6650_init_client(data, client);
783 data->groups[0] = &max6650_group;
784 /* 3 additional fan inputs for the MAX6651 */
785 if (data->nr_fans == 4)
786 data->groups[1] = &max6651_group;
788 hwmon_dev = devm_hwmon_device_register_with_groups(dev,
791 err = PTR_ERR_OR_ZERO(hwmon_dev);
795 #if IS_ENABLED(CONFIG_THERMAL)
797 thermal_of_cooling_device_register(client->dev.of_node,
799 &max6650_cooling_ops);
800 if (IS_ERR(data->cooling_dev))
801 dev_warn(&client->dev,
802 "thermal cooling device register failed: %ld\n",
803 PTR_ERR(data->cooling_dev));
808 static int max6650_remove(struct i2c_client *client)
810 struct max6650_data *data = i2c_get_clientdata(client);
812 if (!IS_ERR(data->cooling_dev))
813 thermal_cooling_device_unregister(data->cooling_dev);
818 static const struct i2c_device_id max6650_id[] = {
823 MODULE_DEVICE_TABLE(i2c, max6650_id);
825 static struct i2c_driver max6650_driver = {
828 .of_match_table = of_match_ptr(max6650_dt_match),
830 .probe = max6650_probe,
831 .remove = max6650_remove,
832 .id_table = max6650_id,
835 module_i2c_driver(max6650_driver);
837 MODULE_AUTHOR("Hans J. Koch");
838 MODULE_DESCRIPTION("MAX6650 sensor driver");
839 MODULE_LICENSE("GPL");