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>
48 /* fan_voltage: 5=5V fan, 12=12V fan, 0=don't change */
49 static int fan_voltage;
50 /* prescaler: Possible values are 1, 2, 4, 8, 16 or 0 for don't change */
52 /* clock: The clock frequency of the chip (max6651 can be clocked externally) */
53 static int clock = 254000;
55 module_param(fan_voltage, int, S_IRUGO);
56 module_param(prescaler, int, S_IRUGO);
57 module_param(clock, int, S_IRUGO);
60 * MAX 6650/6651 registers
63 #define MAX6650_REG_SPEED 0x00
64 #define MAX6650_REG_CONFIG 0x02
65 #define MAX6650_REG_GPIO_DEF 0x04
66 #define MAX6650_REG_DAC 0x06
67 #define MAX6650_REG_ALARM_EN 0x08
68 #define MAX6650_REG_ALARM 0x0A
69 #define MAX6650_REG_TACH0 0x0C
70 #define MAX6650_REG_TACH1 0x0E
71 #define MAX6650_REG_TACH2 0x10
72 #define MAX6650_REG_TACH3 0x12
73 #define MAX6650_REG_GPIO_STAT 0x14
74 #define MAX6650_REG_COUNT 0x16
77 * Config register bits
80 #define MAX6650_CFG_V12 0x08
81 #define MAX6650_CFG_PRESCALER_MASK 0x07
82 #define MAX6650_CFG_PRESCALER_2 0x01
83 #define MAX6650_CFG_PRESCALER_4 0x02
84 #define MAX6650_CFG_PRESCALER_8 0x03
85 #define MAX6650_CFG_PRESCALER_16 0x04
86 #define MAX6650_CFG_MODE_MASK 0x30
87 #define MAX6650_CFG_MODE_ON 0x00
88 #define MAX6650_CFG_MODE_OFF 0x10
89 #define MAX6650_CFG_MODE_CLOSED_LOOP 0x20
90 #define MAX6650_CFG_MODE_OPEN_LOOP 0x30
91 #define MAX6650_COUNT_MASK 0x03
94 * Alarm status register bits
97 #define MAX6650_ALRM_MAX 0x01
98 #define MAX6650_ALRM_MIN 0x02
99 #define MAX6650_ALRM_TACH 0x04
100 #define MAX6650_ALRM_GPIO1 0x08
101 #define MAX6650_ALRM_GPIO2 0x10
103 /* Minimum and maximum values of the FAN-RPM */
104 #define FAN_RPM_MIN 240
105 #define FAN_RPM_MAX 30000
107 #define DIV_FROM_REG(reg) (1 << (reg & 7))
110 * Client data (each client gets its own)
113 struct max6650_data {
114 struct i2c_client *client;
115 const struct attribute_group *groups[3];
116 struct mutex update_lock;
118 char valid; /* zero until following fields are valid */
119 unsigned long last_updated; /* in jiffies */
121 /* register values */
130 static const u8 tach_reg[] = {
137 static const struct of_device_id max6650_dt_match[] = {
139 .compatible = "maxim,max6650",
143 .compatible = "maxim,max6651",
148 MODULE_DEVICE_TABLE(of, max6650_dt_match);
150 static struct max6650_data *max6650_update_device(struct device *dev)
152 struct max6650_data *data = dev_get_drvdata(dev);
153 struct i2c_client *client = data->client;
156 mutex_lock(&data->update_lock);
158 if (time_after(jiffies, data->last_updated + HZ) || !data->valid) {
159 data->speed = i2c_smbus_read_byte_data(client,
161 data->config = i2c_smbus_read_byte_data(client,
163 for (i = 0; i < data->nr_fans; i++) {
164 data->tach[i] = i2c_smbus_read_byte_data(client,
167 data->count = i2c_smbus_read_byte_data(client,
169 data->dac = i2c_smbus_read_byte_data(client, MAX6650_REG_DAC);
172 * Alarms are cleared on read in case the condition that
173 * caused the alarm is removed. Keep the value latched here
174 * for providing the register through different alarm files.
176 data->alarm |= i2c_smbus_read_byte_data(client,
179 data->last_updated = jiffies;
183 mutex_unlock(&data->update_lock);
189 * Change the operating mode of the chip (if needed).
190 * mode is one of the MAX6650_CFG_MODE_* values.
192 static int max6650_set_operating_mode(struct max6650_data *data, u8 mode)
195 u8 config = data->config;
197 if (mode == (config & MAX6650_CFG_MODE_MASK))
200 config = (config & ~MAX6650_CFG_MODE_MASK) | mode;
202 result = i2c_smbus_write_byte_data(data->client, MAX6650_REG_CONFIG,
207 data->config = config;
212 static ssize_t get_fan(struct device *dev, struct device_attribute *devattr,
215 struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
216 struct max6650_data *data = max6650_update_device(dev);
220 * Calculation details:
222 * Each tachometer counts over an interval given by the "count"
223 * register (0.25, 0.5, 1 or 2 seconds). This module assumes
224 * that the fans produce two pulses per revolution (this seems
225 * to be the most common).
228 rpm = ((data->tach[attr->index] * 120) / DIV_FROM_REG(data->count));
229 return sprintf(buf, "%d\n", rpm);
233 * Set the fan speed to the specified RPM (or read back the RPM setting).
234 * This works in closed loop mode only. Use pwm1 for open loop speed setting.
236 * The MAX6650/1 will automatically control fan speed when in closed loop
241 * 1) The MAX6650/1 internal 254kHz clock frequency is set correctly. Use
242 * the clock module parameter if you need to fine tune this.
244 * 2) The prescaler (low three bits of the config register) has already
245 * been set to an appropriate value. Use the prescaler module parameter
246 * if your BIOS doesn't initialize the chip properly.
248 * The relevant equations are given on pages 21 and 22 of the datasheet.
250 * From the datasheet, the relevant equation when in regulation is:
252 * [fCLK / (128 x (KTACH + 1))] = 2 x FanSpeed / KSCALE
256 * fCLK is the oscillator frequency (either the 254kHz internal
257 * oscillator or the externally applied clock)
259 * KTACH is the value in the speed register
261 * FanSpeed is the speed of the fan in rps
263 * KSCALE is the prescaler value (1, 2, 4, 8, or 16)
265 * When reading, we need to solve for FanSpeed. When writing, we need to
268 * Note: this tachometer is completely separate from the tachometers
269 * used to measure the fan speeds. Only one fan's speed (fan1) is
273 static ssize_t get_target(struct device *dev, struct device_attribute *devattr,
276 struct max6650_data *data = max6650_update_device(dev);
277 int kscale, ktach, rpm;
280 * Use the datasheet equation:
282 * FanSpeed = KSCALE x fCLK / [256 x (KTACH + 1)]
284 * then multiply by 60 to give rpm.
287 kscale = DIV_FROM_REG(data->config);
289 rpm = 60 * kscale * clock / (256 * (ktach + 1));
290 return sprintf(buf, "%d\n", rpm);
293 static int max6650_set_target(struct max6650_data *data, unsigned long rpm)
298 return max6650_set_operating_mode(data, MAX6650_CFG_MODE_OFF);
300 rpm = clamp_val(rpm, FAN_RPM_MIN, FAN_RPM_MAX);
303 * Divide the required speed by 60 to get from rpm to rps, then
304 * use the datasheet equation:
306 * KTACH = [(fCLK x KSCALE) / (256 x FanSpeed)] - 1
309 kscale = DIV_FROM_REG(data->config);
310 ktach = ((clock * kscale) / (256 * rpm / 60)) - 1;
317 return i2c_smbus_write_byte_data(data->client, MAX6650_REG_SPEED,
321 static ssize_t set_target(struct device *dev, struct device_attribute *devattr,
322 const char *buf, size_t count)
324 struct max6650_data *data = dev_get_drvdata(dev);
328 err = kstrtoul(buf, 10, &rpm);
332 mutex_lock(&data->update_lock);
334 err = max6650_set_target(data, rpm);
336 mutex_unlock(&data->update_lock);
345 * Get/set the fan speed in open loop mode using pwm1 sysfs file.
346 * Speed is given as a relative value from 0 to 255, where 255 is maximum
347 * speed. Note that this is done by writing directly to the chip's DAC,
348 * it won't change the closed loop speed set by fan1_target.
349 * Also note that due to rounding errors it is possible that you don't read
350 * back exactly the value you have set.
353 static ssize_t get_pwm(struct device *dev, struct device_attribute *devattr,
357 struct max6650_data *data = max6650_update_device(dev);
360 * Useful range for dac is 0-180 for 12V fans and 0-76 for 5V fans.
361 * Lower DAC values mean higher speeds.
363 if (data->config & MAX6650_CFG_V12)
364 pwm = 255 - (255 * (int)data->dac)/180;
366 pwm = 255 - (255 * (int)data->dac)/76;
371 return sprintf(buf, "%d\n", pwm);
374 static ssize_t set_pwm(struct device *dev, struct device_attribute *devattr,
375 const char *buf, size_t count)
377 struct max6650_data *data = dev_get_drvdata(dev);
378 struct i2c_client *client = data->client;
382 err = kstrtoul(buf, 10, &pwm);
386 pwm = clamp_val(pwm, 0, 255);
388 mutex_lock(&data->update_lock);
390 if (data->config & MAX6650_CFG_V12)
391 data->dac = 180 - (180 * pwm)/255;
393 data->dac = 76 - (76 * pwm)/255;
394 err = i2c_smbus_write_byte_data(client, MAX6650_REG_DAC, data->dac);
396 mutex_unlock(&data->update_lock);
398 return err < 0 ? err : count;
402 * Get/Set controller mode:
405 * 1 = Open loop, Voltage is set according to speed, not regulated.
406 * 2 = Closed loop, RPM for all fans regulated by fan1 tachometer
409 static ssize_t get_enable(struct device *dev, struct device_attribute *devattr,
412 struct max6650_data *data = max6650_update_device(dev);
413 int mode = (data->config & MAX6650_CFG_MODE_MASK) >> 4;
414 int sysfs_modes[4] = {0, 3, 2, 1};
416 return sprintf(buf, "%d\n", sysfs_modes[mode]);
419 static ssize_t set_enable(struct device *dev, struct device_attribute *devattr,
420 const char *buf, size_t count)
422 struct max6650_data *data = dev_get_drvdata(dev);
425 const u8 max6650_modes[] = {
427 MAX6650_CFG_MODE_OPEN_LOOP,
428 MAX6650_CFG_MODE_CLOSED_LOOP,
429 MAX6650_CFG_MODE_OFF,
432 err = kstrtoul(buf, 10, &mode);
436 if (mode >= ARRAY_SIZE(max6650_modes))
439 mutex_lock(&data->update_lock);
441 max6650_set_operating_mode(data, max6650_modes[mode]);
443 mutex_unlock(&data->update_lock);
449 * Read/write functions for fan1_div sysfs file. The MAX6650 has no such
450 * divider. We handle this by converting between divider and counttime:
452 * (counttime == k) <==> (divider == 2^k), k = 0, 1, 2, or 3
454 * Lower values of k allow to connect a faster fan without the risk of
455 * counter overflow. The price is lower resolution. You can also set counttime
456 * using the module parameter. Note that the module parameter "prescaler" also
457 * influences the behaviour. Unfortunately, there's no sysfs attribute
458 * defined for that. See the data sheet for details.
461 static ssize_t get_div(struct device *dev, struct device_attribute *devattr,
464 struct max6650_data *data = max6650_update_device(dev);
466 return sprintf(buf, "%d\n", DIV_FROM_REG(data->count));
469 static ssize_t set_div(struct device *dev, struct device_attribute *devattr,
470 const char *buf, size_t count)
472 struct max6650_data *data = dev_get_drvdata(dev);
473 struct i2c_client *client = data->client;
477 err = kstrtoul(buf, 10, &div);
481 mutex_lock(&data->update_lock);
496 mutex_unlock(&data->update_lock);
500 i2c_smbus_write_byte_data(client, MAX6650_REG_COUNT, data->count);
501 mutex_unlock(&data->update_lock);
513 static ssize_t get_alarm(struct device *dev, struct device_attribute *devattr,
516 struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
517 struct max6650_data *data = max6650_update_device(dev);
518 struct i2c_client *client = data->client;
521 if (data->alarm & attr->index) {
522 mutex_lock(&data->update_lock);
524 data->alarm &= ~attr->index;
525 data->alarm |= i2c_smbus_read_byte_data(client,
527 mutex_unlock(&data->update_lock);
530 return sprintf(buf, "%d\n", alarm);
533 static SENSOR_DEVICE_ATTR(fan1_input, S_IRUGO, get_fan, NULL, 0);
534 static SENSOR_DEVICE_ATTR(fan2_input, S_IRUGO, get_fan, NULL, 1);
535 static SENSOR_DEVICE_ATTR(fan3_input, S_IRUGO, get_fan, NULL, 2);
536 static SENSOR_DEVICE_ATTR(fan4_input, S_IRUGO, get_fan, NULL, 3);
537 static DEVICE_ATTR(fan1_target, S_IWUSR | S_IRUGO, get_target, set_target);
538 static DEVICE_ATTR(fan1_div, S_IWUSR | S_IRUGO, get_div, set_div);
539 static DEVICE_ATTR(pwm1_enable, S_IWUSR | S_IRUGO, get_enable, set_enable);
540 static DEVICE_ATTR(pwm1, S_IWUSR | S_IRUGO, get_pwm, set_pwm);
541 static SENSOR_DEVICE_ATTR(fan1_max_alarm, S_IRUGO, get_alarm, NULL,
543 static SENSOR_DEVICE_ATTR(fan1_min_alarm, S_IRUGO, get_alarm, NULL,
545 static SENSOR_DEVICE_ATTR(fan1_fault, S_IRUGO, get_alarm, NULL,
547 static SENSOR_DEVICE_ATTR(gpio1_alarm, S_IRUGO, get_alarm, NULL,
549 static SENSOR_DEVICE_ATTR(gpio2_alarm, S_IRUGO, get_alarm, NULL,
552 static umode_t max6650_attrs_visible(struct kobject *kobj, struct attribute *a,
555 struct device *dev = container_of(kobj, struct device, kobj);
556 struct max6650_data *data = dev_get_drvdata(dev);
557 struct i2c_client *client = data->client;
558 u8 alarm_en = i2c_smbus_read_byte_data(client, MAX6650_REG_ALARM_EN);
559 struct device_attribute *devattr;
562 * Hide the alarms that have not been enabled by the firmware
565 devattr = container_of(a, struct device_attribute, attr);
566 if (devattr == &sensor_dev_attr_fan1_max_alarm.dev_attr
567 || devattr == &sensor_dev_attr_fan1_min_alarm.dev_attr
568 || devattr == &sensor_dev_attr_fan1_fault.dev_attr
569 || devattr == &sensor_dev_attr_gpio1_alarm.dev_attr
570 || devattr == &sensor_dev_attr_gpio2_alarm.dev_attr) {
571 if (!(alarm_en & to_sensor_dev_attr(devattr)->index))
578 static struct attribute *max6650_attrs[] = {
579 &sensor_dev_attr_fan1_input.dev_attr.attr,
580 &dev_attr_fan1_target.attr,
581 &dev_attr_fan1_div.attr,
582 &dev_attr_pwm1_enable.attr,
584 &sensor_dev_attr_fan1_max_alarm.dev_attr.attr,
585 &sensor_dev_attr_fan1_min_alarm.dev_attr.attr,
586 &sensor_dev_attr_fan1_fault.dev_attr.attr,
587 &sensor_dev_attr_gpio1_alarm.dev_attr.attr,
588 &sensor_dev_attr_gpio2_alarm.dev_attr.attr,
592 static const struct attribute_group max6650_group = {
593 .attrs = max6650_attrs,
594 .is_visible = max6650_attrs_visible,
597 static struct attribute *max6651_attrs[] = {
598 &sensor_dev_attr_fan2_input.dev_attr.attr,
599 &sensor_dev_attr_fan3_input.dev_attr.attr,
600 &sensor_dev_attr_fan4_input.dev_attr.attr,
604 static const struct attribute_group max6651_group = {
605 .attrs = max6651_attrs,
612 static int max6650_init_client(struct max6650_data *data,
613 struct i2c_client *client)
615 struct device *dev = &client->dev;
622 if (of_property_read_u32(dev->of_node, "maxim,fan-microvolt",
624 voltage = fan_voltage;
626 voltage /= 1000000; /* Microvolts to volts */
627 if (of_property_read_u32(dev->of_node, "maxim,fan-prescale",
629 prescale = prescaler;
631 config = i2c_smbus_read_byte_data(client, MAX6650_REG_CONFIG);
634 dev_err(dev, "Error reading config, aborting.\n");
642 config &= ~MAX6650_CFG_V12;
645 config |= MAX6650_CFG_V12;
648 dev_err(dev, "illegal value for fan_voltage (%d)\n", voltage);
655 config &= ~MAX6650_CFG_PRESCALER_MASK;
658 config = (config & ~MAX6650_CFG_PRESCALER_MASK)
659 | MAX6650_CFG_PRESCALER_2;
662 config = (config & ~MAX6650_CFG_PRESCALER_MASK)
663 | MAX6650_CFG_PRESCALER_4;
666 config = (config & ~MAX6650_CFG_PRESCALER_MASK)
667 | MAX6650_CFG_PRESCALER_8;
670 config = (config & ~MAX6650_CFG_PRESCALER_MASK)
671 | MAX6650_CFG_PRESCALER_16;
674 dev_err(dev, "illegal value for prescaler (%d)\n", prescale);
677 dev_info(dev, "Fan voltage: %dV, prescaler: %d.\n",
678 (config & MAX6650_CFG_V12) ? 12 : 5,
679 1 << (config & MAX6650_CFG_PRESCALER_MASK));
681 if (i2c_smbus_write_byte_data(client, MAX6650_REG_CONFIG, config)) {
682 dev_err(dev, "Config write error, aborting.\n");
686 data->config = config;
687 data->count = i2c_smbus_read_byte_data(client, MAX6650_REG_COUNT);
689 if (!of_property_read_u32(client->dev.of_node, "maxim,fan-target-rpm",
691 max6650_set_target(data, target_rpm);
692 max6650_set_operating_mode(data, MAX6650_CFG_MODE_CLOSED_LOOP);
698 static int max6650_probe(struct i2c_client *client,
699 const struct i2c_device_id *id)
701 struct device *dev = &client->dev;
702 const struct of_device_id *of_id =
703 of_match_device(of_match_ptr(max6650_dt_match), dev);
704 struct max6650_data *data;
705 struct device *hwmon_dev;
708 data = devm_kzalloc(dev, sizeof(struct max6650_data), GFP_KERNEL);
712 data->client = client;
713 mutex_init(&data->update_lock);
714 data->nr_fans = of_id ? (int)(uintptr_t)of_id->data : id->driver_data;
717 * Initialize the max6650 chip
719 err = max6650_init_client(data, client);
723 data->groups[0] = &max6650_group;
724 /* 3 additional fan inputs for the MAX6651 */
725 if (data->nr_fans == 4)
726 data->groups[1] = &max6651_group;
728 hwmon_dev = devm_hwmon_device_register_with_groups(dev,
731 return PTR_ERR_OR_ZERO(hwmon_dev);
734 static const struct i2c_device_id max6650_id[] = {
739 MODULE_DEVICE_TABLE(i2c, max6650_id);
741 static struct i2c_driver max6650_driver = {
744 .of_match_table = of_match_ptr(max6650_dt_match),
746 .probe = max6650_probe,
747 .id_table = max6650_id,
750 module_i2c_driver(max6650_driver);
752 MODULE_AUTHOR("Hans J. Koch");
753 MODULE_DESCRIPTION("MAX6650 sensor driver");
754 MODULE_LICENSE("GPL");