2 * max6650.c - Part of lm_sensors, Linux kernel modules for hardware
5 * (C) 2007 by Hans J. Koch <hjk@linutronix.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 * Tha 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>
44 * Addresses to scan. There are four disjoint possibilities, by pin config.
47 static const unsigned short normal_i2c[] = {0x1b, 0x1f, 0x48, 0x4b,
54 /* fan_voltage: 5=5V fan, 12=12V fan, 0=don't change */
55 static int fan_voltage;
56 /* prescaler: Possible values are 1, 2, 4, 8, 16 or 0 for don't change */
58 /* clock: The clock frequency of the chip the driver should assume */
59 static int clock = 254000;
61 module_param(fan_voltage, int, S_IRUGO);
62 module_param(prescaler, int, S_IRUGO);
63 module_param(clock, int, S_IRUGO);
65 I2C_CLIENT_INSMOD_1(max6650);
68 * MAX 6650/6651 registers
71 #define MAX6650_REG_SPEED 0x00
72 #define MAX6650_REG_CONFIG 0x02
73 #define MAX6650_REG_GPIO_DEF 0x04
74 #define MAX6650_REG_DAC 0x06
75 #define MAX6650_REG_ALARM_EN 0x08
76 #define MAX6650_REG_ALARM 0x0A
77 #define MAX6650_REG_TACH0 0x0C
78 #define MAX6650_REG_TACH1 0x0E
79 #define MAX6650_REG_TACH2 0x10
80 #define MAX6650_REG_TACH3 0x12
81 #define MAX6650_REG_GPIO_STAT 0x14
82 #define MAX6650_REG_COUNT 0x16
85 * Config register bits
88 #define MAX6650_CFG_V12 0x08
89 #define MAX6650_CFG_PRESCALER_MASK 0x07
90 #define MAX6650_CFG_PRESCALER_2 0x01
91 #define MAX6650_CFG_PRESCALER_4 0x02
92 #define MAX6650_CFG_PRESCALER_8 0x03
93 #define MAX6650_CFG_PRESCALER_16 0x04
94 #define MAX6650_CFG_MODE_MASK 0x30
95 #define MAX6650_CFG_MODE_ON 0x00
96 #define MAX6650_CFG_MODE_OFF 0x10
97 #define MAX6650_CFG_MODE_CLOSED_LOOP 0x20
98 #define MAX6650_CFG_MODE_OPEN_LOOP 0x30
99 #define MAX6650_COUNT_MASK 0x03
101 /* Minimum and maximum values of the FAN-RPM */
102 #define FAN_RPM_MIN 240
103 #define FAN_RPM_MAX 30000
105 #define DIV_FROM_REG(reg) (1 << (reg & 7))
107 static int max6650_probe(struct i2c_client *client,
108 const struct i2c_device_id *id);
109 static int max6650_detect(struct i2c_client *client, int kind,
110 struct i2c_board_info *info);
111 static int max6650_init_client(struct i2c_client *client);
112 static int max6650_remove(struct i2c_client *client);
113 static struct max6650_data *max6650_update_device(struct device *dev);
116 * Driver data (common to all clients)
119 static const struct i2c_device_id max6650_id[] = {
120 { "max6650", max6650 },
123 MODULE_DEVICE_TABLE(i2c, max6650_id);
125 static struct i2c_driver max6650_driver = {
126 .class = I2C_CLASS_HWMON,
130 .probe = max6650_probe,
131 .remove = max6650_remove,
132 .id_table = max6650_id,
133 .detect = max6650_detect,
134 .address_data = &addr_data,
138 * Client data (each client gets its own)
143 struct device *hwmon_dev;
144 struct mutex update_lock;
145 char valid; /* zero until following fields are valid */
146 unsigned long last_updated; /* in jiffies */
148 /* register values */
156 static ssize_t get_fan(struct device *dev, struct device_attribute *devattr,
159 struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
160 struct max6650_data *data = max6650_update_device(dev);
164 * Calculation details:
166 * Each tachometer counts over an interval given by the "count"
167 * register (0.25, 0.5, 1 or 2 seconds). This module assumes
168 * that the fans produce two pulses per revolution (this seems
169 * to be the most common).
172 rpm = ((data->tach[attr->index] * 120) / DIV_FROM_REG(data->count));
173 return sprintf(buf, "%d\n", rpm);
177 * Set the fan speed to the specified RPM (or read back the RPM setting).
178 * This works in closed loop mode only. Use pwm1 for open loop speed setting.
180 * The MAX6650/1 will automatically control fan speed when in closed loop
185 * 1) The MAX6650/1 internal 254kHz clock frequency is set correctly. Use
186 * the clock module parameter if you need to fine tune this.
188 * 2) The prescaler (low three bits of the config register) has already
189 * been set to an appropriate value. Use the prescaler module parameter
190 * if your BIOS doesn't initialize the chip properly.
192 * The relevant equations are given on pages 21 and 22 of the datasheet.
194 * From the datasheet, the relevant equation when in regulation is:
196 * [fCLK / (128 x (KTACH + 1))] = 2 x FanSpeed / KSCALE
200 * fCLK is the oscillator frequency (either the 254kHz internal
201 * oscillator or the externally applied clock)
203 * KTACH is the value in the speed register
205 * FanSpeed is the speed of the fan in rps
207 * KSCALE is the prescaler value (1, 2, 4, 8, or 16)
209 * When reading, we need to solve for FanSpeed. When writing, we need to
212 * Note: this tachometer is completely separate from the tachometers
213 * used to measure the fan speeds. Only one fan's speed (fan1) is
217 static ssize_t get_target(struct device *dev, struct device_attribute *devattr,
220 struct max6650_data *data = max6650_update_device(dev);
221 int kscale, ktach, rpm;
224 * Use the datasheet equation:
226 * FanSpeed = KSCALE x fCLK / [256 x (KTACH + 1)]
228 * then multiply by 60 to give rpm.
231 kscale = DIV_FROM_REG(data->config);
233 rpm = 60 * kscale * clock / (256 * (ktach + 1));
234 return sprintf(buf, "%d\n", rpm);
237 static ssize_t set_target(struct device *dev, struct device_attribute *devattr,
238 const char *buf, size_t count)
240 struct i2c_client *client = to_i2c_client(dev);
241 struct max6650_data *data = i2c_get_clientdata(client);
242 int rpm = simple_strtoul(buf, NULL, 10);
245 rpm = SENSORS_LIMIT(rpm, FAN_RPM_MIN, FAN_RPM_MAX);
248 * Divide the required speed by 60 to get from rpm to rps, then
249 * use the datasheet equation:
251 * KTACH = [(fCLK x KSCALE) / (256 x FanSpeed)] - 1
254 mutex_lock(&data->update_lock);
256 kscale = DIV_FROM_REG(data->config);
257 ktach = ((clock * kscale) / (256 * rpm / 60)) - 1;
264 i2c_smbus_write_byte_data(client, MAX6650_REG_SPEED, data->speed);
266 mutex_unlock(&data->update_lock);
272 * Get/set the fan speed in open loop mode using pwm1 sysfs file.
273 * Speed is given as a relative value from 0 to 255, where 255 is maximum
274 * speed. Note that this is done by writing directly to the chip's DAC,
275 * it won't change the closed loop speed set by fan1_target.
276 * Also note that due to rounding errors it is possible that you don't read
277 * back exactly the value you have set.
280 static ssize_t get_pwm(struct device *dev, struct device_attribute *devattr,
284 struct max6650_data *data = max6650_update_device(dev);
286 /* Useful range for dac is 0-180 for 12V fans and 0-76 for 5V fans.
287 Lower DAC values mean higher speeds. */
288 if (data->config & MAX6650_CFG_V12)
289 pwm = 255 - (255 * (int)data->dac)/180;
291 pwm = 255 - (255 * (int)data->dac)/76;
296 return sprintf(buf, "%d\n", pwm);
299 static ssize_t set_pwm(struct device *dev, struct device_attribute *devattr,
300 const char *buf, size_t count)
302 struct i2c_client *client = to_i2c_client(dev);
303 struct max6650_data *data = i2c_get_clientdata(client);
304 int pwm = simple_strtoul(buf, NULL, 10);
306 pwm = SENSORS_LIMIT(pwm, 0, 255);
308 mutex_lock(&data->update_lock);
310 if (data->config & MAX6650_CFG_V12)
311 data->dac = 180 - (180 * pwm)/255;
313 data->dac = 76 - (76 * pwm)/255;
315 i2c_smbus_write_byte_data(client, MAX6650_REG_DAC, data->dac);
317 mutex_unlock(&data->update_lock);
323 * Get/Set controller mode:
326 * 1 = Open loop, Voltage is set according to speed, not regulated.
327 * 2 = Closed loop, RPM for all fans regulated by fan1 tachometer
330 static ssize_t get_enable(struct device *dev, struct device_attribute *devattr,
333 struct max6650_data *data = max6650_update_device(dev);
334 int mode = (data->config & MAX6650_CFG_MODE_MASK) >> 4;
335 int sysfs_modes[4] = {0, 1, 2, 1};
337 return sprintf(buf, "%d\n", sysfs_modes[mode]);
340 static ssize_t set_enable(struct device *dev, struct device_attribute *devattr,
341 const char *buf, size_t count)
343 struct i2c_client *client = to_i2c_client(dev);
344 struct max6650_data *data = i2c_get_clientdata(client);
345 int mode = simple_strtoul(buf, NULL, 10);
346 int max6650_modes[3] = {0, 3, 2};
348 if ((mode < 0)||(mode > 2)) {
349 dev_err(&client->dev,
350 "illegal value for pwm1_enable (%d)\n", mode);
354 mutex_lock(&data->update_lock);
356 data->config = i2c_smbus_read_byte_data(client, MAX6650_REG_CONFIG);
357 data->config = (data->config & ~MAX6650_CFG_MODE_MASK)
358 | (max6650_modes[mode] << 4);
360 i2c_smbus_write_byte_data(client, MAX6650_REG_CONFIG, data->config);
362 mutex_unlock(&data->update_lock);
368 * Read/write functions for fan1_div sysfs file. The MAX6650 has no such
369 * divider. We handle this by converting between divider and counttime:
371 * (counttime == k) <==> (divider == 2^k), k = 0, 1, 2, or 3
373 * Lower values of k allow to connect a faster fan without the risk of
374 * counter overflow. The price is lower resolution. You can also set counttime
375 * using the module parameter. Note that the module parameter "prescaler" also
376 * influences the behaviour. Unfortunately, there's no sysfs attribute
377 * defined for that. See the data sheet for details.
380 static ssize_t get_div(struct device *dev, struct device_attribute *devattr,
383 struct max6650_data *data = max6650_update_device(dev);
385 return sprintf(buf, "%d\n", DIV_FROM_REG(data->count));
388 static ssize_t set_div(struct device *dev, struct device_attribute *devattr,
389 const char *buf, size_t count)
391 struct i2c_client *client = to_i2c_client(dev);
392 struct max6650_data *data = i2c_get_clientdata(client);
393 int div = simple_strtoul(buf, NULL, 10);
395 mutex_lock(&data->update_lock);
410 dev_err(&client->dev,
411 "illegal value for fan divider (%d)\n", div);
415 i2c_smbus_write_byte_data(client, MAX6650_REG_COUNT, data->count);
416 mutex_unlock(&data->update_lock);
421 static SENSOR_DEVICE_ATTR(fan1_input, S_IRUGO, get_fan, NULL, 0);
422 static SENSOR_DEVICE_ATTR(fan2_input, S_IRUGO, get_fan, NULL, 1);
423 static SENSOR_DEVICE_ATTR(fan3_input, S_IRUGO, get_fan, NULL, 2);
424 static SENSOR_DEVICE_ATTR(fan4_input, S_IRUGO, get_fan, NULL, 3);
425 static DEVICE_ATTR(fan1_target, S_IWUSR | S_IRUGO, get_target, set_target);
426 static DEVICE_ATTR(fan1_div, S_IWUSR | S_IRUGO, get_div, set_div);
427 static DEVICE_ATTR(pwm1_enable, S_IWUSR | S_IRUGO, get_enable, set_enable);
428 static DEVICE_ATTR(pwm1, S_IWUSR | S_IRUGO, get_pwm, set_pwm);
431 static struct attribute *max6650_attrs[] = {
432 &sensor_dev_attr_fan1_input.dev_attr.attr,
433 &sensor_dev_attr_fan2_input.dev_attr.attr,
434 &sensor_dev_attr_fan3_input.dev_attr.attr,
435 &sensor_dev_attr_fan4_input.dev_attr.attr,
436 &dev_attr_fan1_target.attr,
437 &dev_attr_fan1_div.attr,
438 &dev_attr_pwm1_enable.attr,
443 static struct attribute_group max6650_attr_grp = {
444 .attrs = max6650_attrs,
451 /* Return 0 if detection is successful, -ENODEV otherwise */
452 static int max6650_detect(struct i2c_client *client, int kind,
453 struct i2c_board_info *info)
455 struct i2c_adapter *adapter = client->adapter;
456 int address = client->addr;
458 dev_dbg(&adapter->dev, "max6650_detect called, kind = %d\n", kind);
460 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA)) {
461 dev_dbg(&adapter->dev, "max6650: I2C bus doesn't support "
462 "byte read mode, skipping.\n");
467 * Now we do the remaining detection. A negative kind means that
468 * the driver was loaded with no force parameter (default), so we
469 * must both detect and identify the chip (actually there is only
470 * one possible kind of chip for now, max6650). A zero kind means that
471 * the driver was loaded with the force parameter, the detection
472 * step shall be skipped. A positive kind means that the driver
473 * was loaded with the force parameter and a given kind of chip is
474 * requested, so both the detection and the identification steps
477 * Currently I can find no way to distinguish between a MAX6650 and
478 * a MAX6651. This driver has only been tried on the former.
482 ( (i2c_smbus_read_byte_data(client, MAX6650_REG_CONFIG) & 0xC0)
483 ||(i2c_smbus_read_byte_data(client, MAX6650_REG_GPIO_STAT) & 0xE0)
484 ||(i2c_smbus_read_byte_data(client, MAX6650_REG_ALARM_EN) & 0xE0)
485 ||(i2c_smbus_read_byte_data(client, MAX6650_REG_ALARM) & 0xE0)
486 ||(i2c_smbus_read_byte_data(client, MAX6650_REG_COUNT) & 0xFC))) {
487 dev_dbg(&adapter->dev,
488 "max6650: detection failed at 0x%02x.\n", address);
492 dev_info(&adapter->dev, "max6650: chip found at 0x%02x.\n", address);
494 strlcpy(info->type, "max6650", I2C_NAME_SIZE);
499 static int max6650_probe(struct i2c_client *client,
500 const struct i2c_device_id *id)
502 struct max6650_data *data;
505 if (!(data = kzalloc(sizeof(struct max6650_data), GFP_KERNEL))) {
506 dev_err(&client->dev, "out of memory.\n");
510 i2c_set_clientdata(client, data);
511 mutex_init(&data->update_lock);
514 * Initialize the max6650 chip
516 err = max6650_init_client(client);
520 err = sysfs_create_group(&client->dev.kobj, &max6650_attr_grp);
524 data->hwmon_dev = hwmon_device_register(&client->dev);
525 if (!IS_ERR(data->hwmon_dev))
528 err = PTR_ERR(data->hwmon_dev);
529 dev_err(&client->dev, "error registering hwmon device.\n");
530 sysfs_remove_group(&client->dev.kobj, &max6650_attr_grp);
536 static int max6650_remove(struct i2c_client *client)
538 struct max6650_data *data = i2c_get_clientdata(client);
540 sysfs_remove_group(&client->dev.kobj, &max6650_attr_grp);
541 hwmon_device_unregister(data->hwmon_dev);
546 static int max6650_init_client(struct i2c_client *client)
548 struct max6650_data *data = i2c_get_clientdata(client);
552 config = i2c_smbus_read_byte_data(client, MAX6650_REG_CONFIG);
555 dev_err(&client->dev, "Error reading config, aborting.\n");
559 switch (fan_voltage) {
563 config &= ~MAX6650_CFG_V12;
566 config |= MAX6650_CFG_V12;
569 dev_err(&client->dev,
570 "illegal value for fan_voltage (%d)\n",
574 dev_info(&client->dev, "Fan voltage is set to %dV.\n",
575 (config & MAX6650_CFG_V12) ? 12 : 5);
581 config &= ~MAX6650_CFG_PRESCALER_MASK;
584 config = (config & ~MAX6650_CFG_PRESCALER_MASK)
585 | MAX6650_CFG_PRESCALER_2;
588 config = (config & ~MAX6650_CFG_PRESCALER_MASK)
589 | MAX6650_CFG_PRESCALER_4;
592 config = (config & ~MAX6650_CFG_PRESCALER_MASK)
593 | MAX6650_CFG_PRESCALER_8;
596 config = (config & ~MAX6650_CFG_PRESCALER_MASK)
597 | MAX6650_CFG_PRESCALER_16;
600 dev_err(&client->dev,
601 "illegal value for prescaler (%d)\n",
605 dev_info(&client->dev, "Prescaler is set to %d.\n",
606 1 << (config & MAX6650_CFG_PRESCALER_MASK));
608 /* If mode is set to "full off", we change it to "open loop" and
609 * set DAC to 255, which has the same effect. We do this because
610 * there's no "full off" mode defined in hwmon specifcations.
613 if ((config & MAX6650_CFG_MODE_MASK) == MAX6650_CFG_MODE_OFF) {
614 dev_dbg(&client->dev, "Change mode to open loop, full off.\n");
615 config = (config & ~MAX6650_CFG_MODE_MASK)
616 | MAX6650_CFG_MODE_OPEN_LOOP;
617 if (i2c_smbus_write_byte_data(client, MAX6650_REG_DAC, 255)) {
618 dev_err(&client->dev, "DAC write error, aborting.\n");
623 if (i2c_smbus_write_byte_data(client, MAX6650_REG_CONFIG, config)) {
624 dev_err(&client->dev, "Config write error, aborting.\n");
628 data->config = config;
629 data->count = i2c_smbus_read_byte_data(client, MAX6650_REG_COUNT);
634 static const u8 tach_reg[] = {
641 static struct max6650_data *max6650_update_device(struct device *dev)
644 struct i2c_client *client = to_i2c_client(dev);
645 struct max6650_data *data = i2c_get_clientdata(client);
647 mutex_lock(&data->update_lock);
649 if (time_after(jiffies, data->last_updated + HZ) || !data->valid) {
650 data->speed = i2c_smbus_read_byte_data(client,
652 data->config = i2c_smbus_read_byte_data(client,
654 for (i = 0; i < 4; i++) {
655 data->tach[i] = i2c_smbus_read_byte_data(client,
658 data->count = i2c_smbus_read_byte_data(client,
660 data->dac = i2c_smbus_read_byte_data(client, MAX6650_REG_DAC);
662 data->last_updated = jiffies;
666 mutex_unlock(&data->update_lock);
671 static int __init sensors_max6650_init(void)
673 return i2c_add_driver(&max6650_driver);
676 static void __exit sensors_max6650_exit(void)
678 i2c_del_driver(&max6650_driver);
681 MODULE_AUTHOR("Hans J. Koch");
682 MODULE_DESCRIPTION("MAX6650 sensor driver");
683 MODULE_LICENSE("GPL");
685 module_init(sensors_max6650_init);
686 module_exit(sensors_max6650_exit);