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* max6639.c - Support for Maxim MAX6639
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* 2-Channel Temperature Monitor with Dual PWM Fan-Speed Controller
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* Copyright (C) 2010, 2011 Roland Stigge <stigge@antcom.de>
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* based on the initial MAX6639 support from semptian.net
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* by He Changqing <hechangqing@semptian.com>
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/slab.h>
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#include <linux/jiffies.h>
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#include <linux/i2c.h>
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#include <linux/hwmon.h>
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#include <linux/hwmon-sysfs.h>
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#include <linux/err.h>
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#include <linux/mutex.h>
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#include <linux/i2c/max6639.h>
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/* Addresses to scan */
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static unsigned short normal_i2c[] = { 0x2c, 0x2e, 0x2f, I2C_CLIENT_END };
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/* The MAX6639 registers, valid channel numbers: 0, 1 */
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#define MAX6639_REG_TEMP(ch) (0x00 + (ch))
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#define MAX6639_REG_STATUS 0x02
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#define MAX6639_REG_OUTPUT_MASK 0x03
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#define MAX6639_REG_GCONFIG 0x04
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#define MAX6639_REG_TEMP_EXT(ch) (0x05 + (ch))
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#define MAX6639_REG_ALERT_LIMIT(ch) (0x08 + (ch))
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#define MAX6639_REG_OT_LIMIT(ch) (0x0A + (ch))
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#define MAX6639_REG_THERM_LIMIT(ch) (0x0C + (ch))
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#define MAX6639_REG_FAN_CONFIG1(ch) (0x10 + (ch) * 4)
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#define MAX6639_REG_FAN_CONFIG2a(ch) (0x11 + (ch) * 4)
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#define MAX6639_REG_FAN_CONFIG2b(ch) (0x12 + (ch) * 4)
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#define MAX6639_REG_FAN_CONFIG3(ch) (0x13 + (ch) * 4)
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#define MAX6639_REG_FAN_CNT(ch) (0x20 + (ch))
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#define MAX6639_REG_TARGET_CNT(ch) (0x22 + (ch))
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#define MAX6639_REG_FAN_PPR(ch) (0x24 + (ch))
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#define MAX6639_REG_TARGTDUTY(ch) (0x26 + (ch))
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#define MAX6639_REG_FAN_START_TEMP(ch) (0x28 + (ch))
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#define MAX6639_REG_DEVID 0x3D
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#define MAX6639_REG_MANUID 0x3E
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#define MAX6639_REG_DEVREV 0x3F
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#define MAX6639_GCONFIG_STANDBY 0x80
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#define MAX6639_GCONFIG_POR 0x40
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#define MAX6639_GCONFIG_DISABLE_TIMEOUT 0x20
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#define MAX6639_GCONFIG_CH2_LOCAL 0x10
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#define MAX6639_GCONFIG_PWM_FREQ_HI 0x08
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#define MAX6639_FAN_CONFIG1_PWM 0x80
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#define MAX6639_FAN_CONFIG3_THERM_FULL_SPEED 0x40
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static const int rpm_ranges[] = { 2000, 4000, 8000, 16000 };
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#define FAN_FROM_REG(val, div, rpm_range) ((val) == 0 ? -1 : \
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(val) == 255 ? 0 : (rpm_ranges[rpm_range] * 30) / ((div + 1) * (val)))
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#define TEMP_LIMIT_TO_REG(val) SENSORS_LIMIT((val) / 1000, 0, 255)
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* Client data (each client gets its own)
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struct device *hwmon_dev;
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struct mutex update_lock;
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char valid; /* !=0 if following fields are valid */
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unsigned long last_updated; /* In jiffies */
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/* Register values sampled regularly */
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u16 temp[2]; /* Temperature, in 1/8 C, 0..255 C */
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bool temp_fault[2]; /* Detected temperature diode failure */
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u8 fan[2]; /* Register value: TACH count for fans >=30 */
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u8 status; /* Detected channel alarms and fan failures */
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/* Register values only written to */
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u8 pwm[2]; /* Register value: Duty cycle 0..120 */
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u8 temp_therm[2]; /* THERM Temperature, 0..255 C (->_max) */
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u8 temp_alert[2]; /* ALERT Temperature, 0..255 C (->_crit) */
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u8 temp_ot[2]; /* OT Temperature, 0..255 C (->_emergency) */
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/* Register values initialized only once */
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u8 ppr; /* Pulses per rotation 0..3 for 1..4 ppr */
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u8 rpm_range; /* Index in above rpm_ranges table */
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static struct max6639_data *max6639_update_device(struct device *dev)
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struct i2c_client *client = to_i2c_client(dev);
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struct max6639_data *data = i2c_get_clientdata(client);
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struct max6639_data *ret = data;
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mutex_lock(&data->update_lock);
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if (time_after(jiffies, data->last_updated + 2 * HZ) || !data->valid) {
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dev_dbg(&client->dev, "Starting max6639 update\n");
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status_reg = i2c_smbus_read_byte_data(client,
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if (status_reg < 0) {
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ret = ERR_PTR(status_reg);
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data->status = status_reg;
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for (i = 0; i < 2; i++) {
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res = i2c_smbus_read_byte_data(client,
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MAX6639_REG_FAN_CNT(i));
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res = i2c_smbus_read_byte_data(client,
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MAX6639_REG_TEMP_EXT(i));
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data->temp[i] = res >> 5;
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data->temp_fault[i] = res & 0x01;
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res = i2c_smbus_read_byte_data(client,
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MAX6639_REG_TEMP(i));
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data->temp[i] |= res << 3;
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data->last_updated = jiffies;
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mutex_unlock(&data->update_lock);
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static ssize_t show_temp_input(struct device *dev,
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struct device_attribute *dev_attr, char *buf)
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struct max6639_data *data = max6639_update_device(dev);
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struct sensor_device_attribute *attr = to_sensor_dev_attr(dev_attr);
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return PTR_ERR(data);
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temp = data->temp[attr->index] * 125;
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return sprintf(buf, "%ld\n", temp);
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static ssize_t show_temp_fault(struct device *dev,
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struct device_attribute *dev_attr, char *buf)
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struct max6639_data *data = max6639_update_device(dev);
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struct sensor_device_attribute *attr = to_sensor_dev_attr(dev_attr);
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return PTR_ERR(data);
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return sprintf(buf, "%d\n", data->temp_fault[attr->index]);
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static ssize_t show_temp_max(struct device *dev,
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struct device_attribute *dev_attr, char *buf)
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struct i2c_client *client = to_i2c_client(dev);
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struct max6639_data *data = i2c_get_clientdata(client);
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struct sensor_device_attribute *attr = to_sensor_dev_attr(dev_attr);
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return sprintf(buf, "%d\n", (data->temp_therm[attr->index] * 1000));
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static ssize_t set_temp_max(struct device *dev,
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struct device_attribute *dev_attr,
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const char *buf, size_t count)
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struct i2c_client *client = to_i2c_client(dev);
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struct max6639_data *data = i2c_get_clientdata(client);
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struct sensor_device_attribute *attr = to_sensor_dev_attr(dev_attr);
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res = strict_strtoul(buf, 10, &val);
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mutex_lock(&data->update_lock);
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data->temp_therm[attr->index] = TEMP_LIMIT_TO_REG(val);
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i2c_smbus_write_byte_data(client,
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MAX6639_REG_THERM_LIMIT(attr->index),
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data->temp_therm[attr->index]);
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mutex_unlock(&data->update_lock);
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static ssize_t show_temp_crit(struct device *dev,
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struct device_attribute *dev_attr, char *buf)
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struct i2c_client *client = to_i2c_client(dev);
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struct max6639_data *data = i2c_get_clientdata(client);
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struct sensor_device_attribute *attr = to_sensor_dev_attr(dev_attr);
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return sprintf(buf, "%d\n", (data->temp_alert[attr->index] * 1000));
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static ssize_t set_temp_crit(struct device *dev,
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struct device_attribute *dev_attr,
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const char *buf, size_t count)
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struct i2c_client *client = to_i2c_client(dev);
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struct max6639_data *data = i2c_get_clientdata(client);
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struct sensor_device_attribute *attr = to_sensor_dev_attr(dev_attr);
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res = strict_strtoul(buf, 10, &val);
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mutex_lock(&data->update_lock);
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data->temp_alert[attr->index] = TEMP_LIMIT_TO_REG(val);
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i2c_smbus_write_byte_data(client,
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MAX6639_REG_ALERT_LIMIT(attr->index),
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data->temp_alert[attr->index]);
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mutex_unlock(&data->update_lock);
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static ssize_t show_temp_emergency(struct device *dev,
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struct device_attribute *dev_attr,
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struct i2c_client *client = to_i2c_client(dev);
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struct max6639_data *data = i2c_get_clientdata(client);
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struct sensor_device_attribute *attr = to_sensor_dev_attr(dev_attr);
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return sprintf(buf, "%d\n", (data->temp_ot[attr->index] * 1000));
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static ssize_t set_temp_emergency(struct device *dev,
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struct device_attribute *dev_attr,
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const char *buf, size_t count)
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struct i2c_client *client = to_i2c_client(dev);
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struct max6639_data *data = i2c_get_clientdata(client);
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struct sensor_device_attribute *attr = to_sensor_dev_attr(dev_attr);
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res = strict_strtoul(buf, 10, &val);
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mutex_lock(&data->update_lock);
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data->temp_ot[attr->index] = TEMP_LIMIT_TO_REG(val);
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i2c_smbus_write_byte_data(client,
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MAX6639_REG_OT_LIMIT(attr->index),
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data->temp_ot[attr->index]);
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mutex_unlock(&data->update_lock);
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static ssize_t show_pwm(struct device *dev,
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struct device_attribute *dev_attr, char *buf)
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struct i2c_client *client = to_i2c_client(dev);
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struct max6639_data *data = i2c_get_clientdata(client);
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struct sensor_device_attribute *attr = to_sensor_dev_attr(dev_attr);
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return sprintf(buf, "%d\n", data->pwm[attr->index] * 255 / 120);
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static ssize_t set_pwm(struct device *dev,
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struct device_attribute *dev_attr,
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const char *buf, size_t count)
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struct i2c_client *client = to_i2c_client(dev);
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struct max6639_data *data = i2c_get_clientdata(client);
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struct sensor_device_attribute *attr = to_sensor_dev_attr(dev_attr);
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res = strict_strtoul(buf, 10, &val);
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val = SENSORS_LIMIT(val, 0, 255);
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mutex_lock(&data->update_lock);
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data->pwm[attr->index] = (u8)(val * 120 / 255);
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i2c_smbus_write_byte_data(client,
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MAX6639_REG_TARGTDUTY(attr->index),
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data->pwm[attr->index]);
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mutex_unlock(&data->update_lock);
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static ssize_t show_fan_input(struct device *dev,
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struct device_attribute *dev_attr, char *buf)
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struct max6639_data *data = max6639_update_device(dev);
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struct sensor_device_attribute *attr = to_sensor_dev_attr(dev_attr);
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return PTR_ERR(data);
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return sprintf(buf, "%d\n", FAN_FROM_REG(data->fan[attr->index],
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data->ppr, data->rpm_range));
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static ssize_t show_alarm(struct device *dev,
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struct device_attribute *dev_attr, char *buf)
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struct max6639_data *data = max6639_update_device(dev);
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struct sensor_device_attribute *attr = to_sensor_dev_attr(dev_attr);
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return PTR_ERR(data);
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return sprintf(buf, "%d\n", !!(data->status & (1 << attr->index)));
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static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp_input, NULL, 0);
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static SENSOR_DEVICE_ATTR(temp2_input, S_IRUGO, show_temp_input, NULL, 1);
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static SENSOR_DEVICE_ATTR(temp1_fault, S_IRUGO, show_temp_fault, NULL, 0);
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static SENSOR_DEVICE_ATTR(temp2_fault, S_IRUGO, show_temp_fault, NULL, 1);
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static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, show_temp_max,
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static SENSOR_DEVICE_ATTR(temp2_max, S_IWUSR | S_IRUGO, show_temp_max,
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static SENSOR_DEVICE_ATTR(temp1_crit, S_IWUSR | S_IRUGO, show_temp_crit,
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static SENSOR_DEVICE_ATTR(temp2_crit, S_IWUSR | S_IRUGO, show_temp_crit,
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static SENSOR_DEVICE_ATTR(temp1_emergency, S_IWUSR | S_IRUGO,
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show_temp_emergency, set_temp_emergency, 0);
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static SENSOR_DEVICE_ATTR(temp2_emergency, S_IWUSR | S_IRUGO,
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show_temp_emergency, set_temp_emergency, 1);
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static SENSOR_DEVICE_ATTR(pwm1, S_IWUSR | S_IRUGO, show_pwm, set_pwm, 0);
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static SENSOR_DEVICE_ATTR(pwm2, S_IWUSR | S_IRUGO, show_pwm, set_pwm, 1);
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static SENSOR_DEVICE_ATTR(fan1_input, S_IRUGO, show_fan_input, NULL, 0);
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static SENSOR_DEVICE_ATTR(fan2_input, S_IRUGO, show_fan_input, NULL, 1);
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static SENSOR_DEVICE_ATTR(fan1_fault, S_IRUGO, show_alarm, NULL, 1);
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static SENSOR_DEVICE_ATTR(fan2_fault, S_IRUGO, show_alarm, NULL, 0);
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static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO, show_alarm, NULL, 3);
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static SENSOR_DEVICE_ATTR(temp2_max_alarm, S_IRUGO, show_alarm, NULL, 2);
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static SENSOR_DEVICE_ATTR(temp1_crit_alarm, S_IRUGO, show_alarm, NULL, 7);
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static SENSOR_DEVICE_ATTR(temp2_crit_alarm, S_IRUGO, show_alarm, NULL, 6);
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static SENSOR_DEVICE_ATTR(temp1_emergency_alarm, S_IRUGO, show_alarm, NULL, 5);
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static SENSOR_DEVICE_ATTR(temp2_emergency_alarm, S_IRUGO, show_alarm, NULL, 4);
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static struct attribute *max6639_attributes[] = {
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&sensor_dev_attr_temp1_input.dev_attr.attr,
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&sensor_dev_attr_temp2_input.dev_attr.attr,
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&sensor_dev_attr_temp1_fault.dev_attr.attr,
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&sensor_dev_attr_temp2_fault.dev_attr.attr,
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&sensor_dev_attr_temp1_max.dev_attr.attr,
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&sensor_dev_attr_temp2_max.dev_attr.attr,
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&sensor_dev_attr_temp1_crit.dev_attr.attr,
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&sensor_dev_attr_temp2_crit.dev_attr.attr,
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&sensor_dev_attr_temp1_emergency.dev_attr.attr,
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&sensor_dev_attr_temp2_emergency.dev_attr.attr,
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&sensor_dev_attr_pwm1.dev_attr.attr,
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&sensor_dev_attr_pwm2.dev_attr.attr,
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&sensor_dev_attr_fan1_input.dev_attr.attr,
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&sensor_dev_attr_fan2_input.dev_attr.attr,
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&sensor_dev_attr_fan1_fault.dev_attr.attr,
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&sensor_dev_attr_fan2_fault.dev_attr.attr,
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&sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
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&sensor_dev_attr_temp2_max_alarm.dev_attr.attr,
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&sensor_dev_attr_temp1_crit_alarm.dev_attr.attr,
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&sensor_dev_attr_temp2_crit_alarm.dev_attr.attr,
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&sensor_dev_attr_temp1_emergency_alarm.dev_attr.attr,
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&sensor_dev_attr_temp2_emergency_alarm.dev_attr.attr,
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static const struct attribute_group max6639_group = {
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.attrs = max6639_attributes,
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* returns respective index in rpm_ranges table
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* 1 by default on invalid range
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static int rpm_range_to_reg(int range)
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for (i = 0; i < ARRAY_SIZE(rpm_ranges); i++) {
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if (rpm_ranges[i] == range)
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return 1; /* default: 4000 RPM */
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static int max6639_init_client(struct i2c_client *client)
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struct max6639_data *data = i2c_get_clientdata(client);
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struct max6639_platform_data *max6639_info =
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client->dev.platform_data;
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int rpm_range = 1; /* default: 4000 RPM */
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/* Reset chip to default values, see below for GCONFIG setup */
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err = i2c_smbus_write_byte_data(client, MAX6639_REG_GCONFIG,
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MAX6639_GCONFIG_POR);
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/* Fans pulse per revolution is 2 by default */
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if (max6639_info && max6639_info->ppr > 0 &&
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max6639_info->ppr < 5)
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data->ppr = max6639_info->ppr;
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err = i2c_smbus_write_byte_data(client,
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MAX6639_REG_FAN_PPR(i),
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rpm_range = rpm_range_to_reg(max6639_info->rpm_range);
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data->rpm_range = rpm_range;
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for (i = 0; i < 2; i++) {
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/* Fans config PWM, RPM */
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err = i2c_smbus_write_byte_data(client,
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MAX6639_REG_FAN_CONFIG1(i),
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MAX6639_FAN_CONFIG1_PWM | rpm_range);
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/* Fans PWM polarity high by default */
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if (max6639_info && max6639_info->pwm_polarity == 0)
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err = i2c_smbus_write_byte_data(client,
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MAX6639_REG_FAN_CONFIG2a(i), 0x00);
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err = i2c_smbus_write_byte_data(client,
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MAX6639_REG_FAN_CONFIG2a(i), 0x02);
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* /THERM full speed enable,
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* PWM frequency 25kHz, see also GCONFIG below
482
err = i2c_smbus_write_byte_data(client,
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MAX6639_REG_FAN_CONFIG3(i),
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MAX6639_FAN_CONFIG3_THERM_FULL_SPEED | 0x03);
488
/* Max. temp. 80C/90C/100C */
489
data->temp_therm[i] = 80;
490
data->temp_alert[i] = 90;
491
data->temp_ot[i] = 100;
492
err = i2c_smbus_write_byte_data(client,
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MAX6639_REG_THERM_LIMIT(i),
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data->temp_therm[i]);
497
err = i2c_smbus_write_byte_data(client,
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MAX6639_REG_ALERT_LIMIT(i),
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data->temp_alert[i]);
502
err = i2c_smbus_write_byte_data(client,
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MAX6639_REG_OT_LIMIT(i), data->temp_ot[i]);
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/* PWM 120/120 (i.e. 100%) */
509
err = i2c_smbus_write_byte_data(client,
510
MAX6639_REG_TARGTDUTY(i), data->pwm[i]);
514
/* Start monitoring */
515
err = i2c_smbus_write_byte_data(client, MAX6639_REG_GCONFIG,
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MAX6639_GCONFIG_DISABLE_TIMEOUT | MAX6639_GCONFIG_CH2_LOCAL |
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MAX6639_GCONFIG_PWM_FREQ_HI);
522
/* Return 0 if detection is successful, -ENODEV otherwise */
523
static int max6639_detect(struct i2c_client *client,
524
struct i2c_board_info *info)
526
struct i2c_adapter *adapter = client->adapter;
529
if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
532
/* Actual detection via device and manufacturer ID */
533
dev_id = i2c_smbus_read_byte_data(client, MAX6639_REG_DEVID);
534
manu_id = i2c_smbus_read_byte_data(client, MAX6639_REG_MANUID);
535
if (dev_id != 0x58 || manu_id != 0x4D)
538
strlcpy(info->type, "max6639", I2C_NAME_SIZE);
543
static int max6639_probe(struct i2c_client *client,
544
const struct i2c_device_id *id)
546
struct max6639_data *data;
549
data = kzalloc(sizeof(struct max6639_data), GFP_KERNEL);
555
i2c_set_clientdata(client, data);
556
mutex_init(&data->update_lock);
558
/* Initialize the max6639 chip */
559
err = max6639_init_client(client);
563
/* Register sysfs hooks */
564
err = sysfs_create_group(&client->dev.kobj, &max6639_group);
568
data->hwmon_dev = hwmon_device_register(&client->dev);
569
if (IS_ERR(data->hwmon_dev)) {
570
err = PTR_ERR(data->hwmon_dev);
574
dev_info(&client->dev, "temperature sensor and fan control found\n");
579
sysfs_remove_group(&client->dev.kobj, &max6639_group);
586
static int max6639_remove(struct i2c_client *client)
588
struct max6639_data *data = i2c_get_clientdata(client);
590
hwmon_device_unregister(data->hwmon_dev);
591
sysfs_remove_group(&client->dev.kobj, &max6639_group);
597
static int max6639_suspend(struct i2c_client *client, pm_message_t mesg)
599
int data = i2c_smbus_read_byte_data(client, MAX6639_REG_GCONFIG);
603
return i2c_smbus_write_byte_data(client,
604
MAX6639_REG_GCONFIG, data | MAX6639_GCONFIG_STANDBY);
607
static int max6639_resume(struct i2c_client *client)
609
int data = i2c_smbus_read_byte_data(client, MAX6639_REG_GCONFIG);
613
return i2c_smbus_write_byte_data(client,
614
MAX6639_REG_GCONFIG, data & ~MAX6639_GCONFIG_STANDBY);
617
static const struct i2c_device_id max6639_id[] = {
622
MODULE_DEVICE_TABLE(i2c, max6639_id);
624
static struct i2c_driver max6639_driver = {
625
.class = I2C_CLASS_HWMON,
629
.probe = max6639_probe,
630
.remove = max6639_remove,
631
.suspend = max6639_suspend,
632
.resume = max6639_resume,
633
.id_table = max6639_id,
634
.detect = max6639_detect,
635
.address_list = normal_i2c,
638
static int __init max6639_init(void)
640
return i2c_add_driver(&max6639_driver);
643
static void __exit max6639_exit(void)
645
i2c_del_driver(&max6639_driver);
648
MODULE_AUTHOR("Roland Stigge <stigge@antcom.de>");
649
MODULE_DESCRIPTION("max6639 driver");
650
MODULE_LICENSE("GPL");
652
module_init(max6639_init);
653
module_exit(max6639_exit);