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|
/*
* max6650.c - Part of lm_sensors, Linux kernel modules for hardware
* monitoring.
*
* (C) 2007 by Hans J. Koch <hjk@hansjkoch.de>
*
* based on code written by John Morris <john.morris@spirentcom.com>
* Copyright (c) 2003 Spirent Communications
* and Claus Gindhart <claus.gindhart@kontron.com>
*
* This module has only been tested with the MAX6650 chip. It should
* also work with the MAX6651. It does not distinguish max6650 and max6651
* chips.
*
* The datasheet was last seen at:
*
* http://pdfserv.maxim-ic.com/en/ds/MAX6650-MAX6651.pdf
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <linux/module.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/jiffies.h>
#include <linux/i2c.h>
#include <linux/hwmon.h>
#include <linux/hwmon-sysfs.h>
#include <linux/err.h>
/*
* Addresses to scan. There are four disjoint possibilities, by pin config.
*/
static const unsigned short normal_i2c[] = {0x1b, 0x1f, 0x48, 0x4b,
I2C_CLIENT_END};
/*
* Insmod parameters
*/
/* fan_voltage: 5=5V fan, 12=12V fan, 0=don't change */
static int fan_voltage;
/* prescaler: Possible values are 1, 2, 4, 8, 16 or 0 for don't change */
static int prescaler;
/* clock: The clock frequency of the chip the driver should assume */
static int clock = 254000;
module_param(fan_voltage, int, S_IRUGO);
module_param(prescaler, int, S_IRUGO);
module_param(clock, int, S_IRUGO);
/*
* MAX 6650/6651 registers
*/
#define MAX6650_REG_SPEED 0x00
#define MAX6650_REG_CONFIG 0x02
#define MAX6650_REG_GPIO_DEF 0x04
#define MAX6650_REG_DAC 0x06
#define MAX6650_REG_ALARM_EN 0x08
#define MAX6650_REG_ALARM 0x0A
#define MAX6650_REG_TACH0 0x0C
#define MAX6650_REG_TACH1 0x0E
#define MAX6650_REG_TACH2 0x10
#define MAX6650_REG_TACH3 0x12
#define MAX6650_REG_GPIO_STAT 0x14
#define MAX6650_REG_COUNT 0x16
/*
* Config register bits
*/
#define MAX6650_CFG_V12 0x08
#define MAX6650_CFG_PRESCALER_MASK 0x07
#define MAX6650_CFG_PRESCALER_2 0x01
#define MAX6650_CFG_PRESCALER_4 0x02
#define MAX6650_CFG_PRESCALER_8 0x03
#define MAX6650_CFG_PRESCALER_16 0x04
#define MAX6650_CFG_MODE_MASK 0x30
#define MAX6650_CFG_MODE_ON 0x00
#define MAX6650_CFG_MODE_OFF 0x10
#define MAX6650_CFG_MODE_CLOSED_LOOP 0x20
#define MAX6650_CFG_MODE_OPEN_LOOP 0x30
#define MAX6650_COUNT_MASK 0x03
/*
* Alarm status register bits
*/
#define MAX6650_ALRM_MAX 0x01
#define MAX6650_ALRM_MIN 0x02
#define MAX6650_ALRM_TACH 0x04
#define MAX6650_ALRM_GPIO1 0x08
#define MAX6650_ALRM_GPIO2 0x10
/* Minimum and maximum values of the FAN-RPM */
#define FAN_RPM_MIN 240
#define FAN_RPM_MAX 30000
#define DIV_FROM_REG(reg) (1 << (reg & 7))
static int max6650_probe(struct i2c_client *client,
const struct i2c_device_id *id);
static int max6650_detect(struct i2c_client *client,
struct i2c_board_info *info);
static int max6650_init_client(struct i2c_client *client);
static int max6650_remove(struct i2c_client *client);
static struct max6650_data *max6650_update_device(struct device *dev);
/*
* Driver data (common to all clients)
*/
static const struct i2c_device_id max6650_id[] = {
{ "max6650", 0 },
{ }
};
MODULE_DEVICE_TABLE(i2c, max6650_id);
static struct i2c_driver max6650_driver = {
.class = I2C_CLASS_HWMON,
.driver = {
.name = "max6650",
},
.probe = max6650_probe,
.remove = max6650_remove,
.id_table = max6650_id,
.detect = max6650_detect,
.address_list = normal_i2c,
};
/*
* Client data (each client gets its own)
*/
struct max6650_data
{
struct device *hwmon_dev;
struct mutex update_lock;
char valid; /* zero until following fields are valid */
unsigned long last_updated; /* in jiffies */
/* register values */
u8 speed;
u8 config;
u8 tach[4];
u8 count;
u8 dac;
u8 alarm;
};
static ssize_t get_fan(struct device *dev, struct device_attribute *devattr,
char *buf)
{
struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
struct max6650_data *data = max6650_update_device(dev);
int rpm;
/*
* Calculation details:
*
* Each tachometer counts over an interval given by the "count"
* register (0.25, 0.5, 1 or 2 seconds). This module assumes
* that the fans produce two pulses per revolution (this seems
* to be the most common).
*/
rpm = ((data->tach[attr->index] * 120) / DIV_FROM_REG(data->count));
return sprintf(buf, "%d\n", rpm);
}
/*
* Set the fan speed to the specified RPM (or read back the RPM setting).
* This works in closed loop mode only. Use pwm1 for open loop speed setting.
*
* The MAX6650/1 will automatically control fan speed when in closed loop
* mode.
*
* Assumptions:
*
* 1) The MAX6650/1 internal 254kHz clock frequency is set correctly. Use
* the clock module parameter if you need to fine tune this.
*
* 2) The prescaler (low three bits of the config register) has already
* been set to an appropriate value. Use the prescaler module parameter
* if your BIOS doesn't initialize the chip properly.
*
* The relevant equations are given on pages 21 and 22 of the datasheet.
*
* From the datasheet, the relevant equation when in regulation is:
*
* [fCLK / (128 x (KTACH + 1))] = 2 x FanSpeed / KSCALE
*
* where:
*
* fCLK is the oscillator frequency (either the 254kHz internal
* oscillator or the externally applied clock)
*
* KTACH is the value in the speed register
*
* FanSpeed is the speed of the fan in rps
*
* KSCALE is the prescaler value (1, 2, 4, 8, or 16)
*
* When reading, we need to solve for FanSpeed. When writing, we need to
* solve for KTACH.
*
* Note: this tachometer is completely separate from the tachometers
* used to measure the fan speeds. Only one fan's speed (fan1) is
* controlled.
*/
static ssize_t get_target(struct device *dev, struct device_attribute *devattr,
char *buf)
{
struct max6650_data *data = max6650_update_device(dev);
int kscale, ktach, rpm;
/*
* Use the datasheet equation:
*
* FanSpeed = KSCALE x fCLK / [256 x (KTACH + 1)]
*
* then multiply by 60 to give rpm.
*/
kscale = DIV_FROM_REG(data->config);
ktach = data->speed;
rpm = 60 * kscale * clock / (256 * (ktach + 1));
return sprintf(buf, "%d\n", rpm);
}
static ssize_t set_target(struct device *dev, struct device_attribute *devattr,
const char *buf, size_t count)
{
struct i2c_client *client = to_i2c_client(dev);
struct max6650_data *data = i2c_get_clientdata(client);
int rpm = simple_strtoul(buf, NULL, 10);
int kscale, ktach;
rpm = SENSORS_LIMIT(rpm, FAN_RPM_MIN, FAN_RPM_MAX);
/*
* Divide the required speed by 60 to get from rpm to rps, then
* use the datasheet equation:
*
* KTACH = [(fCLK x KSCALE) / (256 x FanSpeed)] - 1
*/
mutex_lock(&data->update_lock);
kscale = DIV_FROM_REG(data->config);
ktach = ((clock * kscale) / (256 * rpm / 60)) - 1;
if (ktach < 0)
ktach = 0;
if (ktach > 255)
ktach = 255;
data->speed = ktach;
i2c_smbus_write_byte_data(client, MAX6650_REG_SPEED, data->speed);
mutex_unlock(&data->update_lock);
return count;
}
/*
* Get/set the fan speed in open loop mode using pwm1 sysfs file.
* Speed is given as a relative value from 0 to 255, where 255 is maximum
* speed. Note that this is done by writing directly to the chip's DAC,
* it won't change the closed loop speed set by fan1_target.
* Also note that due to rounding errors it is possible that you don't read
* back exactly the value you have set.
*/
static ssize_t get_pwm(struct device *dev, struct
|