/*
* max6650.c - Part of lm_sensors, Linux kernel modules for hardware
* monitoring.
*
* (C) 2007 by Hans J. Koch <hjk@linutronix.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.
*
* Tha 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 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);
I2C_CLIENT_INSMOD_1(max6650);
/*
* 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
/* 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_attach_adapter(struct i2c_adapter *adapter);
static int max6650_detect(struct i2c_adapter *adapter, int address, int kind);
static int max6650_init_client(struct i2c_client *client);
static int max6650_detach_client(struct i2c_client *client);
static struct max6650_data *max6650_update_device(struct device *dev);
/*
* Driver data (common to all clients)
*/
static struct i2c_driver max6650_driver = {
.driver = {
.name = "max6650",
},
.attach_adapter = max6650_attach_adapter,
.detach_client = max6650_detach_client,
};
/*
* Client data (each client gets its own)
*/
struct max6650_data
{
struct i2c_client client;
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;
};
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 device_attribute *devattr,
char *buf)
{
int pwm;
struct max6650_data *data = max6650_update_device(dev);
/* Useful range for dac is 0-180 for 12V fans and 0-76 for 5V fans.
Lower DAC values mean higher speeds. */
if (data->config & MAX6650_CFG_V12)
pwm = 255 - (255 * (int)data->dac)/180;
else
pwm = 255 - (255 * (int)data->dac)/76;
if (pwm < 0)
pwm = 0;
return sprintf(buf, "%d\n", pwm);
}
static ssize_t set_pwm(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 pwm = simple_strtoul(buf, NULL, 10);
pwm = SENSORS_LIMIT(pwm, 0, 255);
mutex_lock(&data->update_lock);
if (data->config & MAX6650_CFG_V12)
data->dac = 180 - (180 * pwm)/255;
else
data->dac = 76 - (76 * pwm)/255;
i2c_smbus_write_byte_data(client, MAX6650_REG_DAC, data->dac);
mutex_unlock(&data->update_lock);
return count;
}
/*
* Get/Set controller mode:
* Possible values:
* 0 = Fan always on
* 1 = Open loop, Voltage is set according to speed, not regulated.
* 2 = Closed loop, RPM for all fans regulated by fan1 tachometer
*/
static ssize_t get_enable(struct device *dev, struct device_attribute *devattr,
char *buf)
{
struct max6650_data *data = max6650_update_device(dev);
int mode = (data->config & MAX6650_CFG_MODE_MASK) >> 4;
int sysfs_modes[4] = {0, 1, 2, 1};
return sprintf(buf, "%d\n", sysfs_modes[mode]);
}
static ssize_t set_enable(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 mode = simple_strtoul(buf, NULL, 10);
int max6650_modes[3] = {0, 3, 2};
if ((mode < 0)||(mode > 2)) {
dev_err(&client->dev,
"illegal value for pwm1_enable (%d)\n", mode);
return -EINVAL;
}
mutex_lock(&data->update_lock);
data->config = i2c_smbus_read_byte_data(client, MAX6650_REG_CONFIG);
data->config = (data->config & ~MAX6650_CFG_MODE_MASK)
| (max6650_modes[mode] << 4);
i2c_smbus_write_byte_data(client, MAX6650_REG_CONFIG, data->config);
mutex_unlock(&data->update_lock);
return count;
}
/*
* Read/write functions for fan1_div sysfs file. The MAX6650 has no such
* divider. We handle this by converting between divider and counttime:
*
* (counttime == k) <==> (divider == 2^k), k = 0, 1, 2, or 3
*
* Lower values of k allow to connect a faster fan without the risk of
* counter overflow. The price is lower resolution. You can also set counttime
* using the module parameter. Note that the module parameter "prescaler" also
* influences the behaviour. Unfortunately, there's no sysfs attribute
* defined for that. See the data sheet for details.
*/
static ssize_t get_div(struct device *dev, struct device_attribute *devattr,
char *buf)
{
struct max6650_data *data = max6650_update_device(dev);
return sprintf(buf, "%d\n", DIV_FROM_REG(data->count));
}
static ssize_t set_div(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 div = simple_strtoul(buf, NULL, 10);
mutex_lock(&data->update_lock);
switch (div) {
case 1:
data->count = 0;
break;
case 2:
data->count = 1;
break;
case 4:
data->count = 2;
break;
case 8:
data->count = 3;
break;
default:
dev_err(&client->dev,
"illegal value for fan divider (%d)\n", div);
return -EINVAL;
}
i2c_smbus_write_byte_data(client, MAX6650_REG_COUNT, data->count);
mutex_unlock(&data->update_lock);
return count;
}
static SENSOR_DEVICE_ATTR(fan1_input, S_IRUGO, get_fan, NULL, 0);
static SENSOR_DEVICE_ATTR(fan2_input, S_IRUGO, get_fan, NULL, 1);
static SENSOR_DEVICE_ATTR(fan3_input, S_IRUGO, get_fan, NULL, 2);
static SENSOR_DEVICE_ATTR(fan4_input, S_IRUGO, get_fan, NULL, 3);
static DEVICE_ATTR(fan1_target, S_IWUSR | S_IRUGO, get_target, set_target);
static DEVICE_ATTR(fan1_div, S_IWUSR | S_IRUGO, get_div, set_div);
static DEVICE_ATTR(pwm1_enable, S_IWUSR | S_IRUGO, get_enable, set_enable);
static DEVICE_ATTR(pwm1, S_IWUSR | S_IRUGO, get_pwm, set_pwm);
static struct attribute *max6650_attrs[] = {
&sensor_dev_attr_fan1_input.dev_attr.attr,
&sensor_dev_attr_fan2_input.dev_attr.attr,
&sensor_dev_attr_fan3_input.dev_attr.attr,
&sensor_dev_attr_fan4_input.dev_attr.attr,
&dev_attr_fan1_target.attr,
&dev_attr_fan1_div.attr,
&dev_attr_pwm1_enable.attr,
&dev_attr_pwm1.attr,
NULL
};
static struct attribute_group max6650_attr_grp = {
.attrs = max6650_attrs,
};
/*
* Real code
*/
static int max6650_attach_adapter(struct i2c_adapter *adapter)
{
if (!(adapter->class & I2C_CLASS_HWMON)) {
dev_dbg(&adapter->dev,
"FATAL: max6650_attach_adapter class HWMON not set\n");
return 0;
}
return i2c_probe(adapter, &addr_data, max6650_detect);
}
/*
* The following function does more than just detection. If detection
* succeeds, it also registers the new chip.
*/
static int max6650_detect(struct i2c_adapter *adapter, int address, int kind)
{
struct i2c_client *client;
struct max6650_data *data;
int err = -ENODEV;
dev_dbg(&adapter->dev, "max6650_detect called, kind = %d\n", kind);
if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA)) {
dev_dbg(&adapter->dev, "max6650: I2C bus doesn't support "
"byte read mode, skipping.\n");
return 0;
}
if (!(data = kzalloc(sizeof(struct max6650_data), GFP_KERNEL))) {
dev_err(&adapter->dev, "max6650: out of memory.\n");
return -ENOMEM;
}
client = &data->client;
i2c_set_clientdata(client, data);
client->addr = address;
client->adapter = adapter;
client->driver = &max6650_driver;
/*
* Now we do the remaining detection. A negative kind means that
* the driver was loaded with no force parameter (default), so we
* must both detect and identify the chip (actually there is only
* one possible kind of chip for now, max6650). A zero kind means that
* the driver was loaded with the force parameter, the detection
* step shall be skipped. A positive kind means that the driver
* was loaded with the force parameter and a given kind of chip is
* requested, so both the detection and the identification steps
* are skipped.
*
* Currently I can find no way to distinguish between a MAX6650 and
* a MAX6651. This driver has only been tried on the former.
*/
if ((kind < 0) &&
( (i2c_smbus_read_byte_data(client, MAX6650_REG_CONFIG) & 0xC0)
||(i2c_smbus_read_byte_data(client, MAX6650_REG_GPIO_STAT) & 0xE0)
||(i2c_smbus_read_byte_data(client, MAX6650_REG_ALARM_EN) & 0xE0)
||(i2c_smbus_read_byte_data(client, MAX6650_REG_ALARM) & 0xE0)
||(i2c_smbus_read_byte_data(client, MAX6650_REG_COUNT) & 0xFC))) {
dev_dbg(&adapter->dev,
"max6650: detection failed at 0x%02x.\n", address);
goto err_free;
}
dev_info(&adapter->dev, "max6650: chip found at 0x%02x.\n", address);
strlcpy(client->name, "max6650", I2C_NAME_SIZE);
mutex_init(&data->update_lock);
if ((err = i2c_attach_client(client))) {
dev_err(&adapter->dev, "max6650: failed to attach client.\n");
goto err_free;
}
/*
* Initialize the max6650 chip
*/
if (max6650_init_client(client))
goto err_detach;
err = sysfs_create_group(&client->dev.kobj, &max6650_attr_grp);
if (err)
goto err_detach;
data->hwmon_dev = hwmon_device_register(&client->dev);
if (!IS_ERR(data->hwmon_dev))
return 0;
err = PTR_ERR(data->hwmon_dev);
dev_err(&client->dev, "error registering hwmon device.\n");
sysfs_remove_group(&client->dev.kobj, &max6650_attr_grp);
err_detach:
i2c_detach_client(client);
err_free:
kfree(data);
return err;
}
static int max6650_detach_client(struct i2c_client *client)
{
struct max6650_data *data = i2c_get_clientdata(client);
int err;
sysfs_remove_group(&client->dev.kobj, &max6650_attr_grp);
hwmon_device_unregister(data->hwmon_dev);
err = i2c_detach_client(client);
if (!err)
kfree(data);
return err;
}
static int max6650_init_client(struct i2c_client *client)
{
struct max6650_data *data = i2c_get_clientdata(client);
int config;
int err = -EIO;
config = i2c_smbus_read_byte_data(client, MAX6650_REG_CONFIG);
if (config < 0) {
dev_err(&client->dev, "Error reading config, aborting.\n");
return err;
}
switch (fan_voltage) {
case 0:
break;
case 5:
config &= ~MAX6650_CFG_V12;
break;
case 12:
config |= MAX6650_CFG_V12;
break;
default:
dev_err(&client->dev,
"illegal value for fan_voltage (%d)\n",
fan_voltage);
}
dev_info(&client->dev, "Fan voltage is set to %dV.\n",
(config & MAX6650_CFG_V12) ? 12 : 5);
switch (prescaler) {
case 0:
break;
case 1:
config &= ~MAX6650_CFG_PRESCALER_MASK;
break;
case 2:
config = (config & ~MAX6650_CFG_PRESCALER_MASK)
| MAX6650_CFG_PRESCALER_2;
break;
case 4:
config = (config & ~MAX6650_CFG_PRESCALER_MASK)
| MAX6650_CFG_PRESCALER_4;
break;
case 8:
config = (config & ~MAX6650_CFG_PRESCALER_MASK)
| MAX6650_CFG_PRESCALER_8;
break;
case 16:
config = (config & ~MAX6650_CFG_PRESCALER_MASK)
| MAX6650_CFG_PRESCALER_16;
break;
default:
dev_err(&client->dev,
"illegal value for prescaler (%d)\n",
prescaler);
}
dev_info(&client->dev, "Prescaler is set to %d.\n",
1 << (config & MAX6650_CFG_PRESCALER_MASK));
/* If mode is set to "full off", we change it to "open loop" and
* set DAC to 255, which has the same effect. We do this because
* there's no "full off" mode defined in hwmon specifcations.
*/
if ((config & MAX6650_CFG_MODE_MASK) == MAX6650_CFG_MODE_OFF) {
dev_dbg(&client->dev, "Change mode to open loop, full off.\n");
config = (config & ~MAX6650_CFG_MODE_MASK)
| MAX6650_CFG_MODE_OPEN_LOOP;
if (i2c_smbus_write_byte_data(client, MAX6650_REG_DAC, 255)) {
dev_err(&client->dev, "DAC write error, aborting.\n");
return err;
}
}
if (i2c_smbus_write_byte_data(client, MAX6650_REG_CONFIG, config)) {
dev_err(&client->dev, "Config write error, aborting.\n");
return err;
}
data->config = config;
data->count = i2c_smbus_read_byte_data(client, MAX6650_REG_COUNT);
return 0;
}
static const u8 tach_reg[] = {
MAX6650_REG_TACH0,
MAX6650_REG_TACH1,
MAX6650_REG_TACH2,
MAX6650_REG_TACH3,
};
static struct max6650_data *max6650_update_device(struct device *dev)
{
int i;
struct i2c_client *client = to_i2c_client(dev);
struct max6650_data *data = i2c_get_clientdata(client);
mutex_lock(&data->update_lock);
if (time_after(jiffies, data->last_updated + HZ) || !data->valid) {
data->speed = i2c_smbus_read_byte_data(client,
MAX6650_REG_SPEED);
data->config = i2c_smbus_read_byte_data(client,
MAX6650_REG_CONFIG);
for (i = 0; i < 4; i++) {
data->tach[i] = i2c_smbus_read_byte_data(client,
tach_reg[i]);
}
data->count = i2c_smbus_read_byte_data(client,
MAX6650_REG_COUNT);
data->dac = i2c_smbus_read_byte_data(client, MAX6650_REG_DAC);
data->last_updated = jiffies;
data->valid = 1;
}
mutex_unlock(&data->update_lock);
return data;
}
static int __init sensors_max6650_init(void)
{
return i2c_add_driver(&max6650_driver);
}
static void __exit sensors_max6650_exit(void)
{
i2c_del_driver(&max6650_driver);
}
MODULE_AUTHOR("Hans J. Koch");
MODULE_DESCRIPTION("MAX6650 sensor driver");
MODULE_LICENSE("GPL");
module_init(sensors_max6650_init);
module_exit(sensors_max6650_exit);
