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linux/drivers/hwmon/max6650.c

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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>
#include <linux/of_device.h>
/*
* 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 (max6651 can be clocked externally) */
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))
/*
* Client data (each client gets its own)
*/
struct max6650_data {
struct i2c_client *client;
const struct attribute_group *groups[3];
struct mutex update_lock;
int nr_fans;
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 const u8 tach_reg[] = {
MAX6650_REG_TACH0,
MAX6650_REG_TACH1,
MAX6650_REG_TACH2,
MAX6650_REG_TACH3,
};
static const struct of_device_id max6650_dt_match[] = {
{
.compatible = "maxim,max6650",
.data = (void *)1
},
{
.compatible = "maxim,max6651",
.data = (void *)4
},
{ },
};
MODULE_DEVICE_TABLE(of, max6650_dt_match);
static struct max6650_data *max6650_update_device(struct device *dev)
{
struct max6650_data *data = dev_get_drvdata(dev);
struct i2c_client *client = data->client;
int i;
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 < data->nr_fans; 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);
/*
* Alarms are cleared on read in case the condition that
* caused the alarm is removed. Keep the value latched here
* for providing the register through different alarm files.
*/
data->alarm |= i2c_smbus_read_byte_data(client,
MAX6650_REG_ALARM);
data->last_updated = jiffies;
data->valid = 1;
}
mutex_unlock(&data->update_lock);
return data;
}
/*
* Change the operating mode of the chip (if needed).
* mode is one of the MAX6650_CFG_MODE_* values.
*/
static int max6650_set_operating_mode(struct max6650_data *data, u8 mode)
{
int result;
u8 config = data->config;
if (mode == (config & MAX6650_CFG_MODE_MASK))
return 0;
config = (config & ~MAX6650_CFG_MODE_MASK) | mode;
result = i2c_smbus_write_byte_data(data->client, MAX6650_REG_CONFIG,
config);
if (result < 0)
return result;
data->config = config;
return 0;
}
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 fan1_target_show(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 int max6650_set_target(struct max6650_data *data, unsigned long rpm)
{
int kscale, ktach;
if (rpm == 0)
return max6650_set_operating_mode(data, MAX6650_CFG_MODE_OFF);
rpm = clamp_val(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
*/
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;
return i2c_smbus_write_byte_data(data->client, MAX6650_REG_SPEED,
data->speed);
}
static ssize_t fan1_target_store(struct device *dev,
struct device_attribute *devattr,
const char *buf, size_t count)
{
struct max6650_data *data = dev_get_drvdata(dev);
unsigned long rpm;
int err;
err = kstrtoul(buf, 10, &rpm);
if (err)
return err;
mutex_lock(&data->update_lock);
err = max6650_set_target(data, rpm);
mutex_unlock(&data->update_lock);
if (err < 0)
return err;
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 pwm1_show(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 pwm1_store(struct device *dev,
struct device_attribute *devattr, const char *buf,
size_t count)
{
struct max6650_data *data = dev_get_drvdata(dev);
struct i2c_client *client = data->client;
unsigned long pwm;
int err;
err = kstrtoul(buf, 10, &pwm);
if (err)
return err;
pwm = clamp_val(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;
err = i2c_smbus_write_byte_data(client, MAX6650_REG_DAC, data->dac);
mutex_unlock(&data->update_lock);
return err < 0 ? err : 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
* 3 = Fan off
*/
static ssize_t pwm1_enable_show(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, 3, 2, 1};
return sprintf(buf, "%d\n", sysfs_modes[mode]);
}
static ssize_t pwm1_enable_store(struct device *dev,
struct device_attribute *devattr,
const char *buf, size_t count)
{
struct max6650_data *data = dev_get_drvdata(dev);
unsigned long mode;
int err;
const u8 max6650_modes[] = {
MAX6650_CFG_MODE_ON,
MAX6650_CFG_MODE_OPEN_LOOP,
MAX6650_CFG_MODE_CLOSED_LOOP,
MAX6650_CFG_MODE_OFF,
};
err = kstrtoul(buf, 10, &mode);
if (err)
return err;
if (mode >= ARRAY_SIZE(max6650_modes))
return -EINVAL;
mutex_lock(&data->update_lock);
max6650_set_operating_mode(data, max6650_modes[mode]);
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 fan1_div_show(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 fan1_div_store(struct device *dev,
struct device_attribute *devattr,
const char *buf, size_t count)
{
struct max6650_data *data = dev_get_drvdata(dev);
struct i2c_client *client = data->client;
unsigned long div;
int err;
err = kstrtoul(buf, 10, &div);
if (err)
return err;
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:
mutex_unlock(&data->update_lock);
return -EINVAL;
}
i2c_smbus_write_byte_data(client, MAX6650_REG_COUNT, data->count);
mutex_unlock(&data->update_lock);
return count;
}
/*
* Get alarm stati:
* Possible values:
* 0 = no alarm
* 1 = alarm
*/
static ssize_t get_alarm(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);
struct i2c_client *client = data->client;
int alarm = 0;
if (data->alarm & attr->index) {
mutex_lock(&data->update_lock);
alarm = 1;
data->alarm &= ~attr->index;
data->alarm |= i2c_smbus_read_byte_data(client,
MAX6650_REG_ALARM);
mutex_unlock(&data->update_lock);
}
return sprintf(buf, "%d\n", alarm);
}
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_RW(fan1_target);
static DEVICE_ATTR_RW(fan1_div);
static DEVICE_ATTR_RW(pwm1_enable);
static DEVICE_ATTR_RW(pwm1);
static SENSOR_DEVICE_ATTR(fan1_max_alarm, S_IRUGO, get_alarm, NULL,
MAX6650_ALRM_MAX);
static SENSOR_DEVICE_ATTR(fan1_min_alarm, S_IRUGO, get_alarm, NULL,
MAX6650_ALRM_MIN);
static SENSOR_DEVICE_ATTR(fan1_fault, S_IRUGO, get_alarm, NULL,
MAX6650_ALRM_TACH);
static SENSOR_DEVICE_ATTR(gpio1_alarm, S_IRUGO, get_alarm, NULL,
MAX6650_ALRM_GPIO1);
static SENSOR_DEVICE_ATTR(gpio2_alarm, S_IRUGO, get_alarm, NULL,
MAX6650_ALRM_GPIO2);
static umode_t max6650_attrs_visible(struct kobject *kobj, struct attribute *a,
int n)
{
struct device *dev = container_of(kobj, struct device, kobj);
struct max6650_data *data = dev_get_drvdata(dev);
struct i2c_client *client = data->client;
u8 alarm_en = i2c_smbus_read_byte_data(client, MAX6650_REG_ALARM_EN);
struct device_attribute *devattr;
/*
* Hide the alarms that have not been enabled by the firmware
*/
devattr = container_of(a, struct device_attribute, attr);
if (devattr == &sensor_dev_attr_fan1_max_alarm.dev_attr
|| devattr == &sensor_dev_attr_fan1_min_alarm.dev_attr
|| devattr == &sensor_dev_attr_fan1_fault.dev_attr
|| devattr == &sensor_dev_attr_gpio1_alarm.dev_attr
|| devattr == &sensor_dev_attr_gpio2_alarm.dev_attr) {
if (!(alarm_en & to_sensor_dev_attr(devattr)->index))
return 0;
}
return a->mode;
}
static struct attribute *max6650_attrs[] = {
&sensor_dev_attr_fan1_input.dev_attr.attr,
&dev_attr_fan1_target.attr,
&dev_attr_fan1_div.attr,
&dev_attr_pwm1_enable.attr,
&dev_attr_pwm1.attr,
&sensor_dev_attr_fan1_max_alarm.dev_attr.attr,
&sensor_dev_attr_fan1_min_alarm.dev_attr.attr,
&sensor_dev_attr_fan1_fault.dev_attr.attr,
&sensor_dev_attr_gpio1_alarm.dev_attr.attr,
&sensor_dev_attr_gpio2_alarm.dev_attr.attr,
NULL
};
static const struct attribute_group max6650_group = {
.attrs = max6650_attrs,
.is_visible = max6650_attrs_visible,
};
static struct attribute *max6651_attrs[] = {
&sensor_dev_attr_fan2_input.dev_attr.attr,
&sensor_dev_attr_fan3_input.dev_attr.attr,
&sensor_dev_attr_fan4_input.dev_attr.attr,
NULL
};
static const struct attribute_group max6651_group = {
.attrs = max6651_attrs,
};
/*
* Real code
*/
static int max6650_init_client(struct max6650_data *data,
struct i2c_client *client)
{
struct device *dev = &client->dev;
int config;
int err = -EIO;
u32 voltage;
u32 prescale;
u32 target_rpm;
if (of_property_read_u32(dev->of_node, "maxim,fan-microvolt",
&voltage))
voltage = fan_voltage;
else
voltage /= 1000000; /* Microvolts to volts */
if (of_property_read_u32(dev->of_node, "maxim,fan-prescale",
&prescale))
prescale = prescaler;
config = i2c_smbus_read_byte_data(client, MAX6650_REG_CONFIG);
if (config < 0) {
dev_err(dev, "Error reading config, aborting.\n");
return err;
}
switch (voltage) {
case 0:
break;
case 5:
config &= ~MAX6650_CFG_V12;
break;
case 12:
config |= MAX6650_CFG_V12;
break;
default:
dev_err(dev, "illegal value for fan_voltage (%d)\n", voltage);
}
switch (prescale) {
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(dev, "illegal value for prescaler (%d)\n", prescale);
}
dev_info(dev, "Fan voltage: %dV, prescaler: %d.\n",
(config & MAX6650_CFG_V12) ? 12 : 5,
1 << (config & MAX6650_CFG_PRESCALER_MASK));
if (i2c_smbus_write_byte_data(client, MAX6650_REG_CONFIG, config)) {
dev_err(dev, "Config write error, aborting.\n");
return err;
}
data->config = config;
data->count = i2c_smbus_read_byte_data(client, MAX6650_REG_COUNT);
if (!of_property_read_u32(client->dev.of_node, "maxim,fan-target-rpm",
&target_rpm)) {
max6650_set_target(data, target_rpm);
max6650_set_operating_mode(data, MAX6650_CFG_MODE_CLOSED_LOOP);
}
return 0;
}
static int max6650_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct device *dev = &client->dev;
const struct of_device_id *of_id =
of_match_device(of_match_ptr(max6650_dt_match), dev);
struct max6650_data *data;
struct device *hwmon_dev;
int err;
data = devm_kzalloc(dev, sizeof(struct max6650_data), GFP_KERNEL);
if (!data)
return -ENOMEM;
data->client = client;
mutex_init(&data->update_lock);
data->nr_fans = of_id ? (int)(uintptr_t)of_id->data : id->driver_data;
/*
* Initialize the max6650 chip
*/
err = max6650_init_client(data, client);
if (err)
return err;
data->groups[0] = &max6650_group;
/* 3 additional fan inputs for the MAX6651 */
if (data->nr_fans == 4)
data->groups[1] = &max6651_group;
hwmon_dev = devm_hwmon_device_register_with_groups(dev,
client->name, data,
data->groups);
return PTR_ERR_OR_ZERO(hwmon_dev);
}
static const struct i2c_device_id max6650_id[] = {
{ "max6650", 1 },
{ "max6651", 4 },
{ }
};
MODULE_DEVICE_TABLE(i2c, max6650_id);
static struct i2c_driver max6650_driver = {
.driver = {
.name = "max6650",
.of_match_table = of_match_ptr(max6650_dt_match),
},
.probe = max6650_probe,
.id_table = max6650_id,
};
module_i2c_driver(max6650_driver);
MODULE_AUTHOR("Hans J. Koch");
MODULE_DESCRIPTION("MAX6650 sensor driver");
MODULE_LICENSE("GPL");
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