linux-stable/drivers/hwmon/max6650.c
Mike Looijmans 20005cc58d hwmon: (max6650) Allow fan shutdown and initial rpm target
The fan can be stopped by writing "3" to pwm1_enable in sysfs.

Add devicetree property for early initialization of the fan controller
to prevent overheating, for example when resetting the board while the
fan was completely turned off.

Also improve error reporting, I2C failures were ignored while writing
new values.

Signed-off-by: Mike Looijmans <mike.looijmans@topic.nl>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2016-09-08 21:34:17 -07:00

754 lines
19 KiB
C

/*
* 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 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 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 set_target(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 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 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 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, 3, 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 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 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 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(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 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");