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adt7470: make automatic fan control really work

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It turns out that the adt7470's automatic fan control algorithm only works
when the temperature sensors get updated.  This in turn happens only when
someone tells the chip to read its temperature sensors.  Regrettably, this
means that we have to drive the chip periodically.

Signed-off-by: Darrick J. Wong <djwong@us.ibm.com>
Cc: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Darrick J. Wong 2009-01-06 14:41:34 -08:00 committed by Linus Torvalds
parent 2f22d5dff6
commit 89fac11cb3
2 changed files with 142 additions and 33 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

19
Documentation/hwmon/adt7470
View file

@ -31,15 +31,11 @@ Each of the measured inputs (temperature, fan speed) has corresponding high/low
limit values. The ADT7470 will signal an ALARM if any measured value exceeds
either limit.
The ADT7470 DOES NOT sample all inputs continuously. A single pin on the
ADT7470 is connected to a multitude of thermal diodes, but the chip must be
instructed explicitly to read the multitude of diodes. If you want to use
automatic fan control mode, you must manually read any of the temperature
sensors or the fan control algorithm will not run. The chip WILL NOT DO THIS
AUTOMATICALLY; this must be done from userspace. This may be a bug in the chip
design, given that many other AD chips take care of this. The driver will not
read the registers more often than once every 5 seconds. Further,
configuration data is only read once per minute.
The ADT7470 samples all inputs continuously. A kernel thread is started up for
the purpose of periodically querying the temperature sensors, thus allowing the
automatic fan pwm control to set the fan speed. The driver will not read the
registers more often than once every 5 seconds. Further, configuration data is
only read once per minute.
Special Features
----------------
@ -72,5 +68,6 @@ pwm#_auto_point2_temp.
Notes
-----
As stated above, the temperature inputs must be read periodically from
userspace in order for the automatic pwm algorithm to run.
The temperature inputs no longer need to be read periodically from userspace in
order for the automatic pwm algorithm to run. This was the case for earlier
versions of the driver.

154
drivers/hwmon/adt7470.c
View file

@ -28,6 +28,7 @@
#include <linux/mutex.h>
#include <linux/delay.h>
#include <linux/log2.h>
#include <linux/kthread.h>
/* Addresses to scan */
static const unsigned short normal_i2c[] = { 0x2C, 0x2E, 0x2F, I2C_CLIENT_END };
@ -132,6 +133,9 @@ I2C_CLIENT_INSMOD_1(adt7470);
/* Wait at least 200ms per sensor for 10 sensors */
#define TEMP_COLLECTION_TIME 2000
/* auto update thing won't fire more than every 2s */
#define AUTO_UPDATE_INTERVAL 2000
/* datasheet says to divide this number by the fan reading to get fan rpm */
#define FAN_PERIOD_TO_RPM(x) ((90000 * 60) / (x))
#define FAN_RPM_TO_PERIOD FAN_PERIOD_TO_RPM
@ -148,6 +152,7 @@ struct adt7470_data {
unsigned long limits_last_updated; /* In jiffies */
int num_temp_sensors; /* -1 = probe */
int temperatures_probed;
s8 temp[ADT7470_TEMP_COUNT];
s8 temp_min[ADT7470_TEMP_COUNT];
@ -164,6 +169,10 @@ struct adt7470_data {
u8 pwm_min[ADT7470_PWM_COUNT];
s8 pwm_tmin[ADT7470_PWM_COUNT];
u8 pwm_auto_temp[ADT7470_PWM_COUNT];
struct task_struct *auto_update;
struct completion auto_update_stop;
unsigned int auto_update_interval;
};
static int adt7470_probe(struct i2c_client *client,
@ -221,19 +230,13 @@ static void adt7470_init_client(struct i2c_client *client)
}
}
static struct adt7470_data *adt7470_update_device(struct device *dev)
/* Probe for temperature sensors. Assumes lock is held */
static int adt7470_read_temperatures(struct i2c_client *client,
struct adt7470_data *data)
{
struct i2c_client *client = to_i2c_client(dev);
struct adt7470_data *data = i2c_get_clientdata(client);
unsigned long local_jiffies = jiffies;
u8 cfg, pwm[4], pwm_cfg[2];
unsigned long res;
int i;
mutex_lock(&data->lock);
if (time_before(local_jiffies, data->sensors_last_updated +
SENSOR_REFRESH_INTERVAL)
&& data->sensors_valid)
goto no_sensor_update;
u8 cfg, pwm[4], pwm_cfg[2];
/* save pwm[1-4] config register */
pwm_cfg[0] = i2c_smbus_read_byte_data(client, ADT7470_REG_PWM_CFG(0));
@ -259,7 +262,7 @@ static struct adt7470_data *adt7470_update_device(struct device *dev)
i2c_smbus_write_byte_data(client, ADT7470_REG_CFG, cfg);
/* Delay is 200ms * number of temp sensors. */
msleep((data->num_temp_sensors >= 0 ?
res = msleep_interruptible((data->num_temp_sensors >= 0 ?
data->num_temp_sensors * 200 :
TEMP_COLLECTION_TIME));
@ -272,16 +275,82 @@ static struct adt7470_data *adt7470_update_device(struct device *dev)
i2c_smbus_write_byte_data(client, ADT7470_REG_PWM_CFG(0), pwm_cfg[0]);
i2c_smbus_write_byte_data(client, ADT7470_REG_PWM_CFG(2), pwm_cfg[1]);
if (res) {
printk(KERN_ERR "ha ha, interrupted");
return -EAGAIN;
}
/* Only count fans if we have to */
if (data->num_temp_sensors >= 0)
return 0;
for (i = 0; i < ADT7470_TEMP_COUNT; i++) {
data->temp[i] = i2c_smbus_read_byte_data(client,
ADT7470_TEMP_REG(i));
if (data->temp[i])
data->num_temp_sensors = i + 1;
}
data->temperatures_probed = 1;
return 0;
}
static int adt7470_update_thread(void *p)
{
struct i2c_client *client = p;
struct adt7470_data *data = i2c_get_clientdata(client);
while (!kthread_should_stop()) {
mutex_lock(&data->lock);
adt7470_read_temperatures(client, data);
mutex_unlock(&data->lock);
if (kthread_should_stop())
break;
msleep_interruptible(data->auto_update_interval);
}
complete_all(&data->auto_update_stop);
return 0;
}
static struct adt7470_data *adt7470_update_device(struct device *dev)
{
struct i2c_client *client = to_i2c_client(dev);
struct adt7470_data *data = i2c_get_clientdata(client);
unsigned long local_jiffies = jiffies;
u8 cfg;
int i;
int need_sensors = 1;
int need_limits = 1;
/*
* Figure out if we need to update the shadow registers.
* Lockless means that we may occasionally report out of
* date data.
*/
if (time_before(local_jiffies, data->sensors_last_updated +
SENSOR_REFRESH_INTERVAL) &&
data->sensors_valid)
need_sensors = 0;
if (time_before(local_jiffies, data->limits_last_updated +
LIMIT_REFRESH_INTERVAL) &&
data->limits_valid)
need_limits = 0;
if (!need_sensors && !need_limits)
return data;
mutex_lock(&data->lock);
if (!need_sensors)
goto no_sensor_update;
if (!data->temperatures_probed)
adt7470_read_temperatures(client, data);
else
for (i = 0; i < ADT7470_TEMP_COUNT; i++)
data->temp[i] = i2c_smbus_read_byte_data(client,
ADT7470_TEMP_REG(i));
/* Figure out the number of temp sensors */
if (data->num_temp_sensors < 0)
for (i = 0; i < ADT7470_TEMP_COUNT; i++)
if (data->temp[i])
data->num_temp_sensors = i + 1;
for (i = 0; i < ADT7470_FAN_COUNT; i++)
data->fan[i] = adt7470_read_word_data(client,
ADT7470_REG_FAN(i));
@ -329,9 +398,7 @@ static struct adt7470_data *adt7470_update_device(struct device *dev)
data->sensors_valid = 1;
no_sensor_update:
if (time_before(local_jiffies, data->limits_last_updated +
LIMIT_REFRESH_INTERVAL)
&& data->limits_valid)
if (!need_limits)
goto out;
for (i = 0; i < ADT7470_TEMP_COUNT; i++) {
@ -365,6 +432,35 @@ out:
return data;
}
static ssize_t show_auto_update_interval(struct device *dev,
struct device_attribute *devattr,
char *buf)
{
struct adt7470_data *data = adt7470_update_device(dev);
return sprintf(buf, "%d\n", data->auto_update_interval);
}
static ssize_t set_auto_update_interval(struct device *dev,
struct device_attribute *devattr,
const char *buf,
size_t count)
{
struct i2c_client *client = to_i2c_client(dev);
struct adt7470_data *data = i2c_get_clientdata(client);
long temp;
if (strict_strtol(buf, 10, &temp))
return -EINVAL;
temp = SENSORS_LIMIT(temp, 0, 60000);
mutex_lock(&data->lock);
data->auto_update_interval = temp;
mutex_unlock(&data->lock);
return count;
}
static ssize_t show_num_temp_sensors(struct device *dev,
struct device_attribute *devattr,
char *buf)
@ -389,6 +485,8 @@ static ssize_t set_num_temp_sensors(struct device *dev,
mutex_lock(&data->lock);
data->num_temp_sensors = temp;
if (temp < 0)
data->temperatures_probed = 0;
mutex_unlock(&data->lock);
return count;
@ -862,6 +960,8 @@ static ssize_t show_alarm(struct device *dev,
static DEVICE_ATTR(alarm_mask, S_IRUGO, show_alarm_mask, NULL);
static DEVICE_ATTR(num_temp_sensors, S_IWUSR | S_IRUGO, show_num_temp_sensors,
set_num_temp_sensors);
static DEVICE_ATTR(auto_update_interval, S_IWUSR | S_IRUGO,
show_auto_update_interval, set_auto_update_interval);
static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, show_temp_max,
set_temp_max, 0);
@ -1035,6 +1135,7 @@ static struct attribute *adt7470_attr[] =
{
&dev_attr_alarm_mask.attr,
&dev_attr_num_temp_sensors.attr,
&dev_attr_auto_update_interval.attr,
&sensor_dev_attr_temp1_max.dev_attr.attr,
&sensor_dev_attr_temp2_max.dev_attr.attr,
&sensor_dev_attr_temp3_max.dev_attr.attr,
@ -1168,6 +1269,7 @@ static int adt7470_probe(struct i2c_client *client,
}
data->num_temp_sensors = -1;
data->auto_update_interval = AUTO_UPDATE_INTERVAL;
i2c_set_clientdata(client, data);
mutex_init(&data->lock);
@ -1188,8 +1290,16 @@ static int adt7470_probe(struct i2c_client *client,
goto exit_remove;
}
init_completion(&data->auto_update_stop);
data->auto_update = kthread_run(adt7470_update_thread, client,
dev_name(data->hwmon_dev));
if (IS_ERR(data->auto_update))
goto exit_unregister;
return 0;
exit_unregister:
hwmon_device_unregister(data->hwmon_dev);
exit_remove:
sysfs_remove_group(&client->dev.kobj, &data->attrs);
exit_free:
@ -1202,6 +1312,8 @@ static int adt7470_remove(struct i2c_client *client)
{
struct adt7470_data *data = i2c_get_clientdata(client);
kthread_stop(data->auto_update);
wait_for_completion(&data->auto_update_stop);
hwmon_device_unregister(data->hwmon_dev);
sysfs_remove_group(&client->dev.kobj, &data->attrs);
kfree(data);