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drivers/hwmon/adm1021.c: add low_power support for adm1021 driver 

Occasionally it is helpful to be able to turn a temperature sensor off
(for example if it's making unwanted electrical noise).  This patch
adds a sysfs node to put any adm1021 compatible device into low power mode.

Signed-off-by: Michael Abbott <michael.abbott@diamond.ac.uk>
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:
Michael Abbott 2009-09-21 17:04:47 -07:00 committed by Linus Torvalds
parent f266889517
commit 905ffdc35e
1 changed files with 32 additions and 0 deletions
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32
drivers/hwmon/adm1021.c
View File

@ -83,6 +83,7 @@ struct adm1021_data {
struct mutex update_lock;
char valid; /* !=0 if following fields are valid */
char low_power; /* !=0 if device in low power mode */
unsigned long last_updated; /* In jiffies */
int temp_max[2]; /* Register values */
@ -213,6 +214,35 @@ static ssize_t set_temp_min(struct device *dev,
return count;
}
static ssize_t show_low_power(struct device *dev,
struct device_attribute *devattr, char *buf)
{
struct adm1021_data *data = adm1021_update_device(dev);
return sprintf(buf, "%d\n", data->low_power);
}
static ssize_t set_low_power(struct device *dev,
struct device_attribute *devattr,
const char *buf, size_t count)
{
struct i2c_client *client = to_i2c_client(dev);
struct adm1021_data *data = i2c_get_clientdata(client);
int low_power = simple_strtol(buf, NULL, 10) != 0;
mutex_lock(&data->update_lock);
if (low_power != data->low_power) {
int config = i2c_smbus_read_byte_data(
client, ADM1021_REG_CONFIG_R);
data->low_power = low_power;
i2c_smbus_write_byte_data(client, ADM1021_REG_CONFIG_W,
(config & 0xBF) | (low_power << 6));
}
mutex_unlock(&data->update_lock);
return count;
}
static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL, 0);
static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, show_temp_max,
set_temp_max, 0);
@ -230,6 +260,7 @@ static SENSOR_DEVICE_ATTR(temp2_min_alarm, S_IRUGO, show_alarm, NULL, 3);
static SENSOR_DEVICE_ATTR(temp2_fault, S_IRUGO, show_alarm, NULL, 2);
static DEVICE_ATTR(alarms, S_IRUGO, show_alarms, NULL);
static DEVICE_ATTR(low_power, S_IWUSR | S_IRUGO, show_low_power, set_low_power);
static struct attribute *adm1021_attributes[] = {
&sensor_dev_attr_temp1_max.dev_attr.attr,
@ -244,6 +275,7 @@ static struct attribute *adm1021_attributes[] = {
&sensor_dev_attr_temp2_min_alarm.dev_attr.attr,
&sensor_dev_attr_temp2_fault.dev_attr.attr,
&dev_attr_alarms.attr,
&dev_attr_low_power.attr,
NULL
};