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.
In low power mode a special single-shot command is required to take a
measurement: this is not implemented in this patch.
Signed-off-by: Michael Abbott <michael.abbott at diamond.ac.uk>
---
drivers/hwmon/adm1021.c | 33 +++++++++++++++++++++++++++++++++
1 files changed, 33 insertions(+), 0 deletions(-)
diff --git a/drivers/hwmon/adm1021.c b/drivers/hwmon/adm1021.c
index b11e06f..ba7a423 100644
--- a/drivers/hwmon/adm1021.c
+++ b/drivers/hwmon/adm1021.c
@@ -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 */
s8 temp_max[2]; /* Register values */
@@ -216,6 +217,35 @@ 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);
@@ -233,6 +263,8 @@ 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,
@@ -247,6 +279,7 @@ 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
};
--
1.6.1.3
