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Commit 905ffdc3 authored by Michael Abbott's avatar Michael Abbott Committed by Linus Torvalds
Browse files

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: default avatarMichael Abbott <michael.abbott@diamond.ac.uk>
Cc: Jean Delvare <khali@linux-fr.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent f2668895

drivers/hwmon/adm1021.c

+32 −0
Original line number Diff line number Diff line
@@ -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

};