hwmon: (emc1403) Add power support

Add back the power interface we lost due to a slight misunderstanding of
the maintainers wishes.

Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>

drivers/hwmon/emc1403.c

@@ -89,6 +89,35 @@ static ssize_t store_temp(struct device *dev,
 	return count;
 }
 
+static ssize_t store_bit(struct device *dev,
+		struct device_attribute *attr, const char *buf, size_t count)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct thermal_data *data = i2c_get_clientdata(client);
+	struct sensor_device_attribute_2 *sda = to_sensor_dev_attr_2(attr);
+	unsigned long val;
+	int retval;
+
+	if (strict_strtoul(buf, 10, &val))
+		return -EINVAL;
+
+	mutex_lock(&data->mutex);
+	retval = i2c_smbus_read_byte_data(client, sda->nr);
+	if (retval < 0)
+		goto fail;
+
+	retval &= ~sda->index;
+	if (val)
+		retval |= sda->index;
+
+	retval = i2c_smbus_write_byte_data(client, sda->index, retval);
+	if (retval == 0)
+		retval = count;
+fail:
+	mutex_unlock(&data->mutex);
+	return retval;
+}
+
 static ssize_t show_hyst(struct device *dev,
 			struct device_attribute *attr, char *buf)
 {
@@ -200,6 +229,9 @@ static SENSOR_DEVICE_ATTR_2(temp3_crit_alarm, S_IRUGO,
 static SENSOR_DEVICE_ATTR(temp3_crit_hyst, S_IRUGO | S_IWUSR,
 	show_hyst, store_hyst, 0x1A);
 
+static SENSOR_DEVICE_ATTR_2(power_state, S_IRUGO | S_IWUSR,
+	show_bit, store_bit, 0x03, 0x40);
+
 static struct attribute *mid_att_thermal[] = {
 	&sensor_dev_attr_temp1_min.dev_attr.attr,
 	&sensor_dev_attr_temp1_max.dev_attr.attr,
@@ -225,6 +257,7 @@ static struct attribute *mid_att_thermal[] = {
 	&sensor_dev_attr_temp3_max_alarm.dev_attr.attr,
 	&sensor_dev_attr_temp3_crit_alarm.dev_attr.attr,
 	&sensor_dev_attr_temp3_crit_hyst.dev_attr.attr,
+	&sensor_dev_attr_power_state.dev_attr.attr,
 	NULL
 };