ACPI / PM: Expose power states of ACPI devices to user space
Make it possible to retrieve the current power state of a device with
ACPI power management from user space via sysfs by adding two new
attributes, power_state and real_power_state, to the sysfs directory
associated with the struct acpi_device object representing the
device's ACPI node.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index 8b3b188..9761d58 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -178,6 +178,32 @@
}
EXPORT_SYMBOL(acpi_bus_hot_remove_device);
+static ssize_t real_power_state_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct acpi_device *adev = to_acpi_device(dev);
+ int state;
+ int ret;
+
+ ret = acpi_device_get_power(adev, &state);
+ if (ret)
+ return ret;
+
+ return sprintf(buf, "%s\n", acpi_power_state_string(state));
+}
+
+static DEVICE_ATTR(real_power_state, 0444, real_power_state_show, NULL);
+
+static ssize_t power_state_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct acpi_device *adev = to_acpi_device(dev);
+
+ return sprintf(buf, "%s\n", acpi_power_state_string(adev->power.state));
+}
+
+static DEVICE_ATTR(power_state, 0444, power_state_show, NULL);
+
static ssize_t
acpi_eject_store(struct device *d, struct device_attribute *attr,
const char *buf, size_t count)
@@ -369,8 +395,22 @@
* hot-removal function from userland.
*/
status = acpi_get_handle(dev->handle, "_EJ0", &temp);
- if (ACPI_SUCCESS(status))
+ if (ACPI_SUCCESS(status)) {
result = device_create_file(&dev->dev, &dev_attr_eject);
+ if (result)
+ return result;
+ }
+
+ if (dev->flags.power_manageable) {
+ result = device_create_file(&dev->dev, &dev_attr_power_state);
+ if (result)
+ return result;
+
+ if (dev->power.flags.power_resources)
+ result = device_create_file(&dev->dev,
+ &dev_attr_real_power_state);
+ }
+
end:
return result;
}
@@ -380,6 +420,13 @@
acpi_status status;
acpi_handle temp;
+ if (dev->flags.power_manageable) {
+ device_remove_file(&dev->dev, &dev_attr_power_state);
+ if (dev->power.flags.power_resources)
+ device_remove_file(&dev->dev,
+ &dev_attr_real_power_state);
+ }
+
/*
* If device has _STR, remove 'description' file
*/