ACPI / PM: Provide device PM functions operating on struct acpi_device

If the caller of acpi_bus_set_power() already has a pointer to the
struct acpi_device object corresponding to the device in question, it
doesn't make sense for it to go through acpi_bus_get_device(), which
may be costly, because it involves acquiring the global ACPI
namespace mutex.

For this reason, export the function operating on struct acpi_device
objects used internally by acpi_bus_set_power(), so that it may be
called instead of acpi_bus_set_power() in the above case, and change
its name to acpi_device_set_power().

Additionally, introduce two inline wrappers for checking ACPI PM
capabilities of devices represented by struct acpi_device objects.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

1 files changed, 12 insertions, 3 deletions

diff --git a/drivers/acpi/bus.c b/drivers/acpi/bus.c
index d59175efc428..07a20ee3e690 100644
--- a/drivers/acpi/bus.c
+++ b/drivers/acpi/bus.c
@@ -257,7 +257,15 @@ static int __acpi_bus_get_power(struct acpi_device *device, int *state)
 }
 
 
-static int __acpi_bus_set_power(struct acpi_device *device, int state)
+/**
+ * acpi_device_set_power - Set power state of an ACPI device.
+ * @device: Device to set the power state of.
+ * @state: New power state to set.
+ *
+ * Callers must ensure that the device is power manageable before using this
+ * function.
+ */
+int acpi_device_set_power(struct acpi_device *device, int state)
 {
 	int result = 0;
 	acpi_status status = AE_OK;
@@ -341,6 +349,7 @@ static int __acpi_bus_set_power(struct acpi_device *device, int state)
 
 	return result;
 }
+EXPORT_SYMBOL(acpi_device_set_power);
 
 
 int acpi_bus_set_power(acpi_handle handle, int state)
@@ -359,7 +368,7 @@ int acpi_bus_set_power(acpi_handle handle, int state)
 		return -ENODEV;
 	}
 
-	return __acpi_bus_set_power(device, state);
+	return acpi_device_set_power(device, state);
 }
 EXPORT_SYMBOL(acpi_bus_set_power);
 
@@ -402,7 +411,7 @@ int acpi_bus_update_power(acpi_handle handle, int *state_p)
 	if (result)
 		return result;
 
-	result = __acpi_bus_set_power(device, state);
+	result = acpi_device_set_power(device, state);
 	if (!result && state_p)
 		*state_p = state;