diff options
Diffstat (limited to 'drivers/acpi/device_pm.c')
| -rw-r--r-- | drivers/acpi/device_pm.c | 26 |
1 files changed, 26 insertions, 0 deletions
diff --git a/drivers/acpi/device_pm.c b/drivers/acpi/device_pm.c index 0028b6b51c87..19b33c028f35 100644 --- a/drivers/acpi/device_pm.c +++ b/drivers/acpi/device_pm.c @@ -1400,4 +1400,30 @@ bool acpi_storage_d3(struct device *dev) } EXPORT_SYMBOL_GPL(acpi_storage_d3); +/** + * acpi_dev_state_d0 - Tell if the device is in D0 power state + * @dev: Physical device the ACPI power state of which to check + * + * On a system without ACPI, return true. On a system with ACPI, return true if + * the current ACPI power state of the device is D0, or false otherwise. + * + * Note that the power state of a device is not well-defined after it has been + * passed to acpi_device_set_power() and before that function returns, so it is + * not valid to ask for the ACPI power state of the device in that time frame. + * + * This function is intended to be used in a driver's probe or remove + * function. See Documentation/firmware-guide/acpi/low-power-probe.rst for + * more information. + */ +bool acpi_dev_state_d0(struct device *dev) +{ + struct acpi_device *adev = ACPI_COMPANION(dev); + + if (!adev) + return true; + + return adev->power.state == ACPI_STATE_D0; +} +EXPORT_SYMBOL_GPL(acpi_dev_state_d0); + #endif /* CONFIG_PM */ |