[PATCH v2 3/7] ACPI: Documentation: Document acpi_dev_state_d0()

[Sakari Ailus <sakari.ailus@linux.intel.com>]

Document that acpi_dev_state_d0() can be used to tell if the device was
powered on for probe.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
---
 Documentation/firmware-guide/acpi/non-d0-probe.rst | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/Documentation/firmware-guide/acpi/non-d0-probe.rst b/Documentation/firmware-guide/acpi/non-d0-probe.rst
index 7afd16701a02..815bcc8db69f 100644
--- a/Documentation/firmware-guide/acpi/non-d0-probe.rst
+++ b/Documentation/firmware-guide/acpi/non-d0-probe.rst
@@ -24,6 +24,14 @@ there's a problem with the device, the driver likely probes just fine but the
 first user will find out the device doesn't work, instead of a failure at probe
 time. This feature should thus be used sparingly.
 
+ACPI framework
+--------------
+
+Use the Linux ACPI framework function :c:func:`acpi_dev_state_d0()` to tell
+whether the device was powered on for probe. :c:func:`acpi_dev_state_d0()`
+returns true if the device is powered on, false otherwise. For non-ACPI backed
+devices it returns true always.
+
 I²C
 ---
 
-- 
2.39.2