[PATCH 1/3] acpi: property: Let args be NULL in __acpi_node_get_property_reference

[Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx>]

fwnode_get_property_reference() may not be called with args argument NULL
on ACPI, OF already supports this. Add the missing NULL checks and
document this.

The purpose is to be able to count the references.

Signed-off-by: Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx>
---
 drivers/acpi/property.c | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/drivers/acpi/property.c b/drivers/acpi/property.c
index d60ee0510311..fa473fc2617b 100644
--- a/drivers/acpi/property.c
+++ b/drivers/acpi/property.c
@@ -879,7 +879,8 @@ static struct fwnode_handle *acpi_parse_string_ref(const struct fwnode_handle *f
  * @propname: Name of the property
  * @index: Index of the reference to return
  * @num_args: Maximum number of arguments after each reference
- * @args: Location to store the returned reference with optional arguments
+ * @args: Location to store the returned reference with optional arguments (may
+ *	  be NULL)
  *
  * Find property with @name, verifify that it is a package containing at least
  * one object reference and if so, store the ACPI device object pointer to the
@@ -937,8 +938,10 @@ int __acpi_node_get_property_reference(const struct fwnode_handle *fwnode,
 		if (!device)
 			return -EINVAL;
 
-		args->fwnode = acpi_fwnode_handle(device);
-		args->nargs = 0;
+		if (args) {
+			args->fwnode = acpi_fwnode_handle(device);
+			args->nargs = 0;
+		}
 
 		return 0;
 	case ACPI_TYPE_STRING:
@@ -949,8 +952,10 @@ int __acpi_node_get_property_reference(const struct fwnode_handle *fwnode,
 		if (!ref_fwnode)
 			return -EINVAL;
 
-		args->fwnode = ref_fwnode;
-		args->nargs = 0;
+		if (args) {
+			args->fwnode = ref_fwnode;
+			args->nargs = 0;
+		}
 
 		return 0;
 	case ACPI_TYPE_PACKAGE:
-- 
2.39.2