[net-next PATCH v4 09/15] device property: Introduce fwnode_get_id()

[Calvin Johnson]

Using fwnode_get_id(), get the reg property value for DT node
or get the _ADR object value for ACPI node.

Signed-off-by: Calvin Johnson <calvin.johnson@xxxxxxxxxxx>
---

Changes in v4:
- Improve code structure to handle all cases

Changes in v3:
- Modified to retrieve reg property value for ACPI as well
- Resolved compilation issue with CONFIG_ACPI = n
- Added more info into documentation

Changes in v2: None

 drivers/base/property.c  | 34 ++++++++++++++++++++++++++++++++++
 include/linux/property.h |  1 +
 2 files changed, 35 insertions(+)

diff --git a/drivers/base/property.c b/drivers/base/property.c
index 35b95c6ac0c6..f0581bbf7a4b 100644
--- a/drivers/base/property.c
+++ b/drivers/base/property.c
@@ -580,6 +580,40 @@ const char *fwnode_get_name_prefix(const struct fwnode_handle *fwnode)
 	return fwnode_call_ptr_op(fwnode, get_name_prefix);
 }
 
+/**
+ * fwnode_get_id - Get the id of a fwnode.
+ * @fwnode: firmware node
+ * @id: id of the fwnode
+ *
+ * This function provides the id of a fwnode which can be either
+ * DT or ACPI node. For ACPI, "reg" property value, if present will
+ * be provided or else _ADR value will be provided.
+ * Returns 0 on success or a negative errno.
+ */
+int fwnode_get_id(struct fwnode_handle *fwnode, u32 *id)
+{
+#ifdef CONFIG_ACPI
+	unsigned long long adr;
+	acpi_status status;
+#endif
+	int ret;
+
+	ret = fwnode_property_read_u32(fwnode, "reg", id);
+	if (ret) {
+#ifdef CONFIG_ACPI
+		status = acpi_evaluate_integer(ACPI_HANDLE_FWNODE(fwnode),
+					       METHOD_NAME__ADR, NULL, &adr);
+		if (ACPI_FAILURE(status))
+			return -EINVAL;
+		*id = (u32)adr;
+#else
+		return ret;
+#endif
+	}
+	return 0;
+}
+EXPORT_SYMBOL_GPL(fwnode_get_id);
+
 /**
  * fwnode_get_parent - Return parent firwmare node
  * @fwnode: Firmware whose parent is retrieved
diff --git a/include/linux/property.h b/include/linux/property.h
index 0a9001fe7aea..3f41475f010b 100644
--- a/include/linux/property.h
+++ b/include/linux/property.h
@@ -82,6 +82,7 @@ struct fwnode_handle *fwnode_find_reference(const struct fwnode_handle *fwnode,
 
 const char *fwnode_get_name(const struct fwnode_handle *fwnode);
 const char *fwnode_get_name_prefix(const struct fwnode_handle *fwnode);
+int fwnode_get_id(struct fwnode_handle *fwnode, u32 *id);
 struct fwnode_handle *fwnode_get_parent(const struct fwnode_handle *fwnode);
 struct fwnode_handle *fwnode_get_next_parent(
 	struct fwnode_handle *fwnode);
-- 
2.17.1