[PATCH 1/2] of: Add of_machine_compatible_match()

[Michael Ellerman <mpe@ellerman.id.au>]

We have of_machine_is_compatible() to check if a machine is compatible
with a single compatible string. However some code is able to support
multiple compatible boards, and so wants to check for one of many
compatible strings.

So add of_machine_compatible_match() which takes a NULL terminated
array of compatible strings to check against the root node's
compatible property.

Compared to an open coded match this is slightly more self
documenting, and also avoids the caller needing to juggle the root
node either directly or via of_find_node_by_path().

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
---
 drivers/of/base.c  | 21 +++++++++++++++++++++
 include/linux/of.h |  6 ++++++
 2 files changed, 27 insertions(+)

diff --git a/drivers/of/base.c b/drivers/of/base.c
index 848f549164cd..603716ba8513 100644
--- a/drivers/of/base.c
+++ b/drivers/of/base.c
@@ -505,6 +505,27 @@ int of_device_compatible_match(struct device_node *device,
 	return score;
 }
 
+/**
+ * of_machine_compatible_match - Test root of device tree against a compatible array
+ * @compats: NULL terminated array of compatible strings to look for in root node's compatible property.
+ *
+ * Returns true if the root node has any of the given compatible values in its
+ * compatible property.
+ */
+bool of_machine_compatible_match(const char *const *compats)
+{
+	struct device_node *root;
+	int rc = 0;
+
+	root = of_node_get(of_root);
+	if (root) {
+		rc = of_device_compatible_match(root, compats);
+		of_node_put(root);
+	}
+
+	return rc != 0;
+}
+
 /**
  * of_machine_is_compatible - Test root of device tree for a given compatible value
  * @compat: compatible string to look for in root node's compatible property.
diff --git a/include/linux/of.h b/include/linux/of.h
index 4d25e4f952d9..05e3e23a3a57 100644
--- a/include/linux/of.h
+++ b/include/linux/of.h
@@ -389,6 +389,7 @@ extern int of_alias_get_id(struct device_node *np, const char *stem);
 extern int of_alias_get_highest_id(const char *stem);
 
 extern int of_machine_is_compatible(const char *compat);
+extern bool of_machine_compatible_match(const char *const *compats);
 
 extern int of_add_property(struct device_node *np, struct property *prop);
 extern int of_remove_property(struct device_node *np, struct property *prop);
@@ -877,6 +878,11 @@ static inline int of_machine_is_compatible(const char *compat)
 	return 0;
 }
 
+static inline bool of_machine_compatible_match(const char *const *compats)
+{
+	return false;
+}
+
 static inline bool of_console_check(const struct device_node *dn, const char *name, int index)
 {
 	return false;
-- 
2.14.1