[PATCH 2/6] of: add function to check against a list of compatible strings

[heiko@sntech.de (Heiko Stübner)]

The basic of functions already provide a of_device_is_compatible to check
if a device's compatible property contains a specific one. But sometimes
it's also necessary to check if the device is compatible to one out of a
list of compatible devices.

Therefore add of_device_is_any_of that reuses the compatible check of
of_device_is_compatible but checks against a list of compatible strings
without the locking overhead of calling of_device_is_compatible multiple
times.

Signed-off-by: Heiko Stuebner <heiko@sntech.de>
---
 drivers/of/base.c  |   21 +++++++++++++++++++++
 include/linux/of.h |    2 ++
 2 files changed, 23 insertions(+)

diff --git a/drivers/of/base.c b/drivers/of/base.c
index 865d3f6..589f43e 100644
--- a/drivers/of/base.c
+++ b/drivers/of/base.c
@@ -366,6 +366,27 @@ int of_device_is_compatible(const struct device_node *device,
 EXPORT_SYMBOL(of_device_is_compatible);
 
 /**
+ * Checks if any of the given "compat" strings matches one of the strings
+ * in the device's "compatible" property.
+ */
+int of_device_is_any_of(const struct device_node *device,
+			const char * const *compat, int num) {
+	unsigned long flags;
+	int res = 0, i;
+
+	raw_spin_lock_irqsave(&devtree_lock, flags);
+	for (i = 0; i < num; i++) {
+		if (__of_device_is_compatible(device, compat[i])) {
+			res = 1;
+			break;
+		}
+	}
+	raw_spin_unlock_irqrestore(&devtree_lock, flags);
+	return res;
+}
+EXPORT_SYMBOL(of_device_is_any_of);
+
+/**
  * 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 f95aee3..5bf7c9a 100644
--- a/include/linux/of.h
+++ b/include/linux/of.h
@@ -262,6 +262,8 @@ extern int of_property_count_strings(struct device_node *np,
 				     const char *propname);
 extern int of_device_is_compatible(const struct device_node *device,
 				   const char *);
+extern int of_device_is_any_of(const struct device_node *device,
+			       const char * const *compat, int num);
 extern int of_device_is_available(const struct device_node *device);
 extern const void *of_get_property(const struct device_node *node,
 				const char *name,
-- 
1.7.10.4