[PATCH v1 2/6] device property: Add fwnode_property_match_property_string()

[Andy Shevchenko <andriy.shevchenko@linux.intel.com>]

Sometimes the users want to match the single value string property
against an array of predefined strings. Create a helper for them.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
 drivers/base/property.c  | 35 +++++++++++++++++++++++++++++++++++
 include/linux/property.h | 12 ++++++++++++
 2 files changed, 47 insertions(+)

diff --git a/drivers/base/property.c b/drivers/base/property.c
index 3bb9505f1631..8f8e2a6816bc 100644
--- a/drivers/base/property.c
+++ b/drivers/base/property.c
@@ -498,6 +498,41 @@ int fwnode_property_match_string(const struct fwnode_handle *fwnode,
 }
 EXPORT_SYMBOL_GPL(fwnode_property_match_string);
 
+/**
+ * fwnode_property_match_property_string - find a property string value in an array and return index
+ * @fwnode: Firmware node to get the property of
+ * @propname: Name of the property holding the string value
+ * @array: String array to search in
+ * @n: Size of the @array
+ *
+ * Find a property string value in a given @array and if it is found return
+ * the index back.
+ *
+ * Return: index, starting from %0, if the string value was found in the @array (success),
+ *	   %-ENOENT when the string value was not found in the @array,
+ *	   %-EINVAL if given arguments are not valid,
+ *	   %-ENODATA if the property does not have a value,
+ *	   %-EPROTO or %-EILSEQ if the property is not a string,
+ *	   %-ENXIO if no suitable firmware interface is present.
+ */
+int fwnode_property_match_property_string(const struct fwnode_handle *fwnode,
+	const char *propname, const char * const *array, size_t n)
+{
+	const char *string;
+	int ret;
+
+	ret = fwnode_property_read_string(fwnode, propname, &string);
+	if (ret)
+		return ret;
+
+	ret = match_string(array, n, string);
+	if (ret < 0)
+		ret = -ENOENT;
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(fwnode_property_match_property_string);
+
 /**
  * fwnode_property_get_reference_args() - Find a reference with arguments
  * @fwnode:	Firmware node where to look for the reference
diff --git a/include/linux/property.h b/include/linux/property.h
index 8c3c6685a2ae..11f3ad6814f2 100644
--- a/include/linux/property.h
+++ b/include/linux/property.h
@@ -97,6 +97,18 @@ static inline bool device_is_compatible(const struct device *dev, const char *co
 	return fwnode_device_is_compatible(dev_fwnode(dev), compat);
 }
 
+int fwnode_property_match_property_string(const struct fwnode_handle *fwnode,
+					  const char *propname,
+					  const char * const *array, size_t n);
+
+static inline
+int device_property_match_property_string(const struct device *dev,
+					  const char *propname,
+					  const char * const *array, size_t n)
+{
+	return fwnode_property_match_property_string(dev_fwnode(dev), propname, array, n);
+}
+
 int fwnode_property_get_reference_args(const struct fwnode_handle *fwnode,
 				       const char *prop, const char *nargs_prop,
 				       unsigned int nargs, unsigned int index,
-- 
2.40.0.1.gaa8946217a0b