Subject: [PATCH 1/7] of: base: Add of_count_phandle_with_fixed_args()

From: Richard Fitzgerald <[email-masked]>
Date: Wed, 14 Oct 2020 15:54:12 +0100

Add an equivalent of of_count_phandle_with_args() for fixed argument
sets, to pair with of_parse_phandle_with_fixed_args().

Signed-off-by: Richard Fitzgerald <[email-masked]>
---
 drivers/of/base.c  | 42 ++++++++++++++++++++++++++++++++++++++++++
 include/linux/of.h |  9 +++++++++
 2 files changed, 51 insertions(+)

diff --git a/drivers/of/base.c b/drivers/of/base.c
index ea44fea99813..45d8b0e65345 100644
--- a/drivers/of/base.c
+++ b/drivers/of/base.c
@@ -1772,6 +1772,48 @@ int of_count_phandle_with_args(const struct device_node *np, const char *list_na
 }
 EXPORT_SYMBOL(of_count_phandle_with_args);
 
+/**
+ * of_count_phandle_with_fixed_args() - Find the number of phandles references in a property
+ * @np:		pointer to a device tree node containing a list
+ * @list_name:	property name that contains a list
+ * @cell_count: number of argument cells following the phandle
+ *
+ * Returns the number of phandle + argument tuples within a property. It
+ * is a typical pattern to encode a list of phandle and variable
+ * arguments into a single property.
+ */
+int of_count_phandle_with_fixed_args(const struct device_node *np,
+				     const char *list_name,
+				     int cells_count)
+{
+	struct of_phandle_iterator it;
+	int rc, cur_index = 0;
+
+	if (!cells_count) {
+		const __be32 *list;
+		int size;
+
+		list = of_get_property(np, list_name, &size);
+		if (!list)
+			return -ENOENT;
+
+		return size / sizeof(*list);
+	}
+
+	rc = of_phandle_iterator_init(&it, np, list_name, NULL, cells_count);
+	if (rc)
+		return rc;
+
+	while ((rc = of_phandle_iterator_next(&it)) == 0)
+		cur_index += 1;
+
+	if (rc != -ENOENT)
+		return rc;
+
+	return cur_index;
+}
+EXPORT_SYMBOL(of_count_phandle_with_fixed_args);
+
 /**
  * __of_add_property - Add a property to a node without lock operations
  */
diff --git a/include/linux/of.h b/include/linux/of.h
index 5cf7ae0465d1..9f315da4e9da 100644
--- a/include/linux/of.h
+++ b/include/linux/of.h
@@ -377,6 +377,8 @@ extern int of_parse_phandle_with_fixed_args(const struct device_node *np,
 	struct of_phandle_args *out_args);
 extern int of_count_phandle_with_args(const struct device_node *np,
 	const char *list_name, const char *cells_name);
+extern int of_count_phandle_with_fixed_args(const struct device_node *np,
+	const char *list_name, int cells_count);
 
 /* phandle iterator functions */
 extern int of_phandle_iterator_init(struct of_phandle_iterator *it,
@@ -886,6 +888,13 @@ static inline int of_count_phandle_with_args(struct device_node *np,
 	return -ENOSYS;
 }
 
+static inline int of_count_phandle_with_fixed_args(const struct device_node *np,
+						   const char *list_name,
+						   int cells_count)
+{
+	return -ENOSYS;
+}
+
 static inline int of_phandle_iterator_init(struct of_phandle_iterator *it,
 					   const struct device_node *np,
 					   const char *list_name,
-- 
2.20.1

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