[PATCH v3 1/6] of: base: Add of_count_phandle_with_fixed_args()

From: Richard Fitzgerald <rf@opensource•cirrus.com>
To: <broonie@kernel•org>, <robh+dt@kernel•org>,
	<kuninori.morimoto.gx@renesas•com>, <nsaenzjulienne@suse•de>
Cc: devicetree@vger•kernel.org, alsa-devel@alsa-project•org,
	patches@opensource•cirrus.com, linux-kernel@vger•kernel.org,
	Richard Fitzgerald <rf@opensource•cirrus.com>,
	bcm-kernel-feedback-list@broadcom•com,
	linux-rpi-kernel@lists•infradead.org,
	linux-arm-kernel@lists•infradead.org
Subject: [PATCH v3 1/6] of: base: Add of_count_phandle_with_fixed_args()
Date: Thu, 17 Dec 2020 15:41:37 +0000	[thread overview]
Message-ID: <20201217154142.24301-2-rf@opensource.cirrus.com> (raw)
In-Reply-To: <20201217154142.24301-1-rf@opensource.cirrus.com>

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

The existing of_count_phandle_with_args() is modified to be a
private function that handles both cases and the public functions
are trivial wrappers round that.

Signed-off-by: Richard Fitzgerald <rf@opensource•cirrus.com>
Reviewed-by: Rob Herring <robh@kernel•org>
---
 drivers/of/base.c  | 73 +++++++++++++++++++++++++++++++---------------
 include/linux/of.h |  9 ++++++
 2 files changed, 59 insertions(+), 23 deletions(-)

diff --git a/drivers/of/base.c b/drivers/of/base.c
index 161a23631472..c5ff2524bf40 100644
--- a/drivers/of/base.c
+++ b/drivers/of/base.c
@@ -1720,34 +1720,22 @@ int of_parse_phandle_with_fixed_args(const struct device_node *np,
 }
 EXPORT_SYMBOL(of_parse_phandle_with_fixed_args);
 
-/**
- * of_count_phandle_with_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
- * @cells_name:	property name that specifies phandles' arguments count
- *
- * 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. The number of arguments is encoded
- * by a property in the phandle-target node. For example, a gpios
- * property would contain a list of GPIO specifies consisting of a
- * phandle and 1 or more arguments. The number of arguments are
- * determined by the #gpio-cells property in the node pointed to by the
- * phandle.
- */
-int of_count_phandle_with_args(const struct device_node *np, const char *list_name,
-				const char *cells_name)
+static int __of_count_phandle_with_args(const struct device_node *np,
+					const char *list_name,
+					const char *cells_name,
+					int cells_count)
 {
 	struct of_phandle_iterator it;
 	int rc, cur_index = 0;
 
 	/*
-	 * If cells_name is NULL we assume a cell count of 0. This makes
-	 * counting the phandles trivial as each 32bit word in the list is a
-	 * phandle and no arguments are to consider. So we don't iterate through
-	 * the list but just use the length to determine the phandle count.
+	 * If cells_count < 0 and cells_name is NULL we assume a cell count
+	 * of 0. A zero cell count makes counting the phandles trivial as each
+	 * 32bit word in the list is a phandle and no arguments are to consider.
+	 * So we don't iterate through the list but just use the length to
+	 * determine the phandle count.
 	 */
-	if (!cells_name) {
+	if ((cells_count < 0 && !cells_name) || cells_count == 0) {
 		const __be32 *list;
 		int size;
 
@@ -1758,7 +1746,7 @@ int of_count_phandle_with_args(const struct device_node *np, const char *list_na
 		return size / sizeof(*list);
 	}
 
-	rc = of_phandle_iterator_init(&it, np, list_name, cells_name, -1);
+	rc = of_phandle_iterator_init(&it, np, list_name, cells_name, cells_count);
 	if (rc)
 		return rc;
 
@@ -1770,8 +1758,47 @@ int of_count_phandle_with_args(const struct device_node *np, const char *list_na
 
 	return cur_index;
 }
+
+/**
+ * of_count_phandle_with_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
+ * @cells_name:	property name that specifies phandles' arguments count
+ *
+ * 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. The number of arguments is encoded
+ * by a property in the phandle-target node. For example, a gpios
+ * property would contain a list of GPIO specifies consisting of a
+ * phandle and 1 or more arguments. The number of arguments are
+ * determined by the #gpio-cells property in the node pointed to by the
+ * phandle.
+ */
+int of_count_phandle_with_args(const struct device_node *np, const char *list_name,
+				const char *cells_name)
+{
+	return __of_count_phandle_with_args(np, list_name, cells_name, -1);
+}
 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)
+{
+	return __of_count_phandle_with_args(np, list_name, NULL, cells_count);
+}
+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 5d51891cbf1a..2f28da56ec9b 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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