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From: Sakari Ailus <sakari.ailus@linux.intel.com>
To: Petr Mladek <pmladek@suse.com>,
	linux-kernel@vger.kernel.org, rafael@kernel.org
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
	linux-acpi@vger.kernel.org, devicetree@vger.kernel.org,
	Rob Herring <robh@kernel.org>,
	Heikki Krogerus <heikki.krogerus@linux.intel.com>
Subject: [PATCH v4 04/11] device property: Add functions for accessing node's parents
Date: Mon,  2 Sep 2019 11:32:33 +0300
Message-ID: <20190902083240.20367-5-sakari.ailus@linux.intel.com> (raw)
In-Reply-To: <20190902083240.20367-1-sakari.ailus@linux.intel.com>

Add two convenience functions for accessing node's parents:

fwnode_count_parents() returns the number of parent nodes a given node
has. fwnode_get_nth_parent() returns node's parent at a given distance
from the node itself.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
---
 drivers/base/property.c  | 46 ++++++++++++++++++++++++++++++++++++++++
 include/linux/property.h |  3 +++
 2 files changed, 49 insertions(+)

diff --git a/drivers/base/property.c b/drivers/base/property.c
index 3d9dffbe96378..d2461d79139f3 100644
--- a/drivers/base/property.c
+++ b/drivers/base/property.c
@@ -590,6 +590,52 @@ struct fwnode_handle *fwnode_get_next_parent(struct fwnode_handle *fwnode)
 }
 EXPORT_SYMBOL_GPL(fwnode_get_next_parent);
 
+/**
+ * fwnode_count_parents - Return the number of parents a node has
+ * @fwnode: The node the parents of which are to be counted
+ *
+ * Returns the number of parents a node has.
+ */
+unsigned int fwnode_count_parents(const struct fwnode_handle *fwnode)
+{
+	struct fwnode_handle *__fwnode;
+	unsigned int count;
+
+	__fwnode = fwnode_get_parent(fwnode);
+
+	for (count = 0; __fwnode; count++)
+		__fwnode = fwnode_get_next_parent(__fwnode);
+
+	return count;
+}
+EXPORT_SYMBOL_GPL(fwnode_count_parents);
+
+/**
+ * fwnode_get_nth_parent - Return an nth parent of a node
+ * @fwnode: The node the parent of which is requested
+ * @depth: Distance of the parent from the node
+ *
+ * Returns the nth parent of a node. If @depth is 0, the functionality is
+ * equivalent to fwnode_handle_get(). For @depth == 1, it is fwnode_get_parent()
+ * and so on.
+ *
+ * The caller is responsible for calling fwnode_handle_put() for the returned
+ * node.
+ */
+struct fwnode_handle *fwnode_get_nth_parent(struct fwnode_handle *fwnode,
+					    unsigned int depth)
+{
+	unsigned int i;
+
+	fwnode_handle_get(fwnode);
+
+	for (i = 0; i < depth && fwnode; i++)
+		fwnode = fwnode_get_next_parent(fwnode);
+
+	return fwnode;
+}
+EXPORT_SYMBOL_GPL(fwnode_get_nth_parent);
+
 /**
  * fwnode_get_next_child_node - Return the next child node handle for a node
  * @fwnode: Firmware node to find the next child node for.
diff --git a/include/linux/property.h b/include/linux/property.h
index 421c76e53708d..5450e7ec219ac 100644
--- a/include/linux/property.h
+++ b/include/linux/property.h
@@ -83,6 +83,9 @@ struct fwnode_handle *fwnode_find_reference(const struct fwnode_handle *fwnode,
 struct fwnode_handle *fwnode_get_parent(const struct fwnode_handle *fwnode);
 struct fwnode_handle *fwnode_get_next_parent(
 	struct fwnode_handle *fwnode);
+unsigned int fwnode_count_parents(const struct fwnode_handle *fwn);
+struct fwnode_handle *fwnode_get_nth_parent(struct fwnode_handle *fwn,
+					    unsigned int depth);
 struct fwnode_handle *fwnode_get_next_child_node(
 	const struct fwnode_handle *fwnode, struct fwnode_handle *child);
 struct fwnode_handle *fwnode_get_next_available_child_node(
-- 
2.20.1


  parent reply index

Thread overview: 36+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-09-02  8:32 [PATCH v4 00/11] Device property improvements, add %pfw format specifier Sakari Ailus
2019-09-02  8:32 ` [PATCH v4 01/11] software node: Get reference to parent swnode in get_parent op Sakari Ailus
2019-09-02 10:10   ` Andy Shevchenko
2019-09-02  8:32 ` [PATCH v4 02/11] software node: Make argument to to_software_node const Sakari Ailus
2019-09-02  8:32 ` [PATCH v4 03/11] device property: Move fwnode_get_parent() up Sakari Ailus
2019-09-02 10:11   ` Andy Shevchenko
2019-09-02  8:32 ` Sakari Ailus [this message]
2019-09-02 10:14   ` [PATCH v4 04/11] device property: Add functions for accessing node's parents Andy Shevchenko
2019-09-02 12:34     ` Sakari Ailus
2019-09-02 12:46       ` Andy Shevchenko
2019-09-02  8:32 ` [PATCH v4 05/11] device property: Add fwnode_get_name for returning the name of a node Sakari Ailus
2019-09-02  8:32 ` [PATCH v4 06/11] device property: Add a function to obtain a node's prefix Sakari Ailus
2019-09-02 10:16   ` Andy Shevchenko
2019-09-02  8:32 ` [PATCH v4 07/11] lib/vsprintf: Remove support for %pF and %pf in favour of %pS and %ps Sakari Ailus
2019-09-02 14:39   ` Petr Mladek
2019-09-02 16:01     ` Andy Shevchenko
2019-09-03 14:04       ` Petr Mladek
2019-09-06  6:59         ` Sakari Ailus
2019-09-02  8:32 ` [PATCH v4 08/11] lib/vsprintf: Make use of fwnode API to obtain node names and separators Sakari Ailus
2019-09-02 15:18   ` Petr Mladek
2019-09-02 15:41     ` Sakari Ailus
2019-09-02  8:32 ` [PATCH v4 09/11] lib/vsprintf: OF nodes are first and foremost, struct device_nodes Sakari Ailus
2019-09-02 10:21   ` Andy Shevchenko
2019-09-02  8:32 ` [PATCH v4 10/11] lib/vsprintf: Add %pfw conversion specifier for printing fwnode names Sakari Ailus
2019-09-03 13:06   ` Petr Mladek
2019-09-04 15:04     ` Sakari Ailus
2019-09-04 15:17       ` Andy Shevchenko
2019-09-04 15:39         ` Joe Perches
2019-09-04 15:54           ` Andy Shevchenko
2019-09-04 15:37       ` Joe Perches
2019-09-04 16:09         ` Sakari Ailus
2019-09-02  8:32 ` [PATCH v4 11/11] lib/test_printf: Add tests for %pfw printk modifier Sakari Ailus
2019-09-02 12:26   ` Andy Shevchenko
2019-09-02 13:09     ` Sakari Ailus
2019-09-03 13:38   ` Petr Mladek
2019-09-04 14:03     ` Sakari Ailus

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