From e571c885653830bc643e27f1e920018a1241d6e6 Mon Sep 17 00:00:00 2001
From: Peter Bigot <peter.bigot@nordicsemi.no>
Date: Sat, 31 Oct 2020 15:43:34 -0500
Subject: [PATCH] devicetree: flash-partitions: expose helper macros

Make generally available the macro that provides the flash device in
which a particular partition can be found.

Signed-off-by: Peter Bigot <peter.bigot@nordicsemi.no>
---
 include/devicetree.h                         | 21 ++++++++++++++++++++
 include/devicetree/fixed-partitions.h        | 11 ++++++++++
 subsys/storage/flash_map/flash_map_default.c | 17 ++++------------
 3 files changed, 36 insertions(+), 13 deletions(-)

diff --git a/include/devicetree.h b/include/devicetree.h
index 75574202ec3..87943d9a443 100644
--- a/include/devicetree.h
+++ b/include/devicetree.h
@@ -317,6 +317,27 @@
  */
 #define DT_PARENT(node_id) UTIL_CAT(node_id, _PARENT)
 
+/**
+ * @brief Get a node identifier for a grandparent node
+ *
+ * Example devicetree fragment:
+ *
+ *     gparent: grandparent-node {
+ *             parent: parent-node {
+ *                     child: child-node { ... }
+ *             };
+ *     };
+ *
+ * The following are equivalent ways to get the same node identifier:
+ *
+ *     DT_GPARENT(DT_NODELABEL(child))
+ *     DT_PARENT(DT_PARENT(DT_NODELABEL(child))
+ *
+ * @param node_id node identifier
+ * @return a node identifier for the node's parent's parent
+ */
+#define DT_GPARENT(node_id) DT_PARENT(DT_PARENT(node_id))
+
 /**
  * @brief Get a node identifier for a child node
  *
diff --git a/include/devicetree/fixed-partitions.h b/include/devicetree/fixed-partitions.h
index 0c1370fae74..4eeb31055c5 100644
--- a/include/devicetree/fixed-partitions.h
+++ b/include/devicetree/fixed-partitions.h
@@ -68,6 +68,17 @@ extern "C" {
  */
 #define DT_FIXED_PARTITION_ID(node_id) DT_CAT(node_id, _PARTITION_ID)
 
+/**
+ * @brief Get the node identifier of the flash device for a partition
+ * @param node_id node identifier for a fixed-partitions child node
+ * @return the node identifier of the memory technology device that
+ * contains the fixed-partitions node.
+ */
+#define DT_MTD_FROM_FIXED_PARTITION(node_id)				\
+	COND_CODE_1(DT_NODE_HAS_COMPAT(DT_GPARENT(node_id), soc_nv_flash), \
+		    (DT_PARENT(DT_GPARENT(node_id))),			\
+		    (DT_GPARENT(node_id)))
+
 /**
  * @}
  */
diff --git a/subsys/storage/flash_map/flash_map_default.c b/subsys/storage/flash_map/flash_map_default.c
index f627d6c5c4b..4f2830571af 100644
--- a/subsys/storage/flash_map/flash_map_default.c
+++ b/subsys/storage/flash_map/flash_map_default.c
@@ -10,19 +10,10 @@
 #include <zephyr.h>
 #include <storage/flash_map.h>
 
-/* Get the grand parent of a node */
-#define GPARENT(node_id) DT_PARENT(DT_PARENT(node_id))
-
-/* return great-grandparent label if 'soc-nv-flash' else grandparent label */
-#define DT_FLASH_DEV_FROM_PARTITION(part)				      \
-	DT_LABEL(COND_CODE_1(DT_NODE_HAS_COMPAT(GPARENT(part), soc_nv_flash), \
-			     (DT_PARENT(GPARENT(part))),		      \
-			     (GPARENT(part))))
-
-#define FLASH_AREA_FOO(part)					\
-	{.fa_id = DT_FIXED_PARTITION_ID(part),			\
-	 .fa_off = DT_REG_ADDR(part),				\
-	 .fa_dev_name = DT_FLASH_DEV_FROM_PARTITION(part),	\
+#define FLASH_AREA_FOO(part)						\
+	{.fa_id = DT_FIXED_PARTITION_ID(part),				\
+	 .fa_off = DT_REG_ADDR(part),					\
+	 .fa_dev_name = DT_LABEL(DT_MTD_FROM_FIXED_PARTITION(part)),	\
 	 .fa_size = DT_REG_SIZE(part),},
 
 #define FOREACH_PARTITION(n) DT_FOREACH_CHILD(DT_DRV_INST(n), FLASH_AREA_FOO)