[nrf fromlist] flash_map: Add a macro to fetch controller ID

Add a macro that allows to get the node identifier of the flash
controller the area/partition resides on.

Upstream PR #: 99800

Signed-off-by: Tomasz Chyrowicz <[email protected]>

Author: tomchy

include/zephyr/storage/flash_map.h

@@ -469,6 +469,31 @@ uint8_t flash_area_erased_val(const struct flash_area *fa);
 			(DT_MTD_FROM_FIXED_SUBPARTITION(node)), \
 			(DT_MTD_FROM_FIXED_PARTITION(node))))
 
+/**
+ * Get the node identifier of the flash controller the area/partition resides on
+ *
+ * @param label DTS node label of a partition
+ *
+ * @return Pointer to a device.
+ */
+#define FIXED_PARTITION_MTD(label) \
+	COND_CODE_1( \
+		DT_FIXED_SUBPARTITION_EXISTS(DT_NODELABEL(label)), \
+			(DT_MTD_FROM_FIXED_SUBPARTITION(DT_NODELABEL(label))), \
+			(DT_MTD_FROM_FIXED_PARTITION(DT_NODELABEL(label))))
+/**
+ * Get the node identifier of the flash controller the area/partition resides on
+ *
+ * @param node DTS node of a partition
+ *
+ * @return Pointer to a device.
+ */
+#define FIXED_PARTITION_NODE_MTD(node) \
+	COND_CODE_1( \
+		DT_FIXED_SUBPARTITION_EXISTS(node), \
+			(DT_MTD_FROM_FIXED_SUBPARTITION(node)), \
+			(DT_MTD_FROM_FIXED_PARTITION(node)))
+
 /**
  * Get pointer to flash_area object by partition label
  *