doc: dt: mtd: support partitions in a special 'partitions' subnode

To avoid conflict with other drivers using subnodes of the mtd device
create only one ofpart-specific node rather than any number of
arbitrary partition subnodes.

Signed-off-by: Michal Suchanek <hramrach@gmail.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

1 files changed, 42 insertions, 29 deletions

diff --git a/Documentation/devicetree/bindings/mtd/partition.txt b/Documentation/devicetree/bindings/mtd/partition.txt
index 8e5557da1955..f1e2a02381a4 100644
--- a/Documentation/devicetree/bindings/mtd/partition.txt
+++ b/Documentation/devicetree/bindings/mtd/partition.txt
@@ -4,10 +4,17 @@ Partitions can be represented by sub-nodes of an mtd device. This can be used
 on platforms which have strong conventions about which portions of a flash are
 used for what purposes, but which don't use an on-flash partition table such
 as RedBoot.
-NOTE: if the sub-node has a compatible string, then it is not a partition.
 
-#address-cells & #size-cells must both be present in the mtd device. There are
-two valid values for both:
+The partition table should be a subnode of the mtd node and should be named
+'partitions'. Partitions are defined in subnodes of the partitions node.
+
+For backwards compatibility partitions as direct subnodes of the mtd device are
+supported. This use is discouraged.
+NOTE: also for backwards compatibility, direct subnodes that have a compatible
+string are not considered partitions, as they may be used for other bindings.
+
+#address-cells & #size-cells must both be present in the partitions subnode of the
+mtd device. There are two valid values for both:
 <1>: for partitions that require a single 32-bit cell to represent their
      size/address (aka the value is below 4 GiB)
 <2>: for partitions that require two 32-bit cells to represent their
@@ -28,44 +35,50 @@ Examples:
 
 
 flash@0 {
-        #address-cells = <1>;
-        #size-cells = <1>;
+        partitions {
+                #address-cells = <1>;
+                #size-cells = <1>;
 
-        partition@0 {
-                label = "u-boot";
-                reg = <0x0000000 0x100000>;
-                read-only;
-        };
+                partition@0 {
+                        label = "u-boot";
+                        reg = <0x0000000 0x100000>;
+                        read-only;
+                };
 
-        uimage@100000 {
-                reg = <0x0100000 0x200000>;
+                uimage@100000 {
+                        reg = <0x0100000 0x200000>;
+                };
         };
 };
 
 flash@1 {
-        #address-cells = <1>;
-        #size-cells = <2>;
+        partitions {
+                #address-cells = <1>;
+                #size-cells = <2>;
 
-        /* a 4 GiB partition */
-        partition@0 {
-                label = "filesystem";
-                reg = <0x00000000 0x1 0x00000000>;
+                /* a 4 GiB partition */
+                partition@0 {
+                        label = "filesystem";
+                        reg = <0x00000000 0x1 0x00000000>;
+                };
         };
 };
 
 flash@2 {
-        #address-cells = <2>;
-        #size-cells = <2>;
+        partitions {
+                #address-cells = <2>;
+                #size-cells = <2>;
 
-        /* an 8 GiB partition */
-        partition@0 {
-                label = "filesystem #1";
-                reg = <0x0 0x00000000 0x2 0x00000000>;
-        };
+                /* an 8 GiB partition */
+                partition@0 {
+                        label = "filesystem #1";
+                        reg = <0x0 0x00000000 0x2 0x00000000>;
+                };
 
-        /* a 4 GiB partition */
-        partition@200000000 {
-                label = "filesystem #2";
-                reg = <0x2 0x00000000 0x1 0x00000000>;
+                /* a 4 GiB partition */
+                partition@200000000 {
+                        label = "filesystem #2";
+                        reg = <0x2 0x00000000 0x1 0x00000000>;
+                };
         };
 };