doc: dt: mtd: partitions: add compatible property to "partitions" node
authorBrian Norris <computersforpeace@gmail.com>
Thu, 3 Dec 2015 22:47:32 +0000 (14:47 -0800)
committerBrian Norris <computersforpeace@gmail.com>
Wed, 9 Dec 2015 01:10:20 +0000 (17:10 -0800)
commite488ca9f8d4f62c2dc36bfa5c32f68e7f05ab381
tree1679a478caabfbad8c177678afb4358d1130caad
parent8c62b4e118cfa7a3c906c01d4ba2c78a5bd97531
doc: dt: mtd: partitions: add compatible property to "partitions" node

As noted here [1], there are potentially future conflicts if we try to
use MTD's "partitions" subnode to describe anything besides just the
fixed-in-the-device-tree partitions currently described in this
document. Particularly, there was a proposal to use this node for the
AFS parser too.

It can pose a (small) problem to try to differentiate the following
nodes:

// using binding as currently specified
partitions {
#address-cells = <x>;
#size-cells = <y>;
partition@0 {
...;
};
};

and

// proposed future binding
partitions {
compatible = "arm,arm-flash-structure";
};

It's especially difficult if other uses of this node start having
subnodes.

So, since the "partitions" node is new in v4.4, let's fixup the binding
before release so that it requires a compatible property, so it's much
clearer to distinguish. e.g.:

// proposed
partitions {
compatible = "fixed-partitions";
#address-cells = <x>;
#size-cells = <y>;
partition@0 {
...;
};
};

[1] Subject: "mtd: create a partition type device tree binding"
    http://lkml.kernel.org/g/20151113220039.GA74382@google.com
    http://lists.infradead.org/pipermail/linux-mtd/2015-November/063355.html
    http://lists.infradead.org/pipermail/linux-mtd/2015-November/063364.html

Cc: Michal Suchanek <hramrach@gmail.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Acked-by: Rob Herring <robh@kernel.org>
Documentation/devicetree/bindings/mtd/partition.txt
drivers/mtd/ofpart.c