[PATCH v5 1/3] dt-bindings: mtd: partitions: Support label only partition

From: Ansuel Smith <ansuelsmth@gmail.com>
To: "Miquel Raynal" <miquel.raynal@bootlin.com>,
	"Richard Weinberger" <richard@nod.at>,
	"Vignesh Raghavendra" <vigneshr@ti.com>,
	"Rob Herring" <robh+dt@kernel.org>,
	"Krzysztof Kozlowski" <krzysztof.kozlowski+dt@linaro.org>,
	"Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
	"Jens Axboe" <axboe@kernel.dk>,
	"Ansuel Smith" <ansuelsmth@gmail.com>, �ecki <rafal@milecki.pl>,
	"Manivannan Sadhasivam" <mani@kernel.org>,
	linux-mtd@lists.infradead.org, devicetree@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: [PATCH v5 1/3] dt-bindings: mtd: partitions: Support label only partition
Date: Mon,  6 Jun 2022 17:14:15 +0200	[thread overview]
Message-ID: <20220606151417.19227-2-ansuelsmth@gmail.com> (raw)
In-Reply-To: <20220606151417.19227-1-ansuelsmth@gmail.com>

Document new partition nodes that declare only the label instead of the
reg used to provide an OF node for partition registred at runtime by
parsers. This is required for nvmem system to declare and detect
nvmem-cells.

With these special partitions, the reg / offset is not required.
The label binding is used to match the partition allocated by the
parser at runtime and the parser will provide reg and offset of the mtd.

NVMEM will use the data from the parser and provide the NVMEM cells
declared in the DTS, "connecting" the dynamic partition with a
static declaration of cells in them.

Signed-off-by: Ansuel Smith <ansuelsmth@gmail.com>
---
 .../bindings/mtd/partitions/partition.yaml       | 16 ++++++++++++++--
 1 file changed, 14 insertions(+), 2 deletions(-)

diff --git a/Documentation/devicetree/bindings/mtd/partitions/partition.yaml b/Documentation/devicetree/bindings/mtd/partitions/partition.yaml
index e1ac08064425..bff6fb980e6b 100644
--- a/Documentation/devicetree/bindings/mtd/partitions/partition.yaml
+++ b/Documentation/devicetree/bindings/mtd/partitions/partition.yaml
@@ -11,6 +11,13 @@ description: |
   relative offset and size specified. Depending on partition function extra
   properties can be used.
 
+  A partition may be dynamically allocated by a specific parser at runtime.
+  In this specific case, the label is required instead of the reg.
+  This is used to assign an OF node to the dynamiccally allocated partition
+  so that subsystem like NVMEM can provide an OF node and declare NVMEM cells.
+  The OF node will be assigned only if the partition label declared match the
+  one assigned by the parser at runtime.
+
 maintainers:
   - Rafał Miłecki <rafal@milecki.pl>
 
@@ -22,6 +29,8 @@ properties:
   label:
     description: The label / name for this partition. If omitted, the label
       is taken from the node name (excluding the unit address).
+      With dynamically allocated partition the label is required and won't
+      fallback to the node name.
 
   read-only:
     description: This parameter, if present, is a hint that this partition
@@ -41,7 +50,10 @@ properties:
       immune to paired-pages corruptions
     type: boolean
 
-required:
-  - reg
+if:
+  not:
+    required: [ reg ]
+then:
+  required: [ label ]
 
 additionalProperties: true
-- 
2.36.1

