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

PATCH In review Brian Norris 1 participant 3 messages Oct 28, 2015 – Oct 31, 2015 1 message not in the archive

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PATCH v4 1/1 doc: dt: mtd: support partitions in a special 'partitions' subnode

From: Michal Suchanek <[email protected]>

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.

---
 .../devicetree/bindings/mtd/partition.txt          | 71 +++++++++++++---------
 1 file changed, 42 insertions(+), 29 deletions(-)
Documentation/devicetree/bindings/mtd/partition.txt +42 -29
index 8e5557da1955..f1e2a02381a4 100644
@@ -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>;
+		};
 	};
 };
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#2 lore raw
Quoted 10 lines · Brian Norris

From: Michal Suchanek <[email protected]>

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.

---

Ugh, I wrote this up to stick below the '---' but I forgot to send it out with the patch. Here goes:

This is a resend with only slight modifications of Michal's v3 patch, for clarity:

http://thread.gmane.org/gmane.linux.drivers.mtd/60890/focus=60889

It's been reviewed by me and Rob and I plan to take it for v4.4. But at Rob's suggestion, I'm sending this to the devicetree-spec list too, as this is a binding for somewhat generic infrastructure, rather than just drivers.

Regards,
Brian

Quoted 108 lines
 .../devicetree/bindings/mtd/partition.txt          | 71 +++++++++++++---------
 1 file changed, 42 insertions(+), 29 deletions(-)
Documentation/devicetree/bindings/mtd/partition.txt +42 -29
index 8e5557da1955..f1e2a02381a4 100644
@@ -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>;
+		};
 	};
 };
Signature · 1 line
2.6.0.rc2.230.g3dd15c0