[PATCH v2] mtd: nand: document the NAND controller/NAND chip DT representation

Boris Brezillon
2016-04-01T12:27:04Z

Standardize the NAND controller/NAND chip DT representation. Now, all new
NAND controller drivers should comply with this representation, even if
they are only supporting a single NAND chip.

Existing drivers can keep support for the old representation (where only
the NAND chip was described), but are encouraged to also support the new
one.

Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
---
Changes since v1:
- fix typo
---
Documentation/devicetree/bindings/mtd/nand.txt | 37 +++++++++++++++++++++++++-
1 file changed, 36 insertions(+), 1 deletion(-)

diff --git a/Documentation/devicetree/bindings/mtd/nand.txt b/Documentation/devicetree/bindings/mtd/nand.txt
index b53f92e..a17662b 100644
--- a/Documentation/devicetree/bindings/mtd/nand.txt
+++ b/Documentation/devicetree/bindings/mtd/nand.txt
@@ -1,4 +1,23 @@
-* MTD generic binding
+* NAND chip and NAND controller generic binding
+
+NAND controller/NAND chip representation:
+
+The NAND controller should be represented with its own DT node, and all
+NAND chips attached to this controller should be defined as children nodes
+of the NAND controller. This representation should be enforced even for
+simple controllers supporting only one chip.
+
+Mandatory NAND controller properties:
+- #address-cells: depends on your controller. Should at least be 1 to
+ encode the CS line id.
+- #size-cells: depends on your controller. Put zero unless you need a
+ mapping between CS lines and dedicated memory regions
+
+Optional NAND controller properties
+- ranges: only needed if you need to define a mapping between CS lines and
+ memory regions
+
+Optional NAND chip properties:

- nand-ecc-mode : String, operation mode of the NAND ecc mode.
Supported values are: "none", "soft", "hw", "hw_syndrome", "hw_oob_first",
@@ -19,3 +38,19 @@ errors per {size} bytes".
The interpretation of these parameters is implementation-defined, so not all
implementations must support all possible combinations. However, implementations
are encouraged to further specify the value(s) they support.
+
+Example:
+
+ nand-controller {
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ /* controller specific properties */
+
+ nand@0 {
+ reg = <0>;
+ nand-ecc-mode = "soft_bch";
+
+ /* controller specific properties */
+ };
+ };
--
2.5.0