The modern NAND controller binding requires NAND chips to be described as
child nodes of the controller, for example:
nand-controller {
...
nand@0 {
/* raw NAND chip properties */
};
};
However, many existing device trees place NAND chip properties directly
within the controller node because those controllers support only a single
chip. This layout is still widely used by older platforms and by other DT
consumers such as U-Boot. Migrating all existing users to the new layout
will take time.
Several kernel drivers, such as ams-delta.c, davinci_nand.c and
fsmc_nand.c, still expect the legacy layout where raw NAND properties are
defined in the controller node.
To support both layouts during the transition:
- Extract NAND chip-related properties into separate schemas
(nand-property.yaml and raw-nand-property.yaml) from
nand-chip.yaml and raw-nand-chip.yaml.
- Introduce nand-controller-legacy.yaml to allow both the
legacy and modern layouts.
- Add a select condition in nand-controller.yaml to prevent
node name pattern matching for fsl,* NAND controllers.
Keep compatibility with existing device trees while allowing gradual
migration to the modern binding structure.
Signed-off-by: Frank Li <Frank.Li@nxp.com>
Reviewed-by: Rob Herring (Arm) <robh@kernel.org>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
In an effort to constrain as much as we can the existing binding, we
want to add "unevaluatedProperties: false" in all the NAND chip
descriptions part of NAND controller bindings. But in order to do that
properly, we also need to reference a file which contains all the
"allowed" properties. Right now this file is nand-chip.yaml but in
practice raw NAND controllers may use additional properties in their
NAND chip children node. These properties are listed under
nand-controller.yaml, which makes the "unevaluatedProperties" checks
fail while the description are valid. We need to move these NAND chip
related properties into another file, because we do not want to pollute
nand-chip.yaml which is also referenced by eg. SPI-NAND devices.
Let's create a raw-nand-chip.yaml file to reference all the properties a
raw NAND chip description can contain. The chain of inheritance becomes:
nand-controller.yaml <- raw-nand-chip.yaml
raw-nand-chip.yaml <- nand-chip.yaml
spi-nand.yaml <- nand-chip.yaml
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/linux-mtd/20230619092916.3028470-3-miquel.raynal@bootlin.com
