On Mon, Sep 20, 2021 at 06:06:51PM +0300, Serge Semin wrote:

Hello Apurva

On Mon, Sep 20, 2021 at 07:57:12PM +0530, Apurva Nandan wrote:

quoted

Convert spi-nand.txt binding to YAML format with an added example.

Signed-off-by: Apurva Nandan <redacted>
---
 .../devicetree/bindings/mtd/spi-nand.txt      |  5 --
 .../devicetree/bindings/mtd/spi-nand.yaml     | 62 +++++++++++++++++++
 2 files changed, 62 insertions(+), 5 deletions(-)
 delete mode 100644 Documentation/devicetree/bindings/mtd/spi-nand.txt
 create mode 100644 Documentation/devicetree/bindings/mtd/spi-nand.yaml

Thanks for the bindings conversion patch. There are several comments
below. But before addressing them it would be better to also get a
response from Rob.

quoted

diff --git a/Documentation/devicetree/bindings/mtd/spi-nand.txt b/Documentation/devicetree/bindings/mtd/spi-nand.txt
deleted file mode 100644
index 8b51f3b6d55c..000000000000
--- a/Documentation/devicetree/bindings/mtd/spi-nand.txt
+++ /dev/null

@@ -1,5 +0,0 @@
-SPI NAND flash
-
-Required properties:
-- compatible: should be "spi-nand"
-- reg: should encode the chip-select line used to access the NAND chip

diff --git a/Documentation/devicetree/bindings/mtd/spi-nand.yaml b/Documentation/devicetree/bindings/mtd/spi-nand.yaml
new file mode 100644
index 000000000000..601beba8d971
--- /dev/null
+++ b/Documentation/devicetree/bindings/mtd/spi-nand.yaml

@@ -0,0 +1,62 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/mtd/spi-nand.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: SPI NAND flash
+
+maintainers:
+  - Apurva Nandan <a-nandan@ti.com>
+
+allOf:
+  - $ref: "mtd.yaml#"
+
+properties:
+  compatible:
+    const: spi-nand
+
+  reg:
+    maxItems: 1
+

quoted

+  spi-max-frequency: true
+  spi-rx-bus-width: true
+  spi-tx-bus-width: true
+  rx-sample-delay-ns: true

Since it's an SPI-client device there are more than these properties
could be set for it. See the SPI-controller bindings schema:
Documentation/devicetree/bindings/spi/spi-controller.yaml
So there is two possible ways to make it more generic:
1) Detach the spi-client part from the spi-controller.yaml bindings
into a dedicated DT-schema file and refer to that new scheme from
here.

Yes, as mentioned there's patches doing this. But the above is fine. 
There's some value in defining here which properties are valid.

2) Forget about these controller-specific properties and let the
parental SPI-controller bindings parsing them. Of course there must be
at least one of the next properties declared for it to work:
{unevaluatedProperties, additionalProperties}.

It's up to Rob to decided which approach is better though...

quoted

+
+  '#address-cells': true
+  '#size-cells': true

Aren't they always equal to 1?

No SPI nand devices >4GB?

quoted

+
+additionalProperties:
+  type: object

I'd suggest to elaborate the way the partition sub-nodes looks
like, for instance, the node names, supported compatible names,
labels, etc.

That should probably all be in mtd.yaml. The question here is whether 
partitions are always under a 'partitions' node. Maybe this is new 
enough that only the new way has to be supported. Though if mtd.yaml 
supported both forms, allowing both all the time is okay IMO.

Rob