[PATCH RFC 9/9] dt-bindings: nand: Convert fsl,elbc bindings to YAML
J. Neuschäfer
j.ne at posteo.net
Fri Feb 7 09:59:01 AEDT 2025
On Sun, Jan 26, 2025 at 10:23:21PM -0600, Rob Herring wrote:
> On Sun, Jan 26, 2025 at 07:59:04PM +0100, J. Neuschäfer wrote:
> > Convert the Freescale localbus controller bindings from text form to
> > YAML. The list of compatible strings reflects current usage.
> >
> > Changes compared to the txt version:
> > - removed the board-control (fsl,mpc8272ads-bcsr) node because it only
> > appears in this example and nowhere else
> > - added a new example with NAND flash
> >
> > Remaining issues:
> > - The localbus is not really a simple-bus: Unit addresses are not simply
> > addresses on a memory bus. Instead, they have a format: The first cell
> > is a chip select number, the remaining one or two cells are bus
> > addresses.
>
> That's every external parallel bus. See bindings/memory-controllers/*
>
> Probably fine to leave 'simple-bus' if that's your question. It's more
> that there is configuration for the chipselect timings that make's this
> not a simple-bus. But the address translation should work just fine.
My concern mainly stems from the resulting warnings if I allow/use simple-bus:
Documentation/devicetree/bindings/memory-controllers/fsl,elbc.example.dts:77.23-84.15:
Warning (simple_bus_reg): /example-1/localbus at e0005000/flash at 0,0: simple-bus unit address format error, expected "0"
Documentation/devicetree/bindings/memory-controllers/fsl,elbc.example.dts:86.22-92.15:
Warning (simple_bus_reg): /example-1/localbus at e0005000/nand at 1,0: simple-bus unit address format error, expected "100000000"
Existing devicetrees specify the eLBC with compatible = ..., "simple-bus",
which lead me to include the simple-bus compatible both in the binding
itself and in the examples, which in turn leads to (correct) warnings
from DTC about node names such as nand at 1,0 (it expects 100000000).
nand at 1,0 was however completely correct for the eLBC bus, because it's
not one big linear address, but rather a chip select (1) and an address (0).
My current idea to resolve this contradiction is to remove simple-bus
from the binding and change affected devicetrees later.
>
> >
> > Signed-off-by: J. Neuschäfer <j.ne at posteo.net>
> > ---
> > .../devicetree/bindings/mtd/fsl,elbc-fcm-nand.yaml | 61 +++++++++
> > .../bindings/powerpc/fsl/fsl,elbc-gpcm-uio.yaml | 55 ++++++++
> > .../devicetree/bindings/powerpc/fsl/fsl,elbc.yaml | 150 +++++++++++++++++++++
> > .../devicetree/bindings/powerpc/fsl/lbc.txt | 43 ------
> > 4 files changed, 266 insertions(+), 43 deletions(-)
> >
> > diff --git a/Documentation/devicetree/bindings/mtd/fsl,elbc-fcm-nand.yaml b/Documentation/devicetree/bindings/mtd/fsl,elbc-fcm-nand.yaml
> > new file mode 100644
> > index 0000000000000000000000000000000000000000..127f164443972bbaf50fd9daa80c504577ddd7bd
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/mtd/fsl,elbc-fcm-nand.yaml
> > @@ -0,0 +1,61 @@
> > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> > +%YAML 1.2
> > +---
> > +$id: http://devicetree.org/schemas/mtd/fsl,elbc-fcm-nand.yaml#
> > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > +
> > +title: NAND flash attached to Freescale eLBC
> > +
> > +maintainers:
> > + - J. Neuschäfer <j.ne at posteo.net>
> > +
> > +allOf:
> > + - $ref: nand-chip.yaml#
> > +
> > +properties:
> > + compatible:
> > + oneOf:
>
> Don't need oneOf.
How would I express "either one of various chip-specific strings
followed by fsl,elbc-fcm-nand, or fsl,elbc-fcm-nand alone"?
>
> > + - items:
> > + - enum:
> > + - fsl,mpc8313-fcm-nand
> > + - fsl,mpc8315-fcm-nand
> > + - fsl,mpc8377-fcm-nand
> > + - fsl,mpc8378-fcm-nand
> > + - fsl,mpc8379-fcm-nand
> > + - fsl,mpc8536-fcm-nand
> > + - fsl,mpc8569-fcm-nand
> > + - fsl,mpc8572-fcm-nand
> > + - fsl,p1020-fcm-nand
> > + - fsl,p1021-fcm-nand
> > + - fsl,p1025-fcm-nand
> > + - fsl,p2020-fcm-nand
> > + - const: fsl,elbc-fcm-nand
> > + - const: fsl,elbc-fcm-nand
> > +
> > + reg:
> > + maxItems: 1
> > +
> > + "#address-cells": true
> > +
> > + "#size-cells": true
> > +
> > +required:
> > + - compatible
> > + - reg
> > +
> > +additionalProperties: false
>
> If you use anything from nand-chip.yaml, then you need
> unevaluatedProperties here.
Noted, will fix.
>
> > +
> > +examples:
> > + - |
> > + localbus {
> > + #address-cells = <2>;
> > + #size-cells = <1>;
> > +
> > + nand at 1,0 {
> > + #address-cells = <1>;
> > + #size-cells = <1>;
> > + compatible = "fsl,mpc8315-fcm-nand",
> > + "fsl,elbc-fcm-nand";
> > + reg = <0x1 0x0 0x2000>;
> > + };
> > + };
> > diff --git a/Documentation/devicetree/bindings/powerpc/fsl/fsl,elbc-gpcm-uio.yaml b/Documentation/devicetree/bindings/powerpc/fsl/fsl,elbc-gpcm-uio.yaml
> > new file mode 100644
> > index 0000000000000000000000000000000000000000..60f849b79c11a4060f2fa4ab163f9fa9317df130
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/powerpc/fsl/fsl,elbc-gpcm-uio.yaml
> > @@ -0,0 +1,55 @@
> > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> > +%YAML 1.2
> > +---
> > +$id: http://devicetree.org/schemas/powerpc/fsl/fsl,elbc-gpcm-uio.yaml#
> > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > +
> > +title: Userspace I/O interface for Freescale eLBC devices
> > +
> > +maintainers:
> > + - J. Neuschäfer <j.ne at posteo.net>
> > +
> > +properties:
> > + compatible:
> > + const: fsl,elbc-gpcm-uio
> > +
> > + reg:
> > + maxItems: 1
> > +
> > + elbc-gpcm-br:
> > + description: Base Register (BR) value to set
> > + $ref: /schemas/types.yaml#/definitions/uint32
> > +
> > + elbc-gpcm-or:
> > + description: Option Register (OR) value to set
> > + $ref: /schemas/types.yaml#/definitions/uint32
> > +
> > + device_type: true
>
> This should be dropped.
Will do
> > diff --git a/Documentation/devicetree/bindings/powerpc/fsl/fsl,elbc.yaml b/Documentation/devicetree/bindings/powerpc/fsl/fsl,elbc.yaml
[...]
> > + "#address-cells":
> > + enum: [2, 3]
> > + description: |
>
> Don't need '|' unless there's some formatting.
Will remove.
>
> > + The first cell is the chipselect number, and the remaining cells are the
> > + offset into the chipselect.
> > +
> > + "#size-cells":
> > + enum: [1, 2]
> > + description: |
> > + Either one or two, depending on how large each chipselect can be.
> > +
> > + ranges:
> > + description: |
> > + Each range corresponds to a single chipselect, and covers the entire
> > + access window as configured.
> > +
> > +patternProperties:
> > + "^.*@.*$":
>
> You should define the unit-address format here: @<chipselect>,<offset>
Will do.
Thanks,
J. Neuschäfer
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