[PATCH] dt-bindings: mtd: spi-nor: clarify the need for spi-nor compatibles

[PATCH] dt-bindings: mtd: spi-nor: clarify the need for spi-nor compatibles

[Miquel Raynal]

Most SPI NOR devices do not require a specific compatible, their ID can
in general be discovered with the JEDEC READ ID opcode. In this case,
only the "jedec,spi-nor" generic compatible is expected. Clarify this
information in the compatible description to (i) help device-tree
writers and (ii) prevent further attempts to extend this list with
useless information.

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
---
 Documentation/devicetree/bindings/mtd/jedec,spi-nor.yaml | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/Documentation/devicetree/bindings/mtd/jedec,spi-nor.yaml b/Documentation/devicetree/bindings/mtd/jedec,spi-nor.yaml
index 7149784a36ac..bef071163e38 100644
--- a/Documentation/devicetree/bindings/mtd/jedec,spi-nor.yaml
+++ b/Documentation/devicetree/bindings/mtd/jedec,spi-nor.yaml
@@ -43,8 +43,10 @@ properties:
           - const: jedec,spi-nor
       - const: jedec,spi-nor
     description:
-      Must also include "jedec,spi-nor" for any SPI NOR flash that can be
-      identified by the JEDEC READ ID opcode (0x9F).
+      SPI NOR flashes compatible with the JEDEC standard or which may be
+      identified with the JEDEC READ ID opcode (0x9F) do not deserve a
+      specific compatible. They should instead only be matched against
+      the generic "jedec,spi-nor" compatible.
 
   reg:
     minItems: 1
-- 
2.34.1

Re: [PATCH] dt-bindings: mtd: spi-nor: clarify the need for spi-nor compatibles

[Krzysztof Kozlowski]

On 16/06/2023 16:00, Miquel Raynal wrote:
> Most SPI NOR devices do not require a specific compatible, their ID can
> in general be discovered with the JEDEC READ ID opcode. In this case,
> only the "jedec,spi-nor" generic compatible is expected. Clarify this
> information in the compatible description to (i) help device-tree
> writers and (ii) prevent further attempts to extend this list with
> useless information.
> 
> Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
> ---

Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>

Best regards,
Krzysztof

Re: [PATCH] dt-bindings: mtd: spi-nor: clarify the need for spi-nor compatibles

[Tudor Ambarus]

Hi, Miquel,

On 6/16/23 15:00, Miquel Raynal wrote:
> Most SPI NOR devices do not require a specific compatible, their ID can
> in general be discovered with the JEDEC READ ID opcode. In this case,
> only the "jedec,spi-nor" generic compatible is expected. Clarify this
> information in the compatible description to (i) help device-tree
> writers and (ii) prevent further attempts to extend this list with
> useless information.

Sounds good. If you don't mind I'll reword the description from below
when applying.

> 
> Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
> ---
>  Documentation/devicetree/bindings/mtd/jedec,spi-nor.yaml | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/mtd/jedec,spi-nor.yaml b/Documentation/devicetree/bindings/mtd/jedec,spi-nor.yaml
> index 7149784a36ac..bef071163e38 100644
> --- a/Documentation/devicetree/bindings/mtd/jedec,spi-nor.yaml
> +++ b/Documentation/devicetree/bindings/mtd/jedec,spi-nor.yaml
> @@ -43,8 +43,10 @@ properties:
>            - const: jedec,spi-nor
>        - const: jedec,spi-nor
>      description:
> -      Must also include "jedec,spi-nor" for any SPI NOR flash that can be
> -      identified by the JEDEC READ ID opcode (0x9F).
> +      SPI NOR flashes compatible with the JEDEC standard or which may be

s/JEDEC/JEDEC216, s/may/can

> +      identified with the JEDEC READ ID opcode (0x9F) do not deserve a

"deserve" is a little harsh. How about "must be matched against
the generic ...".

For future me: 0x9f is not a JEDEC216 opcode, it just happened
that the industry agreed on a specific opcode for reading the
ID of the flash. JEDEC216 doesn't care about the flash's ID.
We care because of the fixup hooks.

Cheers,
ta
> +      specific compatible. They should instead only be matched against
> +      the generic "jedec,spi-nor" compatible.
>  
>    reg:
>      minItems: 1

Re: [PATCH] dt-bindings: mtd: spi-nor: clarify the need for spi-nor compatibles

[Miquel Raynal]

Hi Tudor,

tudor.ambarus@linaro.org wrote on Fri, 30 Jun 2023 09:36:10 +0100:

> Hi, Miquel,
> 
> On 6/16/23 15:00, Miquel Raynal wrote:
> > Most SPI NOR devices do not require a specific compatible, their ID can
> > in general be discovered with the JEDEC READ ID opcode. In this case,
> > only the "jedec,spi-nor" generic compatible is expected. Clarify this
> > information in the compatible description to (i) help device-tree
> > writers and (ii) prevent further attempts to extend this list with
> > useless information.  
> 
> Sounds good. If you don't mind I'll reword the description from below
> when applying.

Of course. I think you're right to further specify the exact
specification name.

> 
> > 
> > Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
> > ---
> >  Documentation/devicetree/bindings/mtd/jedec,spi-nor.yaml | 6 ++++--
> >  1 file changed, 4 insertions(+), 2 deletions(-)
> > 
> > diff --git a/Documentation/devicetree/bindings/mtd/jedec,spi-nor.yaml b/Documentation/devicetree/bindings/mtd/jedec,spi-nor.yaml
> > index 7149784a36ac..bef071163e38 100644
> > --- a/Documentation/devicetree/bindings/mtd/jedec,spi-nor.yaml
> > +++ b/Documentation/devicetree/bindings/mtd/jedec,spi-nor.yaml
> > @@ -43,8 +43,10 @@ properties:
> >            - const: jedec,spi-nor
> >        - const: jedec,spi-nor
> >      description:
> > -      Must also include "jedec,spi-nor" for any SPI NOR flash that can be
> > -      identified by the JEDEC READ ID opcode (0x9F).
> > +      SPI NOR flashes compatible with the JEDEC standard or which may be  
> 
> s/JEDEC/JEDEC216, s/may/can
> 
> > +      identified with the JEDEC READ ID opcode (0x9F) do not deserve a  
> 
> "deserve" is a little harsh. How about "must be matched against
> the generic ...".
> 
> For future me: 0x9f is not a JEDEC216 opcode, it just happened
> that the industry agreed on a specific opcode for reading the
> ID of the flash. JEDEC216 doesn't care about the flash's ID.
> We care because of the fixup hooks.
> 
> Cheers,
> ta
> > +      specific compatible. They should instead only be matched against
> > +      the generic "jedec,spi-nor" compatible.
> >  
> >    reg:
> >      minItems: 1  


Thanks,
Miquèl

Re: [PATCH] dt-bindings: mtd: spi-nor: clarify the need for spi-nor compatibles

[Tudor Ambarus]

On Fri, 16 Jun 2023 16:00:54 +0200, Miquel Raynal wrote:
> Most SPI NOR devices do not require a specific compatible, their ID can
> in general be discovered with the JEDEC READ ID opcode. In this case,
> only the "jedec,spi-nor" generic compatible is expected. Clarify this
> information in the compatible description to (i) help device-tree
> writers and (ii) prevent further attempts to extend this list with
> useless information.
> 
> [...]

[ta: s/JEDEC/JEDEC SFDP for clarity and s/JEDEC READ ID/READ ID as
the opcode is not part of the JEDEC SFDP standard.]

Applied to git://git.kernel.org/pub/scm/linux/kernel/git/mtd/linux.git,
spi-nor/next branch. Thanks!

[1/1] dt-bindings: mtd: spi-nor: clarify the need for spi-nor compatibles
      https://git.kernel.org/mtd/c/4b0cb4e7ab2f

Cheers,
-- 
Tudor Ambarus <tudor.ambarus@linaro.org>