Re: [PATCH 1/3] dt-bindings: spi: Add realtek,rtl9300-snand

[Krzysztof Kozlowski <krzk@kernel.org>]

On 07/10/2024 21:58, Chris Packham wrote:
> 
> On 7/10/24 19:40, Krzysztof Kozlowski wrote:
>> On Mon, Oct 07, 2024 at 12:33:45PM +1300, Chris Packham wrote:
>>> Add a dtschema for the SPI-NAND controller on the RTL9300 SoCs. The
>>> controller supports
>>>   * Serial/Dual/Quad data with
>>>   * PIO and DMA data read/write operation
>>>   * Configurable flash access timing
>>>
>>> Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
>>> ---
>>>   .../bindings/spi/realtek,rtl9300-snand.yaml   | 58 +++++++++++++++++++
>>>   1 file changed, 58 insertions(+)
>>>   create mode 100644 Documentation/devicetree/bindings/spi/realtek,rtl9300-snand.yaml
>>>
>>> diff --git a/Documentation/devicetree/bindings/spi/realtek,rtl9300-snand.yaml b/Documentation/devicetree/bindings/spi/realtek,rtl9300-snand.yaml
>>> new file mode 100644
>>> index 000000000000..c66aea24cb35
>>> --- /dev/null
>>> +++ b/Documentation/devicetree/bindings/spi/realtek,rtl9300-snand.yaml
>>> @@ -0,0 +1,58 @@
>>> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
>>> +%YAML 1.2
>>> +---
>>> +$id: http://devicetree.org/schemas/spi/realtek,rtl9300-snand.yaml#
>>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
>>> +
>>> +title: SPI-NAND Flash Controller for Realtek RTL9300 SoCs
>>> +
>>> +maintainers:
>>> +  - Chris Packham <chris.packham@alliedtelesis.co.nz>
>>> +
>>> +description:
>>> +  The Realtek RTL9300 SoCs have a built in SPI-NAND controller. It supports
>>> +  typical SPI-NAND page cache operations in single, dual or quad IO mode.
>>> +
>>> +properties:
>>> +  compatible:
>>> +    items:
>> Why 9300 cannot be alone? What does 9300 mean even? Wildcards and family
>> models are not allowed in general.
> 
> The main thing about the RTL9300 is that that is what all the Realtek 
> documents use to refer to these chips and the specific numbers are akin 
> to the manufacturing part number that you'd actually order (maybe that's 
> a bit of a stretch).
> 
> The SoC/CPU block probably does exist as a separate silicon die that 
> they connect to the different switch blocks in the chips that they sell 
> but I don't think you can get "just" the SoC. There is every chance that 
> we'll see that same SoC/CPU block pop up in new chips (I see references 
> to a RTL9302D in some documents). I'd like to be able to support these 
> chips using "rtl9300" but if that's violating the wildcard rule I can 
> drop it.

Yeah, that's violating the wildcard rule. You cannot even guarantee that
9300 will match future designs.

> 
>>> +      - enum:
>>> +          - realtek,rtl9301-snand
>>> +          - realtek,rtl9302b-snand
>>> +          - realtek,rtl9302c-snand
>>> +          - realtek,rtl9303-snand
>>> +      - const: realtek,rtl9300-snand
>>> +
>>> +  reg:
>>> +    items:
>>> +      - description: SPI NAND controller registers address and size
>> Also: why no clocks? Binding is supposed to be complete. If it cannot,
>> you should explain it in the commit msg.
> 
> I didn't add it because I had no need for it in my driver. But as you've 
> said previously the binding shouldn't care what the driver does.
> 
> I do have the clocking info from the datasheets. I'll add it in v2.


Best regards,
Krzysztof