Re: [PATCH v22 4/8] dt-bindings: soc: nuvoton: add binding for clock and reset registers

[Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>]

On 16/01/2024 20:02, Tomer Maimon wrote:
> Hi Krzysztof,
> 
> Thanks for your comments.
> 
> Sorry for the long explanation but I think it is necessary.
> 
> In the NPCM8XX SoC, the reset and the clock register modules are
> scrambled in the same memory register region.
> The NPCM8XX Clock driver is still in the upstream process (for a long
> time) but the NPCM8XX reset driver is already upstreamed.
> 
> One of the main comments in the NPCM8XX Clock driver upstream process
> is that the clock register is mixed with the reset register and
> therefore we can't map (ioremap) the clock register
> region because is already mapped by the reset module, therefore we
> decided to use an external syscon to handle the clock and the reset
> registers driver.
> 
>  I highly appreciate your guidance on this topic.

Linux deals with it easily, that's why we have regmaps. What's the
problem exactly?

> 
> On Wed, 10 Jan 2024 at 22:59, Krzysztof Kozlowski
> <krzysztof.kozlowski@linaro.org> wrote:
>>
>> On 08/01/2024 14:54, Tomer Maimon wrote:
>>> A nuvoton,*-clk-rst node is present in nuvoton-common-npcm7xx.dtsi and
>>> will be added to nuvoton-common-npcm8xx.dtsi. It is necessary for the
>>> NPCM7xx and NPCM8xx clock and reset drivers, and may later be used to
>>> retrieve SoC model and version information.
>>>
>>
>> A nit, subject: drop second/last, redundant "bindings". The
>> "dt-bindings" prefix is already stating that these are bindings.
>> See also:
>> https://elixir.bootlin.com/linux/v6.7-rc8/source/Documentation/devicetree/bindings/submitting-patches.rst#L18
>>
>>> This patch adds a binding to describe this node.
>>
>> Please do not use "This commit/patch/change", but imperative mood. See
>> longer explanation here:
>> https://elixir.bootlin.com/linux/v5.17.1/source/Documentation/process/submitting-patches.rst#L95
>>
>>>
>>> Signed-off-by: Tomer Maimon <tmaimon77@gmail.com>
>>> ---
>>
>> How possibly could it be v22 if there is:
>> 1. No changelog
>> 2. No previous submissions
>> ?
> Should the dt-binding and dts patches be a part of the clock patch set
> (this is why it's V22) or should I open a new patch set?

You should explain what is happening here. That's why you have changelog
for.

>>
>> NAK, it's something completely new without any explanation.
>>
>> Limited review follows.
>>
>>
>>>  .../soc/nuvoton/nuvoton,npcm-clk-rst.yaml     | 40 +++++++++++++++++++
>>>  1 file changed, 40 insertions(+)
>>>  create mode 100644 Documentation/devicetree/bindings/soc/nuvoton/nuvoton,npcm-clk-rst.yaml
>>>
>>> diff --git a/Documentation/devicetree/bindings/soc/nuvoton/nuvoton,npcm-clk-rst.yaml b/Documentation/devicetree/bindings/soc/nuvoton/nuvoton,npcm-clk-rst.yaml
>>> new file mode 100644
>>> index 000000000000..dfec64a8eb26
>>> --- /dev/null
>>> +++ b/Documentation/devicetree/bindings/soc/nuvoton/nuvoton,npcm-clk-rst.yaml
>>> @@ -0,0 +1,40 @@
>>> +# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
>>> +%YAML 1.2
>>> +---
>>> +$id: http://devicetree.org/schemas/soc/nuvoton/nuvoton,npcm-clk-rst.yaml#
>>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
>>> +
>>> +title: Clock and reset registers block in Nuvoton SoCs
>>
>> This is vague. Any block? All blocks? Your SoC has only one block? I
>> doubt, although possible.
>>
>> Anyway, clocks go to clock directory, not to soc! We've been here and
>> you already received that feedback.
> Since one region handles the reset and the clock registers shouldn't I
> add the dt-binding to the SoC like the GCR and not to the clock

No, soc is not a dumping ground..

> directory?
> https://elixir.bootlin.com/linux/v6.7/source/Documentation/devicetree/bindings/soc/nuvoton/nuvoton,npcm-gcr.yaml

Choose the main feature of the block - either clock controller or reset
controller - and put it there.

>>
>>
>>> +
>>> +maintainers:
>>> +  - Tomer Maimon <tmaimon77@gmail.com>
>>> +
>>> +description:
>>> +  The clock and reset registers are a registers block in Nuvoton SoCs that
>>> +  handle both reset and clock functionality.
>>
>> That's still vague. Say something useful.
> Will describe more
>>
>>> +
>>> +properties:
>>> +  compatible:
>>> +    items:
>>> +      - enum:
>>> +          - nuvoton,npcm750-clk-rst
>>> +          - nuvoton,npcm845-clk-rst
>>> +      - const: syscon
>>> +      - const: simple-mfd
>>
>> No, it's not a syscon and not a simple-mfd. You just said it is clock
> Yes, I understand the syscon node represents a register region
> containing a set of miscellaneous registers, but as explain above it
> is quite the case here.

Nothing in this patch was telling this.

> I will remove the simple-mfd.
>> provider and reset controller. Thus missing clock cells and reset cells.
> The reset cell and clock cell found at the clock and reset dt-binding,
> is it enough?

This is the reset and clock binding, isn't it? You called it (your title):
"Clock and reset registers block in Nuvoton SoCs"




Best regards,
Krzysztof