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Date:   Fri, 8 Jul 2022 18:05:28 +0200
From:   Pali =?utf-8?B?Um9ow6Fy?= <pali@kernel.org>
To:     Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Cc:     Marek =?utf-8?B?QmVow7pu?= <kabel@kernel.org>,
        Pavel Machek <pavel@ucw.cz>, Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        linux-leds@vger.kernel.org, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 1/2] [RFT] dt-bindings: leds: Add
 cznic,turris1x-leds.yaml binding
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On Wednesday 06 July 2022 17:36:43 Krzysztof Kozlowski wrote:
> On 06/07/2022 17:27, Marek Behún wrote:
> > On Wed, 6 Jul 2022 13:19:12 +0200
> > Pali Rohár <pali@kernel.org> wrote:
> > 
> >> On Wednesday 06 July 2022 13:15:07 Marek Behún wrote:
> >>> On Tue,  5 Jul 2022 17:59:28 +0200
> >>> Pali Rohár <pali@kernel.org> wrote:
> >>>   
> >>>> +examples:
> >>>> +  - |
> >>>> +    #include <dt-bindings/leds/common.h>
> >>>> +
> >>>> +    cpld@3,0 {  
> >>>
> >>> The generic node name should be just "bus". That it is a CPLD
> >>> implementation should come from compatible string.  
> >>
> >> Sorry, I do not understand why "bus". Why other memory chips are named
> >> e.g. "nand" or "nor" and not "bus" too?
> > 
> > As far as I understand this is because that is the preferred name for
> > busses and this is a bus, since there is also the simple-bus compatible.
> > 
> >> By this logic should not be _every_ node called just "bus"? Hm... and 
> >> are names needed at all then?
> > 
> > :-)
> > 
> > The schema
> >   https://github.com/devicetree-org/dt-schema/blob/main/dtschema/schemas/simple-bus.yaml
> > allows for different names (soc|axi|ahb|*-bus) to avoid warnings on
> > existing old dts files.
> > 
> > The preferred way is to not have the implementation in nodename,
> > similar to how we use 'switch' instead of 'mv88e6xxx', or
> > 'ethernet-phy' instead of 'mv88e151x', or 'led-controller', ...
> 
> Thanks Marek for detailed explanation.
> The cases above rather trigger my comments and this one here, after
> Pali's explanation, do not fit them. pld is a generic class of a device,
> so it is okay here. cpld probably as well (although one could argue that
> it is a subset of pld, so the generic name is pld, but then one would
> say fpga also should be called pld). For me it does not have to be bus,
> just don't want mv88e6xxx or any other vendor/model names. Therefore
> cpld is fine.

Exactly. cpld, fpga, nor, nand, soc... all of them are not real buses.

simple-bus here is just name invented by device tree and without which
existing kernel drivers refuse to work.

> > 
> > I wasn't there when people started requesting for this to be that way,
> > but I guess it makes some sense to make it more readable and less
> > redundant (the generic name in nodename and the implementation in
> > compatible string...).
> 
> 
> 
> 
> Best regards,
> Krzysztof