Re: [PATCH v4 09/11] regulator: dt-bindings: Add Renesas RAA215300 PMIC bindings

From: Conor Dooley <conor.dooley@microchip.com>
To: Biju Das <biju.das.jz@bp.renesas.com>
Cc: Conor Dooley <conor@kernel.org>, Rob Herring <robh+dt@kernel.org>,
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
	Conor Dooley <conor+dt@kernel.org>,
	Liam Girdwood <lgirdwood@gmail.com>,
	Mark Brown <broonie@kernel.org>,
	Geert Uytterhoeven <geert+renesas@glider.be>,
	Magnus Damm <magnus.damm@gmail.com>,
	"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
	"linux-renesas-soc@vger.kernel.org" 
	<linux-renesas-soc@vger.kernel.org>,
	Fabrizio Castro <fabrizio.castro.jz@renesas.com>
Subject: Re: [PATCH v4 09/11] regulator: dt-bindings: Add Renesas RAA215300 PMIC bindings
Date: Fri, 19 May 2023 15:10:25 +0100	[thread overview]
Message-ID: <20230519-civic-idiocy-5ac6d95675f0@wendy> (raw)
In-Reply-To: <OS0PR01MB59226BDCD4D67430EC7377C6867C9@OS0PR01MB5922.jpnprd01.prod.outlook.com>

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On Fri, May 19, 2023 at 06:53:03AM +0000, Biju Das wrote:
> > Subject: Re: [PATCH v4 09/11] regulator: dt-bindings: Add Renesas
> > RAA215300 PMIC bindings
> > 
> > On Thu, May 18, 2023 at 12:36:41PM +0100, Biju Das wrote:
> > > Document Renesas RAA215300 PMIC bindings.
> > >
> > > The RAA215300 is a high Performance 9-Channel PMIC supporting DDR
> > > Memory, with Built-In Charger and RTC.
> > >
> > > It supports DDR3, DDR3L, DDR4, and LPDDR4 memory power requirements.
> > > The internally compensated regulators, built-in Real-Time Clock (RTC),
> > > 32kHz crystal oscillator, and coin cell battery charger provide a
> > > highly integrated, small footprint power solution ideal for
> > > System-On-Module (SOM) applications. A spread spectrum feature
> > > provides an ease-of-use solution for noise-sensitive audio or RF
> > > applications.
> > > +  reg:
> > > +    maxItems: 2
> > > +
> > > +  reg-names:
> > > +    items:
> > > +      - const: main
> > > +      - const: rtc
> > 
> > > +required:
> > > +  - compatible
> > > +  - reg
> > > +  - reg-names
> > 
> > Out of curiosity as much as anything else, why do you need reg-names if
> > the two registers are always required?
> 
> The device has always 2 address spaces and "reg-names" provides a means
> of clear differentiation compared to indices. 
> 
> By enforcing "reg-names" as required property, dt can do some schema-validation
> forcing users to specify "reg-names" in device tree.

Is that not what we have the following for:
  reg:
   items:
     - description: main register space...
     - description: special sauce rtc stuff...
?

The schema validation doesn't stop them putting in the wrong address
either way!

> Implementation wise, we use "rtc" for getting resource details while
> creating the second i2c device which overrides the default address.
> 
> Strictly speaking reg-names is not required, but from a validation
> perspective and since driver is using the same "resource-name" it is
> better to have it??

If the order is set by the descriptions, reg-names seem superfluous
/shrug

Cheers,
Conor.

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