Re: [PATCH 02/13] dt-bindings: i2c: nomadik: add mobileye,eyeq5-i2c bindings and example

From: "Théo Lebrun" <theo.lebrun@bootlin.com>
To: "Rob Herring" <robh@kernel.org>
Cc: "Linus Walleij" <linus.walleij@linaro.org>,
	"Andi Shyti" <andi.shyti@kernel.org>,
	"Krzysztof Kozlowski" <krzysztof.kozlowski+dt@linaro.org>,
	"Conor Dooley" <conor+dt@kernel.org>,
	"Thomas Bogendoerfer" <tsbogend@alpha.franken.de>,
	<linux-arm-kernel@lists.infradead.org>,
	<linux-i2c@vger.kernel.org>, <devicetree@vger.kernel.org>,
	<linux-kernel@vger.kernel.org>, <linux-mips@vger.kernel.org>,
	"Gregory Clement" <gregory.clement@bootlin.com>,
	"Vladimir Kondratiev" <vladimir.kondratiev@mobileye.com>,
	"Thomas Petazzoni" <thomas.petazzoni@bootlin.com>,
	"Tawfik Bayouk" <tawfik.bayouk@mobileye.com>
Subject: Re: [PATCH 02/13] dt-bindings: i2c: nomadik: add mobileye,eyeq5-i2c bindings and example
Date: Fri, 16 Feb 2024 11:18:22 +0100	[thread overview]
Message-ID: <CZ6FD7EHIJDT.32IEDVT9FG2GP@bootlin.com> (raw)
In-Reply-To: <20240216022227.GA850600-robh@kernel.org>

Hello,

On Fri Feb 16, 2024 at 3:22 AM CET, Rob Herring wrote:
> On Thu, Feb 15, 2024 at 05:52:09PM +0100, Théo Lebrun wrote:
> > Add EyeQ5 bindings to the existing Nomadik I2C dt-bindings. Add the two
> > EyeQ5-specific properties behind a conditional. Add an example for this
> > compatible.

[...]

> > +allOf:
> > +  - $ref: /schemas/i2c/i2c-controller.yaml#
> > +  - if:
> > +      properties:
> > +        compatible:
> > +          contains:
> > +            const: mobileye,eyeq5-i2c
> > +    then:
> > +      properties:
> > +        mobileye,olb:
> > +          $ref: /schemas/types.yaml#/definitions/phandle
> > +          description: A phandle to the OLB syscon.
>
> Define properties at the top-level and then restrict them in if/then 
> schemas.

Noted, thanks.

> > +        mobileye,id:
> > +          $ref: /schemas/types.yaml#/definitions/uint32
> > +          description: Platform-wide controller ID (integer starting from zero).
>
> instance indexes are a NAK. You can use i2cN aliases if you must.
>
> Why do you need it? To access OLB? If so, add cell args to the OLB 
> phandle instead.

Why we do what we do: I2C controller must write a 2 bit value depending
on the bus speed. All I2C controllers write into the same register.
Index is used to compute the shift.

mobileye,olb is a phandle to a syscon. I'll be using i2cN aliases I
guess.

Thanks,

--
Théo Lebrun, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com

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