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

Théo Lebrun
2024-02-16T10:40:52Z

Hello,

On Fri Feb 16, 2024 at 11:33 AM CET, Krzysztof Kozlowski wrote:
> On 16/02/2024 11:18, Théo Lebrun wrote:
> >
> >>> + 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.
>
> Which register? Your devices do not share IO address space.

mobileye,olb is a prop with a phandle to a syscon. That syscon contains
the register we are interested in.

The Linux code side of things is in the following patch. We use
syscon_regmap_lookup_by_phandle().

[PATCH 10/13] i2c: nomadik: support Mobileye EyeQ5 I2C controller
https://lore.kernel.org/lkml/20240215-mbly-i2c-v1-10-19a336e91dca@bootlin.com/

Thanks,

--
Théo Lebrun, Bootlin
Embedded Linux and Kernel engineering