Re: [PATCH/RFC 4/6] dt-bindings: i2c: renesas,iic: Convert to json-schema

[Rob Herring <robh@kernel.org>]

On Tue, May 04, 2021 at 04:51:11PM +0200, Geert Uytterhoeven wrote:
> Convert the Renesas R-Mobile I2C Bus Interface (IIC) Device Tree binding
> documentation to json-schema.
> 
> Document missing properties.
> R-Mobile A1 and SH-Mobile have multiple interrupts.
> Update the example to match reality.
> 
> Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
> ---
> It is still not clear to me which instances on R-Car Gen2 and RZ/G1
> support automatic transmission, cfr. this note for the IIC3 instance in
> the Hardware User's Manual:
> 
>     Automatic transmission for PMIC control (DVFS) is not available
>     because the second generation R-Car series and RZ/G series products
>     do not support the DVFS function (automatic transmission can be used
>     as a hardware function, but this is not meaningful for actual use
>     cases).
> 
> The only thing that's clear is that R-Car E2 and RZ/G1E do not have the
> automatic transmission registers.  Note that current r8a7745.dtsi and
> r8a7794.dtsi do not reflect that.
> 
> This binding interpretes the note as that IIC3 does not support
> automatic transmission on R-Car H2, M2-W, M2-N, and V2H, and RZ/G1H,
> RZ/H1M, RZ/G1N, while the other (if any) IIC instances on these SoCs do
> support automatic transmission.  This matches with the current
> r8a774[234].dtsi, which do not declare compatibility with the
> family-specific and generic versions.  Note that the current
> r8a779[0123].dtsi still do, and thus should be updated!
> 
> Possible alternative interpretations of the note are:
>   - Only IIC3 has the automatic transmission registers.  But the
>     automatic transmission feature is not useful as the SoCs lack DVFS
>     support.
>   - All IIC instances have the automatic transmission registers, and
>     IIC3 is traditionally used to control the PMIC.  But as the SoCs
>     lack DVFS support, the automatic transmission feature is not useful.
>     As R-Car V2H has only instance IIC3, and is documented to have
>     automatic transmissiong registers, this might be the correct
>     interpration?
>   - Anything else?

Can't help there, but looks fine otherwise.

Reviewed-by: Rob Herring <robh@kernel.org>

> 
> Thanks for your comments!
> ---
>  .../devicetree/bindings/i2c/renesas,iic.txt   |  72 --------
>  .../bindings/i2c/renesas,rmobile-iic.yaml     | 160 ++++++++++++++++++
>  MAINTAINERS                                   |   2 +-
>  3 files changed, 161 insertions(+), 73 deletions(-)
>  delete mode 100644 Documentation/devicetree/bindings/i2c/renesas,iic.txt
>  create mode 100644 Documentation/devicetree/bindings/i2c/renesas,rmobile-iic.yaml