Re: [PATCH RFC 2/2] mfd: add Renesas RPC-IF driver

[Lee Jones <lee.jones@xxxxxxxxxx>]

On Tue, 18 Jun 2019, Sergei Shtylyov wrote:

> Hello!
> 
> On 06/18/2019 02:34 PM, Lee Jones wrote:
> 
> >>>>> So is an RPC-IF a real hardware device.  Can you share the datasheet?
> >>>>
> >>>> Unfortunately the datasheet for the R-Car Gen3 and RZ/G2 SoCs is
> >>>> not yet public.
> >>>
> >>> When will it be public?
> >>
> >> Dunno. RZ/G1 documentation became public a few months after the SoC
> >> release.
> >>
> >>> Do you have access to it?
> >>
> >> Yes I do.
> > 
> > Great.  Maybe you can help Sergei with his 'undocumented bits' issue.
> 
>    You're an optimist. :-)
>    I think I have the same gen3 manual v1.50 as Geert. It won't help as the
> bits that constitute the magic numbers in the driver are not described (not
> even the default values are listed for the most of them).

Then how did you get hold of them?

> >>>> However, a very similar hardware block is present in the RZ/A2M SoC.
> >>>> Please see Chapter 20 ("SPI Multi I/O Bus Controller") of the "RZ/A2M Group
> >>>> User’s Manual: Hardware", which you can download from
> >>>> https://www.renesas.com/eu/en/products/microcontrollers-microprocessors/rz/rza/rza2m.html#documents
> >>>
> >>>   "The SPI multi I/O bus controller enables the direct connection of
> >>>    serial flash, OctaFlashTM, XccelaTM flash, or HyperFlashTM memory
> >>>    devices to this LSI chip.
> >>>
> >>>    This module allows the connected serial flash, OctaFlashTM, XccelaTM
> >>>    flash, or HyperFlashTM memory devices to be accessed by reading the
> >>>    external address space, or using Manual mode to transmit and receive
> >>>    data."
> >>>
> >>> Looks like a flash device to me.
> >>
> >> The external address space is a small window.
> 
>    Yeah, it only provides 64 MiB window into the flash chip.
> 
> >>> Can the SPI portion be used to connect generic SPI devices?
> >>
> >> I'll defer that to the people who worked on the driver...
> 
>    Yes. Or at least it should, looking at the driver code...

Judging by that response, I'm guessing that this is unused/untested.

-- 
Lee Jones [李琼斯]
Linaro Services Technical Lead
Linaro.org │ Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog