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    SubjectRe: [PATCH v7 07/13] dt-bindings: memory-controllers: add Exynos5422 DMC device description
    On Wed, May 8, 2019 at 4:45 AM Lukasz Luba <l.luba@partner.samsung.com> wrote:
    >
    >
    > On 5/8/19 9:19 AM, Krzysztof Kozlowski wrote:
    > > On Tue, 7 May 2019 at 19:04, Rob Herring <robh@kernel.org> wrote:
    > >>> +- devfreq-events : phandles of the PPMU events used by the controller.
    > >>> +- samsung,syscon-chipid : phandle of the ChipID used by the controller.
    > >>> +- samsung,syscon-clk : phandle of the clock register set used by the controller.
    > >>
    > >> Looks like a hack. Can't you get this from the clocks property? What is
    > >> this for?
    > >
    > > Hi Rob,
    > >
    > > Lukasz uses these two syscon regmaps to read certain registers. For
    > > chipid he reads it to check the size of attached memory (only 2 GB
    > > version is supported). This indeed looks like a hack. However the
    > > second regmap (clk) is needed to get the timing data from registers
    > > from DMC clock driver address space. These are registers with memory
    > > timing so their data is not exposed anyway in common clk framework.

    Okay, please just explain what your accessing. Consider adding the
    offset as a cell in case stuff moves around on another chip.

    > >
    > > Best regards,
    > > Krzysztof
    >
    > Thank you Krzysztof for a fast response. I have also responded to Rob.
    > I wouldn't call accessing chipid registers as a hack, though. The DMC
    > registers do not contain information about the memory chip since it is
    > in phase of production the board not the chip. Thus, chipid regs (which
    > loads from e-fuses) are best place to put information about memory
    > type/size.

    For efuses, we have a binding (nvmem). Maybe you should use it.

    Rob

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