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    SubjectRe: [RFC PATCH 0/1] Portable Device Tree Connector -- conceptual
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    On 07/04/16 08:22, Mark Brown wrote:
    > On Sat, Jul 02, 2016 at 04:55:49PM -0700, frowand.list@gmail.com wrote:
    >
    >> This is an extremely simple example to illustrate the concepts. It is not
    >> meant to represent the complexity of a real board.
    >>
    >> To start with, assume that the device that will eventually be on a daughter
    >> board is first soldered onto the mother board. The mother board contains
    >> two devices connected via bus spi_1. One device is described in the .dts
    >> file, the other is described in an included .dtsi file.
    >> Then the device tree files will look like:
    >
    > Can I suggest not using SPI as an example here? It's particularly
    > messy since addresses are essentially just a random signal that can be
    > totally separate to the controller hardware which might be adding more
    > complexity early on in building up your model than is really desirable.
    > It will need to be dealt with but perhaps not right now. I2C might be
    > easier.
    >
    > The initial issue with SPI is that you really need to do something like
    > bring out individual slots on the bus rather than the bus as a whole
    > since you're going to need a remapping layer to map chip selects on the
    > module to chip selects on the host board.
    >

    Yes, thank you for pointing that out.

    For the purposes of the mental model, when thinking about what I wrote,
    just change SPI to I2C everywhere.

    -Frank

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