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    SubjectRe: [PATCH 2.6-git] SPI: add set_clock() to bitbang
    David Brownell wrote:

    >>No, suppose there're two devices behind the same SPI bus that have
    >>different clock constraints. As active SPI device change may well happen
    >>when each new message is processed, we'll need to set up clocks again
    >>for each message. Right?
    >>
    >>
    >
    >Clock is coupled to chipselect/device. When the bus controller
    >switches to the other device, it updates the clock accordingly.
    >
    >
    Yeah, but chipselect is called on per-transfer basis what is likely to
    be redundant for clock setting.
    Per-message clock configuration is enough AFAIS.

    >How exactly that's done is system-specific. Many controllers
    >just have a register per chipselect, listing stuff like SPI mode,
    >clock divisor, and word size. So switching to that chipselect
    >kicks those in automatically ... devices ignore the clock unless
    >they've been selected.
    >
    >
    Hmm, usually clocks are configured for the bus not device.
    So, summarizing, you haven't convinced me yet. :)

    Vitaly
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