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    SubjectRe: [spi-devel-general] [RESEND][PATCH] SPI: xilinx_spi: Added platform driver and support for DS570
    On Wednesday 24 June 2009, Richard Röjfors wrote:
    > On 09-06-23 21.37, David Brownell wrote:
    > > On Monday 15 June 2009, Richard Röjfors wrote:
    > >> This patch splits xilinx_spi into three parts, an OF and a platform
    > >> driver and generic part.
    > >>
    > >> The generic part now also works on X86 and also supports the Xilinx
    > >> SPI IP DS570
    > >
    > > Your Kconfig still mentions only DS464.
    > Correct, will update.

    Just checking -- you didn't send an update yet, right?

    > >> + See the "OPB Serial Peripheral Interface (SPI) (v1.00e)"
    > >> + Product Specification document (DS464) for hardware details.
    > >> +
    > >> +config SPI_XILINX_PLTFM
    > >> + tristate "Xilinx SPI controller platform device"
    > >> + depends on SPI_XILINX
    > >
    > > This should go first in the Kconfig, so that you don't goof up
    > > the dependency display ... the OF bits depend on it.
    > The OF parts only depend on SPI_XILINX, not SPI_XILINX_PLTFM. But
    > I can change the order anyway(?)

    Maybe I misread something. Make sure the Kconfig doesn't goof.

    > >> + /* devices to add to the bus when the host is up */
    > >> + struct spi_board_info *devices;
    > >> + u8 num_devices;
    > >
    > > This is duplicating functionality in the SPI core code.
    > > That's not really the way to fly.
    > I have discussed the same problem in the I2C list.
    > We have a PCIe device which is a MFD (multifunction device).
    > Several MFD devices could be connected to a standard PC ->
    > we don't know the bus numbers in advance, and there could be
    > several PCIe devices connected. Which mean the we can not use
    > spi_register_board_info.

    You could, actually, given metadata about those devices.
    That's one of the things ACPI does -- in a way that many
    of us find ugly! -- and the "device tree" some PPCs use.

    > We can not call spi_add_device from the MFD because when it's
    > probed the drivers for the SPI bus might not be available.

    And you can't call spi_register_board_info() there since
    the init section is gone.

    > So the solution in the I2C case was to add this into the driver
    > and if this tend to be a generic problem some generic solution might
    > be implemented.
    > So I would like to have the same thing in here.

    What I've done in such cases is make sure the bus adapter
    driver (in this case, for the spi_master) can issue some
    callback to code which makes spi_add_device(), or similar,

    But if your initialization doesn't have that sort of
    clean structure, it's probably kind of awkward to add
    it just now... :(

    - Dave

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