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SubjectRe: [v2 2/2] fpga: Add support for Lattice iCE40 FPGAs
Hi Joel,

On Mon, Oct 24, 2016 at 9:51 PM, Joel Holdsworth
<> wrote:

> I think my set_cs() function is ok-ish. It's copied from spi_set_cs() in
> drivers/spi/spi.c . This function is a static internal helper, so I
> copy/pasted the function into the ice40 driver. Given that it's only 4-lines
> of code, it didn't seem too bad - though I'm not exactly sure why
> spi_set_cs() isn't a public API. It seems like quite a common-place thing to
> need to do with certain devices.
> However, perhaps the function is internal because the authors of the SPI
> framework foresaw how easy it would be to screw up a shared bus with that
> function. I had to take care to make sure the SPI bus was locked throughout.
> Do you agree that it's the right thing to copy the function in? Or do you
> think it would be better to ask for spi_set_cs to be exposed publicly?

I'd poke the SPI maintainers about what their reasoning was to make it
and how they'd go about doing what you're trying to do.
I can imagine there might be some SPI controllers where the above
doesn't work well,
because the controller automatically handles the CS line and you don't
get control over it.



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