Re: Accessing SPI

Thank you, Geert.

Now I am able to create /dev/spidev1.1 and open it from the test code
in Documents/spi.

Now I am not able to see any activity on the hardware, even though all
software seems fine.

Here is the setup:
-        SmartFusion2 board, Emcraft 1.12 distro
-       The test app Geert mentioned, built in Emcraft tree and renamed
-        No slave device, just the naked demo board
-        Oscilloscope

First I verify that the scope sees the reference signal provided by
the scope itself. It does.
When I probe pin 17 (P7->17) on the breadboard, I see it HIGH. This
looks like SPI1_SS/ (it is doc'd as such).
When I probe pin 18 on the breadboard, looking for SPI1_CLK, it is
LOW. When the port is idle, this is expected.

When I fire up the test code, I expect to see SPI1_SS/ move LOW and
the clock signal asserted during the transfer.
------I SEE NOTHING-----


Have I overlooked a step?


On Wed, Jan 29, 2014 at 2:19 AM, Geert Uytterhoeven
<[email protected]> wrote:
> On Wed, Jan 29, 2014 at 12:45 AM, Eric Fowler <[email protected]> wrote:
>> I did find a file, linux/spi/spidev.h, that has a struct defined that seems
>> to be used by user mode SPI code, but it is not clear how I am to use it, in
>> particular, which IOCTLs are available, and how I can get access to the
>> interface at low levels.
>
> Please see the Linux kernel documentation, with examples:
>
>     Documentation/spi/spidev
>     Documentation/spi/spidev_fdx.c
>     Documentation/spi/spidev_test.c
>
> Gr{oetje,eeting}s,
>
>                         Geert
>
> --
> Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- [email protected]
>
> In personal conversations with technical people, I call myself a hacker. But
> when I'm talking to journalists I just say "programmer" or something like that.
>                                 -- Linus Torvalds
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