Re: [Gumstix-users] SPIDEV image

[Kimberly T. <kim...@gm...>]

Hey Adam -

I just spent a few weeks fighting through this (I'm a linux newbie) so
here's the step-by-step I did.  A word of warning - it's probably better to
do this with patching, but I had some issues getting that to work with a
bitbake recipe, so here's a quick and dirty solution to get you started, and
you can worry about patch generation later.  I'd recommend saving copies of
the originals before you start making edits, and of the edited files once
you generate them.  I've assumed the standard file set-up from the
Gumstix.net getting started website, and use of Kernel 2.6.32.  Adjust these
instructions according to any changes you've made to that setup.

*EDIT*: overo-oe/tmp/work/git/arch/arm/mach-omap2/board-overo.c
      *REPLACE*: the body of
static struct spi_board_info overo_spi_board_info[] __initdata = {
        {
                .modalias               = "ads7846",
                .bus_num                = 1,
                .chip_select            = 0,
                .max_speed_hz           = 1500000,
                .controller_data        = &ads7846_mcspi_config,
                .irq                    =
OMAP_GPIO_IRQ(OVERO_GPIO_PENDOWN),
                .platform_data          = &ads7846_config,
        }
};
            *WITH*:
          {
                   .modalias = "spidev",
               .max_speed_hz = <YOUR DEVICE SPEED>,
               .bus_num = 1,
               .chip_select = <1 or 0>,
        }

[Assuming you don't need the touchscreen, which I did not.  If you do need
the touchscreen, make a separate entry directly after the ads7846 entry, and
you will have to put your device on chip select 1].

         *ENSURE:* that static void __init overo_init(void) calls
overo_spi_init(), which calls spi_register_board_info(overo_spi_board_info,
ARRAY_SIZE(overo_spi_board_info))

[Or some equivalent set of calls that will make register the board info you
edited]

--------------

*COPY: *The folder of linux recipes from
overo-oe/org.openembedded/recipes/linux
     *TO: *A user created folder in overo-oe:
overo-oe/user.collection/recipes/linux
*EDIT: *
overo-oe/user.collection/recipes/linux/linux-omap3-2.6.32/overo/defconfig
     *CHANGE:* CONFIG_TOUCHSCREEN_ADS7846=y
and/or CONFIG_TOUCHSCREEN_ADS7846=m to #CONFIG_TOUCHSCREEN_ADS7846 is not
set.
     *ENSURE:* CONFIG_SPI_SPIDEV=y is in the defconfig, otherwise add it.
[You can either do this all manually, or you can type:
bitbake -c menuconfig linux-omap3, and scroll to the device drivers, and SPI
devices and make the changes there.  SPIDEV should already appear as an
option.]

--------------

Once these changes have been made,
*TYPE:*
bitbake -c compile linux-omap3
bitbake linux-omap3

Since SPIDEV is already being created and stored, I'm pretty sure you can
just change the uImage file on your MicroSD card to the new one you've
created. If you don't see spidev, then you might try replacing the rootfs as
well.  As I recall though, these instructions created spidev1.0 in the /dev/
file automatically.

-----------------

Let me know if you run into any trouble, and anyone on this list is welcome
to correct my methods here.  I had some trouble getting spidev to do what I
wanted, so you might try checking out the simple SPI drivers Scott Ellis
created http://github.com/scottellis/ if you end up in the same situation.

Good luck!

-Kim



On Sat, Apr 10, 2010 at 10:12 PM, Adam Stambler <ad...@gm...> wrote:

> Hello Folks,
>
> I am about am trying to set up my Overo Fire to talk to an AVR
> microcontroller expansion board over SPI.  It is a little robot expansion
> board that I made.  Since the interface is very simple and there is not much
> data going between them, I would like to use SPIDEV rather than write my own
> driver from scratch.
>
> Does anyone have an gumstix image with spidev already enabled?  Would you
> be willing to share it?  There are a bunch of threads on the mailing list,
> but the instructions are a bit disperse and hard to follow.  It would be a
> great help if someone could point me to a prebuilt image or concise
> instructions.  If not, I will slog through the mailing list threads.
>
> Thank you for the help.
>
> Regards,
> Adam Stambler
>
>
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-- 
Kim Turley
kim...@gm...