From: <nwk...@gmail.com>
Reply-To: "beagleboard@googlegroups.com" <beagleboard@googlegroups.com>
Date: Tuesday, July 29, 2014 at 7:33 AM
To: "beagleboard@googlegroups.com" <beagleboard@googlegroups.com>
Subject: Re: [beagleboard] Using SPI in a kernel module
> Thanks, John.
>
> I Iooked at kernel/drivers/iio/dac/ad/5064.c
>
> There's the following struct which is passed to spi_register_driver():
> static struct spi_driver ad5064_spi_driver = {
> .driver = {
> .name = "ad5064",
> .owner = THIS_MODULE,
> },
> .probe = ad5064_spi_probe,
> .remove = ad5064_spi_remove,
> .id_table = ad5064_spi_ids,
> };
>
> I compiled the module and loaded it but the probe function never gets called.
> Why?
>From this I can see that this driver isn¹t DeviceTree enabled so I¹m not
sure which SPI interface it is using. Either you can add the devicetree
support to this driver so that you can specify which SPI interface to use,
or e-mail the Linux-IIO mailing list and see how to use this driver.
Regards,
John
>
>
>
> Am Montag, 28. Juli 2014 18:09:34 UTC+2 schrieb john3909:
>>
>> From: Nils <nwk...@gmail.com <javascript:> >
>> Reply-To: "beagl...@googlegroups.com <javascript:> "
>> <beagl...@googlegroups.com <javascript:> >
>> Date: Monday, July 28, 2014 at 7:00 AM
>> To: "beagl...@googlegroups.com <javascript:> " <beagl...@googlegroups.com
>> <javascript:> >
>> Subject: [beagleboard] Using SPI in a kernel module
>>
>>> Hello,
>>>
>>> I'm currently working on a kernel module which needs to communicate via SPI
>>> to an external microchip.
>>>
>>> I used the cape manager to enable SPI. The device is accessible through
>>> /dev/spidev1.0.
>>> But since it's a kernel module, I guess it's not recommended to access files
>>> via sys_open()?
>>>
>>> Another approach I found would be adding a struct to
>>> arch/arm/mach-omap2/board-am335xevm.c and then use spi_register_driver() in
>>> my kernel module. But in my kernel sources (3.8.13) this file doesn't exist.
>> There is no board files since the introduction of device tree.
>>>
>>>
>>> What would be the right way to use SPI in my kernel module?
>> Look at examples in /drivers/staging/iio or /drivers/iio
>>
>> There are plenty of examples of using SPI calls in a kernel module.
>>
>> Use the power of GIT to find what you are looking for. In the Kernel source
>> do the following:
>>
>> git grep spi_sync_transfer
>>
>> Regards,
>> John
>>>
>>>
>>> Regards,
>>> Nils
>>>
>>> --
>>> For more options, visit http://beagleboard.org/discuss
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>
> --
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