Example for buffer-dmaengine?

Example for buffer-dmaengine?

[Crash House]

Hello everyone,

(Never done this before, let me know if I do anything incorrectly).

I am looking for a dummy example on using the iio/buffer-dmaengine

I have found several SDR examples in the linux/driver/iio/adc. However
I am struggling to implement a simple version of them myself.

The main road block I have currently seems to be a different between
the AnalogDevicesInc github project and Torvalds. Specifically the
difference is in  “linux/include/linux/iio/buffer-dmaengine.h”. One
takes 2 arguments and the other 4.

Along with this when attempting to add a module that uses dmaEngine I
get the following dmesg: “Unknown symbol iio_dmaengine_buffer_alloc”

Am I missing something stupid?
Am I using an obsolete functionality?
Should I be using iio/kfifo_buf.h?

Thanks everyone,

John

Re: Example for buffer-dmaengine?

[Popa, Stefan Serban]

On Lu, 2019-01-21 at 16:20 -0500, Crash House wrote:
> Hello everyone,
> 
> (Never done this before, let me know if I do anything incorrectly).
> 
> I am looking for a dummy example on using the iio/buffer-dmaengine
> 
> I have found several SDR examples in the linux/driver/iio/adc. However
> I am struggling to implement a simple version of them myself.
> 
> The main road block I have currently seems to be a different between
> the AnalogDevicesInc github project and Torvalds. Specifically the
> difference is in  “linux/include/linux/iio/buffer-dmaengine.h”. One
> takes 2 arguments and the other 4.
> 
> Along with this when attempting to add a module that uses dmaEngine I
> get the following dmesg: “Unknown symbol iio_dmaengine_buffer_alloc”
> 
> Am I missing something stupid?
> Am I using an obsolete functionality?
> Should I be using iio/kfifo_buf.h?
> 
> Thanks everyone,
> 
> John

Hello John,

Here's an example which uses the buffer-dmaengine, which is as simple as it
gets: https://github.com/analogdevicesinc/linux/blob/master/drivers/iio/adc
/ad7768.c.

Unfortunately, it's not upstream, mainly for the reasons you have pointed
out above. There is a difference between the Analog Devices buffer-
dmaengine and the upstream version.
I hope this helps.

-Stefan