drivers for usb daq card

drivers for usb daq card

[Prashant Shah]

Hi,

I am total newbie and this is my first device drivers. I am trying to
write drivers for National Instruments USB 6008 USB based data
acquisition card.

I was initially trying to do that with the comedi based system but I
was suggest to try working with the IIO sub system. I was reading
through the IIO docs and IIO seems to be more targeted to SPI and I2C
systems. I am not sure about how good is the support for USB based
systems. I am newbie so I dont want to do something that will be hard
for me to work with :)

Also, we already have user space applications that interface with
comedi like scilab and xoscope, etc. Will these applications that use
the comedi based interface work with IIO ?

Regards.

Re: drivers for usb daq card

[Jonathan Cameron]

On 04/30/11 08:33, Prashant Shah wrote:
> Hi,
> 
> I am total newbie and this is my first device drivers. I am trying to
> write drivers for National Instruments USB 6008 USB based data
> acquisition card.
> 
> I was initially trying to do that with the comedi based system but I
> was suggest to try working with the IIO sub system. 
That's curious. I was going to suggest you looked at comedi!
Out of interest, what was the reason given?
> I was reading
> through the IIO docs and IIO seems to be more targeted to SPI and I2C
> systems. I am not sure about how good is the support for USB based
> systems. 
Everything is bus independent. It just happens that our current parts
are all spi or i2c.
> I am newbie so I dont want to do something that will be hard
> for me to work with :)
Two initial questions.  Do you have the full docs? NI haven't been
helpful to my requests in the past (which has put me off ever using
their kit again).  Secondly, why does this want to be in kernel space?
Limitations of the usb bus often mean you can do almost as well
with a userspace driver and they tend to be easier to write / debug.
Based on a quick look at NI's website, I'd suggest doing a userspace
driver first for this part anyway to make sure you understand the
underlying interface to the device. libusb is great for this sort of
thing!
> 
> Also, we already have user space applications that interface with
> comedi like scilab and xoscope, etc. Will these applications that use
> the comedi based interface work with IIO ?
Not directly. The issue of sharing interfaces has been raised before
but I don't think any firm proposals have been made. Robin, are 
you aware of any progress on this?  It would probably be possible to
do this as a userspace library (I think all comedi calls go through
a library?).

Good luck!

Jonathan
> 
> Regards.
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Re: drivers for usb daq card

[Prashant Shah]

Hello,

On Sat, Apr 30, 2011 at 3:39 PM, Jonathan Cameron <jic23@cam.ac.uk> wrote:
> On 04/30/11 08:33, Prashant Shah wrote:
>> Hi,
>> I was initially trying to do that with the comedi based system but I
>> was suggest to try working with the IIO sub system.
> That's curious. I was going to suggest you looked at comedi!
> Out of interest, what was the reason given?

http://lists.kernelnewbies.org/pipermail/kernelnewbies/2011-April/001616.ht=
ml

>> I am newbie so I dont want to do something that will be hard
>> for me to work with :)
> Two initial questions. =A0Do you have the full docs? NI haven't been
> helpful to my requests in the past (which has put me off ever using
> their kit again).

I dont have any docs other than what is available on their website. Is
it possible to track the usb traffic and work with that. The device
that I am working with in pretty basic and we are interested in only
the getting the analog input data for the time being.

> Secondly, why does this want to be in kernel space?

There are few similar devices in the staging/comedi/drivers area. I am
just following them! I dont know whether comedi can work with libusb.

Thanks.

Re: drivers for usb daq card

[Jonathan Cameron]

Hi

Firstly sorry for the extremely slow reply.  I read the email on my phone
and as I haven't figured out how to reply inline, I thought - I'll do it
tomorrow - then completely forgot.  Ooops.
> 
> On Sat, Apr 30, 2011 at 3:39 PM, Jonathan Cameron <jic23@cam.ac.uk> wrote:
>> On 04/30/11 08:33, Prashant Shah wrote:
>>> Hi,
>>> I was initially trying to do that with the comedi based system but I
>>> was suggest to try working with the IIO sub system.
>> That's curious. I was going to suggest you looked at comedi!
>> Out of interest, what was the reason given?
> 
> http://lists.kernelnewbies.org/pipermail/kernelnewbies/2011-April/001616.html
Hmm. Greg may be speculating a touch there.  New drivers maybe...
> 
>>> I am newbie so I dont want to do something that will be hard
>>> for me to work with :)
>> Two initial questions.  Do you have the full docs? NI haven't been
>> helpful to my requests in the past (which has put me off ever using
>> their kit again).
> 
> I dont have any docs other than what is available on their website. Is
> it possible to track the usb traffic and work with that.
It's certainly possible and having looked at the above post I see you have
made some progress. Any luck getting it working?
> The device
> that I am working with in pretty basic and we are interested in only
> the getting the analog input data for the time being.
> 
>> Secondly, why does this want to be in kernel space?
> 
> There are few similar devices in the staging/comedi/drivers area. I am
> just following them! I dont know whether comedi can work with libusb.
Directly, it probably can't.  Comedi goes through a library though (iirc)
so it would probably be possible to do things at that level.

Jonathan

Re: drivers for usb daq card

[Prashant Shah]

Hi,

On Thu, May 12, 2011 at 7:37 PM, Jonathan Cameron <jic23@cam.ac.uk> wrote:
> Hi
>
>> On Sat, Apr 30, 2011 at 3:39 PM, Jonathan Cameron <jic23@cam.ac.uk> wrote:
>>> On 04/30/11 08:33, Prashant Shah wrote:
>> I dont have any docs other than what is available on their website. Is
>> it possible to track the usb traffic and work with that.

> It's certainly possible and having looked at the above post I see you have
> made some progress. Any luck getting it working?

Not yet. I think it will be much easier for me to first write a normal
USB driver for the device and then convert that to comedi. That is
what I am upto next.

Regards.