User space drivers

User space drivers

[Wallace, Brooke]

Hi,
 
I've been trying to sort thru the ALSA docs and am starting to get the
impression that all of the existing drivers are written as Kernel
Modules. Doesn't this mean that they are running in Kernel space and
infact are not User Space drivers? Shouldn't there be an ALSA Drivers
API document that covers an API that User Space Drivers can use? I must
be mssing something here...
 
I'm looking into ALSA because my company wants to use this standard for
writing User Space drivers for our product running on various linux
kernels. The reasoning for this is strictly proprietary licensing - our
leagl department is not comfortable with the GPL and the possiblitiy
that something written for Kernel space could at some time be considered
as required to be GPL - not my decision...
 
-Brooke

Re: User space drivers

[Rene Herman]

On 08/02/2007 11:39 PM, Wallace, Brooke wrote:

> I've been trying to sort thru the ALSA docs and am starting to get the 
> impression that all of the existing drivers are written as Kernel 
> Modules.

Yes. Some stuff like mixing happens in userspace but the lowlevel drivers 
are in kernel space.

> Doesn't this mean that they are running in Kernel space and infact are
> not User Space drivers?

Yes.

> Shouldn't there be an ALSA Drivers API document that covers an API that
> User Space Drivers can use? I must be mssing something here...

I believe you are. Who told you that ALSA drivers ran in userspace?

> I'm looking into ALSA because my company wants to use this standard for 
> writing User Space drivers for our product running on various linux 
> kernels. The reasoning for this is strictly proprietary licensing - our 
> leagl department is not comfortable with the GPL and the possiblitiy that
> something written for Kernel space could at some time be considered as
> required to be GPL - not my decision...

You have a sensible legal department. Many hold that distributing Linux 
kernelspace code under a non GPL compatible license is illegal, period.

Your job, should you chose to accept it, is convince them that releasing the 
code you will be writing under a GPL compatible license is not actually all 
that scary. Pointing them to all the other companies that do so can help.

The other option you have is make do without _any_ help from _anyone_ on 
this list at least. Good luck.

Rene.

Re: User space drivers

[James Courtier-Dutton]

Wallace, Brooke wrote:
> Hi,
>  
> I've been trying to sort thru the ALSA docs and am starting to get the
> impression that all of the existing drivers are written as Kernel
> Modules. Doesn't this mean that they are running in Kernel space and
> infact are not User Space drivers? Shouldn't there be an ALSA Drivers
> API document that covers an API that User Space Drivers can use? I must
> be mssing something here...
>  
> I'm looking into ALSA because my company wants to use this standard for
> writing User Space drivers for our product running on various linux
> kernels. The reasoning for this is strictly proprietary licensing - our
> leagl department is not comfortable with the GPL and the possiblitiy
> that something written for Kernel space could at some time be considered
> as required to be GPL - not my decision...
>  
> -Brooke
>  

Brooke,

What is the problem? Just license your driver as GPL. Result, no more 
legal problems.
The advantage of this approach is that you then get to use your device 
with Linux. Alternatives along the lines of what you are considering are 
not worth the effort by yourselves, and certainly not worth our effort 
helping you.

Kind Regards

James

Re: User space drivers

[Eliot Blennerhassett]

James Courtier-Dutton wrote:
> Wallace, Brooke wrote:
>> Hi,
>>  
>> I've been trying to sort thru the ALSA docs and am starting to get the
>> impression that all of the existing drivers are written as Kernel
>> Modules. Doesn't this mean that they are running in Kernel space and
>> infact are not User Space drivers? Shouldn't there be an ALSA Drivers
>> API document that covers an API that User Space Drivers can use? I must
>> be mssing something here...

What you may be looking for is the plugins API.
Take a look at the alsa-plugins source, there are some examples of
things that talk to other userspace things (E.g. jack or pulseaudio
plugin) or other non alsa drivers (E.g. oss or freebob)

http://hg-mirror.alsa-project.org/alsa-plugins/

But remember not to put any GPL code in your non-gpl driver ;)

As others have mentioned you may not be able to get much help for this
kind of endeavour if you are not prepared to "show us the source".

--
Eliot

User space drivers

[bmentink]

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Hi all,

I am wanting to implement a user space driver complete with interrupt in yocto.
I see that there is a sample generic platform driver in the kernel, but not sure how to use it.

Say i want to talk to GPIO Is it simply a matter of pointing the .dts entry for the driver to the uio driver?

Any pointers would be very helpful ..

Cheers,
Bernie



Sent from Samsung tablet

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Re: User space drivers

[Pow, Christopher (SWCOE)]

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Linux documentation is very clear on how to interact with GPIO from user space application and even use them as interrupts.  Refer to Documentation/gpio.txt, section “Sysfs Interface for Userspace (OPTIONAL)” – also make sure you enable the sysfs portion of gpiolib in menuconfig (CONFIG_GPIO_SYSFS).

Christopher S. Pow
Senior Engineer, Systems
Honeywell SWCOE - RTOS
o:612-951-5852 c:612-910-1271

"The number you have dialed is imaginary.  Please rotate your phone 90 degrees and try again."

From: meta-ti-bounces@yoctoproject.org [mailto:meta-ti-bounces@yoctoproject.org] On Behalf Of bmentink
Sent: Friday, October 04, 2013 1:28 PM
To: meta-ti@yoctoproject.org
Subject: [meta-ti] User space drivers


Hi all,

I am wanting to implement a user space driver complete with interrupt in yocto.
I see that there is a sample generic platform driver in the kernel, but not sure how to use it.

Say i want to talk to GPIO Is it simply a matter of pointing the .dts entry for the driver to the uio driver?

Any pointers would be very helpful ..

Cheers,
Bernie



Sent from Samsung tablet

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Re: User space drivers

[Denys Dmytriyenko]

Also, you may find this project interesting:

https://github.com/jackmitch/libsoc

-- 
Denys


On Fri, Oct 04, 2013 at 06:42:22PM +0000, Pow, Christopher (SWCOE) wrote:
> Linux documentation is very clear on how to interact with GPIO from user 
> space application and even use them as interrupts.  Refer to 
> Documentation/gpio.txt, section “Sysfs Interface for Userspace (OPTIONAL)” – 
> also make sure you enable the sysfs portion of gpiolib in menuconfig 
> (CONFIG_GPIO_SYSFS).
> 
> Hi all,
> 
> I am wanting to implement a user space driver complete with interrupt in 
> yocto. I see that there is a sample generic platform driver in the kernel, 
> but not sure how to use it.
> 
> Say i want to talk to GPIO Is it simply a matter of pointing the .dts entry 
> for the driver to the uio driver?
> 
> Any pointers would be very helpful ..