Driver Merge Questions

Driver Merge Questions

[Chris Hudson]

Hello all,

I've never submitted any software to Linux before, but I've been working 
on some new accelerometer drivers that should be ready for review soon 
(pending company approval).  I've read lots of documentation on patch 
and driver submissions, but I still have some questions that I was 
hoping someone could help me find the answers to.

1- My drivers use i2c for hardware communications, miscdevice for 
IOCTLs, and input_dev for data and interrupt status outputs.  Most of 
the other accelerometer drivers that I've looked at use similar designs 
and are located in drivers/hwmon, but I just wanted to confirm that this 
is the correct location currently.

2- I have done all of my hardware testing with OMAP development 
platforms, so I thought it would be best to send my patch submissions to 
this list for review.  The hardware monitoring tree is listed in 
MAINTAINERS as an orphan, but I was planning on including 
lm-sensors@lm-sensors.org as well.  If either of these assumptions is 
incorrect, please let me know.

3- Should my patch set consist of source, header, kconfig, and makefile 
patches, or should I include my custom changes to mux.c, mux.h, and 
board-zoom2.c as well?  The former are necessary for adding driver 
support, but the latter are specific for my hardware testing platform 
(which others may want to duplicate for testing purposes).  I noticed 
that recent versions of board-zoom2.c are nice and clean, so it's 
probably not a good idea to wedge infrequently-used code in there with a 
bunch of #ifdefs.  I just want to get an idea of what is generally 
included with a new driver.

Any help or advice would be greatly appreciated.

Thank you,

Chris Hudson
Kionix, Inc.

Re: Driver Merge Questions

[Tony Lindgren]

* Chris Hudson <chudson@kionix.com> [091103 06:48]:
> Hello all,
> 
> I've never submitted any software to Linux before, but I've been
> working on some new accelerometer drivers that should be ready for
> review soon (pending company approval).  I've read lots of
> documentation on patch and driver submissions, but I still have some
> questions that I was hoping someone could help me find the answers
> to.
> 
> 1- My drivers use i2c for hardware communications, miscdevice for
> IOCTLs, and input_dev for data and interrupt status outputs.  Most
> of the other accelerometer drivers that I've looked at use similar
> designs and are located in drivers/hwmon, but I just wanted to
> confirm that this is the correct location currently.

Sounds correct.
 
> 2- I have done all of my hardware testing with OMAP development
> platforms, so I thought it would be best to send my patch
> submissions to this list for review.  The hardware monitoring tree
> is listed in MAINTAINERS as an orphan, but I was planning on
> including lm-sensors@lm-sensors.org as well.  If either of these
> assumptions is incorrect, please let me know.

Yes, please send the patches to both. Also, please run the patches
through scripts/checkpatch.pl --strict, and read the files under
Documentation/Submit* ;)
 
> 3- Should my patch set consist of source, header, kconfig, and
> makefile patches, or should I include my custom changes to mux.c,
> mux.h, and board-zoom2.c as well?  The former are necessary for
> adding driver support, but the latter are specific for my hardware
> testing platform (which others may want to duplicate for testing
> purposes).  I noticed that recent versions of board-zoom2.c are nice
> and clean, so it's probably not a good idea to wedge
> infrequently-used code in there with a bunch of #ifdefs.  I just
> want to get an idea of what is generally included with a new driver.

Compile should work throughout the series for each patch to keep
git bisect working. To me it sounds like one patch for the driver,
and then one to enable the driver in some hardware.

Please not that we're reworking the mux code for omap3 to make it
easier to use. So please make the mux changes yet another patch.
 
> Any help or advice would be greatly appreciated.

Hope this helps!

Regards,

Tony

Re: Driver Merge Questions

[Amit Kucheria]

On 09 Nov 03, Tony Lindgren wrote:
> * Chris Hudson <chudson@kionix.com> [091103 06:48]:
> > Hello all,
> > 
> > I've never submitted any software to Linux before, but I've been
> > working on some new accelerometer drivers that should be ready for
> > review soon (pending company approval).  I've read lots of
> > documentation on patch and driver submissions, but I still have some
> > questions that I was hoping someone could help me find the answers
> > to.
> > 
> > 1- My drivers use i2c for hardware communications, miscdevice for
> > IOCTLs, and input_dev for data and interrupt status outputs.  Most
> > of the other accelerometer drivers that I've looked at use similar
> > designs and are located in drivers/hwmon, but I just wanted to
> > confirm that this is the correct location currently.
> 
> Sounds correct.

Unfortunately it will probably get rejected in drivers/hwmon. The maintainer,
Jean Delavare wants them out of hwmon[1]. It seems that everyone (for the
moment) is leaning towards a new subsystem called industrial IO
(drivers/staging/iio) for such drivers.

Please ask Jean before you do the work to make your driver behave like a hwmon
driver.

Regards,
Amit


[1] http://lkml.org/lkml/2009/7/2/153
-- 
-------------------------------------------------------------------------
Amit Kucheria,				 Kernel Developer, Verdurent
-------------------------------------------------------------------------

Re: Driver Merge Questions

[Amit Kucheria]

On Mon, Nov 9, 2009 at 11:26 AM, Amit Kucheria
<amit.kucheria@verdurent.com> wrote:
> On 09 Nov 03, Tony Lindgren wrote:
>> * Chris Hudson <chudson@kionix.com> [091103 06:48]:
>> > Hello all,
>> >
>> > I've never submitted any software to Linux before, but I've been
>> > working on some new accelerometer drivers that should be ready for
>> > review soon (pending company approval).  I've read lots of
>> > documentation on patch and driver submissions, but I still have some
>> > questions that I was hoping someone could help me find the answers
>> > to.
>> >
>> > 1- My drivers use i2c for hardware communications, miscdevice for
>> > IOCTLs, and input_dev for data and interrupt status outputs.  Most
>> > of the other accelerometer drivers that I've looked at use similar
>> > designs and are located in drivers/hwmon, but I just wanted to
>> > confirm that this is the correct location currently.
>>
>> Sounds correct.
>
> Unfortunately it will probably get rejected in drivers/hwmon. The maintainer,
> Jean Delavare wants them out of hwmon[1]. It seems that everyone (for the

s/Delavare/Delvare
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Re: Driver Merge Questions

[Chris Hudson]

Hello Amit,

Thank you for the information.

The driver is just about finished actually; I was going to do some final 
testing and pull and submit the patches today.  I read the lkml.org 
source and it definitely seems like things are in a state of limbo at 
the moment (well, as of a few months ago) with regard to sensor 
drivers.  So, should I submit the code as-is and work on changing it as 
necessary with the help of the community, or do I step back and modify 
for the iio subsystem before submission?  Alternatively, since the code 
was originally written for the 2.6.29 Android kernel, should I submit 
the current version of the driver to that branch first?  Please let me know.

Thank you,
Chris

Amit Kucheria wrote:
> On 09 Nov 03, Tony Lindgren wrote:
>   
>> * Chris Hudson <chudson@kionix.com> [091103 06:48]:
>>     
>>> Hello all,
>>>
>>> I've never submitted any software to Linux before, but I've been
>>> working on some new accelerometer drivers that should be ready for
>>> review soon (pending company approval).  I've read lots of
>>> documentation on patch and driver submissions, but I still have some
>>> questions that I was hoping someone could help me find the answers
>>> to.
>>>
>>> 1- My drivers use i2c for hardware communications, miscdevice for
>>> IOCTLs, and input_dev for data and interrupt status outputs.  Most
>>> of the other accelerometer drivers that I've looked at use similar
>>> designs and are located in drivers/hwmon, but I just wanted to
>>> confirm that this is the correct location currently.
>>>       
>> Sounds correct.
>>     
>
> Unfortunately it will probably get rejected in drivers/hwmon. The maintainer,
> Jean Delavare wants them out of hwmon[1]. It seems that everyone (for the
> moment) is leaning towards a new subsystem called industrial IO
> (drivers/staging/iio) for such drivers.
>
> Please ask Jean before you do the work to make your driver behave like a hwmon
> driver.
>
> Regards,
> Amit
>
>
> [1] http://lkml.org/lkml/2009/7/2/153
>   

Re: Driver Merge Questions

[Amit Kucheria]

On 09 Nov 09, Chris Hudson wrote:
> Hello Amit,
> 
> Thank you for the information.
> 
> The driver is just about finished actually; I was going to do some
> final testing and pull and submit the patches today.  I read the
> lkml.org source and it definitely seems like things are in a state
> of limbo at the moment (well, as of a few months ago) with regard to
> sensor drivers.  So, should I submit the code as-is and work on
> changing it as necessary with the help of the community, or do I
> step back and modify for the iio subsystem before submission?
> Alternatively, since the code was originally written for the 2.6.29
> Android kernel, should I submit the current version of the driver to
> that branch first?  Please let me know.

Hi Chris,

No harm is submitting a patch for a hwmon-based driver against mainline
2.6.32-rc6 to LKML (cc the requisite maintainers). It might help get review on
obvious issues, if any. 

But be prepared to modify the driver to use IIO. I just modified a driver to
use IIO and isn't that hard - probably an afternoon's work.

Regards,
Amit
-- 
-------------------------------------------------------------------------
Amit Kucheria,				 Kernel Developer, Verdurent
-------------------------------------------------------------------------