On Mon, Feb 10, 2014 at 09:45:20AM +0100, Bjørn Mork wrote:
Johannes Thumshirn <johannes.thumshirn@men.de> writes:
Hi,
I have a question regarding driver submission into mainline. I'm not exactly sure if my driver is ready to be submittet into normal drivers or if it would be better to submit it to staging first.
New drivers do not normally go through staging. If your driver is mostly following the kernel coding standards and using appropriate kernel interfaces, then, in my opinion, there is no reason to submit it to staging first. I'd submit as a normal driver first, and then only consider staging if the initial feedback indicates that major changes are necessary before the driver is ready for mainline.
My impression is that staging is primarily for code which was written without Linux mainline in mind.
Is there any recomendation when to submit to drivers/staging instead of drivers? I've searched the archives but haven't found an answer to it. If you can instead just point me to a document I'm fine.
I believe Documentation/development-process/2.Process gives the best description of what staging is for:
<quote> 2.4.1: STAGING TREES
The kernel source tree contains the drivers/staging/ directory, where many sub-directories for drivers or filesystems that are on their way to being added to the kernel tree live. They remain in drivers/staging while they still need more work; once complete, they can be moved into the kernel proper. This is a way to keep track of drivers that aren't up to Linux kernel coding or quality standards, but people may want to use them and track development.
Greg Kroah-Hartman currently maintains the staging tree. Drivers that still need work are sent to him, with each driver having its own subdirectory in drivers/staging/. Along with the driver source files, a TODO file should be present in the directory as well. The TODO file lists the pending work that the driver needs for acceptance into the kernel proper, as well as a list of people that should be Cc'd for any patches to the driver. Current rules require that drivers contributed to staging must, at a minimum, compile properly.
Staging can be a relatively easy way to get new drivers into the mainline where, with luck, they will come to the attention of other developers and improve quickly. Entry into staging is not the end of the story, though; code in staging which is not seeing regular progress will eventually be removed. Distributors also tend to be relatively reluctant to enable staging drivers. So staging is, at best, a stop on the way toward becoming a proper mainline driver. </quote>
The driver(s) in question is a bus driver for multi function FPGAs made by my company and one first iio/adc driver using this bus. It was sucessfully tested on x86 but is known to crash on powerpc because of my parser code (which will of cause be fixed when submitting, even into staging).
If it is a new class of driver then I guess that means that you will define some new APIs. Which is all the more reason to get it directly into mainline. You cannot extend or define any kernel interfaces from staging.
Bjørn
Thanks for the answer Bjørn. I wrote the driver to be submittable into mainline and defined a new API, so I'll send directly to lkml when it has a good stable point (hopefully the next 1-2 Weeks). Thanks Johannes