From mboxrd@z Thu Jan  1 00:00:00 1970
From: atull <atull@opensource.altera.com>
Subject: Re: [PATCH v18 6/6] ARM: socfpga: fpga bridge driver support
Date: Thu, 22 Sep 2016 14:53:34 -0500
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To: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Mark Rutland <mark.rutland@arm.com>, Moritz Fischer <moritz.fischer@ettus.com>, Ian Campbell <ijc+devicetree@hellion.org.uk>, Matthew Gerlach <mgerlach@altera.com>, Greg Kroah-Hartman <gregkh@linuxfoundation.org>, LKML <linux-kernel@vger.kernel.org>, Devicetree List <devicetree@vger.kernel.org>, Rob Herring <robh+dt@kernel.org>, Dinh Nguyen <dinguyen@opensource.altera.com>, Alan Tull <delicious.quinoa@gmail.com>, "linux-arm-kernel@lists.infradead.org" <linux-arm-kernel@lists.infradead.org>
List-Id: devicetree@vger.kernel.org

On Tue, 9 Aug 2016, Paul Gortmaker wrote:

> [Re: [PATCH v18 6/6] ARM: socfpga: fpga bridge driver support] On 08/08/2016 (Mon 13:44) Moritz Fischer wrote:
> 
> > Hi Alan,
> > 
> > On Mon, Aug 8, 2016 at 12:18 PM, atull <atull@opensource.altera.com> wrote:
> > 
> > >> Please don't use module.h in drivers controlled by a bool
> > >> Kconfig setting.
> > >>
> > >> THanks,
> > >> Paul.
> > >>
> > >
> > > Thanks for the feedback.  Can you provide an example of what you
> > > would consider to be proper usage in the kernel?
> > 
> > 
> > I think Paul is suggesting to use
> > 
> > static int __init alt_fpga_bridge_init(void)
> > {
> >         platform_driver_register(&alt_fpga_bridge_driver);
> > }
> > 
> > device_initcall(alt_fpga_bridge_init);
> > 
> > or better:
> > 
> > builtin_platform_driver(&alt_fpga_bridge_driver);
> > 
> > Like for example in: drivers/cpuidle/cpuidle-mvebu-v7.c
> 
> Yes, pretty much that -- if you have a bool Kconfig, you should be using
> builtin registration functions, and have no need for module.h or
> anything MODULE_<xyz> or any module_init/module_exit calls.
> 
> An empty file containing nothing but #include <linux/module.h> will
> cause cpp to emit about 750k of goop, so we really should only be using
> it for drivers that are genuinely modular; i.e. tristate Kconfig.
> 
> Thanks,
> Paul.
> --
> 
> > 
> > Cheers,
> > 
> > Moritz
> 

Thanks for the feedback and explanations!

I've retested my stuff with it all built as modules (mgr, bridged,
and fpga-region) and it all works that way as well as built in.
So I'll fix up the Kconfig as tristates for everybody.  Also
I'll add some dependencies as FPGA_REGION should be dependent
on FPGA_BRIDGE.

Alan