Re: [PATCH] watchdog: dw_wdt: remove build dependencies

[Baruch Siach <baruch@tkos.co.il>]

Hi Wim,

On Mon, Dec 30, 2013 at 12:03:36PM +0100, Wim Van Sebroeck wrote:
> > > If this is ARM hardware, then this should have the dependency "depends 
> > > on ARM".
> > > Only if other architectures start using this watchdog device, then the 
> > > "depends on ARM" can go.
> > 
> > Well, we intend to use this driver on Xtensa platform, does this count?
> 
> Xtensa is indeed another Platform, but then I expect the patch to:
> 1) make this clear in the Kconfig file

OK. So should I add a dependency on CONFIG_XTENSA, or just add a comment 
saying that this driver is cross platform.

> 2) have a commit-message that also explains this.

Will do.

> 
> > As a general rule wouldn't it be better to have the widest possible build 
> > coverage, and encourage arch neutral driver coding?
> 
> We try to have as much arch neutral driver encoding (see the Kconfig & 
> Makefile in the drivers/watchdog directory and you will see that we have 
> drivers that are not depending on a specific hardware architecture), but we 
> should not forget that certain hardware is only available in a certain 
> architecture and that it thus does not make any sense to compile kernels 
> with drivers that never will be used. So the general rule still is: use 
> common sense and look at the broader picture.

This watchdog is part of the DesignWare family of IP blocks. These IP block 
are being reused on many platforms. The kernel already has drivers for 
DesignWare SPI, I2C, USB, and hopefully also GPIO soon. None of these drivers 
depend on any specific architecture. IMO it makes sense to drop arch 
dependency entirely in this case.

baruch

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