Re: [PATCH 2/2] pwm: Enable compile testing for some of drivers

[Krzysztof Kozlowski <krzk@kernel.org>]

On Tue, Jan 07, 2020 at 08:26:45AM +0100, Uwe Kleine-König wrote:
> Hello Krzysztof,
> 
> On Mon, Dec 30, 2019 at 06:21:13PM +0100, Krzysztof Kozlowski wrote:
> > Some of the PWM drivers can be compile tested to increase build
> > coverage.
> > 
> > The Meson PWM driver requires COMMON_CLK dependency.
> 
> I'm surprised that there are not more that need this. Is HAVE_CLK not
> enough?

Nope. E.g. for alpha architecture, HAVE_CLK is not set and without
COMMON_CLK:

drivers/pwm/pwm-meson.o: In function `meson_pwm_init_channels':
(.text+0x244): undefined reference to `devm_clk_register'

I guess other solution would be to add stubs for few clk functions...

> Also HAS_IOMEM is a typical requirement, but I tested with an ARCH=um
> config (which does't have HAS_IOMEM) and they all compile fine.

Because of !HAS_IOMEM, since some time ARCH=um does not support
COMPILE_TEST. Therefore HAS_IOMEM dependency is not needed for compile
testing (and for regular build it is selected by ARCH).

> 
> > @@ -318,7 +319,7 @@ config PWM_MEDIATEK
> >  
> >  config PWM_MXS
> >  	tristate "Freescale MXS PWM support"
> > -	depends on ARCH_MXS && OF
> > +	depends on (ARCH_MXS && OF) || COMPILE_TEST
> >  	select STMP_DEVICE
> >  	help
> >  	  Generic PWM framework driver for Freescale MXS.
> > @@ -328,7 +329,8 @@ config PWM_MXS
> >  
> >  config PWM_OMAP_DMTIMER
> >  	tristate "OMAP Dual-Mode Timer PWM support"
> > -	depends on OF && ARCH_OMAP && OMAP_DM_TIMER
> > +	depends on (ARCH_OMAP && OMAP_DM_TIMER) || COMPILE_TEST
> > +	depends on OF
> 
> I'm surprised that OF isn't required for PWM_MXS but is is for
> PWM_OMAP_DMTIMER. pwm-mxs compiles without CONFIG_OF, didn't test
> pwm-omap-dmtimer.

Since some time !OF has all necessary stubs so OF is actually needed
only for binding, not compiling.

Best regards,
Krzysztof