Re: [PATCH] clocksource/drivers/sp804: make CONFIG_ARM_TIMER_SP804 selectable again

[Thomas Gleixner]

Helmut,

On Fri, 16 Aug 2019, Helmut Grohne wrote:
> I also note that there are likely more instances for this pattern.
> Should they be fixed in a similar way? You can find a lot using the
> following incantation:
> 
> $ git describe --tags
> v5.3-rc4
> $ git ls-files -- "*/Kconfig" | xargs git grep --cached 'bool .* if 
> COMPILE_TEST$' -- | wc -l
> 185
> $
> 
> Seems like an anti-pattern to me. It is particularly common in the
> clocksource subtree.

After some rumaging I figured out that the idea behind this is that the
platforms which need those clocksources use 'select $CLOCKSOURCE' which
works despite the 'if COMPILE_TEST'.

The 'if COMPILE_TEST' is there to hide the config option when there is no
platform which needs it and expose it for compile test purposes.

So if your particular platform does not use 'select ARM_TIMER_SP804' then
the right fix is to add it to that platform.

Thanks,

tglx

[PATCH] clocksource/drivers/sp804: make CONFIG_ARM_TIMER_SP804 selectable again

[Helmut Grohne]

Adding a dependency on CONFIG_COMPILE_TEST makes the relevant item
unselectable for practical purposes. The correct solution is to add a
dependency alternative on the relevant architecture.

Fixes: dfc82faad72520 ("clocksource/drivers/sp804: Add COMPILE_TEST to 
CONFIG_ARM_TIMER_SP804")
Link: https://lore.kernel.org/lkml/20190618120719.a4kgyiuljm5uivfq@laureti-dev/
Link: 
https://lore.kernel.org/lkml/alpine.deb.2.21.1908152227590.1...@nanos.tec.linutronix.de/
Signed-off-by: Helmut Grohne 
---
 drivers/clocksource/Kconfig | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

Hi Thomas,

On Thu, Aug 15, 2019 at 10:30:39PM +0200, Thomas Gleixner wrote:
> The obvious fix is to add
> 
>   depends on ARM || ARM64 || COMPILE_TEST
> 
> instead of reverting the whole thing. Care to do that?

Incidentally, that's what I proposed earlier as RFC. Resending that
variant now.

I also note that there are likely more instances for this pattern.
Should they be fixed in a similar way? You can find a lot using the
following incantation:

$ git describe --tags
v5.3-rc4
$ git ls-files -- "*/Kconfig" | xargs git grep --cached 'bool .* if 
COMPILE_TEST$' -- | wc -l
185
$

Seems like an anti-pattern to me. It is particularly common in the
clocksource subtree.

Helmut

diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig
index 5e9317dc3d39..7081a250573b 100644
--- a/drivers/clocksource/Kconfig
+++ b/drivers/clocksource/Kconfig
@@ -393,7 +393,8 @@ config ARM_GLOBAL_TIMER
  This options enables support for the ARM global timer unit
 
 config ARM_TIMER_SP804
-   bool "Support for Dual Timer SP804 module" if COMPILE_TEST
+   bool "Support for Dual Timer SP804 module"
+   depends on ARM || ARM64 || COMPILE_TEST
depends on GENERIC_SCHED_CLOCK && CLKDEV_LOOKUP
select CLKSRC_MMIO
select TIMER_OF if OF
-- 
2.11.0