add HAVE_CLK to Kconfig, for driver dependencies

Flag platforms as HAVE_CLK (or not) in Kconfig, based on whether they
support <linux/clk.h> calls, so that otherwise portable drivers which need
those calls can list that dependency.

Something like this is a prerequisite for merging the musb_hdrc driver,
currently used on platforms including Davinci, OMAP2430, OMAP3xx ...  and
the discrete TUSB6010 chip, which doesn't have a natural platform
dependency.  (Used with OMAP 2420 in current Nokia N8x0 tablets.)

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Cc: Russell King <rmk@arm.linux.org.uk>
Acked-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Paul Mundt <lethal@linux-sh.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 7 insertions, 0 deletions

diff --git a/arch/Kconfig b/arch/Kconfig
index ad89a33d8c6..4d5ebbc1e72 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -42,3 +42,10 @@ config HAVE_DMA_ATTRS
 
 config USE_GENERIC_SMP_HELPERS
         def_bool n
+
+config HAVE_CLK
+        def_bool n
+        help
+          The <linux/clk.h> calls support software clock gating and
+          thus are a key power management tool on many systems.
+