clk: introduce the common clock framework

The common clock framework defines a common struct clk useful across
most platforms as well as an implementation of the clk api that drivers
can use safely for managing clocks.

The net result is consolidation of many different struct clk definitions
and platform-specific clock framework implementations.

This patch introduces the common struct clk, struct clk_ops and an
implementation of the well-known clock api in include/clk/clk.h.
Platforms may define their own hardware-specific clock structure and
their own clock operation callbacks, so long as it wraps an instance of
struct clk_hw.

See Documentation/clk.txt for more details.

This patch is based on the work of Jeremy Kerr, which in turn was based
on the work of Ben Herrenschmidt.

Signed-off-by: Mike Turquette <[email protected]>
Signed-off-by: Mike Turquette <[email protected]>
Reviewed-by: Thomas Gleixner <[email protected]>
Tested-by: Andrew Lunn <[email protected]>
Reviewed-by: Rob Herring <rob.herring <at> calxeda.com>
Cc: Russell King <[email protected]>
Cc: Jeremy Kerr <[email protected]>
Cc: Arnd Bergman <[email protected]>
Cc: Paul Walmsley <[email protected]>
Cc: Shawn Guo <[email protected]>
Cc: Sascha Hauer <[email protected]>
Cc: Richard Zhao <[email protected]>
Cc: Saravana Kannan <[email protected]>
Cc: Magnus Damm <[email protected]>
Cc: Mark Brown <[email protected]>
Cc: Linus Walleij <[email protected]>
Cc: Stephen Boyd <[email protected]>
Cc: Amit Kucheria <[email protected]>
Cc: Deepak Saxena <[email protected]>
Cc: Grant Likely <[email protected]>
Signed-off-by: Arnd Bergmann <[email protected]>

drivers/clk/Kconfig

@@ -8,3 +8,43 @@ config HAVE_CLK_PREPARE
 
 config HAVE_MACH_CLKDEV
 	bool
+
+menuconfig COMMON_CLK
+	bool "Common Clock Framework"
+	select HAVE_CLK_PREPARE
+	---help---
+	  The common clock framework is a single definition of struct
+	  clk, useful across many platforms, as well as an
+	  implementation of the clock API in include/linux/clk.h.
+	  Architectures utilizing the common struct clk should select
+	  this automatically, but it may be necessary to manually select
+	  this option for loadable modules requiring the common clock
+	  framework.
+
+	  If in doubt, say "N".
+
+if COMMON_CLK
+
+config COMMON_CLK_DISABLE_UNUSED
+	bool "Disabled unused clocks at boot"
+	depends on COMMON_CLK
+	---help---
+	  Traverses the entire clock tree and disables any clocks that are
+	  enabled in hardware but have not been enabled by any device drivers.
+	  This saves power and keeps the software model of the clock in line
+	  with reality.
+
+	  If in doubt, say "N".
+
+config COMMON_CLK_DEBUG
+	bool "DebugFS representation of clock tree"
+	depends on COMMON_CLK
+	select DEBUG_FS
+	---help---
+	  Creates a directory hierchy in debugfs for visualizing the clk
+	  tree structure.  Each directory contains read-only members
+	  that export information specific to that clk node: clk_rate,
+	  clk_flags, clk_prepare_count, clk_enable_count &
+	  clk_notifier_count.
+
+endif

drivers/clk/Makefile

@@ -1,2 +1,3 @@
 
 obj-$(CONFIG_CLKDEV_LOOKUP)	+= clkdev.o
+obj-$(CONFIG_COMMON_CLK)	+= clk.o