metag: init common clk and use "core" clk

If the common clock framework is enabled, call of_clk_init(NULL) in
time_init() to register device tree clocks with the clock framework.

After this time_init() calls a new function init_metag_clocks(), which
looks for a clock named "core" in the node compatible with "img,meta"
(usually the root node). If found the get_core_freq machine callback is
overridden to obtain the core clock frequency using that clock.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Mike Turquette <mturquette@linaro.org>
Cc: Grant Likely <grant.likely@linaro.org>
Cc: Rob Herring <rob.herring@calxeda.com>
Cc: devicetree-discuss@lists.ozlabs.org

1 files changed, 8 insertions, 0 deletions

diff --git a/arch/metag/include/asm/clock.h b/arch/metag/include/asm/clock.h
index 3e2915a280c7..ded4ab2e1fd0 100644
--- a/arch/metag/include/asm/clock.h
+++ b/arch/metag/include/asm/clock.h
@@ -19,6 +19,8 @@
  *			core frequency will be determined like this:
  *			Meta 1: based on loops_per_jiffy.
  *			Meta 2: (EXPAND_TIMER_DIV + 1) MHz.
+ *			If a "core" clock is provided by the device tree, it
+ *			will override this function.
  */
 struct meta_clock_desc {
 	unsigned long		(*get_core_freq)(void);
@@ -27,6 +29,12 @@ struct meta_clock_desc {
 extern struct meta_clock_desc _meta_clock;
 
 /*
+ * Perform platform clock initialisation, reading clocks from device tree etc.
+ * Only accessible during boot.
+ */
+void init_metag_clocks(void);
+
+/*
  * Set up the default clock, ensuring all callbacks are valid - only accessible
  * during boot.
  */