sh: clkfwk: Add a helper for rate rounding by divisor ranges.

This adds a new clk_rate_div_range_round() for implementing rate rounding
by divisor ranges. This can be used trivially by clocks that support
arbitrary ranged divisors without the need for rate table construction.

This should only be used by clocks that both have large divisor ranges in
addition to clocks that will never be arbitrarily scaled, as the lack of
a backing frequency table will prevent cpufreq from being able to do much
of anything with them.

Primarily intended for use as a ->recalc helper.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>
diff --git a/include/linux/sh_clk.h b/include/linux/sh_clk.h
index 49f6e9b..4dca992 100644
--- a/include/linux/sh_clk.h
+++ b/include/linux/sh_clk.h
@@ -119,6 +119,9 @@
 			struct cpufreq_frequency_table *freq_table,
 			unsigned long rate);
 
+long clk_rate_div_range_round(struct clk *clk, unsigned int div_min,
+			      unsigned int div_max, unsigned long rate);
+
 #define SH_CLK_MSTP32(_parent, _enable_reg, _enable_bit, _flags)	\
 {									\
 	.parent		= _parent,					\