clk: divider: Make generic for usage elsewhere

Some devices don't use mmio to interact with dividers. Split out the
logic from the register read/write parts so that we can reuse the
division logic elsewhere.
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Tested-by: Kenneth Westfield <kwestfie@codeaurora.org>
Signed-off-by: Michael Turquette <mturquette@linaro.org>

include/linux/clk-provider.h

@@ -353,6 +353,17 @@ struct clk_divider {
 #define CLK_DIVIDER_READ_ONLY		BIT(5)
 
 extern const struct clk_ops clk_divider_ops;
+
+unsigned long divider_recalc_rate(struct clk_hw *hw, unsigned long parent_rate,
+		unsigned int val, const struct clk_div_table *table,
+		unsigned long flags);
+long divider_round_rate(struct clk_hw *hw, unsigned long rate,
+		unsigned long *prate, const struct clk_div_table *table,
+		u8 width, unsigned long flags);
+int divider_get_val(unsigned long rate, unsigned long parent_rate,
+		const struct clk_div_table *table, u8 width,
+		unsigned long flags);
+
 struct clk *clk_register_divider(struct device *dev, const char *name,
 		const char *parent_name, unsigned long flags,
 		void __iomem *reg, u8 shift, u8 width,