CLK: ti: add support for ti divider-clock

This patch adds support for TI divider clock binding, which simply uses
the basic clock divider to provide the features needed.
Signed-off-by: Tero Kristo <t-kristo@ti.com>
Acked-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Mike Turquette <mturquette@linaro.org>

Documentation/devicetree/bindings/clock/ti/divider.txt

+Binding for TI divider clock
+
+Binding status: Unstable - ABI compatibility may be broken in the future
+
+This binding uses the common clock binding[1].  It assumes a
+register-mapped adjustable clock rate divider that does not gate and has
+only one input clock or parent.  By default the value programmed into
+the register is one less than the actual divisor value.  E.g:
+
+register value		actual divisor value
+0			1
+1			2
+2			3
+
+This assumption may be modified by the following optional properties:
+
+ti,index-starts-at-one - valid divisor values start at 1, not the default
+of 0.  E.g:
+register value		actual divisor value
+1			1
+2			2
+3			3
+
+ti,index-power-of-two - valid divisor values are powers of two.  E.g:
+register value		actual divisor value
+0			1
+1			2
+2			4
+
+Additionally an array of valid dividers may be supplied like so:
+
+	ti,dividers = <4>, <8>, <0>, <16>;
+
+Which will map the resulting values to a divisor table by their index:
+register value		actual divisor value
+0			4
+1			8
+2			<invalid divisor, skipped>
+3			16
+
+Any zero value in this array means the corresponding bit-value is invalid
+and must not be used.
+
+The binding must also provide the register to control the divider and
+unless the divider array is provided, min and max dividers. Optionally
+the number of bits to shift that mask, if necessary. If the shift value
+is missing it is the same as supplying a zero shift.
+
+This binding can also optionally provide support to the hardware autoidle
+feature, see [2].
+
+[1] Documentation/devicetree/bindings/clock/clock-bindings.txt
+[2] Documentation/devicetree/bindings/clock/ti/autoidle.txt
+
+Required properties:
+- compatible : shall be "ti,divider-clock" or "ti,composite-divider-clock".
+- #clock-cells : from common clock binding; shall be set to 0.
+- clocks : link to phandle of parent clock
+- reg : offset for register controlling adjustable divider
+
+Optional properties:
+- clock-output-names : from common clock binding.
+- ti,dividers : array of integers defining divisors
+- ti,bit-shift : number of bits to shift the divider value, defaults to 0
+- ti,min-div : min divisor for dividing the input clock rate, only
+  needed if the first divisor is offset from the default value (1)
+- ti,max-div : max divisor for dividing the input clock rate, only needed
+  if ti,dividers is not defined.
+- ti,index-starts-at-one : valid divisor programming starts at 1, not zero,
+  only valid if ti,dividers is not defined.
+- ti,index-power-of-two : valid divisor programming must be a power of two,
+  only valid if ti,dividers is not defined.
+- ti,autoidle-shift : bit shift of the autoidle enable bit for the clock,
+  see [2]
+- ti,invert-autoidle-bit : autoidle is enabled by setting the bit to 0,
+  see [2]
+- ti,set-rate-parent : clk_set_rate is propagated to parent
+
+Examples:
+dpll_usb_m2_ck: dpll_usb_m2_ck@4a008190 {
+	#clock-cells = <0>;
+	compatible = "ti,divider-clock";
+	clocks = <&dpll_usb_ck>;
+	ti,max-div = <127>;
+	reg = <0x190>;
+	ti,index-starts-at-one;
+};
+
+aess_fclk: aess_fclk@4a004528 {
+	#clock-cells = <0>;
+	compatible = "ti,divider-clock";
+	clocks = <&abe_clk>;
+	ti,bit-shift = <24>;
+	reg = <0x528>;
+	ti,max-div = <2>;
+};
+
+dpll_core_m3x2_div_ck: dpll_core_m3x2_div_ck {
+	#clock-cells = <0>;
+	compatible = "ti,composite-divider-clock";
+	clocks = <&dpll_core_x2_ck>;
+	ti,max-div = <31>;
+	reg = <0x0134>;
+	ti,index-starts-at-one;
+};
+
+ssi_ssr_div_fck_3430es2: ssi_ssr_div_fck_3430es2 {
+	#clock-cells = <0>;
+	compatible = "ti,composite-divider-clock";
+	clocks = <&corex2_fck>;
+	ti,bit-shift = <8>;
+	reg = <0x0a40>;
+	ti,dividers = <0>, <1>, <2>, <3>, <4>, <0>, <6>, <0>, <8>;
+};

drivers/clk/ti/Makefile

 ifneq ($(CONFIG_OF),)
 obj-y					+= clk.o autoidle.o
-clk-common				= dpll.o composite.o
+clk-common				= dpll.o composite.o divider.o
 endif

drivers/clk/ti/composite.c

@@ -31,7 +31,7 @@
 static unsigned long ti_composite_recalc_rate(struct clk_hw *hw,
 					      unsigned long parent_rate)
 {
-	return clk_divider_ops.recalc_rate(hw, parent_rate);
+	return ti_clk_divider_ops.recalc_rate(hw, parent_rate);
 }
 
 static long ti_composite_round_rate(struct clk_hw *hw, unsigned long rate,

include/linux/clk/ti.h

@@ -223,6 +223,8 @@ struct ti_clk_ll_ops {
 
 extern struct ti_clk_ll_ops *ti_clk_ll_ops;
 
+extern const struct clk_ops ti_clk_divider_ops;
+
 #define to_clk_hw_omap(_hw) container_of(_hw, struct clk_hw_omap, hw)
 
 void omap2_init_clk_hw_omap_clocks(struct clk *clk);