clk: add CS2000 Fractional-N driver

This patch adds CS2000 Fractional-N driver as clock provider.
Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
[sboyd@codeaurora.org: Fix unsigned checked for < 0 in
cs2000_ratio_get()]
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>

Documentation/devicetree/bindings/clock/cs2000-cp.txt

+CIRRUS LOGIC Fractional-N Clock Synthesizer & Clock Multiplier
+
+Required properties:
+
+- compatible:		"cirrus,cs2000-cp"
+- reg:			The chip select number on the I2C bus
+- clocks:		common clock binding for CLK_IN, XTI/REF_CLK
+- clock-names:		CLK_IN : clk_in, XTI/REF_CLK : ref_clk
+- #clock-cells:		must be <0>
+
+Example:
+
+&i2c2 {
+	...
+	cs2000: clk_multiplier@4f {
+		#clock-cells = <0>;
+		compatible = "cirrus,cs2000-cp";
+		reg = <0x4f>;
+		clocks = <&rcar_sound 0>, <&x12_clk>;
+		clock-names = "clk_in", "ref_clk";
+	};
+};

drivers/clk/Kconfig

@@ -116,6 +116,12 @@ config COMMON_CLK_CDCE925
 	  Given a target output frequency, the driver will set the PLL and
 	  divider to best approximate the desired output.
 
+config COMMON_CLK_CS2000_CP
+	tristate "Clock driver for CS2000 Fractional-N Clock Synthesizer & Clock Multiplier"
+	depends on I2C
+	help
+	  If you say yes here you get support for the CS2000 clock multiplier.
+
 config COMMON_CLK_S2MPS11
 	tristate "Clock driver for S2MPS1X/S5M8767 MFD"
 	depends on MFD_SEC_CORE

drivers/clk/Makefile

@@ -21,6 +21,7 @@ obj-$(CONFIG_MACH_ASM9260)		+= clk-asm9260.o
 obj-$(CONFIG_COMMON_CLK_AXI_CLKGEN)	+= clk-axi-clkgen.o
 obj-$(CONFIG_ARCH_AXXIA)		+= clk-axm5516.o
 obj-$(CONFIG_COMMON_CLK_CDCE706)	+= clk-cdce706.o
+obj-$(CONFIG_COMMON_CLK_CS2000_CP)	+= clk-cs2000-cp.o
 obj-$(CONFIG_ARCH_CLPS711X)		+= clk-clps711x.o
 obj-$(CONFIG_ARCH_EFM32)		+= clk-efm32gg.o
 obj-$(CONFIG_ARCH_HIGHBANK)		+= clk-highbank.o