clk: samsung: Add clock driver for S5PV210 and compatible SoCs

* Samsung S5P6442/S5PC110/S5PV210 Clock Controller

Samsung S5P6442, S5PC110 and S5PV210 SoCs contain integrated clock

controller, which generates and supplies clock to various controllers

within the SoC.

Required Properties:

- compatible: should be one of following:

	- "samsung,s5pv210-clock" : for clock controller of Samsung

	  S5PC110/S5PV210 SoCs,

	- "samsung,s5p6442-clock" : for clock controller of Samsung

	  S5P6442 SoC.

- reg: physical base address of the controller and length of memory mapped

  region.

- #clock-cells: should be 1.

All available clocks are defined as preprocessor macros in

dt-bindings/clock/s5pv210.h header and can be used in device tree sources.

External clocks:

There are several clocks that are generated outside the SoC. It is expected

that they are defined using standard clock bindings with following

clock-output-names:

 - "xxti": external crystal oscillator connected to XXTI and XXTO pins of

the SoC,

 - "xusbxti": external crystal oscillator connected to XUSBXTI and XUSBXTO

pins of the SoC,

A subset of above clocks available on given board shall be specified in

board device tree, including the system base clock, as selected by XOM[0]

pin of the SoC. Refer to generic fixed rate clock bindings

documentation[1] for more information how to specify these clocks.

[1] Documentation/devicetree/bindings/clock/fixed-clock.txt

Example: Clock controller node:

	clock: clock-controller@7e00f000 {

		compatible = "samsung,s5pv210-clock";

		reg = <0x7e00f000 0x1000>;

		#clock-cells = <1>;

	};

Example: Required external clocks:

	xxti: clock-xxti {

		compatible = "fixed-clock";

		clock-output-names = "xxti";

		clock-frequency = <24000000>;

		#clock-cells = <0>;

	};

	xusbxti: clock-xusbxti {

		compatible = "fixed-clock";

		clock-output-names = "xusbxti";

		clock-frequency = <24000000>;

		#clock-cells = <0>;

	};

Example: UART controller node that consumes the clock generated by the clock

  controller (refer to the standard clock bindings for information about

  "clocks" and "clock-names" properties):

	uart0: serial@e2900000 {

		compatible = "samsung,s5pv210-uart";

		reg = <0xe2900000 0x400>;

		interrupt-parent = <&vic1>;

		interrupts = <10>;

		clock-names = "uart", "clk_uart_baud0",

				"clk_uart_baud1";

		clocks = <&clocks UART0>, <&clocks UART0>,

				<&clocks SCLK_UART0>;

		status = "disabled";

	};

obj-$(CONFIG_S3C2412_COMMON_CLK)+= clk-s3c2412.o

obj-$(CONFIG_S3C2443_COMMON_CLK)+= clk-s3c2443.o

obj-$(CONFIG_ARCH_S3C64XX)	+= clk-s3c64xx.o

obj-$(CONFIG_ARCH_S5PV210)	+= clk-s5pv210.o