clk: add device tree fixed-factor-clock binding support

Binding for simple fixed factor rate clock sources.

This binding uses the common clock binding[1].

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

Required properties:

- compatible : shall be "fixed-factor-clock".

- #clock-cells : from common clock binding; shall be set to 0.

- clock-div: fixed divider.

- clock-mult: fixed multiplier.

- clocks: parent clock.

Optional properties:

- clock-output-names : From common clock binding.

Example:

	clock {

		compatible = "fixed-factor-clock";

		clocks = <&parentclk>;

		#clock-cells = <0>;

		div = <2>;

		mult = <1>;

	};

#include <linux/clk-provider.h>

#include <linux/slab.h>

#include <linux/err.h>

#include <linux/of.h>

/*

 * DOC: basic fixed multiplier and divider clock that cannot gate

	return clk;

}

#ifdef CONFIG_OF

/**

 * of_fixed_factor_clk_setup() - Setup function for simple fixed factor clock

 */

void __init of_fixed_factor_clk_setup(struct device_node *node)

{

	struct clk *clk;

	const char *clk_name = node->name;

	const char *parent_name;

	u32 div, mult;

	if (of_property_read_u32(node, "clock-div", &div)) {

		pr_err("%s Fixed factor clock <%s> must have a clock-div property\n",

			__func__, node->name);

		return;

	}

	if (of_property_read_u32(node, "clock-mult", &mult)) {

		pr_err("%s Fixed factor clock <%s> must have a clokc-mult property\n",

			__func__, node->name);

		return;

	}

	of_property_read_string(node, "clock-output-names", &clk_name);

	parent_name = of_clk_get_parent_name(node, 0);

	clk = clk_register_fixed_factor(NULL, clk_name, parent_name, 0,

					mult, div);

	if (!IS_ERR(clk))

		of_clk_add_provider(node, of_clk_src_simple_get, clk);

}

EXPORT_SYMBOL_GPL(of_fixed_factor_clk_setup);

CLK_OF_DECLARE(fixed_factor_clk, "fixed-factor-clock",

		of_fixed_factor_clk_setup);

#endif

		void __iomem *reg, u8 shift, u32 mask,

		u8 clk_mux_flags, u32 *table, spinlock_t *lock);

void of_fixed_factor_clk_setup(struct device_node *node);

/**

 * struct clk_fixed_factor - fixed multiplier and divider clock

 *