clk: ti: add support for TI fixed factor clock

This behaves exactly in similar manner to basic fixed-factor-clock, but
adds a few properties on top for handling clock hardware autoidling.
Signed-off-by: NTero Kristo <t-kristo@ti.com>
Acked-by: NTony Lindgren <tony@atomide.com>
Signed-off-by: NMike Turquette <mturquette@linaro.org>

Documentation/devicetree/bindings/clock/ti/fixed-factor-clock.txt

+Binding for TI fixed factor rate clock sources.
+
+Binding status: Unstable - ABI compatibility may be broken in the future
+
+This binding uses the common clock binding[1], and also uses the autoidle
+support from TI autoidle clock [2].
+
+[1] Documentation/devicetree/bindings/clock/clock-bindings.txt
+[2] Documentation/devicetree/bindings/clock/ti/autoidle.txt
+
+Required properties:
+- compatible : shall be "ti,fixed-factor-clock".
+- #clock-cells : from common clock binding; shall be set to 0.
+- ti,clock-div: fixed divider.
+- ti,clock-mult: fixed multiplier.
+- clocks: parent clock.
+
+Optional properties:
+- ti,autoidle-shift: bit shift of the autoidle enable bit for the clock,
+  see [2]
+- reg: offset for the autoidle register of this 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
+
+Example:
+	clock {
+		compatible = "ti,fixed-factor-clock";
+		clocks = <&parentclk>;
+		#clock-cells = <0>;
+		ti,clock-div = <2>;
+		ti,clock-mult = <1>;
+	};
+
+	dpll_usb_clkdcoldo_ck: dpll_usb_clkdcoldo_ck {
+		#clock-cells = <0>;
+		compatible = "ti,fixed-factor-clock";
+		clocks = <&dpll_usb_ck>;
+		ti,clock-div = <1>;
+		ti,autoidle-shift = <8>;
+		reg = <0x01b4>;
+		ti,clock-mult = <1>;
+		ti,invert-autoidle-bit;
+	};

drivers/clk/ti/Makefile

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

drivers/clk/ti/fixed-factor.c

+/*
+ * TI Fixed Factor Clock
+ *
+ * Copyright (C) 2013 Texas Instruments, Inc.
+ *
+ * Tero Kristo <t-kristo@ti.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed "as is" WITHOUT ANY WARRANTY of any
+ * kind, whether express or implied; without even the implied warranty
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/clk-provider.h>
+#include <linux/slab.h>
+#include <linux/err.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/clk/ti.h>
+
+#undef pr_fmt
+#define pr_fmt(fmt) "%s: " fmt, __func__
+
+/**
+ * of_ti_fixed_factor_clk_setup - Setup function for TI fixed factor clock
+ * @node: device node for this clock
+ *
+ * Sets up a simple fixed factor clock based on device tree info.
+ */
+static void __init of_ti_fixed_factor_clk_setup(struct device_node *node)
+{
+	struct clk *clk;
+	const char *clk_name = node->name;
+	const char *parent_name;
+	u32 div, mult;
+	u32 flags = 0;
+
+	if (of_property_read_u32(node, "ti,clock-div", &div)) {
+		pr_err("%s must have a clock-div property\n", node->name);
+		return;
+	}
+
+	if (of_property_read_u32(node, "ti,clock-mult", &mult)) {
+		pr_err("%s must have a clock-mult property\n", node->name);
+		return;
+	}
+
+	if (of_property_read_bool(node, "ti,set-rate-parent"))
+		flags |= CLK_SET_RATE_PARENT;
+
+	parent_name = of_clk_get_parent_name(node, 0);
+
+	clk = clk_register_fixed_factor(NULL, clk_name, parent_name, flags,
+					mult, div);
+
+	if (!IS_ERR(clk)) {
+		of_clk_add_provider(node, of_clk_src_simple_get, clk);
+		of_ti_clk_autoidle_setup(node);
+	}
+}
+CLK_OF_DECLARE(ti_fixed_factor_clk, "ti,fixed-factor-clock",
+	       of_ti_fixed_factor_clk_setup);