[PATCHv9 08/43] clk: ti: add composite clock support

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This is a multipurpose clock node, which contains support for multiple
sub-clocks. Uses basic composite clock type to implement the actual
functionality, and TI specific gate, mux and divider clocks.

Signed-off-by: Tero Kristo <t-kristo@xxxxxx>
---
 .../devicetree/bindings/clock/ti/composite.txt     |   54 +++++
 drivers/clk/ti/Makefile                            |    2 +-
 drivers/clk/ti/composite.c                         |  222 ++++++++++++++++++++
 include/linux/clk/ti.h                             |    8 +
 4 files changed, 285 insertions(+), 1 deletion(-)
 create mode 100644 Documentation/devicetree/bindings/clock/ti/composite.txt
 create mode 100644 drivers/clk/ti/composite.c

diff --git a/Documentation/devicetree/bindings/clock/ti/composite.txt b/Documentation/devicetree/bindings/clock/ti/composite.txt
new file mode 100644
index 0000000..5f43c47
--- /dev/null
+++ b/Documentation/devicetree/bindings/clock/ti/composite.txt
@@ -0,0 +1,54 @@
+Binding for TI composite 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 composite clock with multiple different sub-types;
+
+a multiplexer clock with multiple input clock signals or parents, one
+of which can be selected as output, this behaves exactly as [2]
+
+an adjustable clock rate divider, this behaves exactly as [3]
+
+a gating function which can be used to enable and disable the output
+clock, this behaves exactly as [4]
+
+The binding must provide a list of the component clocks that shall be
+merged to this clock. The component clocks shall be of one of the
+"ti,*composite*-clock" types.
+
+[1] Documentation/devicetree/bindings/clock/clock-bindings.txt
+[2] Documentation/devicetree/bindings/clock/ti/mux.txt
+[3] Documentation/devicetree/bindings/clock/ti/divider.txt
+[4] Documentation/devicetree/bindings/clock/ti/gate.txt
+
+Required properties:
+- compatible : shall be: "ti,composite-clock"
+- clocks : link phandles of component clocks
+- #clock-cells : from common clock binding; shall be set to 0.
+
+Examples:
+
+usb_l4_gate_ick: usb_l4_gate_ick {
+	#clock-cells = <0>;
+	compatible = "ti,composite-interface-clock";
+	clocks = <&l4_ick>;
+	ti,bit-shift = <5>;
+	reg = <0x0a10>;
+};
+
+usb_l4_div_ick: usb_l4_div_ick {
+	#clock-cells = <0>;
+	compatible = "ti,composite-divider-clock";
+	clocks = <&l4_ick>;
+	ti,bit-shift = <4>;
+	ti,max-div = <1>;
+	reg = <0x0a40>;
+	ti,index-starts-at-one;
+};
+
+usb_l4_ick: usb_l4_ick {
+	#clock-cells = <0>;
+	compatible = "ti,composite-clock";
+	clocks = <&usb_l4_gate_ick>, <&usb_l4_div_ick>;
+};
diff --git a/drivers/clk/ti/Makefile b/drivers/clk/ti/Makefile
index 533efb4..a4a7595 100644
--- a/drivers/clk/ti/Makefile
+++ b/drivers/clk/ti/Makefile
@@ -1,3 +1,3 @@
 ifneq ($(CONFIG_OF),)
-obj-y					+= clk.o dpll.o autoidle.o
+obj-y					+= clk.o dpll.o autoidle.o composite.o
 endif
diff --git a/drivers/clk/ti/composite.c b/drivers/clk/ti/composite.c
new file mode 100644
index 0000000..9ce7e54
--- /dev/null
+++ b/drivers/clk/ti/composite.c
@@ -0,0 +1,222 @@
+/*
+ * TI composite clock support
+ *
+ * Copyright (C) 2013 Texas Instruments, Inc.
+ *
+ * Tero Kristo <t-kristo@xxxxxx>
+ *
+ * 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/io.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/clk/ti.h>
+#include <linux/list.h>
+
+#define to_clk_divider(_hw) container_of(_hw, struct clk_divider, hw)
+
+static unsigned long ti_composite_recalc_rate(struct clk_hw *hw,
+					      unsigned long parent_rate)
+{
+	return clk_divider_ops.recalc_rate(hw, parent_rate);
+}
+
+static long ti_composite_round_rate(struct clk_hw *hw, unsigned long rate,
+				    unsigned long *prate)
+{
+	return -EINVAL;
+}
+
+static int ti_composite_set_rate(struct clk_hw *hw, unsigned long rate,
+				 unsigned long parent_rate)
+{
+	return -EINVAL;
+}
+
+static const struct clk_ops ti_composite_divider_ops = {
+	.recalc_rate	= &ti_composite_recalc_rate,
+	.round_rate	= &ti_composite_round_rate,
+	.set_rate	= &ti_composite_set_rate,
+};
+
+static const struct clk_ops ti_composite_gate_ops = {
+	.enable		= &omap2_dflt_clk_enable,
+	.disable	= &omap2_dflt_clk_disable,
+	.is_enabled	= &omap2_dflt_clk_is_enabled,
+};
+
+struct component_clk {
+	int num_parents;
+	const char **parent_names;
+	struct device_node *node;
+	int type;
+	struct clk_hw *hw;
+	struct list_head link;
+};
+
+static const char * __initdata component_clk_types[] = {
+	"mux", "gate", "divider",
+};
+
+static LIST_HEAD(component_clks);
+
+static struct component_clk *_lookup_component(struct device_node *node, int i)
+{
+	int rc;
+	struct of_phandle_args clkspec;
+	struct component_clk *comp;
+
+	rc = of_parse_phandle_with_args(node, "clocks", "#clock-cells", i,
+					&clkspec);
+	if (rc)
+		return NULL;
+
+	list_for_each_entry(comp, &component_clks, link) {
+		if (comp->node == clkspec.np)
+			return comp;
+	}
+	return NULL;
+}
+
+static inline struct clk_hw *_get_hw(struct component_clk *clk)
+{
+	if (clk)
+		return clk->hw;
+
+	return NULL;
+}
+
+static int __init of_ti_composite_clk_setup(struct device_node *node,
+					    struct regmap *regmap)
+{
+	int num_clks;
+	int i;
+	struct clk *clk;
+	struct component_clk *comp;
+	struct component_clk *clks[3] = { NULL };
+	const char *name = node->name;
+	int num_parents = 0;
+	const char **parent_names = NULL;
+	int ret = 0;
+
+	/* Number of component clocks to be put inside this clock */
+	num_clks = of_clk_get_parent_count(node);
+
+	if (num_clks < 1) {
+		pr_err("%s: ti composite clk %s must have component(s)\n",
+		       __func__, name);
+		return -EINVAL;
+	}
+
+	/* Check for presence of each component clock */
+	for (i = 0; i < num_clks; i++) {
+		comp = _lookup_component(node, i);
+		if (!comp)
+			return -EAGAIN;
+		if (clks[comp->type] != NULL) {
+			pr_err("%s: duplicate component types for %s (%s)!\n",
+			       __func__, name, component_clk_types[comp->type]);
+			return -EINVAL;
+		}
+		clks[comp->type] = comp;
+	}
+
+	/* All components exists, proceed with registration */
+	for (i = 0; i < 3; i++) {
+		if (!clks[i])
+			continue;
+		if (clks[i]->num_parents) {
+			num_parents = clks[i]->num_parents;
+			parent_names = clks[i]->parent_names;
+		}
+	}
+
+	/* Enforce mux parents if exists */
+	comp = clks[CLK_COMPONENT_TYPE_MUX];
+	if (comp) {
+		num_parents = comp->num_parents;
+		parent_names = comp->parent_names;
+	}
+
+	if (!num_parents) {
+		pr_err("%s: no parents found for %s!\n", __func__,
+		       name);
+		return -EINVAL;
+	}
+
+	clk = clk_register_composite(NULL, name, parent_names, num_parents,
+				     _get_hw(clks[CLK_COMPONENT_TYPE_MUX]),
+				     &clk_mux_ops,
+				     _get_hw(clks[CLK_COMPONENT_TYPE_DIVIDER]),
+				     &ti_composite_divider_ops,
+				     _get_hw(clks[CLK_COMPONENT_TYPE_GATE]),
+				     &ti_composite_gate_ops, 0);
+
+	if (!IS_ERR(clk)) {
+		of_clk_add_provider(node, of_clk_src_simple_get, clk);
+		goto cleanup;
+	}
+
+	ret = PTR_ERR(clk);
+cleanup:
+	/* Free component clock list entries */
+	for (i = 0; i < 3; i++) {
+		if (!clks[i])
+			continue;
+		list_del(&clks[i]->link);
+		kfree(clks[i]);
+	}
+
+	return ret;
+}
+CLK_OF_DECLARE(ti_composite_clock, "ti,composite-clock",
+	       of_ti_composite_clk_setup);
+
+int __init ti_clk_add_component(struct device_node *node, struct clk_hw *hw,
+				int type)
+{
+	int num_parents;
+	const char **parent_names;
+	struct component_clk *clk;
+	int i;
+
+	num_parents = of_clk_get_parent_count(node);
+
+	if (num_parents < 1) {
+		pr_err("%s: component-clock %s must have parent(s)\n", __func__,
+		       node->name);
+		return -EINVAL;
+	}
+
+	parent_names = kzalloc((sizeof(char *) * num_parents), GFP_KERNEL);
+	if (!parent_names)
+		return -ENOMEM;
+
+	for (i = 0; i < num_parents; i++)
+		parent_names[i] = of_clk_get_parent_name(node, i);
+
+	clk = kzalloc(sizeof(*clk), GFP_KERNEL);
+	if (!clk) {
+		kfree(parent_names);
+		return -ENOMEM;
+	}
+
+	clk->num_parents = num_parents;
+	clk->parent_names = parent_names;
+	clk->hw = hw;
+	clk->node = node;
+	clk->type = type;
+	list_add(&clk->link, &component_clks);
+
+	return 0;
+}
diff --git a/include/linux/clk/ti.h b/include/linux/clk/ti.h
index e45005c..96c9725 100644
--- a/include/linux/clk/ti.h
+++ b/include/linux/clk/ti.h
@@ -137,6 +137,13 @@ struct clk_hw_omap {
 /* DPLL Type and DCO Selection Flags */
 #define DPLL_J_TYPE		0x1
 
+/* Composite clock component types */
+enum {
+	CLK_COMPONENT_TYPE_MUX = 0,
+	CLK_COMPONENT_TYPE_GATE,
+	CLK_COMPONENT_TYPE_DIVIDER
+};
+
 /**
  * struct ti_dt_clk - OMAP DT clock alias declarations
  * @lk: clock lookup definition
@@ -179,6 +186,7 @@ int omap3_dpll4_set_rate(struct clk_hw *clk, unsigned long rate,
 void ti_dt_clocks_register(struct ti_dt_clk *oclks);
 void ti_dt_clk_init_provider(struct device_node *np, struct regmap *regmap);
 int of_ti_autoidle_setup(struct device_node *node, struct regmap *regmap);
+int ti_clk_add_component(struct device_node *node, struct clk_hw *hw, int type);
 
 #ifdef CONFIG_OF
 void of_ti_clk_allow_autoidle_all(void);
-- 
1.7.9.5

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