1/*
2 * Copyright (C) 2010-2011 Canonical Ltd <jeremy.kerr@canonical.com>
3 * Copyright (C) 2011-2012 Mike Turquette, Linaro Ltd <mturquette@linaro.org>
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License version 2 as
7 * published by the Free Software Foundation.
8 *
9 * Fixed rate clock implementation
10 */
11
12#include <linux/clk-provider.h>
13#include <linux/module.h>
14#include <linux/slab.h>
15#include <linux/io.h>
16#include <linux/err.h>
17#include <linux/of.h>
18
19/*
20 * DOC: basic fixed-rate clock that cannot gate
21 *
22 * Traits of this clock:
23 * prepare - clk_(un)prepare only ensures parents are prepared
24 * enable - clk_enable only ensures parents are enabled
25 * rate - rate is always a fixed value.  No clk_set_rate support
26 * parent - fixed parent.  No clk_set_parent support
27 */
28
29#define to_clk_fixed_rate(_hw) container_of(_hw, struct clk_fixed_rate, hw)
30
31static unsigned long clk_fixed_rate_recalc_rate(struct clk_hw *hw,
32		unsigned long parent_rate)
33{
34	return to_clk_fixed_rate(hw)->fixed_rate;
35}
36
37static unsigned long clk_fixed_rate_recalc_accuracy(struct clk_hw *hw,
38		unsigned long parent_accuracy)
39{
40	return to_clk_fixed_rate(hw)->fixed_accuracy;
41}
42
43const struct clk_ops clk_fixed_rate_ops = {
44	.recalc_rate = clk_fixed_rate_recalc_rate,
45	.recalc_accuracy = clk_fixed_rate_recalc_accuracy,
46};
47EXPORT_SYMBOL_GPL(clk_fixed_rate_ops);
48
49/**
50 * clk_register_fixed_rate_with_accuracy - register fixed-rate clock with the
51 *					   clock framework
52 * @dev: device that is registering this clock
53 * @name: name of this clock
54 * @parent_name: name of clock's parent
55 * @flags: framework-specific flags
56 * @fixed_rate: non-adjustable clock rate
57 * @fixed_accuracy: non-adjustable clock rate
58 */
59struct clk *clk_register_fixed_rate_with_accuracy(struct device *dev,
60		const char *name, const char *parent_name, unsigned long flags,
61		unsigned long fixed_rate, unsigned long fixed_accuracy)
62{
63	struct clk_fixed_rate *fixed;
64	struct clk *clk;
65	struct clk_init_data init;
66
67	/* allocate fixed-rate clock */
68	fixed = kzalloc(sizeof(struct clk_fixed_rate), GFP_KERNEL);
69	if (!fixed) {
70		pr_err("%s: could not allocate fixed clk\n", __func__);
71		return ERR_PTR(-ENOMEM);
72	}
73
74	init.name = name;
75	init.ops = &clk_fixed_rate_ops;
76	init.flags = flags | CLK_IS_BASIC;
77	init.parent_names = (parent_name ? &parent_name: NULL);
78	init.num_parents = (parent_name ? 1 : 0);
79
80	/* struct clk_fixed_rate assignments */
81	fixed->fixed_rate = fixed_rate;
82	fixed->fixed_accuracy = fixed_accuracy;
83	fixed->hw.init = &init;
84
85	/* register the clock */
86	clk = clk_register(dev, &fixed->hw);
87	if (IS_ERR(clk))
88		kfree(fixed);
89
90	return clk;
91}
92EXPORT_SYMBOL_GPL(clk_register_fixed_rate_with_accuracy);
93
94/**
95 * clk_register_fixed_rate - register fixed-rate clock with the clock framework
96 * @dev: device that is registering this clock
97 * @name: name of this clock
98 * @parent_name: name of clock's parent
99 * @flags: framework-specific flags
100 * @fixed_rate: non-adjustable clock rate
101 */
102struct clk *clk_register_fixed_rate(struct device *dev, const char *name,
103		const char *parent_name, unsigned long flags,
104		unsigned long fixed_rate)
105{
106	return clk_register_fixed_rate_with_accuracy(dev, name, parent_name,
107						     flags, fixed_rate, 0);
108}
109EXPORT_SYMBOL_GPL(clk_register_fixed_rate);
110
111#ifdef CONFIG_OF
112/**
113 * of_fixed_clk_setup() - Setup function for simple fixed rate clock
114 */
115void of_fixed_clk_setup(struct device_node *node)
116{
117	struct clk *clk;
118	const char *clk_name = node->name;
119	u32 rate;
120	u32 accuracy = 0;
121
122	if (of_property_read_u32(node, "clock-frequency", &rate))
123		return;
124
125	of_property_read_u32(node, "clock-accuracy", &accuracy);
126
127	of_property_read_string(node, "clock-output-names", &clk_name);
128
129	clk = clk_register_fixed_rate_with_accuracy(NULL, clk_name, NULL,
130						    CLK_IS_ROOT, rate,
131						    accuracy);
132	if (!IS_ERR(clk))
133		of_clk_add_provider(node, of_clk_src_simple_get, clk);
134}
135EXPORT_SYMBOL_GPL(of_fixed_clk_setup);
136CLK_OF_DECLARE(fixed_clk, "fixed-clock", of_fixed_clk_setup);
137#endif
138