1 /*
2  * Copyright (C) 2011 Sascha Hauer, Pengutronix <s.hauer@pengutronix.de>
3  *
4  * This program is free software; you can redistribute it and/or modify
5  * it under the terms of the GNU General Public License version 2 as
6  * published by the Free Software Foundation.
7  *
8  * Standard functionality for the common clock API.
9  */
10 #include <linux/module.h>
11 #include <linux/clk-provider.h>
12 #include <linux/slab.h>
13 #include <linux/err.h>
14 #include <linux/of.h>
15 
16 /*
17  * DOC: basic fixed multiplier and divider clock that cannot gate
18  *
19  * Traits of this clock:
20  * prepare - clk_prepare only ensures that parents are prepared
21  * enable - clk_enable only ensures that parents are enabled
22  * rate - rate is fixed.  clk->rate = parent->rate / div * mult
23  * parent - fixed parent.  No clk_set_parent support
24  */
25 
26 static unsigned long clk_factor_recalc_rate(struct clk_hw *hw,
27 		unsigned long parent_rate)
28 {
29 	struct clk_fixed_factor *fix = to_clk_fixed_factor(hw);
30 	unsigned long long int rate;
31 
32 	rate = (unsigned long long int)parent_rate * fix->mult;
33 	do_div(rate, fix->div);
34 	return (unsigned long)rate;
35 }
36 
37 static long clk_factor_round_rate(struct clk_hw *hw, unsigned long rate,
38 				unsigned long *prate)
39 {
40 	struct clk_fixed_factor *fix = to_clk_fixed_factor(hw);
41 
42 	if (clk_hw_get_flags(hw) & CLK_SET_RATE_PARENT) {
43 		unsigned long best_parent;
44 
45 		best_parent = (rate / fix->mult) * fix->div;
46 		*prate = clk_hw_round_rate(clk_hw_get_parent(hw), best_parent);
47 	}
48 
49 	return (*prate / fix->div) * fix->mult;
50 }
51 
52 static int clk_factor_set_rate(struct clk_hw *hw, unsigned long rate,
53 				unsigned long parent_rate)
54 {
55 	/*
56 	 * We must report success but we can do so unconditionally because
57 	 * clk_factor_round_rate returns values that ensure this call is a
58 	 * nop.
59 	 */
60 
61 	return 0;
62 }
63 
64 const struct clk_ops clk_fixed_factor_ops = {
65 	.round_rate = clk_factor_round_rate,
66 	.set_rate = clk_factor_set_rate,
67 	.recalc_rate = clk_factor_recalc_rate,
68 };
69 EXPORT_SYMBOL_GPL(clk_fixed_factor_ops);
70 
71 struct clk *clk_register_fixed_factor(struct device *dev, const char *name,
72 		const char *parent_name, unsigned long flags,
73 		unsigned int mult, unsigned int div)
74 {
75 	struct clk_fixed_factor *fix;
76 	struct clk_init_data init;
77 	struct clk *clk;
78 
79 	fix = kmalloc(sizeof(*fix), GFP_KERNEL);
80 	if (!fix)
81 		return ERR_PTR(-ENOMEM);
82 
83 	/* struct clk_fixed_factor assignments */
84 	fix->mult = mult;
85 	fix->div = div;
86 	fix->hw.init = &init;
87 
88 	init.name = name;
89 	init.ops = &clk_fixed_factor_ops;
90 	init.flags = flags | CLK_IS_BASIC;
91 	init.parent_names = &parent_name;
92 	init.num_parents = 1;
93 
94 	clk = clk_register(dev, &fix->hw);
95 
96 	if (IS_ERR(clk))
97 		kfree(fix);
98 
99 	return clk;
100 }
101 EXPORT_SYMBOL_GPL(clk_register_fixed_factor);
102 
103 void clk_unregister_fixed_factor(struct clk *clk)
104 {
105 	struct clk_hw *hw;
106 
107 	hw = __clk_get_hw(clk);
108 	if (!hw)
109 		return;
110 
111 	clk_unregister(clk);
112 	kfree(to_clk_fixed_factor(hw));
113 }
114 EXPORT_SYMBOL_GPL(clk_unregister_fixed_factor);
115 
116 #ifdef CONFIG_OF
117 /**
118  * of_fixed_factor_clk_setup() - Setup function for simple fixed factor clock
119  */
120 void __init of_fixed_factor_clk_setup(struct device_node *node)
121 {
122 	struct clk *clk;
123 	const char *clk_name = node->name;
124 	const char *parent_name;
125 	u32 div, mult;
126 
127 	if (of_property_read_u32(node, "clock-div", &div)) {
128 		pr_err("%s Fixed factor clock <%s> must have a clock-div property\n",
129 			__func__, node->name);
130 		return;
131 	}
132 
133 	if (of_property_read_u32(node, "clock-mult", &mult)) {
134 		pr_err("%s Fixed factor clock <%s> must have a clock-mult property\n",
135 			__func__, node->name);
136 		return;
137 	}
138 
139 	of_property_read_string(node, "clock-output-names", &clk_name);
140 	parent_name = of_clk_get_parent_name(node, 0);
141 
142 	clk = clk_register_fixed_factor(NULL, clk_name, parent_name, 0,
143 					mult, div);
144 	if (!IS_ERR(clk))
145 		of_clk_add_provider(node, of_clk_src_simple_get, clk);
146 }
147 EXPORT_SYMBOL_GPL(of_fixed_factor_clk_setup);
148 CLK_OF_DECLARE(fixed_factor_clk, "fixed-factor-clock",
149 		of_fixed_factor_clk_setup);
150 #endif
151