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 #define to_clk_fixed_factor(_hw) container_of(_hw, struct clk_fixed_factor, hw)
27
clk_factor_recalc_rate(struct clk_hw * hw,unsigned long parent_rate)28 static unsigned long clk_factor_recalc_rate(struct clk_hw *hw,
29 unsigned long parent_rate)
30 {
31 struct clk_fixed_factor *fix = to_clk_fixed_factor(hw);
32 unsigned long long int rate;
33
34 rate = (unsigned long long int)parent_rate * fix->mult;
35 do_div(rate, fix->div);
36 return (unsigned long)rate;
37 }
38
clk_factor_round_rate(struct clk_hw * hw,unsigned long rate,unsigned long * prate)39 static long clk_factor_round_rate(struct clk_hw *hw, unsigned long rate,
40 unsigned long *prate)
41 {
42 struct clk_fixed_factor *fix = to_clk_fixed_factor(hw);
43
44 if (__clk_get_flags(hw->clk) & CLK_SET_RATE_PARENT) {
45 unsigned long best_parent;
46
47 best_parent = (rate / fix->mult) * fix->div;
48 *prate = __clk_round_rate(__clk_get_parent(hw->clk),
49 best_parent);
50 }
51
52 return (*prate / fix->div) * fix->mult;
53 }
54
clk_factor_set_rate(struct clk_hw * hw,unsigned long rate,unsigned long parent_rate)55 static int clk_factor_set_rate(struct clk_hw *hw, unsigned long rate,
56 unsigned long parent_rate)
57 {
58 return 0;
59 }
60
61 struct clk_ops clk_fixed_factor_ops = {
62 .round_rate = clk_factor_round_rate,
63 .set_rate = clk_factor_set_rate,
64 .recalc_rate = clk_factor_recalc_rate,
65 };
66 EXPORT_SYMBOL_GPL(clk_fixed_factor_ops);
67
clk_register_fixed_factor(struct device * dev,const char * name,const char * parent_name,unsigned long flags,unsigned int mult,unsigned int div)68 struct clk *clk_register_fixed_factor(struct device *dev, const char *name,
69 const char *parent_name, unsigned long flags,
70 unsigned int mult, unsigned int div)
71 {
72 struct clk_fixed_factor *fix;
73 struct clk_init_data init;
74 struct clk *clk;
75
76 fix = kmalloc(sizeof(*fix), GFP_KERNEL);
77 if (!fix) {
78 pr_err("%s: could not allocate fixed factor clk\n", __func__);
79 return ERR_PTR(-ENOMEM);
80 }
81
82 /* struct clk_fixed_factor assignments */
83 fix->mult = mult;
84 fix->div = div;
85 fix->hw.init = &init;
86
87 init.name = name;
88 init.ops = &clk_fixed_factor_ops;
89 init.flags = flags | CLK_IS_BASIC;
90 init.parent_names = &parent_name;
91 init.num_parents = 1;
92
93 clk = clk_register(dev, &fix->hw);
94
95 if (IS_ERR(clk))
96 kfree(fix);
97
98 return clk;
99 }
100 EXPORT_SYMBOL_GPL(clk_register_fixed_factor);
101
102 #ifdef CONFIG_OF
103 /**
104 * of_fixed_factor_clk_setup() - Setup function for simple fixed factor clock
105 */
of_fixed_factor_clk_setup(struct device_node * node)106 void __init of_fixed_factor_clk_setup(struct device_node *node)
107 {
108 struct clk *clk;
109 const char *clk_name = node->name;
110 const char *parent_name;
111 u32 div, mult;
112
113 if (of_property_read_u32(node, "clock-div", &div)) {
114 pr_err("%s Fixed factor clock <%s> must have a clock-div property\n",
115 __func__, node->name);
116 return;
117 }
118
119 if (of_property_read_u32(node, "clock-mult", &mult)) {
120 pr_err("%s Fixed factor clock <%s> must have a clock-mult property\n",
121 __func__, node->name);
122 return;
123 }
124
125 of_property_read_string(node, "clock-output-names", &clk_name);
126 parent_name = of_clk_get_parent_name(node, 0);
127
128 clk = clk_register_fixed_factor(NULL, clk_name, parent_name, 0,
129 mult, div);
130 if (!IS_ERR(clk))
131 of_clk_add_provider(node, of_clk_src_simple_get, clk);
132 }
133 EXPORT_SYMBOL_GPL(of_fixed_factor_clk_setup);
134 CLK_OF_DECLARE(fixed_factor_clk, "fixed-factor-clock",
135 of_fixed_factor_clk_setup);
136 #endif
137