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 
15 /*
16  * DOC: basic fixed multiplier and divider clock that cannot gate
17  *
18  * Traits of this clock:
19  * prepare - clk_prepare only ensures that parents are prepared
20  * enable - clk_enable only ensures that parents are enabled
21  * rate - rate is fixed.  clk->rate = parent->rate / div * mult
22  * parent - fixed parent.  No clk_set_parent support
23  */
24 
25 #define to_clk_fixed_factor(_hw) container_of(_hw, struct clk_fixed_factor, hw)
26 
27 static unsigned long clk_factor_recalc_rate(struct clk_hw *hw,
28 		unsigned long parent_rate)
29 {
30 	struct clk_fixed_factor *fix = to_clk_fixed_factor(hw);
31 	unsigned long long int rate;
32 
33 	rate = (unsigned long long int)parent_rate * fix->mult;
34 	do_div(rate, fix->div);
35 	return (unsigned long)rate;
36 }
37 
38 static long clk_factor_round_rate(struct clk_hw *hw, unsigned long rate,
39 				unsigned long *prate)
40 {
41 	struct clk_fixed_factor *fix = to_clk_fixed_factor(hw);
42 
43 	if (__clk_get_flags(hw->clk) & CLK_SET_RATE_PARENT) {
44 		unsigned long best_parent;
45 
46 		best_parent = (rate / fix->mult) * fix->div;
47 		*prate = __clk_round_rate(__clk_get_parent(hw->clk),
48 				best_parent);
49 	}
50 
51 	return (*prate / fix->div) * fix->mult;
52 }
53 
54 static int clk_factor_set_rate(struct clk_hw *hw, unsigned long rate,
55 				unsigned long parent_rate)
56 {
57 	return 0;
58 }
59 
60 struct clk_ops clk_fixed_factor_ops = {
61 	.round_rate = clk_factor_round_rate,
62 	.set_rate = clk_factor_set_rate,
63 	.recalc_rate = clk_factor_recalc_rate,
64 };
65 EXPORT_SYMBOL_GPL(clk_fixed_factor_ops);
66 
67 struct clk *clk_register_fixed_factor(struct device *dev, const char *name,
68 		const char *parent_name, unsigned long flags,
69 		unsigned int mult, unsigned int div)
70 {
71 	struct clk_fixed_factor *fix;
72 	struct clk_init_data init;
73 	struct clk *clk;
74 
75 	fix = kmalloc(sizeof(*fix), GFP_KERNEL);
76 	if (!fix) {
77 		pr_err("%s: could not allocate fixed factor clk\n", __func__);
78 		return ERR_PTR(-ENOMEM);
79 	}
80 
81 	/* struct clk_fixed_factor assignments */
82 	fix->mult = mult;
83 	fix->div = div;
84 	fix->hw.init = &init;
85 
86 	init.name = name;
87 	init.ops = &clk_fixed_factor_ops;
88 	init.flags = flags | CLK_IS_BASIC;
89 	init.parent_names = &parent_name;
90 	init.num_parents = 1;
91 
92 	clk = clk_register(dev, &fix->hw);
93 
94 	if (IS_ERR(clk))
95 		kfree(fix);
96 
97 	return clk;
98 }
99