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
27static 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
32	return parent_rate * fix->mult / fix->div;
33}
34
35static long clk_factor_round_rate(struct clk_hw *hw, unsigned long rate,
36				unsigned long *prate)
37{
38	struct clk_fixed_factor *fix = to_clk_fixed_factor(hw);
39
40	if (__clk_get_flags(hw->clk) & CLK_SET_RATE_PARENT) {
41		unsigned long best_parent;
42
43		best_parent = (rate / fix->mult) * fix->div;
44		*prate = __clk_round_rate(__clk_get_parent(hw->clk),
45				best_parent);
46	}
47
48	return (*prate / fix->div) * fix->mult;
49}
50
51static int clk_factor_set_rate(struct clk_hw *hw, unsigned long rate,
52				unsigned long parent_rate)
53{
54	return 0;
55}
56
57struct clk_ops clk_fixed_factor_ops = {
58	.round_rate = clk_factor_round_rate,
59	.set_rate = clk_factor_set_rate,
60	.recalc_rate = clk_factor_recalc_rate,
61};
62EXPORT_SYMBOL_GPL(clk_fixed_factor_ops);
63
64struct clk *clk_register_fixed_factor(struct device *dev, const char *name,
65		const char *parent_name, unsigned long flags,
66		unsigned int mult, unsigned int div)
67{
68	struct clk_fixed_factor *fix;
69	struct clk_init_data init;
70	struct clk *clk;
71
72	fix = kmalloc(sizeof(*fix), GFP_KERNEL);
73	if (!fix) {
74		pr_err("%s: could not allocate fixed factor clk\n", __func__);
75		return ERR_PTR(-ENOMEM);
76	}
77
78	/* struct clk_fixed_factor assignments */
79	fix->mult = mult;
80	fix->div = div;
81	fix->hw.init = &init;
82
83	init.name = name;
84	init.ops = &clk_fixed_factor_ops;
85	init.flags = flags;
86	init.parent_names = &parent_name;
87	init.num_parents = 1;
88
89	clk = clk_register(dev, &fix->hw);
90
91	if (IS_ERR(clk))
92		kfree(fix);
93
94	return clk;
95}