tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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
18/*
19 * DOC: basic fixed-rate clock that cannot gate
20 *
21 * Traits of this clock:
22 * prepare - clk_(un)prepare only ensures parents are prepared
23 * enable - clk_enable only ensures parents are enabled
24 * rate - rate is always a fixed value. No clk_set_rate support
25 * parent - fixed parent. No clk_set_parent support
26 */
27
28#define to_clk_fixed_rate(_hw) container_of(_hw, struct clk_fixed_rate, hw)
29
30static unsigned long clk_fixed_rate_recalc_rate(struct clk_hw *hw,
31 unsigned long parent_rate)
32{
33 return to_clk_fixed_rate(hw)->fixed_rate;
34}
35
36const struct clk_ops clk_fixed_rate_ops = {
37 .recalc_rate = clk_fixed_rate_recalc_rate,
38};
39EXPORT_SYMBOL_GPL(clk_fixed_rate_ops);
40
41/**
42 * clk_register_fixed_rate - register fixed-rate clock with the clock framework
43 * @dev: device that is registering this clock
44 * @name: name of this clock
45 * @parent_name: name of clock's parent
46 * @flags: framework-specific flags
47 * @fixed_rate: non-adjustable clock rate
48 */
49struct clk *clk_register_fixed_rate(struct device *dev, const char *name,
50 const char *parent_name, unsigned long flags,
51 unsigned long fixed_rate)
52{
53 struct clk_fixed_rate *fixed;
54 struct clk *clk;
55 struct clk_init_data init;
56
57 /* allocate fixed-rate clock */
58 fixed = kzalloc(sizeof(struct clk_fixed_rate), GFP_KERNEL);
59 if (!fixed) {
60 pr_err("%s: could not allocate fixed clk\n", __func__);
61 return ERR_PTR(-ENOMEM);
62 }
63
64 init.name = name;
65 init.ops = &clk_fixed_rate_ops;
66 init.flags = flags;
67 init.parent_names = (parent_name ? &parent_name: NULL);
68 init.num_parents = (parent_name ? 1 : 0);
69
70 /* struct clk_fixed_rate assignments */
71 fixed->fixed_rate = fixed_rate;
72 fixed->hw.init = &init;
73
74 /* register the clock */
75 clk = clk_register(dev, &fixed->hw);
76
77 if (IS_ERR(clk))
78 kfree(fixed);
79
80 return clk;
81}