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Mike Turquette9d9f78e2012-03-15 23:11:20 -07001/*
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>
Grant Likely015ba402012-04-07 21:39:39 -050017#include <linux/of.h>
Mike Turquette9d9f78e2012-03-15 23:11:20 -070018
19/*
20 * DOC: basic fixed-rate clock that cannot gate
21 *
22 * Traits of this clock:
23 * prepare - clk_(un)prepare only ensures parents are prepared
24 * enable - clk_enable only ensures parents are enabled
25 * rate - rate is always a fixed value. No clk_set_rate support
26 * parent - fixed parent. No clk_set_parent support
27 */
28
29#define to_clk_fixed_rate(_hw) container_of(_hw, struct clk_fixed_rate, hw)
30
31static unsigned long clk_fixed_rate_recalc_rate(struct clk_hw *hw,
32 unsigned long parent_rate)
33{
34 return to_clk_fixed_rate(hw)->fixed_rate;
35}
Mike Turquette9d9f78e2012-03-15 23:11:20 -070036
Shawn Guo822c2502012-03-27 15:23:22 +080037const struct clk_ops clk_fixed_rate_ops = {
Mike Turquette9d9f78e2012-03-15 23:11:20 -070038 .recalc_rate = clk_fixed_rate_recalc_rate,
39};
40EXPORT_SYMBOL_GPL(clk_fixed_rate_ops);
41
Mike Turquette27d54592012-03-26 17:51:03 -070042/**
43 * clk_register_fixed_rate - register fixed-rate clock with the clock framework
44 * @dev: device that is registering this clock
45 * @name: name of this clock
46 * @parent_name: name of clock's parent
47 * @flags: framework-specific flags
48 * @fixed_rate: non-adjustable clock rate
49 */
Mike Turquette9d9f78e2012-03-15 23:11:20 -070050struct clk *clk_register_fixed_rate(struct device *dev, const char *name,
51 const char *parent_name, unsigned long flags,
52 unsigned long fixed_rate)
53{
54 struct clk_fixed_rate *fixed;
Mike Turquette27d54592012-03-26 17:51:03 -070055 struct clk *clk;
Saravana Kannan0197b3e2012-04-25 22:58:56 -070056 struct clk_init_data init;
Mike Turquette9d9f78e2012-03-15 23:11:20 -070057
Mike Turquette27d54592012-03-26 17:51:03 -070058 /* allocate fixed-rate clock */
Mike Turquette9d9f78e2012-03-15 23:11:20 -070059 fixed = kzalloc(sizeof(struct clk_fixed_rate), GFP_KERNEL);
Mike Turquette9d9f78e2012-03-15 23:11:20 -070060 if (!fixed) {
61 pr_err("%s: could not allocate fixed clk\n", __func__);
62 return ERR_PTR(-ENOMEM);
63 }
64
Saravana Kannan0197b3e2012-04-25 22:58:56 -070065 init.name = name;
66 init.ops = &clk_fixed_rate_ops;
Rajendra Nayakf7d8caa2012-06-01 14:02:47 +053067 init.flags = flags | CLK_IS_BASIC;
Saravana Kannan0197b3e2012-04-25 22:58:56 -070068 init.parent_names = (parent_name ? &parent_name: NULL);
69 init.num_parents = (parent_name ? 1 : 0);
70
Mike Turquette9d9f78e2012-03-15 23:11:20 -070071 /* struct clk_fixed_rate assignments */
72 fixed->fixed_rate = fixed_rate;
Saravana Kannan0197b3e2012-04-25 22:58:56 -070073 fixed->hw.init = &init;
Mike Turquette9d9f78e2012-03-15 23:11:20 -070074
Mike Turquette27d54592012-03-26 17:51:03 -070075 /* register the clock */
Saravana Kannan0197b3e2012-04-25 22:58:56 -070076 clk = clk_register(dev, &fixed->hw);
Mike Turquette27d54592012-03-26 17:51:03 -070077
78 if (IS_ERR(clk))
79 kfree(fixed);
80
81 return clk;
Mike Turquette9d9f78e2012-03-15 23:11:20 -070082}
Stephen Boyd389ae052013-07-24 17:43:29 -070083EXPORT_SYMBOL_GPL(clk_register_fixed_rate);
Grant Likely015ba402012-04-07 21:39:39 -050084
85#ifdef CONFIG_OF
86/**
87 * of_fixed_clk_setup() - Setup function for simple fixed rate clock
88 */
Denis Efremove4eda8e2013-01-06 18:21:43 +040089void of_fixed_clk_setup(struct device_node *node)
Grant Likely015ba402012-04-07 21:39:39 -050090{
91 struct clk *clk;
92 const char *clk_name = node->name;
93 u32 rate;
94
95 if (of_property_read_u32(node, "clock-frequency", &rate))
96 return;
97
98 of_property_read_string(node, "clock-output-names", &clk_name);
99
100 clk = clk_register_fixed_rate(NULL, clk_name, NULL, CLK_IS_ROOT, rate);
Wei Yongjuncdfed3b2012-09-21 14:35:18 +0800101 if (!IS_ERR(clk))
Grant Likely015ba402012-04-07 21:39:39 -0500102 of_clk_add_provider(node, of_clk_src_simple_get, clk);
103}
104EXPORT_SYMBOL_GPL(of_fixed_clk_setup);
Prashant Gaikwadf2f6c252013-01-04 12:30:52 +0530105CLK_OF_DECLARE(fixed_clk, "fixed-clock", of_fixed_clk_setup);
Grant Likely015ba402012-04-07 21:39:39 -0500106#endif