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) 2014 Lucas Stach <l.stach@pengutronix.de>, Pengutronix
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 * http://www.opensource.org/licenses/gpl-license.html
9 * http://www.gnu.org/copyleft/gpl.html
10 */
11
12#include <linux/clk.h>
13#include <linux/clk-provider.h>
14#include <linux/slab.h>
15#include "clk.h"
16
17struct clk_cpu {
18 struct clk_hw hw;
19 struct clk *div;
20 struct clk *mux;
21 struct clk *pll;
22 struct clk *step;
23};
24
25static inline struct clk_cpu *to_clk_cpu(struct clk_hw *hw)
26{
27 return container_of(hw, struct clk_cpu, hw);
28}
29
30static unsigned long clk_cpu_recalc_rate(struct clk_hw *hw,
31 unsigned long parent_rate)
32{
33 struct clk_cpu *cpu = to_clk_cpu(hw);
34
35 return clk_get_rate(cpu->div);
36}
37
38static long clk_cpu_round_rate(struct clk_hw *hw, unsigned long rate,
39 unsigned long *prate)
40{
41 struct clk_cpu *cpu = to_clk_cpu(hw);
42
43 return clk_round_rate(cpu->pll, rate);
44}
45
46static int clk_cpu_set_rate(struct clk_hw *hw, unsigned long rate,
47 unsigned long parent_rate)
48{
49 struct clk_cpu *cpu = to_clk_cpu(hw);
50 int ret;
51
52 /* switch to PLL bypass clock */
53 ret = clk_set_parent(cpu->mux, cpu->step);
54 if (ret)
55 return ret;
56
57 /* reprogram PLL */
58 ret = clk_set_rate(cpu->pll, rate);
59 if (ret) {
60 clk_set_parent(cpu->mux, cpu->pll);
61 return ret;
62 }
63 /* switch back to PLL clock */
64 clk_set_parent(cpu->mux, cpu->pll);
65
66 /* Ensure the divider is what we expect */
67 clk_set_rate(cpu->div, rate);
68
69 return 0;
70}
71
72static const struct clk_ops clk_cpu_ops = {
73 .recalc_rate = clk_cpu_recalc_rate,
74 .round_rate = clk_cpu_round_rate,
75 .set_rate = clk_cpu_set_rate,
76};
77
78struct clk *imx_clk_cpu(const char *name, const char *parent_name,
79 struct clk *div, struct clk *mux, struct clk *pll,
80 struct clk *step)
81{
82 struct clk_cpu *cpu;
83 struct clk *clk;
84 struct clk_init_data init;
85
86 cpu = kzalloc(sizeof(*cpu), GFP_KERNEL);
87 if (!cpu)
88 return ERR_PTR(-ENOMEM);
89
90 cpu->div = div;
91 cpu->mux = mux;
92 cpu->pll = pll;
93 cpu->step = step;
94
95 init.name = name;
96 init.ops = &clk_cpu_ops;
97 init.flags = 0;
98 init.parent_names = &parent_name;
99 init.num_parents = 1;
100
101 cpu->hw.init = &init;
102
103 clk = clk_register(NULL, &cpu->hw);
104 if (IS_ERR(clk))
105 kfree(cpu);
106
107 return clk;
108}