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android-review.linaro.org / kernel / hikey-linaro / 9e58e1855c9815ad4944df90f695a7645c50f463 / . / arch / avr32 / mach-at32ap / cpufreq.c
blob: 235524b79193ec945e88dc8d20e0edf674b942d6 [file] [log] [blame]
Hans-Christian Egtvedt9e58e182007-06-04 16:10:57 +0200[diff] [blame^]1/*
2 * Copyright (C) 2004-2007 Atmel Corporation
3 *
4 * Based on MIPS implementation arch/mips/kernel/time.c
5 * Copyright 2001 MontaVista Software Inc.
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2 as
9 * published by the Free Software Foundation.
10 */
11
12/*#define DEBUG*/
13
14#include <linux/kernel.h>
15#include <linux/types.h>
16#include <linux/init.h>
17#include <linux/cpufreq.h>
18#include <linux/io.h>
19#include <linux/clk.h>
20#include <linux/err.h>
21#include <asm/system.h>
22
23static struct clk *cpuclk;
24
25static int at32_verify_speed(struct cpufreq_policy *policy)
26{
27 if (policy->cpu != 0)
28 return -EINVAL;
29
30 cpufreq_verify_within_limits(policy, policy->cpuinfo.min_freq,
31 policy->cpuinfo.max_freq);
32 return 0;
33}
34
35static unsigned int at32_get_speed(unsigned int cpu)
36{
37 /* No SMP support */
38 if (cpu)
39 return 0;
40 return (unsigned int)((clk_get_rate(cpuclk) + 500) / 1000);
41}
42
43static int at32_set_target(struct cpufreq_policy *policy,
44 unsigned int target_freq,
45 unsigned int relation)
46{
47 struct cpufreq_freqs freqs;
48 long freq;
49
50 /* Convert target_freq from kHz to Hz */
51 freq = clk_round_rate(cpuclk, target_freq * 1000);
52
53 /* Check if policy->min <= new_freq <= policy->max */
54 if(freq < (policy->min * 1000) || freq > (policy->max * 1000))
55 return -EINVAL;
56
57 pr_debug("cpufreq: requested frequency %u Hz\n", target_freq * 1000);
58
59 freqs.old = at32_get_speed(0);
60 freqs.new = (freq + 500) / 1000;
61 freqs.cpu = 0;
62 freqs.flags = 0;
63
64 cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
65 clk_set_rate(cpuclk, freq);
66 cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
67
68 pr_debug("cpufreq: set frequency %lu Hz\n", freq);
69
70 return 0;
71}
72
73static int __init at32_cpufreq_driver_init(struct cpufreq_policy *policy)
74{
75 if (policy->cpu != 0)
76 return -EINVAL;
77
78 cpuclk = clk_get(NULL, "cpu");
79 if (IS_ERR(cpuclk)) {
80 pr_debug("cpufreq: could not get CPU clk\n");
81 return PTR_ERR(cpuclk);
82 }
83
84 policy->cpuinfo.min_freq = (clk_round_rate(cpuclk, 1) + 500) / 1000;
85 policy->cpuinfo.max_freq = (clk_round_rate(cpuclk, ~0UL) + 500) / 1000;
86 policy->cpuinfo.transition_latency = 0;
87 policy->cur = at32_get_speed(0);
88 policy->min = policy->cpuinfo.min_freq;
89 policy->max = policy->cpuinfo.max_freq;
90 policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
91
92 printk("cpufreq: AT32AP CPU frequency driver\n");
93
94 return 0;
95}
96
97static struct cpufreq_driver at32_driver = {
98 .name = "at32ap",
99 .owner = THIS_MODULE,
100 .init = at32_cpufreq_driver_init,
101 .verify = at32_verify_speed,
102 .target = at32_set_target,
103 .get = at32_get_speed,
104 .flags = CPUFREQ_STICKY,
105};
106
107static int __init at32_cpufreq_init(void)
108{
109 return cpufreq_register_driver(&at32_driver);
110}
111
112arch_initcall(at32_cpufreq_init);