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review.evervolv.com / android_kernel_htc_msm8960 / 5af52b51f76d8f8dce0e5b2a33c20b2231c8046d / . / arch / avr32 / mach-at32ap / cpufreq.c
blob: 024c586e936c268956dbb59221e4ec8e2b77b129 [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
Haavard Skinnemoene3f91ca2008-10-23 11:23:08 +0200[diff] [blame]43static unsigned int ref_freq;
44static unsigned long loops_per_jiffy_ref;
45
Hans-Christian Egtvedt9e58e182007-06-04 16:10:57 +0200[diff] [blame]46static int at32_set_target(struct cpufreq_policy *policy,
47 unsigned int target_freq,
48 unsigned int relation)
49{
50 struct cpufreq_freqs freqs;
51 long freq;
52
53 /* Convert target_freq from kHz to Hz */
54 freq = clk_round_rate(cpuclk, target_freq * 1000);
55
56 /* Check if policy->min <= new_freq <= policy->max */
57 if(freq < (policy->min * 1000) || freq > (policy->max * 1000))
58 return -EINVAL;
59
60 pr_debug("cpufreq: requested frequency %u Hz\n", target_freq * 1000);
61
62 freqs.old = at32_get_speed(0);
63 freqs.new = (freq + 500) / 1000;
64 freqs.cpu = 0;
65 freqs.flags = 0;
66
Haavard Skinnemoene3f91ca2008-10-23 11:23:08 +0200[diff] [blame]67 if (!ref_freq) {
68 ref_freq = freqs.old;
69 loops_per_jiffy_ref = boot_cpu_data.loops_per_jiffy;
70 }
71
Hans-Christian Egtvedt9e58e182007-06-04 16:10:57 +0200[diff] [blame]72 cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
Haavard Skinnemoene3f91ca2008-10-23 11:23:08 +0200[diff] [blame]73 if (freqs.old < freqs.new)
74 boot_cpu_data.loops_per_jiffy = cpufreq_scale(
75 loops_per_jiffy_ref, ref_freq, freqs.new);
Hans-Christian Egtvedt9e58e182007-06-04 16:10:57 +0200[diff] [blame]76 clk_set_rate(cpuclk, freq);
Haavard Skinnemoene3f91ca2008-10-23 11:23:08 +0200[diff] [blame]77 if (freqs.new < freqs.old)
78 boot_cpu_data.loops_per_jiffy = cpufreq_scale(
79 loops_per_jiffy_ref, ref_freq, freqs.new);
Hans-Christian Egtvedt9e58e182007-06-04 16:10:57 +0200[diff] [blame]80 cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
81
82 pr_debug("cpufreq: set frequency %lu Hz\n", freq);
83
84 return 0;
85}
86
87static int __init at32_cpufreq_driver_init(struct cpufreq_policy *policy)
88{
89 if (policy->cpu != 0)
90 return -EINVAL;
91
92 cpuclk = clk_get(NULL, "cpu");
93 if (IS_ERR(cpuclk)) {
94 pr_debug("cpufreq: could not get CPU clk\n");
95 return PTR_ERR(cpuclk);
96 }
97
98 policy->cpuinfo.min_freq = (clk_round_rate(cpuclk, 1) + 500) / 1000;
99 policy->cpuinfo.max_freq = (clk_round_rate(cpuclk, ~0UL) + 500) / 1000;
100 policy->cpuinfo.transition_latency = 0;
101 policy->cur = at32_get_speed(0);
102 policy->min = policy->cpuinfo.min_freq;
103 policy->max = policy->cpuinfo.max_freq;
Hans-Christian Egtvedt9e58e182007-06-04 16:10:57 +0200[diff] [blame]104
105 printk("cpufreq: AT32AP CPU frequency driver\n");
106
107 return 0;
108}
109
110static struct cpufreq_driver at32_driver = {
111 .name = "at32ap",
112 .owner = THIS_MODULE,
113 .init = at32_cpufreq_driver_init,
114 .verify = at32_verify_speed,
115 .target = at32_set_target,
116 .get = at32_get_speed,
117 .flags = CPUFREQ_STICKY,
118};
119
120static int __init at32_cpufreq_init(void)
121{
122 return cpufreq_register_driver(&at32_driver);
123}
Haavard Skinnemoenf04d2642008-05-27 09:37:42 +0200[diff] [blame]124late_initcall(at32_cpufreq_init);