blob: 654488723cb5d00746b5e08ebb5f88e9beac8cd0 [file] [log] [blame]
Hans-Christian Egtvedt9e58e182007-06-04 16:10:57 +02001/*
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>
Paul Gortmaker09cf6a22011-08-01 12:55:26 -040021#include <linux/export.h>
Hans-Christian Egtvedt9e58e182007-06-04 16:10:57 +020022
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 +020043static unsigned int ref_freq;
44static unsigned long loops_per_jiffy_ref;
45
Hans-Christian Egtvedt9e58e182007-06-04 16:10:57 +020046static 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;
Hans-Christian Egtvedt9e58e182007-06-04 16:10:57 +020064 freqs.flags = 0;
65
Haavard Skinnemoene3f91ca2008-10-23 11:23:08 +020066 if (!ref_freq) {
67 ref_freq = freqs.old;
68 loops_per_jiffy_ref = boot_cpu_data.loops_per_jiffy;
69 }
70
Viresh Kumarb43a7ff2013-03-24 11:56:43 +053071 cpufreq_notify_transition(policy, &freqs, CPUFREQ_PRECHANGE);
Haavard Skinnemoene3f91ca2008-10-23 11:23:08 +020072 if (freqs.old < freqs.new)
73 boot_cpu_data.loops_per_jiffy = cpufreq_scale(
74 loops_per_jiffy_ref, ref_freq, freqs.new);
Hans-Christian Egtvedt9e58e182007-06-04 16:10:57 +020075 clk_set_rate(cpuclk, freq);
Haavard Skinnemoene3f91ca2008-10-23 11:23:08 +020076 if (freqs.new < freqs.old)
77 boot_cpu_data.loops_per_jiffy = cpufreq_scale(
78 loops_per_jiffy_ref, ref_freq, freqs.new);
Viresh Kumarb43a7ff2013-03-24 11:56:43 +053079 cpufreq_notify_transition(policy, &freqs, CPUFREQ_POSTCHANGE);
Hans-Christian Egtvedt9e58e182007-06-04 16:10:57 +020080
81 pr_debug("cpufreq: set frequency %lu Hz\n", freq);
82
83 return 0;
84}
85
86static int __init at32_cpufreq_driver_init(struct cpufreq_policy *policy)
87{
88 if (policy->cpu != 0)
89 return -EINVAL;
90
91 cpuclk = clk_get(NULL, "cpu");
92 if (IS_ERR(cpuclk)) {
93 pr_debug("cpufreq: could not get CPU clk\n");
94 return PTR_ERR(cpuclk);
95 }
96
97 policy->cpuinfo.min_freq = (clk_round_rate(cpuclk, 1) + 500) / 1000;
98 policy->cpuinfo.max_freq = (clk_round_rate(cpuclk, ~0UL) + 500) / 1000;
99 policy->cpuinfo.transition_latency = 0;
100 policy->cur = at32_get_speed(0);
101 policy->min = policy->cpuinfo.min_freq;
102 policy->max = policy->cpuinfo.max_freq;
Hans-Christian Egtvedt9e58e182007-06-04 16:10:57 +0200103
104 printk("cpufreq: AT32AP CPU frequency driver\n");
105
106 return 0;
107}
108
109static struct cpufreq_driver at32_driver = {
110 .name = "at32ap",
111 .owner = THIS_MODULE,
112 .init = at32_cpufreq_driver_init,
113 .verify = at32_verify_speed,
114 .target = at32_set_target,
115 .get = at32_get_speed,
116 .flags = CPUFREQ_STICKY,
117};
118
119static int __init at32_cpufreq_init(void)
120{
121 return cpufreq_register_driver(&at32_driver);
122}
Haavard Skinnemoenf04d2642008-05-27 09:37:42 +0200123late_initcall(at32_cpufreq_init);