| Hans-Christian Egtvedt | 9e58e18 | 2007-06-04 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 | |
| 23 | static struct clk *cpuclk; |
| 24 | |
| 25 | static 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 | |
| 35 | static 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 | |
| 43 | static 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 | |
| 73 | static 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 | |
| 97 | static 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 | |
| 107 | static int __init at32_cpufreq_init(void) |
| 108 | { |
| 109 | return cpufreq_register_driver(&at32_driver); |
| 110 | } |
| 111 | |
| 112 | arch_initcall(at32_cpufreq_init); |