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Diffstat (limited to 'arch/avr32/mach-at32ap/cpufreq.c')
-rw-r--r--arch/avr32/mach-at32ap/cpufreq.c112
1 files changed, 112 insertions, 0 deletions
diff --git a/arch/avr32/mach-at32ap/cpufreq.c b/arch/avr32/mach-at32ap/cpufreq.c
new file mode 100644
index 000000000000..235524b79193
--- /dev/null
+++ b/arch/avr32/mach-at32ap/cpufreq.c
@@ -0,0 +1,112 @@
+/*
+ * Copyright (C) 2004-2007 Atmel Corporation
+ *
+ * Based on MIPS implementation arch/mips/kernel/time.c
+ * Copyright 2001 MontaVista Software Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+/*#define DEBUG*/
+
+#include <linux/kernel.h>
+#include <linux/types.h>
+#include <linux/init.h>
+#include <linux/cpufreq.h>
+#include <linux/io.h>
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <asm/system.h>
+
+static struct clk *cpuclk;
+
+static int at32_verify_speed(struct cpufreq_policy *policy)
+{
+ if (policy->cpu != 0)
+ return -EINVAL;
+
+ cpufreq_verify_within_limits(policy, policy->cpuinfo.min_freq,
+ policy->cpuinfo.max_freq);
+ return 0;
+}
+
+static unsigned int at32_get_speed(unsigned int cpu)
+{
+ /* No SMP support */
+ if (cpu)
+ return 0;
+ return (unsigned int)((clk_get_rate(cpuclk) + 500) / 1000);
+}
+
+static int at32_set_target(struct cpufreq_policy *policy,
+ unsigned int target_freq,
+ unsigned int relation)
+{
+ struct cpufreq_freqs freqs;
+ long freq;
+
+ /* Convert target_freq from kHz to Hz */
+ freq = clk_round_rate(cpuclk, target_freq * 1000);
+
+ /* Check if policy->min <= new_freq <= policy->max */
+ if(freq < (policy->min * 1000) || freq > (policy->max * 1000))
+ return -EINVAL;
+
+ pr_debug("cpufreq: requested frequency %u Hz\n", target_freq * 1000);
+
+ freqs.old = at32_get_speed(0);
+ freqs.new = (freq + 500) / 1000;
+ freqs.cpu = 0;
+ freqs.flags = 0;
+
+ cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
+ clk_set_rate(cpuclk, freq);
+ cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
+
+ pr_debug("cpufreq: set frequency %lu Hz\n", freq);
+
+ return 0;
+}
+
+static int __init at32_cpufreq_driver_init(struct cpufreq_policy *policy)
+{
+ if (policy->cpu != 0)
+ return -EINVAL;
+
+ cpuclk = clk_get(NULL, "cpu");
+ if (IS_ERR(cpuclk)) {
+ pr_debug("cpufreq: could not get CPU clk\n");
+ return PTR_ERR(cpuclk);
+ }
+
+ policy->cpuinfo.min_freq = (clk_round_rate(cpuclk, 1) + 500) / 1000;
+ policy->cpuinfo.max_freq = (clk_round_rate(cpuclk, ~0UL) + 500) / 1000;
+ policy->cpuinfo.transition_latency = 0;
+ policy->cur = at32_get_speed(0);
+ policy->min = policy->cpuinfo.min_freq;
+ policy->max = policy->cpuinfo.max_freq;
+ policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
+
+ printk("cpufreq: AT32AP CPU frequency driver\n");
+
+ return 0;
+}
+
+static struct cpufreq_driver at32_driver = {
+ .name = "at32ap",
+ .owner = THIS_MODULE,
+ .init = at32_cpufreq_driver_init,
+ .verify = at32_verify_speed,
+ .target = at32_set_target,
+ .get = at32_get_speed,
+ .flags = CPUFREQ_STICKY,
+};
+
+static int __init at32_cpufreq_init(void)
+{
+ return cpufreq_register_driver(&at32_driver);
+}
+
+arch_initcall(at32_cpufreq_init);