1 files changed, 127 insertions, 0 deletions
diff --git a/drivers/cpufreq/at32ap-cpufreq.c b/drivers/cpufreq/at32ap-cpufreq.c
new file mode 100644
index 000000000..7b612c8bb
--- /dev/null
+++ b/drivers/cpufreq/at32ap-cpufreq.c
@@ -0,0 +1,127 @@
+/*
+ * 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 <linux/export.h>
+#include <linux/slab.h>
+
+static struct cpufreq_frequency_table *freq_table;
+
+static unsigned int	ref_freq;
+static unsigned long	loops_per_jiffy_ref;
+
+static int at32_set_target(struct cpufreq_policy *policy, unsigned int index)
+{
+	unsigned int old_freq, new_freq;
+
+	old_freq = policy->cur;
+	new_freq = freq_table[index].frequency;
+
+	if (!ref_freq) {
+		ref_freq = old_freq;
+		loops_per_jiffy_ref = boot_cpu_data.loops_per_jiffy;
+	}
+
+	if (old_freq < new_freq)
+		boot_cpu_data.loops_per_jiffy = cpufreq_scale(
+				loops_per_jiffy_ref, ref_freq, new_freq);
+	clk_set_rate(policy->clk, new_freq * 1000);
+	if (new_freq < old_freq)
+		boot_cpu_data.loops_per_jiffy = cpufreq_scale(
+				loops_per_jiffy_ref, ref_freq, new_freq);
+
+	return 0;
+}
+
+static int at32_cpufreq_driver_init(struct cpufreq_policy *policy)
+{
+	unsigned int frequency, rate, min_freq;
+	struct clk *cpuclk;
+	int retval, steps, i;
+
+	if (policy->cpu != 0)
+		return -EINVAL;
+
+	cpuclk = clk_get(NULL, "cpu");
+	if (IS_ERR(cpuclk)) {
+		pr_debug("cpufreq: could not get CPU clk\n");
+		retval = PTR_ERR(cpuclk);
+		goto out_err;
+	}
+
+	min_freq = (clk_round_rate(cpuclk, 1) + 500) / 1000;
+	frequency = (clk_round_rate(cpuclk, ~0UL) + 500) / 1000;
+	policy->cpuinfo.transition_latency = 0;
+
+	/*
+	 * AVR32 CPU frequency rate scales in power of two between maximum and
+	 * minimum, also add space for the table end marker.
+	 *
+	 * Further validate that the frequency is usable, and append it to the
+	 * frequency table.
+	 */
+	steps = fls(frequency / min_freq) + 1;
+	freq_table = kzalloc(steps * sizeof(struct cpufreq_frequency_table),
+			GFP_KERNEL);
+	if (!freq_table) {
+		retval = -ENOMEM;
+		goto out_err_put_clk;
+	}
+
+	for (i = 0; i < (steps - 1); i++) {
+		rate = clk_round_rate(cpuclk, frequency * 1000) / 1000;
+
+		if (rate != frequency)
+			freq_table[i].frequency = CPUFREQ_ENTRY_INVALID;
+		else
+			freq_table[i].frequency = frequency;
+
+		frequency /= 2;
+	}
+
+	policy->clk = cpuclk;
+	freq_table[steps - 1].frequency = CPUFREQ_TABLE_END;
+
+	retval = cpufreq_table_validate_and_show(policy, freq_table);
+	if (!retval) {
+		printk("cpufreq: AT32AP CPU frequency driver\n");
+		return 0;
+	}
+
+	kfree(freq_table);
+out_err_put_clk:
+	clk_put(cpuclk);
+out_err:
+	return retval;
+}
+
+static struct cpufreq_driver at32_driver = {
+	.name		= "at32ap",
+	.init		= at32_cpufreq_driver_init,
+	.verify		= cpufreq_generic_frequency_table_verify,
+	.target_index	= at32_set_target,
+	.get		= cpufreq_generic_get,
+	.flags		= CPUFREQ_STICKY,
+};
+
+static int __init at32_cpufreq_init(void)
+{
+	return cpufreq_register_driver(&at32_driver);
+}
+late_initcall(at32_cpufreq_init);