cpufreq: AVR32: move cpufreq driver to drivers/cpufreq

This patch moves cpufreq driver of AVR32 based at32ap platform to
drivers/cpufreq.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Hans-Christian Egtvedt <egtvedt@samfundet.no>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

3 files changed, 140 insertions, 0 deletions

diff --git a/drivers/cpufreq/Kconfig b/drivers/cpufreq/Kconfig
index cbcb21e..d7ce6cc 100644
--- a/drivers/cpufreq/Kconfig
+++ b/drivers/cpufreq/Kconfig
@@ -205,6 +205,19 @@ depends on ARM
 source "drivers/cpufreq/Kconfig.arm"
 endmenu
 
+menu "AVR32 CPU frequency scaling drivers"
+depends on AVR32
+
+config AVR32_AT32AP_CPUFREQ
+	bool "CPU frequency driver for AT32AP"
+	depends on PLATFORM_AT32AP
+	default n
+	help
+	  This enables the CPU frequency driver for AT32AP processors.
+	  If in doubt, say N.
+
+endmenu
+
 menu "PowerPC CPU frequency scaling drivers"
 depends on PPC32 || PPC64
 source "drivers/cpufreq/Kconfig.powerpc"
diff --git a/drivers/cpufreq/Makefile b/drivers/cpufreq/Makefile
index 8b21016..2701aca 100644
--- a/drivers/cpufreq/Makefile
+++ b/drivers/cpufreq/Makefile
@@ -74,3 +74,7 @@ obj-$(CONFIG_ARCH_TEGRA)		+= tegra-cpufreq.o
 ##################################################################################
 # PowerPC platform drivers
 obj-$(CONFIG_CPU_FREQ_MAPLE)		+= maple-cpufreq.o
+
+##################################################################################
+# Other platform drivers
+obj-$(CONFIG_AVR32_AT32AP_CPUFREQ)	+= at32ap-cpufreq.o
diff --git a/drivers/cpufreq/at32ap-cpufreq.c b/drivers/cpufreq/at32ap-cpufreq.c
new file mode 100644
index 0000000..6544887
--- /dev/null
+++ b/drivers/cpufreq/at32ap-cpufreq.c
@@ -0,0 +1,123 @@
+/*
+ * 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>
+
+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 unsigned int	ref_freq;
+static unsigned long	loops_per_jiffy_ref;
+
+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.flags = 0;
+
+	if (!ref_freq) {
+		ref_freq = freqs.old;
+		loops_per_jiffy_ref = boot_cpu_data.loops_per_jiffy;
+	}
+
+	cpufreq_notify_transition(policy, &freqs, CPUFREQ_PRECHANGE);
+	if (freqs.old < freqs.new)
+		boot_cpu_data.loops_per_jiffy = cpufreq_scale(
+				loops_per_jiffy_ref, ref_freq, freqs.new);
+	clk_set_rate(cpuclk, freq);
+	if (freqs.new < freqs.old)
+		boot_cpu_data.loops_per_jiffy = cpufreq_scale(
+				loops_per_jiffy_ref, ref_freq, freqs.new);
+	cpufreq_notify_transition(policy, &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;
+
+	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);
+}
+late_initcall(at32_cpufreq_init);