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Commit ec6bced6 authored by Tony Lindgren's avatar Tony Lindgren Committed by Russell King
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[PATCH] ARM: 2803/1: OMAP update 11/11: Add cpufreq support 



Patch from Tony Lindgren

This patch adds minimal cpufreq support for OMAP
taking advantage of the clock framework.

Signed-off-by: default avatarTony Lindgren <tony@atomide.com>
Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
parent d3b83419

arch/arm/Kconfig

+1 −1
Original line number Diff line number Diff line
@@ -516,7 +516,7 @@ config XIP_PHYS_ADDR 


endmenu



if (ARCH_SA1100 || ARCH_INTEGRATOR)

if (ARCH_SA1100 || ARCH_INTEGRATOR || ARCH_OMAP1)



menu "CPU Frequency scaling"

arch/arm/plat-omap/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -14,3 +14,4 @@ obj-$(CONFIG_ARCH_OMAP16XX) += ocpi.o 
# Power Management

obj-$(CONFIG_PM) += pm.o sleep.o



obj-$(CONFIG_CPU_FREQ) += cpu-omap.o

arch/arm/plat-omap/cpu-omap.c

0 → 100644
+128 −0
Original line number Diff line number Diff line 
/*

 *  linux/arch/arm/plat-omap/cpu-omap.c

 *

 *  CPU frequency scaling for OMAP

 *

 *  Copyright (C) 2005 Nokia Corporation

 *  Written by Tony Lindgren <tony@atomide.com>

 *

 *  Based on cpu-sa1110.c, Copyright (C) 2001 Russell King

 *

 * 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.

 */

#include <linux/types.h>

#include <linux/kernel.h>

#include <linux/sched.h>

#include <linux/cpufreq.h>

#include <linux/delay.h>

#include <linux/init.h>

#include <linux/err.h>



#include <asm/hardware.h>

#include <asm/mach-types.h>

#include <asm/io.h>

#include <asm/system.h>



#include <asm/hardware/clock.h>



/* TODO: Add support for SDRAM timing changes */



int omap_verify_speed(struct cpufreq_policy *policy)

{

	struct clk * mpu_clk;



	if (policy->cpu)

		return -EINVAL;



	cpufreq_verify_within_limits(policy, policy->cpuinfo.min_freq,

				     policy->cpuinfo.max_freq);

	mpu_clk = clk_get(NULL, "mpu");

	if (IS_ERR(mpu_clk))

		return PTR_ERR(mpu_clk);

	policy->min = clk_round_rate(mpu_clk, policy->min * 1000) / 1000;

	policy->max = clk_round_rate(mpu_clk, policy->max * 1000) / 1000;

	cpufreq_verify_within_limits(policy, policy->cpuinfo.min_freq,

				     policy->cpuinfo.max_freq);

	clk_put(mpu_clk);



	return 0;

}



unsigned int omap_getspeed(unsigned int cpu)

{

	struct clk * mpu_clk;

	unsigned long rate;



	if (cpu)

		return 0;



	mpu_clk = clk_get(NULL, "mpu");

	if (IS_ERR(mpu_clk))

		return 0;

	rate = clk_get_rate(mpu_clk) / 1000;

	clk_put(mpu_clk);



	return rate;

}



static int omap_target(struct cpufreq_policy *policy,

		       unsigned int target_freq,

		       unsigned int relation)

{

	struct clk * mpu_clk;

	struct cpufreq_freqs freqs;

	int ret = 0;



	mpu_clk = clk_get(NULL, "mpu");

	if (IS_ERR(mpu_clk))

		return PTR_ERR(mpu_clk);



	freqs.old = omap_getspeed(0);

	freqs.new = clk_round_rate(mpu_clk, target_freq * 1000) / 1000;

	freqs.cpu = 0;



	cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);

	ret = clk_set_rate(mpu_clk, target_freq * 1000);

	cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);

	clk_put(mpu_clk);



	return ret;

}



static int __init omap_cpu_init(struct cpufreq_policy *policy)

{

	struct clk * mpu_clk;



	mpu_clk = clk_get(NULL, "mpu");

	if (IS_ERR(mpu_clk))

		return PTR_ERR(mpu_clk);



	if (policy->cpu != 0)

		return -EINVAL;

	policy->cur = policy->min = policy->max = omap_getspeed(0);

	policy->governor = CPUFREQ_DEFAULT_GOVERNOR;

	policy->cpuinfo.min_freq = clk_round_rate(mpu_clk, 0) / 1000;

	policy->cpuinfo.max_freq = clk_round_rate(mpu_clk, 216000000) / 1000;

	policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL;

	clk_put(mpu_clk);



	return 0;

}



static struct cpufreq_driver omap_driver = {

	.flags		= CPUFREQ_STICKY,

	.verify		= omap_verify_speed,

	.target		= omap_target,

	.get		= omap_getspeed,

	.init		= omap_cpu_init,

	.name		= "omap",

};



static int __init omap_cpufreq_init(void)

{

	return cpufreq_register_driver(&omap_driver);

}



arch_initcall(omap_cpufreq_init);