Commit 6601b803 authored by Sekhar Nori's avatar Sekhar Nori Committed by Kevin Hilman
Browse files

davinci: add generic CPUFreq driver for DaVinci



Adds a basic CPUFreq driver for DaVinci devices registering with the
kernel CPUFreq infrastructure.

Support is added for both frequency and voltage regulation.

Signed-off-by: default avatarSekhar Nori <nsekhar@ti.com>
Signed-off-by: default avatarKevin Hilman <khilman@deeprootsystems.com>
parent a75fd514
......@@ -37,6 +37,7 @@ config ARCH_DAVINCI_DA850
bool "DA850/OMAP-L138 based system"
select CP_INTC
select ARCH_DAVINCI_DA8XX
select ARCH_HAS_CPUFREQ
config ARCH_DAVINCI_DA8XX
bool
......
......@@ -29,3 +29,6 @@ obj-$(CONFIG_MACH_DAVINCI_DM6467_EVM) += board-dm646x-evm.o
obj-$(CONFIG_MACH_DAVINCI_DM365_EVM) += board-dm365-evm.o
obj-$(CONFIG_MACH_DAVINCI_DA830_EVM) += board-da830-evm.o
obj-$(CONFIG_MACH_DAVINCI_DA850_EVM) += board-da850-evm.o
# Power Management
obj-$(CONFIG_CPU_FREQ) += cpufreq.o
/*
* CPU frequency scaling for DaVinci
*
* Copyright (C) 2009 Texas Instruments Incorporated - http://www.ti.com/
*
* Based on linux/arch/arm/plat-omap/cpu-omap.c. Original Copyright follows:
*
* Copyright (C) 2005 Nokia Corporation
* Written by Tony Lindgren <tony@atomide.com>
*
* Based on cpu-sa1110.c, Copyright (C) 2001 Russell King
*
* Copyright (C) 2007-2008 Texas Instruments, Inc.
* Updated to support OMAP3
* Rajendra Nayak <rnayak@ti.com>
*
* 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/cpufreq.h>
#include <linux/init.h>
#include <linux/err.h>
#include <linux/clk.h>
#include <linux/platform_device.h>
#include <mach/hardware.h>
#include <mach/cpufreq.h>
#include <mach/common.h>
#include "clock.h"
struct davinci_cpufreq {
struct device *dev;
struct clk *armclk;
};
static struct davinci_cpufreq cpufreq;
static int davinci_verify_speed(struct cpufreq_policy *policy)
{
struct davinci_cpufreq_config *pdata = cpufreq.dev->platform_data;
struct cpufreq_frequency_table *freq_table = pdata->freq_table;
struct clk *armclk = cpufreq.armclk;
if (freq_table)
return cpufreq_frequency_table_verify(policy, freq_table);
if (policy->cpu)
return -EINVAL;
cpufreq_verify_within_limits(policy, policy->cpuinfo.min_freq,
policy->cpuinfo.max_freq);
policy->min = clk_round_rate(armclk, policy->min * 1000) / 1000;
policy->max = clk_round_rate(armclk, policy->max * 1000) / 1000;
cpufreq_verify_within_limits(policy, policy->cpuinfo.min_freq,
policy->cpuinfo.max_freq);
return 0;
}
static unsigned int davinci_getspeed(unsigned int cpu)
{
if (cpu)
return 0;
return clk_get_rate(cpufreq.armclk) / 1000;
}
static int davinci_target(struct cpufreq_policy *policy,
unsigned int target_freq, unsigned int relation)
{
int ret = 0;
unsigned int idx;
struct cpufreq_freqs freqs;
struct davinci_cpufreq_config *pdata = cpufreq.dev->platform_data;
struct clk *armclk = cpufreq.armclk;
/*
* Ensure desired rate is within allowed range. Some govenors
* (ondemand) will just pass target_freq=0 to get the minimum.
*/
if (target_freq < policy->cpuinfo.min_freq)
target_freq = policy->cpuinfo.min_freq;
if (target_freq > policy->cpuinfo.max_freq)
target_freq = policy->cpuinfo.max_freq;
freqs.old = davinci_getspeed(0);
freqs.new = clk_round_rate(armclk, target_freq * 1000) / 1000;
freqs.cpu = 0;
if (freqs.old == freqs.new)
return ret;
cpufreq_debug_printk(CPUFREQ_DEBUG_DRIVER,
dev_driver_string(cpufreq.dev),
"transition: %u --> %u\n", freqs.old, freqs.new);
ret = cpufreq_frequency_table_target(policy, pdata->freq_table,
freqs.new, relation, &idx);
if (ret)
return -EINVAL;
cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
/* if moving to higher frequency, up the voltage beforehand */
if (pdata->set_voltage && freqs.new > freqs.old)
pdata->set_voltage(idx);
ret = clk_set_rate(armclk, idx);
/* if moving to lower freq, lower the voltage after lowering freq */
if (pdata->set_voltage && freqs.new < freqs.old)
pdata->set_voltage(idx);
cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
return ret;
}
static int __init davinci_cpu_init(struct cpufreq_policy *policy)
{
int result = 0;
struct davinci_cpufreq_config *pdata = cpufreq.dev->platform_data;
struct cpufreq_frequency_table *freq_table = pdata->freq_table;
if (policy->cpu != 0)
return -EINVAL;
policy->cur = policy->min = policy->max = davinci_getspeed(0);
if (freq_table) {
result = cpufreq_frequency_table_cpuinfo(policy, freq_table);
if (!result)
cpufreq_frequency_table_get_attr(freq_table,
policy->cpu);
} else {
policy->cpuinfo.min_freq = policy->min;
policy->cpuinfo.max_freq = policy->max;
}
policy->min = policy->cpuinfo.min_freq;
policy->max = policy->cpuinfo.max_freq;
policy->cur = davinci_getspeed(0);
/*
* Time measurement across the target() function yields ~1500-1800us
* time taken with no drivers on notification list.
* Setting the latency to 2000 us to accomodate addition of drivers
* to pre/post change notification list.
*/
policy->cpuinfo.transition_latency = 2000 * 1000;
return 0;
}
static int davinci_cpu_exit(struct cpufreq_policy *policy)
{
cpufreq_frequency_table_put_attr(policy->cpu);
return 0;
}
static struct freq_attr *davinci_cpufreq_attr[] = {
&cpufreq_freq_attr_scaling_available_freqs,
NULL,
};
static struct cpufreq_driver davinci_driver = {
.flags = CPUFREQ_STICKY,
.verify = davinci_verify_speed,
.target = davinci_target,
.get = davinci_getspeed,
.init = davinci_cpu_init,
.exit = davinci_cpu_exit,
.name = "davinci",
.attr = davinci_cpufreq_attr,
};
static int __init davinci_cpufreq_probe(struct platform_device *pdev)
{
struct davinci_cpufreq_config *pdata = pdev->dev.platform_data;
if (!pdata)
return -EINVAL;
if (!pdata->freq_table)
return -EINVAL;
cpufreq.dev = &pdev->dev;
cpufreq.armclk = clk_get(NULL, "arm");
if (IS_ERR(cpufreq.armclk)) {
dev_err(cpufreq.dev, "Unable to get ARM clock\n");
return PTR_ERR(cpufreq.armclk);
}
return cpufreq_register_driver(&davinci_driver);
}
static int __exit davinci_cpufreq_remove(struct platform_device *pdev)
{
clk_put(cpufreq.armclk);
return cpufreq_unregister_driver(&davinci_driver);
}
static struct platform_driver davinci_cpufreq_driver = {
.driver = {
.name = "cpufreq-davinci",
.owner = THIS_MODULE,
},
.remove = __exit_p(davinci_cpufreq_remove),
};
static int __init davinci_cpufreq_init(void)
{
return platform_driver_probe(&davinci_cpufreq_driver,
davinci_cpufreq_probe);
}
late_initcall(davinci_cpufreq_init);
/*
* TI DaVinci CPUFreq platform support.
*
* Copyright (C) 2009 Texas Instruments, Inc. http://www.ti.com/
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation version 2.
*
* This program is distributed "as is" WITHOUT ANY WARRANTY of any
* kind, whether express or implied; without even the implied warranty
* of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#ifndef _MACH_DAVINCI_CPUFREQ_H
#define _MACH_DAVINCI_CPUFREQ_H
#include <linux/cpufreq.h>
struct davinci_cpufreq_config {
struct cpufreq_frequency_table *freq_table;
int (*set_voltage) (unsigned int index);
};
#endif
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