linux/drivers/cpufreq/davinci-cpufreq.c

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/*
* 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_data/davinci-cpufreq.h>
#include <linux/platform_device.h>
#include <linux/export.h>
struct davinci_cpufreq {
struct device *dev;
struct clk *armclk;
struct clk *asyncclk;
unsigned long asyncrate;
};
static struct davinci_cpufreq cpufreq;
cpufreq: Implement light weight ->target_index() routine Currently, the prototype of cpufreq_drivers target routines is: int target(struct cpufreq_policy *policy, unsigned int target_freq, unsigned int relation); And most of the drivers call cpufreq_frequency_table_target() to get a valid index of their frequency table which is closest to the target_freq. And they don't use target_freq and relation after that. So, it makes sense to just do this work in cpufreq core before calling cpufreq_frequency_table_target() and simply pass index instead. But this can be done only with drivers which expose their frequency table with cpufreq core. For others we need to stick with the old prototype of target() until those drivers are converted to expose frequency tables. This patch implements the new light weight prototype for target_index() routine. It looks like this: int target_index(struct cpufreq_policy *policy, unsigned int index); CPUFreq core will call cpufreq_frequency_table_target() before calling this routine and pass index to it. Because CPUFreq core now requires to call routines present in freq_table.c CONFIG_CPU_FREQ_TABLE must be enabled all the time. This also marks target() interface as deprecated. So, that new drivers avoid using it. And Documentation is updated accordingly. It also converts existing .target() to newly defined light weight .target_index() routine for many driver. Acked-by: Hans-Christian Egtvedt <egtvedt@samfundet.no> Acked-by: Jesper Nilsson <jesper.nilsson@axis.com> Acked-by: Linus Walleij <linus.walleij@linaro.org> Acked-by: Russell King <linux@arm.linux.org.uk> Acked-by: David S. Miller <davem@davemloft.net> Tested-by: Andrew Lunn <andrew@lunn.ch> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rjw@rjwysocki.net>
2013-10-25 22:15:48 +08:00
static int davinci_target(struct cpufreq_policy *policy, unsigned int idx)
{
struct davinci_cpufreq_config *pdata = cpufreq.dev->platform_data;
struct clk *armclk = cpufreq.armclk;
unsigned int old_freq, new_freq;
int ret = 0;
old_freq = policy->cur;
new_freq = pdata->freq_table[idx].frequency;
/* if moving to higher frequency, up the voltage beforehand */
if (pdata->set_voltage && new_freq > old_freq) {
ret = pdata->set_voltage(idx);
if (ret)
return ret;
}
ret = clk_set_rate(armclk, new_freq * 1000);
if (ret)
return ret;
if (cpufreq.asyncclk) {
ret = clk_set_rate(cpufreq.asyncclk, cpufreq.asyncrate);
if (ret)
return ret;
}
/* if moving to lower freq, lower the voltage after lowering freq */
if (pdata->set_voltage && new_freq < old_freq)
pdata->set_voltage(idx);
return 0;
}
static int 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;
/* Finish platform specific initialization */
if (pdata->init) {
result = pdata->init();
if (result)
return result;
}
policy->clk = cpufreq.armclk;
/*
* Time measurement across the target() function yields ~1500-1800us
* time taken with no drivers on notification list.
* Setting the latency to 2000 us to accommodate addition of drivers
* to pre/post change notification list.
*/
return cpufreq_generic_init(policy, freq_table, 2000 * 1000);
}
static struct cpufreq_driver davinci_driver = {
.flags = CPUFREQ_STICKY | CPUFREQ_NEED_INITIAL_FREQ_CHECK,
.verify = cpufreq_generic_frequency_table_verify,
cpufreq: Implement light weight ->target_index() routine Currently, the prototype of cpufreq_drivers target routines is: int target(struct cpufreq_policy *policy, unsigned int target_freq, unsigned int relation); And most of the drivers call cpufreq_frequency_table_target() to get a valid index of their frequency table which is closest to the target_freq. And they don't use target_freq and relation after that. So, it makes sense to just do this work in cpufreq core before calling cpufreq_frequency_table_target() and simply pass index instead. But this can be done only with drivers which expose their frequency table with cpufreq core. For others we need to stick with the old prototype of target() until those drivers are converted to expose frequency tables. This patch implements the new light weight prototype for target_index() routine. It looks like this: int target_index(struct cpufreq_policy *policy, unsigned int index); CPUFreq core will call cpufreq_frequency_table_target() before calling this routine and pass index to it. Because CPUFreq core now requires to call routines present in freq_table.c CONFIG_CPU_FREQ_TABLE must be enabled all the time. This also marks target() interface as deprecated. So, that new drivers avoid using it. And Documentation is updated accordingly. It also converts existing .target() to newly defined light weight .target_index() routine for many driver. Acked-by: Hans-Christian Egtvedt <egtvedt@samfundet.no> Acked-by: Jesper Nilsson <jesper.nilsson@axis.com> Acked-by: Linus Walleij <linus.walleij@linaro.org> Acked-by: Russell King <linux@arm.linux.org.uk> Acked-by: David S. Miller <davem@davemloft.net> Tested-by: Andrew Lunn <andrew@lunn.ch> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rjw@rjwysocki.net>
2013-10-25 22:15:48 +08:00
.target_index = davinci_target,
.get = cpufreq_generic_get,
.init = davinci_cpu_init,
.name = "davinci",
.attr = cpufreq_generic_attr,
};
static int __init davinci_cpufreq_probe(struct platform_device *pdev)
{
struct davinci_cpufreq_config *pdata = pdev->dev.platform_data;
struct clk *asyncclk;
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);
}
asyncclk = clk_get(cpufreq.dev, "async");
if (!IS_ERR(asyncclk)) {
cpufreq.asyncclk = asyncclk;
cpufreq.asyncrate = clk_get_rate(asyncclk);
}
return cpufreq_register_driver(&davinci_driver);
}
static int __exit davinci_cpufreq_remove(struct platform_device *pdev)
{
clk_put(cpufreq.armclk);
if (cpufreq.asyncclk)
clk_put(cpufreq.asyncclk);
return cpufreq_unregister_driver(&davinci_driver);
}
static struct platform_driver davinci_cpufreq_driver = {
.driver = {
.name = "cpufreq-davinci",
},
.remove = __exit_p(davinci_cpufreq_remove),
};
int __init davinci_cpufreq_init(void)
{
return platform_driver_probe(&davinci_cpufreq_driver,
davinci_cpufreq_probe);
}