linux/drivers/cpufreq/dbx500-cpufreq.c
Viresh Kumar d4019f0a92 cpufreq: move freq change notifications to cpufreq core
Most of the drivers do following in their ->target_index() routines:

	struct cpufreq_freqs freqs;
	freqs.old = old freq...
	freqs.new = new freq...

	cpufreq_notify_transition(policy, &freqs, CPUFREQ_PRECHANGE);

	/* Change rate here */

	cpufreq_notify_transition(policy, &freqs, CPUFREQ_POSTCHANGE);

This is replicated over all cpufreq drivers today and there doesn't exists a
good enough reason why this shouldn't be moved to cpufreq core instead.

There are few special cases though, like exynos5440, which doesn't do everything
on the call to ->target_index() routine and call some kind of bottom halves for
doing this work, work/tasklet/etc..

They may continue doing notification from their own code as flag:
CPUFREQ_ASYNC_NOTIFICATION is already set for them.

All drivers are also modified in this patch to avoid breaking 'git bisect', as
double notification would happen otherwise.

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: Stephen Warren <swarren@nvidia.com>
Tested-by: Andrew Lunn <andrew@lunn.ch>
Tested-by: Nicolas Pitre <nicolas.pitre@linaro.org>
Reviewed-by: Lan Tianyu <tianyu.lan@intel.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-10-31 00:11:08 +01:00

101 lines
2.6 KiB
C

/*
* Copyright (C) STMicroelectronics 2009
* Copyright (C) ST-Ericsson SA 2010-2012
*
* License Terms: GNU General Public License v2
* Author: Sundar Iyer <sundar.iyer@stericsson.com>
* Author: Martin Persson <martin.persson@stericsson.com>
* Author: Jonas Aaberg <jonas.aberg@stericsson.com>
*/
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/cpufreq.h>
#include <linux/delay.h>
#include <linux/slab.h>
#include <linux/platform_device.h>
#include <linux/clk.h>
static struct cpufreq_frequency_table *freq_table;
static struct clk *armss_clk;
static int dbx500_cpufreq_target(struct cpufreq_policy *policy,
unsigned int index)
{
/* update armss clk frequency */
return clk_set_rate(armss_clk, freq_table[index].frequency * 1000);
}
static unsigned int dbx500_cpufreq_getspeed(unsigned int cpu)
{
int i = 0;
unsigned long freq = clk_get_rate(armss_clk) / 1000;
/* The value is rounded to closest frequency in the defined table. */
while (freq_table[i + 1].frequency != CPUFREQ_TABLE_END) {
if (freq < freq_table[i].frequency +
(freq_table[i + 1].frequency - freq_table[i].frequency) / 2)
return freq_table[i].frequency;
i++;
}
return freq_table[i].frequency;
}
static int dbx500_cpufreq_init(struct cpufreq_policy *policy)
{
return cpufreq_generic_init(policy, freq_table, 20 * 1000);
}
static struct cpufreq_driver dbx500_cpufreq_driver = {
.flags = CPUFREQ_STICKY | CPUFREQ_CONST_LOOPS,
.verify = cpufreq_generic_frequency_table_verify,
.target_index = dbx500_cpufreq_target,
.get = dbx500_cpufreq_getspeed,
.init = dbx500_cpufreq_init,
.name = "DBX500",
.attr = cpufreq_generic_attr,
};
static int dbx500_cpufreq_probe(struct platform_device *pdev)
{
int i = 0;
freq_table = dev_get_platdata(&pdev->dev);
if (!freq_table) {
pr_err("dbx500-cpufreq: Failed to fetch cpufreq table\n");
return -ENODEV;
}
armss_clk = clk_get(&pdev->dev, "armss");
if (IS_ERR(armss_clk)) {
pr_err("dbx500-cpufreq: Failed to get armss clk\n");
return PTR_ERR(armss_clk);
}
pr_info("dbx500-cpufreq: Available frequencies:\n");
while (freq_table[i].frequency != CPUFREQ_TABLE_END) {
pr_info(" %d Mhz\n", freq_table[i].frequency/1000);
i++;
}
return cpufreq_register_driver(&dbx500_cpufreq_driver);
}
static struct platform_driver dbx500_cpufreq_plat_driver = {
.driver = {
.name = "cpufreq-ux500",
.owner = THIS_MODULE,
},
.probe = dbx500_cpufreq_probe,
};
static int __init dbx500_cpufreq_register(void)
{
return platform_driver_register(&dbx500_cpufreq_plat_driver);
}
device_initcall(dbx500_cpufreq_register);
MODULE_LICENSE("GPL v2");
MODULE_DESCRIPTION("cpufreq driver for DBX500");