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cpufreq: arm_big_little: add vexpress SPC interface driver

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The TC2(i.e. CA15_A7) Versatile Express has external Cortex M3 based
power controller which is responsible for CPU DVFS and SPC provides
the interface for the same.

This patch adds a tiny interface driver to check if OPPs are
initialised by SPC platform code and register the arm_big_little
cpufreq driver.

Signed-off-by: Sudeep KarkadaNagesha <sudeep.karkadanagesha@arm.com>
Acked-by: Nicolas Pitre <nico@linaro.org>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Sudeep KarkadaNagesha 2013-10-29 12:18:39 +00:00 committed by Rafael J. Wysocki
parent 4d910d5bb5
commit 47ac9aa165
3 changed files with 79 additions and 0 deletions
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8
drivers/cpufreq/Kconfig.arm
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@ -224,3 +224,11 @@ config ARM_TEGRA_CPUFREQ
default y
help
This adds the CPUFreq driver support for TEGRA SOCs.
config ARM_VEXPRESS_SPC_CPUFREQ
tristate "Versatile Express SPC based CPUfreq driver"
select ARM_BIG_LITTLE_CPUFREQ
depends on ARCH_VEXPRESS_SPC
help
This add the CPUfreq driver support for Versatile Express
big.LITTLE platforms using SPC for power management.

1
drivers/cpufreq/Makefile
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@ -74,6 +74,7 @@ obj-$(CONFIG_ARM_SA1100_CPUFREQ) += sa1100-cpufreq.o
obj-$(CONFIG_ARM_SA1110_CPUFREQ) += sa1110-cpufreq.o
obj-$(CONFIG_ARM_SPEAR_CPUFREQ) += spear-cpufreq.o
obj-$(CONFIG_ARM_TEGRA_CPUFREQ) += tegra-cpufreq.o
obj-$(CONFIG_ARM_VEXPRESS_SPC_CPUFREQ) += vexpress-spc-cpufreq.o
##################################################################################
# PowerPC platform drivers

70
drivers/cpufreq/vexpress-spc-cpufreq.c Normal file
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@ -0,0 +1,70 @@
/*
* Versatile Express SPC CPUFreq Interface driver
*
* It provides necessary ops to arm_big_little cpufreq driver.
*
* Copyright (C) 2013 ARM Ltd.
* Sudeep KarkadaNagesha <sudeep.karkadanagesha@arm.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.
*
* 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.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/cpufreq.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/pm_opp.h>
#include <linux/types.h>
#include "arm_big_little.h"
static int ve_spc_init_opp_table(struct device *cpu_dev)
{
/*
* platform specific SPC code must initialise the opp table
* so just check if the OPP count is non-zero
*/
return dev_pm_opp_get_opp_count(cpu_dev) <= 0;
}
static int ve_spc_get_transition_latency(struct device *cpu_dev)
{
return 1000000; /* 1 ms */
}
static struct cpufreq_arm_bL_ops ve_spc_cpufreq_ops = {
.name = "vexpress-spc",
.get_transition_latency = ve_spc_get_transition_latency,
.init_opp_table = ve_spc_init_opp_table,
};
static int ve_spc_cpufreq_probe(struct platform_device *pdev)
{
return bL_cpufreq_register(&ve_spc_cpufreq_ops);
}
static int ve_spc_cpufreq_remove(struct platform_device *pdev)
{
bL_cpufreq_unregister(&ve_spc_cpufreq_ops);
return 0;
}
static struct platform_driver ve_spc_cpufreq_platdrv = {
.driver = {
.name = "vexpress-spc-cpufreq",
.owner = THIS_MODULE,
},
.probe = ve_spc_cpufreq_probe,
.remove = ve_spc_cpufreq_remove,
};
module_platform_driver(ve_spc_cpufreq_platdrv);
MODULE_LICENSE("GPL");