[PATCH v2 4/5] cpufreq: arm_big_little: add vexpress SPC interface driver
From: Sudeep KarkadaNagesha <hidden>
Date: 2013-10-21 09:58:53
Also in:
linux-pm
Subsystem:
cpu frequency drivers - vexpress spc arm big little, cpu frequency scaling framework, the rest · Maintainers:
Viresh Kumar, Sudeep Holla, "Rafael J. Wysocki", Linus Torvalds
From: Sudeep KarkadaNagesha <redacted> 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 <redacted> Acked-by: Nicolas Pitre <redacted> Cc: Viresh Kumar <viresh.kumar@linaro.org> --- drivers/cpufreq/Kconfig.arm | 8 ++++ drivers/cpufreq/Makefile | 1 + drivers/cpufreq/vexpress-spc-cpufreq.c | 69 ++++++++++++++++++++++++++++++++++ 3 files changed, 78 insertions(+) create mode 100644 drivers/cpufreq/vexpress-spc-cpufreq.c
diff --git a/drivers/cpufreq/Kconfig.arm b/drivers/cpufreq/Kconfig.arm
index 0fa204b..db4bc2d 100644
--- a/drivers/cpufreq/Kconfig.arm
+++ b/drivers/cpufreq/Kconfig.arm@@ -235,3 +235,11 @@ 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.
diff --git a/drivers/cpufreq/Makefile b/drivers/cpufreq/Makefile
index ad5866c..a1c390f 100644
--- a/drivers/cpufreq/Makefile
+++ b/drivers/cpufreq/Makefile@@ -77,6 +77,7 @@ 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
diff --git a/drivers/cpufreq/vexpress-spc-cpufreq.c b/drivers/cpufreq/vexpress-spc-cpufreq.c
new file mode 100644
index 0000000..f0508bf
--- /dev/null
+++ b/drivers/cpufreq/vexpress-spc-cpufreq.c@@ -0,0 +1,69 @@ +/* + * 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/opp.h> +#include <linux/module.h> +#include <linux/platform_device.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 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");
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1.8.1.2