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authorSudeep KarkadaNagesha <sudeep.karkadanagesha@arm.com>2013-10-29 12:18:39 +0000
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2013-10-30 00:48:26 +0100
commit47ac9aa165540b43deb3582f186073884de1cf3b (patch)
treeb191ae170496778588b34c8150015a7ac353d6a1 /drivers
parent4d910d5bb56c870e5a737b71d4130ec38dc4faea (diff)
downloadleg-kernel-47ac9aa165540b43deb3582f186073884de1cf3b.tar.gz
cpufreq: arm_big_little: add vexpress SPC interface driver
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>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/cpufreq/Kconfig.arm8
-rw-r--r--drivers/cpufreq/Makefile1
-rw-r--r--drivers/cpufreq/vexpress-spc-cpufreq.c70
3 files changed, 79 insertions, 0 deletions
diff --git a/drivers/cpufreq/Kconfig.arm b/drivers/cpufreq/Kconfig.arm
index 701ec95ce954..ce52ed949249 100644
--- a/drivers/cpufreq/Kconfig.arm
+++ b/drivers/cpufreq/Kconfig.arm
@@ -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.
diff --git a/drivers/cpufreq/Makefile b/drivers/cpufreq/Makefile
index b7948bbbbf1f..74945652dd7a 100644
--- a/drivers/cpufreq/Makefile
+++ b/drivers/cpufreq/Makefile
@@ -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
diff --git a/drivers/cpufreq/vexpress-spc-cpufreq.c b/drivers/cpufreq/vexpress-spc-cpufreq.c
new file mode 100644
index 000000000000..7f7c9c01b44e
--- /dev/null
+++ b/drivers/cpufreq/vexpress-spc-cpufreq.c
@@ -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");