cpufreq: hisilicon: add acpu driver

Add acpu driver for hisilicon SoC, acpu is application processor
subsystem. Currently the acpu has the coupled clock domain for two
clusters, so this driver will directly use cpufreq-dt driver as
backend.

Signed-off-by: Leo Yan <leo.yan@linaro.org>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/cpufreq/Kconfig.arm

@@ -108,6 +108,15 @@ config ARM_HIGHBANK_CPUFREQ
 
 	  If in doubt, say N.
 
+config ARM_HISI_ACPU_CPUFREQ
+	tristate "Hisilicon ACPU CPUfreq driver"
+	depends on ARCH_HISI && CPUFREQ_DT
+	select PM_OPP
+	help
+	  This enables the hisilicon ACPU CPUfreq driver.
+
+	  If in doubt, say N.
+
 config ARM_IMX6Q_CPUFREQ
 	tristate "Freescale i.MX6 cpufreq support"
 	depends on ARCH_MXC

drivers/cpufreq/Makefile

@@ -59,6 +59,7 @@ arm-exynos-cpufreq-$(CONFIG_ARM_EXYNOS4X12_CPUFREQ)	+= exynos4x12-cpufreq.o
 arm-exynos-cpufreq-$(CONFIG_ARM_EXYNOS5250_CPUFREQ)	+= exynos5250-cpufreq.o
 obj-$(CONFIG_ARM_EXYNOS5440_CPUFREQ)	+= exynos5440-cpufreq.o
 obj-$(CONFIG_ARM_HIGHBANK_CPUFREQ)	+= highbank-cpufreq.o
+obj-$(CONFIG_ARM_HISI_ACPU_CPUFREQ)	+= hisi-acpu-cpufreq.o
 obj-$(CONFIG_ARM_IMX6Q_CPUFREQ)		+= imx6q-cpufreq.o
 obj-$(CONFIG_ARM_INTEGRATOR)		+= integrator-cpufreq.o
 obj-$(CONFIG_ARM_KIRKWOOD_CPUFREQ)	+= kirkwood-cpufreq.o

drivers/cpufreq/hisi-acpu-cpufreq.c

@@ -0,0 +1,42 @@
+/*
+ * Hisilicon Platforms Using ACPU CPUFreq Support
+ *
+ * Copyright (c) 2015 Hisilicon Limited.
+ * Copyright (c) 2015 Linaro Limited.
+ *
+ * Leo Yan <leo.yan@linaro.org>
+ *
+ * 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/err.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+
+static int __init hisi_acpu_cpufreq_driver_init(void)
+{
+	struct platform_device *pdev;
+
+	if (!of_machine_is_compatible("hisilicon,hi6220"))
+		return -ENODEV;
+
+	pdev = platform_device_register_simple("cpufreq-dt", -1, NULL, 0);
+	return PTR_ERR_OR_ZERO(pdev);
+}
+module_init(hisi_acpu_cpufreq_driver_init);
+
+MODULE_AUTHOR("Leo Yan <leo.yan@linaro.org>");
+MODULE_DESCRIPTION("Hisilicon acpu cpufreq driver");
+MODULE_LICENSE("GPL v2");