[v2,1/2] cpufreq: Add sunxi nvmem based CPU scaling driver
diff mbox series

Message ID 20190409172558.18778-2-tiny.windzz@gmail.com
State New
Headers show
Series
  • cpufreq: Add sunxi nvmem based CPU scaling driver
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Commit Message

Frank Lee April 9, 2019, 5:25 p.m. UTC
For some SoCs, the CPU frequency subset and voltage value of each OPP
varies based on the silicon variant in use. The sunxi-cpufreq-nvmem
driver reads the efuse value from the SoC to provide the OPP framework
with required information.

Signed-off-by: Yangtao Li <tiny.windzz@gmail.com>
---
 MAINTAINERS                           |   7 +
 drivers/cpufreq/Kconfig.arm           |  10 ++
 drivers/cpufreq/Makefile              |   1 +
 drivers/cpufreq/cpufreq-dt-platdev.c  |   2 +
 drivers/cpufreq/sunxi-cpufreq-nvmem.c | 234 ++++++++++++++++++++++++++
 5 files changed, 254 insertions(+)
 create mode 100644 drivers/cpufreq/sunxi-cpufreq-nvmem.c

Comments

Viresh Kumar April 10, 2019, 3:24 a.m. UTC | #1
On 09-04-19, 13:25, Yangtao Li wrote:
> +static const struct sunxi_cpufreq_soc_data sun50i_h6_data = {
> +	.efuse_xlate = sun50i_efuse_xlate,
> +	.nvmem_mask = 0x7,
> +	.nvmem_shift = 5,
> +};
> +
> +static const struct of_device_id sunxi_cpufreq_match_list[] = {
> +	{ .compatible = "allwinner,sun50i-h6", .data = &sun50i_h6_data },
> +	{}
> +};
> +
> +static const struct of_device_id *sunxi_cpufreq_match_node(void)
> +{
> +	struct device_node *np;
> +	const struct of_device_id *match;
> +
> +	np = of_find_node_by_path("/");
> +	match = of_match_node(sunxi_cpufreq_match_list, np);
> +	of_node_put(np);
> +
> +	return match;
> +}
> +

Above code can be placed just above sunxi_cpufreq_init(), if you ...

> +static int sunxi_cpufreq_nvmem_probe(struct platform_device *pdev)
> +{
> +	const struct sunxi_cpufreq_soc_data *soc_data;
> +	struct opp_table **opp_tables;
> +	const struct of_device_id *match;
> +	char name[MAX_NAME_LEN];
> +	unsigned int cpu;
> +	u32 speed = 0;
> +	int ret;
> +
> +	opp_tables = kcalloc(num_possible_cpus(), sizeof(*opp_tables),
> +			     GFP_KERNEL);
> +	if (!opp_tables)
> +		return -ENOMEM;
> +
> +	match = sunxi_cpufreq_match_node();

... avoid this and ...

> +	soc_data = match->data;
> +	if (!soc_data)
> +		return -EINVAL;
> +
> +	ret = sunxi_cpufreq_get_efuse(soc_data, &speed);
> +	if (ret)
> +		return ret;
> +
> +	snprintf(name, MAX_NAME_LEN, "speed%d", speed);
> +
> +	for_each_possible_cpu(cpu) {
> +		struct device *cpu_dev = get_cpu_device(cpu);
> +
> +		if (NULL == cpu_dev) {
> +			ret = -ENODEV;
> +			goto free_opp;
> +		}
> +
> +		opp_tables[cpu] = dev_pm_opp_set_prop_name(cpu_dev, name);
> +		if (IS_ERR(opp_tables[cpu])) {
> +			ret = PTR_ERR(opp_tables[cpu]);
> +			pr_err("Failed to set prop name\n");
> +			goto free_opp;
> +		}
> +	}
> +
> +	cpufreq_dt_pdev = platform_device_register_simple("cpufreq-dt", -1,
> +							  NULL, 0);
> +	if (!IS_ERR(cpufreq_dt_pdev)) {
> +		platform_set_drvdata(pdev, opp_tables);
> +		return 0;
> +	}
> +
> +	ret = PTR_ERR(cpufreq_dt_pdev);
> +	pr_err("Failed to register platform device\n");
> +
> +free_opp:
> +	for_each_possible_cpu(cpu) {
> +		if (IS_ERR_OR_NULL(opp_tables[cpu]))
> +			break;
> +		dev_pm_opp_put_prop_name(opp_tables[cpu]);
> +	}
> +	kfree(opp_tables);
> +
> +	return ret;
> +}
> +
> +static int sunxi_cpufreq_nvmem_remove(struct platform_device *pdev)
> +{
> +	struct opp_table **opp_tables = platform_get_drvdata(pdev);
> +	unsigned int cpu;
> +
> +	platform_device_unregister(cpufreq_dt_pdev);
> +
> +	for_each_possible_cpu(cpu)
> +		dev_pm_opp_put_prop_name(opp_tables[cpu]);
> +
> +	kfree(opp_tables);
> +
> +	return 0;
> +}
> +
> +static struct platform_driver sunxi_cpufreq_driver = {
> +	.probe = sunxi_cpufreq_nvmem_probe,
> +	.remove = sunxi_cpufreq_nvmem_remove,
> +	.driver = {
> +		.name = "sunxi-cpufreq-nvmem",
> +	},
> +};
> +
> +/*
> + * Since the driver depends on nvmem drivers, which may return EPROBE_DEFER,
> + * all the real activity is done in the probe, which may be defered as well.
> + * The init here is only registering the driver and the platform device.
> + */
> +static int __init sunxi_cpufreq_init(void)
> +{
> +	const struct of_device_id *match;
> +	int ret;
> +
> +	match = sunxi_cpufreq_match_node();
> +	if (!match)
> +		return -ENODEV;
> +
> +	ret = platform_driver_register(&sunxi_cpufreq_driver);
> +	if (unlikely(ret < 0))
> +		return ret;
> +
> +	sunxi_cpufreq_pdev = platform_device_register_simple(
> +		"sunxi-cpufreq-nvmem", -1, NULL, 0);

... pass match->data as platform device's data here..

> +	ret = PTR_ERR_OR_ZERO(sunxi_cpufreq_pdev);
> +	if (0 == ret)
> +		return 0;
> +
> +	platform_driver_unregister(&sunxi_cpufreq_driver);
> +	return ret;
> +}
> +module_init(sunxi_cpufreq_init);
> +
> +static void __exit sunxi_cpufreq_exit(void)
> +{
> +	platform_device_unregister(sunxi_cpufreq_pdev);
> +	platform_driver_unregister(&sunxi_cpufreq_driver);
> +}
> +module_exit(sunxi_cpufreq_exit);
> +
> +MODULE_DESCRIPTION("Sunxi cpufreq driver");
> +MODULE_LICENSE("GPL v2");
> -- 
> 2.17.0
Frank Lee April 10, 2019, 5:44 p.m. UTC | #2
On Wed, Apr 10, 2019 at 11:24 AM Viresh Kumar <viresh.kumar@linaro.org> wrote:
>
> On 09-04-19, 13:25, Yangtao Li wrote:
> > +static const struct sunxi_cpufreq_soc_data sun50i_h6_data = {
> > +     .efuse_xlate = sun50i_efuse_xlate,
> > +     .nvmem_mask = 0x7,
> > +     .nvmem_shift = 5,
> > +};
> > +
> > +static const struct of_device_id sunxi_cpufreq_match_list[] = {
> > +     { .compatible = "allwinner,sun50i-h6", .data = &sun50i_h6_data },
> > +     {}
> > +};
> > +
> > +static const struct of_device_id *sunxi_cpufreq_match_node(void)
> > +{
> > +     struct device_node *np;
> > +     const struct of_device_id *match;
> > +
> > +     np = of_find_node_by_path("/");
> > +     match = of_match_node(sunxi_cpufreq_match_list, np);
> > +     of_node_put(np);
> > +
> > +     return match;
> > +}
> > +
>
> Above code can be placed just above sunxi_cpufreq_init(), if you ...
>
> > +static int sunxi_cpufreq_nvmem_probe(struct platform_device *pdev)
> > +{
> > +     const struct sunxi_cpufreq_soc_data *soc_data;
> > +     struct opp_table **opp_tables;
> > +     const struct of_device_id *match;
> > +     char name[MAX_NAME_LEN];
> > +     unsigned int cpu;
> > +     u32 speed = 0;
> > +     int ret;
> > +
> > +     opp_tables = kcalloc(num_possible_cpus(), sizeof(*opp_tables),
> > +                          GFP_KERNEL);
> > +     if (!opp_tables)
> > +             return -ENOMEM;
> > +
> > +     match = sunxi_cpufreq_match_node();
>
> ... avoid this and ...
>
> > +     soc_data = match->data;
> > +     if (!soc_data)
> > +             return -EINVAL;
> > +
> > +     ret = sunxi_cpufreq_get_efuse(soc_data, &speed);
> > +     if (ret)
> > +             return ret;
> > +
> > +     snprintf(name, MAX_NAME_LEN, "speed%d", speed);
> > +
> > +     for_each_possible_cpu(cpu) {
> > +             struct device *cpu_dev = get_cpu_device(cpu);
> > +
> > +             if (NULL == cpu_dev) {
> > +                     ret = -ENODEV;
> > +                     goto free_opp;
> > +             }
> > +
> > +             opp_tables[cpu] = dev_pm_opp_set_prop_name(cpu_dev, name);
> > +             if (IS_ERR(opp_tables[cpu])) {
> > +                     ret = PTR_ERR(opp_tables[cpu]);
> > +                     pr_err("Failed to set prop name\n");
> > +                     goto free_opp;
> > +             }
> > +     }
> > +
> > +     cpufreq_dt_pdev = platform_device_register_simple("cpufreq-dt", -1,
> > +                                                       NULL, 0);
> > +     if (!IS_ERR(cpufreq_dt_pdev)) {
> > +             platform_set_drvdata(pdev, opp_tables);
> > +             return 0;
> > +     }
> > +
> > +     ret = PTR_ERR(cpufreq_dt_pdev);
> > +     pr_err("Failed to register platform device\n");
> > +
> > +free_opp:
> > +     for_each_possible_cpu(cpu) {
> > +             if (IS_ERR_OR_NULL(opp_tables[cpu]))
> > +                     break;
> > +             dev_pm_opp_put_prop_name(opp_tables[cpu]);
> > +     }
> > +     kfree(opp_tables);
> > +
> > +     return ret;
> > +}
> > +
> > +static int sunxi_cpufreq_nvmem_remove(struct platform_device *pdev)
> > +{
> > +     struct opp_table **opp_tables = platform_get_drvdata(pdev);
> > +     unsigned int cpu;
> > +
> > +     platform_device_unregister(cpufreq_dt_pdev);
> > +
> > +     for_each_possible_cpu(cpu)
> > +             dev_pm_opp_put_prop_name(opp_tables[cpu]);
> > +
> > +     kfree(opp_tables);
> > +
> > +     return 0;
> > +}
> > +
> > +static struct platform_driver sunxi_cpufreq_driver = {
> > +     .probe = sunxi_cpufreq_nvmem_probe,
> > +     .remove = sunxi_cpufreq_nvmem_remove,
> > +     .driver = {
> > +             .name = "sunxi-cpufreq-nvmem",
> > +     },
> > +};
> > +
> > +/*
> > + * Since the driver depends on nvmem drivers, which may return EPROBE_DEFER,
> > + * all the real activity is done in the probe, which may be defered as well.
> > + * The init here is only registering the driver and the platform device.
> > + */
> > +static int __init sunxi_cpufreq_init(void)
> > +{
> > +     const struct of_device_id *match;
> > +     int ret;
> > +
> > +     match = sunxi_cpufreq_match_node();
> > +     if (!match)
> > +             return -ENODEV;
> > +
> > +     ret = platform_driver_register(&sunxi_cpufreq_driver);
> > +     if (unlikely(ret < 0))
> > +             return ret;
> > +
> > +     sunxi_cpufreq_pdev = platform_device_register_simple(
> > +             "sunxi-cpufreq-nvmem", -1, NULL, 0);
>
> ... pass match->data as platform device's data here..
Yead, it is.

Thanks,
Yangtao
>
> > +     ret = PTR_ERR_OR_ZERO(sunxi_cpufreq_pdev);
> > +     if (0 == ret)
> > +             return 0;
> > +
> > +     platform_driver_unregister(&sunxi_cpufreq_driver);
> > +     return ret;
> > +}
> > +module_init(sunxi_cpufreq_init);
> > +
> > +static void __exit sunxi_cpufreq_exit(void)
> > +{
> > +     platform_device_unregister(sunxi_cpufreq_pdev);
> > +     platform_driver_unregister(&sunxi_cpufreq_driver);
> > +}
> > +module_exit(sunxi_cpufreq_exit);
> > +
> > +MODULE_DESCRIPTION("Sunxi cpufreq driver");
> > +MODULE_LICENSE("GPL v2");
> > --
> > 2.17.0
>
> --
> viresh

Patch
diff mbox series

diff --git a/MAINTAINERS b/MAINTAINERS
index 391405091c6b..bfd18ba6aa1a 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -667,6 +667,13 @@  S:	Maintained
 F:	Documentation/i2c/busses/i2c-ali1563
 F:	drivers/i2c/busses/i2c-ali1563.c
 
+ALLWINNER CPUFREQ DRIVER
+M:	Yangtao Li <tiny.windzz@gmail.com>
+L:	linux-pm@vger.kernel.org
+S:	Maintained
+F:	Documentation/devicetree/bindings/opp/sunxi-nvmem-cpufreq.txt
+F:	drivers/cpufreq/sunxi-cpufreq-nvmem.c
+
 ALLWINNER SECURITY SYSTEM
 M:	Corentin Labbe <clabbe.montjoie@gmail.com>
 L:	linux-crypto@vger.kernel.org
diff --git a/drivers/cpufreq/Kconfig.arm b/drivers/cpufreq/Kconfig.arm
index 179a1d302f48..25933c4321a7 100644
--- a/drivers/cpufreq/Kconfig.arm
+++ b/drivers/cpufreq/Kconfig.arm
@@ -18,6 +18,16 @@  config ACPI_CPPC_CPUFREQ
 
 	  If in doubt, say N.
 
+config ARM_ALLWINNER_CPUFREQ_NVMEM
+	tristate "Allwinner nvmem based CPUFreq"
+	depends on ARCH_SUNXI
+	depends on NVMEM_SUNXI_SID
+	select PM_OPP
+	help
+	  This adds the CPUFreq driver for Allwinner nvmem based SoC.
+
+	  If in doubt, say N.
+
 config ARM_ARMADA_37XX_CPUFREQ
 	tristate "Armada 37xx CPUFreq support"
 	depends on ARCH_MVEBU && CPUFREQ_DT
diff --git a/drivers/cpufreq/Makefile b/drivers/cpufreq/Makefile
index 689b26c6f949..da28de67613c 100644
--- a/drivers/cpufreq/Makefile
+++ b/drivers/cpufreq/Makefile
@@ -78,6 +78,7 @@  obj-$(CONFIG_ARM_SCMI_CPUFREQ)		+= scmi-cpufreq.o
 obj-$(CONFIG_ARM_SCPI_CPUFREQ)		+= scpi-cpufreq.o
 obj-$(CONFIG_ARM_SPEAR_CPUFREQ)		+= spear-cpufreq.o
 obj-$(CONFIG_ARM_STI_CPUFREQ)		+= sti-cpufreq.o
+obj-$(CONFIG_ARM_ALLWINNER_CPUFREQ_NVMEM) += sunxi-cpufreq-nvmem.o
 obj-$(CONFIG_ARM_TANGO_CPUFREQ)		+= tango-cpufreq.o
 obj-$(CONFIG_ARM_TEGRA20_CPUFREQ)	+= tegra20-cpufreq.o
 obj-$(CONFIG_ARM_TEGRA124_CPUFREQ)	+= tegra124-cpufreq.o
diff --git a/drivers/cpufreq/cpufreq-dt-platdev.c b/drivers/cpufreq/cpufreq-dt-platdev.c
index 47729a22c159..50e7810f3a28 100644
--- a/drivers/cpufreq/cpufreq-dt-platdev.c
+++ b/drivers/cpufreq/cpufreq-dt-platdev.c
@@ -105,6 +105,8 @@  static const struct of_device_id whitelist[] __initconst = {
  * platforms using "operating-points-v2" property.
  */
 static const struct of_device_id blacklist[] __initconst = {
+	{ .compatible = "allwinner,sun50i-h6", },
+
 	{ .compatible = "calxeda,highbank", },
 	{ .compatible = "calxeda,ecx-2000", },
 
diff --git a/drivers/cpufreq/sunxi-cpufreq-nvmem.c b/drivers/cpufreq/sunxi-cpufreq-nvmem.c
new file mode 100644
index 000000000000..a72caac572c4
--- /dev/null
+++ b/drivers/cpufreq/sunxi-cpufreq-nvmem.c
@@ -0,0 +1,234 @@ 
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Allwinner CPUFreq nvmem based driver
+ *
+ * The sunxi-cpufreq-nvmem driver reads the efuse value from the SoC to
+ * provide the OPP framework with required information.
+ *
+ * Copyright (C) 2019 Yangtao Li <tiny.windzz@gmail.com>
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/module.h>
+#include <linux/nvmem-consumer.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/pm_opp.h>
+#include <linux/slab.h>
+
+#define MAX_NAME_LEN      7
+
+struct sunxi_cpufreq_soc_data {
+	u32 (*efuse_xlate)(const struct sunxi_cpufreq_soc_data *soc_data,
+			   u32 efuse);
+	u32 nvmem_mask;
+	u32 nvmem_shift;
+};
+
+static struct platform_device *cpufreq_dt_pdev, *sunxi_cpufreq_pdev;
+
+static u32 sun50i_efuse_xlate(const struct sunxi_cpufreq_soc_data *soc_data,
+			      u32 efuse)
+{
+	return (efuse >> soc_data->nvmem_shift) & soc_data->nvmem_mask;
+}
+
+/**
+ * sunxi_cpufreq_get_efuse() - Parse and return efuse value present on SoC
+ * @soc_data: Pointer to sunxi_cpufreq_soc_data context
+ * @versions: Set to the value parsed from efuse
+ *
+ * Returns 0 if success.
+ */
+static int sunxi_cpufreq_get_efuse(const struct sunxi_cpufreq_soc_data *soc_data,
+				   u32 *versions)
+{
+	struct nvmem_cell *speedbin_nvmem;
+	struct device_node *np;
+	struct device *cpu_dev;
+	u32 *speedbin;
+	size_t len;
+	int ret;
+
+	cpu_dev = get_cpu_device(0);
+	if (!cpu_dev)
+		return -ENODEV;
+
+	np = dev_pm_opp_of_get_opp_desc_node(cpu_dev);
+	if (!np)
+		return -ENOENT;
+
+	ret = of_device_is_compatible(np, "operating-points-v2-sunxi-cpu");
+	if (!ret) {
+		of_node_put(np);
+		return -ENOENT;
+	}
+
+	speedbin_nvmem = of_nvmem_cell_get(np, NULL);
+	of_node_put(np);
+	if (IS_ERR(speedbin_nvmem)) {
+		if (PTR_ERR(speedbin_nvmem) != -EPROBE_DEFER)
+			pr_err("Could not get nvmem cell: %ld\n",
+			PTR_ERR(speedbin_nvmem));
+		return PTR_ERR(speedbin_nvmem);
+	}
+
+	speedbin = nvmem_cell_read(speedbin_nvmem, &len);
+	nvmem_cell_put(speedbin_nvmem);
+	if (IS_ERR(speedbin))
+		return PTR_ERR(speedbin);
+
+	*versions = soc_data->efuse_xlate(soc_data, *speedbin);
+
+	kfree(speedbin);
+	return 0;
+};
+
+static const struct sunxi_cpufreq_soc_data sun50i_h6_data = {
+	.efuse_xlate = sun50i_efuse_xlate,
+	.nvmem_mask = 0x7,
+	.nvmem_shift = 5,
+};
+
+static const struct of_device_id sunxi_cpufreq_match_list[] = {
+	{ .compatible = "allwinner,sun50i-h6", .data = &sun50i_h6_data },
+	{}
+};
+
+static const struct of_device_id *sunxi_cpufreq_match_node(void)
+{
+	struct device_node *np;
+	const struct of_device_id *match;
+
+	np = of_find_node_by_path("/");
+	match = of_match_node(sunxi_cpufreq_match_list, np);
+	of_node_put(np);
+
+	return match;
+}
+
+static int sunxi_cpufreq_nvmem_probe(struct platform_device *pdev)
+{
+	const struct sunxi_cpufreq_soc_data *soc_data;
+	struct opp_table **opp_tables;
+	const struct of_device_id *match;
+	char name[MAX_NAME_LEN];
+	unsigned int cpu;
+	u32 speed = 0;
+	int ret;
+
+	opp_tables = kcalloc(num_possible_cpus(), sizeof(*opp_tables),
+			     GFP_KERNEL);
+	if (!opp_tables)
+		return -ENOMEM;
+
+	match = sunxi_cpufreq_match_node();
+	soc_data = match->data;
+	if (!soc_data)
+		return -EINVAL;
+
+	ret = sunxi_cpufreq_get_efuse(soc_data, &speed);
+	if (ret)
+		return ret;
+
+	snprintf(name, MAX_NAME_LEN, "speed%d", speed);
+
+	for_each_possible_cpu(cpu) {
+		struct device *cpu_dev = get_cpu_device(cpu);
+
+		if (NULL == cpu_dev) {
+			ret = -ENODEV;
+			goto free_opp;
+		}
+
+		opp_tables[cpu] = dev_pm_opp_set_prop_name(cpu_dev, name);
+		if (IS_ERR(opp_tables[cpu])) {
+			ret = PTR_ERR(opp_tables[cpu]);
+			pr_err("Failed to set prop name\n");
+			goto free_opp;
+		}
+	}
+
+	cpufreq_dt_pdev = platform_device_register_simple("cpufreq-dt", -1,
+							  NULL, 0);
+	if (!IS_ERR(cpufreq_dt_pdev)) {
+		platform_set_drvdata(pdev, opp_tables);
+		return 0;
+	}
+
+	ret = PTR_ERR(cpufreq_dt_pdev);
+	pr_err("Failed to register platform device\n");
+
+free_opp:
+	for_each_possible_cpu(cpu) {
+		if (IS_ERR_OR_NULL(opp_tables[cpu]))
+			break;
+		dev_pm_opp_put_prop_name(opp_tables[cpu]);
+	}
+	kfree(opp_tables);
+
+	return ret;
+}
+
+static int sunxi_cpufreq_nvmem_remove(struct platform_device *pdev)
+{
+	struct opp_table **opp_tables = platform_get_drvdata(pdev);
+	unsigned int cpu;
+
+	platform_device_unregister(cpufreq_dt_pdev);
+
+	for_each_possible_cpu(cpu)
+		dev_pm_opp_put_prop_name(opp_tables[cpu]);
+
+	kfree(opp_tables);
+
+	return 0;
+}
+
+static struct platform_driver sunxi_cpufreq_driver = {
+	.probe = sunxi_cpufreq_nvmem_probe,
+	.remove = sunxi_cpufreq_nvmem_remove,
+	.driver = {
+		.name = "sunxi-cpufreq-nvmem",
+	},
+};
+
+/*
+ * Since the driver depends on nvmem drivers, which may return EPROBE_DEFER,
+ * all the real activity is done in the probe, which may be defered as well.
+ * The init here is only registering the driver and the platform device.
+ */
+static int __init sunxi_cpufreq_init(void)
+{
+	const struct of_device_id *match;
+	int ret;
+
+	match = sunxi_cpufreq_match_node();
+	if (!match)
+		return -ENODEV;
+
+	ret = platform_driver_register(&sunxi_cpufreq_driver);
+	if (unlikely(ret < 0))
+		return ret;
+
+	sunxi_cpufreq_pdev = platform_device_register_simple(
+		"sunxi-cpufreq-nvmem", -1, NULL, 0);
+	ret = PTR_ERR_OR_ZERO(sunxi_cpufreq_pdev);
+	if (0 == ret)
+		return 0;
+
+	platform_driver_unregister(&sunxi_cpufreq_driver);
+	return ret;
+}
+module_init(sunxi_cpufreq_init);
+
+static void __exit sunxi_cpufreq_exit(void)
+{
+	platform_device_unregister(sunxi_cpufreq_pdev);
+	platform_driver_unregister(&sunxi_cpufreq_driver);
+}
+module_exit(sunxi_cpufreq_exit);
+
+MODULE_DESCRIPTION("Sunxi cpufreq driver");
+MODULE_LICENSE("GPL v2");