[v8,2/3] ACPI: platform-profile: Add platform profile support

Commit Message

Mark Pearson Dec. 30, 2020, 12:18 a.m. UTC

This is the initial implementation of the platform-profile feature.
It provides the details discussed and outlined in the
sysfs-platform_profile document.

Many modern systems have the ability to modify the operating profile to
control aspects like fan speed, temperature and power levels. This
module provides a common sysfs interface that platform modules can register
against to control their individual profile options.

Signed-off-by: Mark Pearson <[e-mail]>
---
Changes in v2:
 Address (hopefully) all recommendations from review including:
 - reorder includes list alphabetically
 - make globals statics and use const as required
 - change profile name scanning to use full string
 - clean up profile name lists to remove unwanted additions
 - use sysfs_emit and sysfs_emit_at appropriately (much nicer!)
 - improve error handling. Return errors to user in all cases and use
   better error codes where appropriate (ENOOPSUPP)
 - clean up sysfs output for better readability
 - formatting fixes where needed
 - improve structure and enum names to be clearer
 - remove cur_profile field from structure. It is now local to the
   actual platform driver file (patch 3 in series)
 - improve checking so if future profile options are added profile_names
   will be updated as well.
 - move CONFIG option next to ACPI_THERMAL as it seemed slightly related
 - removed MAINTAINERS update as not appropriate (note warning message
   is seen when running checkpatch)

Changes in v3:
 - Add missed platform_profile.h file

Changes in v4:
 - Clean up duplicate entry in Kconfig file
 - Add linux/bits.h to include list
 - Remove unnecessary items from include list
 - Make cur_profile const
 - Clean up comments
 - formatting clean-ups
 - add checking of profile return value to show function
 - add checking to store to see if it's a supported profile
 - revert ENOTSUPP change in store function
 - improved error checking in profile registration
 - improved profile naming (now platform_profile_*)

Changes in v5:
 - correct 'balance' to 'balanced' to be consistent with documentation
 - add WARN_ON when checking profile index in show function
 - switch mutex_lock_interruptible back to mutex_lock where appropriate
 - add 'platform_profile_last' as final entry in profile entry. Update
   implementation to use this appropriately
 - Use BITS_TO_LONG and appropriate access functions for choices field
 - Correct error handling as recommended
 - Sanity check profile fields on registration
 - Remove unnecessary init and exit functions

Changed in v6:
 - Change default build option to 'm' and clean in formating in Kconfig
 - Change enums to be capitalised as requested
 - Rename unregister function to remove

Changes in v7
 - version bump along with rest of patch series

Changes in v8:
 - correct checking for empty choices bitmap in register function

 drivers/acpi/Kconfig             |  17 +++
 drivers/acpi/Makefile            |   1 +
 drivers/acpi/platform_profile.c  | 181 +++++++++++++++++++++++++++++++
 include/linux/platform_profile.h |  39 +++++++
 4 files changed, 238 insertions(+)
 create mode 100644 drivers/acpi/platform_profile.c
 create mode 100644 include/linux/platform_profile.h

Comments

Rafael J. Wysocki Dec. 30, 2020, 5:40 p.m. UTC | #1

On Wed, Dec 30, 2020 at 1:24 AM Mark Pearson <[e-mail]> wrote:
>
> This is the initial implementation of the platform-profile feature.
> It provides the details discussed and outlined in the
> sysfs-platform_profile document.
>
> Many modern systems have the ability to modify the operating profile to
> control aspects like fan speed, temperature and power levels. This
> module provides a common sysfs interface that platform modules can register
> against to control their individual profile options.
>
> Signed-off-by: Mark Pearson <[e-mail]>
> ---
> Changes in v2:
>  Address (hopefully) all recommendations from review including:
>  - reorder includes list alphabetically
>  - make globals statics and use const as required
>  - change profile name scanning to use full string
>  - clean up profile name lists to remove unwanted additions
>  - use sysfs_emit and sysfs_emit_at appropriately (much nicer!)
>  - improve error handling. Return errors to user in all cases and use
>    better error codes where appropriate (ENOOPSUPP)
>  - clean up sysfs output for better readability
>  - formatting fixes where needed
>  - improve structure and enum names to be clearer
>  - remove cur_profile field from structure. It is now local to the
>    actual platform driver file (patch 3 in series)
>  - improve checking so if future profile options are added profile_names
>    will be updated as well.
>  - move CONFIG option next to ACPI_THERMAL as it seemed slightly related
>  - removed MAINTAINERS update as not appropriate (note warning message
>    is seen when running checkpatch)
>
> Changes in v3:
>  - Add missed platform_profile.h file
>
> Changes in v4:
>  - Clean up duplicate entry in Kconfig file
>  - Add linux/bits.h to include list
>  - Remove unnecessary items from include list
>  - Make cur_profile const
>  - Clean up comments
>  - formatting clean-ups
>  - add checking of profile return value to show function
>  - add checking to store to see if it's a supported profile
>  - revert ENOTSUPP change in store function
>  - improved error checking in profile registration
>  - improved profile naming (now platform_profile_*)
>
> Changes in v5:
>  - correct 'balance' to 'balanced' to be consistent with documentation
>  - add WARN_ON when checking profile index in show function
>  - switch mutex_lock_interruptible back to mutex_lock where appropriate
>  - add 'platform_profile_last' as final entry in profile entry. Update
>    implementation to use this appropriately
>  - Use BITS_TO_LONG and appropriate access functions for choices field
>  - Correct error handling as recommended
>  - Sanity check profile fields on registration
>  - Remove unnecessary init and exit functions
>
> Changed in v6:
>  - Change default build option to 'm' and clean in formating in Kconfig
>  - Change enums to be capitalised as requested
>  - Rename unregister function to remove
>
> Changes in v7
>  - version bump along with rest of patch series
>
> Changes in v8:
>  - correct checking for empty choices bitmap in register function

Applied with the Hans' R-by and I replaced PLATFORM_PROFILE_LOW and
PLATFORM_PROFILE_PERFORM with PLATFORM_PROFILE_LOW_POWER and
PLATFORM_PROFILE_PERFORMANCE, respectively.

Thanks!

>  drivers/acpi/Kconfig             |  17 +++
>  drivers/acpi/Makefile            |   1 +
>  drivers/acpi/platform_profile.c  | 181 +++++++++++++++++++++++++++++++
>  include/linux/platform_profile.h |  39 +++++++
>  4 files changed, 238 insertions(+)
>  create mode 100644 drivers/acpi/platform_profile.c
>  create mode 100644 include/linux/platform_profile.h
>
> diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig
> index edf1558c1105..5ddff93e38c2 100644
> --- a/drivers/acpi/Kconfig
> +++ b/drivers/acpi/Kconfig
> @@ -326,6 +326,23 @@ config ACPI_THERMAL
>           To compile this driver as a module, choose M here:
>           the module will be called thermal.
>
> +config ACPI_PLATFORM_PROFILE
> +       tristate "ACPI Platform Profile Driver"
> +       default m
> +       help
> +         This driver adds support for platform-profiles on platforms that
> +         support it.
> +
> +         Platform-profiles can be used to control the platform behaviour. For
> +         example whether to operate in a lower power mode, in a higher
> +         power performance mode or between the two.
> +
> +         This driver provides the sysfs interface and is used as the registration
> +         point for platform specific drivers.
> +
> +         Which profiles are supported is determined on a per-platform basis and
> +         should be obtained from the platform specific driver.
> +
>  config ACPI_CUSTOM_DSDT_FILE
>         string "Custom DSDT Table file to include"
>         default ""
> diff --git a/drivers/acpi/Makefile b/drivers/acpi/Makefile
> index 44e412506317..c64a8af106c0 100644
> --- a/drivers/acpi/Makefile
> +++ b/drivers/acpi/Makefile
> @@ -78,6 +78,7 @@ obj-$(CONFIG_ACPI_PCI_SLOT)   += pci_slot.o
>  obj-$(CONFIG_ACPI_PROCESSOR)   += processor.o
>  obj-$(CONFIG_ACPI)             += container.o
>  obj-$(CONFIG_ACPI_THERMAL)     += thermal.o
> +obj-$(CONFIG_ACPI_PLATFORM_PROFILE)    += platform_profile.o
>  obj-$(CONFIG_ACPI_NFIT)                += nfit/
>  obj-$(CONFIG_ACPI_NUMA)                += numa/
>  obj-$(CONFIG_ACPI)             += acpi_memhotplug.o
> diff --git a/drivers/acpi/platform_profile.c b/drivers/acpi/platform_profile.c
> new file mode 100644
> index 000000000000..f65aa8cd2185
> --- /dev/null
> +++ b/drivers/acpi/platform_profile.c
> @@ -0,0 +1,181 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +
> +/* Platform profile sysfs interface */
> +
> +#include <linux/acpi.h>
> +#include <linux/bits.h>
> +#include <linux/init.h>
> +#include <linux/mutex.h>
> +#include <linux/platform_profile.h>
> +#include <linux/sysfs.h>
> +
> +static const struct platform_profile_handler *cur_profile;
> +static DEFINE_MUTEX(profile_lock);
> +
> +static const char * const profile_names[] = {
> +       [PLATFORM_PROFILE_LOW] = "low-power",
> +       [PLATFORM_PROFILE_COOL] = "cool",
> +       [PLATFORM_PROFILE_QUIET] = "quiet",
> +       [PLATFORM_PROFILE_BALANCED] = "balanced",
> +       [PLATFORM_PROFILE_PERFORM] = "performance",
> +};
> +static_assert(ARRAY_SIZE(profile_names) == PLATFORM_PROFILE_LAST);
> +
> +static ssize_t platform_profile_choices_show(struct device *dev,
> +                                       struct device_attribute *attr,
> +                                       char *buf)
> +{
> +       int len = 0;
> +       int err, i;
> +
> +       err = mutex_lock_interruptible(&profile_lock);
> +       if (err)
> +               return err;
> +
> +       if (!cur_profile) {
> +               mutex_unlock(&profile_lock);
> +               return -ENODEV;
> +       }
> +
> +       for_each_set_bit(i, cur_profile->choices, PLATFORM_PROFILE_LAST) {
> +               if (len == 0)
> +                       len += sysfs_emit_at(buf, len, "%s", profile_names[i]);
> +               else
> +                       len += sysfs_emit_at(buf, len, " %s", profile_names[i]);
> +       }
> +       len += sysfs_emit_at(buf, len, "\n");
> +       mutex_unlock(&profile_lock);
> +       return len;
> +}
> +
> +static ssize_t platform_profile_show(struct device *dev,
> +                                       struct device_attribute *attr,
> +                                       char *buf)
> +{
> +       enum platform_profile_option profile = PLATFORM_PROFILE_BALANCED;
> +       int err;
> +
> +       err = mutex_lock_interruptible(&profile_lock);
> +       if (err)
> +               return err;
> +
> +       if (!cur_profile) {
> +               mutex_unlock(&profile_lock);
> +               return -ENODEV;
> +       }
> +
> +       err = cur_profile->profile_get(&profile);
> +       mutex_unlock(&profile_lock);
> +       if (err)
> +               return err;
> +
> +       /* Check that profile is valid index */
> +       if (WARN_ON((profile < 0) || (profile >= ARRAY_SIZE(profile_names))))
> +               return -EIO;
> +
> +       return sysfs_emit(buf, "%s\n", profile_names[profile]);
> +}
> +
> +static ssize_t platform_profile_store(struct device *dev,
> +                           struct device_attribute *attr,
> +                           const char *buf, size_t count)
> +{
> +       int err, i;
> +
> +       err = mutex_lock_interruptible(&profile_lock);
> +       if (err)
> +               return err;
> +
> +       if (!cur_profile) {
> +               mutex_unlock(&profile_lock);
> +               return -ENODEV;
> +       }
> +
> +       /* Scan for a matching profile */
> +       i = sysfs_match_string(profile_names, buf);
> +       if (i < 0) {
> +               mutex_unlock(&profile_lock);
> +               return -EINVAL;
> +       }
> +
> +       /* Check that platform supports this profile choice */
> +       if (!test_bit(i, cur_profile->choices)) {
> +               mutex_unlock(&profile_lock);
> +               return -EOPNOTSUPP;
> +       }
> +
> +       err = cur_profile->profile_set(i);
> +       mutex_unlock(&profile_lock);
> +       if (err)
> +               return err;
> +       return count;
> +}
> +
> +static DEVICE_ATTR_RO(platform_profile_choices);
> +static DEVICE_ATTR_RW(platform_profile);
> +
> +static struct attribute *platform_profile_attrs[] = {
> +       &dev_attr_platform_profile_choices.attr,
> +       &dev_attr_platform_profile.attr,
> +       NULL
> +};
> +
> +static const struct attribute_group platform_profile_group = {
> +       .attrs = platform_profile_attrs
> +};
> +
> +void platform_profile_notify(void)
> +{
> +       if (!cur_profile)
> +               return;
> +       sysfs_notify(acpi_kobj, NULL, "platform_profile");
> +}
> +EXPORT_SYMBOL_GPL(platform_profile_notify);
> +
> +int platform_profile_register(const struct platform_profile_handler *pprof)
> +{
> +       int err;
> +
> +       mutex_lock(&profile_lock);
> +       /* We can only have one active profile */
> +       if (cur_profile) {
> +               mutex_unlock(&profile_lock);
> +               return -EEXIST;
> +       }
> +
> +       /* Sanity check the profile handler field are set */
> +       if (!pprof || bitmap_empty(pprof->choices, PLATFORM_PROFILE_LAST) ||
> +               !pprof->profile_set || !pprof->profile_get) {
> +               mutex_unlock(&profile_lock);
> +               return -EINVAL;
> +       }
> +
> +       err = sysfs_create_group(acpi_kobj, &platform_profile_group);
> +       if (err) {
> +               mutex_unlock(&profile_lock);
> +               return err;
> +       }
> +
> +       cur_profile = pprof;
> +       mutex_unlock(&profile_lock);
> +       return 0;
> +}
> +EXPORT_SYMBOL_GPL(platform_profile_register);
> +
> +int platform_profile_remove(void)
> +{
> +       mutex_lock(&profile_lock);
> +       if (!cur_profile) {
> +               mutex_unlock(&profile_lock);
> +               return -ENODEV;
> +       }
> +
> +       sysfs_remove_group(acpi_kobj, &platform_profile_group);
> +       cur_profile = NULL;
> +       mutex_unlock(&profile_lock);
> +       return 0;
> +}
> +EXPORT_SYMBOL_GPL(platform_profile_remove);
> +
> +MODULE_AUTHOR("Mark Pearson <[e-mail]>");
> +MODULE_LICENSE("GPL");
> diff --git a/include/linux/platform_profile.h b/include/linux/platform_profile.h
> new file mode 100644
> index 000000000000..9a1e2abd7602
> --- /dev/null
> +++ b/include/linux/platform_profile.h
> @@ -0,0 +1,39 @@
> +/* SPDX-License-Identifier: GPL-2.0-or-later */
> +/*
> + * Platform profile sysfs interface
> + *
> + * See Documentation/ABI/testing/sysfs-platform_profile.rst for more
> + * information.
> + */
> +
> +#ifndef _PLATFORM_PROFILE_H_
> +#define _PLATFORM_PROFILE_H_
> +
> +#include <linux/bitops.h>
> +
> +/*
> + * If more options are added please update profile_names
> + * array in platform-profile.c and sysfs-platform-profile.rst
> + * documentation.
> + */
> +
> +enum platform_profile_option {
> +       PLATFORM_PROFILE_LOW,
> +       PLATFORM_PROFILE_COOL,
> +       PLATFORM_PROFILE_QUIET,
> +       PLATFORM_PROFILE_BALANCED,
> +       PLATFORM_PROFILE_PERFORM,
> +       PLATFORM_PROFILE_LAST, /*must always be last */
> +};
> +
> +struct platform_profile_handler {
> +       unsigned long choices[BITS_TO_LONGS(PLATFORM_PROFILE_LAST)];
> +       int (*profile_get)(enum platform_profile_option *profile);
> +       int (*profile_set)(enum platform_profile_option profile);
> +};
> +
> +int platform_profile_register(const struct platform_profile_handler *pprof);
> +int platform_profile_remove(void);
> +void platform_profile_notify(void);
> +
> +#endif  /*_PLATFORM_PROFILE_H_*/
> --
> 2.28.0
>

Patch

diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig
index edf1558c1105..5ddff93e38c2 100644
--- a/drivers/acpi/Kconfig
+++ b/drivers/acpi/Kconfig
@@ -326,6 +326,23 @@  config ACPI_THERMAL
 	  To compile this driver as a module, choose M here:
 	  the module will be called thermal.
 
+config ACPI_PLATFORM_PROFILE
+	tristate "ACPI Platform Profile Driver"
+	default m
+	help
+	  This driver adds support for platform-profiles on platforms that
+	  support it.
+
+	  Platform-profiles can be used to control the platform behaviour. For
+	  example whether to operate in a lower power mode, in a higher
+	  power performance mode or between the two.
+
+	  This driver provides the sysfs interface and is used as the registration
+	  point for platform specific drivers.
+
+	  Which profiles are supported is determined on a per-platform basis and
+	  should be obtained from the platform specific driver.
+
 config ACPI_CUSTOM_DSDT_FILE
 	string "Custom DSDT Table file to include"
 	default ""
diff --git a/drivers/acpi/Makefile b/drivers/acpi/Makefile
index 44e412506317..c64a8af106c0 100644
--- a/drivers/acpi/Makefile
+++ b/drivers/acpi/Makefile
@@ -78,6 +78,7 @@  obj-$(CONFIG_ACPI_PCI_SLOT)	+= pci_slot.o
 obj-$(CONFIG_ACPI_PROCESSOR)	+= processor.o
 obj-$(CONFIG_ACPI)		+= container.o
 obj-$(CONFIG_ACPI_THERMAL)	+= thermal.o
+obj-$(CONFIG_ACPI_PLATFORM_PROFILE) 	+= platform_profile.o
 obj-$(CONFIG_ACPI_NFIT)		+= nfit/
 obj-$(CONFIG_ACPI_NUMA)		+= numa/
 obj-$(CONFIG_ACPI)		+= acpi_memhotplug.o
diff --git a/drivers/acpi/platform_profile.c b/drivers/acpi/platform_profile.c
new file mode 100644
index 000000000000..f65aa8cd2185
--- /dev/null
+++ b/drivers/acpi/platform_profile.c
@@ -0,0 +1,181 @@ 
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+/* Platform profile sysfs interface */
+
+#include <linux/acpi.h>
+#include <linux/bits.h>
+#include <linux/init.h>
+#include <linux/mutex.h>
+#include <linux/platform_profile.h>
+#include <linux/sysfs.h>
+
+static const struct platform_profile_handler *cur_profile;
+static DEFINE_MUTEX(profile_lock);
+
+static const char * const profile_names[] = {
+	[PLATFORM_PROFILE_LOW] = "low-power",
+	[PLATFORM_PROFILE_COOL] = "cool",
+	[PLATFORM_PROFILE_QUIET] = "quiet",
+	[PLATFORM_PROFILE_BALANCED] = "balanced",
+	[PLATFORM_PROFILE_PERFORM] = "performance",
+};
+static_assert(ARRAY_SIZE(profile_names) == PLATFORM_PROFILE_LAST);
+
+static ssize_t platform_profile_choices_show(struct device *dev,
+					struct device_attribute *attr,
+					char *buf)
+{
+	int len = 0;
+	int err, i;
+
+	err = mutex_lock_interruptible(&profile_lock);
+	if (err)
+		return err;
+
+	if (!cur_profile) {
+		mutex_unlock(&profile_lock);
+		return -ENODEV;
+	}
+
+	for_each_set_bit(i, cur_profile->choices, PLATFORM_PROFILE_LAST) {
+		if (len == 0)
+			len += sysfs_emit_at(buf, len, "%s", profile_names[i]);
+		else
+			len += sysfs_emit_at(buf, len, " %s", profile_names[i]);
+	}
+	len += sysfs_emit_at(buf, len, "\n");
+	mutex_unlock(&profile_lock);
+	return len;
+}
+
+static ssize_t platform_profile_show(struct device *dev,
+					struct device_attribute *attr,
+					char *buf)
+{
+	enum platform_profile_option profile = PLATFORM_PROFILE_BALANCED;
+	int err;
+
+	err = mutex_lock_interruptible(&profile_lock);
+	if (err)
+		return err;
+
+	if (!cur_profile) {
+		mutex_unlock(&profile_lock);
+		return -ENODEV;
+	}
+
+	err = cur_profile->profile_get(&profile);
+	mutex_unlock(&profile_lock);
+	if (err)
+		return err;
+
+	/* Check that profile is valid index */
+	if (WARN_ON((profile < 0) || (profile >= ARRAY_SIZE(profile_names))))
+		return -EIO;
+
+	return sysfs_emit(buf, "%s\n", profile_names[profile]);
+}
+
+static ssize_t platform_profile_store(struct device *dev,
+			    struct device_attribute *attr,
+			    const char *buf, size_t count)
+{
+	int err, i;
+
+	err = mutex_lock_interruptible(&profile_lock);
+	if (err)
+		return err;
+
+	if (!cur_profile) {
+		mutex_unlock(&profile_lock);
+		return -ENODEV;
+	}
+
+	/* Scan for a matching profile */
+	i = sysfs_match_string(profile_names, buf);
+	if (i < 0) {
+		mutex_unlock(&profile_lock);
+		return -EINVAL;
+	}
+
+	/* Check that platform supports this profile choice */
+	if (!test_bit(i, cur_profile->choices)) {
+		mutex_unlock(&profile_lock);
+		return -EOPNOTSUPP;
+	}
+
+	err = cur_profile->profile_set(i);
+	mutex_unlock(&profile_lock);
+	if (err)
+		return err;
+	return count;
+}
+
+static DEVICE_ATTR_RO(platform_profile_choices);
+static DEVICE_ATTR_RW(platform_profile);
+
+static struct attribute *platform_profile_attrs[] = {
+	&dev_attr_platform_profile_choices.attr,
+	&dev_attr_platform_profile.attr,
+	NULL
+};
+
+static const struct attribute_group platform_profile_group = {
+	.attrs = platform_profile_attrs
+};
+
+void platform_profile_notify(void)
+{
+	if (!cur_profile)
+		return;
+	sysfs_notify(acpi_kobj, NULL, "platform_profile");
+}
+EXPORT_SYMBOL_GPL(platform_profile_notify);
+
+int platform_profile_register(const struct platform_profile_handler *pprof)
+{
+	int err;
+
+	mutex_lock(&profile_lock);
+	/* We can only have one active profile */
+	if (cur_profile) {
+		mutex_unlock(&profile_lock);
+		return -EEXIST;
+	}
+
+	/* Sanity check the profile handler field are set */
+	if (!pprof || bitmap_empty(pprof->choices, PLATFORM_PROFILE_LAST) ||
+		!pprof->profile_set || !pprof->profile_get) {
+		mutex_unlock(&profile_lock);
+		return -EINVAL;
+	}
+
+	err = sysfs_create_group(acpi_kobj, &platform_profile_group);
+	if (err) {
+		mutex_unlock(&profile_lock);
+		return err;
+	}
+
+	cur_profile = pprof;
+	mutex_unlock(&profile_lock);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(platform_profile_register);
+
+int platform_profile_remove(void)
+{
+	mutex_lock(&profile_lock);
+	if (!cur_profile) {
+		mutex_unlock(&profile_lock);
+		return -ENODEV;
+	}
+
+	sysfs_remove_group(acpi_kobj, &platform_profile_group);
+	cur_profile = NULL;
+	mutex_unlock(&profile_lock);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(platform_profile_remove);
+
+MODULE_AUTHOR("Mark Pearson <[e-mail]>");
+MODULE_LICENSE("GPL");
diff --git a/include/linux/platform_profile.h b/include/linux/platform_profile.h
new file mode 100644
index 000000000000..9a1e2abd7602
--- /dev/null
+++ b/include/linux/platform_profile.h
@@ -0,0 +1,39 @@ 
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Platform profile sysfs interface
+ *
+ * See Documentation/ABI/testing/sysfs-platform_profile.rst for more
+ * information.
+ */
+
+#ifndef _PLATFORM_PROFILE_H_
+#define _PLATFORM_PROFILE_H_
+
+#include <linux/bitops.h>
+
+/*
+ * If more options are added please update profile_names
+ * array in platform-profile.c and sysfs-platform-profile.rst
+ * documentation.
+ */
+
+enum platform_profile_option {
+	PLATFORM_PROFILE_LOW,
+	PLATFORM_PROFILE_COOL,
+	PLATFORM_PROFILE_QUIET,
+	PLATFORM_PROFILE_BALANCED,
+	PLATFORM_PROFILE_PERFORM,
+	PLATFORM_PROFILE_LAST, /*must always be last */
+};
+
+struct platform_profile_handler {
+	unsigned long choices[BITS_TO_LONGS(PLATFORM_PROFILE_LAST)];
+	int (*profile_get)(enum platform_profile_option *profile);
+	int (*profile_set)(enum platform_profile_option profile);
+};
+
+int platform_profile_register(const struct platform_profile_handler *pprof);
+int platform_profile_remove(void);
+void platform_profile_notify(void);
+
+#endif  /*_PLATFORM_PROFILE_H_*/