052c6f1914
The RCU locking isn't well suited for the OPP core. The RCU locking fits better for reader heavy stuff, while the OPP core have at max one or two readers only at a time. Over that, it was getting very confusing the way RCU locking was used with the OPP core. The individual OPPs are mostly well handled, i.e. for an update a new structure was created and then that replaced the older one. But the OPP tables were updated directly all the time from various parts of the core. Though they were mostly used from within RCU locked region, they didn't had much to do with RCU and were governed by the mutex instead. And that mixed with the 'opp_table_lock' has made the core even more confusing. Now that we are already managing the OPPs and the OPP tables with kernel reference infrastructure, we can get rid of RCU locking completely and simplify the code a lot. Remove all RCU references from code and comments. Acquire opp_table->lock while parsing the list of OPPs though. Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Reviewed-by: Stephen Boyd <sboyd@codeaurora.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
223 lines
6.9 KiB
C
223 lines
6.9 KiB
C
/*
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* Generic OPP Interface
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*
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* Copyright (C) 2009-2010 Texas Instruments Incorporated.
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* Nishanth Menon
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* Romit Dasgupta
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* Kevin Hilman
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#ifndef __DRIVER_OPP_H__
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#define __DRIVER_OPP_H__
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#include <linux/device.h>
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#include <linux/kernel.h>
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#include <linux/kref.h>
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#include <linux/list.h>
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#include <linux/limits.h>
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#include <linux/pm_opp.h>
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#include <linux/notifier.h>
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struct clk;
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struct regulator;
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/* Lock to allow exclusive modification to the device and opp lists */
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extern struct mutex opp_table_lock;
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extern struct list_head opp_tables;
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/*
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* Internal data structure organization with the OPP layer library is as
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* follows:
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* opp_tables (root)
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* |- device 1 (represents voltage domain 1)
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* | |- opp 1 (availability, freq, voltage)
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* | |- opp 2 ..
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* ... ...
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* | `- opp n ..
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* |- device 2 (represents the next voltage domain)
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* ...
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* `- device m (represents mth voltage domain)
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* device 1, 2.. are represented by opp_table structure while each opp
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* is represented by the opp structure.
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*/
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/**
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* struct dev_pm_opp - Generic OPP description structure
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* @node: opp table node. The nodes are maintained throughout the lifetime
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* of boot. It is expected only an optimal set of OPPs are
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* added to the library by the SoC framework.
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* IMPORTANT: the opp nodes should be maintained in increasing
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* order.
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* @kref: for reference count of the OPP.
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* @available: true/false - marks if this OPP as available or not
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* @dynamic: not-created from static DT entries.
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* @turbo: true if turbo (boost) OPP
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* @suspend: true if suspend OPP
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* @rate: Frequency in hertz
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* @supplies: Power supplies voltage/current values
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* @clock_latency_ns: Latency (in nanoseconds) of switching to this OPP's
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* frequency from any other OPP's frequency.
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* @opp_table: points back to the opp_table struct this opp belongs to
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* @np: OPP's device node.
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* @dentry: debugfs dentry pointer (per opp)
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*
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* This structure stores the OPP information for a given device.
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*/
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struct dev_pm_opp {
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struct list_head node;
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struct kref kref;
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bool available;
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bool dynamic;
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bool turbo;
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bool suspend;
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unsigned long rate;
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struct dev_pm_opp_supply *supplies;
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unsigned long clock_latency_ns;
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struct opp_table *opp_table;
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struct device_node *np;
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#ifdef CONFIG_DEBUG_FS
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struct dentry *dentry;
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#endif
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};
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/**
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* struct opp_device - devices managed by 'struct opp_table'
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* @node: list node
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* @dev: device to which the struct object belongs
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* @dentry: debugfs dentry pointer (per device)
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*
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* This is an internal data structure maintaining the devices that are managed
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* by 'struct opp_table'.
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*/
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struct opp_device {
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struct list_head node;
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const struct device *dev;
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#ifdef CONFIG_DEBUG_FS
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struct dentry *dentry;
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#endif
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};
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enum opp_table_access {
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OPP_TABLE_ACCESS_UNKNOWN = 0,
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OPP_TABLE_ACCESS_EXCLUSIVE = 1,
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OPP_TABLE_ACCESS_SHARED = 2,
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};
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/**
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* struct opp_table - Device opp structure
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* @node: table node - contains the devices with OPPs that
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* have been registered. Nodes once added are not modified in this
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* table.
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* @head: notifier head to notify the OPP availability changes.
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* @dev_list: list of devices that share these OPPs
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* @opp_list: table of opps
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* @kref: for reference count of the table.
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* @lock: mutex protecting the opp_list.
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* @np: struct device_node pointer for opp's DT node.
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* @clock_latency_ns_max: Max clock latency in nanoseconds.
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* @shared_opp: OPP is shared between multiple devices.
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* @suspend_opp: Pointer to OPP to be used during device suspend.
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* @supported_hw: Array of version number to support.
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* @supported_hw_count: Number of elements in supported_hw array.
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* @prop_name: A name to postfix to many DT properties, while parsing them.
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* @clk: Device's clock handle
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* @regulators: Supply regulators
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* @regulator_count: Number of power supply regulators
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* @set_opp: Platform specific set_opp callback
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* @set_opp_data: Data to be passed to set_opp callback
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* @dentry: debugfs dentry pointer of the real device directory (not links).
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* @dentry_name: Name of the real dentry.
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*
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* @voltage_tolerance_v1: In percentage, for v1 bindings only.
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*
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* This is an internal data structure maintaining the link to opps attached to
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* a device. This structure is not meant to be shared to users as it is
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* meant for book keeping and private to OPP library.
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*/
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struct opp_table {
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struct list_head node;
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struct blocking_notifier_head head;
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struct list_head dev_list;
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struct list_head opp_list;
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struct kref kref;
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struct mutex lock;
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struct device_node *np;
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unsigned long clock_latency_ns_max;
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/* For backward compatibility with v1 bindings */
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unsigned int voltage_tolerance_v1;
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enum opp_table_access shared_opp;
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struct dev_pm_opp *suspend_opp;
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unsigned int *supported_hw;
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unsigned int supported_hw_count;
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const char *prop_name;
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struct clk *clk;
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struct regulator **regulators;
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unsigned int regulator_count;
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int (*set_opp)(struct dev_pm_set_opp_data *data);
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struct dev_pm_set_opp_data *set_opp_data;
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#ifdef CONFIG_DEBUG_FS
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struct dentry *dentry;
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char dentry_name[NAME_MAX];
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#endif
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};
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/* Routines internal to opp core */
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void _get_opp_table_kref(struct opp_table *opp_table);
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struct opp_table *_find_opp_table(struct device *dev);
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struct opp_device *_add_opp_dev(const struct device *dev, struct opp_table *opp_table);
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void _dev_pm_opp_remove_table(struct opp_table *opp_table, struct device *dev, bool remove_all);
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void _dev_pm_opp_find_and_remove_table(struct device *dev, bool remove_all);
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struct dev_pm_opp *_opp_allocate(struct opp_table *opp_table);
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void _opp_free(struct dev_pm_opp *opp);
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int _opp_add(struct device *dev, struct dev_pm_opp *new_opp, struct opp_table *opp_table);
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int _opp_add_v1(struct opp_table *opp_table, struct device *dev, unsigned long freq, long u_volt, bool dynamic);
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void _dev_pm_opp_cpumask_remove_table(const struct cpumask *cpumask, bool of);
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struct opp_table *_add_opp_table(struct device *dev);
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#ifdef CONFIG_OF
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void _of_init_opp_table(struct opp_table *opp_table, struct device *dev);
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#else
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static inline void _of_init_opp_table(struct opp_table *opp_table, struct device *dev) {}
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#endif
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#ifdef CONFIG_DEBUG_FS
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void opp_debug_remove_one(struct dev_pm_opp *opp);
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int opp_debug_create_one(struct dev_pm_opp *opp, struct opp_table *opp_table);
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int opp_debug_register(struct opp_device *opp_dev, struct opp_table *opp_table);
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void opp_debug_unregister(struct opp_device *opp_dev, struct opp_table *opp_table);
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#else
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static inline void opp_debug_remove_one(struct dev_pm_opp *opp) {}
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static inline int opp_debug_create_one(struct dev_pm_opp *opp,
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struct opp_table *opp_table)
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{ return 0; }
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static inline int opp_debug_register(struct opp_device *opp_dev,
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struct opp_table *opp_table)
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{ return 0; }
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static inline void opp_debug_unregister(struct opp_device *opp_dev,
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struct opp_table *opp_table)
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{ }
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#endif /* DEBUG_FS */
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#endif /* __DRIVER_OPP_H__ */
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