2 * Generic OPP Interface
4 * Copyright (C) 2009-2010 Texas Instruments Incorporated.
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License version 2 as
11 * published by the Free Software Foundation.
14 #ifndef __DRIVER_OPP_H__
15 #define __DRIVER_OPP_H__
17 #include <linux/device.h>
18 #include <linux/kernel.h>
19 #include <linux/list.h>
20 #include <linux/limits.h>
21 #include <linux/pm_opp.h>
22 #include <linux/rculist.h>
23 #include <linux/rcupdate.h>
27 /* Lock to allow exclusive modification to the device and opp lists */
28 extern struct mutex dev_opp_list_lock;
31 * Internal data structure organization with the OPP layer library is as
34 * |- device 1 (represents voltage domain 1)
35 * | |- opp 1 (availability, freq, voltage)
39 * |- device 2 (represents the next voltage domain)
41 * `- device m (represents mth voltage domain)
42 * device 1, 2.. are represented by dev_opp structure while each opp
43 * is represented by the opp structure.
47 * struct dev_pm_opp - Generic OPP description structure
48 * @node: opp list node. The nodes are maintained throughout the lifetime
49 * of boot. It is expected only an optimal set of OPPs are
50 * added to the library by the SoC framework.
51 * RCU usage: opp list is traversed with RCU locks. node
52 * modification is possible realtime, hence the modifications
53 * are protected by the dev_opp_list_lock for integrity.
54 * IMPORTANT: the opp nodes should be maintained in increasing
56 * @available: true/false - marks if this OPP as available or not
57 * @dynamic: not-created from static DT entries.
58 * @turbo: true if turbo (boost) OPP
59 * @suspend: true if suspend OPP
60 * @rate: Frequency in hertz
61 * @u_volt: Target voltage in microvolts corresponding to this OPP
62 * @u_volt_min: Minimum voltage in microvolts corresponding to this OPP
63 * @u_volt_max: Maximum voltage in microvolts corresponding to this OPP
64 * @u_amp: Maximum current drawn by the device in microamperes
65 * @clock_latency_ns: Latency (in nanoseconds) of switching to this OPP's
66 * frequency from any other OPP's frequency.
67 * @dev_opp: points back to the device_opp struct this opp belongs to
68 * @rcu_head: RCU callback head used for deferred freeing
69 * @np: OPP's device node.
70 * @dentry: debugfs dentry pointer (per opp)
72 * This structure stores the OPP information for a given device.
75 struct list_head node;
84 unsigned long u_volt_min;
85 unsigned long u_volt_max;
87 unsigned long clock_latency_ns;
89 struct device_opp *dev_opp;
90 struct rcu_head rcu_head;
92 struct device_node *np;
94 #ifdef CONFIG_DEBUG_FS
95 struct dentry *dentry;
100 * struct device_list_opp - devices managed by 'struct device_opp'
102 * @dev: device to which the struct object belongs
103 * @rcu_head: RCU callback head used for deferred freeing
104 * @dentry: debugfs dentry pointer (per device)
106 * This is an internal data structure maintaining the list of devices that are
107 * managed by 'struct device_opp'.
109 struct device_list_opp {
110 struct list_head node;
111 const struct device *dev;
112 struct rcu_head rcu_head;
114 #ifdef CONFIG_DEBUG_FS
115 struct dentry *dentry;
120 * struct device_opp - Device opp structure
121 * @node: list node - contains the devices with OPPs that
122 * have been registered. Nodes once added are not modified in this
124 * RCU usage: nodes are not modified in the list of device_opp,
125 * however addition is possible and is secured by dev_opp_list_lock
126 * @srcu_head: notifier head to notify the OPP availability changes.
127 * @rcu_head: RCU callback head used for deferred freeing
128 * @dev_list: list of devices that share these OPPs
129 * @opp_list: list of opps
130 * @np: struct device_node pointer for opp's DT node.
131 * @clock_latency_ns_max: Max clock latency in nanoseconds.
132 * @shared_opp: OPP is shared between multiple devices.
133 * @suspend_opp: Pointer to OPP to be used during device suspend.
134 * @supported_hw: Array of version number to support.
135 * @supported_hw_count: Number of elements in supported_hw array.
136 * @prop_name: A name to postfix to many DT properties, while parsing them.
137 * @regulator: Supply regulator
138 * @dentry: debugfs dentry pointer of the real device directory (not links).
139 * @dentry_name: Name of the real dentry.
141 * @voltage_tolerance_v1: In percentage, for v1 bindings only.
143 * This is an internal data structure maintaining the link to opps attached to
144 * a device. This structure is not meant to be shared to users as it is
145 * meant for book keeping and private to OPP library.
147 * Because the opp structures can be used from both rcu and srcu readers, we
148 * need to wait for the grace period of both of them before freeing any
149 * resources. And so we have used kfree_rcu() from within call_srcu() handlers.
152 struct list_head node;
154 struct srcu_notifier_head srcu_head;
155 struct rcu_head rcu_head;
156 struct list_head dev_list;
157 struct list_head opp_list;
159 struct device_node *np;
160 unsigned long clock_latency_ns_max;
162 /* For backward compatibility with v1 bindings */
163 unsigned int voltage_tolerance_v1;
166 struct dev_pm_opp *suspend_opp;
168 unsigned int *supported_hw;
169 unsigned int supported_hw_count;
170 const char *prop_name;
171 struct regulator *regulator;
173 #ifdef CONFIG_DEBUG_FS
174 struct dentry *dentry;
175 char dentry_name[NAME_MAX];
179 /* Routines internal to opp core */
180 struct device_opp *_find_device_opp(struct device *dev);
181 struct device_list_opp *_add_list_dev(const struct device *dev,
182 struct device_opp *dev_opp);
183 struct device_node *_of_get_opp_desc_node(struct device *dev);
185 #ifdef CONFIG_DEBUG_FS
186 void opp_debug_remove_one(struct dev_pm_opp *opp);
187 int opp_debug_create_one(struct dev_pm_opp *opp, struct device_opp *dev_opp);
188 int opp_debug_register(struct device_list_opp *list_dev,
189 struct device_opp *dev_opp);
190 void opp_debug_unregister(struct device_list_opp *list_dev,
191 struct device_opp *dev_opp);
193 static inline void opp_debug_remove_one(struct dev_pm_opp *opp) {}
195 static inline int opp_debug_create_one(struct dev_pm_opp *opp,
196 struct device_opp *dev_opp)
198 static inline int opp_debug_register(struct device_list_opp *list_dev,
199 struct device_opp *dev_opp)
202 static inline void opp_debug_unregister(struct device_list_opp *list_dev,
203 struct device_opp *dev_opp)
205 #endif /* DEBUG_FS */
207 #endif /* __DRIVER_OPP_H__ */