]>
Commit | Line | Data |
---|---|---|
b2476490 MT |
1 | /* |
2 | * linux/include/linux/clk-provider.h | |
3 | * | |
4 | * Copyright (c) 2010-2011 Jeremy Kerr <jeremy.kerr@canonical.com> | |
5 | * Copyright (C) 2011-2012 Linaro Ltd <mturquette@linaro.org> | |
6 | * | |
7 | * This program is free software; you can redistribute it and/or modify | |
8 | * it under the terms of the GNU General Public License version 2 as | |
9 | * published by the Free Software Foundation. | |
10 | */ | |
11 | #ifndef __LINUX_CLK_PROVIDER_H | |
12 | #define __LINUX_CLK_PROVIDER_H | |
13 | ||
14 | #include <linux/clk.h> | |
15 | ||
16 | #ifdef CONFIG_COMMON_CLK | |
17 | ||
18 | /** | |
19 | * struct clk_hw - handle for traversing from a struct clk to its corresponding | |
20 | * hardware-specific structure. struct clk_hw should be declared within struct | |
21 | * clk_foo and then referenced by the struct clk instance that uses struct | |
22 | * clk_foo's clk_ops | |
23 | * | |
24 | * clk: pointer to the struct clk instance that points back to this struct | |
25 | * clk_hw instance | |
26 | */ | |
27 | struct clk_hw { | |
28 | struct clk *clk; | |
29 | }; | |
30 | ||
31 | /* | |
32 | * flags used across common struct clk. these flags should only affect the | |
33 | * top-level framework. custom flags for dealing with hardware specifics | |
34 | * belong in struct clk_foo | |
35 | */ | |
36 | #define CLK_SET_RATE_GATE BIT(0) /* must be gated across rate change */ | |
37 | #define CLK_SET_PARENT_GATE BIT(1) /* must be gated across re-parent */ | |
38 | #define CLK_SET_RATE_PARENT BIT(2) /* propagate rate change up one level */ | |
39 | #define CLK_IGNORE_UNUSED BIT(3) /* do not gate even if unused */ | |
40 | #define CLK_IS_ROOT BIT(4) /* root clk, has no parent */ | |
41 | ||
42 | /** | |
43 | * struct clk_ops - Callback operations for hardware clocks; these are to | |
44 | * be provided by the clock implementation, and will be called by drivers | |
45 | * through the clk_* api. | |
46 | * | |
47 | * @prepare: Prepare the clock for enabling. This must not return until | |
48 | * the clock is fully prepared, and it's safe to call clk_enable. | |
49 | * This callback is intended to allow clock implementations to | |
50 | * do any initialisation that may sleep. Called with | |
51 | * prepare_lock held. | |
52 | * | |
53 | * @unprepare: Release the clock from its prepared state. This will typically | |
54 | * undo any work done in the @prepare callback. Called with | |
55 | * prepare_lock held. | |
56 | * | |
57 | * @enable: Enable the clock atomically. This must not return until the | |
58 | * clock is generating a valid clock signal, usable by consumer | |
59 | * devices. Called with enable_lock held. This function must not | |
60 | * sleep. | |
61 | * | |
62 | * @disable: Disable the clock atomically. Called with enable_lock held. | |
63 | * This function must not sleep. | |
64 | * | |
65 | * @recalc_rate Recalculate the rate of this clock, by quering hardware. The | |
66 | * parent rate is an input parameter. It is up to the caller to | |
67 | * insure that the prepare_mutex is held across this call. | |
68 | * Returns the calculated rate. Optional, but recommended - if | |
69 | * this op is not set then clock rate will be initialized to 0. | |
70 | * | |
71 | * @round_rate: Given a target rate as input, returns the closest rate actually | |
72 | * supported by the clock. | |
73 | * | |
74 | * @get_parent: Queries the hardware to determine the parent of a clock. The | |
75 | * return value is a u8 which specifies the index corresponding to | |
76 | * the parent clock. This index can be applied to either the | |
77 | * .parent_names or .parents arrays. In short, this function | |
78 | * translates the parent value read from hardware into an array | |
79 | * index. Currently only called when the clock is initialized by | |
80 | * __clk_init. This callback is mandatory for clocks with | |
81 | * multiple parents. It is optional (and unnecessary) for clocks | |
82 | * with 0 or 1 parents. | |
83 | * | |
84 | * @set_parent: Change the input source of this clock; for clocks with multiple | |
85 | * possible parents specify a new parent by passing in the index | |
86 | * as a u8 corresponding to the parent in either the .parent_names | |
87 | * or .parents arrays. This function in affect translates an | |
88 | * array index into the value programmed into the hardware. | |
89 | * Returns 0 on success, -EERROR otherwise. | |
90 | * | |
91 | * @set_rate: Change the rate of this clock. If this callback returns | |
92 | * CLK_SET_RATE_PARENT, the rate change will be propagated to the | |
93 | * parent clock (which may propagate again if the parent clock | |
94 | * also sets this flag). The requested rate of the parent is | |
95 | * passed back from the callback in the second 'unsigned long *' | |
96 | * argument. Note that it is up to the hardware clock's set_rate | |
97 | * implementation to insure that clocks do not run out of spec | |
98 | * when propgating the call to set_rate up to the parent. One way | |
99 | * to do this is to gate the clock (via clk_disable and/or | |
100 | * clk_unprepare) before calling clk_set_rate, then ungating it | |
101 | * afterward. If your clock also has the CLK_GATE_SET_RATE flag | |
102 | * set then this will insure safety. Returns 0 on success, | |
103 | * -EERROR otherwise. | |
104 | * | |
105 | * The clk_enable/clk_disable and clk_prepare/clk_unprepare pairs allow | |
106 | * implementations to split any work between atomic (enable) and sleepable | |
107 | * (prepare) contexts. If enabling a clock requires code that might sleep, | |
108 | * this must be done in clk_prepare. Clock enable code that will never be | |
109 | * called in a sleepable context may be implement in clk_enable. | |
110 | * | |
111 | * Typically, drivers will call clk_prepare when a clock may be needed later | |
112 | * (eg. when a device is opened), and clk_enable when the clock is actually | |
113 | * required (eg. from an interrupt). Note that clk_prepare MUST have been | |
114 | * called before clk_enable. | |
115 | */ | |
116 | struct clk_ops { | |
117 | int (*prepare)(struct clk_hw *hw); | |
118 | void (*unprepare)(struct clk_hw *hw); | |
119 | int (*enable)(struct clk_hw *hw); | |
120 | void (*disable)(struct clk_hw *hw); | |
121 | int (*is_enabled)(struct clk_hw *hw); | |
122 | unsigned long (*recalc_rate)(struct clk_hw *hw, | |
123 | unsigned long parent_rate); | |
124 | long (*round_rate)(struct clk_hw *hw, unsigned long, | |
125 | unsigned long *); | |
126 | int (*set_parent)(struct clk_hw *hw, u8 index); | |
127 | u8 (*get_parent)(struct clk_hw *hw); | |
128 | int (*set_rate)(struct clk_hw *hw, unsigned long); | |
129 | void (*init)(struct clk_hw *hw); | |
130 | }; | |
131 | ||
132 | ||
133 | /** | |
134 | * clk_register - allocate a new clock, register it and return an opaque cookie | |
135 | * @dev: device that is registering this clock | |
136 | * @name: clock name | |
137 | * @ops: operations this clock supports | |
138 | * @hw: link to hardware-specific clock data | |
139 | * @parent_names: array of string names for all possible parents | |
140 | * @num_parents: number of possible parents | |
141 | * @flags: framework-level hints and quirks | |
142 | * | |
143 | * clk_register is the primary interface for populating the clock tree with new | |
144 | * clock nodes. It returns a pointer to the newly allocated struct clk which | |
145 | * cannot be dereferenced by driver code but may be used in conjuction with the | |
146 | * rest of the clock API. | |
147 | */ | |
148 | struct clk *clk_register(struct device *dev, const char *name, | |
149 | const struct clk_ops *ops, struct clk_hw *hw, | |
150 | char **parent_names, u8 num_parents, unsigned long flags); | |
151 | ||
152 | /* helper functions */ | |
153 | const char *__clk_get_name(struct clk *clk); | |
154 | struct clk_hw *__clk_get_hw(struct clk *clk); | |
155 | u8 __clk_get_num_parents(struct clk *clk); | |
156 | struct clk *__clk_get_parent(struct clk *clk); | |
157 | inline int __clk_get_enable_count(struct clk *clk); | |
158 | inline int __clk_get_prepare_count(struct clk *clk); | |
159 | unsigned long __clk_get_rate(struct clk *clk); | |
160 | unsigned long __clk_get_flags(struct clk *clk); | |
161 | int __clk_is_enabled(struct clk *clk); | |
162 | struct clk *__clk_lookup(const char *name); | |
163 | ||
164 | /* | |
165 | * FIXME clock api without lock protection | |
166 | */ | |
167 | int __clk_prepare(struct clk *clk); | |
168 | void __clk_unprepare(struct clk *clk); | |
169 | void __clk_reparent(struct clk *clk, struct clk *new_parent); | |
170 | unsigned long __clk_round_rate(struct clk *clk, unsigned long rate); | |
171 | ||
172 | #endif /* CONFIG_COMMON_CLK */ | |
173 | #endif /* CLK_PROVIDER_H */ |