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523 lines
14 KiB
523 lines
14 KiB
/* |
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* linux/include/linux/clk.h |
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* |
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* Copyright (C) 2004 ARM Limited. |
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* Written by Deep Blue Solutions Limited. |
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* Copyright (C) 2011-2012 Linaro Ltd <[email protected]> |
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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 __LINUX_CLK_H |
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#define __LINUX_CLK_H |
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#include <linux/err.h> |
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#include <linux/kernel.h> |
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#include <linux/notifier.h> |
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struct device; |
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struct clk; |
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/** |
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* DOC: clk notifier callback types |
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* |
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* PRE_RATE_CHANGE - called immediately before the clk rate is changed, |
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* to indicate that the rate change will proceed. Drivers must |
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* immediately terminate any operations that will be affected by the |
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* rate change. Callbacks may either return NOTIFY_DONE, NOTIFY_OK, |
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* NOTIFY_STOP or NOTIFY_BAD. |
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* |
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* ABORT_RATE_CHANGE: called if the rate change failed for some reason |
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* after PRE_RATE_CHANGE. In this case, all registered notifiers on |
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* the clk will be called with ABORT_RATE_CHANGE. Callbacks must |
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* always return NOTIFY_DONE or NOTIFY_OK. |
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* |
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* POST_RATE_CHANGE - called after the clk rate change has successfully |
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* completed. Callbacks must always return NOTIFY_DONE or NOTIFY_OK. |
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* |
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*/ |
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#define PRE_RATE_CHANGE BIT(0) |
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#define POST_RATE_CHANGE BIT(1) |
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#define ABORT_RATE_CHANGE BIT(2) |
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/** |
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* struct clk_notifier - associate a clk with a notifier |
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* @clk: struct clk * to associate the notifier with |
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* @notifier_head: a blocking_notifier_head for this clk |
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* @node: linked list pointers |
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* |
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* A list of struct clk_notifier is maintained by the notifier code. |
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* An entry is created whenever code registers the first notifier on a |
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* particular @clk. Future notifiers on that @clk are added to the |
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* @notifier_head. |
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*/ |
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struct clk_notifier { |
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struct clk *clk; |
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struct srcu_notifier_head notifier_head; |
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struct list_head node; |
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}; |
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/** |
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* struct clk_notifier_data - rate data to pass to the notifier callback |
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* @clk: struct clk * being changed |
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* @old_rate: previous rate of this clk |
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* @new_rate: new rate of this clk |
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* |
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* For a pre-notifier, old_rate is the clk's rate before this rate |
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* change, and new_rate is what the rate will be in the future. For a |
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* post-notifier, old_rate and new_rate are both set to the clk's |
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* current rate (this was done to optimize the implementation). |
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*/ |
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struct clk_notifier_data { |
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struct clk *clk; |
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unsigned long old_rate; |
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unsigned long new_rate; |
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}; |
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#ifdef CONFIG_COMMON_CLK |
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/** |
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* clk_notifier_register: register a clock rate-change notifier callback |
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* @clk: clock whose rate we are interested in |
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* @nb: notifier block with callback function pointer |
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* |
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* ProTip: debugging across notifier chains can be frustrating. Make sure that |
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* your notifier callback function prints a nice big warning in case of |
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* failure. |
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*/ |
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int clk_notifier_register(struct clk *clk, struct notifier_block *nb); |
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/** |
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* clk_notifier_unregister: unregister a clock rate-change notifier callback |
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* @clk: clock whose rate we are no longer interested in |
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* @nb: notifier block which will be unregistered |
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*/ |
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int clk_notifier_unregister(struct clk *clk, struct notifier_block *nb); |
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/** |
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* clk_get_accuracy - obtain the clock accuracy in ppb (parts per billion) |
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* for a clock source. |
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* @clk: clock source |
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* |
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* This gets the clock source accuracy expressed in ppb. |
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* A perfect clock returns 0. |
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*/ |
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long clk_get_accuracy(struct clk *clk); |
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/** |
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* clk_set_phase - adjust the phase shift of a clock signal |
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* @clk: clock signal source |
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* @degrees: number of degrees the signal is shifted |
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* |
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* Shifts the phase of a clock signal by the specified degrees. Returns 0 on |
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* success, -EERROR otherwise. |
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*/ |
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int clk_set_phase(struct clk *clk, int degrees); |
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/** |
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* clk_get_phase - return the phase shift of a clock signal |
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* @clk: clock signal source |
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* |
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* Returns the phase shift of a clock node in degrees, otherwise returns |
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* -EERROR. |
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*/ |
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int clk_get_phase(struct clk *clk); |
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/** |
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* clk_is_match - check if two clk's point to the same hardware clock |
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* @p: clk compared against q |
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* @q: clk compared against p |
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* |
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* Returns true if the two struct clk pointers both point to the same hardware |
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* clock node. Put differently, returns true if struct clk *p and struct clk *q |
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* share the same struct clk_core object. |
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* |
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* Returns false otherwise. Note that two NULL clks are treated as matching. |
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*/ |
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bool clk_is_match(const struct clk *p, const struct clk *q); |
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#else |
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static inline int clk_notifier_register(struct clk *clk, |
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struct notifier_block *nb) |
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{ |
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return -ENOTSUPP; |
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} |
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static inline int clk_notifier_unregister(struct clk *clk, |
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struct notifier_block *nb) |
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{ |
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return -ENOTSUPP; |
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} |
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static inline long clk_get_accuracy(struct clk *clk) |
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{ |
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return -ENOTSUPP; |
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} |
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static inline long clk_set_phase(struct clk *clk, int phase) |
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{ |
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return -ENOTSUPP; |
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} |
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static inline long clk_get_phase(struct clk *clk) |
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{ |
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return -ENOTSUPP; |
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} |
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static inline bool clk_is_match(const struct clk *p, const struct clk *q) |
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{ |
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return p == q; |
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} |
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#endif |
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/** |
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* clk_prepare - prepare a clock source |
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* @clk: clock source |
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* |
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* This prepares the clock source for use. |
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* |
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* Must not be called from within atomic context. |
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*/ |
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#ifdef CONFIG_HAVE_CLK_PREPARE |
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int clk_prepare(struct clk *clk); |
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#else |
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static inline int clk_prepare(struct clk *clk) |
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{ |
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might_sleep(); |
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return 0; |
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} |
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#endif |
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/** |
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* clk_unprepare - undo preparation of a clock source |
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* @clk: clock source |
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* |
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* This undoes a previously prepared clock. The caller must balance |
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* the number of prepare and unprepare calls. |
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* |
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* Must not be called from within atomic context. |
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*/ |
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#ifdef CONFIG_HAVE_CLK_PREPARE |
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void clk_unprepare(struct clk *clk); |
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#else |
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static inline void clk_unprepare(struct clk *clk) |
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{ |
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might_sleep(); |
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} |
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#endif |
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#ifdef CONFIG_HAVE_CLK |
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/** |
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* clk_get - lookup and obtain a reference to a clock producer. |
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* @dev: device for clock "consumer" |
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* @id: clock consumer ID |
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* |
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* Returns a struct clk corresponding to the clock producer, or |
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* valid IS_ERR() condition containing errno. The implementation |
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* uses @dev and @id to determine the clock consumer, and thereby |
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* the clock producer. (IOW, @id may be identical strings, but |
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* clk_get may return different clock producers depending on @dev.) |
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* |
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* Drivers must assume that the clock source is not enabled. |
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* |
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* clk_get should not be called from within interrupt context. |
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*/ |
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struct clk *clk_get(struct device *dev, const char *id); |
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/** |
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* devm_clk_get - lookup and obtain a managed reference to a clock producer. |
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* @dev: device for clock "consumer" |
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* @id: clock consumer ID |
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* |
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* Returns a struct clk corresponding to the clock producer, or |
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* valid IS_ERR() condition containing errno. The implementation |
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* uses @dev and @id to determine the clock consumer, and thereby |
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* the clock producer. (IOW, @id may be identical strings, but |
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* clk_get may return different clock producers depending on @dev.) |
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* |
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* Drivers must assume that the clock source is not enabled. |
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* |
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* devm_clk_get should not be called from within interrupt context. |
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* |
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* The clock will automatically be freed when the device is unbound |
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* from the bus. |
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*/ |
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struct clk *devm_clk_get(struct device *dev, const char *id); |
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/** |
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* clk_enable - inform the system when the clock source should be running. |
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* @clk: clock source |
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* |
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* If the clock can not be enabled/disabled, this should return success. |
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* |
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* May be called from atomic contexts. |
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* |
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* Returns success (0) or negative errno. |
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*/ |
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int clk_enable(struct clk *clk); |
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/** |
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* clk_disable - inform the system when the clock source is no longer required. |
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* @clk: clock source |
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* |
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* Inform the system that a clock source is no longer required by |
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* a driver and may be shut down. |
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* |
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* May be called from atomic contexts. |
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* |
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* Implementation detail: if the clock source is shared between |
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* multiple drivers, clk_enable() calls must be balanced by the |
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* same number of clk_disable() calls for the clock source to be |
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* disabled. |
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*/ |
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void clk_disable(struct clk *clk); |
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/** |
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* clk_get_rate - obtain the current clock rate (in Hz) for a clock source. |
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* This is only valid once the clock source has been enabled. |
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* @clk: clock source |
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*/ |
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unsigned long clk_get_rate(struct clk *clk); |
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/** |
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* clk_put - "free" the clock source |
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* @clk: clock source |
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* |
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* Note: drivers must ensure that all clk_enable calls made on this |
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* clock source are balanced by clk_disable calls prior to calling |
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* this function. |
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* |
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* clk_put should not be called from within interrupt context. |
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*/ |
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void clk_put(struct clk *clk); |
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/** |
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* devm_clk_put - "free" a managed clock source |
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* @dev: device used to acquire the clock |
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* @clk: clock source acquired with devm_clk_get() |
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* |
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* Note: drivers must ensure that all clk_enable calls made on this |
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* clock source are balanced by clk_disable calls prior to calling |
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* this function. |
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* |
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* clk_put should not be called from within interrupt context. |
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*/ |
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void devm_clk_put(struct device *dev, struct clk *clk); |
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/* |
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* The remaining APIs are optional for machine class support. |
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*/ |
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/** |
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* clk_round_rate - adjust a rate to the exact rate a clock can provide |
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* @clk: clock source |
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* @rate: desired clock rate in Hz |
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* |
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* This answers the question "if I were to pass @rate to clk_set_rate(), |
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* what clock rate would I end up with?" without changing the hardware |
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* in any way. In other words: |
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* |
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* rate = clk_round_rate(clk, r); |
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* |
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* and: |
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* |
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* clk_set_rate(clk, r); |
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* rate = clk_get_rate(clk); |
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* |
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* are equivalent except the former does not modify the clock hardware |
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* in any way. |
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* |
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* Returns rounded clock rate in Hz, or negative errno. |
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*/ |
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long clk_round_rate(struct clk *clk, unsigned long rate); |
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/** |
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* clk_set_rate - set the clock rate for a clock source |
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* @clk: clock source |
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* @rate: desired clock rate in Hz |
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* |
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* Returns success (0) or negative errno. |
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*/ |
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int clk_set_rate(struct clk *clk, unsigned long rate); |
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/** |
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* clk_has_parent - check if a clock is a possible parent for another |
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* @clk: clock source |
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* @parent: parent clock source |
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* |
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* This function can be used in drivers that need to check that a clock can be |
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* the parent of another without actually changing the parent. |
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* |
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* Returns true if @parent is a possible parent for @clk, false otherwise. |
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*/ |
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bool clk_has_parent(struct clk *clk, struct clk *parent); |
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/** |
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* clk_set_rate_range - set a rate range for a clock source |
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* @clk: clock source |
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* @min: desired minimum clock rate in Hz, inclusive |
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* @max: desired maximum clock rate in Hz, inclusive |
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* |
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* Returns success (0) or negative errno. |
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*/ |
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int clk_set_rate_range(struct clk *clk, unsigned long min, unsigned long max); |
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/** |
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* clk_set_min_rate - set a minimum clock rate for a clock source |
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* @clk: clock source |
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* @rate: desired minimum clock rate in Hz, inclusive |
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* |
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* Returns success (0) or negative errno. |
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*/ |
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int clk_set_min_rate(struct clk *clk, unsigned long rate); |
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/** |
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* clk_set_max_rate - set a maximum clock rate for a clock source |
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* @clk: clock source |
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* @rate: desired maximum clock rate in Hz, inclusive |
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* |
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* Returns success (0) or negative errno. |
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*/ |
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int clk_set_max_rate(struct clk *clk, unsigned long rate); |
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/** |
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* clk_set_parent - set the parent clock source for this clock |
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* @clk: clock source |
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* @parent: parent clock source |
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* |
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* Returns success (0) or negative errno. |
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*/ |
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int clk_set_parent(struct clk *clk, struct clk *parent); |
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/** |
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* clk_get_parent - get the parent clock source for this clock |
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* @clk: clock source |
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* |
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* Returns struct clk corresponding to parent clock source, or |
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* valid IS_ERR() condition containing errno. |
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*/ |
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struct clk *clk_get_parent(struct clk *clk); |
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/** |
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* clk_get_sys - get a clock based upon the device name |
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* @dev_id: device name |
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* @con_id: connection ID |
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* |
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* Returns a struct clk corresponding to the clock producer, or |
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* valid IS_ERR() condition containing errno. The implementation |
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* uses @dev_id and @con_id to determine the clock consumer, and |
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* thereby the clock producer. In contrast to clk_get() this function |
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* takes the device name instead of the device itself for identification. |
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* |
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* Drivers must assume that the clock source is not enabled. |
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* |
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* clk_get_sys should not be called from within interrupt context. |
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*/ |
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struct clk *clk_get_sys(const char *dev_id, const char *con_id); |
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#else /* !CONFIG_HAVE_CLK */ |
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static inline struct clk *clk_get(struct device *dev, const char *id) |
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{ |
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return NULL; |
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} |
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static inline struct clk *devm_clk_get(struct device *dev, const char *id) |
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{ |
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return NULL; |
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} |
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static inline void clk_put(struct clk *clk) {} |
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static inline void devm_clk_put(struct device *dev, struct clk *clk) {} |
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static inline int clk_enable(struct clk *clk) |
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{ |
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return 0; |
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} |
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static inline void clk_disable(struct clk *clk) {} |
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static inline unsigned long clk_get_rate(struct clk *clk) |
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{ |
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return 0; |
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} |
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static inline int clk_set_rate(struct clk *clk, unsigned long rate) |
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{ |
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return 0; |
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} |
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static inline long clk_round_rate(struct clk *clk, unsigned long rate) |
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{ |
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return 0; |
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} |
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static inline bool clk_has_parent(struct clk *clk, struct clk *parent) |
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{ |
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return true; |
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} |
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static inline int clk_set_parent(struct clk *clk, struct clk *parent) |
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{ |
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return 0; |
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} |
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static inline struct clk *clk_get_parent(struct clk *clk) |
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{ |
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return NULL; |
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} |
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static inline struct clk *clk_get_sys(const char *dev_id, const char *con_id) |
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{ |
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return NULL; |
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} |
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#endif |
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/* clk_prepare_enable helps cases using clk_enable in non-atomic context. */ |
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static inline int clk_prepare_enable(struct clk *clk) |
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{ |
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int ret; |
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ret = clk_prepare(clk); |
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if (ret) |
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return ret; |
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ret = clk_enable(clk); |
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if (ret) |
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clk_unprepare(clk); |
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return ret; |
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} |
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/* clk_disable_unprepare helps cases using clk_disable in non-atomic context. */ |
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static inline void clk_disable_unprepare(struct clk *clk) |
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{ |
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clk_disable(clk); |
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clk_unprepare(clk); |
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} |
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struct device_node; |
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struct of_phandle_args; |
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#if defined(CONFIG_OF) && defined(CONFIG_COMMON_CLK) |
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struct clk *of_clk_get(struct device_node *np, int index); |
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struct clk *of_clk_get_by_name(struct device_node *np, const char *name); |
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struct clk *of_clk_get_from_provider(struct of_phandle_args *clkspec); |
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#else |
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static inline struct clk *of_clk_get(struct device_node *np, int index) |
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{ |
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return ERR_PTR(-ENOENT); |
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} |
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static inline struct clk *of_clk_get_by_name(struct device_node *np, |
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const char *name) |
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{ |
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return ERR_PTR(-ENOENT); |
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} |
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#endif |
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#endif
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