/* *  linux/include/linux/clk.h * *  Copyright (C) 2004 ARM Limited. *  Written by Deep Blue Solutions Limited. *  Copyright (C) 2011-2012 Linaro Ltd <mturquette@linaro.org> * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. */#ifndef __LINUX_CLK_H#define __LINUX_CLK_H #include <linux/err.h>#include <linux/kernel.h>#include <linux/notifier.h> struct device; struct clk; #ifdef CONFIG_COMMON_CLK /** * DOC: clk notifier callback types * * PRE_RATE_CHANGE - called immediately before the clk rate is changed, *     to indicate that the rate change will proceed.  Drivers must *     immediately terminate any operations that will be affected by the *     rate change.  Callbacks may either return NOTIFY_DONE, NOTIFY_OK, *     NOTIFY_STOP or NOTIFY_BAD. * * ABORT_RATE_CHANGE: called if the rate change failed for some reason *     after PRE_RATE_CHANGE.  In this case, all registered notifiers on *     the clk will be called with ABORT_RATE_CHANGE. Callbacks must *     always return NOTIFY_DONE or NOTIFY_OK. * * POST_RATE_CHANGE - called after the clk rate change has successfully *     completed.  Callbacks must always return NOTIFY_DONE or NOTIFY_OK. * */#define PRE_RATE_CHANGE			BIT(0)#define POST_RATE_CHANGE		BIT(1)#define ABORT_RATE_CHANGE		BIT(2) /** * struct clk_notifier - associate a clk with a notifier * @clk: struct clk * to associate the notifier with * @notifier_head: a blocking_notifier_head for this clk * @node: linked list pointers * * A list of struct clk_notifier is maintained by the notifier code. * An entry is created whenever code registers the first notifier on a * particular @clk.  Future notifiers on that @clk are added to the * @notifier_head. */struct clk_notifier {	struct clk			*clk;	struct srcu_notifier_head	notifier_head;	struct list_head		node;}; /** * struct clk_notifier_data - rate data to pass to the notifier callback * @clk: struct clk * being changed * @old_rate: previous rate of this clk * @new_rate: new rate of this clk * * For a pre-notifier, old_rate is the clk's rate before this rate * change, and new_rate is what the rate will be in the future.  For a * post-notifier, old_rate and new_rate are both set to the clk's * current rate (this was done to optimize the implementation). */struct clk_notifier_data {	struct clk		*clk;	unsigned long		old_rate;	unsigned long		new_rate;}; /** * clk_notifier_register: register a clock rate-change notifier callback * @clk: clock whose rate we are interested in * @nb: notifier block with callback function pointer * * ProTip: debugging across notifier chains can be frustrating. Make sure that * your notifier callback function prints a nice big warning in case of * failure. */int clk_notifier_register(struct clk *clk, struct notifier_block *nb); /** * clk_notifier_unregister: unregister a clock rate-change notifier callback * @clk: clock whose rate we are no longer interested in * @nb: notifier block which will be unregistered */int clk_notifier_unregister(struct clk *clk, struct notifier_block *nb); /** * clk_get_accuracy - obtain the clock accuracy in ppb (parts per billion) *		      for a clock source. * @clk: clock source * * This gets the clock source accuracy expressed in ppb. * A perfect clock returns 0. */long clk_get_accuracy(struct clk *clk); /** * clk_set_phase - adjust the phase shift of a clock signal * @clk: clock signal source * @degrees: number of degrees the signal is shifted * * Shifts the phase of a clock signal by the specified degrees. Returns 0 on * success, -EERROR otherwise. */int clk_set_phase(struct clk *clk, int degrees); /** * clk_get_phase - return the phase shift of a clock signal * @clk: clock signal source * * Returns the phase shift of a clock node in degrees, otherwise returns * -EERROR. */int clk_get_phase(struct clk *clk); #else static inline long clk_get_accuracy(struct clk *clk){	return -ENOTSUPP;} static inline long clk_set_phase(struct clk *clk, int phase){	return -ENOTSUPP;} static inline long clk_get_phase(struct clk *clk){	return -ENOTSUPP;} #endif /** * clk_prepare - prepare a clock source * @clk: clock source * * This prepares the clock source for use. * * Must not be called from within atomic context. */#ifdef CONFIG_HAVE_CLK_PREPAREint clk_prepare(struct clk *clk);#elsestatic inline int clk_prepare(struct clk *clk){	might_sleep();	return 0;}#endif /** * clk_unprepare - undo preparation of a clock source * @clk: clock source * * This undoes a previously prepared clock.  The caller must balance * the number of prepare and unprepare calls. * * Must not be called from within atomic context. */#ifdef CONFIG_HAVE_CLK_PREPAREvoid clk_unprepare(struct clk *clk);#elsestatic inline void clk_unprepare(struct clk *clk){	might_sleep();}#endif #ifdef CONFIG_HAVE_CLK/** * clk_get - lookup and obtain a reference to a clock producer. * @dev: device for clock "consumer" * @id: clock consumer ID * * Returns a struct clk corresponding to the clock producer, or * valid IS_ERR() condition containing errno.  The implementation * uses @dev and @id to determine the clock consumer, and thereby * the clock producer.  (IOW, @id may be identical strings, but * clk_get may return different clock producers depending on @dev.) * * Drivers must assume that the clock source is not enabled. * * clk_get should not be called from within interrupt context. */struct clk *clk_get(struct device *dev, const char *id); /** * devm_clk_get - lookup and obtain a managed reference to a clock producer. * @dev: device for clock "consumer" * @id: clock consumer ID * * Returns a struct clk corresponding to the clock producer, or * valid IS_ERR() condition containing errno.  The implementation * uses @dev and @id to determine the clock consumer, and thereby * the clock producer.  (IOW, @id may be identical strings, but * clk_get may return different clock producers depending on @dev.) * * Drivers must assume that the clock source is not enabled. * * devm_clk_get should not be called from within interrupt context. * * The clock will automatically be freed when the device is unbound * from the bus. */struct clk *devm_clk_get(struct device *dev, const char *id); /** * clk_enable - inform the system when the clock source should be running. * @clk: clock source * * If the clock can not be enabled/disabled, this should return success. * * May be called from atomic contexts. * * Returns success (0) or negative errno. */int clk_enable(struct clk *clk); /** * clk_disable - inform the system when the clock source is no longer required. * @clk: clock source * * Inform the system that a clock source is no longer required by * a driver and may be shut down. * * May be called from atomic contexts. * * Implementation detail: if the clock source is shared between * multiple drivers, clk_enable() calls must be balanced by the * same number of clk_disable() calls for the clock source to be * disabled. */void clk_disable(struct clk *clk); /** * clk_get_rate - obtain the current clock rate (in Hz) for a clock source. *		  This is only valid once the clock source has been enabled. * @clk: clock source */unsigned long clk_get_rate(struct clk *clk); /** * clk_put	- "free" the clock source * @clk: clock source * * Note: drivers must ensure that all clk_enable calls made on this * clock source are balanced by clk_disable calls prior to calling * this function. * * clk_put should not be called from within interrupt context. */void clk_put(struct clk *clk); /** * devm_clk_put	- "free" a managed clock source * @dev: device used to acquire the clock * @clk: clock source acquired with devm_clk_get() * * Note: drivers must ensure that all clk_enable calls made on this * clock source are balanced by clk_disable calls prior to calling * this function. * * clk_put should not be called from within interrupt context. */void devm_clk_put(struct device *dev, struct clk *clk); /* * The remaining APIs are optional for machine class support. */  /** * clk_round_rate - adjust a rate to the exact rate a clock can provide * @clk: clock source * @rate: desired clock rate in Hz * * Returns rounded clock rate in Hz, or negative errno. */long clk_round_rate(struct clk *clk, unsigned long rate); /** * clk_set_rate - set the clock rate for a clock source * @clk: clock source * @rate: desired clock rate in Hz * * Returns success (0) or negative errno. */int clk_set_rate(struct clk *clk, unsigned long rate); /** * clk_set_parent - set the parent clock source for this clock * @clk: clock source * @parent: parent clock source * * Returns success (0) or negative errno. */int clk_set_parent(struct clk *clk, struct clk *parent); /** * clk_get_parent - get the parent clock source for this clock * @clk: clock source * * Returns struct clk corresponding to parent clock source, or * valid IS_ERR() condition containing errno. */struct clk *clk_get_parent(struct clk *clk); /** * clk_get_sys - get a clock based upon the device name * @dev_id: device name * @con_id: connection ID * * Returns a struct clk corresponding to the clock producer, or * valid IS_ERR() condition containing errno.  The implementation * uses @dev_id and @con_id to determine the clock consumer, and * thereby the clock producer. In contrast to clk_get() this function * takes the device name instead of the device itself for identification. * * Drivers must assume that the clock source is not enabled. * * clk_get_sys should not be called from within interrupt context. */struct clk *clk_get_sys(const char *dev_id, const char *con_id); #else /* !CONFIG_HAVE_CLK */ static inline struct clk *clk_get(struct device *dev, const char *id){	return NULL;} static inline struct clk *devm_clk_get(struct device *dev, const char *id){	return NULL;} static inline void clk_put(struct clk *clk) {} static inline void devm_clk_put(struct device *dev, struct clk *clk) {} static inline int clk_enable(struct clk *clk){	return 0;} static inline void clk_disable(struct clk *clk) {} static inline unsigned long clk_get_rate(struct clk *clk){	return 0;} static inline int clk_set_rate(struct clk *clk, unsigned long rate){	return 0;} static inline long clk_round_rate(struct clk *clk, unsigned long rate){	return 0;} static inline int clk_set_parent(struct clk *clk, struct clk *parent){	return 0;} static inline struct clk *clk_get_parent(struct clk *clk){	return NULL;} #endif /* clk_prepare_enable helps cases using clk_enable in non-atomic context. */static inline int clk_prepare_enable(struct clk *clk){	int ret; 	ret = clk_prepare(clk);	if (ret)		return ret;	ret = clk_enable(clk);	if (ret)		clk_unprepare(clk); 	return ret;} /* clk_disable_unprepare helps cases using clk_disable in non-atomic context. */static inline void clk_disable_unprepare(struct clk *clk){	clk_disable(clk);	clk_unprepare(clk);} /** * clk_add_alias - add a new clock alias * @alias: name for clock alias * @alias_dev_name: device name * @id: platform specific clock name * @dev: device * * Allows using generic clock names for drivers by adding a new alias. * Assumes clkdev, see clkdev.h for more info. */int clk_add_alias(const char *alias, const char *alias_dev_name, char *id,			struct device *dev); struct device_node;struct of_phandle_args; #if defined(CONFIG_OF) && defined(CONFIG_COMMON_CLK)struct clk *of_clk_get(struct device_node *np, int index);struct clk *of_clk_get_by_name(struct device_node *np, const char *name);struct clk *of_clk_get_from_provider(struct of_phandle_args *clkspec);#elsestatic inline struct clk *of_clk_get(struct device_node *np, int index){	return ERR_PTR(-ENOENT);}static inline struct clk *of_clk_get_by_name(struct device_node *np,					     const char *name){	return ERR_PTR(-ENOENT);}#endif #endif