/* * 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 or * NOTIFY_STOP. * * 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. * * POST_RATE_CHANGE - called after the clk rate change has successfully * completed. Callbacks must always return NOTIFY_DONE. * */ #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; }; int clk_notifier_register(struct clk *clk, struct notifier_block *nb); int clk_notifier_unregister(struct clk *clk, struct notifier_block *nb); #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_PREPARE int clk_prepare(struct clk *clk); #else static 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_PREPARE void clk_unprepare(struct clk *clk); #else static 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 acuqire 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); #else static 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