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Diffstat (limited to 'kernel/include/linux/clk.h')
| -rw-r--r-- | kernel/include/linux/clk.h | 506 |
1 files changed, 506 insertions, 0 deletions
diff --git a/kernel/include/linux/clk.h b/kernel/include/linux/clk.h new file mode 100644 index 000000000..68c16a6be --- /dev/null +++ b/kernel/include/linux/clk.h @@ -0,0 +1,506 @@ +/* + * 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); + +/** + * clk_is_match - check if two clk's point to the same hardware clock + * @p: clk compared against q + * @q: clk compared against p + * + * Returns true if the two struct clk pointers both point to the same hardware + * clock node. Put differently, returns true if struct clk *p and struct clk *q + * share the same struct clk_core object. + * + * Returns false otherwise. Note that two NULL clks are treated as matching. + */ +bool clk_is_match(const struct clk *p, const struct clk *q); + +#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; +} + +static inline bool clk_is_match(const struct clk *p, const struct clk *q) +{ + return p == q; +} + +#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 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_has_parent - check if a clock is a possible parent for another + * @clk: clock source + * @parent: parent clock source + * + * This function can be used in drivers that need to check that a clock can be + * the parent of another without actually changing the parent. + * + * Returns true if @parent is a possible parent for @clk, false otherwise. + */ +bool clk_has_parent(struct clk *clk, struct clk *parent); + +/** + * clk_set_rate_range - set a rate range for a clock source + * @clk: clock source + * @min: desired minimum clock rate in Hz, inclusive + * @max: desired maximum clock rate in Hz, inclusive + * + * Returns success (0) or negative errno. + */ +int clk_set_rate_range(struct clk *clk, unsigned long min, unsigned long max); + +/** + * clk_set_min_rate - set a minimum clock rate for a clock source + * @clk: clock source + * @rate: desired minimum clock rate in Hz, inclusive + * + * Returns success (0) or negative errno. + */ +int clk_set_min_rate(struct clk *clk, unsigned long rate); + +/** + * clk_set_max_rate - set a maximum clock rate for a clock source + * @clk: clock source + * @rate: desired maximum clock rate in Hz, inclusive + * + * Returns success (0) or negative errno. + */ +int clk_set_max_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 bool clk_has_parent(struct clk *clk, struct clk *parent) +{ + return true; +} + +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 |