/* * linux/include/linux/clk.h * * Copyright (C) 2004 ARM Limited. * Written by Deep Blue Solutions Limited. * * 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/kernel.h> struct device; /* * The base API. */ /* * struct clk - an machine class defined object / cookie. */ struct clk; /** * clk_get - lookup and obtain a reference to a clock producer. * @dev: device for clock "consumer" * @id: clock comsumer 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); /** * 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_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_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 /* 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_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); /* * 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 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); /** * 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); #endif