From 9080a35160e9b4b469c95518b1350cdc77912ecf Mon Sep 17 00:00:00 2001 From: Jean-Christophe PLAGNIOL-VILLARD Date: Tue, 3 Aug 2010 14:53:38 +0200 Subject: clock: Introduce clock framework from Linux Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD Signed-off-by: Sascha Hauer --- include/linux/clk.h | 158 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 158 insertions(+) create mode 100644 include/linux/clk.h (limited to 'include') diff --git a/include/linux/clk.h b/include/linux/clk.h new file mode 100644 index 0000000000..1478c97381 --- /dev/null +++ b/include/linux/clk.h @@ -0,0 +1,158 @@ +/* + * 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 + +struct device_d; + +/* + * 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_d *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. + * + * 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. + * + * 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); + + +/* + * 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); + +/** + * 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_d *dev); + +#endif -- cgit v1.2.3