clk: provide prepare/unprepare functions (40d3e0f4) · Commits · 戴 / test

include/linux/clk.h

+43 −0

Original line number	Diff line number	Diff line
		@@ -11,6 +11,8 @@
		#ifndef __LINUX_CLK_H
		#define __LINUX_CLK_H

		#include <linux/kernel.h>

		struct device;

		/*
		@@ -40,12 +42,32 @@ struct clk;
		*/
		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);
		@@ -57,6 +79,8 @@ int clk_enable(struct clk *clk);
		* 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
		@@ -64,6 +88,25 @@ int clk_enable(struct clk *clk);
		*/
		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_get_rate - obtain the current clock rate (in Hz) for a clock source.
		* This is only valid once the clock source has been enabled.

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