path: root/include/linux/clk-provider.h

/* SPDX-License-Identifier: GPL-2.0 */
/*
 *  Copyright (c) 2010-2011 Jeremy Kerr <jeremy.kerr@canonical.com>
 *  Copyright (C) 2011-2012 Linaro Ltd <mturquette@linaro.org>
 */
#ifndef __LINUX_CLK_PROVIDER_H
#define __LINUX_CLK_PROVIDER_H

#include <linux/of.h>
#include <linux/of_clk.h>

/*
 * flags used across common struct clk.  these flags should only affect the
 * top-level framework.  custom flags for dealing with hardware specifics
 * belong in struct clk_foo
 *
 * Please update clk_flags[] in drivers/clk/clk.c when making changes here!
 */
#define CLK_SET_RATE_GATE	BIT(0) /* must be gated across rate change */
#define CLK_SET_PARENT_GATE	BIT(1) /* must be gated across re-parent */
#define CLK_SET_RATE_PARENT	BIT(2) /* propagate rate change up one level */
#define CLK_IGNORE_UNUSED	BIT(3) /* do not gate even if unused */
				/* unused */
				/* unused */
#define CLK_GET_RATE_NOCACHE	BIT(6) /* do not use the cached clk rate */
#define CLK_SET_RATE_NO_REPARENT BIT(7) /* don't re-parent on rate change */
#define CLK_GET_ACCURACY_NOCACHE BIT(8) /* do not use the cached clk accuracy */
#define CLK_RECALC_NEW_RATES	BIT(9) /* recalc rates after notifications */
#define CLK_SET_RATE_UNGATE	BIT(10) /* clock needs to run to set rate */
#define CLK_IS_CRITICAL		BIT(11) /* do not gate, ever */
/* parents need enable during gate/ungate, set rate and re-parent */
#define CLK_OPS_PARENT_ENABLE	BIT(12)
/* duty cycle call may be forwarded to the parent clock */
#define CLK_DUTY_CYCLE_PARENT	BIT(13)

struct clk;
struct clk_hw;
struct clk_core;
struct dentry;

/**
 * struct clk_rate_request - Structure encoding the clk constraints that
 * a clock user might require.
 *
 * Should be initialized by calling clk_hw_init_rate_request().
 *
 * @rate:		Requested clock rate. This field will be adjusted by
 *			clock drivers according to hardware capabilities.
 * @min_rate:		Minimum rate imposed by clk users.
 * @max_rate:		Maximum rate imposed by clk users.
 * @best_parent_rate:	The best parent rate a parent can provide to fulfill the
 *			requested constraints.
 * @best_parent_hw:	The most appropriate parent clock that fulfills the
 *			requested constraints.
 *
 */
struct clk_rate_request {
	unsigned long rate;
	unsigned long min_rate;
	unsigned long max_rate;
	unsigned long best_parent_rate;
	struct clk_hw *best_parent_hw;
};

void clk_hw_init_rate_request(const struct clk_hw *hw,
			      struct clk_rate_request *req,
			      unsigned long rate);
void clk_hw_forward_rate_request(const struct clk_hw *core,
				 const struct clk_rate_request *old_req,
				 const struct clk_hw *parent,
				 struct clk_rate_request *req,
				 unsigned long parent_rate);

/**
 * struct clk_duty - Structure encoding the duty cycle ratio of a clock
 *
 * @num:	Numerator of the duty cycle ratio
 * @den:	Denominator of the duty cycle ratio
 */
struct clk_duty {
	unsigned int num;
	unsigned int den;
};

/**
 * struct clk_ops -  Callback operations for hardware clocks; these are to
 * be provided by the clock implementation, and will be called by drivers
 * through the clk_* api.
 *
 * @prepare:	Prepare the clock for enabling. This must not return until
 *		the clock is fully prepared, and it's safe to call clk_enable.
 *		This callback is intended to allow clock implementations to
 *		do any initialisation that may sleep. Called with
 *		prepare_lock held.
 *
 * @unprepare:	Release the clock from its prepared state. This will typically
 *		undo any work done in the @prepare callback. Called with
 *		prepare_lock held.
 *
 * @is_prepared: Queries the hardware to determine if the clock is prepared.
 *		This function is allowed to sleep. Optional, if this op is not
 *		set then the prepare count will be used.
 *
 * @unprepare_unused: Unprepare the clock atomically.  Only called from
 *		clk_disable_unused for prepare clocks with special needs.
 *		Called with prepare mutex held. This function may sleep.
 *
 * @enable:	Enable the clock atomically. This must not return until the
 *		clock is generating a valid clock signal, usable by consumer
 *		devices. Called with enable_lock held. This function must not
 *		sleep.
 *
 * @disable:	Disable the clock atomically. Called with enable_lock held.
 *		This function must not sleep.
 *
 * @is_enabled:	Queries the hardware to determine if the clock is enabled.
 *		This function must not sleep. Optional, if this op is not
 *		set then the enable count will be used.
 *
 * @disable_unused: Disable the clock atomically.  Only called from
 *		clk_disable_unused for gate clocks with special needs.
 *		Called with enable_lock held.  This function must not
 *		sleep.
 *
 * @save_context: Save the context of the clock in prepration for poweroff.
 *
 * @restore_context: Restore the context of the clock after a restoration
 *		of power.
 *
 * @recalc_rate: Recalculate the rate of this clock, by querying hardware. The
 *		parent rate is an input parameter.  It is up to the caller to
 *		ensure that the prepare_mutex is held across this call. If the
 *		driver cannot figure out a rate for this clock, it must return
 *		0. Returns the calculated rate. Optional, but recommended - if
 *		this op is not set then clock rate will be initialized to 0.
 *
 * @round_rate:	Given a target rate as input, returns the closest rate actually
 *		supported by the clock. The parent rate is an input/output
 *		parameter.
 *
 * @determine_rate: Given a target rate as input, returns the closest rate
 *		act