include/linux/clk-provider.h

Source file repositories/reference/linux-study-clean/include/linux/clk-provider.h

File Facts

System
Linux kernel
Corpus path
include/linux/clk-provider.h
Extension
.h
Size
67756 bytes
Lines
1695
Domain
Core OS
Bucket
Core Kernel Interface
Inferred role
Core OS: implementation source
Status
source implementation candidate

Why This File Exists

Core operating-system implementation surface: boot, tasks, memory, VFS, syscall-facing interfaces, synchronization, credentials, and isolation.

Dependency Surface

Detected Declarations

Annotated Snippet

struct clk_rate_request {
	struct clk_core *core;
	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.
 *
 * @determine_rate: Given a target rate as input, returns the closest rate
 *		actually supported by the clock, and optionally the parent clock
 *		that should be used to provide the clock rate.
 *
 * @set_parent:	Change the input source of this clock; for clocks with multiple
 *		possible parents specify a new parent by passing in the index
 *		as a u8 corresponding to the parent in either the .parent_names
 *		or .parents arrays.  This function in affect translates an
 *		array index into the value programmed into the hardware.

Annotation

Implementation Notes