/*
* linux/include/linux/clk-provider.h
*
* Copyright (c) 2010-2011 Jeremy Kerr <jeremy.kerr@canonical.com>
* Copyright (C) 2011-2012 Linaro Ltd <mturquette@linaro.org>
*
* 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_PROVIDER_H
#define __LINUX_CLK_PROVIDER_H
#include <linux/clk.h>
#ifdef CONFIG_COMMON_CLK
/**
* struct clk_hw - handle for traversing from a struct clk to its corresponding
* hardware-specific structure. struct clk_hw should be declared within struct
* clk_foo and then referenced by the struct clk instance that uses struct
* clk_foo's clk_ops
*
* clk: pointer to the struct clk instance that points back to this struct
* clk_hw instance
*/
struct clk_hw {
struct clk *clk;
};
/*
* 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
*/
#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 */
#define CLK_IS_ROOT BIT(4) /* root clk, has no parent */
/**
* 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.
*
* @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.
*
* @recalc_rate Recalculate the rate of this clock, by quering hardware. The
* parent rate is an input parameter. It is up to the caller to
* insure that the prepare_mutex is held across this call.
* 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.
*
* @get_parent: Queries the hardware to determine the parent of a clock. The
* return value is a u8 which specifies the index corresponding to
* the parent clock. This index can be applied to either the
* .parent_names or .parents arrays. In short, this function
* translates the parent value read from hardware into an array
* index. Currently only called when the clock is initialized by
* __clk_init. This callback is mandatory for clocks with
* multiple parents. It is optional (and unnecessary) for clocks
* with 0 or 1 parents.
*
* @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.
* Returns 0 on success, -EERROR otherwise.
*
* @set_rate: Change the rate of this clock. If this callback returns
* CLK_SET_RATE_PARENT, the rate change will be propagated to the
* parent clock (which may propagate again if the parent clock
* also sets this flag). The requested rate of the parent is
* passed back from the callback in the second 'unsigned long *'
* argument. Note that it is up to the hardware clock's set_rate
* implementation to insure that clocks do not run out of spec
* when propgating the call to set_rate up to the parent. One way
* to do this is to gate the clock (via clk_disable and/or
* clk_unprepare) before calling clk_set_rate, then ungating it
* afterward. If your clock also has the CLK_GATE_SET_RATE flag
* set then this will insure safety. Returns 0 on success,
* -EERROR otherwise.
*
* The clk_enable/clk_disable and clk_prepare/clk_unprepare pairs allow
* implementations to split any work between atomic (enable) and sleepable
* (prepare) contexts. If enabling a clock requires code that might sleep,
* this must be done in clk_prepare. Clock enable code that will never be
* called in a sleepable context may be implement in clk_enable.
*
* Typically, drivers will call clk_prepare when a clock may be needed later
* (eg. when a device is opened), and clk_enable when the clock is actually
* required (eg. from an interrupt). Note that clk_prepare MUST have been
* called before clk_enable.
*/
struct clk_ops {
int (*prepare)(struct clk_hw *hw);
void (*unprepare)(struct clk_hw *hw);
int (*enable)(struct clk_hw *hw);
void (*disable)(struct clk_hw *hw);
int (*is_enabled)(struct clk_hw *hw);
unsigned long (*recalc_rate)(struct clk_hw *hw,
unsigned long parent_rate);
long (*round_rate)(struct clk_hw *hw, unsigned long,
unsigned long *);
int (*set_parent)(struct clk_hw *hw, u8 index);
u8 (*get_parent)(struct clk_hw *hw);
int (*set_rate)(struct clk_hw *hw, unsigned long);
void (*init)(struct clk_hw *hw);
};
/*
* DOC: Basic clock implementations common to many platforms
*
* Each basic clock hardware type is comprised of a structure describing the
* clock hardware, implementations of the relevant callbacks in struct clk_ops,
* unique flags for that hardware type, a registration function and an
* alternative macro for static initialization
*/
/**
* struct clk_fixed_rate - fixed-rate clock
* @hw: handle between common and hardware-specific interfaces
* @fixed_rate: constant frequency of clock
*/
struct clk_fixed_rate {
struct clk_hw hw;
unsigned long fixed_rate;
u8 flags;
};
struct clk *clk_register_fixed_rate(struct device *dev, const char *name,
const char *parent_name, unsigned long flags,
unsigned long fixed_rate);
/**
* struct clk_gate - gating clock
*
* @hw: handle between common and hardware-specific interfaces
* @reg: register controlling gate
* @bit_idx: single bit controlling gate
* @flags: hardware-specific flags
* @lock: register lock
*
* Clock which can gate its output. Implements .enable & .disable
*
* Flags:
* CLK_GATE_SET_DISABLE - by default this clock sets the bit at bit_idx to
* enable the clock. Setting this flag does the opposite: setting the bit
* disable the clock and clearing it enables the clock
*/
struct clk_gate {
struct clk_hw hw;
void __iomem *reg;
u8 bit_idx;
u8 flags;
spinlock_t *lock;
char *parent[1];
};
#define CLK_GATE_SET_TO_DISABLE BIT(0)
struct clk *clk_register_gate(struct device *dev, const char *name,
const char *parent_name, unsigned long flags,
void __iomem *reg, u8 bit_idx,
u8 clk_gate_flags, spinlock_t *lock);
/**
* struct clk_divider - adjustable divider clock
*
* @hw: handle between common and hardware-specific interfaces
* @reg: register containing the divider
* @shift: shift to the divider bit field
* @width: width of the divider bit field
* @lock: register lock
*
* Clock with an adjustable divider affecting its output frequency. Implements
* .recalc_rate, .set_rate and .round_rate
*
* Flags:
* CLK_DIVIDER_ONE_BASED - by default the divisor is the value read from the
* register plus one. If CLK_DIVIDER_ONE_BASED is set then the divider is
* the raw value read from the register, with the value of zero considered
* invalid
* CLK_DIVIDER_POWER_OF_TWO - clock divisor is 2 raised to the value read from
* the hardware register
*/
struct clk_divider {
struct clk_hw hw;
void __iomem *reg;
u8 shift;
u8 width;
u8 flags;
spinlock_t *lock;
char *parent[1];
};
#define CLK_DIVIDER_ONE_BASED BIT(0)
#define CLK_DIVIDER_POWER_OF_TWO BIT(1)
struct clk *clk_register_divider(struct device *dev, const char *name,
const char *parent_name, unsigned long flags,
void __iomem *reg, u8 shift, u8 width,
u8 clk_divider_flags, spinlock_t *lock);
/**
* struct clk_mux - multiplexer clock
*
* @hw: handle between common and hardware-specific interfaces
* @reg: register controlling multiplexer
* @shift: shift to multiplexer bit field
* @width: width of mutliplexer bit field
* @num_clks: number of parent clocks
* @lock: register lock
*
* Clock with multiple selectable parents. Implements .get_parent, .set_parent
* and .recalc_rate
*
* Flags:
* CLK_MUX_INDEX_ONE - register index starts at 1, not 0
* CLK_MUX_INDEX_BITWISE - register index is a single bit (power of two)
*/
struct clk_mux {
struct clk_hw hw;
void __iomem *reg;
u8 shift;
u8 width;
u8 flags;
spinlock_t *lock;
};
#define CLK_MUX_INDEX_ONE BIT(0)
#define CLK_MUX_INDEX_BIT BIT(1)
struct clk *clk_register_mux(struct device *dev, const char *name,
char **parent_names, u8 num_parents, unsigned long flags,
void __iomem *reg, u8 shift, u8 width,
u8 clk_mux_flags, spinlock_t *lock);
/**
* clk_register - allocate a new clock, register it and return an opaque cookie
* @dev: device that is registering this clock
* @name: clock name
* @ops: operations this clock supports
* @hw: link to hardware-specific clock data
* @parent_names: array of string names for all possible parents
* @num_parents: number of possible parents
* @flags: framework-level hints and quirks
*
* clk_register is the primary interface for populating the clock tree with new
* clock nodes. It returns a pointer to the newly allocated struct clk which
* cannot be dereferenced by driver code but may be used in conjuction with the
* rest of the clock API.
*/
struct clk *clk_register(struct device *dev, const char *name,
const struct clk_ops *ops, struct clk_hw *hw,
char **parent_names, u8 num_parents, unsigned long flags);
/* helper functions */
const char *__clk_get_name(struct clk *clk);
struct clk_hw *__clk_get_hw(struct clk *clk);
u8 __clk_get_num_parents(struct clk *clk);
struct clk *__clk_get_parent(struct clk *clk);
inline int __clk_get_enable_count(struct clk *clk);
inline int __clk_get_prepare_count(struct clk *clk);
unsigned long __clk_get_rate(struct clk *clk);
unsigned long __clk_get_flags(struct clk *clk);
int __clk_is_enabled(struct clk *clk);
struct clk *__clk_lookup(const char *name);
/*
* FIXME clock api without lock protection
*/
int __clk_prepare(struct clk *clk);
void __clk_unprepare(struct clk *clk);
void __clk_reparent(struct clk *clk, struct clk *new_parent);
unsigned long __clk_round_rate(struct clk *clk, unsigned long rate);
#endif /* CONFIG_COMMON_CLK */
#endif /* CLK_PROVIDER_H */
