/**
* 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.
*
* @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.
* 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
* 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.
* Returns 0 on success, -EERROR otherwise.
*
* @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_rate: Change the rate of this clock. The requested rate is specified
* by the second argument, which should typically be the return
* of .round_rate call. The third argument gives the parent rate
* which is likely helpful for most .set_rate implementation.
* Returns 0 on success, -EERROR otherwise.
*
* @set_rate_and_parent: Change the rate and the parent of this clock. The
* requested rate is specified by the second argument, which
* should typically be the return of .round_rate call. The
* third argument gives the parent rate which is likely helpful
* for most .set_rate_and_parent implementation. The fourth
* argument gives the parent index. This callback is optional (and
* unnecessary) for clocks with 0 or 1 parents as well as
* for clocks that can tolerate switching the rate and the parent
* separately via calls to .set_parent and .set_rate.
* Returns 0 on success, -EERROR otherwise.
*
* @recalc_accuracy: Recalculate the accuracy of this clock. The clock accuracy
* is expressed in ppb (parts per billion). The parent accuracy is
* an input parameter.
* Returns the calculated accuracy. Optional - if this op is not
* set then clock accuracy will be initialized to parent accuracy
* or 0 (perfect clock) if clock has no parent.
*
* @get_phase: Queries the hardware to get the current phase of a clock.
* Returned values are 0-359 degrees on success, negative
* error codes on failure.
*
* @set_phase: Shift the phase this clock signal in degrees specified
* by the second argument. Valid values for degrees are
* 0-359. Return 0 on success, otherwise -EERROR.
*
* @init: Perform platform-specific initialization magic.
* This is not not used by any of the basic clock types.
* Please consider other ways of solving initialization problems
* before using this callback, as its use is discouraged.
*
* @debug_init: Set up type-specific debugfs entries for this clock. This
* is called once, after the debugfs directory entry for this
* clock has been created. The dentry pointer representing that
* directory is provided as an argument. Called with
* prepare_lock held. 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 implemented 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 (*is_prepared)(struct clk_hw *hw);
void (*unprepare_unused)(struct clk_hw *hw);
int (*enable)(struct clk_hw *hw);
void (*disable)(struct clk_hw *hw);
int (*is_enabled)(struct clk_hw *hw);
void (*disable_unused)(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 rate,
unsigned long *parent_rate);
int (*determine_rate)(struct clk_hw *hw,
struct clk_rate_request *req);
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 rate,
unsigned long parent_rate);
int (*set_rate_and_parent)(struct clk_hw *hw,
unsigned long rate,
unsigned long parent_rate, u8 index);
unsigned long (*recalc_accuracy)(struct clk_hw *hw,
unsigned long parent_accuracy);
int (*get_phase)(struct clk_hw *hw);
int (*set_phase)(struct clk_hw *hw, int degrees);
void (*init)(struct clk_hw *hw);
int (*debug_init)(struct clk_hw *hw, struct dentry *dentry);
};
