Clock Control

Overview

The clock control API provides access to clocks in the system, including the ability to turn them on and off.

Configuration Options

Related configuration options:

API Reference

group clock_control_interface

Clock Control Interface.

Defines

CLOCK_CONTROL_SUBSYS_ALL

Typedefs

typedef void *clock_control_subsys_t

clock_control_subsys_t is a type to identify a clock controller sub-system. Such data pointed is opaque and relevant only to the clock controller driver instance being used.

typedef void *clock_control_subsys_rate_t

clock_control_subsys_rate_t is a type to identify a clock controller sub-system rate. Such data pointed is opaque and relevant only to set the clock controller rate of the driver instance being used.

typedef void (*clock_control_cb_t)(const struct device *dev, clock_control_subsys_t subsys, void *user_data)

Callback called on clock started.

Param dev

Device structure whose driver controls the clock.

Param subsys

Opaque data representing the clock.

Param user_data

User data.

typedef int (*clock_control)(const struct device *dev, clock_control_subsys_t sys)
typedef int (*clock_control_get)(const struct device *dev, clock_control_subsys_t sys, uint32_t *rate)
typedef int (*clock_control_async_on_fn)(const struct device *dev, clock_control_subsys_t sys, clock_control_cb_t cb, void *user_data)
typedef enum clock_control_status (*clock_control_get_status_fn)(const struct device *dev, clock_control_subsys_t sys)
typedef int (*clock_control_set)(const struct device *dev, clock_control_subsys_t sys, clock_control_subsys_rate_t rate)

Enums

enum clock_control_status

Current clock status.

Values:

enumerator CLOCK_CONTROL_STATUS_STARTING
enumerator CLOCK_CONTROL_STATUS_OFF
enumerator CLOCK_CONTROL_STATUS_ON
enumerator CLOCK_CONTROL_STATUS_UNAVAILABLE
enumerator CLOCK_CONTROL_STATUS_UNKNOWN

Functions

static inline int clock_control_on(const struct device *dev, clock_control_subsys_t sys)

Enable a clock controlled by the device.

On success, the clock is enabled and ready when this function returns. This function may sleep, and thus can only be called from thread context.

Use clock_control_async_on() for non-blocking operation.

Parameters
  • dev – Device structure whose driver controls the clock.

  • sys – Opaque data representing the clock.

Returns

0 on success, negative errno on failure.

static inline int clock_control_off(const struct device *dev, clock_control_subsys_t sys)

Disable a clock controlled by the device.

This function is non-blocking and can be called from any context. On success, the clock is disabled when this function returns.

Parameters
  • dev – Device structure whose driver controls the clock

  • sys – Opaque data representing the clock

Returns

0 on success, negative errno on failure.

static inline int clock_control_async_on(const struct device *dev, clock_control_subsys_t sys, clock_control_cb_t cb, void *user_data)

Request clock to start with notification when clock has been started.

Function is non-blocking and can be called from any context. User callback is called when clock is started.

Parameters
  • dev – Device.

  • sys – A pointer to an opaque data representing the sub-system.

  • cb – Callback.

  • user_data – User context passed to the callback.

Return values
  • 0 – if start is successfully initiated.

  • -EALREADY – if clock was already started and is starting or running.

  • -ENOTSUP – If the requested mode of operation is not supported.

  • -ENOSYS – if the interface is not implemented.

  • other – negative errno on vendor specific error.

static inline enum clock_control_status clock_control_get_status(const struct device *dev, clock_control_subsys_t sys)

Get clock status.

Parameters
  • dev – Device.

  • sys – A pointer to an opaque data representing the sub-system.

Returns

Status.

static inline int clock_control_get_rate(const struct device *dev, clock_control_subsys_t sys, uint32_t *rate)

Obtain the clock rate of given sub-system.

Parameters
  • dev – Pointer to the device structure for the clock controller driver instance

  • sys – A pointer to an opaque data representing the sub-system

  • rate[out] Subsystem clock rate

static inline int clock_control_set_rate(const struct device *dev, clock_control_subsys_t sys, clock_control_subsys_rate_t rate)

Set the rate of the clock controlled by the device.

On success, the new clock rate is set and ready when this function returns. This function may sleep, and thus can only be called from thread context.

Parameters
  • dev – Device structure whose driver controls the clock.

  • sys – Opaque data representing the clock.

  • rate – Opaque data representing the clock rate to be used.

Return values
  • -EALREADY – if clock was already in the given rate.

  • -ENOTSUP – If the requested mode of operation is not supported.

  • -ENOSYS – if the interface is not implemented.

  • other – negative errno on vendor specific error.

struct clock_control_driver_api
#include <clock_control.h>