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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
CLOCK_CONTROL_ASYNC_DATA_DEFINE(name, cb, user_data)

Define and initialize clock_control async data.

Parameters
  • name: Name of the data.

  • cb: Callback.

  • user_data: User data

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_cb_t)(struct device *dev, clock_control_subsys_t subsys, void *user_data)

Callback called on clock started.

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

  • subsys: Opaque data representing the clock.

  • user_data: User data.

typedef int (*clock_control)(struct device *dev, clock_control_subsys_t sys)
typedef int (*clock_control_get)(struct device *dev, clock_control_subsys_t sys, u32_t *rate)
typedef int (*clock_control_async_on_fn)(struct device *dev, clock_control_subsys_t sys, struct clock_control_async_data *data)
typedef enum clock_control_status (*clock_control_get_status_fn)(struct device *dev, clock_control_subsys_t sys)

Enums

enum clock_control_status

Current clock status.

Values:

CLOCK_CONTROL_STATUS_STARTING
CLOCK_CONTROL_STATUS_OFF
CLOCK_CONTROL_STATUS_ON
CLOCK_CONTROL_STATUS_UNKNOWN

Functions

static int clock_control_on(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.

Return

0 on success, negative errno on failure.

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

  • sys: Opaque data representing the clock.

static int clock_control_off(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.

Return

0 on success, negative errno on failure.

Parameters
  • dev: Device structure whose driver controls the clock

  • sys: Opaque data representing the clock

static int clock_control_async_on(struct device *dev, clock_control_subsys_t sys, struct clock_control_async_data *data)

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

Function is non-blocking and can be called from any context. When clock is already running user callback will be called from the context of the function call else it is called from other context (e.g. clock interrupt).

Parameters
  • dev: Device.

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

  • data: Data structure containing a callback that is called when action is performed. Structure content must be valid until clock is started and user callback is called. Can be NULL.

Return Value
  • 0: if clock is started or already running.

  • -EBUSY: if same request already scheduled and not yet completed.

  • -ENOTSUP: if not supported.

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

Get clock status.

Return

Status.

Parameters
  • dev: Device.

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

static int clock_control_get_rate(struct device *dev, clock_control_subsys_t sys, u32_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

  • [out] rate: Subsystem clock rate

struct clock_control_async_data
#include <clock_control.h>

Clock control data used for asynchronous clock enabling.

Parameters
  • node: Used internally for linking asynchronous requests.

  • cb: Callback called when clock is started.

  • user_data: User data passed as an argument in the callback.