Counter

Interfaces for counters. More...

Files
file	counter.h
	Main header file for counter driver API.

Data Structures
struct	counter_alarm_cfg
	Alarm callback structure. More...
struct	counter_top_cfg
	Top value configuration structure. More...
struct	counter_config_info
	Structure with generic counter features. More...
struct	counter_alarm_cfg_64
	Alarm callback structure. More...
struct	counter_top_cfg_64
	Top value configuration structure. More...
struct	counter_driver_api

Typedefs
typedef void(*	counter_alarm_callback_t) (const struct device *dev, uint8_t chan_id, uint32_t ticks, void *user_data)
	Alarm callback.
typedef void(*	counter_top_callback_t) (const struct device *dev, void *user_data)
	Callback called when counter turns around.
typedef void(*	counter_alarm_callback_64_t) (const struct device *dev, uint8_t chan_id, uint64_t ticks, void *user_data)
	Alarm callback.
typedef int(*	counter_api_start) (const struct device *dev)
typedef int(*	counter_api_stop) (const struct device *dev)
typedef int(*	counter_api_get_value) (const struct device *dev, uint32_t *ticks)
typedef int(*	counter_api_reset) (const struct device *dev)
typedef int(*	counter_api_set_value) (const struct device *dev, uint32_t ticks)
typedef int(*	counter_api_set_alarm) (const struct device *dev, uint8_t chan_id, const struct counter_alarm_cfg *alarm_cfg)
typedef int(*	counter_api_cancel_alarm) (const struct device *dev, uint8_t chan_id)
typedef int(*	counter_api_set_top_value) (const struct device *dev, const struct counter_top_cfg *cfg)
typedef uint32_t(*	counter_api_get_pending_int) (const struct device *dev)
typedef uint32_t(*	counter_api_get_top_value) (const struct device *dev)
typedef uint32_t(*	counter_api_get_guard_period) (const struct device *dev, uint32_t flags)
typedef int(*	counter_api_set_guard_period) (const struct device *dev, uint32_t ticks, uint32_t flags)
typedef uint32_t(*	counter_api_get_freq) (const struct device *dev)
typedef uint64_t(*	counter_api_get_freq_64) (const struct device *dev)
typedef int(*	counter_api_get_value_64) (const struct device *dev, uint64_t *ticks)
typedef int(*	counter_api_set_value_64) (const struct device *dev, uint64_t ticks)
typedef int(*	counter_api_set_alarm_64) (const struct device *dev, uint8_t chan_id, const struct counter_alarm_cfg_64 *alarm_cfg)
typedef uint64_t(*	counter_api_get_guard_period_64) (const struct device *dev, uint32_t flags)
typedef int(*	counter_api_set_guard_period_64) (const struct device *dev, uint64_t ticks, uint32_t flags)
typedef uint64_t(*	counter_api_get_top_value_64) (const struct device *dev)
typedef int(*	counter_api_set_top_value_64) (const struct device *dev, const struct counter_top_cfg_64 *cfg)

Functions
bool	counter_is_counting_up (const struct device *dev)
	Function to check if counter is counting up.
uint8_t	counter_get_num_of_channels (const struct device *dev)
	Function to get number of alarm channels.
uint32_t	counter_get_frequency (const struct device *dev)
uint64_t	counter_get_frequency_64 (const struct device *dev)
	Function to get counter frequency in 64bits.
uint32_t	counter_us_to_ticks (const struct device *dev, uint64_t us)
	Function to convert microseconds to ticks.
uint64_t	counter_us_to_ticks_64 (const struct device *dev, uint64_t us)
	Function to convert microseconds to ticks with 64 bits.
uint64_t	counter_ticks_to_us (const struct device *dev, uint32_t ticks)
	Function to convert ticks to microseconds.
uint64_t	counter_ticks_to_us_64 (const struct device *dev, uint64_t ticks)
	Function to convert ticks with 64 bits to microseconds.
uint32_t	counter_ns_to_ticks (const struct device *dev, uint64_t ns)
	Function to convert nanoseconds to ticks.
uint64_t	counter_ns_to_ticks_64 (const struct device *dev, uint64_t ns)
	Function to convert nanoseconds to ticks with 64 bits.
uint64_t	counter_ticks_to_ns (const struct device *dev, uint32_t ticks)
	Function to convert ticks to nanoseconds.
uint64_t	counter_ticks_to_ns_64 (const struct device *dev, uint64_t ticks)
	Function to convert ticks with 64 bits to nanoseconds.
uint32_t	counter_get_max_top_value (const struct device *dev)
	Function to retrieve maximum top value that can be set.
int	counter_start (const struct device *dev)
	Start counter device in free running mode.
int	counter_stop (const struct device *dev)
	Stop counter device.
int	counter_get_value (const struct device *dev, uint32_t *ticks)
	Get current counter value.
int	counter_reset (const struct device *dev)
	Reset the counter to the initial value.
int	counter_set_value (const struct device *dev, uint32_t ticks)
	Set current counter value.
int	counter_set_channel_alarm (const struct device *dev, uint8_t chan_id, const struct counter_alarm_cfg *alarm_cfg)
	Set a single shot alarm on a channel.
int	counter_cancel_channel_alarm (const struct device *dev, uint8_t chan_id)
	Cancel an alarm on a channel.
int	counter_set_top_value (const struct device *dev, const struct counter_top_cfg *cfg)
	Set counter top value.
int	counter_get_pending_int (const struct device *dev)
	Function to get pending interrupts.
uint32_t	counter_get_top_value (const struct device *dev)
	Function to retrieve current top value.
int	counter_set_guard_period (const struct device *dev, uint32_t ticks, uint32_t flags)
	Set guard period in counter ticks.
uint32_t	counter_get_guard_period (const struct device *dev, uint32_t flags)
	Return guard period.
uint64_t	counter_get_max_top_value_64 (const struct device *dev)
	Function to retrieve maximum top value that can be set for 64 bits.
int	counter_set_top_value_64 (const struct device *dev, const struct counter_top_cfg_64 *cfg)
	Set counter top value for 64 bits.
int	counter_set_channel_alarm_64 (const struct device *dev, uint8_t chan_id, const struct counter_alarm_cfg_64 *alarm_cfg)
	Set a single shot alarm on a channel for 64 bits.
uint64_t	counter_get_top_value_64 (const struct device *dev)
	Function to retrieve current top value for 64 bits.
int	counter_set_guard_period_64 (const struct device *dev, uint64_t ticks, uint32_t flags)
	Set guard period in counter ticks for 64 bits.
uint64_t	counter_get_guard_period_64 (const struct device *dev, uint32_t flags)
	Return guard period for 64 bits.
int	counter_get_value_64 (const struct device *dev, uint64_t *ticks)
	Get current counter 64-bit value.
int	counter_set_value_64 (const struct device *dev, uint64_t ticks)
	Set current counter 64-bit value.

Counter device capabilities
#define	COUNTER_CONFIG_INFO_COUNT_UP   BIT(0)
	Counter count up flag.

Flags used by counter_top_cfg.
#define	COUNTER_TOP_CFG_DONT_RESET   BIT(0)
	Flag preventing counter reset when top value is changed.
#define	COUNTER_TOP_CFG_RESET_WHEN_LATE   BIT(1)
	Flag instructing counter to reset itself if changing top value results in counter going out of new top value bound.

Alarm configuration flags
Used in alarm configuration structure (counter_alarm_cfg).
#define	COUNTER_ALARM_CFG_ABSOLUTE   BIT(0)
	Counter alarm absolute value flag.
#define	COUNTER_ALARM_CFG_EXPIRE_WHEN_LATE   BIT(1)
	Alarm flag enabling immediate expiration when driver detects that absolute alarm was set too late.

Counter guard period flags
Used by counter_set_guard_period and counter_get_guard_period.
#define	COUNTER_GUARD_PERIOD_LATE_TO_SET   BIT(0)
	Identifies guard period needed for detection of late setting of absolute alarm (see counter_set_channel_alarm).

Detailed Description

Interfaces for counters.

Since

1.14

Version

1.0.0

Macro Definition Documentation

COUNTER_ALARM_CFG_ABSOLUTE

#define COUNTER_ALARM_CFG_ABSOLUTE   BIT(0)

#include <zephyr/drivers/counter.h>

Counter alarm absolute value flag.

Ticks relation to counter value. If set ticks are treated as absolute value, else it is relative to the counter reading performed during the call.

COUNTER_ALARM_CFG_EXPIRE_WHEN_LATE

#define COUNTER_ALARM_CFG_EXPIRE_WHEN_LATE   BIT(1)

#include <zephyr/drivers/counter.h>

Alarm flag enabling immediate expiration when driver detects that absolute alarm was set too late.

Alarm callback must be called from the same context as if it was set on time.

COUNTER_CONFIG_INFO_COUNT_UP

#define COUNTER_CONFIG_INFO_COUNT_UP   BIT(0)

#include <zephyr/drivers/counter.h>

Counter count up flag.

COUNTER_GUARD_PERIOD_LATE_TO_SET

#define COUNTER_GUARD_PERIOD_LATE_TO_SET   BIT(0)

#include <zephyr/drivers/counter.h>

Identifies guard period needed for detection of late setting of absolute alarm (see counter_set_channel_alarm).

COUNTER_TOP_CFG_DONT_RESET

#define COUNTER_TOP_CFG_DONT_RESET   BIT(0)

#include <zephyr/drivers/counter.h>

Flag preventing counter reset when top value is changed.

If flags is set then counter is free running while top value is updated, otherwise counter is reset (see counter_set_top_value()).

COUNTER_TOP_CFG_RESET_WHEN_LATE

#define COUNTER_TOP_CFG_RESET_WHEN_LATE   BIT(1)

#include <zephyr/drivers/counter.h>

Flag instructing counter to reset itself if changing top value results in counter going out of new top value bound.

See COUNTER_TOP_CFG_DONT_RESET.

Typedef Documentation

counter_alarm_callback_64_t

typedef void(* counter_alarm_callback_64_t) (const struct device *dev, uint8_t chan_id, uint64_t ticks, void *user_data)

#include <zephyr/drivers/counter.h>

Alarm callback.

Parameters

dev	Pointer to the device structure for the driver instance.
chan_id	Channel ID.
ticks	Counter value that triggered the alarm.
user_data	User data.

counter_alarm_callback_t

typedef void(* counter_alarm_callback_t) (const struct device *dev, uint8_t chan_id, uint32_t ticks, void *user_data)

#include <zephyr/drivers/counter.h>

Alarm callback.

Parameters

dev	Pointer to the device structure for the driver instance.
chan_id	Channel ID.
ticks	Counter value that triggered the alarm.
user_data	User data.

counter_api_cancel_alarm

typedef int(* counter_api_cancel_alarm) (const struct device *dev, uint8_t chan_id)

#include <zephyr/drivers/counter.h>

counter_api_get_freq

typedef uint32_t(* counter_api_get_freq) (const struct device *dev)

#include <zephyr/drivers/counter.h>

counter_api_get_freq_64

typedef uint64_t(* counter_api_get_freq_64) (const struct device *dev)

#include <zephyr/drivers/counter.h>

counter_api_get_guard_period

typedef uint32_t(* counter_api_get_guard_period) (const struct device *dev, uint32_t flags)

#include <zephyr/drivers/counter.h>

counter_api_get_guard_period_64

typedef uint64_t(* counter_api_get_guard_period_64) (const struct device *dev, uint32_t flags)

#include <zephyr/drivers/counter.h>

counter_api_get_pending_int

typedef uint32_t(* counter_api_get_pending_int) (const struct device *dev)

#include <zephyr/drivers/counter.h>

counter_api_get_top_value

typedef uint32_t(* counter_api_get_top_value) (const struct device *dev)

#include <zephyr/drivers/counter.h>

counter_api_get_top_value_64

typedef uint64_t(* counter_api_get_top_value_64) (const struct device *dev)

#include <zephyr/drivers/counter.h>

counter_api_get_value

typedef int(* counter_api_get_value) (const struct device *dev, uint32_t *ticks)

#include <zephyr/drivers/counter.h>

counter_api_get_value_64

typedef int(* counter_api_get_value_64) (const struct device *dev, uint64_t *ticks)

#include <zephyr/drivers/counter.h>

counter_api_reset

typedef int(* counter_api_reset) (const struct device *dev)

#include <zephyr/drivers/counter.h>

counter_api_set_alarm

typedef int(* counter_api_set_alarm) (const struct device *dev, uint8_t chan_id, const struct counter_alarm_cfg *alarm_cfg)

#include <zephyr/drivers/counter.h>

counter_api_set_alarm_64

typedef int(* counter_api_set_alarm_64) (const struct device *dev, uint8_t chan_id, const struct counter_alarm_cfg_64 *alarm_cfg)

#include <zephyr/drivers/counter.h>

counter_api_set_guard_period

typedef int(* counter_api_set_guard_period) (const struct device *dev, uint32_t ticks, uint32_t flags)

#include <zephyr/drivers/counter.h>

counter_api_set_guard_period_64

typedef int(* counter_api_set_guard_period_64) (const struct device *dev, uint64_t ticks, uint32_t flags)

#include <zephyr/drivers/counter.h>

counter_api_set_top_value

typedef int(* counter_api_set_top_value) (const struct device *dev, const struct counter_top_cfg *cfg)

#include <zephyr/drivers/counter.h>

counter_api_set_top_value_64

typedef int(* counter_api_set_top_value_64) (const struct device *dev, const struct counter_top_cfg_64 *cfg)

#include <zephyr/drivers/counter.h>

counter_api_set_value

typedef int(* counter_api_set_value) (const struct device *dev, uint32_t ticks)

#include <zephyr/drivers/counter.h>

counter_api_set_value_64

typedef int(* counter_api_set_value_64) (const struct device *dev, uint64_t ticks)

#include <zephyr/drivers/counter.h>

counter_api_start

typedef int(* counter_api_start) (const struct device *dev)

#include <zephyr/drivers/counter.h>

counter_api_stop

typedef int(* counter_api_stop) (const struct device *dev)

#include <zephyr/drivers/counter.h>

counter_top_callback_t

typedef void(* counter_top_callback_t) (const struct device *dev, void *user_data)

#include <zephyr/drivers/counter.h>

Callback called when counter turns around.

Parameters

dev	Pointer to the device structure for the driver instance.
user_data	User data provided in counter_set_top_value.

Function Documentation

counter_cancel_channel_alarm()

int counter_cancel_channel_alarm	(	const struct device *	dev,
		uint8_t	chan_id )

#include <zephyr/drivers/counter.h>

Cancel an alarm on a channel.

Note

API is not thread safe.

Parameters

dev	Pointer to the device structure for the driver instance.
chan_id	Channel ID.

Return values

0	If successful.
-ENOTSUP	if request is not supported or the counter was not started yet.

counter_get_frequency()

uint32_t counter_get_frequency

(

const struct device *

dev

)

#include <zephyr/drivers/counter.h>

counter_get_frequency_64()

uint64_t counter_get_frequency_64

(

const struct device *

dev

)

#include <zephyr/drivers/counter.h>

Function to get counter frequency in 64bits.

Parameters

[in]

dev

Pointer to the device structure for the driver instance.

Returns

Frequency of the counter in Hz, or zero if the counter does not have a fixed frequency.

counter_get_guard_period()

uint32_t counter_get_guard_period	(	const struct device *	dev,
		uint32_t	flags )

#include <zephyr/drivers/counter.h>

Return guard period.

See also

counter_set_guard_period.

Parameters

dev	Pointer to the device structure for the driver instance.
flags	See COUNTER_GUARD_PERIOD_FLAGS.

Returns

Guard period given in counter ticks or 0 if function or flags are not supported.

counter_get_guard_period_64()

uint64_t counter_get_guard_period_64	(	const struct device *	dev,
		uint32_t	flags )

#include <zephyr/drivers/counter.h>

Return guard period for 64 bits.

See also

counter_set_guard_period_64.

Parameters

dev	Pointer to the device structure for the driver instance.
flags	See COUNTER_GUARD_PERIOD_FLAGS.

Returns

Guard period given in counter ticks or 0 if function or flags are not supported.

counter_get_max_top_value()

uint32_t counter_get_max_top_value

(

const struct device *

dev

)

#include <zephyr/drivers/counter.h>

Function to retrieve maximum top value that can be set.

Parameters

[in]

dev

Pointer to the device structure for the driver instance.

Warning

With CONFIG_COUNTER_64BITS_TICKS enabled this function returns only the lower 32 bits of the max top value. Use counter_get_max_top_value_64() to get the full 64 bit value if it is expected to exceed 32 bits.

Returns

Max top value.

counter_get_max_top_value_64()

uint64_t counter_get_max_top_value_64

(

const struct device *

dev

)

#include <zephyr/drivers/counter.h>

Function to retrieve maximum top value that can be set for 64 bits.

Parameters

[in]

dev

Pointer to the device structure for the driver instance.

Returns

Max top value in 64 bits.

counter_get_num_of_channels()

uint8_t counter_get_num_of_channels

(

const struct device *

dev

)

#include <zephyr/drivers/counter.h>

Function to get number of alarm channels.

Parameters

[in]

dev

Pointer to the device structure for the driver instance.

Returns

Number of alarm channels.

counter_get_pending_int()

int counter_get_pending_int

(

const struct device *

dev

)

#include <zephyr/drivers/counter.h>

Function to get pending interrupts.

The purpose of this function is to return the interrupt status register for the device. This is especially useful when waking up from low power states to check the wake up source.

Parameters

dev	Pointer to the device structure for the driver instance.

Return values

1	if any counter interrupt is pending.
0	if no counter interrupt is pending.

counter_get_top_value()

uint32_t counter_get_top_value

(

const struct device *

dev

)

#include <zephyr/drivers/counter.h>

Function to retrieve current top value.

Parameters

[in]

dev

Pointer to the device structure for the driver instance.

Returns

Top value.

counter_get_top_value_64()

uint64_t counter_get_top_value_64

(

const struct device *

dev

)

#include <zephyr/drivers/counter.h>

Function to retrieve current top value for 64 bits.

Parameters

[in]

dev

Pointer to the device structure for the driver instance.

Returns

Top value in 64 bits.

counter_get_value()

int counter_get_value	(	const struct device *	dev,
		uint32_t *	ticks )

#include <zephyr/drivers/counter.h>

Get current counter value.

Parameters

dev	Pointer to the device structure for the driver instance.
ticks	Pointer to where to store the current counter value

Return values

0	If successful.
<0	Negative error code on failure getting the counter value

counter_get_value_64()

int counter_get_value_64	(	const struct device *	dev,
		uint64_t *	ticks )

#include <zephyr/drivers/counter.h>

Get current counter 64-bit value.

Parameters

dev	Pointer to the device structure for the driver instance.
ticks	Pointer to where to store the current counter value in 64 bits.

Return values

0	If successful.
<0	Negative error code on failure getting the counter value

counter_is_counting_up()

bool counter_is_counting_up

(

const struct device *

dev

)

#include <zephyr/drivers/counter.h>

Function to check if counter is counting up.

Parameters

[in]

dev

Pointer to the device structure for the driver instance.

Return values

true	if counter is counting up.
false	if counter is counting down.

counter_ns_to_ticks()

uint32_t counter_ns_to_ticks	(	const struct device *	dev,
		uint64_t	ns )

#include <zephyr/drivers/counter.h>

Function to convert nanoseconds to ticks.

Parameters

[in]	dev	Pointer to the device structure for the driver instance.
[in]	ns	Nanoseconds.

Returns

Converted ticks. Ticks will be saturated if exceed 32 bits.

counter_ns_to_ticks_64()

uint64_t counter_ns_to_ticks_64	(	const struct device *	dev,
		uint64_t	ns )

#include <zephyr/drivers/counter.h>

Function to convert nanoseconds to ticks with 64 bits.

Parameters

[in]	dev	Pointer to the device structure for the driver instance.
[in]	ns	Nanoseconds.

Returns

Converted ticks as a uint64_t.

counter_reset()

int counter_reset

(

const struct device *

dev

)

#include <zephyr/drivers/counter.h>

Reset the counter to the initial value.

Parameters

dev	Pointer to the device structure for the driver instance.

Return values

0	If successful.
-errno	Negative error code on failure resetting the counter value.

counter_set_channel_alarm()

int counter_set_channel_alarm	(	const struct device *	dev,
		uint8_t	chan_id,
		const struct counter_alarm_cfg *	alarm_cfg )

#include <zephyr/drivers/counter.h>

Set a single shot alarm on a channel.

After expiration alarm can be set again, disabling is not needed. When alarm expiration handler is called, channel is considered available and can be set again in that context.

Note

API is not thread safe.

Parameters

dev	Pointer to the device structure for the driver instance.
chan_id	Channel ID.
alarm_cfg	Alarm configuration.

Return values

0	If successful.
-ENOTSUP	if request is not supported (device does not support interrupts or requested channel).
-EINVAL	if alarm settings are invalid.
-ETIME	if absolute alarm was set too late.
-EBUSY	if alarm is already active.

counter_set_channel_alarm_64()

int counter_set_channel_alarm_64	(	const struct device *	dev,
		uint8_t	chan_id,
		const struct counter_alarm_cfg_64 *	alarm_cfg )

#include <zephyr/drivers/counter.h>

Set a single shot alarm on a channel for 64 bits.

After expiration alarm can be set again, disabling is not needed. When alarm expiration handler is called, channel is considered available and can be set again in that context.

Note

API is not thread safe.

Parameters

dev	Pointer to the device structure for the driver instance.
chan_id	Channel ID.
alarm_cfg	Alarm configuration.

Return values

0	If successful.
-ENOTSUP	if request is not supported (device does not support interrupts or requested channel).
-EINVAL	if alarm settings are invalid.
-ETIME	if absolute alarm was set too late.
-EBUSY	if alarm is already active.

counter_set_guard_period()

int counter_set_guard_period	(	const struct device *	dev,
		uint32_t	ticks,
		uint32_t	flags )

#include <zephyr/drivers/counter.h>

Set guard period in counter ticks.

When setting an absolute alarm value close to the current counter value there is a risk that the counter will have counted past the given absolute value before the driver manages to activate the alarm. If this would go unnoticed then the alarm would only expire after the timer has wrapped and reached the given absolute value again after a full timer period. This could take a long time in case of a 32 bit timer. Setting a sufficiently large guard period will help the driver detect unambiguously whether it is late or not.

The guard period should be as many counter ticks as the driver will need at most to actually activate the alarm after the driver API has been called. If the driver finds that the counter has just passed beyond the given absolute tick value but is still close enough to fall within the guard period, it will assume that it is "late", i.e. that the intended expiry time has already passed. Depending on the COUNTER_ALARM_CFG_EXPIRE_WHEN_LATE flag the driver will either ignore the alarm or expire it immediately in such a case.

If, however, the counter is past the given absolute tick value but outside the guard period, then the driver will assume that this is intentional and let the counter wrap around to/from zero before it expires.

More precisely:

• When counting upwards (see COUNTER_CONFIG_INFO_COUNT_UP) the given absolute tick value must be above (now + guard_period) % top_value to be accepted by the driver.
• When counting downwards, the given absolute tick value must be less than (now + top_value - guard_period) % top_value to be accepted.

Examples:

• counting upwards, now = 4950, top value = 5000, guard period = 100: absolute tick value >= (4950 + 100) % 5000 = 50
• counting downwards, now = 50, top value = 5000, guard period = 100: absolute tick value <= (50 + 5000 - * 100) % 5000 = 4950

If you need only short alarm periods, you can set the guard period very high (e.g. half of the counter top value) which will make it highly unlikely that the counter will ever unintentionally wrap.

The guard period is set to 0 on initialization (no protection).

Parameters

dev	Pointer to the device structure for the driver instance.
ticks	Guard period in counter ticks.
flags	See COUNTER_GUARD_PERIOD_FLAGS.

Return values

0	if successful.
-ENOSYS	if function or flags are not supported.
-EINVAL	if ticks value is invalid.

counter_set_guard_period_64()

int counter_set_guard_period_64	(	const struct device *	dev,
		uint64_t	ticks,
		uint32_t	flags )

#include <zephyr/drivers/counter.h>

Set guard period in counter ticks for 64 bits.

When setting an absolute alarm value close to the current counter value there is a risk that the counter will have counted past the given absolute value before the driver manages to activate the alarm. If this would go unnoticed then the alarm would only expire after the timer has wrapped and reached the given absolute value again after a full timer period. This could take a long time in case of a 32 bit timer. Setting a sufficiently large guard period will help the driver detect unambiguously whether it is late or not.

The guard period should be as many counter ticks as the driver will need at most to actually activate the alarm after the driver API has been called. If the driver finds that the counter has just passed beyond the given absolute tick value but is still close enough to fall within the guard period, it will assume that it is "late", i.e. that the intended expiry time has already passed. Depending on the COUNTER_ALARM_CFG_EXPIRE_WHEN_LATE flag the driver will either ignore the alarm or expire it immediately in such a case.

If, however, the counter is past the given absolute tick value but outside the guard period, then the driver will assume that this is intentional and let the counter wrap around to/from zero before it expires.

More precisely:

• When counting upwards (see COUNTER_CONFIG_INFO_COUNT_UP) the given absolute tick value must be above (now + guard_period) % top_value to be accepted by the driver.
• When counting downwards, the given absolute tick value must be less than (now + top_value - guard_period) % top_value to be accepted.

Examples:

• counting upwards, now = 4950, top value = 5000, guard period = 100: absolute tick value >= (4950 + 100) % 5000 = 50
• counting downwards, now = 50, top value = 5000, guard period = 100: absolute tick value <= (50 + 5000 - * 100) % 5000 = 4950

If you need only short alarm periods, you can set the guard period very high (e.g. half of the counter top value) which will make it highly unlikely that the counter will ever unintentionally wrap.

The guard period is set to 0 on initialization (no protection).

Parameters

dev	Pointer to the device structure for the driver instance.
ticks	Guard period in counter ticks of 64 bits.
flags	See COUNTER_GUARD_PERIOD_FLAGS.

Return values

0	if successful.
-ENOSYS	if function or flags are not supported.
-EINVAL	if ticks value is invalid.

counter_set_top_value()

int counter_set_top_value	(	const struct device *	dev,
		const struct counter_top_cfg *	cfg )

#include <zephyr/drivers/counter.h>

Set counter top value.

Function sets top value and optionally resets the counter to 0 or top value depending on counter direction. On turnaround, counter can be reset and optional callback is periodically called. Top value can only be changed when there is no active channel alarm.

COUNTER_TOP_CFG_DONT_RESET prevents counter reset. When counter is running while top value is updated, it is possible that counter progresses outside the new top value. In that case, error is returned and optionally driver can reset the counter (see COUNTER_TOP_CFG_RESET_WHEN_LATE).

Warning

With CONFIG_COUNTER_64BITS_TICKS enabled this function sets the lower 32 bits of the max top value. Use counter_set_top_value_64() to get the full 64 bit value if it is expected to exceed 32 bits.

Parameters

dev	Pointer to the device structure for the driver instance.
cfg	Configuration. Cannot be NULL.

Return values

0	If successful.
-ENOTSUP	if request is not supported (e.g. top value cannot be changed or counter cannot/must be reset during top value update).
-EBUSY	if any alarm is active.
-ETIME	if COUNTER_TOP_CFG_DONT_RESET was set and new top value is smaller than current counter value (counter counting up).

counter_set_top_value_64()

int counter_set_top_value_64	(	const struct device *	dev,
		const struct counter_top_cfg_64 *	cfg )

#include <zephyr/drivers/counter.h>

Set counter top value for 64 bits.

Function sets top value and optionally resets the counter to 0 or top value depending on counter direction. On turnaround, counter can be reset and optional callback is periodically called. Top value can only be changed when there is no active channel alarm.

COUNTER_TOP_CFG_DONT_RESET prevents counter reset. When counter is running while top value is updated, it is possible that counter progresses outside the new top value. In that case, error is returned and optionally driver can reset the counter (see COUNTER_TOP_CFG_RESET_WHEN_LATE).

Parameters

dev	Pointer to the device structure for the driver instance.
cfg	Configuration. Cannot be NULL.

Return values

0	If successful.
-ENOTSUP	if request is not supported (e.g. top value cannot be changed or counter cannot/must be reset during top value update).
-EBUSY	if any alarm is active.
-ETIME	if COUNTER_TOP_CFG_DONT_RESET was set and new top value is smaller than current counter value (counter counting up).

counter_set_value()

int counter_set_value	(	const struct device *	dev,
		uint32_t	ticks )

#include <zephyr/drivers/counter.h>

Set current counter value.

Parameters

dev	Pointer to the device structure for the driver instance.
ticks	Tick value to set

Return values

0	If successful.
Negative	error code on failure setting the counter value

counter_set_value_64()

int counter_set_value_64	(	const struct device *	dev,
		uint64_t	ticks )

#include <zephyr/drivers/counter.h>

Set current counter 64-bit value.

Parameters

dev	Pointer to the device structure for the driver instance.
ticks	Tick value to set in 64 bits

Return values

0	If successful.
<0	Negative error code on failure setting the counter value

counter_start()

int counter_start

(

const struct device *

dev

)

#include <zephyr/drivers/counter.h>

Start counter device in free running mode.

Parameters

dev	Pointer to the device structure for the driver instance.

Return values

0	If successful.
<0	Negative errno code if failure.

counter_stop()

int counter_stop

(

const struct device *

dev

)

#include <zephyr/drivers/counter.h>

Stop counter device.

Parameters

dev	Pointer to the device structure for the driver instance.

Return values

0	If successful.
-ENOTSUP	if the device doesn't support stopping the counter.

counter_ticks_to_ns()

uint64_t counter_ticks_to_ns	(	const struct device *	dev,
		uint32_t	ticks )

#include <zephyr/drivers/counter.h>

Function to convert ticks to nanoseconds.

Parameters

[in]	dev	Pointer to the device structure for the driver instance.
[in]	ticks	Ticks.

Returns

Converted nanoseconds.

counter_ticks_to_ns_64()

uint64_t counter_ticks_to_ns_64	(	const struct device *	dev,
		uint64_t	ticks )

#include <zephyr/drivers/counter.h>

Function to convert ticks with 64 bits to nanoseconds.

Parameters

[in]	dev	Pointer to the device structure for the driver instance.
[in]	ticks	Ticks in 64 bits.

Returns

Converted nanoseconds.

counter_ticks_to_us()

uint64_t counter_ticks_to_us	(	const struct device *	dev,
		uint32_t	ticks )

#include <zephyr/drivers/counter.h>

Function to convert ticks to microseconds.

Parameters

[in]	dev	Pointer to the device structure for the driver instance.
[in]	ticks	Ticks.

Returns

Converted microseconds.

counter_ticks_to_us_64()

uint64_t counter_ticks_to_us_64	(	const struct device *	dev,
		uint64_t	ticks )

#include <zephyr/drivers/counter.h>

Function to convert ticks with 64 bits to microseconds.

Parameters

[in]	dev	Pointer to the device structure for the driver instance.
[in]	ticks	Ticks in 64 bits.

Returns

Converted microseconds.

counter_us_to_ticks()

uint32_t counter_us_to_ticks	(	const struct device *	dev,
		uint64_t	us )

#include <zephyr/drivers/counter.h>

Function to convert microseconds to ticks.

Parameters

[in]	dev	Pointer to the device structure for the driver instance.
[in]	us	Microseconds.

Returns

Converted ticks. Ticks will be saturated if exceed 32 bits.

counter_us_to_ticks_64()

uint64_t counter_us_to_ticks_64	(	const struct device *	dev,
		uint64_t	us )

#include <zephyr/drivers/counter.h>

Function to convert microseconds to ticks with 64 bits.

Parameters

[in]	dev	Pointer to the device structure for the driver instance.
[in]	us	Microseconds.

Returns

Converted ticks as a uint64_t