Singleton object used to manage GPIO. More...

#include <sg_GpioManagement.hpp>

Public Types
enum	EDirection { EDirection::kUnknown = 0, EDirection::kInput, EDirection::kOutput }

enum	EValue { EValue::kInvalid = -1, EValue::kLow = 0, EValue::kHigh = 1 }

typedef std::map< GPIO, EDirection >	MGPIODirection

Public Member Functions
	~GpioManagement (void)
	Destructor. More...

GpioManagement &	cleanup (void)
	Perform any necessary cleanup, such as releasing (unexporting) any GPIOs that were originally exported by this instance of the SG++ library. More...

SGPIO	get_exported (void)
	Get the set of exported GPIO. More...

MGPIODirection	get_direction_map (void)
	Get the map of exported GPIO and the direction for each one. More...

GpioManagement &	gpio_export (const GPIO gpio, const EDirection direction=EDirection::kOutput)
	Tell the Linux kernel to export a GPIO. More...

GpioManagement &	gpio_unexport (const GPIO gpio)
	Tell the Linux kernel a GPIO is no longer needed. More...

GpioManagement &	set_direction (const GPIO gpio, const EDirection direction=EDirection::kOutput)
	Tell the Linux kernel if a GPIO will be used to reading or writing. More...

bool	is_exported (const GPIO gpio, int number_of_times_to_check=1)
	See if the given GPIO has been exported. More...

GpioManagement &	set_value (const GPIO gpio, const EValue &value)
	Set the given GPIO low or high. More...

EValue	get_value (const GPIO gpio)
	Get the given GPIO value. More...


GpioManagement &	set_value (const GPIO gpio, const bool set_to_high)
	Set the given GPIO high when `TRUE` and to low when `FALSE`. More...

GpioManagement &	set_low (const GPIO gpio)
	Set the given GPIO high when `TRUE` and to low when `FALSE`. More...

GpioManagement &	set_high (const GPIO gpio)
	Set the given GPIO high when `TRUE` and to low when `FALSE`. More...


bool	get_value (const GPIO gpio, bool &value)
	Alias for get_value(). More...

bool	get_bool (const GPIO gpio)
	Alias for get_value(). More...

Static Public Member Functions
static GpioManagement &	get (void)
	Get the singleton. More...

Public Attributes
bool	unexport_all_gpio_on_destruction
	Determine whether all exported GPIO are automatically unexported on destruction. More...

Friends
class	SGpp
	Normally GpioManagement in created and managed by SGpp. More...

Detailed Description

Singleton object used to manage GPIO.

Obtain a copy of the singleton through SG::SGpp::gpio.

See also: GPIO in Linux is explained here: https://www.kernel.org/doc/Documentation/gpio/sysfs.txt

Member Typedef Documentation

◆ MGPIODirection

typedef std::map<GPIO, EDirection> SG::GpioManagement::MGPIODirection

Member Enumeration Documentation

◆ EDirection

enum SG::GpioManagement::EDirection

strong

Enumerator
kUnknown
kInput
kOutput

◆ EValue

enum SG::GpioManagement::EValue

strong

Enumerator
kInvalid
kLow
kHigh

Constructor & Destructor Documentation

◆ ~GpioManagement()

SG::GpioManagement::~GpioManagement ( void )

Destructor.

See also: unexport_all_gpio_on_destruction

References SG::SGpp::cleanup().

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Member Function Documentation

◆ cleanup()

SG::GpioManagement & SG::GpioManagement::cleanup ( void )

Perform any necessary cleanup, such as releasing (unexporting) any GPIOs that were originally exported by this instance of the SG++ library.

See also: unexport_all_gpio_on_destruction

References SG::SGpp::gpio.

Referenced by SG::SGpp::cleanup().

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◆ get()

SG::GpioManagement & SG::GpioManagement::get ( void )

static

Get the singleton.

◆ get_bool()

bool SG::GpioManagement::get_bool ( const GPIO gpio )

inline

Alias for get_value().

Returns: TRUE for high and FALSE for low.

References get_value().

Referenced by SG::Button::is_down(), and SG::LEDBar::send_data().

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◆ get_direction_map()

SG::GpioManagement::MGPIODirection SG::GpioManagement::get_direction_map ( void )

Get the map of exported GPIO and the direction for each one.

This only includes the GPIOs exported by this instance of the SG++ library.

See also: get_exported()

◆ get_exported()

SG::SGPIO SG::GpioManagement::get_exported ( void )

Get the set of exported GPIO.

This only includes the GPIOs exported by this instance of the SG++ library.

See also: get_direction_map()

◆ get_value() [1/2]

SG::GpioManagement::EValue SG::GpioManagement::get_value ( const GPIO gpio )

Get the given GPIO value.

The GPIO must be exported.

See also: /sys/class/gpio/gpioN/value where "N" is the GPIO number.

Exceptions

std::system_error if the GPIO value file cannot be opened with read access.

References kHigh, and SG::BeagleBone::Detect::to_string().

Referenced by get_bool(), and set_high().

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◆ get_value() [2/2]

bool SG::GpioManagement::get_value	(	const GPIO	gpio,
		bool &	value
	)

inline

Alias for get_value().

Returns: TRUE for high and FALSE for low.

References get_value(), and kHigh.

Referenced by get_value().

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◆ gpio_export()

SG::GpioManagement & SG::GpioManagement::gpio_export	(	const GPIO	gpio,
		const EDirection	direction = `EDirection::kOutput`
	)

Tell the Linux kernel to export a GPIO.

See also: /sys/class/gpio/export

Exceptions

std::invalid_argument	if the specified GPIO has already been exported.
std::system_error	if the GPIO export file cannot be opened with write access.
std::runtime_error	if the specified GPIO fails to export after several tries.

References SG::SGpp::gpio, SG::kUnknown, and SG::BeagleBone::Detect::to_string().

Referenced by SG::Button::Button(), SG::Buzzer::Buzzer(), SG::ChainableRGBLED::ChainableRGBLED(), SG::LEDBar::LEDBar(), and SG::VariableColorLED::VariableColorLED().

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◆ gpio_unexport()

SG::GpioManagement & SG::GpioManagement::gpio_unexport ( const GPIO gpio )

Tell the Linux kernel a GPIO is no longer needed.

See also: /sys/class/gpio/unexport

Exceptions

std::system_error if the GPIO unexport file cannot be opened with write access.

Referenced by SG::Button::~Button(), SG::Buzzer::~Buzzer(), SG::ChainableRGBLED::~ChainableRGBLED(), SG::LEDBar::~LEDBar(), and SG::VariableColorLED::~VariableColorLED().

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◆ is_exported()

bool SG::GpioManagement::is_exported	(	const GPIO	gpio,
		int	number_of_times_to_check = `1`
	)

See if the given GPIO has been exported.

If the GPIO was just exported, it may be necessary to retry several times, where it pauses briefly between each attempt. By default, it only checks once.

Returns: true if the GPIO is already exported.; false if the GPIO has not been exported.

Note: This method checks all GPIOs, not only the ones originally exported by this library.

See also: /sys/class/gpio/gpioN where "N" is the GPIO number.

References SG::BeagleBone::Detect::to_string().

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◆ set_direction()

SG::GpioManagement & SG::GpioManagement::set_direction	(	const GPIO	gpio,
		const EDirection	direction = `EDirection::kOutput`
	)

Tell the Linux kernel if a GPIO will be used to reading or writing.

A GPIO must first be exported for this to work. This normally doesn't need to be called unless the direction is changing, since gpio_export() allows the direction to be set when the GPIO is originally exported.

See also: gpio_export(); /sys/class/gpio/gpioN/direction where "N" is the GPIO number.

Exceptions

invalid_argument	if the specified GPIO has not been exported.
std::system_error	if the GPIO direction file cannot be opened with write access.

References SG::SGpp::gpio, and SG::BeagleBone::Detect::to_string().

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◆ set_high()

GpioManagement& SG::GpioManagement::set_high ( const GPIO gpio )

inline

Set the given GPIO high when TRUE and to low when FALSE.

The GPIO must be exported, and the direction must be set to EDirection::kOutput.

See also: gpio_export(); set_direction(); /sys/class/gpio/gpioN/value where "N" is the GPIO number.Alias for set_value()

References get_value(), and set_value().

Referenced by SG::GroveGPIO::send_byte(), SG::LEDBar::send_data(), SG::VariableColorLED::turn_off(), SG::Buzzer::turn_off(), SG::Buzzer::turn_on(), and SG::VariableColorLED::turn_on().

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◆ set_low()

GpioManagement& SG::GpioManagement::set_low ( const GPIO gpio )

inline

Set the given GPIO high when TRUE and to low when FALSE.

The GPIO must be exported, and the direction must be set to EDirection::kOutput.

See also: gpio_export(); set_direction(); /sys/class/gpio/gpioN/value where "N" is the GPIO number.Alias for set_value()

References set_value().

Referenced by SG::GroveGPIO::send_byte(), SG::LEDBar::send_data(), SG::Buzzer::turn_off(), SG::VariableColorLED::turn_off(), SG::VariableColorLED::turn_on(), and SG::Buzzer::turn_on().

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◆ set_value() [1/2]

SG::GpioManagement & SG::GpioManagement::set_value	(	const GPIO	gpio,
		const EValue &	value
	)

Set the given GPIO low or high.

The GPIO must be exported, and the direction must be set to EDirection::kOutput.

See also: gpio_export(); set_direction(); /sys/class/gpio/gpioN/value where "N" is the GPIO number.

Exceptions

invalid_argument	if the value is anything other than kLow or kHigh.
invalid_argument	if the specified GPIO has not been exported.
std::system_error	if the GPIO value file cannot be opened with write access.

References SG::BeagleBone::Detect::to_string().

Referenced by SG::LEDBar::send_data(), set_high(), and set_low().

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◆ set_value() [2/2]

GpioManagement& SG::GpioManagement::set_value	(	const GPIO	gpio,
		const bool	set_to_high
	)

inline

Set the given GPIO high when TRUE and to low when FALSE.

The GPIO must be exported, and the direction must be set to EDirection::kOutput.

See also: gpio_export(); set_direction(); /sys/class/gpio/gpioN/value where "N" is the GPIO number.Alias for set_value()

Friends And Related Function Documentation

◆ SGpp

friend class SGpp

friend

Normally GpioManagement in created and managed by SGpp.

See also: SG::SGpp::gpio;

Member Data Documentation

◆ unexport_all_gpio_on_destruction

bool SG::GpioManagement::unexport_all_gpio_on_destruction

Determine whether all exported GPIO are automatically unexported on destruction.

This only includes GPIOs that were exported by the SG++ library. Default is true to ensure all GPIOs are released. The equivalent functionality can be obtained at any time by manually calling cleanup().

The documentation for this class was generated from the following files:

src-sg++/sg_GpioManagement.hpp
src-sg++/sg_GpioManagement.cpp

Public Types

Public Member Functions

Static Public Member Functions

Public Attributes

Friends

Detailed Description

Member Typedef Documentation

◆ MGPIODirection

Member Enumeration Documentation

◆ EDirection

◆ EValue

Constructor & Destructor Documentation

◆ ~GpioManagement()

Member Function Documentation

◆ cleanup()

◆ get()

◆ get_bool()

◆ get_direction_map()

◆ get_exported()

◆ get_value() [1/2]

◆ get_value() [2/2]

◆ gpio_export()

◆ gpio_unexport()

◆ is_exported()

◆ set_direction()

◆ set_high()

◆ set_low()

◆ set_value() [1/2]

◆ set_value() [2/2]

Friends And Related Function Documentation

◆ SGpp

Member Data Documentation

◆ unexport_all_gpio_on_destruction