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libgpio: Add and document gpio interrupt utility functions
Add utility functions for configuring gpio interrupts and document file operations. Reviewed by: vexeduxr, ziaee Differential Revision: https://reviews.freebsd.org/D52102
This commit is contained in:
Evgenii Ivanov
Ahmad Khalifa
parent
e323aaaf39
commit
ccc6cf3b67
4 changed files with 102 additions and 3 deletions
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@ -27,6 +27,8 @@ MLINKS= gpio.3 gpio_open.3 \
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gpio.3 gpio_pin_pulldown.3 \
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gpio.3 gpio_pin_invin.3 \
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gpio.3 gpio_pin_invout.3 \
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gpio.3 gpio_pin_pulsate.3
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gpio.3 gpio_pin_pulsate.3 \
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gpio.3 gpio_configure_events.3 \
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gpio.3 gpio_fileno.3
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.include <bsd.lib.mk>
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@ -23,7 +23,7 @@
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.Dd July 1, 2015
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.Dd September 3, 2025
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.Dt GPIO 3
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.Os
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.Sh NAME
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@ -79,6 +79,10 @@
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.Fn gpio_pin_invout "gpio_handle_t handle" "gpio_pin_t pin"
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.Ft int
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.Fn gpio_pin_pulsate "gpio_handle_t handle" "gpio_pin_t pin"
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.Ft int
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.Fn gpio_configure_events "gpio_handle_t handle" "uint32_t report_type" "uint32_t fifo_size"
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.Ft int
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.Fn gpio_fileno "gpio_handle_t handle"
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.Sh DESCRIPTION
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The
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.Nm libgpio
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@ -125,7 +129,7 @@ The pin number should also be passed in through the
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variable.
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All other structure members will be ignored by this function.
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The list of flags can be found in
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.Pa /usr/include/sys/gpio.h .
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.In sys/gpio.h .
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.Pp
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The get or set the state of a GPIO pin, the functions
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.Fn gpio_pin_get
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@ -156,6 +160,66 @@ and
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.Fn gpio_pin_pulsate
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are wrappers around
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.Fn gpio_pin_set_flags .
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.Pp
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The function
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.Fn gpio_configure_events
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configures the interrupt report type and FIFO size for buffered
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gpio interrupts.
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The report type is specified by one of the following values:
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.Bl -tag -width indent
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.It Dv GPIO_EVENT_REPORT_DETAIL
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Events are reported using
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.Ft struct gpio_event_detail .
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.It Dv GPIO_EVENT_REPORT_SUMMARY
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Events are reported using
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.Ft struct gpio_event_summary .
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.El
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.Pp
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By default, the report type is
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.Dv GPIO_EVENT_REPORT_DETAIL ,
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with a default FIFO size of 2 * number of pins belonging to the
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.Ft gpio_device_t
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instance.
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The FIFO argument is only meaningful when
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.Fa report_type
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is
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.Dv GPIO_EVENT_REPORT_DETAIL .
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The structures associated with each report type are defined in
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.In sys/gpio.h .
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This setting is tracked on a per device instance basis.
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The FIFO size cannot be reduced below the default value,
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nor can it be decreased after it has been increased.
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If any pin on the device has already been configured for interrupts,
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.Fn gpio_configure_events
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fails and returns -1.
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On success 0 is returned.
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.Pp
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The function
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.Fn gpio_fileno
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returns the file descriptor associated with the
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.Ft gpio_handle_t
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instance.
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.Pp
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File operations have the following semantics:
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.Bl -tag -width "read (2)"
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.It Xr read 2
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Read one or more gpio interrupts that have occured
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since the last successful
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.Xr read 2 .
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The results are placed into the output buffer
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of the type previously established via
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.Fn gpio_configure_events .
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If there are no pending interrupts,
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.Xr read 2
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blocks until an interrupt occurs, unless
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.Dv O_NONBLOCK
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is set.
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.It Xr poll 2
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When receiving notification via
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.Xr poll 2
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or similar interfaces, the file descriptor becomes readable when
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one or more gpio interrupts are pending.
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.El
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.Sh EXAMPLES
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The following example shows how to configure pin 16 as output and then
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drive it high:
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@ -274,3 +274,23 @@ gpio_pin_pulsate(gpio_handle_t handle, gpio_pin_t pin)
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{
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return (gpio_pin_set_flag(handle, pin, GPIO_PIN_PULSATE));
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}
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int
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gpio_configure_events(gpio_handle_t handle, uint32_t report_type,
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uint32_t fifo_size)
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{
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struct gpio_event_config gpevent_config;
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gpevent_config.gp_report_type = report_type;
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gpevent_config.gp_fifo_size = fifo_size;
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if (ioctl(handle, GPIOCONFIGEVENTS, &gpevent_config) < 0)
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return (-1);
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return (0);
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}
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int
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gpio_fileno(gpio_handle_t handle)
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{
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return (handle);
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}
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@ -102,6 +102,19 @@ int gpio_pin_pulldown(gpio_handle_t, gpio_pin_t);
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int gpio_pin_invin(gpio_handle_t, gpio_pin_t);
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int gpio_pin_invout(gpio_handle_t, gpio_pin_t);
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int gpio_pin_pulsate(gpio_handle_t, gpio_pin_t);
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/*
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* GPIO event reporting configuration
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*
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* Set the event reporting type, the default being GPIO_EVENT_REPORT_DETAIL,
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* and fifo size of 2 * number of pins belonging to the gpioc device instance.
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* FIFO size can only be changed when report_type is GPIO_EVENT_REPORT_DETAIL.
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*/
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int gpio_configure_events(gpio_handle_t, uint32_t, uint32_t);
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/*
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* Retrieve the file descriptor associated with gpio_handle_t, which can
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* be used for gpio interrupts.
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*/
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int gpio_fileno(gpio_handle_t);
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__END_DECLS
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