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Diffstat (limited to 'static/openbsd/man4/gpio.4')
| -rw-r--r-- | static/openbsd/man4/gpio.4 | 219 |
1 files changed, 219 insertions, 0 deletions
diff --git a/static/openbsd/man4/gpio.4 b/static/openbsd/man4/gpio.4 new file mode 100644 index 00000000..ebabe04f --- /dev/null +++ b/static/openbsd/man4/gpio.4 @@ -0,0 +1,219 @@ +.\" $OpenBSD: gpio.4,v 1.30 2026/04/21 19:58:21 jca Exp $ +.\" +.\" Copyright (c) 2004 Alexander Yurchenko <grange@openbsd.org> +.\" +.\" Permission to use, copy, modify, and distribute this software for any +.\" purpose with or without fee is hereby granted, provided that the above +.\" copyright notice and this permission notice appear in all copies. +.\" +.\" THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES +.\" WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF +.\" MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR +.\" ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES +.\" WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN +.\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF +.\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. +.\" +.Dd $Mdocdate: April 21 2026 $ +.Dt GPIO 4 +.Os +.Sh NAME +.Nm gpio +.Nd General Purpose Input/Output +.Sh SYNOPSIS +.Cd "gpio* at ath?" +.Cd "gpio* at bcmgpio?" Pq arm64, armv7 +.Cd "gpio* at glxpcib?" Pq i386 +.Cd "gpio* at gscpcib?" Pq i386 +.Cd "gpio* at isagpio?" +.Cd "gpio* at mpfgpio?" Pq riscv64 +.Cd "gpio* at nsclpcsio?" +.Cd "gpio* at omgpio?" Pq armv7 +.Cd "gpio* at pcagpio?" +.Cd "gpio* at pcaled?" +.Cd "gpio* at sfgpio?" Pq riscv64 +.Cd "gpio* at skgpio?" Pq amd64, i386 +.Cd "gpio* at smtgpio?" Pq riscv64 +.Cd "gpio* at sxipio?" Pq arm64, armv7 +.Cd "gpio0 at voyager?" Pq loongson +.Pp +.In sys/types.h +.In sys/gpio.h +.In sys/ioctl.h +.Sh DESCRIPTION +The +.Nm +device attaches to the GPIO +controller and provides a uniform programming interface to its pins. +.Pp +Each GPIO controller with an attached +.Nm +device has an associated device file under the +.Pa /dev +directory, e.g.\& +.Pa /dev/gpio0 . +Access from userland is performed through +.Xr ioctl 2 +calls on these devices. +.Pp +The layout of the GPIO device is defined at securelevel 0, i.e. typically +during system boot, and cannot be changed later. +GPIO pins can be configured and given a symbolic name and device drivers +that use GPIO pins can be attached to the +.Nm +device at securelevel 0. +All other pins will not be accessible once the runlevel has been raised. +.Sh IOCTL INTERFACE +The following structures and constants are defined in the +.In sys/gpio.h +header file: +.Bl -tag -width XXXX +.It Dv GPIOINFO Fa "struct gpio_info" +Returns information about the GPIO +controller in the +.Fa gpio_info +structure: +.Bd -literal +struct gpio_info { + int gpio_npins; /* total number of pins available */ +}; +.Ed +.It Dv GPIOPINREAD Fa "struct gpio_pin_op" +Returns the input pin value in the +.Fa gpio_pin_op +structure: +.Bd -literal +#define GPIOPINMAXNAME 64 + +struct gpio_pin_op { + char gp_name[GPIOPINMAXNAME]; /* pin name */ + int gp_pin; /* pin number */ + int gp_value; /* value */ +}; +.Ed +.Pp +The +.Fa gp_name +or +.Fa gp_pin +field must be set before calling. +.It Dv GPIOPINWRITE Fa "struct gpio_pin_op" +Writes the output value to the pin. +The value set in the +.Fa gp_value +field must be either +.Dv GPIO_PIN_LOW +(logical 0) or +.Dv GPIO_PIN_HIGH +(logical 1). +On return, the +.Fa gp_value +field contains the old pin state. +.It Dv GPIOPINTOGGLE Fa "struct gpio_pin_op" +Toggles the pin output value, i.e. changes it to the opposite. +.Fa gp_value +field is ignored and on return contains the old pin state. +.It Dv GPIOPINSET Fa "struct gpio_pin_set" +Changes pin configuration flags with the new ones provided in the +.Fa gpio_pin_set +structure: +.Bd -literal +#define GPIOPINMAXNAME 64 + +struct gpio_pin_set { + char gp_name[GPIOPINMAXNAME]; /* pin name */ + int gp_pin; /* pin number */ + int gp_caps; /* pin capabilities (ro) */ + int gp_flags; /* pin configuration flags */ + char gp_name2[GPIOPINMAXNAME]; /* new name */ +}; +.Ed +.Pp +The +.Fa gp_flags +field is a combination of the following flags: +.Pp +.Bl -tag -width GPIO_PIN_OPENDRAIN -compact +.It Dv GPIO_PIN_INPUT +input direction +.It Dv GPIO_PIN_OUTPUT +output direction +.It Dv GPIO_PIN_INOUT +bi-directional +.It Dv GPIO_PIN_OPENDRAIN +open-drain output +.It Dv GPIO_PIN_PUSHPULL +push-pull output +.It Dv GPIO_PIN_TRISTATE +output disabled +.It Dv GPIO_PIN_PULLUP +internal pull-up enabled +.It Dv GPIO_PIN_PULLDOWN +internal pull-down enabled +.It Dv GPIO_PIN_INVIN +invert input +.It Dv GPIO_PIN_INVOUT +invert output +.El +.Pp +Note that the GPIO controller +may not support all of these flags. +On return the +.Fa gp_caps +field contains flags that are supported. +If no flags are specified, the pin configuration stays unchanged. +.Pp +Only GPIO pins that have been set using +.Ar GPIOPINSET +will be accessible at securelevels greater than 0. +.It Dv GPIOPINUNSET Fa "struct gpio_pin_set" +Unset the specified pin, i.e. clear its name and make it inaccessible +at securelevels greater than 0. +.It Dv GPIOATTACH Fa "struct gpio_attach" +Attach the device described in the +.Fa gpio_attach +structure on this gpio device. +.Bd -literal +struct gpio_attach { + char ga_dvname[16]; /* device name */ + int ga_offset; /* pin number */ + u_int32_t ga_mask; /* binary mask */ +}; +.Ed +.It Dv GPIODETACH Fa "struct gpio_attach" +Detach a device from this gpio device that was previously attached using the +.Dv GPIOATTACH +.Xr ioctl 2 . +The +.Fa ga_offset +and +.Fa ga_mask +fields of the +.Fa gpio_attach +structure are ignored. +.El +.Sh FILES +.Bl -tag -width "/dev/gpiou" -compact +.It /dev/gpio Ns Ar u +GPIO device unit +.Ar u +file. +.El +.Sh SEE ALSO +.Xr ioctl 2 , +.Xr gpioctl 8 +.Sh HISTORY +The +.Nm +device first appeared in +.Ox 3.6 . +.Sh AUTHORS +.An -nosplit +The +.Nm +driver was written by +.An Alexander Yurchenko Aq Mt grange@openbsd.org . +Runtime device attachment was added by +.An Marc Balmer Aq Mt mbalmer@openbsd.org . +.Sh BUGS +Event capabilities are not supported. |