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Diffstat (limited to 'static/netbsd/man4/gpio.4')
| -rw-r--r-- | static/netbsd/man4/gpio.4 | 245 |
1 files changed, 245 insertions, 0 deletions
diff --git a/static/netbsd/man4/gpio.4 b/static/netbsd/man4/gpio.4 new file mode 100644 index 00000000..6f58df63 --- /dev/null +++ b/static/netbsd/man4/gpio.4 @@ -0,0 +1,245 @@ +.\" $NetBSD: gpio.4,v 1.39 2025/10/24 23:16:10 brad Exp $ +.\" $OpenBSD: gpio.4,v 1.5 2004/11/23 09:39:29 reyk 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 May 4, 2021 +.Dt GPIO 4 +.Os +.Sh NAME +.Nm gpio +.Nd General Purpose Input/Output +.Sh SYNOPSIS +.Cd "gpio* at elansc?" +.Cd "gpio* at emcfan?" +.Cd "gpio* at epgpio?" +.Cd "gpio* at gcscpcib?" +.Cd "gpio* at gpiosim?" +.Cd "gpio* at gscpcib?" +.Cd "gpio* at ichlpcib?" +.Cd "gpio* at nsclpcsio?" +.Cd "gpio* at sc16is7xx?" +.Cd "gpio* at soekrisgpio?" +.Cd "gpio* at ppbus?" +.Cd "gpio* at ptcd?" +.Cd "gpio* at umcpmio?" +.Cd "gpio* at wbsio?" +.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 +Whether the layout of the GPIO device can be configured is subject to +authorization by the +.Xr kauth 9 +framework. +.Pp +If for example +.Xr secmodel_securelevel 9 +is active, the layout of the GPIO device is defined at a securelevel +less than 1, 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 a securelevel less than 1. +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: +.Pp +.Bl -tag -width XXXX -compact +.It Dv GPIOINFO ( 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 +.Pp +.It Dv GPIOREAD ( struct gpio_req ) +Returns the input pin value in the +.Fa gpio_req +structure: +.Bd -literal +#define GPIOMAXNAME 64 + +struct gpio_req { + char gp_name[GPIOMAXNAME]; /* 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. +If both are set, gp_name takes precedence. +On return, the +.Fa gp_name +field contains the current name of the pin, if set by the controller driver +or an earlier call to +.Dv GPIOSET . +.Pp +.It Dv GPIOWRITE ( struct gpio_req ) +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. +.Pp +.It Dv GPIOTOGGLE ( struct gpio_req ) +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. +.Pp +.It Dv GPIOSET ( struct gpio_set ) +Changes pin configuration flags with the new ones provided in the +.Fa gpio_set +structure: +.Bd -literal +#define GPIOMAXNAME 64 + +struct gpio_set { + char gp_name[GPIOMAXNAME]; /* pin name */ + int gp_pin; /* pin number */ + int gp_caps; /* pin capabilities (ro) */ + int gp_flags; /* pin configuration flags */ + char gp_name2[GPIOMAXNAME]; /* 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 +.It Dv GPIO_PIN_PULSATE +pulsate output +.It Dv GPIO_PIN_ALT0 - +.It Dv GPIO_PIN_ALT7 +select alternate pin function 0 to 7 +.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 GPIOSET +will be accessible at securelevels greater than 0. +.Pp +.It Dv GPIOUNSET ( struct gpio_set ) +Unset the specified pin, i.e. clear its name and make it inaccessible +at securelevels greater than 0. +.Pp +.It Dv GPIOATTACH ( 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 */ + uint32_t ga_mask; /* binary mask */ + uint32_t ga_flags; /* driver dependent */ +}; +.Ed +.Pp +The +.Xr drvctl 8 +command can be used to detach a device from a gpio pin. +.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 drvctl 8 , +.Xr gpioctl 8 +.Sh HISTORY +The +.Nm +device first appeared in +.Ox 3.6 +and +.Nx 4.0 . +.Sh AUTHORS +.An -nosplit +The +.Nm +driver was written by +.An Alexander Yurchenko Aq Mt grange@openbsd.org . +.Nm +was ported to +.Nx +by +.An Jared D. McNeill Aq Mt jmcneill@NetBSD.org . +Runtime device attachment was added by +.An Marc Balmer Aq Mt marc@msys.ch . +.Sh BUGS +Event capabilities are not supported. |