summaryrefslogtreecommitdiffstats
path: root/man4/lirc.4
diff options
context:
space:
mode:
Diffstat (limited to 'man4/lirc.4')
-rw-r--r--man4/lirc.4423
1 files changed, 0 insertions, 423 deletions
diff --git a/man4/lirc.4 b/man4/lirc.4
deleted file mode 100644
index 227172f..0000000
--- a/man4/lirc.4
+++ /dev/null
@@ -1,423 +0,0 @@
-.\" Copyright (c) 2015-2016, Alec Leamas
-.\" Copyright (c) 2018, Sean Young <sean@mess.org>
-.\"
-.\" SPDX-License-Identifier: GPL-2.0-or-later
-.TH lirc 4 2023-10-31 "Linux man-pages 6.7"
-.SH NAME
-lirc \- lirc devices
-.SH DESCRIPTION
-The
-.I /dev/lirc*
-character devices provide a low-level
-bidirectional interface to infra-red (IR) remotes.
-Most of these devices can receive, and some can send.
-When receiving or sending data, the driver works in two different modes
-depending on the underlying hardware.
-.P
-Some hardware (typically TV-cards) decodes the IR signal internally
-and provides decoded button presses as scancode values.
-Drivers for this kind of hardware work in
-.B LIRC_MODE_SCANCODE
-mode.
-Such hardware usually does not support sending IR signals.
-Furthermore, such hardware can only decode a limited set of IR protocols,
-usually only the protocol of the specific remote which is
-bundled with, for example, a TV-card.
-.P
-Other hardware provides a stream of pulse/space durations.
-Such drivers work in
-.B LIRC_MODE_MODE2
-mode.
-Such hardware can be used with (almost) any kind of remote.
-This type of hardware can also be used in
-.B LIRC_MODE_SCANCODE
-mode, in which case the kernel IR decoders will decode the IR.
-These decoders can be written in extended BPF (see
-.BR bpf (2))
-and attached to the
-.B lirc
-device.
-Sometimes, this kind of hardware also supports
-sending IR data.
-.P
-The \fBLIRC_GET_FEATURES\fR ioctl (see below) allows probing for whether
-receiving and sending is supported, and in which modes, amongst other
-features.
-.\"
-.SS Reading input with the LIRC_MODE_MODE2 mode
-In the \fBLIRC_MODE_MODE2 mode\fR, the data returned by
-.BR read (2)
-provides 32-bit values representing a space or a pulse duration.
-The time of the duration (microseconds) is encoded in the lower 24 bits.
-Pulse (also known as flash)
-indicates a duration of infrared light being detected,
-and space (also known as gap) indicates a duration with no infrared.
-If the duration of space exceeds the inactivity timeout,
-a special timeout package is delivered,
-which marks the end of a message.
-The upper 8 bits indicate the type of package:
-.TP 4
-.B LIRC_MODE2_SPACE
-Value reflects a space duration (microseconds).
-.TP 4
-.B LIRC_MODE2_PULSE
-Value reflects a pulse duration (microseconds).
-.TP 4
-.B LIRC_MODE2_FREQUENCY
-Value reflects a frequency (Hz); see the
-.B LIRC_SET_MEASURE_CARRIER_MODE
-ioctl.
-.TP 4
-.B LIRC_MODE2_TIMEOUT
-Value reflects a space duration (microseconds).
-The package reflects a timeout; see the
-.B LIRC_SET_REC_TIMEOUT_REPORTS
-ioctl.
-.\"
-.TP 4
-.B LIRC_MODE2_OVERFLOW
-The IR receiver encountered an overflow,
-and as a result data is missing
-(since Linux 5.18).
-.SS Reading input with the LIRC_MODE_SCANCODE mode
-In the \fBLIRC_MODE_SCANCODE\fR
-mode, the data returned by
-.BR read (2)
-reflects decoded button presses, in the struct \fIlirc_scancode\fR.
-The scancode is stored in the \fIscancode\fR field, and the IR protocol
-is stored in \fIrc_proto\fR.
-This field has one the values of the \fIenum rc_proto\fR.
-.\"
-.SS Writing output with the LIRC_MODE_PULSE mode
-The data written to the character device using
-.BR write (2)
-is a pulse/space sequence of integer values.
-Pulses and spaces are only marked implicitly by their position.
-The data must start and end with a pulse, thus it must always include
-an odd number of samples.
-The
-.BR write (2)
-function blocks until the data has been transmitted by the
-hardware.
-If more data is provided than the hardware can send, the
-.BR write (2)
-call fails with the error
-.BR EINVAL .
-.SS Writing output with the LIRC_MODE_SCANCODE mode
-The data written to the character devices must be a single struct
-\fIlirc_scancode\fR.
-The \fIscancode\fR and \fIrc_proto\fR fields must
-filled in, all other fields must be 0.
-The kernel IR encoders will
-convert the scancode to pulses and spaces.
-The protocol or scancode is invalid, or the
-.B lirc
-device cannot transmit.
-.SH IOCTL COMMANDS
-.nf
-#include <linux/lirc.h> /* But see BUGS */
-\&
-int ioctl(int fd, int cmd, int *val);
-.fi
-.P
-The following
-.BR ioctl (2)
-operations are provided by the
-.B lirc
-character device to probe or change specific
-.B lirc
-hardware settings.
-.SS Always Supported Commands
-\fI/dev/lirc*\fR devices always support the following commands:
-.TP 4
-.BR LIRC_GET_FEATURES " (\fIvoid\fP)"
-Returns a bit mask of combined features bits; see FEATURES.
-.P
-If a device returns an error code for
-.BR LIRC_GET_FEATURES ,
-it is safe to assume it is not a
-.B lirc
-device.
-.\"
-.SS Optional Commands
-Some
-.B lirc
-devices support the commands listed below.
-Unless otherwise stated, these fail with the error \fBENOTTY\fR if the
-operation isn't supported, or with the error \fBEINVAL\fR if the operation
-failed, or invalid arguments were provided.
-If a driver does not announce support of certain features, invoking
-the corresponding ioctls will fail with the error
-.BR ENOTTY .
-.TP
-.BR LIRC_GET_REC_MODE " (\fIvoid\fP)"
-If the
-.B lirc
-device has no receiver, this operation fails with the error
-.BR ENOTTY .
-Otherwise, it returns the receive mode, which will be one of:
-.RS
-.TP
-.B LIRC_MODE_MODE2
-The driver returns a sequence of pulse/space durations.
-.TP
-.B LIRC_MODE_SCANCODE
-The driver returns struct
-.I lirc_scancode
-values, each of which represents
-a decoded button press.
-.RE
-.TP
-.BR LIRC_SET_REC_MODE " (\fIint\fP)"
-Set the receive mode.
-.I val
-is either
-.B LIRC_MODE_SCANCODE
-or
-.BR LIRC_MODE_MODE2 .
-If the
-.B lirc
-device has no receiver, this operation fails with the error
-.B ENOTTY.
-.TP
-.BR LIRC_GET_SEND_MODE " (\fIvoid\fP)"
-Return the send mode.
-.B LIRC_MODE_PULSE
-or
-.B LIRC_MODE_SCANCODE
-is supported.
-If the
-.B lirc
-device cannot send, this operation fails with the error
-.B ENOTTY.
-.TP
-.BR LIRC_SET_SEND_MODE " (\fIint\fP)"
-Set the send mode.
-.I val
-is either
-.B LIRC_MODE_SCANCODE
-or
-.BR LIRC_MODE_PULSE .
-If the
-.B lirc
-device cannot send, this operation fails with the error
-.BR ENOTTY .
-.TP
-.BR LIRC_SET_SEND_CARRIER " (\fIint\fP)"
-Set the modulation frequency.
-The argument is the frequency (Hz).
-.TP
-.BR LIRC_SET_SEND_DUTY_CYCLE " (\fIint\fP)"
-Set the carrier duty cycle.
-.I val
-is a number in the range [0,100] which
-describes the pulse width as a percentage of the total cycle.
-Currently, no special meaning is defined for 0 or 100, but the values
-are reserved for future use.
-.TP
-.BI LIRC_GET_MIN_TIMEOUT( void )
-.TQ
-.BI LIRC_GET_MAX_TIMEOUT( void )
-Some devices have internal timers that can be used to detect when
-there has been no IR activity for a long time.
-This can help
-.BR lircd (8)
-in detecting that an IR signal is finished and can speed up the
-decoding process.
-These operations
-return integer values with the minimum/maximum timeout that can be
-set (microseconds).
-Some devices have a fixed timeout.
-For such drivers,
-.B LIRC_GET_MIN_TIMEOUT
-and
-.B LIRC_GET_MAX_TIMEOUT
-will fail with the error
-.BR ENOTTY .
-.TP
-.BR LIRC_SET_REC_TIMEOUT " (\fIint\fP)"
-Set the integer value for IR inactivity timeout (microseconds).
-To be accepted, the value must be within the limits defined by
-.B LIRC_GET_MIN_TIMEOUT
-and
-.BR LIRC_GET_MAX_TIMEOUT .
-A value of 0 (if supported by the hardware) disables all hardware
-timeouts and data should be reported as soon as possible.
-If the exact value cannot be set, then the next possible value
-.I greater
-than the given value should be set.
-.TP
-.BR LIRC_GET_REC_TIMEOUT " (\fIvoid\fP)"
-Return the current inactivity timeout (microseconds).
-Available since Linux 4.18.
-.TP
-.BR LIRC_SET_REC_TIMEOUT_REPORTS " (\fIint\fP)"
-Enable
-.RI ( val
-is 1) or disable
-.RI ( val
-is 0) timeout packages in
-.BR LIRC_MODE_MODE2 .
-The behavior of this operation has varied across kernel versions:
-.RS
-.IP \[bu] 3
-Since Linux 5.17:
-timeout packages are always enabled and this ioctl is a no-op.
-.IP \[bu]
-Since Linux 4.16:
-timeout packages are enabled by default.
-Each time the
-.B lirc
-device is opened, the
-.B LIRC_SET_REC_TIMEOUT
-operation can be used to disable (and, if desired, to later re-enable)
-the timeout on the file descriptor.
-.IP \[bu]
-In Linux 4.15 and earlier:
-timeout packages are disabled by default, and enabling them (via
-.BR LIRC_SET_REC_TIMEOUT )
-on any file descriptor associated with the
-.B lirc
-device has the effect of enabling timeouts for all file descriptors
-referring to that device (until timeouts are disabled again).
-.RE
-.TP
-.BR LIRC_SET_REC_CARRIER " (\fIint\fP)"
-Set the upper bound of the receive carrier frequency (Hz).
-See
-.BR LIRC_SET_REC_CARRIER_RANGE .
-.TP
-.BR LIRC_SET_REC_CARRIER_RANGE " (\fIint\fP)"
-Sets the lower bound of the receive carrier frequency (Hz).
-For this to take affect, first set the lower bound using the
-.B LIRC_SET_REC_CARRIER_RANGE
-ioctl, and then the upper bound using the
-.B LIRC_SET_REC_CARRIER
-ioctl.
-.TP
-.BR LIRC_SET_MEASURE_CARRIER_MODE " (\fIint\fP)"
-Enable
-.RI ( val
-is 1) or disable
-.RI ( val
-is 0) the measure mode.
-If enabled, from the next key press on, the driver will send
-.B LIRC_MODE2_FREQUENCY
-packets.
-By default, this should be turned off.
-.TP
-.BR LIRC_GET_REC_RESOLUTION " (\fIvoid\fP)"
-Return the driver resolution (microseconds).
-.TP
-.BR LIRC_SET_TRANSMITTER_MASK " (\fIint\fP)"
-Enable the set of transmitters specified in
-.IR val ,
-which contains a bit mask where each enabled transmitter is a 1.
-The first transmitter is encoded by the least significant bit, and so on.
-When an invalid bit mask is given, for example a bit is set even
-though the device does not have so many transmitters,
-this operation returns the
-number of available transmitters and does nothing otherwise.
-.TP
-.BR LIRC_SET_WIDEBAND_RECEIVER " (\fIint\fP)"
-Some devices are equipped with a special wide band receiver which is
-intended to be used to learn the output of an existing remote.
-This ioctl can be used to enable
-.RI ( val
-equals 1) or disable
-.RI ( val
-equals 0) this functionality.
-This might be useful for devices that otherwise have narrow band
-receivers that prevent them to be used with certain remotes.
-Wide band receivers may also be more precise.
-On the other hand, their disadvantage usually is reduced range of
-reception.
-.IP
-Note: wide band receiver may be implicitly enabled if you enable
-carrier reports.
-In that case, it will be disabled as soon as you disable carrier reports.
-Trying to disable a wide band receiver while carrier reports are active
-will do nothing.
-.\"
-.SH FEATURES
-the
-.B LIRC_GET_FEATURES
-ioctl returns a bit mask describing features of the driver.
-The following bits may be returned in the mask:
-.TP
-.B LIRC_CAN_REC_MODE2
-The driver is capable of receiving using
-.BR LIRC_MODE_MODE2 .
-.TP
-.B LIRC_CAN_REC_SCANCODE
-The driver is capable of receiving using
-.BR LIRC_MODE_SCANCODE .
-.TP
-.B LIRC_CAN_SET_SEND_CARRIER
-The driver supports changing the modulation frequency using
-.BR LIRC_SET_SEND_CARRIER .
-.TP
-.B LIRC_CAN_SET_SEND_DUTY_CYCLE
-The driver supports changing the duty cycle using
-.BR LIRC_SET_SEND_DUTY_CYCLE .
-.TP
-.B LIRC_CAN_SET_TRANSMITTER_MASK
-The driver supports changing the active transmitter(s) using
-.BR LIRC_SET_TRANSMITTER_MASK .
-.TP
-.B LIRC_CAN_SET_REC_CARRIER
-The driver supports setting the receive carrier frequency using
-.BR LIRC_SET_REC_CARRIER .
-Any
-.B lirc
-device since the drivers were merged in Linux 2.6.36
-must have
-.B LIRC_CAN_SET_REC_CARRIER_RANGE
-set if
-.B LIRC_CAN_SET_REC_CARRIER
-feature is set.
-.TP
-.B LIRC_CAN_SET_REC_CARRIER_RANGE
-The driver supports
-.BR LIRC_SET_REC_CARRIER_RANGE .
-The lower bound of the carrier must first be set using the
-.B LIRC_SET_REC_CARRIER_RANGE
-ioctl, before using the
-.B LIRC_SET_REC_CARRIER
-ioctl to set the upper bound.
-.TP
-.B LIRC_CAN_GET_REC_RESOLUTION
-The driver supports
-.BR LIRC_GET_REC_RESOLUTION .
-.TP
-.B LIRC_CAN_SET_REC_TIMEOUT
-The driver supports
-.BR LIRC_SET_REC_TIMEOUT .
-.TP
-.B LIRC_CAN_MEASURE_CARRIER
-The driver supports measuring of the modulation frequency using
-.BR LIRC_SET_MEASURE_CARRIER_MODE .
-.TP
-.B LIRC_CAN_USE_WIDEBAND_RECEIVER
-The driver supports learning mode using
-.BR LIRC_SET_WIDEBAND_RECEIVER .
-.TP
-.B LIRC_CAN_SEND_PULSE
-The driver supports sending using
-.B LIRC_MODE_PULSE
-or
-.B LIRC_MODE_SCANCODE
-.\"
-.SH BUGS
-Using these devices requires the kernel source header file
-.IR lirc.h .
-This file is not available before Linux 4.6.
-Users of older kernels could use the file bundled in
-.UR http://www.lirc.org
-.UE .
-.\"
-.SH SEE ALSO
-\fBir\-ctl\fP(1), \fBlircd\fP(8),\ \fBbpf\fP(2)
-.P
-.UR https://www.kernel.org/\:doc/\:html/\:latest/\:userspace\-api/\:media/\:rc/\:lirc\-dev.html
-.UE