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[media] lirc: document lirc modes better

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LIRC_MODE_MODE2 and LIRC_MODE_LIRCCODE were not covered at all.

Signed-off-by: Sean Young <sean@mess.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
This commit is contained in:
Sean Young
2017-02-08 15:10:30 -02:00
committed by Mauro Carvalho Chehab
parent 5cd6522c5b
commit a8b875a549
10 changed files with 81 additions and 35 deletions
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53
Documentation/media/uapi/rc/lirc-dev-intro.rst
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@@ -27,6 +27,8 @@ What you should see for a chardev:
$ ls -l /dev/lirc*
crw-rw---- 1 root root 248, 0 Jul 2 22:20 /dev/lirc0
.. _lirc_modes:
**********
LIRC modes
**********
@@ -38,25 +40,62 @@ on the following table.
``LIRC_MODE_MODE2``
The driver returns a sequence of pulse and space codes to userspace.
The driver returns a sequence of pulse and space codes to userspace,
as a series of u32 values.
This mode is used only for IR receive.
The upper 8 bits determine the packet type, and the lower 24 bits
the payload. Use ``LIRC_VALUE()`` macro to get the payload, and
the macro ``LIRC_MODE2()`` will give you the type, which
is one of:
``LIRC_MODE2_PULSE``
Signifies the presence of IR in microseconds.
``LIRC_MODE2_SPACE``
Signifies absence of IR in microseconds.
``LIRC_MODE2_FREQUENCY``
If measurement of the carrier frequency was enabled with
:ref:`lirc_set_measure_carrier_mode` then this packet gives you
the carrier frequency in Hertz.
``LIRC_MODE2_TIMEOUT``
If timeout reports are enabled with
:ref:`lirc_set_rec_timeout_reports`, when the timeout set with
:ref:`lirc_set_rec_timeout` expires due to no IR being detected,
this packet will be sent, with the number of microseconds with
no IR.
.. _lirc-mode-lirccode:
``LIRC_MODE_LIRCCODE``
The IR signal is decoded internally by the receiver. The LIRC interface
returns the scancode as an integer value. This is the usual mode used
by several TV media cards.
This mode can be used for IR receive and send.
This mode is used only for IR receive.
The IR signal is decoded internally by the receiver, or encoded by the
transmitter. The LIRC interface represents the scancode as byte string,
which might not be a u32, it can be any length. The value is entirely
driver dependent. This mode is used by some older lirc drivers.
The length of each code depends on the driver, which can be retrieved
with :ref:`lirc_get_length`. This length is used both
for transmitting and receiving IR.
.. _lirc-mode-pulse:
``LIRC_MODE_PULSE``
On puse mode, a sequence of pulse/space integer values are written to the
lirc device using :Ref:`lirc-write`.
In pulse mode, a sequence of pulse/space integer values are written to the
lirc device using :ref:`lirc-write`.
The values are alternating pulse and space lengths, in microseconds. The
first and last entry must be a pulse, so there must be an odd number
of entries.
This mode is used only for IR send.