1 files changed, 46 insertions, 7 deletions

diff --git a/Documentation/media/uapi/rc/lirc-dev-intro.rst b/Documentation/media/uapi/rc/lirc-dev-intro.rst
index ef97e40..d1936ee 100644
--- a/Documentation/media/uapi/rc/lirc-dev-intro.rst
+++ b/Documentation/media/uapi/rc/lirc-dev-intro.rst
@@ -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.