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Diffstat (limited to 'Documentation/media/uapi/rc/lirc-write.rst')
| -rw-r--r-- | Documentation/media/uapi/rc/lirc-write.rst | 19 |
1 files changed, 15 insertions, 4 deletions
diff --git a/Documentation/media/uapi/rc/lirc-write.rst b/Documentation/media/uapi/rc/lirc-write.rst index 2aad0fef4a5b..d4566b0a2015 100644 --- a/Documentation/media/uapi/rc/lirc-write.rst +++ b/Documentation/media/uapi/rc/lirc-write.rst @@ -42,21 +42,32 @@ Description referenced by the file descriptor ``fd`` from the buffer starting at ``buf``. -The exact format of the data depends on what mode a driver uses, use -:ref:`lirc_get_features` to get the supported mode. +The exact format of the data depends on what mode a driver is in, use +:ref:`lirc_get_features` to get the supported modes and use +:ref:`lirc_set_send_mode` set the mode. When in :ref:`LIRC_MODE_PULSE <lirc-mode-PULSE>` mode, the data written to the chardev 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, therefore, the data must always include an uneven number of -samples. The write function must block until the data has been transmitted +samples. The write function blocks until the data has been transmitted by the hardware. If more data is provided than the hardware can send, the driver returns ``EINVAL``. +When in :ref:`LIRC_MODE_SCANCODE <lirc-mode-scancode>` mode, one +``struct lirc_scancode`` must be written to the chardev at a time, else +``EINVAL`` is returned. Set the desired scancode in the ``scancode`` member, +and the protocol in the :c:type:`rc_proto`: member. All other members must be +set to 0, else ``EINVAL`` is returned. If there is no protocol encoder +for the protocol or the scancode is not valid for the specified protocol, +``EINVAL`` is returned. The write function blocks until the scancode +is transmitted by the hardware. + + Return Value ============ -On success, the number of bytes read is returned. It is not an error if +On success, the number of bytes written is returned. It is not an error if this number is smaller than the number of bytes requested, or the amount of data required for one frame. On error, -1 is returned, and the ``errno`` variable is set appropriately. The generic error codes are described at the |