On Mon, May 17, 2010 at 11:48:15PM +0100, wdev@xxxxxxxxxxx wrote:
> The decoding routine is based on own reverse-engineering. It seems to
> recognize all the messages that MPD16 sends during normal operation
> (that is, via standard MIDI messages).
>
> Configuration (changing pad sensitivity, slider controller and MIDI
> notes) is not supported in this version.
>
> Signed-off-by: Krzysztof Foltman <wdev@xxxxxxxxxxx>
>
> diff --git a/sound/usb/midi.c b/sound/usb/midi.c
> index 2c1558c..57d642a 100644
> --- a/sound/usb/midi.c
> +++ b/sound/usb/midi.c
> @@ -645,6 +645,34 @@ static struct usb_protocol_ops snd_usbmidi_cme_ops = {
> };
>
> /*
> + * AKAI MPD16 protocol: one or more chunks consisting of first byte of
> + * (0x20 | msg_len) and then a MIDI message (msg_len bytes long)
> + *
> + * Messages sent:
> + * 21 FE (active sense)
> + * 23 90 xx xx (note on)
> + * 23 Ax xx xx (polyphonic pressure)
> + * 23 Bx xx xx (control change)
> + */
> +static void snd_usbmidi_akai_input(struct snd_usb_midi_in_endpoint *ep,
> + uint8_t *buffer, int buffer_length)
> +{
> + unsigned int pos = 0;
> + while (pos < (unsigned)buffer_length && (buffer[pos] & 0xF8) == 0x20)
> + {
> + int msg_len = buffer[pos] & 0x0f;
> + snd_usbmidi_input_data(ep, 0, &buffer[pos + 1], msg_len);
> + pos += 1 + msg_len;
> + }
> +}
Just a minor coding style flaw here for the curly brackets. See
Documentation/CodingStyle or let scripts/checkpatch.pl annoy you :)
FWIW, I think the block above could also be a for-loop, but that's
certainly a matter of taste.
Thanks,
Daniel
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