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From: Clemens Ladisch <clemens@ladisch.de>
To: Francesco Lavra <francescolavra.fl@gmail.com>,
	alsa-devel@alsa-project.org
Subject: Re: MIDI port using UART interface
Date: Wed, 23 Sep 2015 20:14:22 +0200	[thread overview]
Message-ID: <5602EBFE.5000203@ladisch.de> (raw)
In-Reply-To: <55FD6494.8030208@gmail.com>

Francesco Lavra wrote:
> I would have expected to find a generic MIDI<->UART adapter layer in
> the kernel that bridges the ALSA MIDI interface with UART drivers and
> allows to operate UARTs as MIDI ports. But apparently there is no such
> generic adapter, the closest driver I found is for the UART 16550 but
> this is specific to a type of UART controller different from the one
> in the platform I'm using (which is i.MX6).

In the Good Old Times™, all UARTs were 16550 or MPU-401 compatible.

> So how would you approach the task of writing a MIDI driver that uses
> UART behind the scenes? Am I correct in assuming that I have to use
> the RawMIDI interface (as the UART 16550 driver does) to make my MIDI
> port available to ALSA applications? Or is there a better alternative?

The kernel-internal serial port interfaces are designed to be able to
run a console.

The easiest way would be a userspace daemon that bridges between some
/dev/tty* and the ALSA sequencer.
See <http://www.alsa-project.org/~clemens/usbmidid/usbmidid.c> for an
example that uses some other device.


Regards,
Clemens
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  reply	other threads:[~2015-09-23 18:14 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-09-19 13:35 MIDI port using UART interface Francesco Lavra
2015-09-23 18:14 ` Clemens Ladisch [this message]
2015-09-24  6:58   ` Francesco Lavra

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