On Tue, 2014-10-21 at 09:20 +0200, Daniel Mack wrote:
Hi,
Thanks for sharing this!
On 10/21/2014 01:40 AM, Kim Taylor wrote:
I've written a driver for raw MIDI using the PL011. It is obviously based on the snd-serial-u16550 module, with a couple of improvements:
I've implemented a drain() callback.
I've also implemented a half duplex mode based on a timer callback
which was necessary for reliable communication with my eMagic Unitor 8 hardware. (Testing with a serial link to other hardware shows that the full duplex mode is also working.)
So I guess you could patch the existing driver to make it work for your use case, right? I haven't looked at the code in detail, but from what you describe, that should be possible.
I'm not sure about that. As it uses a different UART chip, there is a new probe() function, it uses memory mapped I/O, instead of i386 inb/outb, it gathers information from the ARM AMBA bus...
The only things that would remain unchanged are the output_trigger() and output_write() functions. One possibility might be to abstract out all read/write operations using function pointers, however, I believe that the new driver is different enough to constitute a new module.
Or maybe there should be a third module (for example snd-serial-core, containing any common functions, exporting them to both snd-serial-u16550 and snd-serial-pl011?
It can be found here: https://github.com/kmtaylor/rpi_patches/blob/master/serial-pl011.c
If you think it should be included in the ALSA repository, please let me know what to do next.
Clone this repository:
git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound.git
and integrate your changes there, then send patches to this mailing list. Especially if you're doing it for the first time, Documentation/SubmittingPatches is a good read to omit some typical pitfalls.
Will do. Thanks.