[PATCH] cpukit: Add nxp-sc16is752 serial device driver

[Sebastian Huber]

Hello Joel,

----- Joel Sherrill <joel.sherrill at gmail.com> schrieb:
> Sebastian,
> 
> This is yet another style of serial port driver in recent history and
> the software tax hasn't been paid on the last round of changes.

this is not a new style of serial port drivers.  It uses the new Termios device driver model which I changed in the last patch set to use IMFS generic nodes.  This particular serial device (NXP SC16IS752) is attached via an I2C or SPI bus.  So, this is highly board/application specific.  Adding such a device to a particular BSP would end up in a configuration nightmare.

> Merging this will result in three different styles of serial port drivers
> by my count.
> 
> I am not opposed to improvement but this is rapidly heading
> down the "old vs new PowerPC interrupt" path and that sucked
> for years.

With the recent change for the new Termios device driver model its easier to move the existing console drivers, since there is no need to maintain major/minor numbers anymore.  The drawback is that you have to use IMFS as the base file system.  However, its just a matter of doing it to strip down the IMFS to have similar size demands than the current devfs.

> 
> --joel
> 
> 
> On Mon, Sep 19, 2016 at 8:57 AM, Gedare Bloom <gedare at rtems.org> wrote:
> 
> > It will be good to have some documentation (BSP/driver manual) about
> > how to write these kind of termios drivers. Usually without it we will
> > see someone just copy-paste this one and modify until they get it
> > right... So lacking a plain english doc, this "first" implementation
> > should provide enough comments to make it easy to copy-paste-modify.
> >
> > On Mon, Sep 19, 2016 at 4:11 AM, Sebastian Huber
> > <sebastian.huber at embedded-brains.de> wrote:
> > > Please note that this is the first Termios device driver that is
> > independent
> > > of a BSP, CPU architecture and console driver. It is currently work in
> > > progress and lacks support for interrupts. We will add this probably in
> > one
> > > or two weeks.
> > >
> > > --
> > > Sebastian Huber, embedded brains GmbH
> > >
> > > Address : Dornierstr. 4, D-82178 Puchheim, Germany
> > > Phone   : +49 89 189 47 41-16
> > > Fax     : +49 89 189 47 41-09
> > > E-Mail  : sebastian.huber at embedded-brains.de
> > > PGP     : Public key available on request.
> > >
> > > Diese Nachricht ist keine geschäftliche Mitteilung im Sinne des EHUG.
> > >
> > >
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-- 
Sebastian Huber, embedded brains GmbH

Address : Dornierstr. 4, D-82178 Puchheim, Germany
Phone   : +49 89 189 47 41-16
Fax     : +49 89 189 47 41-09
E-Mail  : sebastian.huber at embedded-brains.de
PGP     : Public key available on request.

Diese Nachricht ist keine geschäftliche Mitteilung im Sinne des EHUG.