[RFC] possible removal of omap-serial

[balbi@ti.com (Felipe Balbi)]

On Thu, Mar 20, 2014 at 08:35:57PM -0500, Felipe Balbi wrote:
> Hi,
> 
> On Thu, Mar 20, 2014 at 05:12:28PM -0700, Greg KH wrote:
> > On Thu, Mar 20, 2014 at 06:52:10PM -0500, Felipe Balbi wrote:
> > > Hi folks,
> > > 
> > > I've been toying with the idea of removing
> > > drivers/tty/serial/omap-serial.c since that's, to put it bluntly, an
> > > ungly copy of 8250 driver.
> > > 
> > > The original concern was wrt suspend/resume but I think it'd be a far
> > > better approach to implement runtime PM in 8250 and write a rather small
> > > 8250-omap.c glue (much like 8250-acorn.c or 8250-dw.c) just to get the
> > > OMAP-specific details out of the way.
> > > 
> > > The question I have is: omap-serial.c calls the serial devnodes ttyO\d,
> > > instead of ttyS\d so removing omap-serial.c would have a direct impact
> > > in userland. I wonder if it's an acceptable "regression" considering
> > > we'd be able to reuse 8250 gaining proper Flow Control support, proper
> > > DMA support, years and years of bug-fixes, etc.
> > 
> > Breaking device node names is a contentious issue for serial ports, I
> > don't think you can do that :(
> 
> would an upstream udev rule creating a symbolic link from ttyO to ttyS
> be enough ?
> 
> I didn't test this yet but I guess this is enough (?)
> 
> KERNEL=="ttyO[0-9]", GROUP="dialout", SYMLINK+="ttyS"

or actually it should be to other way around, ttyS would be the real
device:

KERNEL=="ttyS[0-9]", GROUP="dialout", SYMLINK+="ttyO"

-- 
balbi
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