lkml.org 
[lkml]   [2011]   [Apr]   [19]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRE: [PATCH] tty/serial: add support for Xilinx PS UART
Date
From
> -----Original Message-----
> From: Greg KH [mailto:greg@kroah.com]
> Sent: Tuesday, April 19, 2011 5:22 PM
> To: John Linn
> Cc: Alan Cox; linux-kernel@vger.kernel.org; linux-
> serial@vger.kernel.org
> Subject: Re: [PATCH] tty/serial: add support for Xilinx PS UART
>
> On Tue, Apr 19, 2011 at 04:22:00PM -0600, John Linn wrote:
> > > -----Original Message-----
> > > From: Alan Cox [mailto:alan@lxorguk.ukuu.org.uk]
> > > Sent: Tuesday, April 19, 2011 3:16 PM
> > > To: John Linn
> > > Cc: linux-kernel@vger.kernel.org; linux-serial@vger.kernel.org
> > > Subject: Re: [PATCH] tty/serial: add support for Xilinx PS UART
> > >
> > > On Tue, 19 Apr 2011 14:14:52 -0600
> > > John Linn <john.linn@xilinx.com> wrote:
> > >
> > > > The Xilinx PS Uart is used on the new ARM based SoC. This
> > > > UART is not compatible with others such that a seperate
> > > > driver is required.
> > >
> > > Joyous. I wish people would standardise.
> > >
> > > > + 213 = /dev/ttyPS0 Xilinx PS serial
port 0
> > > > + 214 = /dev/ttyPS1 Xilinx PS serial
port 1
> > > > + 215 = /dev/ttyPS2 Xilinx PS serial
port 2
> > > > + 216 = /dev/ttyPS3 Xilinx PS serial
port 3
> > >
> > > Is there a specific reason you need fixed minor numbers ? If not
> > please
> > > use a dynamic range and keep Linus happy.
> >
> > Hi Alan,
> >
> > I hope you don't mind me asking a bit more to better understand.
> Here's
> > my
> > concerns (maybe not valid).
> >
> > It seems like since this is a console it can get hard to debug with
> > dynamic
> > nodes for this driver.
> >
> > This driver is for an embedded device where we don't want to require
> > udev
> > or mdev to assign nodes.
>
> Why not use devtmpfs? There's no need to use udev or mdev at all.
>

Hi Greg,

Reading up on it a bit as I'm not an expert on it (like you).
It's not clear to me what the device driver uses for it's major/minor in
this case.

Maybe it doesn't matter, the driver can use ttyS0 and then it gets
deleted
later if you want to change it.

The only reason we didn't just use ttyS0 was that it's not a 8250 really
and
since we have are an FPGA people can add real 8250s in soft logic and
then
the system would get confusing.

Thanks,
John

> thanks,
>
> greg k-h


This email and any attachments are intended for the sole use of the named recipient(s) and contain(s) confidential information that may be proprietary, privileged or copyrighted under applicable law. If you are not the intended recipient, do not read, copy, or forward this email message or any attachments. Delete this email message and any attachments immediately.




\
 
 \ /
  Last update: 2011-04-20 01:41    [W:1.347 / U:0.116 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site