Re: [PATCH 4/4] serial: sccnxp: Add DT support

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

On Fri, Aug 02, 2013 at 10:27:55AM +0400, Alexander Shiyan wrote:
> On Thu, 1 Aug 2013 15:14:20 +0100
> Mark Rutland <mark.rutland@arm.com> wrote:
> 
> > On Thu, Aug 01, 2013 at 11:53:43AM +0100, Alexander Shiyan wrote:
> > > > On Wed, Jul 31, 2013 at 11:55:45AM +0100, Alexander Shiyan wrote:
> > > > > Add DT support to the SCCNCP serial driver.
> > > > > 
> > > > > Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
> > > > > ---
> > > > >  .../bindings/tty/serial/sccnxp-serial.txt          | 53 ++++++++++++++++++++++
> > > > >  drivers/tty/serial/sccnxp.c                        | 46 +++++++++++++++----
> > > > >  include/linux/platform_data/serial-sccnxp.h        |  6 +--
> > > > >  3 files changed, 93 insertions(+), 12 deletions(-)
> > > > >  create mode 100644 Documentation/devicetree/bindings/tty/serial/sccnxp-serial.txt
> > > > > 
> > > > > diff --git a/Documentation/devicetree/bindings/tty/serial/sccnxp-serial.txt b/Documentation/devicetree/bindings/tty/serial/sccnxp-serial.txt
> > > [...]
> > > > > +Optional properties:
> > > > > +- clocks: Phandle to input clock. If omitted, default IC frequency will be
> > > > > +  used instead.
> > 
> > Come to think of it, what is "default IC frequency" likely to be, and
> > how does it influence the usable baud rates?
> > 
> > > > > +- poll-interval: Poll interval time in nanoseconds.
> > > > 
> > > > Is there any reason this needs to be described at all? Is this interval
> > > > a minimum/maximum bound required for some reason, or just a sensible
> > > > value?
> > > > 
> > > > This feels like driver configuration than hardware description.
> > > 
> > > This is a exact value for driver in the polling mode.
> > 
> > That certainly sounds like driver configuration ;)
> > 
> > > Depends on desired response time and/or desired UART baudrate.
> > 
> > If this depends on the desired baud rate, how does this interact with
> > dynamically changing the baud rate later -- surely you may need to have
> > different polling rates for high and low baud rates?
> 
> I will change it to automatically calculate a reasonable value for polling.
> 
> [...]
> 
> Greg, please remove this part of patch from tty-tree.

Now removed.