Re: serial8250_init and platform_device

Kumar Gala
2005-01-20T20:29:33Z

Good, I can understand the need to maintain compatibility until we get
ride of SERIAL_PORT_DFNS.

- kumar

On Jan 20, 2005, at 1:38 PM, Russell King wrote:

> On Thu, Jan 20, 2005 at 01:06:55PM -0600, Kumar Gala wrote:
> > Russell,
> >
> > I think this all makes sense to me.  I'm just wondering why we would
> > have a platform device register in a system for 'legacy ISA' when we
> > know the system doesnt have any ports that will fit the category.
> >
> > As you show in example #2 you have
> >
> > .../devices/platform/serial82500
> > .../devices/platform/serial8250
> >
> > why have the 'serial8250' if you know your system doesnt have any
> ports
> > that will exist there?
>
> In this case, it is a placeholder, and needs to be there if you're
> using
> power management.
>
> For instance, you may use setserial on /dev/ttyS2 to reconfigure it
> to an address where you know a serial port is.  Without the
> "serial8250"
> device, it isn't linked into the device model, and therefore doesn't
> receive any power management notifications.
>
> Once the SERIAL_PORT_DFNS are gone, and we have a more modern interface
> than setserial for setting up random ports, this "serial8250" device
> will vanish.
>
> While we're here, you've reminded me about an annoying point about
> platform device naming...
>
> Greg - the name is constructed from "name" + "id num" thusly:
>
>         serial8250
>         serial82500
>         serial82501
>         serial82502
>
> When "name" ends in a number, it gets rather confusing.  Can we have
> an optional delimiter in there when we append the ID number, maybe
> something like a '.' or ':' ?
>
> --
> Russell King
>  Linux kernel    2.6 ARM Linux   - http://www.arm.linux.org.uk/
>  maintainer of:  2.6 PCMCIA      - http://pcmcia.arm.linux.org.uk/
>                  2.6 Serial core