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From: Kumar Gala <kumar.gala@freescale.com>
To: "Russell King" <rmk+lkml@arm.linux.org.uk>
Cc: "Linux Kernel list" <linux-kernel@vger.kernel.org>,
	"Greg KH" <greg@kroah.com>
Subject: Re: serial8250_init and platform_device
Date: Thu, 20 Jan 2005 14:26:30 -0600	[thread overview]
Message-ID: <91CB879A-6B21-11D9-BD44-000393DBC2E8@freescale.com> (raw)
In-Reply-To: <20050120193845.H13242@flint.arm.linux.org.uk>

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


      parent reply	other threads:[~2005-01-20 20:29 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2005-01-20  7:14 serial8250_init and platform_device Kumar Gala
2005-01-20 11:43 ` Russell King
2005-01-20 15:23   ` Kumar Gala
2005-01-20 15:44     ` Russell King
2005-01-20 19:06       ` Kumar Gala
2005-01-20 19:38         ` Russell King
2005-01-20 19:50           ` Greg KH
2005-01-20 20:10             ` Russell King
2005-01-20 20:25               ` Kumar Gala
2005-02-01  8:41               ` Greg KH
2005-01-20 20:26           ` Kumar Gala [this message]

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