Date: Tue, 23 Nov 2010 23:03:59 +0000
From: Alan Cox <alan@lxorguk.ukuu.org.uk>
To: Timur Tabi <timur@freescale.com>
Cc: Greg KH <gregkh@suse.de>, Arnd Bergmann <arnd@arndb.de>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Scott Wood <scottwood@freescale.com>,
        Stuart Yoder <stuart.yoder@freescale.com>
Subject: Re: How do I choose an arbitrary minor number for my tty device?
Message-ID: <20101123230359.3c805e2e@lxorguk.ukuu.org.uk>
In-Reply-To: <4CEBF668.2080708@freescale.com>
References: <20101118163321.GA2723@suse.de>
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	<4CE55ACB.80207@freescale.com>
	<20101118171856.GA4283@suse.de>
	<4CE5647F.5000203@freescale.com>
	<20101118175832.GA4931@suse.de>
	<4CE58005.7040308@freescale.com>
	<20101118200230.GA25715@suse.de>
	<4CE58736.4090703@freescale.com>
	<20101118201035.GA26287@suse.de>
	<4CE58FE5.3010502@freescale.com>
	<20101118205647.677404ec@lxorguk.ukuu.org.uk>
	<4CEA9B00.1000804@freescale.com>
	<20101123135621.5d100e81@lxorguk.ukuu.org.uk>
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> Are you talking about this:
> 
> static struct tty_driver *ehv_bc_console_device(struct console *co, int *index)
> {
> 	*index = co->index;
> 
> 	return ehv_bc_driver;
> }

Yes.

> I never really understood this function, but almost everyone does the same
> thing, and it seems to work for me.  Looking at console_device(), it appears
> that all of the xxx_console_device functions are called in order until one of
> them returns non-NULL.

*index is the minor number to use - so you can return whichever minor
matches your primary interface

> > I suspect in your case you probably want to attach the primary byte
> > channel to minor 0 in the driver (and reserve it for that), or some
> > similar rule.
> 
> Yes, that's a good idea.  It does simplify things a lot.

It's probably the cleanest and simplest solution and it fits the
"natural" order of things.
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