Subject: Re: How do I choose an arbitrary minor number for my tty device?
From: Michael Ellerman <michael@ellerman.id.au>
Reply-To: michael@ellerman.id.au
To: Scott Wood <scottwood@freescale.com>
Cc: Timur Tabi <timur@freescale.com>, Greg KH <gregkh@suse.de>,
        Arnd Bergmann <arnd@arndb.de>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Stuart Yoder <stuart.yoder@freescale.com>
In-Reply-To: <20101118121356.3491da72@udp111988uds.am.freescale.net>
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Date: Wed, 24 Nov 2010 21:23:47 +1100
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On Thu, 2010-11-18 at 12:13 -0600, Scott Wood wrote:
> On Thu, 18 Nov 2010 11:42:21 -0600
> Timur Tabi <timur@freescale.com> wrote:
>=20
> > Scott Wood wrote:

> > > We should add a proper bus for the "handles" node.  Then sysfs should
> > > show the link between the tty device and a device tree node -- which =
is
> > > really what we're after, the handle is just a means to that end.
> >=20
> > How exactly do I do that?
>=20
> Pass the platform device pointer to tty_register_device.
>=20
> Then, in the sysfs node, "driver" should be a symlink to
> another sysfs node whose path looks lind of like an OF path.
>=20
> Unfortunately, it's not an exact match, and the fact that reg doesn't
> translate to a physical address means that AFAICT you'll currently get
> something like "byte-channel.nnn", where "nnn" is an arbitrary
> kernel-assigned number.

Can you not use device_rename() ?

> It would be nice if platform devices that are created from device tree
> nodes included a link to the corresponding /proc/device-tree node in
> their sysfs node.

It's not a link, but the OF path is in devspec, so you can work it out
fairly easily.

cheers


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