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Date: Thu, 17 Mar 2011 12:25:10 -0600
From: Grant Likely <grant.likely@secretlab.ca>
To: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: David Daney <ddaney@caviumnetworks.com>, linux-serial@vger.kernel.org,
        gregkh@suse.de, linux-kernel@vger.kernel.org,
        devicetree-discuss@lists.ozlabs.org
Subject: Re: [RFC PATCH 1/2] serial: 8250: Add a notifier chain for driver
 registration.
Message-ID: <20110317182510.GN9597@angua.secretlab.ca>
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On Thu, Mar 17, 2011 at 12:18:49PM +0000, Alan Cox wrote:
> On Wed, 16 Mar 2011 18:26:06 -0700
> David Daney <ddaney@caviumnetworks.com> wrote:
> 
> > The 8250 driver is a bit weird in that in addition to supporting
> > platform devices, extra devices can be added by calling
> > serial8250_register_port().
> > 
> > The problem is that if we call serial8250_register_port() before the
> > driver is initialized Bad Things happen (we dereference NULL
> > pointers).
> > 
> > There doesn't seem to be a general way to know if a driver has been
> > initialized
> 
> I've had a bigger dig into this. I think the correct answer is probably
> "always go via platform devices or similar". That *is* the notifier in
> the kernel of today. serial8250_register_port ultimately should I think
> ultimatly become an internal helper.

+1

Depending on serial8250_register_port() definitely the wrong thing to
do for platform support code.  It would be better to figure out how to
get the dt bits you need into 8250.c or of_serial.c.

g.