From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756730Ab1JYQBU (ORCPT ); Tue, 25 Oct 2011 12:01:20 -0400 Received: from cassiel.sirena.org.uk ([80.68.93.111]:37504 "EHLO cassiel.sirena.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751191Ab1JYQBT (ORCPT ); Tue, 25 Oct 2011 12:01:19 -0400 Date: Tue, 25 Oct 2011 17:01:17 +0100 From: Mark Brown To: Kyle Manna Cc: linux-kernel@vger.kernel.org, Samuel Ortiz , Jorge Eduardo Candelaria , Liam Girdwood Subject: Re: [PATCH v2 1/6] mfd: TPS65910: Handle non-existent devices Message-ID: <20111025160117.GA634@sirena.org.uk> References: <1319475964-10841-1-git-send-email-kyle.manna@fuel7.com> <1319475964-10841-2-git-send-email-kyle.manna@fuel7.com> <20111025071417.GE2919@opensource.wolfsonmicro.com> <4EA6D14D.6060800@fuel7.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4EA6D14D.6060800@fuel7.com> X-Cookie: diplomacy, n: User-Agent: Mutt/1.5.20 (2009-06-14) X-SA-Exim-Connect-IP: X-SA-Exim-Mail-From: broonie@sirena.org.uk X-SA-Exim-Scanned: No (on cassiel.sirena.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Oct 25, 2011 at 10:10:05AM -0500, Kyle Manna wrote: > On 10/25/2011 02:14 AM, Mark Brown wrote: > >Can you check for a known value in any of the registers? > Unfortunately on this chip there aren't any identification or > constant test registers. The only register close is the > JTAGVERNUM_REG and that's will change across silicon revisions. It seems like a more useful implementation would be to have the driver read and display this revision number during boot, this will give you the register readability check and also let us know the device revision which might be useful for diagnostics.