Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752849AbbGUIjf (ORCPT ); Tue, 21 Jul 2015 04:39:35 -0400 Received: from down.free-electrons.com ([37.187.137.238]:45320 "EHLO mail.free-electrons.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752157AbbGUIjI (ORCPT ); Tue, 21 Jul 2015 04:39:08 -0400 Date: Tue, 21 Jul 2015 10:39:05 +0200 From: Alexandre Belloni To: "Opensource [Steve Twiss]" Cc: Lee Jones , Alessandro Zummo , DEVICETREE , LINUXINPUT , LINUXKERNEL , RTCLINUX , David Dajun Chen , Ian Campbell , Kumar Gala , Mark Rutland , Pawel Moll , Rob Herring , Samuel Ortiz , Support Opensource Subject: Re: [PATCH RFC V1 2/3] rtc: da9063: Add DA9062 RTC capability to DA9063 RTC driver Message-ID: <20150721083905.GB2853@piout.net> References: <20150717234525.GI3487@piout.net> <6ED8E3B22081A4459DAC7699F3695FB7014B253DC9@SW-EX-MBX02.diasemi.com> <20150720215045.GO15539@piout.net> <6ED8E3B22081A4459DAC7699F3695FB7014B253FD1@SW-EX-MBX02.diasemi.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <6ED8E3B22081A4459DAC7699F3695FB7014B253FD1@SW-EX-MBX02.diasemi.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2226 Lines: 55 Hi, On 21/07/2015 at 08:05:32 +0000, Opensource [Steve Twiss] wrote : > > > > > + > > > > > + rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL); > > > > > + if (!rtc) > > > > > + return -ENOMEM; > > > > > + > > > > > + if (strncmp(match->name, "dlg,da9063-rtc", 14) == 0) { > > > > > + struct da9063 *chip = dev_get_drvdata(pdev->dev.parent); > > > > > + > > > > > + if (chip->variant_code == PMIC_DA9063_AD) > > > > > + rtc->config = &da9063_ad_regs; > > > > > + } else > > > > > + rtc->config = match->data; > > > > > > > > You must not do that. > > > > You should add a new compatible and change the of_compatible string of > > > > the mfd_cell in drivers/mfd/da9063-core.c onc you know the variant. > > > > > > I can check for a binary comparison against the address of the > > > static const struct of_device_id da9063_compatible_reg_id_table[] = {} > > > entry for DA9063. > > > > You also must not compare pointers that way. You can use > > of_device_is_compatible(). > > > > > The DA9063 driver already associates "dlg,da9063-rtc" with both BB and AD > > > register maps. I think that altering the string at this point would break backwards > > > compatibility in the device tree for the DA9063. > > > > I'm not fond of the backward compatibility exactly for that kind of > > issue. The proper way to handle it is to have tow different compatible > > strings because obviously, the BB and AD variants are not compatible. > > I think I understand what you are saying about modifying the mfd_cell in the > DA9063 core driver at run-time so that it changes the of_compatible string to [something like] > "dlg,da9063-ad-rtc". That way the RTC driver can be probed using the correct > string. > > Ok, I think I see now .. I'll make a patch v2 and send it soon. > This is not needed if you simply change your strncmp with of_device_is_compatible -- Alexandre Belloni, Free Electrons Embedded Linux, Kernel and Android engineering http://free-electrons.com -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/