From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753810AbaHTL7K (ORCPT ); Wed, 20 Aug 2014 07:59:10 -0400 Received: from mail-ie0-f179.google.com ([209.85.223.179]:53595 "EHLO mail-ie0-f179.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753793AbaHTL7H (ORCPT ); Wed, 20 Aug 2014 07:59:07 -0400 Date: Wed, 20 Aug 2014 12:59:01 +0100 From: Lee Jones To: Javier Martinez Canillas Cc: Marek Szyprowski , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Samuel Ortiz , Daniel Drake , Tobias Jakobi , Olof Johansson , Bartlomiej Zolnierkiewicz , Krzysztof Kozlowski Subject: Re: [PATCH] mfd: max77686: make interrupts support optional Message-ID: <20140820115901.GJ4266@lee--X1> References: <1408516009-22106-1-git-send-email-m.szyprowski@samsung.com> <20140820081909.GH4266@lee--X1> <53F45C73.1030304@collabora.co.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <53F45C73.1030304@collabora.co.uk> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 20 Aug 2014, Javier Martinez Canillas wrote: > Hello Lee, Marek, > > On 08/20/2014 10:19 AM, Lee Jones wrote: > > On Wed, 20 Aug 2014, Marek Szyprowski wrote: > > > >> Commit 6f1c1e71d93 ("mfd: max77686: Convert to use regmap_irq") broke > >> support for boards, which provide no irq for MAX 77686 PMIC. In such > >> case, not all functions of PMIC are available, but the driver still > >> should at least handle voltage regulators instead of failing to init. > >> This patch restores previous behavior. > >> > >> Signed-off-by: Marek Szyprowski > >> --- > >> Hello, > >> > >> This patch fixes booting issues with recently merged support for > >> Exynos4412 based Odroid X2/U3 boards. See > >> http://www.spinics.net/lists/linux-samsung-soc/msg35773.html > >> thread for more details. > >> > >> Best regards > >> Marek Szyprowski > >> Samsung R&D Institute Poland > > I already gave my opinion about this patch on thread: > > "[PATCH v2 0/4] Add Exynos4412 based Odroid X2 and U2/U3/U3+ support" > > where the issue was reported by Olof but I'll add it here as well for > completeness since I don't know if the same people are cc'ed on both threads. > > Bartlomiej Zolnierkiewicz posted a similar patch [0] before but as I said > on that thread, I'm not sure if is correct to make that DT property > optional. Or rather, if we need to make it optional then we should also > change the Documentation/devicetree/bindings/mfd/max77686.txt that list > "interrupts" DT property as required. > > It's true that before converting the max77686 to use the regmap irq API, > the driver was loose on that regard but max77686_irq_init() in > max77686-irq.c was returning -ENODEV when the IRQ was not provided and > that error code was not checked in max77686_i2c_probe() (which was a bug > IMHO). > > More importantly I wonder if a design where a IRQ line is not connected to > the max77686 PMIC makes even sense. If such a design is possible then the > "interrupt" property should be made optional but if not then I think that > the driver should fail to probe in that case. Yes, it is a regression but > the Odroid DTS was not following the DT binding and was just lucky that > the driver was not checking the required DT properties. > > Daniel Drake posted the correct fix for the Odroid DTS [1]. So I tend to > say that Daniel's fix should be added as a -rc fix and we should keep both > the max77686 driver and its DT binding as it is now but as I said, if from > a hardware point of view makes sense to leave that line unconnected then I > don't oppose to this change. I wasn't aware that this had already been discussed. FWIW, I agree with everything you just said, so unless someone insists that the device can be functional without an IRQ line, I'm going to shelve (not accept) this patch. > [0]: https://lkml.org/lkml/2014/8/7/374 > [1]: > http://lists.infradead.org/pipermail/linux-arm-kernel/2014-July/272869.html -- Lee Jones Linaro STMicroelectronics Landing Team Lead Linaro.org │ Open source software for ARM SoCs Follow Linaro: Facebook | Twitter | Blog