Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755819AbbEUT6K (ORCPT ); Thu, 21 May 2015 15:58:10 -0400 Received: from mail-wi0-f175.google.com ([209.85.212.175]:37562 "EHLO mail-wi0-f175.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932160AbbEUT56 convert rfc822-to-8bit (ORCPT ); Thu, 21 May 2015 15:57:58 -0400 MIME-Version: 1.0 In-Reply-To: <555E1CC4.9090605@suse.de> References: <1431158038-3813-1-git-send-email-mcoquelin.stm32@gmail.com> <1431158038-3813-8-git-send-email-mcoquelin.stm32@gmail.com> <555D1C7D.1060205@suse.de> <555E1CC4.9090605@suse.de> Date: Thu, 21 May 2015 21:57:56 +0200 Message-ID: Subject: Re: [PATCH v8 07/16] drivers: reset: Add STM32 reset driver From: Maxime Coquelin To: =?UTF-8?Q?Andreas_F=C3=A4rber?= , Kamil Lulko , Rob Herring , Arnd Bergmann Cc: Mark Rutland , "linux-doc@vger.kernel.org" , Linus Walleij , Will Deacon , Stefan Agner , Nikolay Borisov , Peter Meerwald , Lee Jones , Linux-Arch , Daniel Thompson , Russell King , Pawel Moll , Jonathan Corbet , Jiri Slaby , Daniel Lezcano , Chanwoo Choi , Andy Shevchenko , Antti Palosaari , Geert Uytterhoeven , "linux-serial@vger.kernel.org" , =?UTF-8?Q?Uwe_Kleine=2DK=C3=B6nig?= , "devicetree@vger.kernel.org" , Kees Cook , Mauro Carvalho Chehab , Rusty Russell , "linux-gpio@vger.kernel.org" , Kumar Gala , Thomas Gleixner , Ian Campbell , Nicolae Rosia , "linux-arm-kernel@lists.infradead.org" , Michal Marek , Paul Bolle , Peter Hurley , "linux-api@vger.kernel.org" , "linux-kernel@vger.kernel.org" , Philipp Zabel , Greg Kroah-Hartman , Joe Perches , Tejun Heo , Andrew Morton , "David S. Miller" , Vladimir Zapolskiy Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2588 Lines: 63 2015-05-21 19:58 GMT+02:00 Andreas Färber : > Am 21.05.2015 um 09:46 schrieb Maxime Coquelin: >> 2015-05-21 1:45 GMT+02:00 Andreas Färber : >>> Am 09.05.2015 um 09:53 schrieb Maxime Coquelin: >>>> +static const struct of_device_id stm32_reset_dt_ids[] = { >>>> + { .compatible = "st,stm32-rcc", }, >>>> + { /* sentinel */ }, >>>> +}; >>>> +MODULE_DEVICE_TABLE(of, sstm32_reset_dt_ids); >>> >>> Typo. >> >> Indeed, thanks for pointing this out. >> >>> >>> IIUC the timer depends on the reset controller, so it must be built in >>> anyway, and that's what's enforced in the Makefile above. Drop the line? >>> >> >> Agree it must be built-in. >> I will fix that in next version. > > Actually, I've updated a timer implementation of mine to invoke a reset > controller similar to how you do in the STM32 clocksource patch, but no > reset controller is getting returned. > > It seems to me, you are working around that by simply ignoring the error > in the timer code and not doing a reset then, so the STM32 timer does in > fact _not_ depend on the reset controller? What happened to your efforts > of making the reset controller usable for the timer? In my case, my > timer is originally in reset state and needs to be deasserted, so I > can't just ignore it. Indeed, I made the reset optionnal in the clocksource patch since v3. Rob and Arnd said a lot of platform relies on such things are done by the bootloader [0]. I decided to deassert timers reset at bootloader stage, and make it optionnal in clocksource driver. I made it optionnal in case we decide one day to move reset initialization before timer are initialized. Note that for now, I still use your bootloader. I have done the changes to reset the timers in the afboot-stm32. That's the reason why I asked you under which licence it is delivered few months ago. I can share you the patch if you want, even if I understand it is more about the concept that you are reluctant. On my side, I plan to move to U-Boot soon, as Kamil Lulko added STM32 support in mainline [1]. In case of U-Boot, the timer reset should be de-asserted when jumping into the Kernel, as Rob mentionned [0]. Kind regards, Maxime [0]: https://lkml.org/lkml/2015/3/10/737 [1]: http://u-boot.10912.n7.nabble.com/PATCH-v2-stm32f4-fix-serial-output-td212812.html -- 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/