From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id D4E15C433FE for ; Thu, 17 Mar 2022 17:16:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236816AbiCQRRk (ORCPT ); Thu, 17 Mar 2022 13:17:40 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33062 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230168AbiCQRRh (ORCPT ); Thu, 17 Mar 2022 13:17:37 -0400 Received: from relay4-d.mail.gandi.net (relay4-d.mail.gandi.net [217.70.183.196]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1070BA6E13; Thu, 17 Mar 2022 10:16:19 -0700 (PDT) Received: (Authenticated sender: alexandre.belloni@bootlin.com) by mail.gandi.net (Postfix) with ESMTPSA id 54D54E000B; Thu, 17 Mar 2022 17:16:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bootlin.com; s=gm1; t=1647537378; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=fccZaLU3e9ufDI4tRZPJop/s9Lv4MUlUjsAiY2kUdW0=; b=PDeZ0bkwhoWzeOQnqKILcYTvx76vPbtd4o51rDK58u8n9MfsPtindNsaV9YhI8jUr5vZ0d sMljGWimoHOkt3jqGEIVotBuFyIwrvyiq6wxPf2DDU1p0ao52g7eDfpFWJt33QDEFfICqn OjQ70FgTyCj1dPhKbP9t1pbxGZQ/sWDGkOyLfteDe8WYsDXoM/Qcj7GqFj4VeUXWQtFBCd kSO/PYrkvIZr8Q9NLAGkp8jLTjTvLSfptgBD1QeAVl+teVovbmiks1jvYs+ZRJpmulG2XF kk/u6wnO1ic0MkYPrUQg/hsdulXT5A/ngQLresVustUZdrY2vYU9RkLFq2CqjA== Date: Thu, 17 Mar 2022 18:16:17 +0100 From: Alexandre Belloni To: Hugo Villeneuve Cc: Alessandro Zummo , linux-rtc@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 11/29] rtc: pcf2127: set RTC_FEATURE_ALARM_RES_2S Message-ID: References: <20220309162301.61679-1-alexandre.belloni@bootlin.com> <20220309162301.61679-11-alexandre.belloni@bootlin.com> <20220310110918.41a681474f5a0e11abdedc39@hugovil.com> <20220317112820.7617d0d68f50f24ad0c3739e@hugovil.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220317112820.7617d0d68f50f24ad0c3739e@hugovil.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, On 17/03/2022 11:28:20-0400, Hugo Villeneuve wrote: > On Thu, 10 Mar 2022 21:58:49 +0100 > Alexandre Belloni wrote: > > > On 10/03/2022 11:09:18-0500, Hugo Villeneuve wrote: > > > On Wed, 9 Mar 2022 17:22:42 +0100 > > > Alexandre Belloni wrote: > > > > > > > The PCF2127 doesn't support UIE because setting an alarm to fire every > > > > second confuses the chip and the fastest we can go is an alarm every 2 > > > > seconds. > > > > > > Hi Alexandre, > > > can you describe what "confuses the chip" means? > > > > > > In my experimental PCF2131 driver, I activated UIE and it seems to be working fine at 1s intervals, but since it is similar to PCF2127, maybe there is still a problem and I just didn't see it. > > > > > > > Did you remove uie_unsupported? Else, you may have been using uie > > emulation. In my tests last year, the pcf2127 was failing to reassert > > the interrupt if an alarm was set every second. The same happens on > > other NXP based RTCs (i.e. including microcrystal ones). > > > > I'm going to test again soon (and also reply to your series). > > Hi, > I have now access to a board with a PCF2129T. > I actually did the test again this afternoon with a pcf2127... > I have been able to test with it by sending ioctl RTC_UIE_ON and > confirm that it exhibits the problem you reported. Basically, the > first alarm triggers the IRQ after 1s, as expected, but the next > configured alarm 1s into the future never triggers the IRQ again. But > the time/date registers seem to be updating (incrementin) correctly > after that. > ...and so we agree on what we observe. My guess is that the alarm comparator has a latch that triggers only every second update and so you need 2 seconds between each alarms. [...] > I even did some tests where, in pcf2127_rtc_set_alarm(), I disabled > all the alarm registers (set to 0x80), except for the SECONDS alarm > register. In this case, I observed that the IRQ is triggered after > 61s. This seems to indicate that the alarm detection circuitry is > still somewhat operating (AF flag / INT pin), but there is probably a > bug in the IC when the configured alarm is close to current time after > AF is set once... > > I also have done other tests by disabling then re-enabling AIE, > stopping and restarting the oscillator (STOP bit), etc, but to no > avail. > > However, in pcf2127_rtc_set_alarm(), if I set the alarm 2s past the > current time, instead of 1s, then the IRQ is always triggered after > 2s. > > I have opened a support case with NXP to investigate this strange > behavior. Let me know if you ever get a reply. > > Hugo. > > > > > > Signed-off-by: Alexandre Belloni > > > > --- > > > > drivers/rtc/rtc-pcf2127.c | 1 + > > > > 1 file changed, 1 insertion(+) > > > > > > > > diff --git a/drivers/rtc/rtc-pcf2127.c b/drivers/rtc/rtc-pcf2127.c > > > > index f8469b134411..63b275b014bd 100644 > > > > --- a/drivers/rtc/rtc-pcf2127.c > > > > +++ b/drivers/rtc/rtc-pcf2127.c > > > > @@ -656,6 +656,7 @@ static int pcf2127_probe(struct device *dev, struct regmap *regmap, > > > > pcf2127->rtc->range_min = RTC_TIMESTAMP_BEGIN_2000; > > > > pcf2127->rtc->range_max = RTC_TIMESTAMP_END_2099; > > > > pcf2127->rtc->set_start_time = true; /* Sets actual start to 1970 */ > > > > + set_bit(RTC_FEATURE_ALARM_RES_2S, pcf2127->rtc->features); > > > > clear_bit(RTC_FEATURE_UPDATE_INTERRUPT, pcf2127->rtc->features); > > > > clear_bit(RTC_FEATURE_ALARM, pcf2127->rtc->features); > > > > > > > > -- > > > > 2.35.1 > > > > > > > > > > > > > -- > > > Hugo Villeneuve > > > > -- > > Alexandre Belloni, co-owner and COO, Bootlin > > Embedded Linux and Kernel engineering > > https://bootlin.com > > > > > -- > Hugo Villeneuve -- Alexandre Belloni, co-owner and COO, Bootlin Embedded Linux and Kernel engineering https://bootlin.com