linux-kernel - Re: [PATCH 1/2] rtc: da9063: set range

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Date:   Tue, 2 Apr 2019 10:53:25 +0200
From:   Alexandre Belloni <alexandre.belloni@...tlin.com>
To:     Wolfram Sang <wsa@...-dreams.de>
Cc:     Geert Uytterhoeven <geert@...ux-m68k.org>,
        Steve Twiss <stwiss.opensource@...semi.com>,
        "linux-rtc@...r.kernel.org" <linux-rtc@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Wolfram Sang <wsa+renesas@...g-engineering.com>,
        Support Opensource <Support.Opensource@...semi.com>,
        Linux-Renesas <linux-renesas-soc@...r.kernel.org>
Subject: Re: [PATCH 1/2] rtc: da9063: set range

On 01/04/2019 21:34:25+0200, Wolfram Sang wrote:
> 
> > Well, seeing the code, I actually remembered that this test is still
> > there to ensure the core will properly block. If you remove that test,
> > the other ones should all timeout.
> 
> Thanks for your assistance! What I did just now was to make use of the
> 'uie_unsupported' flag. This is the outcome:
> 
> 
> [==========] Running 7 tests from 2 test cases.
> [ RUN      ] rtc.date_read
> rtctest.c:49:rtc.date_read:Current RTC date/time is 01/01/2000 00:13:23.
> [       OK ] rtc.date_read
> [ RUN      ] rtc.uie_read
> [       OK ] rtc.uie_read
> [ RUN      ] rtc.uie_select
> [       OK ] rtc.uie_select
> [ RUN      ] rtc.alarm_alm_set
> rtctest.c:137:rtc.alarm_alm_set:Alarm time now set to 00:13:32.
> rtctest.c:148:rtc.alarm_alm_set:Expected 0 (0) != rc (0)
> rtc.alarm_alm_set: Test terminated by assertion
> [     FAIL ] rtc.alarm_alm_set
> [ RUN      ] rtc.alarm_wkalm_set
> rtctest.c:195:rtc.alarm_wkalm_set:Alarm time now set to 01/01/2000
> 00:13:37.
> rtctest.c:202:rtc.alarm_wkalm_set:Expected 0 (0) != rc (0)
> rtc.alarm_wkalm_set: Test terminated by assertion
> [     FAIL ] rtc.alarm_wkalm_set
> [ RUN      ] rtc.alarm_alm_set_minute
> rtctest.c:239:rtc.alarm_alm_set_minute:Alarm time now set to 00:14:00.
> rtctest.c:258:rtc.alarm_alm_set_minute:data: 1a0
> [       OK ] rtc.alarm_alm_set_minute
> [ RUN      ] rtc.alarm_wkalm_set_minute
> rtctest.c:297:rtc.alarm_wkalm_set_minute:Alarm time now set to
> 01/01/2000 00:15:00.
> [       OK ] rtc.alarm_wkalm_set_minute
> [==========] 5 / 7 tests passed.
> [  FAILED  ]
> 
> I wonder why the_set_minute tests pass, but the other ones fail. I also
> wonder why I need the uie_unsupported flag? It's been a while since I
> dug into the RTC subsystem, I may be missing something. But I see the
> UIE code finally calling into set_alarm for some codepath. We have that
> for DA9063, but it is not executed for the UIE test of rtctest. However,
> it seems the driver doesn't support this in an optimal way, because
> there is a currently unused update interrupt which should be used for
> UIE, or? I also wonder why all this works fine for Steve.
> 

I had a look at the driver and I guess you have a 9063AD while Steve
uses another model.

That explains why you need the uie_unsupported flag. The 9063AD can only
do alarms on a minute boundary.

Since the move to hr_timer, the uie are done using the classic alarm or
they are emulated by the core. This improved the situation for many RTCs
that don't have a separate UIE but this made it worse for a few (and
this is an example). I have plan to work on this but didn't have the
time yet.

I suggest the following patch:

===

>From 37b2ab7d537e76e42bde64cf4b57701b0ed8e8cd Mon Sep 17 00:00:00 2001
From: Alexandre Belloni <alexandre.belloni@...tlin.com>
Date: Tue, 2 Apr 2019 10:06:46 +0200
Subject: [PATCH] rtc: da9063: set uie_unsupported when relevant

The DA9063AD doesn't support alarms on any seconds and its granularity is
the minute. Set uie_unsupported in that case.

Reported-by: Wolfram Sang <wsa@...-dreams.de>
Reported-by: Geert Uytterhoeven <geert@...ux-m68k.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@...tlin.com>
---
 drivers/rtc/rtc-da9063.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/rtc/rtc-da9063.c b/drivers/rtc/rtc-da9063.c
index 1b792bcea3c7..53e690b0f3a2 100644
--- a/drivers/rtc/rtc-da9063.c
+++ b/drivers/rtc/rtc-da9063.c
@@ -475,6 +475,9 @@ static int da9063_rtc_probe(struct platform_device *pdev)
 	da9063_data_to_tm(data, &rtc->alarm_time, rtc);
 	rtc->rtc_sync = false;
 
+	if (config->rtc_data_start != RTC_SEC)
+		rtc->rtc_dev->uie_unsupported = 1;
+
 	irq_alarm = platform_get_irq_byname(pdev, "ALARM");
 	ret = devm_request_threaded_irq(&pdev->dev, irq_alarm, NULL,
 					da9063_alarm_event,
-- 
2.20.1


-- 
Alexandre Belloni, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com