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Date:   Wed, 10 Nov 2021 15:27:41 +0100
From:   Alexandre Belloni <alexandre.belloni@bootlin.com>
To:     Camel Guo <camelg@axis.com>
Cc:     Camel Guo <Camel.Guo@axis.com>,
        Alessandro Zummo <a.zummo@towertech.it>,
        kernel <kernel@axis.com>,
        "linux-rtc@vger.kernel.org" <linux-rtc@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] rtc: rs5c372: Add RTC_VL_READ, RTC_VL_CLR ioctls
Message-ID: <YYvW3T3wM/Qn5jSw@piout.net>
References: <20211110115455.18699-1-camel.guo@axis.com>
 <YYvPCehWWVE5mKTy@piout.net>
 <2303e635-dbd0-1730-cc6f-84021eb37223@axis.com>
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On 10/11/2021 15:03:49+0100, Camel Guo wrote:
> > On 10/11/2021 12:54:54+0100, Camel Guo wrote:
> > > From: Camel Guo <camelg@axis.com>
> > > +???? switch (cmd) {
> > > +???? case RTC_VL_READ:
> > > +???????????? flags = 0;
> > > +
> > > +???????????? switch (rs5c->type) {
> > > +???????????? case rtc_r2025sd:
> > > +???????????? case rtc_r2221tl:
> > > +???????????????????? if ((rs5c->type == rtc_r2025sd && !(ctrl2 & R2x2x_CTRL2_XSTP)) ||
> > > +???????????????????????????? (rs5c->type == rtc_r2221tl &&? (ctrl2 & R2x2x_CTRL2_XSTP))) {
> > > +???????????????????????????? flags |= RTC_VL_DATA_INVALID;
> > > +???????????????????? }
> > > +???????????????????? if (ctrl2 & R2x2x_CTRL2_VDET)
> > > +???????????????????????????? flags |= RTC_VL_ACCURACY_LOW;
> > 
> > Shouldn't that be RTC_VL_BACKUP_LOW?
> 
> Some drivers (e.g: rv3029_ioctl and rv8803_ioctl) use RTC_VL_ACCURACY_LOW,
> but some other drivers (e.g: abx80x_ioctl, pcf2127_rtc_ioctl and
> pcf8523_rtc_ioctl) use RTC_VL_BACKUP_LOW instead. Is there any guideline or
> document telling the differences between them?
> 

RTC_VL_BACKUP_LOW: The backup voltage is low
RTC_VL_ACCURACY_LOW: the primary or backup voltage is low, temperature
compensation (or similar) has stopped

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