linux-kernel - Re: [PATCH 1/1] rtc: bbnsm: Enable RTC by default to fix time read failure

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Message-ID: <Z1Hg4OMwf+MfyhMO@lizhi-Precision-Tower-5810>
Date: Thu, 5 Dec 2024 12:20:32 -0500
From: Frank Li <Frank.li@....com>
To: Alexandre Belloni <alexandre.belloni@...tlin.com>
Cc: Jacky Bai <ping.bai@....com>, Peng Fan <peng.fan@....com>,
	"open list:REAL TIME CLOCK (RTC) SUBSYSTEM" <linux-rtc@...r.kernel.org>,
	open list <linux-kernel@...r.kernel.org>, imx@...ts.linux.dev
Subject: Re: [PATCH 1/1] rtc: bbnsm: Enable RTC by default to fix time read
 failure

On Mon, Nov 18, 2024 at 02:25:13PM -0500, Frank Li wrote:
> On Sun, Nov 17, 2024 at 11:08:43PM +0100, Alexandre Belloni wrote:
> > On 16/11/2024 20:36:54+0100, Alexandre Belloni wrote:
> > > On 15/11/2024 14:48:58-0500, Frank Li wrote:
> > > > From: Jacky Bai <ping.bai@....com>
> > > >
> > > > Enable the RTC by default even when no valid time is set to ensure the
> > > > RTC's time read and alarm functions work properly. Without this, running
> > > > hwclock results in the following error:
> > > >
> > > > hwclock: ioctl(RTC_RD_TIME) to /dev/rtc0 to read the time failed: Invalid argument
> > > >
> > >
> > >
> > > What is providing your hwclock and which version does it have?
> >
> >
> > This is a bug in util-linux that needs to be fixed.

Alexandre:

	I can't understand what your means. Why it is util-linux issue?
This driver return failure at read because check hardware bit RTC_EN.

	I suppose RTC should be always enable after probe?

Frank

>
> What's suposed/expected beheavor? I think rtc should be enable by default.
>
> Frank
>
> > >
> > >
> > > > Fixes: eb7b85853c38 ("rtc: bbnsm: Add the bbnsm rtc support")
> > > > Signed-off-by: Jacky Bai <ping.bai@....com>
> > > > Signed-off-by: Dong Aisheng <aisheng.dong@....com>
> > > > Signed-off-by: Frank Li <Frank.Li@....com>
> > > > ---
> > > >  drivers/rtc/rtc-nxp-bbnsm.c | 3 +++
> > > >  1 file changed, 3 insertions(+)
> > > >
> > > > diff --git a/drivers/rtc/rtc-nxp-bbnsm.c b/drivers/rtc/rtc-nxp-bbnsm.c
> > > > index fa3b0328c7a25..6610db2f75125 100644
> > > > --- a/drivers/rtc/rtc-nxp-bbnsm.c
> > > > +++ b/drivers/rtc/rtc-nxp-bbnsm.c
> > > > @@ -189,6 +189,9 @@ static int bbnsm_rtc_probe(struct platform_device *pdev)
> > > >  	/* clear all the pending events */
> > > >  	regmap_write(bbnsm->regmap, BBNSM_EVENTS, 0x7A);
> > > >
> > > > +	/* Enable the Real-Time counter */
> > > > +	regmap_update_bits(bbnsm->regmap, BBNSM_CTRL, RTC_EN_MSK, RTC_EN);
> > > > +
> > > >  	device_init_wakeup(&pdev->dev, true);
> > > >  	dev_pm_set_wake_irq(&pdev->dev, bbnsm->irq);
> > > >
> > > > --
> > > > 2.34.1
> > > >
> > >
> > > --
> > > Alexandre Belloni, co-owner and COO, Bootlin
> > > Embedded Linux and Kernel engineering
> > > https://bootlin.com
> >
> > --
> > Alexandre Belloni, co-owner and COO, Bootlin
> > Embedded Linux and Kernel engineering
> > https://bootlin.com