From: Dan Carpenter <dan.carpenter@oracle.com>
To: "Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>
Cc: linux-rtc@vger.kernel.org
Subject: Re: [bug report] rtc: ds1307: rx8130: honor Voltage Loss Flag when reading the time
Date: Wed, 13 Feb 2019 22:43:32 +0300 [thread overview]
Message-ID: <20190213193847.GI5458@kadam> (raw)
In-Reply-To: <20190213175125.bpwwi2slm6lvjg3x@pengutronix.de>
On Wed, Feb 13, 2019 at 06:51:25PM +0100, Uwe Kleine-König wrote:
> Hello Dan,
>
> On Wed, Feb 13, 2019 at 04:17:31PM +0300, Dan Carpenter wrote:
> > The patch 501f98266cad: "rtc: ds1307: rx8130: honor Voltage Loss Flag
> > when reading the time" from Jan 25, 2019, leads to the following
> > static checker warning:
> >
> > drivers/rtc/rtc-ds1307.c:314 ds1307_set_time()
> > warn: this cast is a no-op
> >
> > drivers/rtc/rtc-ds1307.c
> > 304 result = regmap_bulk_write(ds1307->regmap, chip->offset, regs,
> > 305 sizeof(regs));
> > 306 if (result) {
> > 307 dev_err(dev, "%s error %d\n", "write", result);
> > 308 return result;
> > 309 }
> > 310
> > 311 if (ds1307->type == rx_8130) {
> > 312 /* clear Voltage Loss Flag as data is available now */
> > 313 result = regmap_write(ds1307->regmap, RX8130_REG_FLAG,
> > --> 314 ~(u8)RX8130_REG_FLAG_VLF);
> > ^^^^^^^^^^^^^^^^^^^^^^^^
> > RX8130_REG_FLAG_VLF is 0x2. The cast to u8 doesn't change anything
> > because it gets type promoted to int. I don't know what was intended.
>
> This reasoning looks right, yes. I don't remember why I added it.
> Probably because I intended to create the value 0xfd and not 0xfffffffd
> (aka -3).
>
> Feel free to fix this in a patch blaming me.
If it's working as-is then I'm not going to be the one to break it... :P
regards,
dan carpenter
prev parent reply other threads:[~2019-02-13 19:43 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-13 13:17 [bug report] rtc: ds1307: rx8130: honor Voltage Loss Flag when reading the time Dan Carpenter
2019-02-13 17:51 ` Uwe Kleine-König
2019-02-13 19:43 ` Dan Carpenter [this message]
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