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From: Dan Carpenter <dan.carpenter@oracle.com>
To: u.kleine-koenig@pengutronix.de
Cc: linux-rtc@vger.kernel.org
Subject: [bug report] rtc: ds1307: rx8130: honor Voltage Loss Flag when reading the time
Date: Wed, 13 Feb 2019 16:17:31 +0300	[thread overview]
Message-ID: <20190213131731.GA29774@kadam> (raw)

Hello Uwe Kleine-König,

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.

    315 		if (result) {
    316 			dev_err(dev, "%s error %d\n", "write", result);
    317 			return result;
    318 		}
    319 	}
    320 
    321 	return 0;
    322 }

regards,
dan carpenter

             reply	other threads:[~2019-02-13 13:17 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-02-13 13:17 Dan Carpenter [this message]
2019-02-13 17:51 ` [bug report] rtc: ds1307: rx8130: honor Voltage Loss Flag when reading the time Uwe Kleine-König
2019-02-13 19:43   ` Dan Carpenter

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