On Fri 2020-01-24 10:31:31, Greg Kroah-Hartman wrote: > From: Bruno Thomsen <bruno.thomsen@xxxxxxxxx> > > [ Upstream commit 7f43020e3bdb63d65661ed377682702f8b34d3ea ] > > The previous fix listed bulk read of registers as root cause of > accendential disabling of watchdog, since the watchdog counter > register (WD_VAL) was zeroed. > > Fixes: 3769a375ab83 rtc: pcf2127: bulk read only date and time registers. > > Tested with the same PCF2127 chip as Sean reveled root cause > of WD_VAL register value zeroing was caused by reading CTRL2 > register which is one of the watchdog feature control registers. > > So the solution is to not read the first two control registers > (CTRL1 and CTRL2) in pcf2127_rtc_read_time as they are not > needed anyway. Size of local buf variable is kept to allow > easy usage of register defines to improve readability of code. Should the array be zeroed before or something? This way, one array contains both undefined values and valid data... > Debug trace line was updated after CTRL1 and CTRL2 are no longer > read from the chip. Also replaced magic numbers in buf access > with register defines. That part is not an improvement. Previously the code was formatted so that you could parse what is being printed. Best regards, Pavel > @@ -91,14 +85,12 @@ static int pcf2127_rtc_read_time(struct device *dev, struct rtc_time *tm) > } > > dev_dbg(dev, > - "%s: raw data is cr1=%02x, cr2=%02x, cr3=%02x, " > - "sec=%02x, min=%02x, hr=%02x, " > + "%s: raw data is cr3=%02x, sec=%02x, min=%02x, hr=%02x, " > "mday=%02x, wday=%02x, mon=%02x, year=%02x\n", > - __func__, > - buf[0], buf[1], buf[2], > - buf[3], buf[4], buf[5], > - buf[6], buf[7], buf[8], buf[9]); > - > + __func__, buf[PCF2127_REG_CTRL3], buf[PCF2127_REG_SC], > + buf[PCF2127_REG_MN], buf[PCF2127_REG_HR], > + buf[PCF2127_REG_DM], buf[PCF2127_REG_DW], > + buf[PCF2127_REG_MO], buf[PCF2127_REG_YR]); > > tm->tm_sec = bcd2bin(buf[PCF2127_REG_SC] & 0x7F); > tm->tm_min = bcd2bin(buf[PCF2127_REG_MN] & 0x7F); > -- > 2.20.1 > > -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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