Hello Alessandro Zummo,

The patch 0c86edc0d497: "[PATCH] RTC subsystem: class" from Mar 27,
2006, leads to the following static checker warning:

	drivers/rtc/rtc-r9701.c:109 r9701_set_datetime()
	error: undefined (user controlled) shift '1 << dt->tm_wday'

drivers/rtc/rtc-r9701.c
    95  static int r9701_set_datetime(struct device *dev, struct rtc_time *dt)
    96  {
    97          int ret, year;
    98  
    99          year = dt->tm_year + 1900;
   100          if (year >= 2100 || year < 2000)
   101                  return -EINVAL;
   102  
   103          ret = write_reg(dev, RHRCNT, bin2bcd(dt->tm_hour));
   104          ret = ret ? ret : write_reg(dev, RMINCNT, bin2bcd(dt->tm_min));
   105          ret = ret ? ret : write_reg(dev, RSECCNT, bin2bcd(dt->tm_sec));
   106          ret = ret ? ret : write_reg(dev, RDAYCNT, bin2bcd(dt->tm_mday));
   107          ret = ret ? ret : write_reg(dev, RMONCNT, bin2bcd(dt->tm_mon + 1));
   108          ret = ret ? ret : write_reg(dev, RYRCNT, bin2bcd(dt->tm_year - 100));
   109          ret = ret ? ret : write_reg(dev, RWKCNT, 1 << dt->tm_wday);

I would have expected that rtc_valid_tm() would check that dt->tm_wday
as valid but it doesn't.  As far as I can see dt->tm_wday can be set to
any int value in the rtc_dev_ioctl(). 

   110  
   111          return ret;
   112  }

regards,
dan carpenter