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Commit 453d0744 authored by Moritz Fischer's avatar Moritz Fischer Committed by Alexandre Belloni
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rtc: ds1374: wdt: Fix issue with timeout scaling from secs to wdt ticks 



The issue is that the internal counter that triggers the watchdog reset
is actually running at 4096 Hz instead of 1Hz, therefore the value
given by userland (in sec) needs to be multiplied by 4096 to get the
correct behavior.

Fixes: 920f91e5 ("drivers/rtc/rtc-ds1374.c: add watchdog support")
Signed-off-by: default avatarMoritz Fischer <mdf@kernel.org>
Signed-off-by: default avatarAlexandre Belloni <alexandre.belloni@free-electrons.com>
parent 5d05e815

drivers/rtc/rtc-ds1374.c

+6 −1
Original line number Diff line number Diff line
@@ -525,6 +525,10 @@ static long ds1374_wdt_ioctl(struct file *file, unsigned int cmd, 
		if (get_user(new_margin, (int __user *)arg))

			return -EFAULT;



		/* the hardware's tick rate is 4096 Hz, so

		 * the counter value needs to be scaled accordingly

		 */

		new_margin <<= 12;

		if (new_margin < 1 || new_margin > 16777216)

			return -EINVAL;
@@ -533,7 +537,8 @@ static long ds1374_wdt_ioctl(struct file *file, unsigned int cmd, 
		ds1374_wdt_ping();

		/* fallthrough */

	case WDIOC_GETTIMEOUT:

		return put_user(wdt_margin, (int __user *)arg);

		/* when returning ... inverse is true */

		return put_user((wdt_margin >> 12), (int __user *)arg);

	case WDIOC_SETOPTIONS:

		if (copy_from_user(&options, (int __user *)arg, sizeof(int)))

			return -EFAULT;