From: Moritz Fischer Date: Mon, 24 Apr 2017 22:05:11 +0000 (-0700) Subject: rtc: ds1374: wdt: Fix issue with timeout scaling from secs to wdt ticks X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=453d0744f6c6ca3f9749b8c57c2e85b5b9f52514;p=GitHub%2Fmoto-9609%2Fandroid_kernel_motorola_exynos9610.git 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: 920f91e50c5b ("drivers/rtc/rtc-ds1374.c: add watchdog support") Signed-off-by: Moritz Fischer Signed-off-by: Alexandre Belloni --- diff --git a/drivers/rtc/rtc-ds1374.c b/drivers/rtc/rtc-ds1374.c index 4cd115e93223..2a8b5b3e429b 100644 --- a/drivers/rtc/rtc-ds1374.c +++ b/drivers/rtc/rtc-ds1374.c @@ -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;