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commit 679c397401d8665ed5cba2811715d16dc98351d3 Author: Javier Alonso <[email protected]> AuthorDate: Fri Jul 24 12:16:30 2026 +0200 WDOG: Output status on read Currently, the `read` function of the watchdog device is dummy and does nothing. Although this is fine, it's not useful at all from a userspace perspective, where you may want to check the current WDOG status. A wrapper around the `ioctl` `WDIOC_GETSTATUS` has been added as the `read` function for the WDOG. Signed-off-by: Javier Alonso <[email protected]> --- drivers/timers/watchdog.c | 53 ++++++++++++++++++++++++++++++++++++++++++++--- 1 file changed, 50 insertions(+), 3 deletions(-) diff --git a/drivers/timers/watchdog.c b/drivers/timers/watchdog.c index 923672a107d..106abc8eb11 100644 --- a/drivers/timers/watchdog.c +++ b/drivers/timers/watchdog.c @@ -34,6 +34,7 @@ #include <fcntl.h> #include <assert.h> #include <errno.h> +#include <stdio.h> #include <nuttx/debug.h> #include <nuttx/fs/fs.h> @@ -552,16 +553,62 @@ errout: * Name: wdog_read * * Description: - * A dummy read method. This is provided only to satisfy the VFS layer. + * Return the current status of the watchdog timer. Mimics what an `ioctl` + * with `WDIOC_GETSTATUS` would do. This is useful for userspace to get the + * current status of the watchdog timer by just reading from the device. + * + * Returns: + * The number of bytes read on success, or a negated errno value on failure * ****************************************************************************/ static ssize_t wdog_read(FAR struct file *filep, FAR char *buffer, size_t buflen) { - /* Return zero -- usually meaning end-of-file */ + /* simulate a "get status" on the userspace */ - return 0; + ssize_t ret; + FAR struct watchdog_status_s status; + + /* the f_pos is not used along this driver. + * Use it as a marker to know if the status has been read already. + */ + + if (filep->f_pos) + { + filep->f_pos = 0; + return 0; + } + + ret = wdog_ioctl(filep, WDIOC_GETSTATUS, (uintptr_t)&status); + if (ret < 0) + { + return ret; + } + + /* Copy the watchdog status into the user buffer */ + + ret = snprintf( + buffer, + buflen, + "Status :\n" + " flags : 0x%08" PRIx32 "\n" + " timeout : %" PRId32 "\n" + " timeleft : %" PRId32 "\n", + status.flags, status.timeout, status.timeleft + ); + if (ret < 0) + { + return ret; + } + + if (ret >= buflen) + { + return -ENOSPC; + } + + filep->f_pos++; + return ret; } /****************************************************************************
