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watchdog: Improve watchdog_dev function documentation

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Adjust function comments to the kernel doc format. It
also adjusts some variable names and adds return values.

No functional change.

Changes from V1:
  Change "Returns" to "Return:" (Randy Dunlap)

Cc: Wim Van Sebroeck <wim@linux-watchdog.org>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: linux-watchdog@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Tested-by: Randy Dunlap <rdunlap@infradead.org>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/30378a03e9cd9b5f6e92ec9bf512edc38bad8627.1644589712.git.bristot@kernel.org
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
This commit is contained in:
Daniel Bristot de Oliveira 2022-02-11 15:30:14 +01:00 committed by Wim Van Sebroeck
parent 4ed1a6b6e6
commit ba6c89ab3b
1 changed files with 125 additions and 119 deletions
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244
drivers/watchdog/watchdog_dev.c
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@ -171,17 +171,17 @@ static int __watchdog_ping(struct watchdog_device *wdd)
} }
/* /*
* watchdog_ping: ping the watchdog. * watchdog_ping - ping the watchdog
* @wdd: the watchdog device to ping * @wdd: The watchdog device to ping
* *
* The caller must hold wd_data->lock. * If the watchdog has no own ping operation then it needs to be
* restarted via the start operation. This wrapper function does
* exactly that.
* We only ping when the watchdog device is running.
* The caller must hold wd_data->lock.
* *
* If the watchdog has no own ping operation then it needs to be * Return: 0 on success, error otherwise.
* restarted via the start operation. This wrapper function does
* exactly that.
* We only ping when the watchdog device is running.
*/ */
static int watchdog_ping(struct watchdog_device *wdd) static int watchdog_ping(struct watchdog_device *wdd)
{ {
struct watchdog_core_data *wd_data = wdd->wd_data; struct watchdog_core_data *wd_data = wdd->wd_data;
@ -231,16 +231,14 @@ static enum hrtimer_restart watchdog_timer_expired(struct hrtimer *timer)
} }
/* /*
* watchdog_start: wrapper to start the watchdog. * watchdog_start - wrapper to start the watchdog
* @wdd: the watchdog device to start * @wdd: The watchdog device to start
* *
* The caller must hold wd_data->lock. * Start the watchdog if it is not active and mark it active.
* The caller must hold wd_data->lock.
* *
* Start the watchdog if it is not active and mark it active. * Return: 0 on success or a negative errno code for failure.
* This function returns zero on success or a negative errno code for
* failure.
*/ */
static int watchdog_start(struct watchdog_device *wdd) static int watchdog_start(struct watchdog_device *wdd)
{ {
struct watchdog_core_data *wd_data = wdd->wd_data; struct watchdog_core_data *wd_data = wdd->wd_data;
@ -274,17 +272,15 @@ static int watchdog_start(struct watchdog_device *wdd)
} }
/* /*
* watchdog_stop: wrapper to stop the watchdog. * watchdog_stop - wrapper to stop the watchdog
* @wdd: the watchdog device to stop * @wdd: The watchdog device to stop
* *
* The caller must hold wd_data->lock. * Stop the watchdog if it is still active and unmark it active.
* If the 'nowayout' feature was set, the watchdog cannot be stopped.
* The caller must hold wd_data->lock.
* *
* Stop the watchdog if it is still active and unmark it active. * Return: 0 on success or a negative errno code for failure.
* This function returns zero on success or a negative errno code for
* failure.
* If the 'nowayout' feature was set, the watchdog cannot be stopped.
*/ */
static int watchdog_stop(struct watchdog_device *wdd) static int watchdog_stop(struct watchdog_device *wdd)
{ {
int err = 0; int err = 0;
@ -315,14 +311,14 @@ static int watchdog_stop(struct watchdog_device *wdd)
} }
/* /*
* watchdog_get_status: wrapper to get the watchdog status * watchdog_get_status - wrapper to get the watchdog status
* @wdd: the watchdog device to get the status from * @wdd: The watchdog device to get the status from
* *
* The caller must hold wd_data->lock. * Get the watchdog's status flags.
* The caller must hold wd_data->lock.
* *
* Get the watchdog's status flags. * Return: watchdog's status flags.
*/ */
static unsigned int watchdog_get_status(struct watchdog_device *wdd) static unsigned int watchdog_get_status(struct watchdog_device *wdd)
{ {
struct watchdog_core_data *wd_data = wdd->wd_data; struct watchdog_core_data *wd_data = wdd->wd_data;
@ -352,13 +348,14 @@ static unsigned int watchdog_get_status(struct watchdog_device *wdd)
} }
/* /*
* watchdog_set_timeout: set the watchdog timer timeout * watchdog_set_timeout - set the watchdog timer timeout
* @wdd: the watchdog device to set the timeout for * @wdd: The watchdog device to set the timeout for
* @timeout: timeout to set in seconds * @timeout: Timeout to set in seconds
* *
* The caller must hold wd_data->lock. * The caller must hold wd_data->lock.
*
* Return: 0 if successful, error otherwise.
*/ */
static int watchdog_set_timeout(struct watchdog_device *wdd, static int watchdog_set_timeout(struct watchdog_device *wdd,
unsigned int timeout) unsigned int timeout)
{ {
@ -385,11 +382,12 @@ static int watchdog_set_timeout(struct watchdog_device *wdd,
} }
/* /*
* watchdog_set_pretimeout: set the watchdog timer pretimeout * watchdog_set_pretimeout - set the watchdog timer pretimeout
* @wdd: the watchdog device to set the timeout for * @wdd: The watchdog device to set the timeout for
* @timeout: pretimeout to set in seconds * @timeout: pretimeout to set in seconds
*
* Return: 0 if successful, error otherwise.
*/ */
static int watchdog_set_pretimeout(struct watchdog_device *wdd, static int watchdog_set_pretimeout(struct watchdog_device *wdd,
unsigned int timeout) unsigned int timeout)
{ {
@ -410,15 +408,15 @@ static int watchdog_set_pretimeout(struct watchdog_device *wdd,
} }
/* /*
* watchdog_get_timeleft: wrapper to get the time left before a reboot * watchdog_get_timeleft - wrapper to get the time left before a reboot
* @wdd: the watchdog device to get the remaining time from * @wdd: The watchdog device to get the remaining time from
* @timeleft: the time that's left * @timeleft: The time that's left
* *
* The caller must hold wd_data->lock. * Get the time before a watchdog will reboot (if not pinged).
* The caller must hold wd_data->lock.
* *
* Get the time before a watchdog will reboot (if not pinged). * Return: 0 if successful, error otherwise.
*/ */
static int watchdog_get_timeleft(struct watchdog_device *wdd, static int watchdog_get_timeleft(struct watchdog_device *wdd,
unsigned int *timeleft) unsigned int *timeleft)
{ {
@ -635,14 +633,15 @@ __ATTRIBUTE_GROUPS(wdt);
#endif #endif
/* /*
* watchdog_ioctl_op: call the watchdog drivers ioctl op if defined * watchdog_ioctl_op - call the watchdog drivers ioctl op if defined
* @wdd: the watchdog device to do the ioctl on * @wdd: The watchdog device to do the ioctl on
* @cmd: watchdog command * @cmd: Watchdog command
* @arg: argument pointer * @arg: Argument pointer
* *
* The caller must hold wd_data->lock. * The caller must hold wd_data->lock.
*
* Return: 0 if successful, error otherwise.
*/ */
static int watchdog_ioctl_op(struct watchdog_device *wdd, unsigned int cmd, static int watchdog_ioctl_op(struct watchdog_device *wdd, unsigned int cmd,
unsigned long arg) unsigned long arg)
{ {
@ -653,17 +652,18 @@ static int watchdog_ioctl_op(struct watchdog_device *wdd, unsigned int cmd,
} }
/* /*
* watchdog_write: writes to the watchdog. * watchdog_write - writes to the watchdog
* @file: file from VFS * @file: File from VFS
* @data: user address of data * @data: User address of data
* @len: length of data * @len: Length of data
* @ppos: pointer to the file offset * @ppos: Pointer to the file offset
* *
* A write to a watchdog device is defined as a keepalive ping. * A write to a watchdog device is defined as a keepalive ping.
* Writing the magic 'V' sequence allows the next close to turn * Writing the magic 'V' sequence allows the next close to turn
* off the watchdog (if 'nowayout' is not set). * off the watchdog (if 'nowayout' is not set).
*
* Return: @len if successful, error otherwise.
*/ */
static ssize_t watchdog_write(struct file *file, const char __user *data, static ssize_t watchdog_write(struct file *file, const char __user *data,
size_t len, loff_t *ppos) size_t len, loff_t *ppos)
{ {
@ -706,13 +706,15 @@ static ssize_t watchdog_write(struct file *file, const char __user *data,
} }
/* /*
* watchdog_ioctl: handle the different ioctl's for the watchdog device. * watchdog_ioctl - handle the different ioctl's for the watchdog device
* @file: file handle to the device * @file: File handle to the device
* @cmd: watchdog command * @cmd: Watchdog command
* @arg: argument pointer * @arg: Argument pointer
* *
* The watchdog API defines a common set of functions for all watchdogs * The watchdog API defines a common set of functions for all watchdogs
* according to their available features. * according to their available features.
*
* Return: 0 if successful, error otherwise.
*/ */
static long watchdog_ioctl(struct file *file, unsigned int cmd, static long watchdog_ioctl(struct file *file, unsigned int cmd,
@ -819,15 +821,16 @@ out_ioctl:
} }
/* /*
* watchdog_open: open the /dev/watchdog* devices. * watchdog_open - open the /dev/watchdog* devices
* @inode: inode of device * @inode: Inode of device
* @file: file handle to device * @file: File handle to device
* *
* When the /dev/watchdog* device gets opened, we start the watchdog. * When the /dev/watchdog* device gets opened, we start the watchdog.
* Watch out: the /dev/watchdog device is single open, so we make sure * Watch out: the /dev/watchdog device is single open, so we make sure
* it can only be opened once. * it can only be opened once.
*
* Return: 0 if successful, error otherwise.
*/ */
static int watchdog_open(struct inode *inode, struct file *file) static int watchdog_open(struct inode *inode, struct file *file)
{ {
struct watchdog_core_data *wd_data; struct watchdog_core_data *wd_data;
@ -896,15 +899,16 @@ static void watchdog_core_data_release(struct device *dev)
} }
/* /*
* watchdog_release: release the watchdog device. * watchdog_release - release the watchdog device
* @inode: inode of device * @inode: Inode of device
* @file: file handle to device * @file: File handle to device
* *
* This is the code for when /dev/watchdog gets closed. We will only * This is the code for when /dev/watchdog gets closed. We will only
* stop the watchdog when we have received the magic char (and nowayout * stop the watchdog when we have received the magic char (and nowayout
* was not set), else the watchdog will keep running. * was not set), else the watchdog will keep running.
*
* Always returns 0.
*/ */
static int watchdog_release(struct inode *inode, struct file *file) static int watchdog_release(struct inode *inode, struct file *file)
{ {
struct watchdog_core_data *wd_data = file->private_data; struct watchdog_core_data *wd_data = file->private_data;
@ -977,14 +981,15 @@ static struct class watchdog_class = {
}; };
/* /*
* watchdog_cdev_register: register watchdog character device * watchdog_cdev_register - register watchdog character device
* @wdd: watchdog device * @wdd: Watchdog device
* *
* Register a watchdog character device including handling the legacy * Register a watchdog character device including handling the legacy
* /dev/watchdog node. /dev/watchdog is actually a miscdevice and * /dev/watchdog node. /dev/watchdog is actually a miscdevice and
* thus we set it up like that. * thus we set it up like that.
*
* Return: 0 if successful, error otherwise.
*/ */
static int watchdog_cdev_register(struct watchdog_device *wdd) static int watchdog_cdev_register(struct watchdog_device *wdd)
{ {
struct watchdog_core_data *wd_data; struct watchdog_core_data *wd_data;
@ -1074,13 +1079,12 @@ static int watchdog_cdev_register(struct watchdog_device *wdd)
} }
/* /*
* watchdog_cdev_unregister: unregister watchdog character device * watchdog_cdev_unregister - unregister watchdog character device
* @watchdog: watchdog device * @wdd: Watchdog device
* *
* Unregister watchdog character device and if needed the legacy * Unregister watchdog character device and if needed the legacy
* /dev/watchdog device. * /dev/watchdog device.
*/ */
static void watchdog_cdev_unregister(struct watchdog_device *wdd) static void watchdog_cdev_unregister(struct watchdog_device *wdd)
{ {
struct watchdog_core_data *wd_data = wdd->wd_data; struct watchdog_core_data *wd_data = wdd->wd_data;
@ -1109,15 +1113,16 @@ static void watchdog_cdev_unregister(struct watchdog_device *wdd)
put_device(&wd_data->dev); put_device(&wd_data->dev);
} }
/* /**
* watchdog_dev_register: register a watchdog device * watchdog_dev_register - register a watchdog device
* @wdd: watchdog device * @wdd: Watchdog device
* *
* Register a watchdog device including handling the legacy * Register a watchdog device including handling the legacy
* /dev/watchdog node. /dev/watchdog is actually a miscdevice and * /dev/watchdog node. /dev/watchdog is actually a miscdevice and
* thus we set it up like that. * thus we set it up like that.
*
* Return: 0 if successful, error otherwise.
*/ */
int watchdog_dev_register(struct watchdog_device *wdd) int watchdog_dev_register(struct watchdog_device *wdd)
{ {
int ret; int ret;
@ -1133,30 +1138,31 @@ int watchdog_dev_register(struct watchdog_device *wdd)
return ret; return ret;
} }
/* /**
* watchdog_dev_unregister: unregister a watchdog device * watchdog_dev_unregister - unregister a watchdog device
* @watchdog: watchdog device * @wdd: watchdog device
* *
* Unregister watchdog device and if needed the legacy * Unregister watchdog device and if needed the legacy
* /dev/watchdog device. * /dev/watchdog device.
*/ */
void watchdog_dev_unregister(struct watchdog_device *wdd) void watchdog_dev_unregister(struct watchdog_device *wdd)
{ {
watchdog_unregister_pretimeout(wdd); watchdog_unregister_pretimeout(wdd);
watchdog_cdev_unregister(wdd); watchdog_cdev_unregister(wdd);
} }
/* /**
* watchdog_set_last_hw_keepalive: set last HW keepalive time for watchdog * watchdog_set_last_hw_keepalive - set last HW keepalive time for watchdog
* @wdd: watchdog device * @wdd: Watchdog device
* @last_ping_ms: time since last HW heartbeat * @last_ping_ms: Time since last HW heartbeat
* *
* Adjusts the last known HW keepalive time for a watchdog timer. * Adjusts the last known HW keepalive time for a watchdog timer.
* This is needed if the watchdog is already running when the probe * This is needed if the watchdog is already running when the probe
* function is called, and it can't be pinged immediately. This * function is called, and it can't be pinged immediately. This
* function must be called immediately after watchdog registration, * function must be called immediately after watchdog registration,
* and min_hw_heartbeat_ms must be set for this to be useful. * and min_hw_heartbeat_ms must be set for this to be useful.
*
* Return: 0 if successful, error otherwise.
*/ */
int watchdog_set_last_hw_keepalive(struct watchdog_device *wdd, int watchdog_set_last_hw_keepalive(struct watchdog_device *wdd,
unsigned int last_ping_ms) unsigned int last_ping_ms)
@ -1180,12 +1186,13 @@ int watchdog_set_last_hw_keepalive(struct watchdog_device *wdd,
} }
EXPORT_SYMBOL_GPL(watchdog_set_last_hw_keepalive); EXPORT_SYMBOL_GPL(watchdog_set_last_hw_keepalive);
/* /**
* watchdog_dev_init: init dev part of watchdog core * watchdog_dev_init - init dev part of watchdog core
* *
* Allocate a range of chardev nodes to use for watchdog devices * Allocate a range of chardev nodes to use for watchdog devices.
*
* Return: 0 if successful, error otherwise.
*/ */
int __init watchdog_dev_init(void) int __init watchdog_dev_init(void)
{ {
int err; int err;
@ -1218,12 +1225,11 @@ err_register:
return err; return err;
} }
/* /**
* watchdog_dev_exit: exit dev part of watchdog core * watchdog_dev_exit - exit dev part of watchdog core
* *
* Release the range of chardev nodes used for watchdog devices * Release the range of chardev nodes used for watchdog devices.
*/ */
void __exit watchdog_dev_exit(void) void __exit watchdog_dev_exit(void)
{ {
unregister_chrdev_region(watchdog_devt, MAX_DOGS); unregister_chrdev_region(watchdog_devt, MAX_DOGS);