diff options
Diffstat (limited to 'include/linux/surface_aggregator/device.h')
| -rw-r--r-- | include/linux/surface_aggregator/device.h | 66 |
1 files changed, 66 insertions, 0 deletions
diff --git a/include/linux/surface_aggregator/device.h b/include/linux/surface_aggregator/device.h index 6df7c8d4e50e..c418f7f2732d 100644 --- a/include/linux/surface_aggregator/device.h +++ b/include/linux/surface_aggregator/device.h @@ -483,4 +483,70 @@ static inline void ssam_remove_clients(struct device *dev) {} sdev->uid.instance, ret); \ } + +/* -- Helpers for client-device notifiers. ---------------------------------- */ + +/** + * ssam_device_notifier_register() - Register an event notifier for the + * specified client device. + * @sdev: The device the notifier should be registered on. + * @n: The event notifier to register. + * + * Register an event notifier. Increment the usage counter of the associated + * SAM event if the notifier is not marked as an observer. If the event is not + * marked as an observer and is currently not enabled, it will be enabled + * during this call. If the notifier is marked as an observer, no attempt will + * be made at enabling any event and no reference count will be modified. + * + * Notifiers marked as observers do not need to be associated with one specific + * event, i.e. as long as no event matching is performed, only the event target + * category needs to be set. + * + * Return: Returns zero on success, %-ENOSPC if there have already been + * %INT_MAX notifiers for the event ID/type associated with the notifier block + * registered, %-ENOMEM if the corresponding event entry could not be + * allocated, %-ENODEV if the device is marked as hot-removed. If this is the + * first time that a notifier block is registered for the specific associated + * event, returns the status of the event-enable EC-command. + */ +static inline int ssam_device_notifier_register(struct ssam_device *sdev, + struct ssam_event_notifier *n) +{ + /* + * Note that this check does not provide any guarantees whatsoever as + * hot-removal could happen at any point and we can't protect against + * it. Nevertheless, if we can detect hot-removal, bail early to avoid + * communication timeouts. + */ + if (ssam_device_is_hot_removed(sdev)) + return -ENODEV; + + return ssam_notifier_register(sdev->ctrl, n); +} + +/** + * ssam_device_notifier_unregister() - Unregister an event notifier for the + * specified client device. + * @sdev: The device the notifier has been registered on. + * @n: The event notifier to unregister. + * + * Unregister an event notifier. Decrement the usage counter of the associated + * SAM event if the notifier is not marked as an observer. If the usage counter + * reaches zero, the event will be disabled. + * + * In case the device has been marked as hot-removed, the event will not be + * disabled on the EC, as in those cases any attempt at doing so may time out. + * + * Return: Returns zero on success, %-ENOENT if the given notifier block has + * not been registered on the controller. If the given notifier block was the + * last one associated with its specific event, returns the status of the + * event-disable EC-command. + */ +static inline int ssam_device_notifier_unregister(struct ssam_device *sdev, + struct ssam_event_notifier *n) +{ + return __ssam_notifier_unregister(sdev->ctrl, n, + !ssam_device_is_hot_removed(sdev)); +} + #endif /* _LINUX_SURFACE_AGGREGATOR_DEVICE_H */ |