diff options
| author | George Spelvin <linux@horizon.com> | 2013-02-10 04:08:32 -0500 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2013-03-06 03:23:57 +0000 |
| commit | 7063a9950d1005f4e797bd047eae7fda181209fb (patch) | |
| tree | fcddfef74341a4b9c40c9f90995b1b5292efb499 /include | |
| parent | 72df9eccdc41633b6eab5ef2489ff8acb8391c6c (diff) | |
pps: Add pps_lookup_dev() function
commit 513b032c98b4b9414aa4e9b4a315cb1bf0380101 upstream.
The PPS serial line discipline wants to attach a PPS device to a tty
without changing the tty code to add a struct pps_device * pointer.
Since the number of PPS devices in a typical system is generally very low
(n=1 is by far the most common), it's practical to search the entire list
of allocated pps devices. (We capture the timestamp before the lookup,
so the timing isn't affected.)
It is a bit ugly that this function, which is part of the in-kernel
PPS API, has to be in pps.c as opposed to kapi,c, but that's not
something that affects users.
Signed-off-by: George Spelvin <linux@horizon.com>
Acked-by: Rodolfo Giometti <giometti@enneenne.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/pps_kernel.h | 17 |
1 files changed, 14 insertions, 3 deletions
diff --git a/include/linux/pps_kernel.h b/include/linux/pps_kernel.h index 94048547f29..ce2ab3dbdcf 100644 --- a/include/linux/pps_kernel.h +++ b/include/linux/pps_kernel.h @@ -43,7 +43,7 @@ struct pps_source_info { int event, void *data); /* PPS echo function */ struct module *owner; - struct device *dev; + struct device *dev; /* Parent device for device_create */ }; struct pps_event_time { @@ -69,6 +69,7 @@ struct pps_device { wait_queue_head_t queue; /* PPS event queue */ unsigned int id; /* PPS source unique ID */ + void const *lookup_cookie; /* pps_lookup_dev only */ struct cdev cdev; struct device *dev; struct fasync_struct *async_queue; /* fasync method */ @@ -82,16 +83,26 @@ struct pps_device { extern struct device_attribute pps_attrs[]; /* + * Internal functions. + * + * These are not actually part of the exported API, but this is a + * convenient header file to put them in. + */ + +extern int pps_register_cdev(struct pps_device *pps); +extern void pps_unregister_cdev(struct pps_device *pps); + +/* * Exported functions */ extern struct pps_device *pps_register_source( struct pps_source_info *info, int default_params); extern void pps_unregister_source(struct pps_device *pps); -extern int pps_register_cdev(struct pps_device *pps); -extern void pps_unregister_cdev(struct pps_device *pps); extern void pps_event(struct pps_device *pps, struct pps_event_time *ts, int event, void *data); +/* Look up a pps device by magic cookie */ +struct pps_device *pps_lookup_dev(void const *cookie); static inline void timespec_to_pps_ktime(struct pps_ktime *kt, struct timespec ts) |