pps: events reporting fix up

PPS events must be recorded according to PPS's mode settings.

If a process asks for (i.e.) capture-assert events only, when the PPS
client calls the pps_event() function to save the current PPS event, we
should verify the event type and then discard unwanted ones.

Also, without this patch userland processes waiting for a specific PPS
event (assert or clear but not both) may be awakened at wrong time.

Signed-off-by: Rodolfo Giometti <giometti@linux.it>
Tested-by: William S. Brasher <billb958@door.net>
Tested-by: Reg Clemens <clemens@dwf.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 15 insertions, 5 deletions

diff --git a/drivers/pps/kapi.c b/drivers/pps/kapi.c
index 35a0b192d768..2d414e23d390 100644
--- a/drivers/pps/kapi.c
+++ b/drivers/pps/kapi.c
@@ -271,6 +271,7 @@ void pps_event(int source, struct pps_ktime *ts, int event, void *data)
 {
         struct pps_device *pps;
         unsigned long flags;
+        int captured = 0;
 
         if ((event & (PPS_CAPTUREASSERT | PPS_CAPTURECLEAR)) == 0) {
                 printk(KERN_ERR "pps: unknown event (%x) for source %d\n",
@@ -293,7 +294,8 @@ void pps_event(int source, struct pps_ktime *ts, int event, void *data)
 
         /* Check the event */
         pps->current_mode = pps->params.mode;
-        if (event & PPS_CAPTUREASSERT) {
+        if ((event & PPS_CAPTUREASSERT) &
+                        (pps->params.mode & PPS_CAPTUREASSERT)) {
                 /* We have to add an offset? */
                 if (pps->params.mode & PPS_OFFSETASSERT)
                         pps_add_offset(ts, &pps->params.assert_off_tu);
@@ -303,8 +305,11 @@ void pps_event(int source, struct pps_ktime *ts, int event, void *data)
                 pps->assert_sequence++;
                 pr_debug("capture assert seq #%u for source %d\n",
                         pps->assert_sequence, source);
+
+                captured = ~0;
         }
-        if (event & PPS_CAPTURECLEAR) {
+        if ((event & PPS_CAPTURECLEAR) &
+                        (pps->params.mode & PPS_CAPTURECLEAR)) {
                 /* We have to add an offset? */
                 if (pps->params.mode & PPS_OFFSETCLEAR)
                         pps_add_offset(ts, &pps->params.clear_off_tu);
@@ -314,12 +319,17 @@ void pps_event(int source, struct pps_ktime *ts, int event, void *data)
                 pps->clear_sequence++;
                 pr_debug("capture clear seq #%u for source %d\n",
                         pps->clear_sequence, source);
+
+                captured = ~0;
         }
 
-        pps->go = ~0;
-        wake_up_interruptible(&pps->queue);
+        /* Wake up iif captured somthing */
+        if (captured) {
+                pps->go = ~0;
+                wake_up_interruptible(&pps->queue);
 
-        kill_fasync(&pps->async_queue, SIGIO, POLL_IN);
+                kill_fasync(&pps->async_queue, SIGIO, POLL_IN);
+        }
 
         spin_unlock_irqrestore(&pps->lock, flags);