Wall time obtained from do_gettimeofday is susceptible to sudden jumps due to
user setting the time or due to NTP. Monotonic time is constantly increasing
time better suited for comparing two timestamps.
Signed-off-by: Abhilash Jindal <klock.andr...@gmail.com>
---
drivers/staging/media/lirc/lirc_parallel.c | 42 ++++++++++++----------------
1 file changed, 18 insertions(+), 24 deletions(-)
diff --git a/drivers/staging/media/lirc/lirc_parallel.c
b/drivers/staging/media/lirc/lirc_parallel.c
index c140834..de2ec2e 100644
--- a/drivers/staging/media/lirc/lirc_parallel.c
+++ b/drivers/staging/media/lirc/lirc_parallel.c
@@ -144,33 +144,29 @@ static void lirc_off(void)
static unsigned int init_lirc_timer(void)
{
- struct timeval tv, now;
- unsigned int level, newlevel, timeelapsed, newtimer;
+ ktime_t tm, now;
+ unsigned int elapsedus, level, newlevel, newtimer;
int count = 0;
- do_gettimeofday(&tv);
- tv.tv_sec++; /* wait max. 1 sec. */
+ tm = ktime_get();
level = lirc_get_timer();
do {
newlevel = lirc_get_timer();
if (level == 0 && newlevel != 0)
count++;
level = newlevel;
- do_gettimeofday(&now);
- } while (count < 1000 && (now.tv_sec < tv.tv_sec
- || (now.tv_sec == tv.tv_sec
- && now.tv_usec < tv.tv_usec)));
-
- timeelapsed = (now.tv_sec + 1 - tv.tv_sec)*1000000
- + (now.tv_usec - tv.tv_usec);
- if (count >= 1000 && timeelapsed > 0) {
+ now = ktime_get();
+ elapsedus = ktime_us_delta(now, tm);
+ } while (count < 1000 && elapsedus < 1000000);/* wait max. 1 sec. */
+
+ if (count >= 1000 && elapsedus > 0) {
if (default_timer == 0) {
/* autodetect timer */
- newtimer = (1000000*count)/timeelapsed;
+ newtimer = (1000000*count)/elapsedus;
pr_info("%u Hz timer detected\n", newtimer);
return newtimer;
}
- newtimer = (1000000*count)/timeelapsed;
+ newtimer = (1000000*count)/elapsedus;
if (abs(newtimer - default_timer) > default_timer/10) {
/* bad timer */
pr_notice("bad timer: %u Hz\n", newtimer);
@@ -220,10 +216,10 @@ static void rbuf_write(int signal)
static void lirc_lirc_irq_handler(void *blah)
{
- struct timeval tv;
- static struct timeval lasttv;
+ ktime_t tm;
+ static ktime_t lasttm;
static int init;
- long signal;
+ long signal, elapsedus;
int data;
unsigned int level, newlevel;
unsigned int timeout;
@@ -244,16 +240,14 @@ static void lirc_lirc_irq_handler(void *blah)
#ifdef LIRC_TIMER
if (init) {
- do_gettimeofday(&tv);
-
- signal = tv.tv_sec - lasttv.tv_sec;
+ tm = ktime_get();
+ elapsedus = ktime_us_delta(tm, lasttm);
+ signal = elapsedus/USEC_PER_SEC;
if (signal > 15)
/* really long time */
data = PULSE_MASK;
else
- data = (int) (signal*1000000 +
- tv.tv_usec - lasttv.tv_usec +
- LIRC_SFH506_DELAY);
+ data = (int) (elapsedus + LIRC_SFH506_DELAY);
rbuf_write(data); /* space */
} else {
@@ -301,7 +295,7 @@ static void lirc_lirc_irq_handler(void *blah)
data = 1;
rbuf_write(PULSE_BIT|data); /* pulse */
}
- do_gettimeofday(&lasttv);
+ lasttm = ktime_get();
#else
/* add your code here */
#endif
--
1.7.9.5
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