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[media] staging: media: lirc: Replace timeval with ktime_t in lirc_parallel.c 

'struct timeval tv' and 'struct timeval now' is used to calculate the
elapsed time. 'LIRC_SFH506_DELAY' is a delay t_phl in usecs.

32-bit systems using 'struct timeval' will break in the year 2038,
so we have to replace that code with more appropriate types.
This patch changes the lirc_parallel.c file of  media: lirc driver
to use ktime_t.

ktime_get() is  better than using do_gettimeofday(),
because it uses the monotonic clock. ktime_sub is used
to subtract two ktime variables. ktime_to_us() is used to
convert ktime to microsecond.

New ktime_t variable timeout, is added in lirc_off(),to improve
clarity. Introduced a new ktime_t variable in lirc_lirc_irq_handler()
function, to avoid the use of signal variable for storing
seconds in the first part of this function as later it uses
a time unit that is defined by the global "timer" variable.
This makes it more clear.

ktime_set() is used to set a value in seconds to a value in
nanosecond so that ktime_compare() can be used appropriately.
ktime_compare() is used to compare two ktime values.
ktime_add_ns() is used to increment a ktime value by 1 sec.

One comment is also shifted a line up, as it was creating a 80
character warning.

Build tested it. Also tested it with sparse.

Signed-off-by: Tapasweni Pathak <tapaswenipathak@gmail.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
This commit is contained in:
Arnd Bergmann 2015-11-25 13:13:26 -02:00 committed by Mauro Carvalho Chehab
parent f07c73fea2
commit 0dbf41a3c8
1 changed files with 15 additions and 20 deletions
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35
drivers/staging/media/lirc/lirc_parallel.c
View File

@ -33,7 +33,7 @@
#include <linux/fs.h>
#include <linux/kernel.h>
#include <linux/ioport.h>
#include <linux/time.h>
#include <linux/ktime.h>
#include <linux/mm.h>
#include <linux/delay.h>
@ -144,25 +144,22 @@ static void lirc_off(void)
static unsigned int init_lirc_timer(void)
{
struct timeval tv, now;
ktime_t kt, now, timeout;
unsigned int level, newlevel, timeelapsed, newtimer;
int count = 0;
do_gettimeofday(&tv);
tv.tv_sec++; /* wait max. 1 sec. */
kt = ktime_get();
/* wait max. 1 sec. */
timeout = ktime_add_ns(kt, NSEC_PER_SEC);
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);
now = ktime_get();
} while (count < 1000 && (ktime_before(now, timeout)));
timeelapsed = ktime_us_delta(now, kt);
if (count >= 1000 && timeelapsed > 0) {
if (default_timer == 0) {
/* autodetect timer */
@ -220,8 +217,8 @@ static void rbuf_write(int signal)
static void lirc_lirc_irq_handler(void *blah)
{
struct timeval tv;
static struct timeval lasttv;
ktime_t kt, delkt;
static ktime_t lastkt;
static int init;
long signal;
int data;
@ -244,16 +241,14 @@ static void lirc_lirc_irq_handler(void *blah)
#ifdef LIRC_TIMER
if (init) {
do_gettimeofday(&tv);
kt = ktime_get();
signal = tv.tv_sec - lasttv.tv_sec;
if (signal > 15)
delkt = ktime_sub(kt, lastkt);
if (ktime_compare(delkt, ktime_set(15, 0)) > 0)
/* really long time */
data = PULSE_MASK;
else
data = (int) (signal*1000000 +
tv.tv_usec - lasttv.tv_usec +
LIRC_SFH506_DELAY);
data = (int)(ktime_to_us(delkt) + LIRC_SFH506_DELAY);
rbuf_write(data); /* space */
} else {
@ -301,7 +296,7 @@ static void lirc_lirc_irq_handler(void *blah)
data = 1;
rbuf_write(PULSE_BIT|data); /* pulse */
}
do_gettimeofday(&lasttv);
lastkt = ktime_get();
#else
/* add your code here */
#endif