[media] dvb-frontend: Use boottime

Wall time obtained from ktime_get_real is susceptible to sudden jumps due to
user setting the time or due to NTP.  Boot time is constantly increasing time
better suited for comparing two timestamps.

[mchehab@osg.samsung.com: fix trivial merge conflicts]
Signed-off-by: Abhilash Jindal <klock.android@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>

drivers/media/dvb-core/dvb_frontend.c

@@ -899,10 +899,10 @@ void dvb_frontend_sleep_until(ktime_t *waketime, u32 add_usec)
 	s32 delta;
 
 	*waketime = ktime_add_us(*waketime, add_usec);
-	delta = ktime_us_delta(ktime_get_real(), *waketime);
+	delta = ktime_us_delta(ktime_get_boottime(), *waketime);
 	if (delta > 2500) {
 		msleep((delta - 1500) / 1000);
-		delta = ktime_us_delta(ktime_get_real(), *waketime);
+		delta = ktime_us_delta(ktime_get_boottime(), *waketime);
 	}
 	if (delta > 0)
 		udelay(delta);
@@ -2451,7 +2451,7 @@ static int dvb_frontend_ioctl_legacy(struct file *file,
 			u8 last = 1;
 			if (dvb_frontend_debug)
 				printk("%s switch command: 0x%04lx\n", __func__, swcmd);
-			nexttime = ktime_get_real();
+			nexttime = ktime_get_boottime();
 			if (dvb_frontend_debug)
 				tv[0] = nexttime;
 			/* before sending a command, initialize by sending
@@ -2462,7 +2462,7 @@ static int dvb_frontend_ioctl_legacy(struct file *file,
 
 			for (i = 0; i < 9; i++) {
 				if (dvb_frontend_debug)
-					tv[i+1] = ktime_get_real();
+					tv[i+1] = ktime_get_boottime();
 				if ((swcmd & 0x01) != last) {
 					/* set voltage to (last ? 13V : 18V) */
 					fe->ops.set_voltage(fe, (last) ? SEC_VOLTAGE_13 : SEC_VOLTAGE_18);

drivers/media/dvb-frontends/stv0299.c

@@ -422,7 +422,7 @@ static int stv0299_send_legacy_dish_cmd (struct dvb_frontend* fe, unsigned long
 	if (debug_legacy_dish_switch)
 		printk ("%s switch command: 0x%04lx\n",__func__, cmd);
 
-	nexttime = ktime_get_real();
+	nexttime = ktime_get_boottime();
 	if (debug_legacy_dish_switch)
 		tv[0] = nexttime;
 	stv0299_writeregI (state, 0x0c, reg0x0c | 0x50); /* set LNB to 18V */
@@ -431,7 +431,7 @@ static int stv0299_send_legacy_dish_cmd (struct dvb_frontend* fe, unsigned long
 
 	for (i=0; i<9; i++) {
 		if (debug_legacy_dish_switch)
-			tv[i+1] = ktime_get_real();
+			tv[i+1] = ktime_get_boottime();
 		if((cmd & 0x01) != last) {
 			/* set voltage to (last ? 13V : 18V) */
 			stv0299_writeregI (state, 0x0c, reg0x0c | (last ? lv_mask : 0x50));