diff --git a/components/libc/compilers/armlibc/time.c b/components/libc/compilers/armlibc/time.c
index 29c5c6cdd2ca818a9cb8ca3b0a1ea60f10a6a5d3..f099d51330da569b8b3f3bb1c53e57f222870d32 100644
--- a/components/libc/compilers/armlibc/time.c
+++ b/components/libc/compilers/armlibc/time.c
@@ -16,19 +16,16 @@ int gettimeofday(struct timeval *tp, void *ignore)
     rt_device_t device;
 
     device = rt_device_find("rtc");
-    if (device != RT_NULL)
-    {
-        rt_device_control(device, RT_DEVICE_CTRL_RTC_GET_TIME, &time);
-        if (tp != RT_NULL)
-        {
-            tp->tv_sec = time;
-            tp->tv_usec = 0;
-        }
+    RT_ASSERT(device != RT_NULL);
 
-        return time;
+    rt_device_control(device, RT_DEVICE_CTRL_RTC_GET_TIME, &time);
+    if (tp != RT_NULL)
+    {
+        tp->tv_sec = time;
+        tp->tv_usec = 0;
     }
 
-    return 0;
+    return time;
 }
 #endif
 
diff --git a/components/libc/compilers/dlib/time.c b/components/libc/compilers/dlib/time.c
index 87574df85152dfb562f3004319a7e026cdc2aa00..df35313b0ebb07ec3f5c475d99c658d9c01ef414 100644
--- a/components/libc/compilers/dlib/time.c
+++ b/components/libc/compilers/dlib/time.c
@@ -16,19 +16,16 @@ int gettimeofday(struct timeval *tp, void *ignore)
     rt_device_t device;
 
     device = rt_device_find("rtc");
-    if (device != RT_NULL)
-    {
-        rt_device_control(device, RT_DEVICE_CTRL_RTC_GET_TIME, &time);
-        if (tp != RT_NULL)
-        {
-            tp->tv_sec = time;
-            tp->tv_usec = 0;
-        }
+    RT_ASSERT(device != RT_NULL);
 
-        return time;
+    rt_device_control(device, RT_DEVICE_CTRL_RTC_GET_TIME, &time);
+    if (tp != RT_NULL)
+    {
+        tp->tv_sec = time;
+        tp->tv_usec = 0;
     }
 
-    return 0;
+    return time;
 }
 #endif
 
diff --git a/components/libc/compilers/minilibc/time.c b/components/libc/compilers/minilibc/time.c
index 508558bafc3cd702e837a615fbe047cdfd8cbe40..25e8f0e310d04a552278c43f462927cc46973f2b 100644
--- a/components/libc/compilers/minilibc/time.c
+++ b/components/libc/compilers/minilibc/time.c
@@ -11,20 +11,20 @@
 
 /* days per month -- nonleap! */
 const short __spm[13] =
-  { 0,
+{   0,
     (31),
-    (31+28),
-    (31+28+31),
-    (31+28+31+30),
-    (31+28+31+30+31),
-    (31+28+31+30+31+30),
-    (31+28+31+30+31+30+31),
-    (31+28+31+30+31+30+31+31),
-    (31+28+31+30+31+30+31+31+30),
-    (31+28+31+30+31+30+31+31+30+31),
-    (31+28+31+30+31+30+31+31+30+31+30),
-    (31+28+31+30+31+30+31+31+30+31+30+31),
-  };
+    (31 + 28),
+    (31 + 28 + 31),
+    (31 + 28 + 31 + 30),
+    (31 + 28 + 31 + 30 + 31),
+    (31 + 28 + 31 + 30 + 31 + 30),
+    (31 + 28 + 31 + 30 + 31 + 30 + 31),
+    (31 + 28 + 31 + 30 + 31 + 30 + 31 + 31),
+    (31 + 28 + 31 + 30 + 31 + 30 + 31 + 31 + 30),
+    (31 + 28 + 31 + 30 + 31 + 30 + 31 + 31 + 30 + 31),
+    (31 + 28 + 31 + 30 + 31 + 30 + 31 + 31 + 30 + 31 + 30),
+    (31 + 28 + 31 + 30 + 31 + 30 + 31 + 31 + 30 + 31 + 30 + 31),
+};
 static long int timezone;
 static const char days[] = "Sun Mon Tue Wed Thu Fri Sat ";
 static const char months[] = "Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec ";
@@ -34,196 +34,193 @@ static const char months[] = "Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec ";
 
 int __isleap(int year)
 {
-	/* every fourth year is a leap year except for century years that are
-	 * not divisible by 400. */
-	/*  return (year % 4 == 0 && (year % 100 != 0 || year % 400 == 0)); */
-	return (!(year % 4) && ((year % 100) || !(year % 400)));
+    /* every fourth year is a leap year except for century years that are
+     * not divisible by 400. */
+    /*  return (year % 4 == 0 && (year % 100 != 0 || year % 400 == 0)); */
+    return (!(year % 4) && ((year % 100) || !(year % 400)));
 }
 
 struct tm *gmtime_r(const time_t *timep, struct tm *r)
 {
-	time_t i;
-	register time_t work = *timep % (SPD);
-	r->tm_sec = work % 60;
-	work /= 60;
-	r->tm_min = work % 60;
-	r->tm_hour = work / 60;
-	work = *timep / (SPD);
-	r->tm_wday = (4 + work) % 7;
-	for (i = 1970;; ++i)
-	{
-		register time_t k = __isleap(i) ? 366 : 365;
-		if (work >= k)
-			work -= k;
-		else
-			break;
-	}
-	r->tm_year = i - 1900;
-	r->tm_yday = work;
-
-	r->tm_mday = 1;
-	if (__isleap(i) && (work > 58))
-	{
-		if (work == 59)
-			r->tm_mday = 2; /* 29.2. */
-		work -= 1;
-	}
-
-	for (i = 11; i && (__spm[i] > work); --i)
-		;
-	r->tm_mon = i;
-	r->tm_mday += work - __spm[i];
-	return r;
+    time_t i;
+    register time_t work = *timep % (SPD);
+    r->tm_sec = work % 60;
+    work /= 60;
+    r->tm_min = work % 60;
+    r->tm_hour = work / 60;
+    work = *timep / (SPD);
+    r->tm_wday = (4 + work) % 7;
+    for (i = 1970;; ++i)
+    {
+        register time_t k = __isleap(i) ? 366 : 365;
+        if (work >= k)
+            work -= k;
+        else
+            break;
+    }
+    r->tm_year = i - 1900;
+    r->tm_yday = work;
+
+    r->tm_mday = 1;
+    if (__isleap(i) && (work > 58))
+    {
+        if (work == 59)
+            r->tm_mday = 2; /* 29.2. */
+        work -= 1;
+    }
+
+    for (i = 11; i && (__spm[i] > work); --i)
+        ;
+    r->tm_mon = i;
+    r->tm_mday += work - __spm[i];
+    return r;
 }
 
 struct tm* localtime_r(const time_t* t, struct tm* r)
 {
-	time_t tmp;
-	struct timezone tz = {0};
-	gettimeofday(0, &tz);
-	timezone = tz.tz_minuteswest * 60L;
-	tmp = *t + timezone;
-	return gmtime_r(&tmp, r);
+    time_t tmp;
+    struct timezone tz = {0};
+    gettimeofday(0, &tz);
+    timezone = tz.tz_minuteswest * 60L;
+    tmp = *t + timezone;
+    return gmtime_r(&tmp, r);
 }
 
 struct tm* localtime(const time_t* t)
 {
-	static struct tm tmp;
-	return localtime_r(t, &tmp);
+    static struct tm tmp;
+    return localtime_r(t, &tmp);
 }
 
 time_t mktime(struct tm * const t)
 {
-	register time_t day;
-	register time_t i;
-	register time_t years = t->tm_year - 70;
-
-	if (t->tm_sec > 60)
-	{
-		t->tm_min += t->tm_sec / 60;
-		t->tm_sec %= 60;
-	}
-	if (t->tm_min > 60)
-	{
-		t->tm_hour += t->tm_min / 60;
-		t->tm_min %= 60;
-	}
-	if (t->tm_hour > 24)
-	{
-		t->tm_mday += t->tm_hour / 24;
-		t->tm_hour %= 24;
-	}
-	if (t->tm_mon > 12)
-	{
-		t->tm_year += t->tm_mon / 12;
-		t->tm_mon %= 12;
-	}
-	while (t->tm_mday > __spm[1 + t->tm_mon])
-	{
-		if (t->tm_mon == 1 && __isleap(t->tm_year + 1900))
-		{
-			--t->tm_mday;
-		}
-		t->tm_mday -= __spm[t->tm_mon];
-		++t->tm_mon;
-		if (t->tm_mon > 11)
-		{
-			t->tm_mon = 0;
-			++t->tm_year;
-		}
-	}
-
-	if (t->tm_year < 70)
-		return (time_t) -1;
-
-	/* Days since 1970 is 365 * number of years + number of leap years since 1970 */
-	day = years * 365 + (years + 1) / 4;
-
-	/* After 2100 we have to substract 3 leap years for every 400 years
-	 This is not intuitive. Most mktime implementations do not support
-	 dates after 2059, anyway, so we might leave this out for it's
-	 bloat. */
-	if (years >= 131)
-	{
-		years -= 131;
-		years /= 100;
-		day -= (years >> 2) * 3 + 1;
-		if ((years &= 3) == 3)
-			years--;
-		day -= years;
-	}
-
-	day += t->tm_yday = __spm[t->tm_mon] + t->tm_mday - 1 +
-			(__isleap(t->tm_year + 1900) & (t->tm_mon > 1));
-
-	/* day is now the number of days since 'Jan 1 1970' */
-	i = 7;
-	t->tm_wday = (day + 4) % i; /* Sunday=0, Monday=1, ..., Saturday=6 */
-
-	i = 24;
-	day *= i;
-	i = 60;
-	return ((day + t->tm_hour) * i + t->tm_min) * i + t->tm_sec;
+    register time_t day;
+    register time_t i;
+    register time_t years = t->tm_year - 70;
+
+    if (t->tm_sec > 60)
+    {
+        t->tm_min += t->tm_sec / 60;
+        t->tm_sec %= 60;
+    }
+    if (t->tm_min > 60)
+    {
+        t->tm_hour += t->tm_min / 60;
+        t->tm_min %= 60;
+    }
+    if (t->tm_hour > 24)
+    {
+        t->tm_mday += t->tm_hour / 24;
+        t->tm_hour %= 24;
+    }
+    if (t->tm_mon > 12)
+    {
+        t->tm_year += t->tm_mon / 12;
+        t->tm_mon %= 12;
+    }
+    while (t->tm_mday > __spm[1 + t->tm_mon])
+    {
+        if (t->tm_mon == 1 && __isleap(t->tm_year + 1900))
+        {
+            --t->tm_mday;
+        }
+        t->tm_mday -= __spm[t->tm_mon];
+        ++t->tm_mon;
+        if (t->tm_mon > 11)
+        {
+            t->tm_mon = 0;
+            ++t->tm_year;
+        }
+    }
+
+    if (t->tm_year < 70)
+        return (time_t) - 1;
+
+    /* Days since 1970 is 365 * number of years + number of leap years since 1970 */
+    day = years * 365 + (years + 1) / 4;
+
+    /* After 2100 we have to substract 3 leap years for every 400 years
+     This is not intuitive. Most mktime implementations do not support
+     dates after 2059, anyway, so we might leave this out for it's
+     bloat. */
+    if (years >= 131)
+    {
+        years -= 131;
+        years /= 100;
+        day -= (years >> 2) * 3 + 1;
+        if ((years &= 3) == 3)
+            years--;
+        day -= years;
+    }
+
+    day += t->tm_yday = __spm[t->tm_mon] + t->tm_mday - 1 +
+                        (__isleap(t->tm_year + 1900) & (t->tm_mon > 1));
+
+    /* day is now the number of days since 'Jan 1 1970' */
+    i = 7;
+    t->tm_wday = (day + 4) % i; /* Sunday=0, Monday=1, ..., Saturday=6 */
+
+    i = 24;
+    day *= i;
+    i = 60;
+    return ((day + t->tm_hour) * i + t->tm_min) * i + t->tm_sec;
 }
 
 static void num2str(char *c, int i)
 {
-	c[0] = i / 10 + '0';
-	c[1] = i % 10 + '0';
+    c[0] = i / 10 + '0';
+    c[1] = i % 10 + '0';
 }
 
 char *asctime_r(const struct tm *t, char *buf)
 {
-	/* "Wed Jun 30 21:49:08 1993\n" */
-	*(int*) buf = *(int*) (days + (t->tm_wday << 2));
-	*(int*) (buf + 4) = *(int*) (months + (t->tm_mon << 2));
-	num2str(buf + 8, t->tm_mday);
-	if (buf[8] == '0')
-		buf[8] = ' ';
-	buf[10] = ' ';
-	num2str(buf + 11, t->tm_hour);
-	buf[13] = ':';
-	num2str(buf + 14, t->tm_min);
-	buf[16] = ':';
-	num2str(buf + 17, t->tm_sec);
-	buf[19] = ' ';
-	num2str(buf + 20, (t->tm_year + 1900) / 100);
-	num2str(buf + 22, (t->tm_year + 1900) % 100);
-	buf[24] = '\n';
-	return buf;
+    /* "Wed Jun 30 21:49:08 1993\n" */
+    *(int*) buf = *(int*) (days + (t->tm_wday << 2));
+    *(int*) (buf + 4) = *(int*) (months + (t->tm_mon << 2));
+    num2str(buf + 8, t->tm_mday);
+    if (buf[8] == '0')
+        buf[8] = ' ';
+    buf[10] = ' ';
+    num2str(buf + 11, t->tm_hour);
+    buf[13] = ':';
+    num2str(buf + 14, t->tm_min);
+    buf[16] = ':';
+    num2str(buf + 17, t->tm_sec);
+    buf[19] = ' ';
+    num2str(buf + 20, (t->tm_year + 1900) / 100);
+    num2str(buf + 22, (t->tm_year + 1900) % 100);
+    buf[24] = '\n';
+    return buf;
 }
 
 char *asctime(const struct tm *timeptr)
 {
-	static char buf[25];
-	return asctime_r(timeptr, buf);
+    static char buf[25];
+    return asctime_r(timeptr, buf);
 }
 
 char *ctime(const time_t *timep)
 {
-	return asctime(localtime(timep));
+    return asctime(localtime(timep));
 }
 
 #ifdef RT_USING_DEVICE
 int gettimeofday(struct timeval *tp, void *ignore)
 {
-	time_t time;
-	rt_device_t device;
-
-	device = rt_device_find("rtc");
-	if (device != RT_NULL)
-	{
-		rt_device_control(device, RT_DEVICE_CTRL_RTC_GET_TIME, &time);
-		if (tp != RT_NULL)
-		{
-			tp->tv_sec = time;
-			tp->tv_usec = 0;
-		}
-
-		return time;
-	}
-
-	return 0;
+    time_t time;
+    rt_device_t device;
+
+    device = rt_device_find("rtc");
+    RT_ASSERT(device != RT_NULL);
+
+    rt_device_control(device, RT_DEVICE_CTRL_RTC_GET_TIME, &time);
+    if (tp != RT_NULL)
+    {
+        tp->tv_sec = time;
+        tp->tv_usec = 0;
+    }
+
+    return time;
 }
 #endif
 
diff --git a/components/libc/compilers/newlib/time.c b/components/libc/compilers/newlib/time.c
index 29c5c6cdd2ca818a9cb8ca3b0a1ea60f10a6a5d3..f099d51330da569b8b3f3bb1c53e57f222870d32 100644
--- a/components/libc/compilers/newlib/time.c
+++ b/components/libc/compilers/newlib/time.c
@@ -16,19 +16,16 @@ int gettimeofday(struct timeval *tp, void *ignore)
     rt_device_t device;
 
     device = rt_device_find("rtc");
-    if (device != RT_NULL)
-    {
-        rt_device_control(device, RT_DEVICE_CTRL_RTC_GET_TIME, &time);
-        if (tp != RT_NULL)
-        {
-            tp->tv_sec = time;
-            tp->tv_usec = 0;
-        }
+    RT_ASSERT(device != RT_NULL);
 
-        return time;
+    rt_device_control(device, RT_DEVICE_CTRL_RTC_GET_TIME, &time);
+    if (tp != RT_NULL)
+    {
+        tp->tv_sec = time;
+        tp->tv_usec = 0;
     }
 
-    return 0;
+    return time;
 }
 #endif