diff --git NuttX/nuttx/fs/vfs/fs_lseek.c NuttX/nuttx/fs/vfs/fs_lseek.c
index be74239eca..bea398c0a3 100644
--- NuttX/nuttx/fs/vfs/fs_lseek.c
+++ NuttX/nuttx/fs/vfs/fs_lseek.c
@@ -99,7 +99,7 @@ off_t file_seek(FAR struct file *filep, off_t offset, int whence)
         {
           case SEEK_CUR:
             offset += filep->f_pos;
-
+            /* FALLTHROUGH */
           case SEEK_SET:
             if (offset >= 0)
               {
diff --git NuttX/nuttx/libc/stdio/lib_sscanf.c NuttX/nuttx/libc/stdio/lib_sscanf.c
index 0bc413295b..f2b9a8d4e8 100644
--- NuttX/nuttx/libc/stdio/lib_sscanf.c
+++ NuttX/nuttx/libc/stdio/lib_sscanf.c
@@ -417,6 +417,7 @@ int vsscanf(FAR const char *buf, FAR const char *fmt, va_list ap)
                     default:
                     case 'd':
                       sign = true;
+                      /* FALLTHROUGH */
                     case 'u':
                       base = 10;
                       break;
diff --git NuttX/nuttx/libc/stdlib/lib_strtod.c NuttX/nuttx/libc/stdlib/lib_strtod.c
index 62da9e0f6e..af830abf50 100644
--- NuttX/nuttx/libc/stdlib/lib_strtod.c
+++ NuttX/nuttx/libc/stdlib/lib_strtod.c
@@ -113,8 +113,10 @@ double strtod(FAR const char *str, FAR char **endptr)
     {
     case '-':
       negative = 1; /* Fall through to increment position */
+      /* FALLTHROUGH */
     case '+':
       p++;
+      /* FALLTHROUGH */
     default:
       break;
     }
@@ -175,8 +177,10 @@ double strtod(FAR const char *str, FAR char **endptr)
         {
         case '-':
           negative = 1;   /* Fall through to increment pos */
+          /* FALLTHROUGH */
         case '+':
           p++;
+          /* FALLTHROUGH */
         default:
           break;
         }
diff --git NuttX/nuttx/libc/stdlib/lib_strtof.c NuttX/nuttx/libc/stdlib/lib_strtof.c
index 467842f4e6..6571e2d77e 100644
--- NuttX/nuttx/libc/stdlib/lib_strtof.c
+++ NuttX/nuttx/libc/stdlib/lib_strtof.c
@@ -115,8 +115,10 @@ float strtof(FAR const char *str, FAR char **endptr)
     {
     case '-':
       negative = 1; /* Fall through to increment position */
+      /* FALLTHROUGH */
     case '+':
       p++;
+      /* FALLTHROUGH */
     default:
       break;
     }
@@ -177,8 +179,10 @@ float strtof(FAR const char *str, FAR char **endptr)
         {
         case '-':
           negative = 1;   /* Fall through to increment pos */
+          /* FALLTHROUGH */
         case '+':
           p++;
+          /* FALLTHROUGH */
         default:
           break;
         }
diff --git NuttX/nuttx/libc/stdlib/lib_strtold.c NuttX/nuttx/libc/stdlib/lib_strtold.c
index c306392cec..ac9368e893 100644
--- NuttX/nuttx/libc/stdlib/lib_strtold.c
+++ NuttX/nuttx/libc/stdlib/lib_strtold.c
@@ -113,8 +113,10 @@ long double strtold(FAR const char *str, FAR char **endptr)
     {
     case '-':
       negative = 1; /* Fall through to increment position */
+      /* FALLTHROUGH */
     case '+':
       p++;
+      /* FALLTHROUGH */
     default:
       break;
     }
@@ -175,8 +177,10 @@ long double strtold(FAR const char *str, FAR char **endptr)
         {
         case '-':
           negative = 1;   /* Fall through to increment pos */
+          /* FALLTHROUGH */
         case '+':
           p++;
+          /* FALLTHROUGH */
         default:
           break;
         }
diff --git NuttX/nuttx/libc/stdio/lib_dtoa.c NuttX/nuttx/libc/stdio/lib_dtoa.c
index 8ddc3bfd35..0cc3b48fdd 100644
--- NuttX/nuttx/libc/stdio/lib_dtoa.c
+++ NuttX/nuttx/libc/stdio/lib_dtoa.c
@@ -591,6 +591,7 @@ static int cmp(Bigint * a, Bigint * b)
           break;
         }
     }
+
   return 0;
 }

@@ -784,6 +785,7 @@ static Bigint *d2b(double d, int *e, int *bits)
     }
   while (!x[i])
     --i;
+
   b->wds = i + 1;
 #endif
   if (de)
@@ -817,11 +819,6 @@ static const double bigtens[] =
   1e16, 1e32, 1e64, 1e128, 1e256
 };

-static const double tinytens[] =
-{
-  1e-16, 1e-32, 1e-64, 1e-128, 1e-256
-};
-
 #  define n_bigtens 5
 #else
 static const double bigtens[] =
@@ -829,11 +826,6 @@ static const double bigtens[] =
   1e16, 1e32
 };

-static const double tinytens[] =
-{
-  1e-16, 1e-32
-};
-
 #  define n_bigtens 2
 #endif

@@ -849,12 +841,14 @@ static int quorem(Bigint * b, Bigint * S)
 #endif

   n = S->wds;
+
 #ifdef CONFIG_DEBUG_LIB
   if (b->wds > n)
     {
       lerr("ERROR: oversize b in quorem\n");
     }
 #endif
+
   if (b->wds < n)
     {
       return 0;
@@ -865,17 +859,19 @@ static int quorem(Bigint * b, Bigint * S)
   bx = b->x;
   bxe = bx + n;
   q = *bxe / (*sxe + 1);        /* ensure q <= true quotient */
+
 #ifdef CONFIG_DEBUG_LIB
   if (q > 9)
-   {
-     lerr("ERROR: oversized quotient in quorem\n");
-   }
+    {
+      lerr("ERROR: oversized quotient in quorem\n");
+    }
 #endif

   if (q)
     {
       borrow = 0;
       carry = 0;
+
       do
         {
 #ifdef Pack_32
@@ -912,6 +908,7 @@ static int quorem(Bigint * b, Bigint * S)
           b->wds = n;
         }
     }
+
   if (cmp(b, S) >= 0)
     {
       q++;
@@ -919,6 +916,7 @@ static int quorem(Bigint * b, Bigint * S)
       carry = 0;
       bx = b->x;
       sx = S->x;
+
       do
         {
 #ifdef Pack_32
@@ -943,12 +941,14 @@ static int quorem(Bigint * b, Bigint * S)
 #endif
         }
       while (sx <= sxe);
+
       bx = b->x;
       bxe = bx + n;
       if (!*bxe)
         {
           while (--bxe > bx && !*bxe)
             --n;
+
           b->wds = n;
         }
     }
@@ -1041,7 +1041,8 @@ char *__dtoa(double d, int mode, int ndigits, int *decpt, int *sign, char **rve)

   if (word0(d) & Sign_bit)
     {
-      /* set sign for everything, including 0's and NaNs */
+      /* Set sign for everything, including 0's and NaNs */
+
       *sign = 1;
       word0(d) &= ~Sign_bit;    /* clear sign bit */
     }
@@ -1058,6 +1059,7 @@ char *__dtoa(double d, int mode, int ndigits, int *decpt, int *sign, char **rve)
 #endif
     {
       /* Infinity or NaN */
+
       *decpt = 9999;
       s =
 #ifdef IEEE_Arith
@@ -1076,6 +1078,7 @@ char *__dtoa(double d, int mode, int ndigits, int *decpt, int *sign, char **rve)
       return s;
     }
 #endif
+
   if (!d)
     {
       *decpt = 1;
@@ -1190,7 +1193,7 @@ char *__dtoa(double d, int mode, int ndigits, int *decpt, int *sign, char **rve)

     case 2:
       leftright = 0;
-      /* no break */
+      /* FALLTHROUGH */
     case 4:
       if (ndigits <= 0)
         {
@@ -1202,7 +1205,7 @@ char *__dtoa(double d, int mode, int ndigits, int *decpt, int *sign, char **rve)

     case 3:
       leftright = 0;
-      /* no break */
+      /* FALLTHROUGH */
     case 5:
       i = ndigits + k + 1;
       ilim = i;
@@ -1241,7 +1244,8 @@ char *__dtoa(double d, int mode, int ndigits, int *decpt, int *sign, char **rve)

           if (j & Bletch)
             {
-              /* prevent overflows */
+              /* Prevent overflows */
+
               j &= Bletch - 1;
               d /= bigtens[n_bigtens - 1];
               ieps++;
@@ -1292,8 +1296,10 @@ char *__dtoa(double d, int mode, int ndigits, int *decpt, int *sign, char **rve)
           d -= 5.;
           if (d > eps)
             goto one_digit;
+
           if (d < -eps)
             goto no_digits;
+
           goto fast_failed;
         }

@@ -1357,6 +1363,7 @@ char *__dtoa(double d, int mode, int ndigits, int *decpt, int *sign, char **rve)
 #ifndef No_leftright
         }
 #endif
+
     fast_failed:
       s = s0;
       d = d2;
@@ -1386,8 +1393,10 @@ char *__dtoa(double d, int mode, int ndigits, int *decpt, int *sign, char **rve)
         {
           L = (int)(d / ds);
           d -= L * ds;
+
 #ifdef Check_FLT_ROUNDS
           /* If FLT_ROUNDS == 2, L will usually be high by 1 */
+
           if (d < 0)
             {
               L--;
@@ -1411,6 +1420,7 @@ char *__dtoa(double d, int mode, int ndigits, int *decpt, int *sign, char **rve)

                   ++*s++;
                 }
+
               break;
             }

@@ -1500,6 +1510,7 @@ char *__dtoa(double d, int mode, int ndigits, int *decpt, int *sign, char **rve)
       if (!word1(d) && !(word0(d) & Bndry_mask) && word0(d) & Exp_mask)
         {
           /* The special case */
+
           b2 += Log2P;
           s2 += Log2P;
           spec_case = 1;
diff --git NuttX/nuttx/drivers/mmcsd/mmcsd_spi.c NuttX/nuttx/drivers/mmcsd/mmcsd_spi.c
index 2a4cdee73d..c50c3b1456 100644
--- NuttX/nuttx/drivers/mmcsd/mmcsd_spi.c
+++ b/drivers/mmcsd/mmcsd_spi.c
@@ -326,7 +326,9 @@ static const struct mmcsd_cmdinfo_s g_cmd0   = {CMD0,   MMCSD_CMDRESP_R1, 0x95};
 static const struct mmcsd_cmdinfo_s g_cmd1   = {CMD1,   MMCSD_CMDRESP_R1, 0xff};
 static const struct mmcsd_cmdinfo_s g_cmd8   = {CMD8,   MMCSD_CMDRESP_R7, 0x87};
 static const struct mmcsd_cmdinfo_s g_cmd9   = {CMD9,   MMCSD_CMDRESP_R1, 0xff};
+#if 0 /*not used */
 static const struct mmcsd_cmdinfo_s g_cmd10  = {CMD10,  MMCSD_CMDRESP_R1, 0xff};
+#endif
 static const struct mmcsd_cmdinfo_s g_cmd12  = {CMD12,  MMCSD_CMDRESP_R1, 0xff};
 static const struct mmcsd_cmdinfo_s g_cmd16  = {CMD16,  MMCSD_CMDRESP_R1, 0xff};
 static const struct mmcsd_cmdinfo_s g_cmd17  = {CMD17,  MMCSD_CMDRESP_R1, 0xff};