Eliminate a couple more uses of printf() within the OS. There are several more.

drivers/contactless/mfrc522.c

@@ -1285,13 +1285,16 @@ void mfrc522_init(FAR struct mfrc522_dev_s *dev)
 
 int mfrc522_selftest(FAR struct mfrc522_dev_s *dev)
 {
-  uint8_t i;
-  uint8_t result[64];
   uint8_t zeros[25] = {0, 0, 0, 0, 0,
                        0, 0, 0, 0, 0,
                        0, 0, 0, 0, 0,
                        0, 0, 0, 0, 0,
                        0, 0, 0, 0, 0};
+  char outbuf[3 * 8 + 1]
+  uint8_t result[64];
+  int i;
+  int j;
+  int k;
 
   /* Execute a software reset */
 
@@ -1347,14 +1350,15 @@ int mfrc522_selftest(FAR struct mfrc522_dev_s *dev)
   mfrc522_writeu8(dev, MFRC522_AUTOTEST_REG, 0x00);
 
   mfrc522info("Self Test Result:\n");
-  for (i = 1; i <= 64; i++)
-    {
-      printf("0x%02X ", result[i - 1]);
 
-      if ((i % 8) == 0)
+  for (i = 0; i < 64; i += 8)
+    {
+      for (j = 0; k = 0; j < 8; j++, k += 3)
         {
-          printf("\n");
+          (void)sprintf(&outbuf[k], " %02x", result[i + j]);
         }
+
+      mfrc522info("  %02x:%s\n", i, outbuf);
     }
 
   mfrc522info("Done!\n");

drivers/mtd/smart.c

@@ -3618,6 +3618,8 @@ retry:
         ferr("ERROR: Program bug!  Expected a free sector, free=%d\n", dev->freesectors);
         for (x = 0; x < dev->neraseblocks; x++)
           {
+            /* REVISIT:  Use of printf is not permitted within the OS */
+
             printf("%d ", dev->freecount[x]);
           }
 

drivers/wireless/cc1101.c

@@ -900,33 +900,42 @@ int cc1101_checkpart(struct cc1101_dev_s *dev)
  * Description:
  *   Dump the specified range of registers to the syslog.
  *
- *   WARNING:  Uses around 200 bytes of stack!
+ *   WARNING:  Uses around 75 bytes of stack!
  *
  ****************************************************************************/
 
 void cc1101_dumpregs(struct cc1101_dev_s *dev, uint8_t addr, uint8_t length)
 {
-  char outbuf[3 * 48];
-  uint8_t regbuf[48];
+  char outbuf[3 * 16 + 1];
+  uint8_t regbuf[16];
+  int readsize;
+  int remaining;
   int i;
   int j;
 
-  DEBUGASSERT(length < 48);
-
-  /* Read the registers into a buffer */
-
-  cc1101_access(dev, addr, (FAR uint8_t *)regbuf, length);
-
-  /* Format the output data */
-
-  for (i = 0, j = 0; i < length; i++, j += 3)
+  for (remaining = length; remaining > 0; remaining -= 16, addr += 16)
     {
-      (void)sprintf(&outbuf[j], "%02x ", regbuf[i]);
+      /* Read up to 16 registers into a buffer */
+
+      readsize = remaining;
+      if (readsize > 16)
+        {
+          readsize = 16;
+        }
+
+      cc1101_access(dev, addr, (FAR uint8_t *)regbuf, readsize);
+
+      /* Format the output data */
+
+      for (i = 0, j = 0; i < readsize; i++, j += 3)
+        {
+          (void)sprintf(&outbuf[j], " %02x", regbuf[i]);
+        }
+
+      /* Dump the formatted data to the syslog output */
+
+      wlinfo("CC1101[%2x]:%s\n", addr, outbuf);
     }
-
-  /* Dump the formatted data to the syslog output */
-
-  wlinfo("CC1101[%2x]: %s\n", addr, outbuf);
 }
 
 /****************************************************************************

drivers/wireless/ieee802154/at86rf23x/at86rf23x.c

@@ -1288,18 +1288,18 @@ static int at86rf23x_interrupt(int irq, FAR void *context, FAR void *arg)
 static int at86rf23x_regdump(FAR struct at86rf23x_dev_s *dev)
 {
   uint32_t i;
-  char buf[4+16*3+2+1];
+  char buf[4 + 16 * 3 + 2 + 1];
   int len=0;
 
-  printf("RF23X regs:\n");
+  wlinfo("RF23X regs:\n");
 
-  for (i=0;i<0x30;i++)
+  for (i = 0; i < 0x30; i++)
     {
       /* First row and every 15 regs */
 
       if ((i & 0x0f) == 0)
        {
-         len = sprintf(buf, "%02x: ",i&0xFF);
+         len = sprintf(buf, "%02x: ", i & 0xFF);
        }
 
       /* Print the register value */
@@ -1310,10 +1310,10 @@ static int at86rf23x_regdump(FAR struct at86rf23x_dev_s *dev)
        * debug message.
        */
 
-      if ((i&15) == 15 || i == 0x2f)
+      if ((i & 15) == 15 || i == 0x2f)
         {
-          sprintf(buf+len, "\n");
-          printf("%s",buf);
+          sprintf(buf + len, "\n");
+          wlinfo("%s" ,buf);q
         }
     }