diff --git a/src/ppi.c b/src/ppi.c
index 61bd55ab..08dc336f 100644
--- a/src/ppi.c
+++ b/src/ppi.c
@@ -16,13 +16,10 @@
  * along with this program. If not, see <http://www.gnu.org/licenses/>.
  */
 
-
 #if !defined(WIN32)
-
 #include <ac_cfg.h>
 
 #if HAVE_PARPORT
-
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -31,11 +28,11 @@
 #include <errno.h>
 
 #if defined(__FreeBSD__) || defined(__FreeBSD_kernel__)
-# include "freebsd_ppi.h"
+#include "freebsd_ppi.h"
 #elif defined(__linux__)
-# include "linux_ppdev.h"
-#elif defined(__sun__) || defined(__sun) /* Solaris */
-# include "solaris_ecpp.h"
+#include "linux_ppdev.h"
+#elif defined(__sun__) || defined(__sun)        // Solaris
+#include "solaris_ecpp.h"
 #endif
 
 #include "avrdude.h"
@@ -49,46 +46,42 @@ enum {
   PPI_SHADOWREAD
 };
 
-static int ppi_shadow_access(const union filedescriptor *fdp, int reg,
-			     unsigned char *v, unsigned char action)
-{
+static int ppi_shadow_access(const union filedescriptor *fdp, int reg, unsigned char *v, unsigned char action) {
   int shadow_num;
 
   switch (reg) {
-    case PPIDATA:
-      shadow_num = 0;
-      break;
-    case PPICTRL:
-      shadow_num = 1;
-      break;
-    case PPISTATUS:
-      shadow_num = 2;
-      break;
-    default:
-      pmsg_error("invalid register=%d\n", reg);
-      return -1;
-      break;
+  case PPIDATA:
+    shadow_num = 0;
+    break;
+  case PPICTRL:
+    shadow_num = 1;
+    break;
+  case PPISTATUS:
+    shadow_num = 2;
+    break;
+  default:
+    pmsg_error("invalid register=%d\n", reg);
+    return -1;
+    break;
   }
 
   switch (action) {
-    case PPI_SHADOWREAD:
-      *v = cx->ppi_shadow[shadow_num];
-      break;
-    case PPI_READ:
-      DO_PPI_READ(fdp->ifd, reg, v);
-      cx->ppi_shadow[shadow_num]=*v;
-      break;
-    case PPI_WRITE:
-      cx->ppi_shadow[shadow_num]=*v;
-      DO_PPI_WRITE(fdp->ifd, reg, v);
-      break;
+  case PPI_SHADOWREAD:
+    *v = cx->ppi_shadow[shadow_num];
+    break;
+  case PPI_READ:
+    DO_PPI_READ(fdp->ifd, reg, v);
+    cx->ppi_shadow[shadow_num] = *v;
+    break;
+  case PPI_WRITE:
+    cx->ppi_shadow[shadow_num] = *v;
+    DO_PPI_WRITE(fdp->ifd, reg, v);
+    break;
   }
   return 0;
 }
 
-/*
- * set the indicated bit of the specified register.
- */
+// Set the indicated bit of the specified register
 int ppi_set(const union filedescriptor *fdp, int reg, int bit) {
   unsigned char v;
   int rc;
@@ -97,16 +90,13 @@ int ppi_set(const union filedescriptor *fdp, int reg, int bit) {
   v |= bit;
   rc |= ppi_shadow_access(fdp, reg, &v, PPI_WRITE);
 
-  if (rc)
+  if(rc)
     return -1;
 
   return 0;
 }
 
-
-/*
- * clear the indicated bit of the specified register.
- */
+// Clear the indicated bit of the specified register
 int ppi_clr(const union filedescriptor *fdp, int reg, int bit) {
   unsigned char v;
   int rc;
@@ -115,16 +105,13 @@ int ppi_clr(const union filedescriptor *fdp, int reg, int bit) {
   v &= ~bit;
   rc |= ppi_shadow_access(fdp, reg, &v, PPI_WRITE);
 
-  if (rc)
+  if(rc)
     return -1;
 
   return 0;
 }
 
-
-/*
- * get the indicated bit of the specified register.
- */
+// Get the indicated bit of the specified register
 int ppi_get(const union filedescriptor *fdp, int reg, int bit) {
   unsigned char v;
   int rc;
@@ -132,15 +119,13 @@ int ppi_get(const union filedescriptor *fdp, int reg, int bit) {
   rc = ppi_shadow_access(fdp, reg, &v, PPI_READ);
   v &= bit;
 
-  if (rc)
+  if(rc)
     return -1;
 
-  return v; /* v == bit */
+  return v;                     // v == bit
 }
 
-/*
- * toggle the indicated bit of the specified register.
- */
+// Toggle the indicated bit of the specified register
 int ppi_toggle(const union filedescriptor *fdp, int reg, int bit) {
   unsigned char v;
   int rc;
@@ -149,31 +134,26 @@ int ppi_toggle(const union filedescriptor *fdp, int reg, int bit) {
   v ^= bit;
   rc |= ppi_shadow_access(fdp, reg, &v, PPI_WRITE);
 
-  if (rc)
+  if(rc)
     return -1;
 
   return 0;
 }
 
-
-/*
- * get all bits of the specified register.
- */
+// Get all bits of the specified register
 int ppi_getall(const union filedescriptor *fdp, int reg) {
   unsigned char v;
   int rc;
 
   rc = ppi_shadow_access(fdp, reg, &v, PPI_READ);
 
-  if (rc)
+  if(rc)
     return -1;
 
-  return v; /* v == bit */
+  return v;                     // v == bit
 }
 
-/*
- * set all bits of the specified register to val.
- */
+// Set all bits of the specified register to val
 int ppi_setall(const union filedescriptor *fdp, int reg, int val) {
   unsigned char v;
   int rc;
@@ -181,43 +161,36 @@ int ppi_setall(const union filedescriptor *fdp, int reg, int val) {
   v = val;
   rc = ppi_shadow_access(fdp, reg, &v, PPI_WRITE);
 
-  if (rc)
+  if(rc)
     return -1;
 
   return 0;
 }
 
-
 void ppi_open(const char *port, union filedescriptor *fdp) {
   int fd;
   unsigned char v;
 
   fd = open(port, O_RDWR);
-  if (fd < 0) {
+  if(fd < 0) {
     pmsg_ext_error("cannot open port %s: %s\n", port, strerror(errno));
     fdp->ifd = -1;
     return;
   }
 
-  ppi_claim (fd);
+  ppi_claim(fd);
 
-  /*
-   * Initialize shadow registers
-   */
-
-  ppi_shadow_access (fdp, PPIDATA, &v, PPI_READ);
-  ppi_shadow_access (fdp, PPICTRL, &v, PPI_READ);
-  ppi_shadow_access (fdp, PPISTATUS, &v, PPI_READ);
+  // Initialize shadow registers
+  ppi_shadow_access(fdp, PPIDATA, &v, PPI_READ);
+  ppi_shadow_access(fdp, PPICTRL, &v, PPI_READ);
+  ppi_shadow_access(fdp, PPISTATUS, &v, PPI_READ);
 
   fdp->ifd = fd;
 }
 
-
 void ppi_close(const union filedescriptor *fdp) {
-  ppi_release (fdp->ifd);
+  ppi_release(fdp->ifd);
   close(fdp->ifd);
 }
-
-#endif /* HAVE_PARPORT */
-
-#endif /* !WIN32 */
+#endif                          // HAVE_PARPORT
+#endif                          // ! WIN32