[Lcd4linux-devel] sending udp packets on HD44780 keypresses

[Reinhard T. <sir...@ta...>]

In our appliance, we need some way to access the buttons near our lcd
display. Luckily, we found that in drv_HD_LCM162_timer, there is already
some checking done fore keypresses. So all I needed to to was to call a
function which sends some udp packages. Obviously, this only works on
LCM162 devices. Oh well...


The patch I use for that is included below. There are some unresolved
problems with it:

  - the portnumber (and perhaps the hostname) should be configurable
  - the format string could be configurable
  - documentation is lacking
  
what do you think about this patch? perhaps it could be integrated
better with the GPIO or some other driver, but I don't understand the
code enough.

As said, we needed a simple solution for accessing the buttons on our
LCM162 display. would be great if this patch could be merged in a more
generic form...


=== modified file 'drv_HD44780.c'
--- drv_HD44780.c	2006-08-10 20:40:46 +0000
+++ drv_HD44780.c	2006-10-02 12:34:14 +0000
@@ -316,6 +316,13 @@
 #include "drv_generic_i2c.h"
 #endif
 
+
+/* extra includes for sending udp */
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <netdb.h>
+
 static char Name[] = "HD44780";
 
 static int Bus;
@@ -1197,6 +1204,42 @@
 }
 
 
+static void send_keypress_via_udp(int keynum, int updown) {
+  int sock;
+  struct sockaddr_in name;
+  struct hostent *hostinfo;
+  char *msg[16];
+
+  /* Create the socket. */
+  sock = socket (PF_INET, SOCK_DGRAM, 0);
+  if (sock < 0) {
+    debug("fail to setup sockent: %m");
+    return;
+  }
+
+  name.sin_family = AF_INET;
+  name.sin_port = htons (11223);
+  name.sin_addr.s_addr = htonl(INADDR_ANY);
+  hostinfo = gethostbyname("localhost");
+  
+  if (hostinfo == NULL) {
+    debug ("gethostbyname on localhost failed. WTF?!");
+    return;
+  }
+
+  snprintf((char *)msg, 16, "key %d state %d\n", keynum, updown);
+
+  name.sin_addr = *(struct in_addr *) hostinfo->h_addr;
+  sendto(sock, msg, 16, 0,
+	 (struct sockaddr *) &name, sizeof name);
+
+  close(sock);
+
+  return;
+}
+
+
+
 static void drv_HD_LCM162_timer(void __attribute__ ((unused)) * notused)
 {
     static unsigned char data = 0x00;
@@ -1222,10 +1265,10 @@
 	updown = (data & mask6 ? 1 : 0);
 
 	debug("key %d press %d", keynum, updown);
+	send_keypress_via_udp(keynum, updown);
     }
 }
 
-
 static int drv_HD_start(const char *section, const int quiet)
 {
     char *model, *size, *bus;


-- 
Gruesse/greetings,
Reinhard Tartler, KeyID 945348A4