[lcd4linux @ 2003-06-22 19:31:24 by reinelt]

added dvb.c dvb.h

1 files changed, 98 insertions, 0 deletions

diff --git a/dvb.c b/dvb.c
new file mode 100644
index 0000000..be01168
--- /dev/null
+++ b/dvb.c
@@ -0,0 +1,98 @@
+/* $Id $
+ *
+ * DVB specific functions
+ *
+ * Copyright 2003 by Michael Reinelt (reinelt@eunet.at)
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2, or (at your option)
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ *
+ *
+ * $Log
+ */
+
+/* 
+ * exported functions:
+ *
+ * DVB (int *strength, int *snr)
+ *   returns 0 if ok, -1 if error
+ *   sets *strength to the signal strength
+ *   sets *snr to the signal/noise ratio
+ *
+ */
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <time.h>
+#include <sys/ioctl.h>
+#include <sys/types.h>
+#include <linux/dvb/frontend.h>
+
+#include "debug.h"
+#include "dvb.h"
+#include "filter.h"
+
+int DVB (double *strength, double *snr)
+{
+  static time_t now=0;
+  static int fd=-2;
+  static double strength0=0.0;
+  static double snr0=0.0;
+  
+  unsigned short raw_strength;
+  unsigned short raw_snr;
+
+  *strength=strength0;
+  *snr=snr0;
+
+  if (fd==-1) return -1;
+  
+  if (time(NULL)==now) return 0;
+  time(&now);
+
+  if (fd==-2) {
+    fd = open("/dev/dvb/adapter0/frontend0", O_RDONLY);
+    if (fd==-1) {
+      error ("open(/dev/dvb/adapter0/frontend0) failed: %s", strerror(errno));
+      return -1;
+    }
+    debug ("open (/dev/dvb/adapter0/frontend0)=%d", fd);
+  }
+
+  if (ioctl(fd, FE_READ_SIGNAL_STRENGTH, &raw_strength)) {
+    error("ioctl(FE_READ_SIGNAL_STRENGTH) failed: %s", strerror(errno));
+    fd=-1;
+    return -1;
+  }
+
+  if (ioctl(fd, FE_READ_SNR, &raw_snr)) {
+    error("ioctl(FE_READ_SNR) failed: %s", strerror(errno));
+    fd=-1;
+    return -1;
+  }
+
+  // Normalize to 1.0
+  strength0=raw_strength/65535.0;
+  snr0=raw_snr/65535.0;
+
+  *strength=strength0;
+  *snr=snr0;
+
+  return 0;
+}
+