- signal strength and snr calculations code included, but not activate. log10 is missing

1 files changed, 52 insertions, 10 deletions

diff --git a/linux/drivers/media/dvb/frontends/dib3000mb.c b/linux/drivers/media/dvb/frontends/dib3000mb.c
index e93123e1b..1af977839 100644
--- a/linux/drivers/media/dvb/frontends/dib3000mb.c
+++ b/linux/drivers/media/dvb/frontends/dib3000mb.c
@@ -17,6 +17,8 @@
  *  Amaury Demol (ademol@dibcom.fr) from DiBcom for providing specs and driver
  *  sources, on which this driver (and the dvb-dibusb) are based.
  *
+ * $Id $Id: dib3000mb.c,v 1.8 2004/09/28 19:39:06 pmp Exp $$
+ * 
  * see Documentation/dvb/README.dibusb for more information
  * 
  */
@@ -569,8 +571,8 @@ static int dib3000mb_set_frontend(struct dib3000mb_state *state,
 		wr(DIB3000MB_REG_RESTART,DIB3000MB_RESTART_OFF);
 		
 		while ((search_state = dib3000mb_fe_read_search_status(state)) < 0);
-		
-		return search_state ? 0 : -EINVAL;
+		deb_info("search_state after autosearch %d\n",search_state);
+		return search_state  ? 0 : -EINVAL;
 	} else {
 		wr(DIB3000MB_REG_RESTART,DIB3000MB_RESTART_CTRL);
 		wr(DIB3000MB_REG_RESTART,DIB3000MB_RESTART_OFF);
@@ -697,26 +699,66 @@ static int dib3000mb_read_ber(struct dib3000mb_state *state,u32 *ber)
 		((rd(DIB3000MB_REG_BER_MSB) << 16) | rd(DIB3000MB_REG_BER_LSB) );
 	return 0;
 }
+/*
+ * Amaury:
+ * signal strength is measured with dBm (power compared to mW)
+ * the standard range is -90dBm(low power) to -10 dBm (strong power),
+ * but the calibration is done for -100 dBm to 0dBm
+ */
 
+#define DIB3000MB_AGC_REF_dBm		-14
+#define DIB3000MB_GAIN_SLOPE_dBm	100
+#define DIB3000MB_GAIN_DELTA_dBm	-2
 static int dib3000mb_read_signal_strength(struct dib3000mb_state *state, u16 *strength)
 {
-	*strength = rd(DIB3000MB_REG_SIGNAL_POWER);
+/* TODO log10 
+	u16 sigpow = rd(DIB3000MB_REG_SIGNAL_POWER), 
+		n_agc_power = rd(DIB3000MB_REG_AGC_POWER),
+		rf_power = rd(DIB3000MB_REG_RF_POWER);
+	double rf_power_dBm, ad_power_dBm, minar_power_dBm;
+	
+	if (n_agc_power == 0 )
+		n_agc_power = 1 ;
+
+	ad_power_dBm    = 10 * log10 ( (float)n_agc_power / (float)(1<<16) );
+	minor_power_dBm = ad_power_dBm - DIB3000MB_AGC_REF_dBm;
+	rf_power_dBm = (-DIB3000MB_GAIN_SLOPE_dBm * (float)rf_power / (float)(1<<16) + 
+			DIB3000MB_GAIN_DELTA_dBm) + minor_power_dBm;
+	// relative rf_power 
+	*strength = (u16) ((rf_power_dBm + 100) / 100 * 0xffff);
+*/
+	*strength = rd(DIB3000MB_REG_SIGNAL_POWER) * 0xffff / 0x170;
 	return 0;
 }
 
+/*
+ * Amaury: 
+ * snr is the signal quality measured in dB.
+ * snr = 10*log10(signal power / noise power)
+ * the best quality is near 35dB (cable transmission & good modulator)
+ * the minimum without errors depend of transmission parameters
+ * some indicative values are given in en300744 Annex A
+ * ex : 16QAM 2/3 (Gaussian)  = 11.1 dB
+ *
+ * If SNR is above 20dB, BER should be always 0.
+ * choose 0dB as the minimum
+ */
 static int dib3000mb_read_snr(struct dib3000mb_state *state,u16 *snr)
 {
 	short sigpow = rd(DIB3000MB_REG_SIGNAL_POWER);
 	int icipow = ((rd(DIB3000MB_REG_NOISE_POWER_MSB) & 0xff) << 16) |
 		rd(DIB3000MB_REG_NOISE_POWER_LSB);
+/*
+	float snr_dBm=0;
+
+	if (sigpow > 0 && icipow > 0)
+		snr_dBm = 10.0 * log10( (float) (sigpow<<8) / (float)icipow )  ;
+	else if (sigpow > 0)
+		snr_dBm = 35;
 	
-	deb_info("sigpow: %d, icipow: %d\n",sigpow,icipow);
-	
-	if (sigpow > 0 && icipow > 0) {
-		*snr = (sigpow << 8 / icipow);
-	} else 
-		snr = 0;
-		
+	*snr = (u16) ((snr_dBm / 35) * 0xffff);
+*/
+	*snr = (sigpow<<8) / (icipow > 0 ? icipow : 1);
 	return 0;
 }