driver: tejeez's no-mod direct sampling

include/tuner_r82xx.h

@@ -115,5 +115,6 @@ int r82xx_standby(struct r82xx_priv *priv);
 int r82xx_init(struct r82xx_priv *priv);
 int r82xx_set_freq(struct r82xx_priv *priv, uint32_t freq);
 int r82xx_set_gain(struct r82xx_priv *priv, int set_manual_gain, int gain);
+int r82xx_set_nomod(struct r82xx_priv *priv);
 
 #endif

src/librtlsdr.c

@@ -1138,13 +1138,36 @@ int rtlsdr_set_direct_sampling(rtlsdr_dev_t *dev, int on)
 	if (!dev)
 		return -1;
 
-	if (on) {
+	/* set up normal direct sampling */
+	if (on == 1 || on == 2) {
 		if (dev->tuner && dev->tuner->exit) {
 			rtlsdr_set_i2c_repeater(dev, 1);
 			r = dev->tuner->exit(dev);
 			rtlsdr_set_i2c_repeater(dev, 0);
 		}
+	}
 
+	/* set up no-mod direct sampling */
+	if (on == 3 && dev->tuner) {
+		if (dev->tuner_type == RTLSDR_TUNER_E4000) {
+			fprintf(stderr, "Tuning E4000 to 3708 MHz\n");
+			rtlsdr_set_i2c_repeater(dev, 1);
+			dev->tuner->init(dev);
+			dev->tuner->set_freq(dev, 3708000000u);
+			e4000_set_bw(dev, 15000000);
+			rtlsdr_set_i2c_repeater(dev, 0);
+		}
+		if (dev->tuner_type == RTLSDR_TUNER_R820T) {
+			rtlsdr_dev_t* devt = (rtlsdr_dev_t*)dev;
+			rtlsdr_set_i2c_repeater(dev, 1);
+			dev->tuner->init(dev);
+			r82xx_set_nomod(&devt->r82xx_p);
+			rtlsdr_set_i2c_repeater(dev, 0);
+		}
+	}
+
+	/* common to all direct modes */
+	if (on) {
 		/* disable Zero-IF mode */
 		r |= rtlsdr_demod_write_reg(dev, 1, 0xb1, 0x1a, 1);
 
@@ -1155,11 +1178,14 @@ int rtlsdr_set_direct_sampling(rtlsdr_dev_t *dev, int on)
 		r |= rtlsdr_demod_write_reg(dev, 0, 0x08, 0x4d, 1);
 
 		/* swap I and Q ADC, this allows to select between two inputs */
-		r |= rtlsdr_demod_write_reg(dev, 0, 0x06, (on > 1) ? 0x90 : 0x80, 1);
+		r |= rtlsdr_demod_write_reg(dev, 0, 0x06, (on == 2) ? 0x90 : 0x80, 1);
 
 		fprintf(stderr, "Enabled direct sampling mode, input %i\n", on);
 		dev->direct_sampling = on;
-	} else {
+	}
+
+	/* disable direct sampling */
+	if (!on) {
 		if (dev->tuner && dev->tuner->init) {
 			rtlsdr_set_i2c_repeater(dev, 1);
 			r |= dev->tuner->init(dev);

src/tuner_r82xx.c

@@ -783,7 +783,20 @@ static int r82xx_set_tv_standard(struct r82xx_priv *priv,
 		flt_ext_widest = 0x00;	/* r15[7]: flt_ext_wide off */
 		polyfil_cur = 0x60;	/* r25[6:5]:min */
 	} else {
-		if (bw <= 6) {
+		if (bw < 6) {
+			/* narrowest bandwidth? */
+			if_khz = 3570;
+			filt_cal_lo = 56000;	/* 52000->56000 */
+			filt_gain = 0x10;	/* +3db, 6mhz on */
+			img_r = 0x00;		/* image negative */
+			filt_q = 0x10;		/* r10[4]:low q(1'b1) */
+			hp_cor = 0x6a;		/* 1.7m disable, +2cap, 1.25mhz */
+			ext_enable = 0x60;	/* r30[6]=1 ext enable; r30[5]:1 ext at lna max-1 */
+			loop_through = 0x00;	/* r5[7], lt on */
+			lt_att = 0x00;		/* r31[7], lt att enable */
+			flt_ext_widest = 0x00;	/* r15[7]: flt_ext_wide off */
+			polyfil_cur = 0x60;	/* r25[6:5]:min */
+		} else if (bw == 6) {
 			if_khz = 3570;
 			filt_cal_lo = 56000;	/* 52000->56000 */
 			filt_gain = 0x10;	/* +3db, 6mhz on */
@@ -1105,6 +1118,32 @@ err:
 	return rc;
 }
 
+int r82xx_set_nomod(struct r82xx_priv *priv)
+{
+	int rc = -1;
+
+	fprintf(stderr, "Using R820T no-mod direct sampling mode\n");
+
+	rc = r82xx_set_tv_standard(priv, 8, TUNER_DIGITAL_TV, 0);
+	if (rc < 0)
+		goto err;
+
+	/* experimentally determined magic numbers
+	 * needs more experimenting with all the registers */
+	rc = r82xx_set_mux(priv, 300000000);
+	if (rc < 0)
+		goto err;
+
+	r82xx_set_pll(priv, 25000000);
+
+err:
+	if (rc < 0)
+		fprintf(stderr, "%s: failed=%d\n", __FUNCTION__, rc);
+	return rc;
+}
+
+
+
 /*
  * r82xx standby logic
  */