---

yaml
---
r: 367121
b: refs/heads/master
c: 50786dd
h: refs/heads/master
i:
  367119: f80d920
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: f8fde0e045aeac4417b09bef01b3ada74a4cbc80
+refs/heads/master: 50786ddfa8efef696ec4f72460874f3b46dc2401

trunk/drivers/media/tuners/r820t.c

@@ -320,6 +320,20 @@ static int r820t_xtal_capacitor[][2] = {
 	{ 0x10, XTAL_HIGH_CAP_0P },
 };
 
+/*
+ * measured with a Racal 6103E GSM test set at 928 MHz with -60 dBm
+ * input power, for raw results see:
+ *	http://steve-m.de/projects/rtl-sdr/gain_measurement/r820t/
+ */
+
+static const int r820t_lna_gain_steps[]  = {
+	0, 9, 13, 40, 38, 13, 31, 22, 26, 31, 26, 14, 19, 5, 35, 13
+};
+
+static const int r820t_mixer_gain_steps[]  = {
+	0, 5, 10, 10, 19, 9, 10, 25, 17, 10, 8, 16, 13, 6, 3, -8
+};
+
 /*
  * I2C read/write code and shadow registers logic
  */
@@ -1094,6 +1108,78 @@ static int r820t_read_gain(struct r820t_priv *priv)
 	return ((data[3] & 0x0f) << 1) + ((data[3] & 0xf0) >> 4);
 }
 
+static int r820t_set_gain_mode(struct r820t_priv *priv,
+			       bool set_manual_gain,
+			       int gain)
+{
+	int rc;
+
+	if (set_manual_gain) {
+		int i, total_gain = 0;
+		uint8_t mix_index = 0, lna_index = 0;
+		u8 data[4];
+
+		/* LNA auto off */
+		rc = r820t_write_reg_mask(priv, 0x05, 0x10, 0x10);
+		if (rc < 0)
+			return rc;
+
+		 /* Mixer auto off */
+		rc = r820t_write_reg_mask(priv, 0x07, 0, 0x10);
+		if (rc < 0)
+			return rc;
+
+		rc = r820_read(priv, 0x00, data, sizeof(data));
+		if (rc < 0)
+			return rc;
+
+		/* set fixed VGA gain for now (16.3 dB) */
+		rc = r820t_write_reg_mask(priv, 0x0c, 0x08, 0x9f);
+		if (rc < 0)
+			return rc;
+
+		for (i = 0; i < 15; i++) {
+			if (total_gain >= gain)
+				break;
+
+			total_gain += r820t_lna_gain_steps[++lna_index];
+
+			if (total_gain >= gain)
+				break;
+
+			total_gain += r820t_mixer_gain_steps[++mix_index];
+		}
+
+		/* set LNA gain */
+		rc = r820t_write_reg_mask(priv, 0x05, lna_index, 0x0f);
+		if (rc < 0)
+			return rc;
+
+		/* set Mixer gain */
+		rc = r820t_write_reg_mask(priv, 0x07, mix_index, 0x0f);
+		if (rc < 0)
+			return rc;
+	} else {
+		/* LNA */
+		rc = r820t_write_reg_mask(priv, 0x05, 0, 0xef);
+		if (rc < 0)
+			return rc;
+
+		/* Mixer */
+		rc = r820t_write_reg_mask(priv, 0x07, 0x10, 0xef);
+		if (rc < 0)
+			return rc;
+
+		/* set fixed VGA gain for now (26.5 dB) */
+		rc = r820t_write_reg_mask(priv, 0x0c, 0x0b, 0x9f);
+		if (rc < 0)
+			return rc;
+	}
+
+	return 0;
+}
+
+
 static int generic_set_freq(struct dvb_frontend *fe,
 			    u32 freq /* in HZ */,
 			    unsigned bw,
@@ -1121,6 +1207,11 @@ static int generic_set_freq(struct dvb_frontend *fe,
 	rc = r820t_set_mux(priv, lo_freq);
 	if (rc < 0)
 		goto err;
+
+	rc = r820t_set_gain_mode(priv, true, 0);
+	if (rc < 0)
+		goto err;
+
 	rc = r820t_set_pll(priv, lo_freq);
 	if (rc < 0 || !priv->has_lock)
 		goto err;