[media] fc0012 ver. 0.6: introduction of get_rf_strength function

Changes compared to version 0.5 of driver (sent 6 May):
- Initial implementation of get_rf_strength function.
Signed-off-by: Hans-Frieder Vogt <hfvogt@gmx.net>
Signed-off-by: Antti Palosaari <crope@iki.fi>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/common/tuners/fc0012.c

@@ -343,6 +343,74 @@ static int fc0012_get_bandwidth(struct dvb_frontend *fe, u32 *bandwidth)
 	return 0;
 }
 
+#define INPUT_ADC_LEVEL	-8
+
+static int fc0012_get_rf_strength(struct dvb_frontend *fe, u16 *strength)
+{
+	struct fc0012_priv *priv = fe->tuner_priv;
+	int ret;
+	unsigned char tmp;
+	int int_temp, lna_gain, int_lna, tot_agc_gain, power;
+	const int fc0012_lna_gain_table[] = {
+		/* low gain */
+		-63, -58, -99, -73,
+		-63, -65, -54, -60,
+		/* middle gain */
+		 71,  70,  68,  67,
+		 65,  63,  61,  58,
+		/* high gain */
+		197, 191, 188, 186,
+		184, 182, 181, 179,
+	};
+
+	if (fe->ops.i2c_gate_ctrl)
+		fe->ops.i2c_gate_ctrl(fe, 1); /* open I2C-gate */
+
+	ret = fc0012_writereg(priv, 0x12, 0x00);
+	if (ret)
+		goto err;
+
+	ret = fc0012_readreg(priv, 0x12, &tmp);
+	if (ret)
+		goto err;
+	int_temp = tmp;
+
+	ret = fc0012_readreg(priv, 0x13, &tmp);
+	if (ret)
+		goto err;
+	lna_gain = tmp & 0x1f;
+
+	if (fe->ops.i2c_gate_ctrl)
+		fe->ops.i2c_gate_ctrl(fe, 0); /* close I2C-gate */
+
+	if (lna_gain < ARRAY_SIZE(fc0012_lna_gain_table)) {
+		int_lna = fc0012_lna_gain_table[lna_gain];
+		tot_agc_gain = (abs((int_temp >> 5) - 7) - 2 +
+				(int_temp & 0x1f)) * 2;
+		power = INPUT_ADC_LEVEL - tot_agc_gain - int_lna / 10;
+
+		if (power >= 45)
+			*strength = 255;	/* 100% */
+		else if (power < -95)
+			*strength = 0;
+		else
+			*strength = (power + 95) * 255 / 140;
+
+		*strength |= *strength << 8;
+	} else {
+		ret = -1;
+	}
+
+	goto exit;
+
+err:
+	if (fe->ops.i2c_gate_ctrl)
+		fe->ops.i2c_gate_ctrl(fe, 0); /* close I2C-gate */
+exit:
+	if (ret)
+		warn("%s: failed: %d", __func__, ret);
+	return ret;
+}
 
 static const struct dvb_tuner_ops fc0012_tuner_ops = {
 	.info = {
@@ -363,6 +431,8 @@ static const struct dvb_tuner_ops fc0012_tuner_ops = {
 	.get_frequency	= fc0012_get_frequency,
 	.get_if_frequency = fc0012_get_if_frequency,
 	.get_bandwidth	= fc0012_get_bandwidth,
+
+	.get_rf_strength = fc0012_get_rf_strength,
 };
 
 struct dvb_frontend *fc0012_attach(struct dvb_frontend *fe,
@@ -394,4 +464,4 @@ EXPORT_SYMBOL(fc0012_attach);
 MODULE_DESCRIPTION("Fitipower FC0012 silicon tuner driver");
 MODULE_AUTHOR("Hans-Frieder Vogt <hfvogt@gmx.net>");
 MODULE_LICENSE("GPL");
-MODULE_VERSION("0.5");
+MODULE_VERSION("0.6");