[media] mt2060: implement sleep

I saw from ZyDAS ZD1301 sniffs it sets chip sleeping by using
REG_MISC_CTRL. That has very huge effect for power management, around
0.9W. Sleep is still disabled for all the old hardware just to avoid
possible regression as meaning of register bits are unknown.

I tested it also with some other devices and it seems to be working,
but I still consider it to be too risky to change it default.
Signed-off-by: Antti Palosaari <crope@iki.fi>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

drivers/media/tuners/mt2060.c

@@ -313,9 +313,16 @@ static int mt2060_init(struct dvb_frontend *fe)
 	if (fe->ops.i2c_gate_ctrl)
 		fe->ops.i2c_gate_ctrl(fe, 1); /* open i2c_gate */
 
+	if (priv->sleep) {
+		ret = mt2060_writereg(priv, REG_MISC_CTRL, 0x20);
+		if (ret)
+			goto err_i2c_gate_ctrl;
+	}
+
 	ret = mt2060_writereg(priv, REG_VGAG,
 			      (priv->cfg->clock_out << 6) | 0x33);
 
+err_i2c_gate_ctrl:
 	if (fe->ops.i2c_gate_ctrl)
 		fe->ops.i2c_gate_ctrl(fe, 0); /* close i2c_gate */
 
@@ -332,7 +339,13 @@ static int mt2060_sleep(struct dvb_frontend *fe)
 
 	ret = mt2060_writereg(priv, REG_VGAG,
 			      (priv->cfg->clock_out << 6) | 0x30);
+	if (ret)
+		goto err_i2c_gate_ctrl;
+
+	if (priv->sleep)
+		ret = mt2060_writereg(priv, REG_MISC_CTRL, 0xe8);
 
+err_i2c_gate_ctrl:
 	if (fe->ops.i2c_gate_ctrl)
 		fe->ops.i2c_gate_ctrl(fe, 0); /* close i2c_gate */
 
@@ -435,6 +448,7 @@ static int mt2060_probe(struct i2c_client *client,
 	dev->if1_freq = pdata->if1 ? pdata->if1 : 1220;
 	dev->client = client;
 	dev->i2c_max_regs = pdata->i2c_write_max ? pdata->i2c_write_max - 1 : ~0;
+	dev->sleep = true;
 
 	ret = mt2060_readreg(dev, REG_PART_REV, &chip_id);
 	if (ret) {
@@ -449,14 +463,21 @@ static int mt2060_probe(struct i2c_client *client,
 		goto err;
 	}
 
+	/* Power on, calibrate, sleep */
+	ret = mt2060_writereg(dev, REG_MISC_CTRL, 0x20);
+	if (ret)
+		goto err;
+	mt2060_calibrate(dev);
+	ret = mt2060_writereg(dev, REG_MISC_CTRL, 0xe8);
+	if (ret)
+		goto err;
+
 	dev_info(&client->dev, "Microtune MT2060 successfully identified\n");
 	memcpy(&fe->ops.tuner_ops, &mt2060_tuner_ops, sizeof(fe->ops.tuner_ops));
 	fe->ops.tuner_ops.release = NULL;
 	fe->tuner_priv = dev;
 	i2c_set_clientdata(client, dev);
 
-	mt2060_calibrate(dev);
-
 	return 0;
 err:
 	dev_dbg(&client->dev, "failed=%d\n", ret);

drivers/media/tuners/mt2060_priv.h

@@ -98,6 +98,14 @@ struct mt2060_priv {
 	u32 frequency;
 	u16 if1_freq;
 	u8  fmfreq;
+
+	/*
+	 * Use REG_MISC_CTRL register for sleep. That drops sleep power usage
+	 * about 0.9W (huge!). Register bit meanings are unknown, so let it be
+	 * disabled by default to avoid possible regression. Convert driver to
+	 * i2c model in order to enable it.
+	 */
+	bool sleep;
 };
 
 #endif