[media] dvb-usb-v2: add tuner_detach callback

Add tuner_detach callback in order to allow custom detach. It is
needed when tuner driver is implemented I2C client or some other
kernel bus, but not proprietary dvb_attach / dvb_detach.
Signed-off-by: Antti Palosaari <crope@iki.fi>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>

drivers/media/usb/dvb-usb-v2/dvb_usb.h

@@ -257,6 +257,7 @@ struct dvb_usb_device_properties {
 	int (*frontend_attach) (struct dvb_usb_adapter *);
 	int (*frontend_detach)(struct dvb_usb_adapter *);
 	int (*tuner_attach) (struct dvb_usb_adapter *);
+	int (*tuner_detach)(struct dvb_usb_adapter *);
 	int (*frontend_ctrl) (struct dvb_frontend *, int);
 	int (*streaming_ctrl) (struct dvb_frontend *, int);
 	int (*init) (struct dvb_usb_device *);

drivers/media/usb/dvb-usb-v2/dvb_usb_core.c

@@ -676,6 +676,14 @@ static int dvb_usbv2_adapter_frontend_exit(struct dvb_usb_adapter *adap)
 		}
 	}
 
+	if (d->props->tuner_detach) {
+		ret = d->props->tuner_detach(adap);
+		if (ret < 0) {
+			dev_dbg(&d->udev->dev, "%s: tuner_detach() failed=%d\n",
+					__func__, ret);
+		}
+	}
+
 	if (d->props->frontend_detach) {
 		ret = d->props->frontend_detach(adap);
 		if (ret < 0) {