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

Add frontend_detach callback in order to allow custom detach. It is
needed when demod 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

@@ -214,6 +214,7 @@ struct dvb_usb_adapter_properties {
  * @read_config: called to resolve device configuration
  * @read_mac_address: called to resolve adapter mac-address
  * @frontend_attach: called to attach the possible frontends
+ * @frontend_detach: called to detach the possible frontends
  * @tuner_attach: called to attach the possible tuners
  * @frontend_ctrl: called to power on/off active frontend
  * @streaming_ctrl: called to start/stop the usb streaming of adapter
@@ -254,6 +255,7 @@ struct dvb_usb_device_properties {
 	int (*read_config) (struct dvb_usb_device *d);
 	int (*read_mac_address) (struct dvb_usb_adapter *, u8 []);
 	int (*frontend_attach) (struct dvb_usb_adapter *);
+	int (*frontend_detach)(struct dvb_usb_adapter *);
 	int (*tuner_attach) (struct dvb_usb_adapter *);
 	int (*frontend_ctrl) (struct dvb_frontend *, int);
 	int (*streaming_ctrl) (struct dvb_frontend *, int);

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

@@ -664,9 +664,10 @@ static int dvb_usbv2_adapter_frontend_init(struct dvb_usb_adapter *adap)
 
 static int dvb_usbv2_adapter_frontend_exit(struct dvb_usb_adapter *adap)
 {
-	int i;
-	dev_dbg(&adap_to_d(adap)->udev->dev, "%s: adap=%d\n", __func__,
-			adap->id);
+	int ret, i;
+	struct dvb_usb_device *d = adap_to_d(adap);
+
+	dev_dbg(&d->udev->dev, "%s: adap=%d\n", __func__, adap->id);
 
 	for (i = MAX_NO_OF_FE_PER_ADAP - 1; i >= 0; i--) {
 		if (adap->fe[i]) {
@@ -675,6 +676,15 @@ static int dvb_usbv2_adapter_frontend_exit(struct dvb_usb_adapter *adap)
 		}
 	}
 
+	if (d->props->frontend_detach) {
+		ret = d->props->frontend_detach(adap);
+		if (ret < 0) {
+			dev_dbg(&d->udev->dev,
+					"%s: frontend_detach() failed=%d\n",
+					__func__, ret);
+		}
+	}
+
 	return 0;
 }