[media] dvb_usb_v2: implement .read_config()

That callback is called	only once when device is connected.
Call is done after the possible firmware is downloaded to the device,
just after the .power_ctrl() and before adapters are created.
Signed-off-by: Antti Palosaari <crope@iki.fi>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

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

@@ -275,6 +275,7 @@ struct dvb_usb_device_properties {
 	struct dvb_usb_adapter_properties adapter[MAX_NO_OF_ADAPTER_PER_DEVICE];
 
 	int (*power_ctrl)       (struct dvb_usb_device *, int);
+	int (*read_config) (struct dvb_usb_device *d);
 	int (*read_mac_address) (struct dvb_usb_device *, u8 []);
 
 #define WARM                  0

drivers/media/dvb/dvb-usb/dvb_usb_init.c

@@ -190,6 +190,13 @@ static int dvb_usb_init(struct dvb_usb_device *d)
 	/* check the capabilities and set appropriate variables */
 	dvb_usb_device_power_ctrl(d, 1);
 
+	/* read config */
+	if (d->props.read_config) {
+		ret = d->props.read_config(d);
+		if (ret < 0)
+			goto err;
+	}
+
 	ret = dvb_usb_i2c_init(d);
 	if (ret == 0)
 		ret = dvb_usb_adapter_init(d);
@@ -209,6 +216,9 @@ static int dvb_usb_init(struct dvb_usb_device *d)
 	dvb_usb_device_power_ctrl(d, 0);
 
 	return 0;
+err:
+	pr_debug("%s: failed=%d\n", __func__, ret);
+	return ret;
 }
 
 int dvb_usb_device_power_ctrl(struct dvb_usb_device *d, int onoff)