[PATCH 3/4] media: af9035: add support for Logilink VG0022A

[Mauro Carvalho Chehab <mchehab+samsung@kernel.org>]

This it930x-based device has an issue with si2068.

When the si2168 firmware that came with the device is replaced
by a new one, any I2C data received from the tuner will be
replaced by 0xff.

Probably, the vendor firmware has some patch specifically
designed for this device. So, we can't replace by the generic
firmware.

The right solution would be to extract the si2168 firmware from
the original driver and ask the driver to load the specifically
designed firmware, but, while we don't have that, the next best
solution is to just keep the original firmware at the device.

For more details, see the discussions at:
	https://lore.kernel.org/linux-media/20191002141359.30166-2-gonsolo@gmail.com/

Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
---
 drivers/media/usb/dvb-usb-v2/af9035.c | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/drivers/media/usb/dvb-usb-v2/af9035.c b/drivers/media/usb/dvb-usb-v2/af9035.c
index 3afd18733614..e555483c3077 100644
--- a/drivers/media/usb/dvb-usb-v2/af9035.c
+++ b/drivers/media/usb/dvb-usb-v2/af9035.c
@@ -1255,6 +1255,23 @@ static int it930x_frontend_attach(struct dvb_usb_adapter *adap)
 	si2168_config.fe = &adap->fe[0];
 	si2168_config.ts_mode = SI2168_TS_SERIAL;
 
+	/*
+	 * HACK: The Logilink VG0022A has a bug: when the si2168
+	 * firmware that came with the device is replaced by a new
+	 * one, the I2C transfers to the tuner will return just 0xff.
+	 *
+	 * Probably, the vendor firmware has some patch specifically
+	 * designed for this device. So, we can't replace by the
+	 * generic firmware. The right solution would be to extract
+	 * the si2168 firmware from the original driver and ask the
+	 * driver to load the specifically designed firmware, but,
+	 * while we don't have that, the next best solution is to just
+	 * keep the original firmware at the device.
+	 */
+	if (le16_to_cpu(d->udev->descriptor.idVendor) == USB_VID_DEXATEK &&
+	    le16_to_cpu(d->udev->descriptor.idProduct) == 0x0100)
+		si2168_config.dont_load_firmware = true;
+
 	state->af9033_config[adap->id].fe = &adap->fe[0];
 	state->af9033_config[adap->id].ops = &state->ops;
 	ret = af9035_add_i2c_dev(d, "si2168",
@@ -2121,6 +2138,8 @@ static const struct usb_device_id af9035_id_table[] = {
 		&it930x_props, "ITE 9303 Generic", NULL) },
 	{ DVB_USB_DEVICE(USB_VID_AVERMEDIA, USB_PID_AVERMEDIA_TD310,
 		&it930x_props, "AVerMedia TD310 DVB-T2", NULL) },
+	{ DVB_USB_DEVICE(USB_VID_DEXATEK, 0x0100,
+		&it930x_props, "Logilink VG0022A", NULL) },
 	{ }
 };
 MODULE_DEVICE_TABLE(usb, af9035_id_table);
-- 
2.21.0