V4L/DVB (9883): gspca - ov534: Show sensor ID.

The original version of sccb_read_reg() is from Jim Paris.

NOTE: as it is now reading sensor ID won't work for sensors on different
i2c slave address.
Signed-off-by: Antonio Ospite <ospite@studenti.unina.it>
Signed-off-by: Jean-Francois Moine <moinejf@free.fr>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/video/gspca/ov534.c

@@ -149,6 +149,20 @@ static void sccb_reg_write(struct usb_device *udev, u16 reg, u8 val)
 		PDEBUG(D_ERR, "sccb_reg_write failed");
 }
 
+static u8 sccb_reg_read(struct usb_device *udev, u16 reg)
+{
+	ov534_reg_write(udev, OV534_REG_SUBADDR, reg);
+	ov534_reg_write(udev, OV534_REG_OPERATION, OV534_OP_WRITE_2);
+	if (!sccb_check_status(udev))
+		PDEBUG(D_ERR, "sccb_reg_read failed 1");
+
+	ov534_reg_write(udev, OV534_REG_OPERATION, OV534_OP_READ_2);
+	if (!sccb_check_status(udev))
+		PDEBUG(D_ERR, "sccb_reg_read failed 2");
+
+	return ov534_reg_read(udev, OV534_REG_READ);
+}
+
 static const __u8 ov534_reg_initdata[][2] = {
 	{ 0xe7, 0x3a },
 
@@ -339,6 +353,9 @@ static void ov534_setup(struct usb_device *udev)
 		ov534_reg_write(udev, ov534_reg_initdata[i][0],
 				ov534_reg_initdata[i][1]);
 
+	PDEBUG(D_PROBE, "sensor is ov%02x%02x",
+		sccb_reg_read(udev, 0x0a), sccb_reg_read(udev, 0x0b));
+
 	ov534_set_led(udev, 1);
 
 	/* Initialize sensor */