media: adv7180: Default to the first valid input

The hardware default is differential CVBS on AIN1 & 2, which
isn't very useful.

Select the first input that is defined as valid for the
chip variant (typically CVBS_AIN1).

Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.org>

drivers/media/i2c/adv7180.c

@@ -1336,6 +1336,7 @@ static const struct adv7180_chip_info adv7282_m_info = {
 static int init_device(struct adv7180_state *state)
 {
 	int ret;
+	int i;
 
 	mutex_lock(&state->mutex);
 
@@ -1383,6 +1384,18 @@ static int init_device(struct adv7180_state *state)
 			goto out_unlock;
 	}
 
+	/* Select first valid input */
+	for (i = 0; i < 32; i++) {
+		if (BIT(i) & state->chip_info->valid_input_mask) {
+			ret = state->chip_info->select_input(state, i);
+
+			if (ret == 0) {
+				state->input = i;
+				break;
+			}
+		}
+	}
+
 out_unlock:
 	mutex_unlock(&state->mutex);