staging: bcm2835: Don't probe if no camera is detected

It is a waste of resources to load the camera driver in case there isn't
a camera actually connected to the Raspberry Pi. This solution also
avoids a NULL ptr dereference of mmal instance on driver unload.

Fixes: 7b3ad5abf027 ("staging: Import the BCM2835 MMAL-based V4L2 camera driver.")
Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>

diff --git a/drivers/staging/vc04_services/bcm2835-camera/bcm2835-camera.c b/drivers/staging/vc04_services/bcm2835-camera/bcm2835-camera.c
index 0e62648..84ca22d 100644 (file)
--- a/drivers/staging/vc04_services/bcm2835-camera/bcm2835-camera.c
+++ b/drivers/staging/vc04_services/bcm2835-camera/bcm2835-camera.c
@@ -1847,6 +1847,12 @@ static int bcm2835_mmal_probe(struct platform_device *pdev)
        num_cameras = get_num_cameras(instance,
                                      resolutions,
                                      MAX_BCM2835_CAMERAS);
+
+       if (num_cameras < 1) {
+               ret = -ENODEV;
+               goto cleanup_mmal;
+       }
+
        if (num_cameras > MAX_BCM2835_CAMERAS)
                num_cameras = MAX_BCM2835_CAMERAS;
 
@@ -1955,6 +1961,9 @@ cleanup_gdev:
                gdev[i] = NULL;
        }
 
+cleanup_mmal:
+       vchiq_mmal_finalise(instance);
+
        return ret;
 }