staging/vc04_services/bcm2835-camera: distinct numeration and names for devices

Create a static atomic counter for numerating cameras.
Use the Media Subsystem Kernel Internal API to create distinct
device-names, so that the camera-number (given by the counter)
matches the camera-name.

Co-developed-by: Kay Friedrich <kay.friedrich@fau.de>
Signed-off-by: Kay Friedrich <kay.friedrich@fau.de>
Signed-off-by: Michael Kupfer <michael.kupfer@fau.de>
Link: https://lore.kernel.org/r/20191206085432.19962-1-michael.kupfer@fau.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/vc04_services/bcm2835-camera/bcm2835-camera.c b/drivers/staging/vc04_services/bcm2835-camera/bcm2835-camera.c
index beb6a00..1ef31a9 100644 (file)
--- a/drivers/staging/vc04_services/bcm2835-camera/bcm2835-camera.c
+++ b/drivers/staging/vc04_services/bcm2835-camera/bcm2835-camera.c
@@ -60,6 +60,9 @@ MODULE_PARM_DESC(max_video_width, "Threshold for video mode");
 module_param(max_video_height, int, 0644);
 MODULE_PARM_DESC(max_video_height, "Threshold for video mode");
 
+/* camera instance counter */
+static atomic_t camera_instance = ATOMIC_INIT(0);
+
 /* global device data array */
 static struct bm2835_mmal_dev *gdev[MAX_BCM2835_CAMERAS];
 
@@ -1870,7 +1873,6 @@ static int bcm2835_mmal_probe(struct platform_device *pdev)
 
                /* v4l2 core mutex used to protect all fops and v4l2 ioctls. */
                mutex_init(&dev->mutex);
-               dev->camera_num = camera;
                dev->max_width = resolutions[camera][0];
                dev->max_height = resolutions[camera][1];
 
@@ -1886,8 +1888,9 @@ static int bcm2835_mmal_probe(struct platform_device *pdev)
                dev->capture.fmt = &formats[3]; /* JPEG */
 
                /* v4l device registration */
-               snprintf(dev->v4l2_dev.name, sizeof(dev->v4l2_dev.name),
-                        "%s", BM2835_MMAL_MODULE_NAME);
+               dev->camera_num = v4l2_device_set_name(&dev->v4l2_dev,
+                                                      BM2835_MMAL_MODULE_NAME,
+                                                      &camera_instance);
                ret = v4l2_device_register(NULL, &dev->v4l2_dev);
                if (ret) {
                        dev_err(&pdev->dev, "%s: could not register V4L2 device: %d\n",