[media] soc-camera: add host clock callbacks to start and stop the master clock

Currently soc-camera uses a single camera host callback to activate the
interface master clock and to configure the interface for a specific
client. However, during probing we might not have the information about
a client, we just need to activate the clock. Add new camera host driver
callbacks to only start and stop the clock without and client-specific
configuration.
Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/platform/soc_camera/soc_camera.c

@@ -512,10 +512,23 @@ static int soc_camera_add_device(struct soc_camera_device *icd)
 	if (ici->icd)
 		return -EBUSY;
 
+	if (ici->ops->clock_start) {
+		ret = ici->ops->clock_start(ici);
+		if (ret < 0)
+			return ret;
+	}
+
 	ret = ici->ops->add(icd);
-	if (!ret)
+	if (ret < 0)
+		goto eadd;
+
 	ici->icd = icd;
 
+	return 0;
+
+eadd:
+	if (ici->ops->clock_stop)
+		ici->ops->clock_stop(ici);
 	return ret;
 }
 
@@ -527,6 +540,8 @@ static void soc_camera_remove_device(struct soc_camera_device *icd)
 		return;
 
 	ici->ops->remove(icd);
+	if (ici->ops->clock_stop)
+		ici->ops->clock_stop(ici);
 	ici->icd = NULL;
 }
 

include/media/soc_camera.h

@@ -74,6 +74,8 @@ struct soc_camera_host_ops {
 	struct module *owner;
 	int (*add)(struct soc_camera_device *);
 	void (*remove)(struct soc_camera_device *);
+	int (*clock_start)(struct soc_camera_host *);
+	void (*clock_stop)(struct soc_camera_host *);
 	/*
 	 * .get_formats() is called for each client device format, but
 	 * .put_formats() is only called once. Further, if any of the calls to