[media] exynos4-is: Add support for asynchronous subdevices registration

Add support for registering external sensor subdevs using
v4l2-async API. The async API is used only for sensor subdevs
and only for booting from DT.

Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Acked-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>
diff --git a/drivers/media/platform/exynos4-is/media-dev.h b/drivers/media/platform/exynos4-is/media-dev.h
index a88cee5..ee1e251 100644
--- a/drivers/media/platform/exynos4-is/media-dev.h
+++ b/drivers/media/platform/exynos4-is/media-dev.h
@@ -32,8 +32,9 @@
 
 #define PINCTRL_STATE_IDLE	"idle"
 
-#define FIMC_MAX_SENSORS	8
+#define FIMC_MAX_SENSORS	4
 #define FIMC_MAX_CAMCLKS	2
+#define DEFAULT_SENSOR_CLK_FREQ	24000000U
 
 /* LCD/ISP Writeback clocks (PIXELASYNCMx) */
 enum {
@@ -79,6 +80,7 @@
 /**
  * struct fimc_sensor_info - image data source subdev information
  * @pdata: sensor's atrributes passed as media device's platform data
+ * @asd: asynchronous subdev registration data structure
  * @subdev: image sensor v4l2 subdev
  * @host: fimc device the sensor is currently linked to
  *
@@ -86,6 +88,7 @@
  */
 struct fimc_sensor_info {
 	struct fimc_source_info pdata;
+	struct v4l2_async_subdev asd;
 	struct v4l2_subdev *subdev;
 	struct fimc_dev *host;
 };
@@ -145,6 +148,9 @@
 		int num_clocks;
 	} clk_provider;
 
+	struct v4l2_async_notifier subdev_notifier;
+	struct v4l2_async_subdev *async_subdevs[FIMC_MAX_SENSORS];
+
 	bool user_subdev_api;
 	spinlock_t slock;
 	struct list_head pipelines;
@@ -162,6 +168,11 @@
 		container_of(me->parent, struct fimc_md, media_dev);
 }
 
+static inline struct fimc_md *notifier_to_fimc_md(struct v4l2_async_notifier *n)
+{
+	return container_of(n, struct fimc_md, subdev_notifier);
+}
+
 static inline void fimc_md_graph_lock(struct exynos_video_entity *ve)
 {
 	mutex_lock(&ve->vdev.entity.parent->graph_mutex);