greybus: camera-gb: Add description of interface header

Add description for all interface structures in
gb-camera.h.
Signed-off-by: Evgeniy Borisov <eborisov@mm-sol.com>
Reviewed-by: Gjorgji Rosikopulos <grosikopulos@mm-sol.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>

drivers/staging/greybus/gb-camera.h

@@ -15,6 +15,19 @@
 /* Output flags returned */
 #define GB_CAMERA_OUT_FLAG_ADJUSTED	(1 << 0)
 
+/**
+ * struct gb_camera_stream - Represents greybus camera stream.
+ * @width: Stream width in pixels.
+ * @height: Stream height in pixels.
+ * @pixel_code: Media bus pixel code.
+ * @vc: MIPI CSI virtual channel.
+ * @dt: MIPI CSI data types. Most formats use a single data type, in which case
+ *      the second element will be ignored.
+ * @max_size: Maximum size of a frame in bytes. The camera module guarantees
+ *            that all data between the Frame Start and Frame End packet for
+ *            the associated virtual channel and data type(s) will not exceed
+ *            this size.
+ */
 struct gb_camera_stream {
 	unsigned int width;
 	unsigned int height;
@@ -28,7 +41,7 @@ struct gb_camera_stream {
  * struct gb_camera_csi_params - CSI configuration parameters
  * @num_lanes: number of CSI data lanes
  * @clk_freq: CSI clock frequency in Hz
- * @lines_per_second:	total number of lines in a second of transmission
+ * @lines_per_second: Total number of lines in a second of transmission
  *                    (blanking included)
  */
 struct gb_camera_csi_params {
@@ -37,6 +50,46 @@ struct gb_camera_csi_params {
 	unsigned int lines_per_second;
 };
 
+/**
+ * struct gb_camera_ops - Greybus camera operations, used by the Greybus camera
+ *                        driver to expose operations to the host camera driver.
+ * @capabilities: Retrieve camera capabilities and store them in the buffer
+ *                'buf' capabilities. The buffer maximum size is specified by
+ *                the caller in the 'size' parameter, and the effective
+ *                capabilities size is returned from the function. If the buffer
+ *                size is too small to hold the capabilities an error is
+ *                returned and the buffer is left untouched.
+ *
+ * @configure_streams: Negotiate configuration and prepare the module for video
+ *                     capture. The caller specifies the number of streams it
+ *                     requests in the 'nstreams' argument and the associated
+ *                     streams configurations in the 'streams' argument. The
+ *                     GB_CAMERA_IN_FLAG_TEST 'flag' can be set to test a
+ *                     configuration without applying it, otherwise the
+ *                     configuration is applied by the module. The module can
+ *                     decide to modify the requested configuration, including
+ *                     using a different number of streams. In that case the
+ *                     modified configuration won't be applied, the
+ *                     GB_CAMERA_OUT_FLAG_ADJUSTED 'flag' will be set upon
+ *                     return, and the modified configuration and number of
+ *                     streams stored in 'streams' and 'array'. The module
+ *                     returns its CSI-2 bus parameters in the 'csi_params'
+ *                     structure in all cases.
+ *
+ * @capture: Submit a capture request. The supplied 'request_id' must be unique
+ *           and higher than the IDs of all the previously submitted requests.
+ *           The 'streams' argument specifies which streams are affected by the
+ *           request in the form of a bitmask, with bits corresponding to the
+ *           configured streams indexes. If the request contains settings, the
+ *           'settings' argument points to the settings buffer and its size is
+ *           specified by the 'settings_size' argument. Otherwise the 'settings'
+ *           argument should be set to NULL and 'settings_size' to 0.
+ *
+ * @flush: Flush the capture requests queue. Return the ID of the last request
+ *         that will processed by the device before it stops transmitting video
+ *         frames. All queued capture requests with IDs higher than the returned
+ *         ID will be dropped without being processed.
+ */
 struct gb_camera_ops {
 	ssize_t (*capabilities)(void *priv, char *buf, size_t len);
 	int (*configure_streams)(void *priv, unsigned int *nstreams,
@@ -48,6 +101,12 @@ struct gb_camera_ops {
 	int (*flush)(void *priv, u32 *request_id);
 };
 
+/**
+ * struct gb_camera_module - Represents greybus camera module.
+ * @priv: Module private data, passed to all camera operations.
+ * @ops: Greybus camera operation callbacks.
+ * @list: List entry in the camera modules list.
+ */
 struct gb_camera_module {
 	void *priv;
 	const struct gb_camera_ops *ops;