[PATCH/RFC] V4L: add media bus configuration subdev operations

[Guennadi Liakhovetski <g.liakhovetski@gmx.de>]

Add media bus configuration types and two subdev operations to get 
supported mediabus configurations and to set a specific configuration. 
Subdevs can support several configurations, e.g., they can send video data 
on 1 or several lanes, can be configured to use a specific CSI-2 channel, 
in such cases subdevice drivers return bitmasks with all respective bits 
set. When a set-configuration operation is called, it has to specify a 
non-ambiguous configuration.

Signed-off-by: Stanimir Varbanov <svarbanov@mm-sol.com>
Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
---

This change would allow a re-use of soc-camera and "standard" subdev 
drivers. It is a modified and extended version of

http://article.gmane.org/gmane.linux.drivers.video-input-infrastructure/29408

therefore the original Sob. After this we only would have to switch to the 
control framework:) Please, comment.

diff --git a/include/media/v4l2-mediabus.h b/include/media/v4l2-mediabus.h
index 971c7fa..0983b7b 100644
--- a/include/media/v4l2-mediabus.h
+++ b/include/media/v4l2-mediabus.h
@@ -13,6 +13,76 @@
 
 #include <linux/v4l2-mediabus.h>
 
+/* Parallel flags */
+/* Can the client run in master or in slave mode */
+#define V4L2_MBUS_MASTER			(1 << 0)
+#define V4L2_MBUS_SLAVE				(1 << 1)
+/* Which signal polarities it supports */
+#define V4L2_MBUS_HSYNC_ACTIVE_HIGH		(1 << 2)
+#define V4L2_MBUS_HSYNC_ACTIVE_LOW		(1 << 3)
+#define V4L2_MBUS_VSYNC_ACTIVE_HIGH		(1 << 4)
+#define V4L2_MBUS_VSYNC_ACTIVE_LOW		(1 << 5)
+#define V4L2_MBUS_PCLK_SAMPLE_RISING		(1 << 6)
+#define V4L2_MBUS_PCLK_SAMPLE_FALLING		(1 << 7)
+#define V4L2_MBUS_DATA_ACTIVE_HIGH		(1 << 8)
+#define V4L2_MBUS_DATA_ACTIVE_LOW		(1 << 9)
+/* Which datawidths are supported */
+#define V4L2_MBUS_DATAWIDTH_4			(1 << 10)
+#define V4L2_MBUS_DATAWIDTH_8			(1 << 11)
+#define V4L2_MBUS_DATAWIDTH_9			(1 << 12)
+#define V4L2_MBUS_DATAWIDTH_10			(1 << 13)
+#define V4L2_MBUS_DATAWIDTH_15			(1 << 14)
+#define V4L2_MBUS_DATAWIDTH_16			(1 << 15)
+
+#define V4L2_MBUS_DATAWIDTH_MASK	(V4L2_MBUS_DATAWIDTH_4 | V4L2_MBUS_DATAWIDTH_8 | \
+					 V4L2_MBUS_DATAWIDTH_9 | V4L2_MBUS_DATAWIDTH_10 | \
+					 V4L2_MBUS_DATAWIDTH_15 | V4L2_MBUS_DATAWIDTH_16)
+
+/* Serial flags */
+/* How many lanes the client can use */
+#define V4L2_MBUS_CSI2_1_LANE			(1 << 0)
+#define V4L2_MBUS_CSI2_2_LANE			(1 << 1)
+#define V4L2_MBUS_CSI2_3_LANE			(1 << 2)
+#define V4L2_MBUS_CSI2_4_LANE			(1 << 3)
+/* On which channels it can send video data */
+#define V4L2_MBUS_CSI2_CHANNEL_0			(1 << 4)
+#define V4L2_MBUS_CSI2_CHANNEL_1			(1 << 5)
+#define V4L2_MBUS_CSI2_CHANNEL_2			(1 << 6)
+#define V4L2_MBUS_CSI2_CHANNEL_3			(1 << 7)
+/* Does it support only continuous or also non-contimuous clock mode */
+#define V4L2_MBUS_CSI2_CONTINUOUS_CLOCK		(1 << 8)
+#define V4L2_MBUS_CSI2_NONCONTINUOUS_CLOCK	(1 << 9)
+
+#define V4L2_MBUS_CSI2_LANES		(V4L2_MBUS_CSI2_1_LANE | V4L2_MBUS_CSI2_2_LANE | \
+					 V4L2_MBUS_CSI2_3_LANE | V4L2_MBUS_CSI2_4_LANE)
+#define V4L2_MBUS_CSI2_CHANNELS		(V4L2_MBUS_CSI2_CHANNEL_0 | V4L2_MBUS_CSI2_CHANNEL_1 | \
+					 V4L2_MBUS_CSI2_CHANNEL_2 | V4L2_MBUS_CSI2_CHANNEL_3)
+
+/**
+ * v4l2_mbus_type - media bus type
+ * @V4L2_MBUS_PARALLEL:	parallel interface with hsync and vsync
+ * @V4L2_MBUS_BT656:	parallel interface with embedded synchronisation
+ * @V4L2_MBUS_CSI2:	MIPI CSI-2 serial interface
+ */
+enum v4l2_mbus_type {
+	V4L2_MBUS_PARALLEL,
+	V4L2_MBUS_BT656,
+	V4L2_MBUS_CSI2,
+};
+
+/**
+ * v4l2_mbus_config - media bus configuration
+ * @type:	interface type
+ * @flags:	configuration flags, depending on @type
+ * @clk:	output clock, the bridge driver can try to use clk_set_parent()
+ *		to specify the master clock to the client
+ */
+struct v4l2_mbus_config {
+	enum v4l2_mbus_type type;
+	unsigned long flags;
+	struct clk *clk;
+};
+
 static inline void v4l2_fill_pix_format(struct v4l2_pix_format *pix_fmt,
 				const struct v4l2_mbus_framefmt *mbus_fmt)
 {
diff --git a/include/media/v4l2-subdev.h b/include/media/v4l2-subdev.h
index 1562c4f..6ea25f4 100644
--- a/include/media/v4l2-subdev.h
+++ b/include/media/v4l2-subdev.h
@@ -255,6 +255,10 @@ struct v4l2_subdev_audio_ops {
    try_mbus_fmt: try to set a pixel format on a video data source
 
    s_mbus_fmt: set a pixel format on a video data source
+
+   g_mbus_param: get supported mediabus configurations
+
+   s_mbus_param: set a certain mediabus configuration
  */
 struct v4l2_subdev_video_ops {
 	int (*s_routing)(struct v4l2_subdev *sd, u32 input, u32 output, u32 config);
@@ -294,6 +298,8 @@ struct v4l2_subdev_video_ops {
 			    struct v4l2_mbus_framefmt *fmt);
 	int (*s_mbus_fmt)(struct v4l2_subdev *sd,
 			  struct v4l2_mbus_framefmt *fmt);
+	int (*g_mbus_param)(struct v4l2_subdev *sd, struct v4l2_mbus_config *cfg);
+	int (*s_mbus_param)(struct v4l2_subdev *sd, struct v4l2_mbus_config *cfg);
 };
 
 /*