staging: media: tegra-video: add H/V flip controls

Tegra20 can do horizontal and vertical image flip, but Tegra210 cannot
(either the hardware, or this driver).

In preparation to adding Tegra20 support, add a flag in struct tegra_vi_soc
so the generic vi.c code knows whether the flip controls should be added or
not.

Also provide a generic implementation that simply sets two flags in the
channel struct. The Tegra20 implementation will enable flipping at stream
start based on those flags.
Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
Reviewed-by: Dmitry Osipenko <digetx@gmail.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>

drivers/staging/media/tegra-video/vi.c

@@ -30,7 +30,7 @@
 #include "vi.h"
 #include "video.h"
 
-#define MAX_CID_CONTROLS		1
+#define MAX_CID_CONTROLS		3
 
 /**
  * struct tegra_vi_graph_entity - Entity in the video graph
@@ -912,6 +912,12 @@ static int vi_s_ctrl(struct v4l2_ctrl *ctrl)
 	case V4L2_CID_TEGRA_SYNCPT_TIMEOUT_RETRY:
 		chan->syncpt_timeout_retry = ctrl->val;
 		break;
+	case V4L2_CID_HFLIP:
+		chan->hflip = ctrl->val;
+		break;
+	case V4L2_CID_VFLIP:
+		chan->vflip = ctrl->val;
+		break;
 	default:
 		return -EINVAL;
 	}
@@ -983,6 +989,12 @@ static int tegra_channel_setup_ctrl_handler(struct tegra_vi_channel *chan)
 		v4l2_ctrl_handler_free(&chan->ctrl_handler);
 		return ret;
 	}
+
+	if (chan->vi->soc->has_h_v_flip) {
+		v4l2_ctrl_new_std(&chan->ctrl_handler, &vi_ctrl_ops, V4L2_CID_HFLIP, 0, 1, 1, 0);
+		v4l2_ctrl_new_std(&chan->ctrl_handler, &vi_ctrl_ops, V4L2_CID_VFLIP, 0, 1, 1, 0);
+	}
+
 #endif
 
 	/* setup the controls */

drivers/staging/media/tegra-video/vi.h

@@ -74,6 +74,7 @@ struct tegra_vi_ops {
  * @hw_revision: VI hw_revision
  * @vi_max_channels: supported max streaming channels
  * @vi_max_clk_hz: VI clock max frequency
+ * @has_h_v_flip: the chip can do H and V flip, and the driver implements it
  */
 struct tegra_vi_soc {
 	const struct tegra_video_format *video_formats;
@@ -83,6 +84,7 @@ struct tegra_vi_soc {
 	u32 hw_revision;
 	unsigned int vi_max_channels;
 	unsigned int vi_max_clk_hz;
+	bool has_h_v_flip:1;
 };
 
 /**
@@ -172,6 +174,9 @@ struct tegra_vi {
  * @tpg_fmts_bitmap: a bitmap for supported TPG formats
  * @pg_mode: test pattern generator mode (disabled/direct/patch)
  * @notifier: V4L2 asynchronous subdevs notifier
+ *
+ * @hflip: Horizontal flip is enabled
+ * @vflip: Vertical flip is enabled
  */
 struct tegra_vi_channel {
 	struct list_head list;
@@ -222,6 +227,9 @@ struct tegra_vi_channel {
 	enum tegra_vi_pg_mode pg_mode;
 
 	struct v4l2_async_notifier notifier;
+
+	bool hflip:1;
+	bool vflip:1;
 };
 
 /**