media: i2c: imx296: Add horizontal/vertical flip support

Add support for setting horizontal and/or vertial flips in the IMX296
sensor through the V4L2_CID_HFLIP and V4L2_CID_VFLIP controls.

Add a new helper function to return the media bus format code that
depends on the sensor flips.

Grab the V4L2_CID_HFLIP and V4L2_CID_VFLIP controls on stream on, and
release on stream off to ensure flips cannot be changed while the sensor
is streaming.

Signed-off-by: Naushir Patuck <naush@raspberrypi.com>

drivers/media/i2c/imx296.c

@@ -212,6 +212,8 @@ struct imx296 {
 	struct v4l2_ctrl_handler ctrls;
 	struct v4l2_ctrl *hblank;
 	struct v4l2_ctrl *vblank;
+	struct v4l2_ctrl *vflip;
+	struct v4l2_ctrl *hflip;
 };
 
 static inline struct imx296 *to_imx296(struct v4l2_subdev *sd)
@@ -253,6 +255,36 @@ static int imx296_write(struct imx296 *sensor, u32 addr, u32 value, int *err)
 	return ret;
 }
 
+/*
+ * The supported formats.
+ * This table MUST contain 4 entries per format, to cover the various flip
+ * combinations in the order
+ * - no flip
+ * - h flip
+ * - v flip
+ * - h&v flips
+ */
+static const u32 mbus_codes[] = {
+	/* 10-bit modes. */
+	MEDIA_BUS_FMT_SRGGB10_1X10,
+	MEDIA_BUS_FMT_SGRBG10_1X10,
+	MEDIA_BUS_FMT_SGBRG10_1X10,
+	MEDIA_BUS_FMT_SBGGR10_1X10,
+};
+
+static u32 imx296_mbus_code(const struct imx296 *sensor)
+{
+	unsigned int i = 0;
+
+	if (sensor->mono)
+		return MEDIA_BUS_FMT_Y10_1X10;
+
+	if (sensor->vflip && sensor->hflip)
+		i = (sensor->vflip->val ? 2 : 0) | (sensor->hflip->val ? 1 : 0);
+
+	return mbus_codes[i];
+}
+
 static int imx296_power_on(struct imx296 *sensor)
 {
 	int ret;
@@ -347,6 +379,13 @@ static int imx296_s_ctrl(struct v4l2_ctrl *ctrl)
 			     &ret);
 		break;
 
+	case V4L2_CID_HFLIP:
+	case V4L2_CID_VFLIP:
+		imx296_write(sensor, IMX296_CTRL0E,
+			     sensor->vflip->val | (sensor->hflip->val << 1),
+			     &ret);
+		break;
+
 	case V4L2_CID_TEST_PATTERN:
 		if (ctrl->val) {
 			imx296_write(sensor, IMX296_PGHPOS, 8, &ret);
@@ -432,6 +471,16 @@ static int imx296_ctrls_init(struct imx296 *sensor)
 			  V4L2_CID_ANALOGUE_GAIN, IMX296_GAIN_MIN,
 			  IMX296_GAIN_MAX, 1, IMX296_GAIN_MIN);
 
+	sensor->hflip = v4l2_ctrl_new_std(&sensor->ctrls, &imx296_ctrl_ops,
+					  V4L2_CID_HFLIP, 0, 1, 1, 0);
+	if (sensor->hflip && !sensor->mono)
+		sensor->hflip->flags |= V4L2_CTRL_FLAG_MODIFY_LAYOUT;
+
+	sensor->vflip = v4l2_ctrl_new_std(&sensor->ctrls, &imx296_ctrl_ops,
+					  V4L2_CID_VFLIP, 0, 1, 1, 0);
+	if (sensor->vflip && !sensor->mono)
+		sensor->vflip->flags |= V4L2_CTRL_FLAG_MODIFY_LAYOUT;
+
 	imx296_setup_hblank(sensor, IMX296_PIXEL_ARRAY_WIDTH);
 
 	sensor->vblank = v4l2_ctrl_new_std(&sensor->ctrls, &imx296_ctrl_ops,
@@ -609,6 +658,10 @@ static int imx296_stream_on(struct imx296 *sensor)
 
 	imx296_write(sensor, IMX296_CTRL0A, 0, &ret);
 
+	/* vflip and hflip cannot change during streaming */
+	__v4l2_ctrl_grab(sensor->vflip, 1);
+	__v4l2_ctrl_grab(sensor->hflip, 1);
+
 	return ret;
 }
 
@@ -619,6 +672,9 @@ static int imx296_stream_off(struct imx296 *sensor)
 	imx296_write(sensor, IMX296_CTRL0A, IMX296_CTRL0A_XMSTA, &ret);
 	imx296_write(sensor, IMX296_CTRL00, IMX296_CTRL00_STANDBY, &ret);
 
+	__v4l2_ctrl_grab(sensor->vflip, 0);
+	__v4l2_ctrl_grab(sensor->hflip, 0);
+
 	return ret;
 }
 
@@ -678,8 +734,7 @@ static int imx296_enum_mbus_code(struct v4l2_subdev *sd,
 	if (code->index != 0)
 		return -EINVAL;
 
-	code->code = sensor->mono ? MEDIA_BUS_FMT_Y10_1X10
+	code->code = imx296_mbus_code(sensor);
-		   : MEDIA_BUS_FMT_SBGGR10_1X10;
 
 	return 0;
 }
@@ -689,6 +744,7 @@ static int imx296_enum_frame_size(struct v4l2_subdev *sd,
 				  struct v4l2_subdev_frame_size_enum *fse)
 {
 	const struct v4l2_mbus_framefmt *format;
+	struct imx296 *sensor = to_imx296(sd);
 
 	format = v4l2_subdev_state_get_format(state, fse->pad);
 
@@ -696,7 +752,7 @@ static int imx296_enum_frame_size(struct v4l2_subdev *sd,
 	 * Binning does not seem to work on either mono or colour sensor
 	 * variants. Disable enumerating the binned frame size for now.
 	 */
-	if (fse->index >= 1 || fse->code != format->code)
+	if (fse->index >= 1 || fse->code != imx296_mbus_code(sensor))
 		return -EINVAL;
 
 	fse->min_width = IMX296_PIXEL_ARRAY_WIDTH / (fse->index + 1);
@@ -723,8 +779,7 @@ static int imx296_set_format(struct v4l2_subdev *sd,
 
 	imx296_setup_hblank(sensor, format->width);
 
-	format->code = sensor->mono ? MEDIA_BUS_FMT_Y10_1X10
+	format->code = imx296_mbus_code(sensor);
-		     : MEDIA_BUS_FMT_SBGGR10_1X10;
 	format->field = V4L2_FIELD_NONE;
 	format->colorspace = V4L2_COLORSPACE_RAW;
 	format->ycbcr_enc = V4L2_YCBCR_ENC_DEFAULT;