soc-camera: V4L2 API compliant scaling (S_FMT) and cropping (S_CROP)

From: Guennadi Liakhovetski <g.liakhovetski@gmx.de>

The initial soc-camera scaling and cropping implementation turned out to be
incompliant with the V4L2 API, e.g., it expected the user to specify cropping
in output window pixels, instead of input window pixels. This patch converts
the soc-camera core and all drivers to comply with the standard.

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Priority: low

1 files changed, 75 insertions, 55 deletions

diff --git a/linux/drivers/media/video/soc_camera.c b/linux/drivers/media/video/soc_camera.c
index 6145846f7..2290118fb 100644
--- a/linux/drivers/media/video/soc_camera.c
+++ b/linux/drivers/media/video/soc_camera.c
@@ -279,6 +279,9 @@ static void soc_camera_free_user_formats(struct soc_camera_device *icd)
 	icd->user_formats = NULL;
 }
 
+#define pixfmtstr(x) (x) & 0xff, ((x) >> 8) & 0xff, ((x) >> 16) & 0xff, \
+	((x) >> 24) & 0xff
+
 /* Called with .vb_lock held */
 static int soc_camera_set_fmt(struct soc_camera_file *icf,
 			      struct v4l2_format *f)
@@ -288,6 +291,9 @@ static int soc_camera_set_fmt(struct soc_camera_file *icf,
 	struct v4l2_pix_format *pix = &f->fmt.pix;
 	int ret;
 
+	dev_dbg(&icd->dev, "S_FMT(%c%c%c%c, %ux%u)\n",
+		pixfmtstr(pix->pixelformat), pix->width, pix->height);
+
 	/* We always call try_fmt() before set_fmt() or set_crop() */
 	ret = ici->ops->try_fmt(icd, f);
 	if (ret < 0)
@@ -303,17 +309,17 @@ static int soc_camera_set_fmt(struct soc_camera_file *icf,
 		return -EINVAL;
 	}
 
-	icd->rect_current.width		= pix->width;
-	icd->rect_current.height	= pix->height;
-	icf->vb_vidq.field		=
-		icd->field		= pix->field;
+	icd->user_width		= pix->width;
+	icd->user_height	= pix->height;
+	icf->vb_vidq.field	=
+		icd->field	= pix->field;
 
 	if (f->type != V4L2_BUF_TYPE_VIDEO_CAPTURE)
 		dev_warn(&icd->dev, "Attention! Wrong buf-type %d\n",
 			 f->type);
 
 	dev_dbg(&icd->dev, "set width: %d height: %d\n",
-		icd->rect_current.width, icd->rect_current.height);
+		icd->user_width, icd->user_height);
 
 	/* set physical bus parameters */
 	return ici->ops->set_bus_param(icd, pix->pixelformat);
@@ -356,8 +362,8 @@ static int soc_camera_open(struct file *file)
 		struct v4l2_format f = {
 			.type = V4L2_BUF_TYPE_VIDEO_CAPTURE,
 			.fmt.pix = {
-				.width		= icd->rect_current.width,
-				.height		= icd->rect_current.height,
+				.width		= icd->user_width,
+				.height		= icd->user_height,
 				.field		= icd->field,
 				.pixelformat	= icd->current_fmt->fourcc,
 				.colorspace	= icd->current_fmt->colorspace,
@@ -558,8 +564,8 @@ static int soc_camera_g_fmt_vid_cap(struct file *file, void *priv,
 
 	WARN_ON(priv != file->private_data);
 
-	pix->width		= icd->rect_current.width;
-	pix->height		= icd->rect_current.height;
+	pix->width		= icd->user_width;
+	pix->height		= icd->user_height;
 	pix->field		= icf->vb_vidq.field;
 	pix->pixelformat	= icd->current_fmt->fourcc;
 	pix->bytesperline	= pix->width *
@@ -723,17 +729,9 @@ static int soc_camera_cropcap(struct file *file, void *fh,
 {
 	struct soc_camera_file *icf = file->private_data;
 	struct soc_camera_device *icd = icf->icd;
+	struct soc_camera_host *ici = to_soc_camera_host(icd->dev.parent);
 
-	a->type				= V4L2_BUF_TYPE_VIDEO_CAPTURE;
-	a->bounds			= icd->rect_max;
-	a->defrect.left			= icd->rect_max.left;
-	a->defrect.top			= icd->rect_max.top;
-	a->defrect.width		= DEFAULT_WIDTH;
-	a->defrect.height		= DEFAULT_HEIGHT;
-	a->pixelaspect.numerator	= 1;
-	a->pixelaspect.denominator	= 1;
-
-	return 0;
+	return ici->ops->cropcap(icd, a);
 }
 
 static int soc_camera_g_crop(struct file *file, void *fh,
@@ -741,11 +739,14 @@ static int soc_camera_g_crop(struct file *file, void *fh,
 {
 	struct soc_camera_file *icf = file->private_data;
 	struct soc_camera_device *icd = icf->icd;
+	struct soc_camera_host *ici = to_soc_camera_host(icd->dev.parent);
+	int ret;
 
-	a->type	= V4L2_BUF_TYPE_VIDEO_CAPTURE;
-	a->c	= icd->rect_current;
+	mutex_lock(&icf->vb_vidq.vb_lock);
+	ret = ici->ops->get_crop(icd, a);
+	mutex_unlock(&icf->vb_vidq.vb_lock);
 
-	return 0;
+	return ret;
 }
 
 /*
@@ -760,49 +761,33 @@ static int soc_camera_s_crop(struct file *file, void *fh,
 	struct soc_camera_file *icf = file->private_data;
 	struct soc_camera_device *icd = icf->icd;
 	struct soc_camera_host *ici = to_soc_camera_host(icd->dev.parent);
-	struct v4l2_rect rect = a->c;
+	struct v4l2_rect *rect = &a->c;
+	struct v4l2_crop current_crop;
 	int ret;
 
 	if (a->type != V4L2_BUF_TYPE_VIDEO_CAPTURE)
 		return -EINVAL;
 
+	dev_dbg(&icd->dev, "S_CROP(%ux%u@%u:%u)\n",
+		rect->width, rect->height, rect->left, rect->top);
+
 	/* Cropping is allowed during a running capture, guard consistency */
 	mutex_lock(&icf->vb_vidq.vb_lock);
 
+	/* If get_crop fails, we'll let host and / or client drivers decide */
+	ret = ici->ops->get_crop(icd, &current_crop);
+
 	/* Prohibit window size change with initialised buffers */
-	if (icf->vb_vidq.bufs[0] && (rect.width != icd->rect_current.width ||
-				     rect.height != icd->rect_current.height)) {
+	if (icf->vb_vidq.bufs[0] && !ret &&
+	    (a->c.width != current_crop.c.width ||
+	     a->c.height != current_crop.c.height)) {
 		dev_err(&icd->dev,
 			"S_CROP denied: queue initialised and sizes differ\n");
 		ret = -EBUSY;
-		goto unlock;
+	} else {
+		ret = ici->ops->set_crop(icd, a);
 	}
 
-	if (rect.width > icd->rect_max.width)
-		rect.width = icd->rect_max.width;
-
-	if (rect.width < icd->width_min)
-		rect.width = icd->width_min;
-
-	if (rect.height > icd->rect_max.height)
-		rect.height = icd->rect_max.height;
-
-	if (rect.height < icd->height_min)
-		rect.height = icd->height_min;
-
-	if (rect.width + rect.left > icd->rect_max.width + icd->rect_max.left)
-		rect.left = icd->rect_max.width + icd->rect_max.left -
-			rect.width;
-
-	if (rect.height + rect.top > icd->rect_max.height + icd->rect_max.top)
-		rect.top = icd->rect_max.height + icd->rect_max.top -
-			rect.height;
-
-	ret = ici->ops->set_crop(icd, a);
-	if (!ret)
-		icd->rect_current = rect;
-
-unlock:
 	mutex_unlock(&icf->vb_vidq.vb_lock);
 
 	return ret;
@@ -927,6 +912,8 @@ static int soc_camera_probe(struct device *dev)
 	struct soc_camera_host *ici = to_soc_camera_host(dev->parent);
 	struct soc_camera_link *icl = to_soc_camera_link(icd);
 	struct device *control = NULL;
+	struct v4l2_subdev *sd;
+	struct v4l2_format f = {.type = V4L2_BUF_TYPE_VIDEO_CAPTURE};
 	int ret;
 
 	dev_info(dev, "Probing %s\n", dev_name(dev));
@@ -983,7 +970,6 @@ static int soc_camera_probe(struct device *dev)
 	if (ret < 0)
 		goto eiufmt;
 
-	icd->rect_current = icd->rect_max;
 	icd->field = V4L2_FIELD_ANY;
 
 	/* ..._video_start() will create a device node, so we have to protect */
@@ -993,9 +979,15 @@ static int soc_camera_probe(struct device *dev)
 	if (ret < 0)
 		goto evidstart;
 
+	/* Try to improve our guess of a reasonable window format */
+	sd = soc_camera_to_subdev(icd);
+	if (!v4l2_subdev_call(sd, video, g_fmt, &f)) {
+		icd->user_width		= f.fmt.pix.width;
+		icd->user_height	= f.fmt.pix.height;
+	}
+
 	/* Do we have to sysfs_remove_link() before device_unregister()? */
-	if (to_soc_camera_control(icd) &&
-	    sysfs_create_link(&icd->dev.kobj, &to_soc_camera_control(icd)->kobj,
+	if (sysfs_create_link(&icd->dev.kobj, &to_soc_camera_control(icd)->kobj,
 			      "control"))
 		dev_warn(&icd->dev, "Failed creating the control symlink\n");
 
@@ -1104,6 +1096,25 @@ static void dummy_release(struct device *dev)
 {
 }
 
+static int default_cropcap(struct soc_camera_device *icd,
+			   struct v4l2_cropcap *a)
+{
+	struct v4l2_subdev *sd = soc_camera_to_subdev(icd);
+	return v4l2_subdev_call(sd, video, cropcap, a);
+}
+
+static int default_g_crop(struct soc_camera_device *icd, struct v4l2_crop *a)
+{
+	struct v4l2_subdev *sd = soc_camera_to_subdev(icd);
+	return v4l2_subdev_call(sd, video, g_crop, a);
+}
+
+static int default_s_crop(struct soc_camera_device *icd, struct v4l2_crop *a)
+{
+	struct v4l2_subdev *sd = soc_camera_to_subdev(icd);
+	return v4l2_subdev_call(sd, video, s_crop, a);
+}
+
 int soc_camera_host_register(struct soc_camera_host *ici)
 {
 	struct soc_camera_host *ix;
@@ -1112,7 +1123,6 @@ int soc_camera_host_register(struct soc_camera_host *ici)
 	if (!ici || !ici->ops ||
 	    !ici->ops->try_fmt ||
 	    !ici->ops->set_fmt ||
-	    !ici->ops->set_crop ||
 	    !ici->ops->set_bus_param ||
 	    !ici->ops->querycap ||
 	    !ici->ops->init_videobuf ||
@@ -1123,6 +1133,13 @@ int soc_camera_host_register(struct soc_camera_host *ici)
 	    !ici->v4l2_dev.dev)
 		return -EINVAL;
 
+	if (!ici->ops->set_crop)
+		ici->ops->set_crop = default_s_crop;
+	if (!ici->ops->get_crop)
+		ici->ops->get_crop = default_g_crop;
+	if (!ici->ops->cropcap)
+		ici->ops->cropcap = default_cropcap;
+
 	mutex_lock(&list_lock);
 	list_for_each_entry(ix, &hosts, list) {
 		if (ix->nr == ici->nr) {
@@ -1322,6 +1339,9 @@ static int __devinit soc_camera_pdrv_probe(struct platform_device *pdev)
 	if (ret < 0)
 		goto escdevreg;
 
+	icd->user_width		= DEFAULT_WIDTH;
+	icd->user_height	= DEFAULT_HEIGHT;
+
 	return 0;
 
 escdevreg: