media: v4l2-common: Add an helper to apply frmsize constraints

The rockchip VPU driver is open-coding this logic which seems pretty
generic. Let's provide an helper to apply the min/max and alignment
constraints on width/height.
Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

drivers/media/v4l2-core/v4l2-common.c

@@ -321,6 +321,16 @@ static unsigned int clamp_align(unsigned int x, unsigned int min,
 	return x;
 }
 
+static unsigned int clamp_roundup(unsigned int x, unsigned int min,
+				   unsigned int max, unsigned int alignment)
+{
+	x = clamp(x, min, max);
+	if (alignment)
+		x = round_up(x, alignment);
+
+	return x;
+}
+
 void v4l_bound_align_image(u32 *w, unsigned int wmin, unsigned int wmax,
 			   unsigned int walign,
 			   u32 *h, unsigned int hmin, unsigned int hmax,
@@ -531,6 +541,23 @@ static inline unsigned int v4l2_format_block_height(const struct v4l2_format_inf
 	return info->block_h[plane];
 }
 
+void v4l2_apply_frmsize_constraints(u32 *width, u32 *height,
+				    const struct v4l2_frmsize_stepwise *frmsize)
+{
+	if (!frmsize)
+		return;
+
+	/*
+	 * Clamp width/height to meet min/max constraints and round it up to
+	 * macroblock alignment.
+	 */
+	*width = clamp_roundup(*width, frmsize->min_width, frmsize->max_width,
+			       frmsize->step_width);
+	*height = clamp_roundup(*height, frmsize->min_height, frmsize->max_height,
+				frmsize->step_height);
+}
+EXPORT_SYMBOL_GPL(v4l2_apply_frmsize_constraints);
+
 int v4l2_fill_pixfmt_mp(struct v4l2_pix_format_mplane *pixfmt,
 			u32 pixelformat, u32 width, u32 height)
 {

include/media/v4l2-common.h

@@ -420,6 +420,8 @@ struct v4l2_format_info {
 
 const struct v4l2_format_info *v4l2_format_info(u32 format);
 
+void v4l2_apply_frmsize_constraints(u32 *width, u32 *height,
+				    const struct v4l2_frmsize_stepwise *frmsize);
 int v4l2_fill_pixfmt(struct v4l2_pix_format *pixfmt, u32 pixelformat,
 		     u32 width, u32 height);
 int v4l2_fill_pixfmt_mp(struct v4l2_pix_format_mplane *pixfmt, u32 pixelformat,