linux-kernel - [PATCH v8 09/10] media: imagination: Round to closest multiple for cropping region

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Date: Fri, 17 May 2024 23:08:36 +0530
From: Devarsh Thakkar <devarsht@...com>
To: <mchehab@...nel.org>, <hverkuil-cisco@...all.nl>,
        <linux-media@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <benjamin.gaignard@...labora.com>, <sebastian.fricke@...labora.com>,
        <dri-devel@...ts.freedesktop.org>
CC: <laurent.pinchart@...asonboard.com>, <praneeth@...com>, <nm@...com>,
        <vigneshr@...com>, <a-bhatia1@...com>, <j-luthra@...com>,
        <b-brnich@...com>, <detheridge@...com>, <p-mantena@...com>,
        <vijayp@...com>, <devarsht@...com>, <andrzej.p@...labora.com>,
        <nicolas@...fresne.ca>, <p.zabel@...gutronix.de>, <airlied@...il.com>,
        <daniel@...ll.ch>, <akpm@...ux-foundation.org>,
        <gregkh@...uxfoundation.org>, <andriy.shevchenko@...ux.intel.com>,
        <adobriyan@...il.com>, <jani.nikula@...el.com>
Subject: [PATCH v8 09/10] media: imagination: Round to closest multiple for cropping region

If neither of the flags to round down (V4L2_SEL_FLAG_LE) or round up
(V4L2_SEL_FLAG_GE) are specified by the user, then round to nearest
multiple of requested value while updating the crop rectangle coordinates.

Use the rounding macro which gives preference to rounding down in case two
nearest values (high and low) are possible to raise the probability of
cropping rectangle falling inside the bound region.

This complies with the VIDIOC_G_SELECTION, VIDIOC_S_SELECTION ioctl
description as documented in v4l uapi [1] which specifies that driver
should choose crop rectangle as close as possible if no flags are passed by
user-space, as quoted below :

"``0`` - The driver can adjust the rectangle size freely and shall choose a
crop/compose rectangle as close as possible to the requested
 one."

[1] :
https://www.kernel.org/doc/Documentation/userspace-api/media/v4l/vidioc-g-selection.rst

Signed-off-by: Devarsh Thakkar <devarsht@...com>
---
V8: Update commit message with specification reference
V1->V7 (No change, patch introduced in V7)
---
 drivers/media/platform/imagination/e5010-jpeg-enc.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/media/platform/imagination/e5010-jpeg-enc.c b/drivers/media/platform/imagination/e5010-jpeg-enc.c
index 189e2a99c43d..abd66bc9b96c 100644
--- a/drivers/media/platform/imagination/e5010-jpeg-enc.c
+++ b/drivers/media/platform/imagination/e5010-jpeg-enc.c
@@ -517,10 +517,10 @@ static int e5010_s_selection(struct file *file, void *fh, struct v4l2_selection
 
 	switch (s->flags) {
 	case 0:
-		s->r.width = round_down(s->r.width, queue->fmt->frmsize.step_width);
-		s->r.height = round_down(s->r.height, queue->fmt->frmsize.step_height);
-		s->r.left = round_down(s->r.left, queue->fmt->frmsize.step_width);
-		s->r.top = round_down(s->r.top, 2);
+		s->r.width = round_closest_down(s->r.width, queue->fmt->frmsize.step_width);
+		s->r.height = round_closest_down(s->r.height, queue->fmt->frmsize.step_height);
+		s->r.left = round_closest_down(s->r.left, queue->fmt->frmsize.step_width);
+		s->r.top = round_closest_down(s->r.top, 2);
 
 		if (s->r.left + s->r.width > queue->width)
 			s->r.width = round_down(s->r.width + s->r.left - queue->width,
-- 
2.39.1