media: ti-vpe: cal: Drop V4L2_CAP_READWRITE

The V4L2 read/write API is inefficient and makes little sense for
devices that handle frame-based formats. Applications shouldn't use it,
drop its support from the driver.
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Benoit Parrot <bparrot@ti.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

drivers/media/platform/ti-vpe/cal-video.c

@@ -393,7 +393,6 @@ static const struct v4l2_file_operations cal_fops = {
 	.owner		= THIS_MODULE,
 	.open           = v4l2_fh_open,
 	.release        = vb2_fop_release,
-	.read           = vb2_fop_read,
 	.poll		= vb2_fop_poll,
 	.unlocked_ioctl = video_ioctl2, /* V4L2 ioctl handler */
 	.mmap           = vb2_fop_mmap,
@@ -595,8 +594,7 @@ static const struct video_device cal_videodev = {
 	.ioctl_ops	= &cal_ioctl_ops,
 	.minor		= -1,
 	.release	= video_device_release_empty,
-	.device_caps	= V4L2_CAP_VIDEO_CAPTURE | V4L2_CAP_STREAMING |
-			  V4L2_CAP_READWRITE,
+	.device_caps	= V4L2_CAP_VIDEO_CAPTURE | V4L2_CAP_STREAMING,
 };
 
 static int cal_ctx_v4l2_init_formats(struct cal_ctx *ctx)
@@ -731,7 +729,7 @@ int cal_ctx_v4l2_init(struct cal_ctx *ctx)
 
 	/* Initialize the vb2 queue. */
 	q->type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
-	q->io_modes = VB2_MMAP | VB2_DMABUF | VB2_READ;
+	q->io_modes = VB2_MMAP | VB2_DMABUF;
 	q->drv_priv = ctx;
 	q->buf_struct_size = sizeof(struct cal_buffer);
 	q->ops = &cal_video_qops;