linux-kernel - [PATCH v2 2/3] media: dw100: Implement dynamic vertex map update

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Message-Id: <20260122-sklug-v6-16-topic-dw100-v3-1-dev-v2-2-ea1e29f18cf1@ideasonboard.com>
Date: Thu, 22 Jan 2026 15:44:57 +0100
From: Stefan Klug <stefan.klug@...asonboard.com>
To: Xavier Roumegue <xavier.roumegue@....nxp.com>, 
 Mauro Carvalho Chehab <mchehab@...nel.org>, 
 Sebastian Andrzej Siewior <bigeasy@...utronix.de>, 
 Clark Williams <clrkwllms@...nel.org>, Steven Rostedt <rostedt@...dmis.org>, 
 Laurent Pinchart <laurent.pinchart@...asonboard.com>
Cc: linux-media@...r.kernel.org, linux-kernel@...r.kernel.org, 
 linux-rt-devel@...ts.linux.dev, Nicolas Dufresne <nicolas@...fresne.ca>, 
 Stefan Klug <stefan.klug@...asonboard.com>
Subject: [PATCH v2 2/3] media: dw100: Implement dynamic vertex map update

Implement dynamic vertex map updates by handling the
V4L2_CID_DW100_DEWARPING_16x16_VERTEX_MAP control during streaming. This
allows to implement features like dynamic zoom, pan, rotate and dewarp.

To stay compatible with the old version, updates of
V4L2_CID_DW100_DEWARPING_16x16_VERTEX_MAP are ignored during streaming
when requests are not used. Print a corresponding warning once.

Signed-off-by: Stefan Klug <stefan.klug@...asonboard.com>

---

Changes in v2:
- Replaced the manual warn once by dev_warn_once(). This changes the
  frequency from once per context to once per boot which was agreed to
  be enough.
- Renamed user_map_needs_update to user_map_is_dirty as it is more
  expressive and fits to user_map_is_set
- Fixed indentation issue found by Media CI
---
 drivers/media/platform/nxp/dw100/dw100.c | 24 ++++++++++++++++++------
 1 file changed, 18 insertions(+), 6 deletions(-)

diff --git a/drivers/media/platform/nxp/dw100/dw100.c b/drivers/media/platform/nxp/dw100/dw100.c
index 1cb895da9912371a2b23ca62412c572d9cb75c00..d2b1c62b52db47ea1d2242caaf334fff30c6f366 100644
--- a/drivers/media/platform/nxp/dw100/dw100.c
+++ b/drivers/media/platform/nxp/dw100/dw100.c
@@ -98,6 +98,7 @@ struct dw100_ctx {
 	unsigned int			map_width;
 	unsigned int			map_height;
 	bool				user_map_is_set;
+	bool				user_map_is_dirty;
 
 	/* Source and destination queue data */
 	struct dw100_q_data		q_data[2];
@@ -293,11 +294,15 @@ static u32 dw100_map_format_coordinates(u16 xq, u16 yq)
 	return (u32)((yq << 16) | xq);
 }
 
-static u32 *dw100_get_user_map(struct dw100_ctx *ctx)
+static void dw100_update_mapping(struct dw100_ctx *ctx)
 {
 	struct v4l2_ctrl *ctrl = ctx->ctrls[DW100_CTRL_DEWARPING_MAP];
 
-	return ctrl->p_cur.p_u32;
+	if (!ctx->user_map_is_dirty)
+		return;
+
+	memcpy(ctx->map, ctrl->p_cur.p_u32, ctx->map_size);
+	ctx->user_map_is_dirty = false;
 }
 
 /*
@@ -306,8 +311,6 @@ static u32 *dw100_get_user_map(struct dw100_ctx *ctx)
  */
 static int dw100_create_mapping(struct dw100_ctx *ctx)
 {
-	u32 *user_map;
-
 	if (ctx->map)
 		dma_free_coherent(&ctx->dw_dev->pdev->dev, ctx->map_size,
 				  ctx->map, ctx->map_dma);
@@ -318,8 +321,8 @@ static int dw100_create_mapping(struct dw100_ctx *ctx)
 	if (!ctx->map)
 		return -ENOMEM;
 
-	user_map = dw100_get_user_map(ctx);
-	memcpy(ctx->map, user_map, ctx->map_size);
+	ctx->user_map_is_dirty = true;
+	dw100_update_mapping(ctx);
 
 	dev_dbg(&ctx->dw_dev->pdev->dev,
 		"%ux%u %s mapping created (d:%pad-c:%p) for stream %ux%u->%ux%u\n",
@@ -351,6 +354,7 @@ static int dw100_s_ctrl(struct v4l2_ctrl *ctrl)
 	switch (ctrl->id) {
 	case V4L2_CID_DW100_DEWARPING_16x16_VERTEX_MAP:
 		ctx->user_map_is_set = true;
+		ctx->user_map_is_dirty = true;
 		break;
 	}
 
@@ -405,6 +409,7 @@ static void dw100_ctrl_dewarping_map_init(const struct v4l2_ctrl *ctrl,
 	}
 
 	ctx->user_map_is_set = false;
+	ctx->user_map_is_dirty = true;
 }
 
 static const struct v4l2_ctrl_type_ops dw100_ctrl_type_ops = {
@@ -1478,6 +1483,13 @@ static void dw100_device_run(void *priv)
 	v4l2_ctrl_request_setup(src_buf->vb2_buf.req_obj.req,
 				&ctx->hdl);
 
+	if (src_buf->vb2_buf.req_obj.req)
+		dw100_update_mapping(ctx);
+	else if (ctx->user_map_is_dirty)
+		dev_warn_once(&ctx->dw_dev->pdev->dev,
+			      "V4L2 requests are required to update the vertex map dynamically"
+		);
+
 	v4l2_ctrl_request_complete(src_buf->vb2_buf.req_obj.req,
 				   &ctx->hdl);
 

-- 
2.51.0