media: rkisp1: Add RKISP1_CID_SUPPORTED_PARAMS_BLOCKS control

Add a RKISP1_CID_SUPPORTED_PARAMS_BLOCKS V4L2 control to be able to
query the parameters blocks supported by the current kernel on the
current hardware from user space.

Signed-off-by: Stefan Klug <stefan.klug@ideasonboard.com>
Reviewed-by: Paul Elder <paul.elder@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Link: https://lore.kernel.org/r/20250523-supported-params-and-wdr-v3-2-7283b8536694@ideasonboard.com
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>

drivers/media/platform/rockchip/rkisp1/rkisp1-common.h

@@ -415,6 +415,8 @@ struct rkisp1_params {
 	spinlock_t config_lock; /* locks the buffers list 'params' */
 	struct list_head params;
 
+	struct v4l2_ctrl_handler ctrls;
+
 	const struct v4l2_meta_format *metafmt;
 
 	enum v4l2_quantization quantization;

drivers/media/platform/rockchip/rkisp1/rkisp1-params.c

@@ -2736,6 +2736,44 @@ static int rkisp1_params_init_vb2_queue(struct vb2_queue *q,
 	return vb2_queue_init(q);
 }
 
+static int rkisp1_params_ctrl_init(struct rkisp1_params *params)
+{
+	struct v4l2_ctrl_config ctrl_config = {
+		.id = RKISP1_CID_SUPPORTED_PARAMS_BLOCKS,
+		.name = "Supported Params Blocks",
+		.type = V4L2_CTRL_TYPE_BITMASK,
+		.flags = V4L2_CTRL_FLAG_READ_ONLY,
+	};
+	int ret;
+
+	v4l2_ctrl_handler_init(&params->ctrls, 1);
+
+	for (unsigned int i = 0; i < ARRAY_SIZE(rkisp1_ext_params_handlers); i++) {
+		const struct rkisp1_ext_params_handler *block_handler;
+
+		block_handler = &rkisp1_ext_params_handlers[i];
+		ctrl_config.max |= BIT(i);
+
+		if ((params->rkisp1->info->features & block_handler->features) !=
+		    block_handler->features)
+			continue;
+
+		ctrl_config.def |= BIT(i);
+	}
+
+	v4l2_ctrl_new_custom(&params->ctrls, &ctrl_config, NULL);
+
+	params->vnode.vdev.ctrl_handler = &params->ctrls;
+
+	if (params->ctrls.error) {
+		ret = params->ctrls.error;
+		v4l2_ctrl_handler_free(&params->ctrls);
+		return ret;
+	}
+
+	return 0;
+}
+
 int rkisp1_params_register(struct rkisp1_device *rkisp1)
 {
 	struct rkisp1_params *params = &rkisp1->params;
@@ -2781,15 +2819,23 @@ int rkisp1_params_register(struct rkisp1_device *rkisp1)
 	if (ret)
 		goto err_media;
 
+	ret = rkisp1_params_ctrl_init(params);
+	if (ret) {
+		dev_err(rkisp1->dev, "Control initialization error %d\n", ret);
+		goto err_media;
+	}
+
 	ret = video_register_device(vdev, VFL_TYPE_VIDEO, -1);
 	if (ret) {
 		dev_err(rkisp1->dev,
 			"failed to register %s, ret=%d\n", vdev->name, ret);
-		goto err_media;
+		goto err_ctrl;
 	}
 
 	return 0;
 
+err_ctrl:
+	v4l2_ctrl_handler_free(&params->ctrls);
 err_media:
 	media_entity_cleanup(&vdev->entity);
 	mutex_destroy(&node->vlock);
@@ -2806,6 +2852,7 @@ void rkisp1_params_unregister(struct rkisp1_device *rkisp1)
 		return;
 
 	vb2_video_unregister_device(vdev);
+	v4l2_ctrl_handler_free(&params->ctrls);
 	media_entity_cleanup(&vdev->entity);
 	mutex_destroy(&node->vlock);
 }

include/uapi/linux/rkisp1-config.h

@@ -1086,6 +1086,9 @@ enum rkisp1_ext_params_block_type {
 #define RKISP1_EXT_PARAMS_FL_BLOCK_DISABLE	(1U << 0)
 #define RKISP1_EXT_PARAMS_FL_BLOCK_ENABLE	(1U << 1)
 
+/* A bitmask of parameters blocks supported on the current hardware. */
+#define RKISP1_CID_SUPPORTED_PARAMS_BLOCKS	(V4L2_CID_USER_RKISP1_BASE + 0x01)
+
 /**
  * struct rkisp1_ext_params_block_header - RkISP1 extensible parameters block
  *					   header
@@ -1520,6 +1523,14 @@ enum rksip1_ext_param_buffer_version {
  * V4L2 control. If such control is not available, userspace should assume only
  * RKISP1_EXT_PARAM_BUFFER_V1 is supported by the driver.
  *
+ * The read-only V4L2 control ``RKISP1_CID_SUPPORTED_PARAMS_BLOCKS`` can be used
+ * to query the blocks supported by the device. It contains a bitmask where each
+ * bit represents the availability of the corresponding entry from the
+ * :c:type:`rkisp1_ext_params_block_type` enum. The current and default values
+ * of the control represents the blocks supported by the device instance, while
+ * the maximum value represents the blocks supported by the kernel driver,
+ * independently of the device instance.
+ *
  * For each ISP block that userspace wants to configure, a block-specific
  * structure is appended to the @data buffer, one after the other without gaps
  * in between nor overlaps. Userspace shall populate the @data_size field with

include/uapi/linux/v4l2-controls.h

@@ -222,6 +222,12 @@ enum v4l2_colorfx {
  */
 #define V4L2_CID_USER_UVC_BASE			(V4L2_CID_USER_BASE + 0x11e0)
 
+/*
+ * The base for Rockchip ISP1 driver controls.
+ * We reserve 16 controls for this driver.
+ */
+#define V4L2_CID_USER_RKISP1_BASE		(V4L2_CID_USER_BASE + 0x1220)
+
 /* MPEG-class control IDs */
 /* The MPEG controls are applicable to all codec controls
  * and the 'MPEG' part of the define is historical */