Drivers are instead encouraged to use a helper such as
v4l2_async_notifier_add_i2c_subdev.

This fixes a misuse of the API, as v4l2_async_notifier_add_subdev
should get a kmalloc'ed struct v4l2_async_subdev,
removing some boilerplate code while at it.

Use the appropriate helper: v4l2_async_notifier_add_i2c_subdev
or v4l2_async_notifier_add_fwnode_remote_subdev, which handles
the needed setup, instead of open-coding it.

Using v4l2-async to allocate the driver-specific structs,
requires to change struct ceu_subdev so the embedded
struct v4l2_async_subdev is now the first element.

Signed-off-by: Ezequiel Garcia <redacted>
---
 drivers/media/platform/renesas-ceu.c | 89 ++++++++++------------------
 1 file changed, 31 insertions(+), 58 deletions(-)

diff --git a/drivers/media/platform/renesas-ceu.c b/drivers/media/platform/renesas-ceu.c
index 4a633ad0e8fa..18485812a21e 100644
--- a/drivers/media/platform/renesas-ceu.c
+++ b/drivers/media/platform/renesas-ceu.c

@@ -152,8 +152,8 @@ static inline struct ceu_buffer *vb2_to_ceu(struct vb2_v4l2_buffer *vbuf)
  * ceu_subdev - Wraps v4l2 sub-device and provides async subdevice.
  */
 struct ceu_subdev {
-	struct v4l2_subdev *v4l2_sd;
 	struct v4l2_async_subdev asd;
+	struct v4l2_subdev *v4l2_sd;
 
 	/* per-subdevice mbus configuration options */
 	unsigned int mbus_flags;

@@ -174,7 +174,7 @@ struct ceu_device {
 	struct v4l2_device	v4l2_dev;
 
 	/* subdevices descriptors */
-	struct ceu_subdev	*subdevs;
+	struct ceu_subdev	**subdevs;
 	/* the subdevice currently in use */
 	struct ceu_subdev	*sd;
 	unsigned int		sd_index;

@@ -1195,7 +1195,7 @@ static int ceu_enum_input(struct file *file, void *priv,
 	if (inp->index >= ceudev->num_sd)
 		return -EINVAL;
 
-	ceusd = &ceudev->subdevs[inp->index];
+	ceusd = ceudev->subdevs[inp->index];
 
 	inp->type = V4L2_INPUT_TYPE_CAMERA;
 	inp->std = 0;

@@ -1230,7 +1230,7 @@ static int ceu_s_input(struct file *file, void *priv, unsigned int i)
 		return 0;
 
 	ceu_sd_old = ceudev->sd;
-	ceudev->sd = &ceudev->subdevs[i];
+	ceudev->sd = ceudev->subdevs[i];
 
 	/*
 	 * Make sure we can generate output image formats and apply

@@ -1423,7 +1423,7 @@ static int ceu_notify_complete(struct v4l2_async_notifier *notifier)
 	 * ceu formats.
 	 */
 	if (!ceudev->sd) {
-		ceudev->sd = &ceudev->subdevs[0];
+		ceudev->sd = ceudev->subdevs[0];
 		ceudev->sd_index = 0;
 	}
 

@@ -1465,28 +1465,6 @@ static const struct v4l2_async_notifier_operations ceu_notify_ops = {
 	.complete	= ceu_notify_complete,
 };
 
-/*
- * ceu_init_async_subdevs() - Initialize CEU subdevices and async_subdevs in
- *			      ceu device. Both DT and platform data parsing use
- *			      this routine.
- *
- * Returns 0 for success, -ENOMEM for failure.
- */
-static int ceu_init_async_subdevs(struct ceu_device *ceudev, unsigned int n_sd)
-{
-	/* Reserve memory for 'n_sd' ceu_subdev descriptors. */
-	ceudev->subdevs = devm_kcalloc(ceudev->dev, n_sd,
-				       sizeof(*ceudev->subdevs), GFP_KERNEL);

-	if (!ceudev->subdevs)
-		return -ENOMEM;
-
-	ceudev->sd = NULL;
-	ceudev->sd_index = 0;
-	ceudev->num_sd = 0;
-
-	return 0;
-}
-
 /*
  * ceu_parse_platform_data() - Initialize async_subdevices using platform
  *			       device provided data.

@@ -1495,6 +1473,7 @@ static int ceu_parse_platform_data(struct ceu_device *ceudev,
 				   const struct ceu_platform_data *pdata)
 {
 	const struct ceu_async_subdev *async_sd;
+	struct v4l2_async_subdev *asd;
 	struct ceu_subdev *ceu_sd;
 	unsigned int i;
 	int ret;

@@ -1502,29 +1481,26 @@ static int ceu_parse_platform_data(struct ceu_device *ceudev,
 	if (pdata->num_subdevs == 0)
 		return -ENODEV;
 
-	ret = ceu_init_async_subdevs(ceudev, pdata->num_subdevs);
-	if (ret)
-		return ret;
+	ceudev->sd = NULL;
+	ceudev->sd_index = 0;
+	ceudev->num_sd = 0;

 
 	for (i = 0; i < pdata->num_subdevs; i++) {
 
 		/* Setup the ceu subdevice and the async subdevice. */
 		async_sd = &pdata->subdevs[i];
-		ceu_sd = &ceudev->subdevs[i];
-
-		INIT_LIST_HEAD(&ceu_sd->asd.list);
-
-		ceu_sd->mbus_flags	= async_sd->flags;
-		ceu_sd->asd.match_type	= V4L2_ASYNC_MATCH_I2C;
-		ceu_sd->asd.match.i2c.adapter_id = async_sd->i2c_adapter_id;
-		ceu_sd->asd.match.i2c.address = async_sd->i2c_address;
-
-		ret = v4l2_async_notifier_add_subdev(&ceudev->notifier,
-						     &ceu_sd->asd);
-		if (ret) {
+		asd = v4l2_async_notifier_add_i2c_subdev(&ceudev->notifier,
+				async_sd->i2c_adapter_id,
+				async_sd->i2c_address,
+				sizeof(*ceu_sd));
+		if (IS_ERR(asd)) {
+			ret = PTR_ERR(asd);
 			v4l2_async_notifier_cleanup(&ceudev->notifier);
 			return ret;
 		}
+		ceu_sd = to_ceu_subdev(asd);
+		ceu_sd->mbus_flags = async_sd->flags;
+		ceudev->subdevs[i] = ceu_sd;
 	}
 
 	return pdata->num_subdevs;

@@ -1536,7 +1512,8 @@ static int ceu_parse_platform_data(struct ceu_device *ceudev,
 static int ceu_parse_dt(struct ceu_device *ceudev)
 {
 	struct device_node *of = ceudev->dev->of_node;
-	struct device_node *ep, *remote;
+	struct device_node *ep;
+	struct v4l2_async_subdev *asd;
 	struct ceu_subdev *ceu_sd;
 	unsigned int i;
 	int num_ep;

@@ -1546,9 +1523,9 @@ static int ceu_parse_dt(struct ceu_device *ceudev)
 	if (!num_ep)
 		return -ENODEV;
 
-	ret = ceu_init_async_subdevs(ceudev, num_ep);
-	if (ret)
-		return ret;
+	ceudev->sd = NULL;
+	ceudev->sd_index = 0;
+	ceudev->num_sd = 0;

 
 	for (i = 0; i < num_ep; i++) {
 		struct v4l2_fwnode_endpoint fw_ep = {

@@ -1578,20 +1555,16 @@ static int ceu_parse_dt(struct ceu_device *ceudev)
 		}
 
 		/* Setup the ceu subdevice and the async subdevice. */
-		ceu_sd = &ceudev->subdevs[i];
-		INIT_LIST_HEAD(&ceu_sd->asd.list);
-
-		remote = of_graph_get_remote_port_parent(ep);
-		ceu_sd->mbus_flags = fw_ep.bus.parallel.flags;
-		ceu_sd->asd.match_type = V4L2_ASYNC_MATCH_FWNODE;
-		ceu_sd->asd.match.fwnode = of_fwnode_handle(remote);
-
-		ret = v4l2_async_notifier_add_subdev(&ceudev->notifier,
-						     &ceu_sd->asd);
-		if (ret) {
-			of_node_put(remote);
+		asd = v4l2_async_notifier_add_fwnode_remote_subdev(
+				&ceudev->notifier, of_fwnode_handle(ep),
+				sizeof(*ceu_sd));
+		if (IS_ERR(asd)) {
+			ret = PTR_ERR(asd);
 			goto error_cleanup;
 		}
+		ceu_sd = to_ceu_subdev(asd);
+		ceu_sd->mbus_flags = fw_ep.bus.parallel.flags;
+		ceudev->subdevs[i] = ceu_sd;
 
 		of_node_put(ep);
 	}