Hi Hans,

Thanks for the review.

On Mon, Sep 11, 2017 at 11:38:58AM +0200, Hans Verkuil wrote:

Typo in subject: interger -> integer

On 09/11/2017 10:00 AM, Sakari Ailus wrote:

quoted

v4l2_fwnode_reference_parse_int_prop() will find an fwnode such that under
the device's own fwnode, 

Sorry, you lost me here. Which device are we talking about?

The fwnode related a struct device, in other words what dev_fwnode(dev)
gives you. This is either struct device.fwnode or struct
device.of_node.fwnode, depending on which firmware interface was used to
create the device.

I'll add a note of this.

quoted

it will follow child fwnodes with the given
property -- value pair and return the resulting fwnode.

property-value pair (easier readable that way).

You only describe v4l2_fwnode_reference_parse_int_prop(), not
v4l2_fwnode_reference_parse_int_props().

Yes, I think I changed the naming but forgot to update the commit. I'll do
that now.

quoted

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
---
 drivers/media/v4l2-core/v4l2-fwnode.c | 93 +++++++++++++++++++++++++++++++++++
 1 file changed, 93 insertions(+)

diff --git a/drivers/media/v4l2-core/v4l2-fwnode.c b/drivers/media/v4l2-core/v4l2-fwnode.c
index 4821c4989119..56eee5bbd3b5 100644
--- a/drivers/media/v4l2-core/v4l2-fwnode.c
+++ b/drivers/media/v4l2-core/v4l2-fwnode.c

@@ -496,6 +496,99 @@ static int v4l2_fwnode_reference_parse(
 	return ret;
 }
 
+static struct fwnode_handle *v4l2_fwnode_reference_get_int_prop(
+	struct fwnode_handle *fwnode, const char *prop, unsigned int index,
+	const char **props, unsigned int nprops)

Need comments describing what this does.

Yes. I'll also rename it (get -> read) for consistency with the async
changes.

quoted

+{
+	struct fwnode_reference_args fwnode_args;
+	unsigned int *args = fwnode_args.args;
+	struct fwnode_handle *child;
+	int ret;
+
+	ret = fwnode_property_get_reference_args(fwnode, prop, NULL, nprops,
+						 index, &fwnode_args);
+	if (ret)
+		return ERR_PTR(ret == -EINVAL ? -ENOENT : ret);

Why map EINVAL to ENOENT? Needs a comment, either here or in the function description.

fwnode_property_get_reference_args() returns currently a little bit
different error codes in ACPI / DT. This is worth documenting there and
fixing as well.

quoted

+
+	for (fwnode = fwnode_args.fwnode;
+	     nprops; nprops--, fwnode = child, props++, args++) {

I think you cram too much in this for-loop: fwnode, nprops, fwnode, props, args...
It's hard to parse.

Hmm. I'm not sure if that really helps; the function is just handling each
entry in the array and related array pointers are changed accordingly. The
fwnode = child assignment is there to move to the child node. I.e. what you
need for handling the loop itself.

I can change this though if you think it really makes a difference for
better.

I would make this a 'while (nprops)' and write out all the other assignments,
increments and decrements.

quoted

+		u32 val;
+
+		fwnode_for_each_child_node(fwnode, child) {
+			if (fwnode_property_read_u32(child, *props, &val))
+				continue;
+
+			if (val == *args)
+				break;

I'm lost. This really needs comments and perhaps even an DT or ACPI example
so you can see what exactly it is we're doing here.

I'll add comments to the code. A good example will be ACPI documentation
for LEDs, see 17th patch in v9. That will go through the linux-pm tree so
it won't be available in the same tree for a while.

quoted

+		}
+
+		fwnode_handle_put(fwnode);
+
+		if (!child) {
+			fwnode = ERR_PTR(-ENOENT);
+			break;
+		}
+	}
+
+	return fwnode;
+}
+
+static int v4l2_fwnode_reference_parse_int_props(
+	struct device *dev, struct v4l2_async_notifier *notifier,
+	const char *prop, const char **props, unsigned int nprops)

Needs comments describing what this does.

Will add.

quoted

+{
+	struct fwnode_handle *fwnode;
+	unsigned int index = 0;
+	int ret;
+
+	while (!IS_ERR((fwnode = v4l2_fwnode_reference_get_int_prop(
+				dev_fwnode(dev), prop, index, props,
+				nprops)))) {
+		fwnode_handle_put(fwnode);
+		index++;
+	}
+
+	if (PTR_ERR(fwnode) != -ENOENT)
+		return PTR_ERR(fwnode);

Missing 'if (index == 0)'?

Yes, will add.

quoted

+
+	ret = v4l2_async_notifier_realloc(notifier,
+					  notifier->num_subdevs + index);
+	if (ret)
+		return -ENOMEM;
+
+	for (index = 0; !IS_ERR((fwnode = v4l2_fwnode_reference_get_int_prop(
+					 dev_fwnode(dev), prop, index, props,
+					 nprops))); ) {

I'd add 'index++' in this for-loop. It's weird that it is missing.

Agreed, I'll move it there.

quoted

+		struct v4l2_async_subdev *asd;
+
+		if (WARN_ON(notifier->num_subdevs >= notifier->max_subdevs)) {
+			ret = -EINVAL;
+			goto error;
+		}
+
+		asd = kzalloc(sizeof(struct v4l2_async_subdev), GFP_KERNEL);
+		if (!asd) {
+			ret = -ENOMEM;
+			goto error;
+		}
+
+		notifier->subdevs[notifier->num_subdevs] = asd;
+		asd->match.fwnode.fwnode = fwnode;
+		asd->match_type = V4L2_ASYNC_MATCH_FWNODE;
+		notifier->num_subdevs++;
+
+		fwnode_handle_put(fwnode);
+
+		index++;
+	}
+
+	return PTR_ERR(fwnode) == -ENOENT ? 0 : PTR_ERR(fwnode);
+
+error:
+	fwnode_handle_put(fwnode);
+	return ret;
+}
+
 MODULE_LICENSE("GPL");
 MODULE_AUTHOR("Sakari Ailus [off-list ref]");
 MODULE_AUTHOR("Sylwester Nawrocki [off-list ref]");

-- 
Regards,

Sakari Ailus
e-mail: sakari.ailus@iki.fi