Re: [PATCH v13 17/25] v4l: fwnode: Add a helper function for parsing generic references

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

Hi Sakari,

Thank you for the patch.

On Friday, 15 September 2017 17:17:16 EEST Sakari Ailus wrote:
> Add function v4l2_fwnode_reference_parse() for parsing them as async
> sub-devices. This can be done on e.g. flash or lens async sub-devices that
> are not part of but are associated with a sensor.
> 
> Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
> ---
>  drivers/media/v4l2-core/v4l2-fwnode.c | 69 ++++++++++++++++++++++++++++++++
>  1 file changed, 69 insertions(+)
> 
> diff --git a/drivers/media/v4l2-core/v4l2-fwnode.c
> b/drivers/media/v4l2-core/v4l2-fwnode.c index 44ee35f6aad5..65e84ea1cc35
> 100644
> --- a/drivers/media/v4l2-core/v4l2-fwnode.c
> +++ b/drivers/media/v4l2-core/v4l2-fwnode.c
> @@ -498,6 +498,75 @@ int v4l2_async_notifier_parse_fwnode_endpoints_by_port(
> }
>  EXPORT_SYMBOL_GPL(v4l2_async_notifier_parse_fwnode_endpoints_by_port);
> 
> +/*
> + * v4l2_fwnode_reference_parse - parse references for async sub-devices
> + * @dev: the device node the properties of which are parsed for references
> + * @notifier: the async notifier where the async subdevs will be added
> + * @prop: the name of the property
> + *
> + * Return: 0 on success
> + *	   -ENOENT if no entries were found
> + *	   -ENOMEM if memory allocation failed
> + *	   -EINVAL if property parsing failed
> + */
> +static int v4l2_fwnode_reference_parse(
> +	struct device *dev, struct v4l2_async_notifier *notifier,
> +	const char *prop)
> +{
> +	struct fwnode_reference_args args;
> +	unsigned int index;
> +	int ret;
> +
> +	for (index = 0;
> +	     !(ret = fwnode_property_get_reference_args(
> +		       dev_fwnode(dev), prop, NULL, 0, index, &args));
> +	     index++)
> +		fwnode_handle_put(args.fwnode);

This seems to indicate that the fwnode API is missing a function to count the 
number of references in a property. Should that be fixed ?

The rest looks OK to me.

> +	if (!index)
> +		return -ENOENT;
> +
> +	/*
> +	 * Note that right now both -ENODATA and -ENOENT may signal
> +	 * out-of-bounds access. Return the error in cases other than that.
> +	 */
> +	if (ret != -ENOENT && ret != -ENODATA)
> +		return ret;
> +
> +	ret = v4l2_async_notifier_realloc(notifier,
> +					  notifier->num_subdevs + index);
> +	if (ret)
> +		return ret;
> +
> +	for (index = 0; !fwnode_property_get_reference_args(
> +		     dev_fwnode(dev), prop, NULL, 0, index, &args);
> +	     index++) {
> +		struct v4l2_async_subdev *asd;
> +
> +		if (WARN_ON(notifier->num_subdevs >= notifier->max_subdevs)) {
> +			ret = -EINVAL;
> +			goto error;
> +		}
> +
> +		asd = kzalloc(sizeof(*asd), GFP_KERNEL);
> +		if (!asd) {
> +			ret = -ENOMEM;
> +			goto error;
> +		}
> +
> +		notifier->subdevs[notifier->num_subdevs] = asd;
> +		asd->match.fwnode.fwnode = args.fwnode;
> +		asd->match_type = V4L2_ASYNC_MATCH_FWNODE;
> +		notifier->num_subdevs++;
> +	}
> +
> +	return 0;
> +
> +error:
> +	fwnode_handle_put(args.fwnode);
> +	return ret;
> +}
> +
>  MODULE_LICENSE("GPL");
>  MODULE_AUTHOR("Sakari Ailus <sakari.ailus@linux.intel.com>");
>  MODULE_AUTHOR("Sylwester Nawrocki <s.nawrocki@samsung.com>");


-- 
Regards,

Laurent Pinchart