Hi Steve,

On Tue, Mar 20, 2018 at 05:37:21PM -0700, Steve Longerbeam wrote:
> Adds v4l2_async_register_fwnode_subdev(), which is a convenience function
> for parsing a sub-device's fwnode port endpoints for connected remote
> sub-devices, registering a sub-device notifier, and then registering
> the sub-device itself.
> 
> Signed-off-by: Steve Longerbeam <steve_longerb...@mentor.com>
> ---
> Changes since v2:
> - fix error-out path in v4l2_async_register_fwnode_subdev() that forgot
>   to put device.
> Changes since v1:
> - add #include <media/v4l2-subdev.h> to v4l2-fwnode.h for
>   'struct v4l2_subdev' declaration.
> ---
>  drivers/media/v4l2-core/v4l2-fwnode.c | 101 
> ++++++++++++++++++++++++++++++++++
>  include/media/v4l2-fwnode.h           |  43 +++++++++++++++
>  2 files changed, 144 insertions(+)
> 
> diff --git a/drivers/media/v4l2-core/v4l2-fwnode.c 
> b/drivers/media/v4l2-core/v4l2-fwnode.c
> index 99198b9..d42024d 100644
> --- a/drivers/media/v4l2-core/v4l2-fwnode.c
> +++ b/drivers/media/v4l2-core/v4l2-fwnode.c
> @@ -880,6 +880,107 @@ int v4l2_async_register_subdev_sensor_common(struct 
> v4l2_subdev *sd)
>  }
>  EXPORT_SYMBOL_GPL(v4l2_async_register_subdev_sensor_common);
>  
> +int v4l2_async_register_fwnode_subdev(
> +     struct v4l2_subdev *sd, size_t asd_struct_size,
> +     unsigned int *ports, unsigned int num_ports,
> +     int (*parse_endpoint)(struct device *dev,
> +                           struct v4l2_fwnode_endpoint *vep,
> +                           struct v4l2_async_subdev *asd))
> +{
> +     struct v4l2_async_notifier *notifier;
> +     struct device *dev = sd->dev;
> +     struct fwnode_handle *fwnode;
> +     unsigned int subdev_port;
> +     bool is_port;
> +     int ret;
> +
> +     if (WARN_ON(!dev))
> +             return -ENODEV;
> +
> +     fwnode = dev_fwnode(dev);
> +     if (!fwnode_device_is_available(fwnode))
> +             return -ENODEV;
> +
> +     is_port = (is_of_node(fwnode) &&
> +                of_node_cmp(to_of_node(fwnode)->name, "port") == 0);

What's the intent of this and the code below? You may not parse the graph
data structure here, it should be done in the actual firmware
implementation instead.

Also, sub-devices generally do not match ports. How sub-devices generally
correspond to fwnodes is up to the device.

> +
> +     /*
> +      * If the sub-device is a port, only parse fwnode endpoints from
> +      * this sub-device's single port id.
> +      */
> +     if (is_port) {
> +             /* verify the caller did not provide a ports array */
> +             if (ports)
> +                     return -EINVAL;
> +
> +             ret = fwnode_property_read_u32(fwnode, "reg", &subdev_port);
> +             if (ret < 0)
> +                     return ret;
> +
> +             /*
> +              * the device given to the fwnode endpoint parsing
> +              * must be the port sub-device's parent.
> +              */
> +             dev = get_device(sd->dev->parent);
> +
> +             if (WARN_ON(!dev))
> +                     return -ENODEV;
> +
> +             ports = &subdev_port;
> +             num_ports = 1;
> +     }
> +
> +     notifier = kzalloc(sizeof(*notifier), GFP_KERNEL);
> +     if (!notifier) {
> +             ret = -ENOMEM;
> +             goto out_putdev;
> +     }
> +
> +     if (!ports) {
> +             ret = v4l2_async_notifier_parse_fwnode_endpoints(
> +                     dev, notifier, asd_struct_size, parse_endpoint);
> +             if (ret < 0)
> +                     goto out_cleanup;
> +     } else {
> +             unsigned int i;
> +
> +             for (i = 0; i < num_ports; i++) {
> +                     ret = 
> v4l2_async_notifier_parse_fwnode_endpoints_by_port(
> +                             dev, notifier, asd_struct_size,
> +                             ports[i], parse_endpoint);
> +                     if (ret < 0)
> +                             goto out_cleanup;
> +             }
> +     }
> +
> +     ret = v4l2_async_subdev_notifier_register(sd, notifier);
> +     if (ret < 0)
> +             goto out_cleanup;
> +
> +     ret = v4l2_async_register_subdev(sd);
> +     if (ret < 0)
> +             goto out_unregister;
> +
> +     sd->subdev_notifier = notifier;
> +
> +     if (is_port)
> +             put_device(dev);
> +
> +     return 0;
> +
> +out_unregister:
> +     v4l2_async_notifier_unregister(notifier);
> +out_cleanup:
> +     v4l2_async_notifier_cleanup(notifier);
> +     kfree(notifier);
> +out_putdev:
> +     if (is_port)
> +             put_device(dev);
> +
> +     return ret;
> +}
> +EXPORT_SYMBOL_GPL(v4l2_async_register_fwnode_subdev);
> +
>  MODULE_LICENSE("GPL");
>  MODULE_AUTHOR("Sakari Ailus <sakari.ai...@linux.intel.com>");
>  MODULE_AUTHOR("Sylwester Nawrocki <s.nawro...@samsung.com>");
> diff --git a/include/media/v4l2-fwnode.h b/include/media/v4l2-fwnode.h
> index 9a4b3f8..4de0ac2 100644
> --- a/include/media/v4l2-fwnode.h
> +++ b/include/media/v4l2-fwnode.h
> @@ -23,6 +23,7 @@
>  #include <linux/types.h>
>  
>  #include <media/v4l2-mediabus.h>
> +#include <media/v4l2-subdev.h>
>  
>  struct fwnode_handle;
>  struct v4l2_async_notifier;
> @@ -360,4 +361,46 @@ int v4l2_async_notifier_parse_fwnode_endpoints_by_port(
>  int v4l2_async_notifier_parse_fwnode_sensor_common(
>       struct device *dev, struct v4l2_async_notifier *notifier);
>  
> +/**
> + * v4l2_async_register_fwnode_subdev - registers a sub-device to the
> + *                                   asynchronous sub-device framework
> + *                                   and parses fwnode endpoints
> + *
> + * @sd: pointer to struct &v4l2_subdev
> + * @asd_struct_size: size of the driver's async sub-device struct, including
> + *                sizeof(struct v4l2_async_subdev). The &struct
> + *                v4l2_async_subdev shall be the first member of
> + *                the driver's async sub-device struct, i.e. both
> + *                begin at the same memory address.
> + * @ports: array of port id's to parse for fwnode endpoints. If NULL, will
> + *      parse all ports owned by the sub-device.
> + * @num_ports: number of ports in @ports array. Ignored if @ports is NULL.
> + * @parse_endpoint: Driver's callback function called on each V4L2 fwnode
> + *               endpoint. Optional.
> + *
> + * This function is just like v4l2_async_register_subdev() with the exception
> + * that calling it will also parse the sub-device's firmware node endpoints
> + * using v4l2_async_notifier_parse_fwnode_endpoints() or
> + * v4l2_async_notifier_parse_fwnode_endpoints_by_port(), and registers the
> + * async sub-devices. The sub-device is similarly unregistered by calling
> + * v4l2_async_unregister_subdev().
> + *
> + * This function will work as expected if the sub-device fwnode is
> + * itself a port. The endpoints of this single port are parsed using
> + * v4l2_async_notifier_parse_fwnode_endpoints_by_port(), passing the
> + * parent of the sub-device as the port's owner. The caller must not
> + * provide a @ports array, since the sub-device owns only this port.
> + *
> + * While registered, the subdev module is marked as in-use.
> + *
> + * An error is returned if the module is no longer loaded on any attempts
> + * to register it.
> + */
> +int v4l2_async_register_fwnode_subdev(
> +     struct v4l2_subdev *sd, size_t asd_struct_size,
> +     unsigned int *ports, unsigned int num_ports,
> +     int (*parse_endpoint)(struct device *dev,
> +                           struct v4l2_fwnode_endpoint *vep,
> +                           struct v4l2_async_subdev *asd));
> +
>  #endif /* _V4L2_FWNODE_H */
> -- 
> 2.7.4
> 

-- 
Sakari Ailus
sakari.ai...@linux.intel.com

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