rpmsg: smd: Register rpmsg user space interface for edges

Create and register a rpmsg device for use with the rpmsg user space
interface, allowing user space to access SMD channels.

Also provide the "rpmsg_name" device attribute to expose the edge name
in sysfs, allowing the user to write udev rules for specific rpmsg
devices and their children.

Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>

drivers/rpmsg/qcom_smd.c

@@ -1002,6 +1002,20 @@ static int qcom_smd_create_device(struct qcom_smd_channel *channel)
 	return rpmsg_register_device(rpdev);
 }
 
+static int qcom_smd_create_chrdev(struct qcom_smd_edge *edge)
+{
+	struct qcom_smd_device *qsdev;
+
+	qsdev = kzalloc(sizeof(*qsdev), GFP_KERNEL);
+	if (!qsdev)
+		return -ENOMEM;
+
+	qsdev->edge = edge;
+	qsdev->rpdev.ops = &qcom_smd_device_ops;
+	qsdev->rpdev.dev.parent = &edge->dev;
+	return rpmsg_chrdev_register_device(&qsdev->rpdev);
+}
+
 /*
  * Allocate the qcom_smd_channel object for a newly found smd channel,
  * retrieving and validating the smem items involved.
@@ -1357,6 +1371,12 @@ struct qcom_smd_edge *qcom_smd_register_edge(struct device *parent,
 		goto unregister_dev;
 	}
 
+	ret = qcom_smd_create_chrdev(edge);
+	if (ret) {
+		dev_err(&edge->dev, "failed to register chrdev for edge\n");
+		goto unregister_dev;
+	}
+
 	schedule_work(&edge->scan_work);
 
 	return edge;