[RFC PATCH 1/2] USB: core: let USB device know device node

On Fri, Jan 08, 2016 at 05:50:13PM -0500, Alan Stern wrote:

On Fri, 8 Jan 2016, Peter Chen wrote:

quoted

Although most of USB devices are hot-plug's, there are still some devices
are hard wired on the board, eg, for HSIC and SSIC interface USB devices.
If these kinds of USB devices are multiple functions, and they can supply
other interfaces like i2c, gpios for other devices, we may need to
descirbe these at device tree.

In this commit, it uses "reg" in dts as port number to match the port
number decided by USB core, if they are the same, then the device node
is for the device we are creating for USB core.

Signed-off-by: Peter Chen <redacted>
---

quoted

+#include <linux/module.h>
+#include <linux/moduleparam.h>

Do you need those two #include's?

Will remove

quoted

+#include <linux/of.h>
+
+/**
+ * usb_of_find_node - Find the device node match port number
+ * @dev: the parent device node

The parameter is actually named "parent".

Sorry, I copied some code, will change.

quoted

+ * @portnum: the port number which device is connecting 
+ *
+ * Find the node from device tree according to its port number.
+ *
+ * Return: On success, a pointer to the device node, %NULL on failure.
+ */
+struct device_node *usb_of_find_node(struct device_node *parent, int portnum)
+{
+	struct device_node *node;
+	u32 port;
+
+	for_each_child_of_node(parent, node) {
+		if (!of_property_read_u32(node, "reg", &port)) {
+			if (port == portnum)
+				return node;
+		}
+	}
+
+	return NULL;
+}
+EXPORT_SYMBOL_GPL(usb_of_find_node);
+

quoted

diff --git a/include/linux/usb.h b/include/linux/usb.h
index 89533ba..a3a0b07 100644
--- a/include/linux/usb.h
+++ b/include/linux/usb.h

@@ -21,6 +21,7 @@
 #include <linux/sched.h>	/* for current && schedule_timeout */
 #include <linux/mutex.h>	/* for struct mutex */
 #include <linux/pm_runtime.h>	/* for runtime PM */
+#include <linux/of.h>		/* for device tree */

I think you don't need this line.  You can simply write:

	struct device_node;

just like the two lines below.

quoted

 struct usb_device;
 struct usb_driver;

Yes, you are right.

-- 

Best Regards,
Peter Chen