[PATCH] USB: core: let USB device know device node

Paolo Pisati paolo.pisati at canonical.com
Thu Oct 18 13:24:14 UTC 2018


From: Peter Chen <peter.chen at freescale.com>

BugLink: http://bugs.launchpad.net/bugs/1798578

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
describe these at device tree.

In this commit, it uses "reg" in dts as physical port number to match
the phyiscal 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 <peter.chen at freescale.com>
Acked-by: Philipp Zabel <p.zabel at pengutronix.de>
Acked-by: Alan Stern <stern at rowland.harvard.edu>
Acked-by: Rob Herring <robh at kernel.org>
Acked-by: Arnd Bergmann <arnd at arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
(cherry picked from commit 69bec725985324e79b1c47ea287815ac4ddb0521)
Signed-off-by: Paolo Pisati <paolo.pisati at canonical.com>
---
 .../devicetree/bindings/usb/usb-device.txt         | 28 +++++++++++++
 drivers/usb/core/Makefile                          |  2 +-
 drivers/usb/core/of.c                              | 47 ++++++++++++++++++++++
 drivers/usb/core/usb.c                             | 10 +++++
 include/linux/usb/of.h                             |  7 ++++
 5 files changed, 93 insertions(+), 1 deletion(-)
 create mode 100644 Documentation/devicetree/bindings/usb/usb-device.txt
 create mode 100644 drivers/usb/core/of.c

diff --git a/Documentation/devicetree/bindings/usb/usb-device.txt b/Documentation/devicetree/bindings/usb/usb-device.txt
new file mode 100644
index 0000000..1c35e7b
--- /dev/null
+++ b/Documentation/devicetree/bindings/usb/usb-device.txt
@@ -0,0 +1,28 @@
+Generic USB Device Properties
+
+Usually, we only use device tree for hard wired USB device.
+The reference binding doc is from:
+http://www.firmware.org/1275/bindings/usb/usb-1_0.ps
+
+Required properties:
+- compatible: usbVID,PID. The textual representation of VID, PID shall
+  be in lower case hexadecimal with leading zeroes suppressed. The
+  other compatible strings from the above standard binding could also
+  be used, but a device adhering to this binding may leave out all except
+  for usbVID,PID.
+- reg: the port number which this device is connecting to, the range
+  is 1-31.
+
+Example:
+
+&usb1 {
+	status = "okay";
+
+	#address-cells = <1>;
+	#size-cells = <0>;
+
+	hub: genesys at 1 {
+		compatible = "usb5e3,608";
+		reg = <1>;
+	};
+}
diff --git a/drivers/usb/core/Makefile b/drivers/usb/core/Makefile
index 2f6f932..9780877 100644
--- a/drivers/usb/core/Makefile
+++ b/drivers/usb/core/Makefile
@@ -5,7 +5,7 @@
 usbcore-y := usb.o hub.o hcd.o urb.o message.o driver.o
 usbcore-y += config.o file.o buffer.o sysfs.o endpoint.o
 usbcore-y += devio.o notify.o generic.o quirks.o devices.o
-usbcore-y += port.o
+usbcore-y += port.o of.o
 
 usbcore-$(CONFIG_PCI)		+= hcd-pci.o
 usbcore-$(CONFIG_ACPI)		+= usb-acpi.o
diff --git a/drivers/usb/core/of.c b/drivers/usb/core/of.c
new file mode 100644
index 0000000..2289700
--- /dev/null
+++ b/drivers/usb/core/of.c
@@ -0,0 +1,47 @@
+/*
+ * of.c		The helpers for hcd device tree support
+ *
+ * Copyright (C) 2016 Freescale Semiconductor, Inc.
+ * Author: Peter Chen <peter.chen at freescale.com>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2  of
+ * the License as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <linux/of.h>
+
+/**
+ * usb_of_get_child_node - Find the device node match port number
+ * @parent: the parent device node
+ * @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_get_child_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_get_child_node);
+
diff --git a/drivers/usb/core/usb.c b/drivers/usb/core/usb.c
index f8bbd0b..3fdb2f8 100644
--- a/drivers/usb/core/usb.c
+++ b/drivers/usb/core/usb.c
@@ -36,6 +36,7 @@
 #include <linux/mutex.h>
 #include <linux/workqueue.h>
 #include <linux/debugfs.h>
+#include <linux/usb/of.h>
 
 #include <asm/io.h>
 #include <linux/scatterlist.h>
@@ -469,6 +470,7 @@ struct usb_device *usb_alloc_dev(struct usb_device *parent,
 		dev->route = 0;
 
 		dev->dev.parent = bus->controller;
+		dev->dev.of_node = bus->controller->of_node;
 		dev_set_name(&dev->dev, "usb%d", bus->busnum);
 		root_hub = 1;
 	} else {
@@ -493,6 +495,14 @@ struct usb_device *usb_alloc_dev(struct usb_device *parent,
 		dev->dev.parent = &parent->dev;
 		dev_set_name(&dev->dev, "%d-%s", bus->busnum, dev->devpath);
 
+		if (!parent->parent) {
+			/* device under root hub's port */
+			port1 = usb_hcd_find_raw_port_number(usb_hcd,
+				port1);
+		}
+		dev->dev.of_node = usb_of_get_child_node(parent->dev.of_node,
+				port1);
+
 		/* hub driver sets up TT records */
 	}
 
diff --git a/include/linux/usb/of.h b/include/linux/usb/of.h
index c3fe9e4..bc7644b 100644
--- a/include/linux/usb/of.h
+++ b/include/linux/usb/of.h
@@ -15,6 +15,8 @@
 bool of_usb_host_tpl_support(struct device_node *np);
 int of_usb_update_otg_caps(struct device_node *np,
 			struct usb_otg_caps *otg_caps);
+struct device_node *usb_of_get_child_node(struct device_node *parent,
+			int portnum);
 #else
 static inline bool of_usb_host_tpl_support(struct device_node *np)
 {
@@ -25,6 +27,11 @@ static inline int of_usb_update_otg_caps(struct device_node *np,
 {
 	return 0;
 }
+static inline struct device_node *usb_of_get_child_node
+		(struct device_node *parent, int portnum)
+{
+	return NULL;
+}
 #endif
 
 #if IS_ENABLED(CONFIG_OF) && IS_ENABLED(CONFIG_USB_SUPPORT)
-- 
2.7.4





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