From 104165686ea388ddec6ec2834bf2c13873fbe91a Mon Sep 17 00:00:00 2001
From: Felipe Balbi <felipe.balbi@linux.intel.com>
Date: Wed, 7 Jun 2017 14:07:01 +0300
Subject: [PATCH] usb: gadget: udc: add a 'function' sysfs file
This file will print out the name of the currently running USB Gadget
Driver. It can be read even when there are no functions loaded.
Suggested-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
---
Documentation/ABI/stable/sysfs-class-udc | 8 ++++++++
drivers/usb/gadget/udc/core.c | 13 +++++++++++++
2 files changed, 21 insertions(+)
diff --git a/Documentation/ABI/stable/sysfs-class-udc b/Documentation/ABI/stable/sysfs-class-udc
index 85d3dac2e204c..7370deb87f87d 100644
--- a/Documentation/ABI/stable/sysfs-class-udc
+++ b/Documentation/ABI/stable/sysfs-class-udc
@@ -91,3 +91,11 @@ Description:
'configured', and 'suspended'; however not all USB Device
Controllers support reporting all states.
Users:
+
+What: /sys/class/udc/<udc>/function
+Date: June 2017
+KernelVersion: 4.13
+Contact: Felipe Balbi <balbi@kernel.org>
+Description:
+ Prints out name of currently running USB Gadget Driver.
+Users:
diff --git a/drivers/usb/gadget/udc/core.c b/drivers/usb/gadget/udc/core.c
index eec388bccb258..08facbada30e4 100644
--- a/drivers/usb/gadget/udc/core.c
+++ b/drivers/usb/gadget/udc/core.c
@@ -1460,6 +1460,18 @@ static ssize_t state_show(struct device *dev, struct device_attribute *attr,
}
static DEVICE_ATTR_RO(state);
+static ssize_t function_show(struct device *dev, struct device_attribute *attr,
+ char *buf)
+{
+ struct usb_udc *udc = container_of(dev, struct usb_udc, dev);
+ struct usb_gadget_driver *drv = udc->driver;
+
+ if (!drv || !drv->function)
+ return 0;
+ return scnprintf(buf, PAGE_SIZE, "%s\n", drv->function);
+}
+static DEVICE_ATTR_RO(function);
+
#define USB_UDC_SPEED_ATTR(name, param) \
ssize_t name##_show(struct device *dev, \
struct device_attribute *attr, char *buf) \
@@ -1495,6 +1507,7 @@ static struct attribute *usb_udc_attrs[] = {
&dev_attr_srp.attr,
&dev_attr_soft_connect.attr,
&dev_attr_state.attr,
+ &dev_attr_function.attr,
&dev_attr_current_speed.attr,
&dev_attr_maximum_speed.attr,
--
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