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android_kernel_xiaomi_sm8350/drivers/usb/misc/phidgetservo.c
Greg Kroah-Hartman bfd3a5a96c USB: Phidget: fix race in device_create 
There is a race from when a device is created with device_create() and
then the drvdata is set with a call to dev_set_drvdata() in which a
sysfs file could be open, yet the drvdata will be NULL, causing all
sorts of bad things to happen.

This patch fixes the problem by using the new function,
device_create_drvdata().  It fixes all 3 phidget drivers, which all have
the same problem.

Cc: Kay Sievers <kay.sievers@vrfy.org>
Cc: Sean Young <sean@mess.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2008-05-20 13:31:56 -07:00

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/*
* USB PhidgetServo driver 1.0
*
* Copyright (C) 2004, 2006 Sean Young <sean@mess.org>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This is a driver for the USB PhidgetServo version 2.0 and 3.0 servo
* controllers available at: http://www.phidgets.com/
*
* Note that the driver takes input as: degrees.minutes
*
* CAUTION: Generally you should use 0 < degrees < 180 as anything else
* is probably beyond the range of your servo and may damage it.
*/
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/usb.h>
#include "phidget.h"
#define DRIVER_AUTHOR "Sean Young <sean@mess.org>"
#define DRIVER_DESC "USB PhidgetServo Driver"
#define VENDOR_ID_GLAB 0x06c2
#define DEVICE_ID_GLAB_PHIDGETSERVO_QUAD 0x0038
#define DEVICE_ID_GLAB_PHIDGETSERVO_UNI 0x0039
#define VENDOR_ID_WISEGROUP 0x0925
#define VENDOR_ID_WISEGROUP_PHIDGETSERVO_QUAD 0x8101
#define VENDOR_ID_WISEGROUP_PHIDGETSERVO_UNI 0x8104
#define SERVO_VERSION_30 0x01
#define SERVO_COUNT_QUAD 0x02
static struct usb_device_id id_table[] = {
{
USB_DEVICE(VENDOR_ID_GLAB, DEVICE_ID_GLAB_PHIDGETSERVO_QUAD),
.driver_info = SERVO_VERSION_30 | SERVO_COUNT_QUAD
},
{
USB_DEVICE(VENDOR_ID_GLAB, DEVICE_ID_GLAB_PHIDGETSERVO_UNI),
.driver_info = SERVO_VERSION_30
},
{
USB_DEVICE(VENDOR_ID_WISEGROUP,
VENDOR_ID_WISEGROUP_PHIDGETSERVO_QUAD),
.driver_info = SERVO_COUNT_QUAD
},
{
USB_DEVICE(VENDOR_ID_WISEGROUP,
VENDOR_ID_WISEGROUP_PHIDGETSERVO_UNI),
.driver_info = 0
},
{}
};
MODULE_DEVICE_TABLE(usb, id_table);
static int unsigned long device_no;
struct phidget_servo {
struct usb_device *udev;
struct device *dev;
int dev_no;
ulong type;
int pulse[4];
int degrees[4];
int minutes[4];
};
static int
change_position_v30(struct phidget_servo *servo, int servo_no, int degrees,
int minutes)
{
int retval;
unsigned char *buffer;
if (degrees < -23 || degrees > 362)
return -EINVAL;
buffer = kmalloc(6, GFP_KERNEL);
if (!buffer) {
dev_err(&servo->udev->dev, "%s - out of memory\n",
__func__);
return -ENOMEM;
}
/*
* pulse = 0 - 4095
* angle = 0 - 180 degrees
*
* pulse = angle * 10.6 + 243.8
*/
servo->pulse[servo_no] = ((degrees*60 + minutes)*106 + 2438*60)/600;
servo->degrees[servo_no]= degrees;
servo->minutes[servo_no]= minutes;
/*
* The PhidgetServo v3.0 is controlled by sending 6 bytes,
* 4 * 12 bits for each servo.
*
* low = lower 8 bits pulse
* high = higher 4 bits pulse
*
* offset bits
* +---+-----------------+
* | 0 | low 0 |
* +---+--------+--------+
* | 1 | high 1 | high 0 |
* +---+--------+--------+
* | 2 | low 1 |
* +---+-----------------+
* | 3 | low 2 |
* +---+--------+--------+
* | 4 | high 3 | high 2 |
* +---+--------+--------+
* | 5 | low 3 |
* +---+-----------------+
*/
buffer[0] = servo->pulse[0] & 0xff;
buffer[1] = (servo->pulse[0] >> 8 & 0x0f)
| (servo->pulse[1] >> 4 & 0xf0);
buffer[2] = servo->pulse[1] & 0xff;
buffer[3] = servo->pulse[2] & 0xff;
buffer[4] = (servo->pulse[2] >> 8 & 0x0f)
| (servo->pulse[3] >> 4 & 0xf0);
buffer[5] = servo->pulse[3] & 0xff;
dev_dbg(&servo->udev->dev,
"data: %02x %02x %02x %02x %02x %02x\n",
buffer[0], buffer[1], buffer[2],
buffer[3], buffer[4], buffer[5]);
retval = usb_control_msg(servo->udev,
usb_sndctrlpipe(servo->udev, 0),
0x09, 0x21, 0x0200, 0x0000, buffer, 6, 2000);
kfree(buffer);
return retval;
}
static int
change_position_v20(struct phidget_servo *servo, int servo_no, int degrees,
int minutes)
{
int retval;
unsigned char *buffer;
if (degrees < -23 || degrees > 278)
return -EINVAL;
buffer = kmalloc(2, GFP_KERNEL);
if (!buffer) {
dev_err(&servo->udev->dev, "%s - out of memory\n",
__func__);
return -ENOMEM;
}
/*
* angle = 0 - 180 degrees
* pulse = angle + 23
*/
servo->pulse[servo_no]= degrees + 23;
servo->degrees[servo_no]= degrees;
servo->minutes[servo_no]= 0;
/*
* The PhidgetServo v2.0 is controlled by sending two bytes. The
* first byte is the servo number xor'ed with 2:
*
* servo 0 = 2
* servo 1 = 3
* servo 2 = 0
* servo 3 = 1
*
* The second byte is the position.
*/
buffer[0] = servo_no ^ 2;
buffer[1] = servo->pulse[servo_no];
dev_dbg(&servo->udev->dev, "data: %02x %02x\n", buffer[0], buffer[1]);
retval = usb_control_msg(servo->udev,
usb_sndctrlpipe(servo->udev, 0),
0x09, 0x21, 0x0200, 0x0000, buffer, 2, 2000);
kfree(buffer);
return retval;
}
#define show_set(value) \
static ssize_t set_servo##value (struct device *dev, \
struct device_attribute *attr, \
const char *buf, size_t count) \
{ \
int degrees, minutes, retval; \
struct phidget_servo *servo = dev_get_drvdata(dev); \
\
minutes = 0; \
/* must at least convert degrees */ \
if (sscanf(buf, "%d.%d", &degrees, &minutes) < 1) { \
return -EINVAL; \
} \
\
if (minutes < 0 || minutes > 59) \
return -EINVAL; \
\
if (servo->type & SERVO_VERSION_30) \
retval = change_position_v30(servo, value, degrees, \
minutes); \
else \
retval = change_position_v20(servo, value, degrees, \
minutes); \
\
return retval < 0 ? retval : count; \
} \
\
static ssize_t show_servo##value (struct device *dev, \
struct device_attribute *attr, \
char *buf) \
{ \
struct phidget_servo *servo = dev_get_drvdata(dev); \
\
return sprintf(buf, "%d.%02d\n", servo->degrees[value], \
servo->minutes[value]); \
}
#define servo_attr(value) \
__ATTR(servo##value, S_IWUGO | S_IRUGO, \
show_servo##value, set_servo##value)
show_set(0);
show_set(1);
show_set(2);
show_set(3);
static struct device_attribute dev_attrs[] = {
servo_attr(0), servo_attr(1), servo_attr(2), servo_attr(3)
};
static int
servo_probe(struct usb_interface *interface, const struct usb_device_id *id)
{
struct usb_device *udev = interface_to_usbdev(interface);
struct phidget_servo *dev;
int bit, value, rc;
int servo_count, i;
dev = kzalloc(sizeof (struct phidget_servo), GFP_KERNEL);
if (dev == NULL) {
dev_err(&interface->dev, "%s - out of memory\n", __func__);
rc = -ENOMEM;
goto out;
}
dev->udev = usb_get_dev(udev);
dev->type = id->driver_info;
dev->dev_no = -1;
usb_set_intfdata(interface, dev);
do {
bit = find_first_zero_bit(&device_no, sizeof(device_no));
value = test_and_set_bit(bit, &device_no);
} while (value);
dev->dev_no = bit;
dev->dev = device_create_drvdata(phidget_class, &dev->udev->dev,
MKDEV(0, 0), dev,
"servo%d", dev->dev_no);
if (IS_ERR(dev->dev)) {
rc = PTR_ERR(dev->dev);
dev->dev = NULL;
goto out;
}
servo_count = dev->type & SERVO_COUNT_QUAD ? 4 : 1;
for (i=0; i<servo_count; i++) {
rc = device_create_file(dev->dev, &dev_attrs[i]);
if (rc)
goto out2;
}
dev_info(&interface->dev, "USB %d-Motor PhidgetServo v%d.0 attached\n",
servo_count, dev->type & SERVO_VERSION_30 ? 3 : 2);
if (!(dev->type & SERVO_VERSION_30))
dev_info(&interface->dev,
"WARNING: v2.0 not tested! Please report if it works.\n");
return 0;
out2:
while (i-- > 0)
device_remove_file(dev->dev, &dev_attrs[i]);
out:
if (dev) {
if (dev->dev)
device_unregister(dev->dev);
if (dev->dev_no >= 0)
clear_bit(dev->dev_no, &device_no);
kfree(dev);
}
return rc;
}
static void
servo_disconnect(struct usb_interface *interface)
{
struct phidget_servo *dev;
int servo_count, i;
dev = usb_get_intfdata(interface);
usb_set_intfdata(interface, NULL);
if (!dev)
return;
servo_count = dev->type & SERVO_COUNT_QUAD ? 4 : 1;
for (i=0; i<servo_count; i++)
device_remove_file(dev->dev, &dev_attrs[i]);
device_unregister(dev->dev);
usb_put_dev(dev->udev);
dev_info(&interface->dev, "USB %d-Motor PhidgetServo v%d.0 detached\n",
servo_count, dev->type & SERVO_VERSION_30 ? 3 : 2);
clear_bit(dev->dev_no, &device_no);
kfree(dev);
}
static struct usb_driver servo_driver = {
.name = "phidgetservo",
.probe = servo_probe,
.disconnect = servo_disconnect,
.id_table = id_table
};
static int __init
phidget_servo_init(void)
{
int retval;
retval = usb_register(&servo_driver);
if (retval)
err("usb_register failed. Error number %d", retval);
return retval;
}
static void __exit
phidget_servo_exit(void)
{
usb_deregister(&servo_driver);
}
module_init(phidget_servo_init);
module_exit(phidget_servo_exit);
MODULE_AUTHOR(DRIVER_AUTHOR);
MODULE_DESCRIPTION(DRIVER_DESC);
MODULE_LICENSE("GPL");
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