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/*
* drivers/switch/switch_class.c
*
* Copyright (C) 2008 Google, Inc.
* Author: Mike Lockwood <lockwood@android.com>
*
* This software is licensed under the terms of the GNU General Public
* License version 2, as published by the Free Software Foundation, and
* may be copied, distributed, and modified under those terms.
*
* 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.
*
*/
#include <linux/module.h>
#include <linux/types.h>
#include <linux/init.h>
#include <linux/device.h>
#include <linux/fs.h>
#include <linux/err.h>
#include <linux/switch.h>
#include <linux/hrtimer.h>
struct class *switch_class;
static atomic_t device_count;
static ssize_t state_show(struct device *dev, struct device_attribute *attr,
char *buf)
{
struct switch_dev *sdev = (struct switch_dev *)
dev_get_drvdata(dev);
if (!sdev) {
printk(KERN_ERR "switch device is NULL\n");
BUG();
return 0; /* meaningless */
}
if (sdev->print_state) {
int ret = sdev->print_state(sdev, buf);
if (ret >= 0)
return ret;
}
return sprintf(buf, "%d\n", sdev->state);
}
static ssize_t name_show(struct device *dev, struct device_attribute *attr,
char *buf)
{
struct switch_dev *sdev = (struct switch_dev *)
dev_get_drvdata(dev);
if (!sdev) {
printk(KERN_ERR "switch device is NULL\n");
BUG();
return 0; /* meaningless */
}
if (sdev->print_name) {
int ret = sdev->print_name(sdev, buf);
if (ret >= 0)
return ret;
}
return sprintf(buf, "%s\n", sdev->name);
}
static DEVICE_ATTR(state, S_IRUGO | S_IWUSR, state_show, NULL);
static DEVICE_ATTR(name, S_IRUGO | S_IWUSR, name_show, NULL);
void switch_set_state(struct switch_dev *sdev, int state)
{
char name_buf[120];
char state_buf[120];
char timestamp_buf[120];
char *prop_buf;
char *envp[4];
int env_offset = 0;
int length;
if (sdev->state != state) {
sdev->state = state;
prop_buf = (char *)get_zeroed_page(GFP_KERNEL);
if (prop_buf) {
length = name_show(sdev->dev, NULL, prop_buf);
if (length > 0) {
if (prop_buf[length - 1] == '\n')
prop_buf[length - 1] = 0;
snprintf(name_buf, sizeof(name_buf),
"SWITCH_NAME=%s", prop_buf);
envp[env_offset++] = name_buf;
}
length = state_show(sdev->dev, NULL, prop_buf);
if (length > 0) {
if (prop_buf[length - 1] == '\n')
prop_buf[length - 1] = 0;
snprintf(state_buf, sizeof(state_buf),
"SWITCH_STATE=%s", prop_buf);
envp[env_offset++] = state_buf;
}
snprintf(timestamp_buf, sizeof(timestamp_buf),
"SWITCH_TIME=%llu", ktime_to_ns(ktime_get()));
envp[env_offset++] = timestamp_buf;
envp[env_offset] = NULL;
kobject_uevent_env(&sdev->dev->kobj, KOBJ_CHANGE, envp);
free_page((unsigned long)prop_buf);
} else {
printk(KERN_ERR "out of memory in switch_set_state\n");
kobject_uevent(&sdev->dev->kobj, KOBJ_CHANGE);
}
}
}
EXPORT_SYMBOL_GPL(switch_set_state);
static int create_switch_class(void)
{
if (!switch_class) {
switch_class = class_create(THIS_MODULE, "switch");
if (IS_ERR(switch_class))
return PTR_ERR(switch_class);
atomic_set(&device_count, 0);
}
return 0;
}
int switch_dev_register(struct switch_dev *sdev)
{
int ret;
if (!switch_class) {
ret = create_switch_class();
if (ret < 0)
return ret;
}
sdev->index = atomic_inc_return(&device_count);
sdev->dev = device_create(switch_class, NULL,
MKDEV(0, sdev->index), NULL, sdev->name);
if (IS_ERR(sdev->dev))
return PTR_ERR(sdev->dev);
ret = device_create_file(sdev->dev, &dev_attr_state);
if (ret < 0)
goto err_create_file_1;
ret = device_create_file(sdev->dev, &dev_attr_name);
if (ret < 0)
goto err_create_file_2;
dev_set_drvdata(sdev->dev, sdev);
sdev->state = 0;
return 0;
err_create_file_2:
device_remove_file(sdev->dev, &dev_attr_state);
err_create_file_1:
device_destroy(switch_class, MKDEV(0, sdev->index));
printk(KERN_ERR "switch: Failed to register driver %s\n", sdev->name);
return ret;
}
EXPORT_SYMBOL_GPL(switch_dev_register);
void switch_dev_unregister(struct switch_dev *sdev)
{
device_remove_file(sdev->dev, &dev_attr_name);
device_remove_file(sdev->dev, &dev_attr_state);
device_destroy(switch_class, MKDEV(0, sdev->index));
dev_set_drvdata(sdev->dev, NULL);
}
EXPORT_SYMBOL_GPL(switch_dev_unregister);
static int __init switch_class_init(void)
{
return create_switch_class();
}
static void __exit switch_class_exit(void)
{
class_destroy(switch_class);
}
module_init(switch_class_init);
module_exit(switch_class_exit);
MODULE_AUTHOR("Mike Lockwood <lockwood@android.com>");
MODULE_DESCRIPTION("Switch class driver");
MODULE_LICENSE("GPL");
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