/*
* drivers/extcon/extcon_class.c
*
* External connector (extcon) class driver
*
* Copyright (C) 2012 Samsung Electronics
* Author: Donggeun Kim <dg77.kim@samsung.com>
* Author: MyungJoo Ham <myungjoo.ham@samsung.com>
*
* based on android/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/extcon.h>
#include <linux/slab.h>
struct class *extcon_class;
#if defined(CONFIG_ANDROID) && !defined(CONFIG_ANDROID_SWITCH)
static struct class_compat *switch_class;
#endif /* CONFIG_ANDROID && !defined(CONFIG_ANDROID_SWITCH) */
static LIST_HEAD(extcon_dev_list);
static DEFINE_MUTEX(extcon_dev_list_lock);
static ssize_t state_show(struct device *dev, struct device_attribute *attr,
char *buf)
{
struct extcon_dev *edev = (struct extcon_dev *) dev_get_drvdata(dev);
if (edev->print_state) {
int ret = edev->print_state(edev, buf);
if (ret >= 0)
return ret;
/* Use default if failed */
}
return sprintf(buf, "%u\n", edev->state);
}
static ssize_t name_show(struct device *dev, struct device_attribute *attr,
char *buf)
{
struct extcon_dev *edev = (struct extcon_dev *) dev_get_drvdata(dev);
/* Optional callback given by the user */
if (edev->print_name) {
int ret = edev->print_name(edev, buf);
if (ret >= 0)
return ret;
}
return sprintf(buf, "%s\n", dev_name(edev->dev));
}
/**
* extcon_set_state() - Set the cable attach states of the extcon device.
* @edev: the extcon device
* @state: new cable attach status for @edev
*
* Changing the state sends uevent with environment variable containing
* the name of extcon device (envp[0]) and the state output (envp[1]).
* Tizen uses this format for extcon device to get events from ports.
* Android uses this format as well.
*
* Note that notifier provides the which bits are changes in the state
* variable with "val" to the callback.
*/
void extcon_set_state(struct extcon_dev *edev, u32 state)
{
char name_buf[120];
char state_buf[120];
char *prop_buf;
char *envp[3];
int env_offset = 0;
int length;
u32 old_state = edev->state;
if (edev->state != state) {
edev->state = state;
raw_notifier_call_chain(&edev->nh, old_state ^ edev->state,
edev);
prop_buf = (char *)get_zeroed_page(GFP_KERNEL);
if (prop_buf) {
length = name_show(edev->dev, NULL, prop_buf);
if (length > 0) {
if (prop_buf[length - 1] == '\n')
prop_buf[length - 1] = 0;
snprintf(name_buf, sizeof(name_buf),
"NAME=%s", prop_buf);
envp[env_offset++] = name_buf;
}
length = state_show(edev->dev, NULL, prop_buf);
if (length > 0) {
if (prop_buf[length - 1] == '\n')
prop_buf[length - 1] = 0;
snprintf(state_buf, sizeof(state_buf),
"STATE=%s", prop_buf);
envp[env_offset++] = state_buf;
}
envp[env_offset] = NULL;
kobject_uevent_env(&edev->dev->kobj, KOBJ_CHANGE, envp);
free_page((unsigned long)prop_buf);
} else {
dev_err(edev->dev, "out of memory in extcon_set_state\n");
kobject_uevent(&edev->dev->kobj, KOBJ_CHANGE);
}
}
}
EXPORT_SYMBOL_GPL(extcon_set_state);
/**
* extcon_get_extcon_dev() - Get the extcon device instance from the name
* @extcon_name: The extcon name provided with extcon_dev_register()
*/
struct extcon_dev *extcon_get_extcon_dev(const char *extcon_name)
{
struct extcon_dev *sd;
mutex_lock(&extcon_dev_list_lock);
list_for_each_entry(sd, &extcon_dev_list, entry) {
if (!strcmp(sd->name, extcon_name))
goto out;
}
sd = NULL;
out:
mutex_unlock(&extcon_dev_list_lock);
return sd;
}
EXPORT_SYMBOL_GPL(extcon_get_extcon_dev);
/**
* extcon_register_notifier() - Register a notifee to get notified by
* any attach status changes from the extcon.
* @edev: the extcon device.
* @nb: a notifier block to be registered.
*/
int extcon_register_notifier(struct extcon_dev *edev,
struct notifier_block *nb)
{
return raw_notifier_chain_register(&edev->nh, nb);
}
EXPORT_SYMBOL_GPL(extcon_register_notifier);
/**
* extcon_unregister_notifier() - Unregister a notifee from the extcon device.
* @edev: the extcon device.
* @nb: a registered notifier block to be unregistered.
*/
int extcon_unregister_notifier(struct extcon_dev *edev,
struct notifier_block *nb)
{
return raw_notifier_chain_unregister(&edev->nh, nb);
}
EXPORT_SYMBOL_GPL(extcon_unregister_notifier);
static struct device_attribute extcon_attrs[] = {
__ATTR_RO(state),
__ATTR_RO(name),
};
static int create_extcon_class(void)
{
if (!extcon_class) {
extcon_class = class_create(THIS_MODULE, "extcon");
if (IS_ERR(extcon_class))
return PTR_ERR(extcon_class);
extcon_class->dev_attrs = extcon_attrs;
#if defined(CONFIG_ANDROID) && !defined(CONFIG_ANDROID_SWITCH)
switch_class = class_compat_register("switch");
if (WARN(!switch_class, "cannot allocate"))
return -ENOMEM;
#endif /* CONFIG_ANDROID && !defined(CONFIG_ANDROID_SWITCH) */
}
return 0;
}
static void extcon_cleanup(struct extcon_dev *edev, bool skip)
{
mutex_lock(&extcon_dev_list_lock);
list_del(&edev->entry);
mutex_unlock(&extcon_dev_list_lock);
if (!skip && get_device(edev->dev)) {
device_unregister(edev->dev);
put_device(edev->dev);
}
kfree(edev->dev);
}
static void extcon_dev_release(struct device *dev)
{
struct extcon_dev *edev = (struct extcon_dev *) dev_get_drvdata(dev);
extcon_cleanup(edev, true);
}
/**
* extcon_dev_register() - Register a new extcon device
* @edev : the new extcon device (should be allocated before calling)
* @dev : the parent device for this extcon device.
*
* Among the members of edev struct, please set the "user initializing data"
* in any case and set the "optional callbacks" if required. However, please
* do not set the values of "internal data", which are initialized by
* this function.
*/
int extcon_dev_register(struct extcon_dev *edev, struct device *dev)
{
int ret;
if (!extcon_class) {
ret = create_extcon_class();
if (ret < 0)
return ret;
}
edev->dev = kzalloc(sizeof(struct device), GFP_KERNEL);
edev->dev->parent = dev;
edev->dev->class = extcon_class;
edev->dev->release = extcon_dev_release;
dev_set_name(edev->dev, edev->name ? edev->name : dev_name(dev));
ret = device_register(edev->dev);
if (ret) {
put_device(edev->dev);
goto err_dev;
}
#if defined(CONFIG_ANDROID) && !defined(CONFIG_ANDROID_SWITCH)
if (switch_class)
ret = class_compat_create_link(switch_class, edev->dev,
dev);
#endif /* CONFIG_ANDROID && !defined(CONFIG_ANDROID_SWITCH) */
RAW_INIT_NOTIFIER_HEAD(&edev->nh);
dev_set_drvdata(edev->dev, edev);
edev->state = 0;
mutex_lock(&extcon_dev_list_lock);
list_add(&edev->entry, &extcon_dev_list);
mutex_unlock(&extcon_dev_list_lock);
return 0;
err_dev:
kfree(edev->dev);
return ret;
}
EXPORT_SYMBOL_GPL(extcon_dev_register);
/**
* extcon_dev_unregister() - Unregister the extcon device.
* @edev: the extcon device instance to be unregitered.
*
* Note that this does not call kfree(edev) because edev was not allocated
* by this class.
*/
void extcon_dev_unregister(struct extcon_dev *edev)
{
extcon_cleanup(edev, false);
}
EXPORT_SYMBOL_GPL(extcon_dev_unregister);
static int __init extcon_class_init(void)
{
return create_extcon_class();
}
module_init(extcon_class_init);
static void __exit extcon_class_exit(void)
{
class_destroy(extcon_class);
}
module_exit(extcon_class_exit);
MODULE_AUTHOR("Mike Lockwood <lockwood@android.com>");
MODULE_AUTHOR("Donggeun Kim <dg77.kim@samsung.com>");
MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@samsung.com>");
MODULE_DESCRIPTION("External connector (extcon) class driver");
MODULE_LICENSE("GPL");
