Commit de55d871 authored by MyungJoo Ham's avatar MyungJoo Ham Committed by Greg Kroah-Hartman

Extcon (external connector): import Android's switch class and modify.

External connector class (extcon) is based on and an extension of
Android kernel's switch class located at linux/drivers/switch/.

This patch provides the before-extension switch class moved to the
location where the extcon will be located (linux/drivers/extcon/) and
updates to handle class properly.

The before-extension class, switch class of Android kernel, commits
imported are:

switch: switch class and GPIO drivers. (splitted)
Author: Mike Lockwood <lockwood@android.com>

switch: Use device_create instead of device_create_drvdata.
Author: Arve Hjønnevåg <arve@android.com>

In this patch, upon the commits of Android kernel, we have added:
- Relocated and renamed for extcon.
- Comments, module name, and author information are updated
- Code clean for successing patches
- Bugfix: enabling write access without write functions
- Class/device/sysfs create/remove handling
- Added comments about uevents
- Format changes for extcon_dev_register() to have a parent dev.
Signed-off-by: default avatarMyungJoo Ham <myungjoo.ham@samsung.com>
Signed-off-by: default avatarKyungmin Park <kyungmin.park@samsung.com>
Reviewed-by: default avatarMark Brown <broonie@opensource.wolfsonmicro.com>

--
Changes from v7
- Compiler error fixed when it is compiled as a module.
- Removed out-of-date Kconfig entry

Changes from v6
- Updated comment/strings
- Revised "Android-compatible" mode.
   * Automatically activated if CONFIG_ANDROID && !CONFIG_ANDROID_SWITCH
   * Creates /sys/class/switch/*, which is a copy of /sys/class/extcon/*

Changes from v5
- Split the patch
- Style fixes
- "Android-compatible" mode is enabled by Kconfig option.

Changes from v2
- Updated name_show
- Sysfs entries are handled by class itself.
- Updated the method to add/remove devices for the class
- Comments on uevent send
- Able to become a module
- Compatible with Android platform

Changes from RFC
- Renamed to extcon (external connector) from multistate switch
- Added a seperated directory (drivers/extcon)
- Added kerneldoc comments
- Removed unused variables from extcon_gpio.c
- Added ABI Documentation.
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 7cd9c9bb
What: /sys/class/extcon/.../
Date: December 2011
Contact: MyungJoo Ham <myungjoo.ham@samsung.com>
Description:
Provide a place in sysfs for the extcon objects.
This allows accessing extcon specific variables.
The name of extcon object denoted as ... is the name given
with extcon_dev_register.
What: /sys/class/extcon/.../name
Date: December 2011
Contact: MyungJoo Ham <myungjoo.ham@samsung.com>
Description:
The /sys/class/extcon/.../name shows the name of the extcon
object. If the extcon object has an optional callback
"show_name" defined, the callback will provide the name with
this sysfs node.
What: /sys/class/extcon/.../state
Date: December 2011
Contact: MyungJoo Ham <myungjoo.ham@samsung.com>
Description:
The /sys/class/extcon/.../state shows the cable attach/detach
information of the corresponding extcon object. If the extcon
objecct has an optional callback "show_state" defined, the
callback will provide the name with this sysfs node.
......@@ -140,4 +140,6 @@ source "drivers/virt/Kconfig"
source "drivers/devfreq/Kconfig"
source "drivers/extcon/Kconfig"
endmenu
......@@ -134,3 +134,4 @@ obj-$(CONFIG_VIRT_DRIVERS) += virt/
obj-$(CONFIG_HYPERV) += hv/
obj-$(CONFIG_PM_DEVFREQ) += devfreq/
obj-$(CONFIG_EXTCON) += extcon/
menuconfig EXTCON
tristate "External Connector Class (extcon) support"
help
Say Y here to enable external connector class (extcon) support.
This allows monitoring external connectors by userspace
via sysfs and uevent and supports external connectors with
multiple states; i.e., an extcon that may have multiple
cables attached. For example, an external connector of a device
may be used to connect an HDMI cable and a AC adaptor, and to
host USB ports. Many of 30-pin connectors including PDMI are
also good examples.
if EXTCON
comment "Extcon Device Drivers"
endif # MULTISTATE_SWITCH
#
# Makefile for external connector class (extcon) devices
#
obj-$(CONFIG_EXTCON) += extcon_class.o
/*
* 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 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.
*/
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;
if (edev->state != state) {
edev->state = state;
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);
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)
{
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) */
dev_set_drvdata(edev->dev, edev);
edev->state = 0;
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");
/*
* 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 switch class driver
* 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.
*
*/
#ifndef __LINUX_EXTCON_H__
#define __LINUX_EXTCON_H__
/**
* struct extcon_dev - An extcon device represents one external connector.
* @name The name of this extcon device. Parent device name is used
* if NULL.
* @print_name An optional callback to override the method to print the
* name of the extcon device.
* @print_state An optional callback to override the method to print the
* status of the extcon device.
* @dev Device of this extcon. Do not provide at register-time.
* @state Attach/detach state of this extcon. Do not provide at
* register-time
*
* In most cases, users only need to provide "User initializing data" of
* this struct when registering an extcon. In some exceptional cases,
* optional callbacks may be needed. However, the values in "internal data"
* are overwritten by register function.
*/
struct extcon_dev {
/* --- Optional user initializing data --- */
const char *name;
/* --- Optional callbacks to override class functions --- */
ssize_t (*print_name)(struct extcon_dev *edev, char *buf);
ssize_t (*print_state)(struct extcon_dev *edev, char *buf);
/* --- Internal data. Please do not set. --- */
struct device *dev;
u32 state;
};
#if IS_ENABLED(CONFIG_EXTCON)
extern int extcon_dev_register(struct extcon_dev *edev, struct device *dev);
extern void extcon_dev_unregister(struct extcon_dev *edev);
static inline u32 extcon_get_state(struct extcon_dev *edev)
{
return edev->state;
}
extern void extcon_set_state(struct extcon_dev *edev, u32 state);
#else /* CONFIG_EXTCON */
static inline int extcon_dev_register(struct extcon_dev *edev,
struct device *dev)
{
return 0;
}
static inline void extcon_dev_unregister(struct extcon_dev *edev) { }
static inline u32 extcon_get_state(struct extcon_dev *edev)
{
return 0;
}
static inline void extcon_set_state(struct extcon_dev *edev, u32 state) { }
#endif /* CONFIG_EXTCON */
#endif /* __LINUX_EXTCON_H__ */
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