diff options
Diffstat (limited to 'drivers/extcon/extcon_class.c')
-rw-r--r-- | drivers/extcon/extcon_class.c | 236 |
1 files changed, 236 insertions, 0 deletions
diff --git a/drivers/extcon/extcon_class.c b/drivers/extcon/extcon_class.c new file mode 100644 index 0000000..3c46368 --- /dev/null +++ b/drivers/extcon/extcon_class.c @@ -0,0 +1,236 @@ +/* + * 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"); |