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authorMyungJoo Ham <myungjoo.ham@samsung.com>2012-04-20 14:16:22 +0900
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2012-04-20 09:21:11 -0700
commitde55d8716ac50a356cea736c29bb7db5ac3d0190 (patch)
treed63f799c7859c97ee7089609bd183d28ca63e2bf /drivers/extcon/extcon_class.c
parent7cd9c9bb57476167e83b7780dbc06d1dd601789d (diff)
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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: MyungJoo Ham <myungjoo.ham@samsung.com> Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com> Reviewed-by: Mark 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 - Removed out-of-date Kconfig entry Changes from v6 - Updated comment/strings - Revised "Android-compatible" mode.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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/extcon/extcon_class.c')
-rw-r--r--drivers/extcon/extcon_class.c236
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");