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authorDonggeun Kim <dg77.kim@samsung.com>2012-04-20 14:16:24 +0900
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2012-04-20 09:23:09 -0700
commit74c5d09bd562edc220d6e076b8f1e118819c178f (patch)
tree65f35b6066fe135405797acc419b4bb6f346e4af /drivers/extcon
parentbe48308a24c7651bf968b561dbd590edb8166d62 (diff)
downloadlinux-74c5d09bd562edc220d6e076b8f1e118819c178f.tar.bz2
Extcon: support notification based on the state changes.
State changes of extcon devices have been notified via kobjet_uevent. This patch adds notifier interfaces in order to allow device drivers to get notified easily. Along with notifier interface, extcon_get_extcon_dev() function is added so that device drivers may discover a extcon_dev easily. Signed-off-by: Donggeun Kim <dg77.kim@samsung.com> 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 RFC - Renamed switch to extcon - Bugfix: extcon_dev_unregister() - Bugfix: "edev->dev" is "internal" data. - Added kerneldoc comments. - Reworded comments. Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/extcon')
-rw-r--r--drivers/extcon/extcon_class.c66
1 files changed, 66 insertions, 0 deletions
diff --git a/drivers/extcon/extcon_class.c b/drivers/extcon/extcon_class.c
index 3c46368c279a..83a088f1edc4 100644
--- a/drivers/extcon/extcon_class.c
+++ b/drivers/extcon/extcon_class.c
@@ -36,6 +36,9 @@ struct class *extcon_class;
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)
{
@@ -75,6 +78,9 @@ static ssize_t name_show(struct device *dev, struct device_attribute *attr,
* 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)
{
@@ -84,10 +90,14 @@ void extcon_set_state(struct extcon_dev *edev, u32 state)
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);
@@ -117,6 +127,51 @@ void extcon_set_state(struct extcon_dev *edev, u32 state)
}
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),
@@ -142,6 +197,10 @@ static int create_extcon_class(void)
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);
@@ -194,8 +253,15 @@ int extcon_dev_register(struct extcon_dev *edev, struct device *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: