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Subject[PATCH v5 3/5] Extcon: support multiple states at a device.
Date
One switch device (e.g., MUIC(MAX8997, MAX77686, ...), and some 30-pin
devices) may have multiple cables attached. For example, one
30-pin port may inhabit a USB cable, an HDMI cable, and a mic.
Thus, one switch device requires multiple state bits each representing
a type of cable.

For such purpose, we use the 32bit state variable; thus, up to 32
different type of cables may be defined for a switch device. The list of
possible cables is defined by the array of cable names in the switch_dev
struct given to the class.
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>

--
Changes from V4
- Bugfixes after more testing at Exynos4412 boards with userspace
processses.

Changes from V3
- Bugfixes after more testing at Exynos4412 boards.

Changes from V2
- State can be stored by user
- Documentation updated

Changes from RFC
- Switch is renamed to extcon
- Added kerneldoc comments
- Added APIs to support "standard" cable names
- Added helper APIs to support notifier block registration with cable
name.
- Regrouped function list in the header file.

Extcon: extcon framework bugfix

This patch fixes the following issues:
1. NULL pointer error due to device_attribute
2. The message of 'BUG: sleeping function called from invalid context ...'
is shown when calling get_zeroed_page in spin locked
3. Handling old state had bug that not properly interpretting the
semantics of values.
4. Incorrect sysfs node format (state)

Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>
---
Documentation/ABI/testing/sysfs-class-extcon | 38 +++-
drivers/extcon/extcon_class.c | 310 ++++++++++++++++++++++++-
include/linux/extcon.h | 151 +++++++++++++
3 files changed, 482 insertions(+), 17 deletions(-)
diff --git a/Documentation/ABI/testing/sysfs-class-extcon b/Documentation/ABI/testing/sysfs-class-extcon
index 59a4b1c..31bb609 100644
--- a/Documentation/ABI/testing/sysfs-class-extcon
+++ b/Documentation/ABI/testing/sysfs-class-extcon
@@ -7,6 +7,14 @@ Description:
The name of extcon object denoted as ... is the name given
with extcon_dev_register.

+ One extcon device denotes a single external connector
+ port. An external connector may have multiple cables
+ attached simultaneously. Many of docks, cradles, and
+ accessory cables have such capability. For example,
+ the 30-pin port of Nuri board (/arch/arm/mach-exynos)
+ may have both HDMI and Charger attached, or analog audio,
+ video, and USB cables attached simulteneously.
+
What: /sys/class/extcon/.../name
Date: December 2011
Contact: MyungJoo Ham <myungjoo.ham@samsung.com>
@@ -20,7 +28,29 @@ 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.
+ The /sys/class/extcon/.../state shows and stores the cable
+ attach/detach information of the corresponding extcon object.
+ If the extcon objecct has an optional callback "show_state"
+ defined, the showing function is overriden with the optional
+ callback.
+
+ If the default callback for showing function is used, the
+ format is like this:
+ # cat state
+ USB_OTG=1
+ HDMI=0
+ TA=1
+ EAR_JACK=0
+ #
+ In this example, the extcon device have USB_OTG and TA
+ cables attached and HDMI and EAR_JACK cables detached.
+
+ There are two methods to update state of extcon.
+ Method 1.
+ echo CABLE_NAME [0|1] > state
+ Method 2.
+ echo 0xHEX > state
+
+ Method 1 updates the state (0 or 1) of the
+ corresponding cable (either the name or index of the cable).
+ Method 2 updates the whole state of the extcon dev.
diff --git a/drivers/extcon/extcon_class.c b/drivers/extcon/extcon_class.c
index 763cf4d..2803bd0 100644
--- a/drivers/extcon/extcon_class.c
+++ b/drivers/extcon/extcon_class.c
@@ -31,6 +31,25 @@
#include <linux/extcon.h>
#include <linux/slab.h>

+const char *extcon_cable_name[] = {
+ [EXTCON_USB] = "USB",
+ [EXTCON_USB_HOST] = "USB-Host",
+ [EXTCON_TA] = "TA",
+ [EXTCON_FAST_CHARGER] = "Fast-charger",
+ [EXTCON_SLOW_CHARGER] = "Slow-charger",
+ [EXTCON_CHARGE_DOWNSTREAM] = "Charge-downstream",
+ [EXTCON_HDMI] = "HDMI",
+ [EXTCON_MHL] = "MHL",
+ [EXTCON_DVI] = "DVI",
+ [EXTCON_VGA] = "VGA",
+ [EXTCON_DOCK] = "Dock",
+ [EXTCON_AUDIO_IN] = "Audio-in",
+ [EXTCON_AUDIO_OUT] = "Audio-out",
+ [EXTCON_VIDEO_IN] = "Video-in",
+ [EXTCON_VIDEO_OUT] = "Video-out",
+
+ NULL,
+};
struct class *extcon_class;
struct class *extcon_class_for_android;

@@ -40,6 +59,7 @@ static DEFINE_MUTEX(extcon_dev_list_lock);
static ssize_t state_show(struct device *dev, struct device_attribute *attr,
char *buf)
{
+ int i, count = 0;
struct extcon_dev *edev = (struct extcon_dev *) dev_get_drvdata(dev);

if (edev->print_state) {
@@ -49,7 +69,55 @@ static ssize_t state_show(struct device *dev, struct device_attribute *attr,
return ret;
/* Use default if failed */
}
- return sprintf(buf, "%u\n", edev->state);
+
+ if (edev->max_supported == 0)
+ return sprintf(buf, "%u\n", edev->state);
+
+ for (i = 0; i < SUPPORTED_CABLE_MAX; i++) {
+ if (!edev->supported_cable[i])
+ break;
+ count += sprintf(buf + count, "%s=%d\n",
+ edev->supported_cable[i],
+ !!(edev->state & (1 << i)));
+ }
+
+ return count;
+}
+
+void extcon_set_state(struct extcon_dev *edev, u32 state);
+static ssize_t state_store(struct device *dev, struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ u32 state;
+ ssize_t ret = 0;
+ int enabled;
+ char *buffer = kzalloc(count + 1, GFP_KERNEL);
+ struct extcon_dev *edev = (struct extcon_dev *) dev_get_drvdata(dev);
+
+ /* Format: /Documentation/ABI/testing/sysfs-class-extcon */
+ ret = sscanf(buf, "%s %d", buffer, &enabled);
+
+ /* TODO: remove before submit */
+ pr_info("[%s][%d]\n", buffer, enabled);
+
+ if (ret == 2) {
+ /* Method 1 */
+ ret = extcon_set_cable_state(edev, buffer, enabled);
+ pr_info("Method 1\n");
+ } else if (ret == 1) {
+ /* Method 2 */
+ ret = sscanf(buf, "0x%x", &state);
+ pr_info("Method 2 with 0x%x\n", state);
+ if (ret == 0)
+ ret = -EINVAL;
+ else
+ extcon_set_state(edev, state);
+ } else {
+ ret = -EINVAL;
+ }
+
+ kfree(buffer);
+ return ret;
}

static ssize_t name_show(struct device *dev, struct device_attribute *attr,
@@ -68,8 +136,10 @@ static ssize_t name_show(struct device *dev, struct device_attribute *attr,
}

/**
- * extcon_set_state() - Set the cable attach states of the extcon device.
+ * extcon_update_state() - Update the cable attach states of the extcon device
+ * only for the masked bits.
* @edev: the extcon device
+ * @mask: the bit mask to designate updated bits.
* @state: new cable attach status for @edev
*
* Changing the state sends uevent with environment variable containing
@@ -77,10 +147,10 @@ static ssize_t name_show(struct device *dev, struct device_attribute *attr,
* 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.
+ * Note that the notifier provides which bits are changed in the state
+ * variable with the val parameter (second) to the callback.
*/
-void extcon_set_state(struct extcon_dev *edev, u32 state)
+void extcon_update_state(struct extcon_dev *edev, u32 mask, u32 state)
{
char name_buf[120];
char state_buf[120];
@@ -88,15 +158,20 @@ void extcon_set_state(struct extcon_dev *edev, u32 state)
char *envp[3];
int env_offset = 0;
int length;
- u32 old_state = edev->state;
+ unsigned long flags;

- if (edev->state != state) {
- edev->state = state;
+ spin_lock_irqsave(&edev->lock, flags);

- raw_notifier_call_chain(&edev->nh, old_state ^ edev->state,
- edev);
+ if (edev->state != ((edev->state & ~mask) | (state & mask))) {
+ u32 old_state = edev->state;

- prop_buf = (char *)get_zeroed_page(GFP_KERNEL);
+ edev->state &= ~mask;
+ edev->state |= state & mask;
+
+ raw_notifier_call_chain(&edev->nh, old_state, edev);
+
+ /* This could be in interrupt handler */
+ prop_buf = (char *)get_zeroed_page(GFP_ATOMIC);
if (prop_buf) {
length = name_show(edev->dev, NULL, prop_buf);
if (length > 0) {
@@ -115,17 +190,132 @@ void extcon_set_state(struct extcon_dev *edev, u32 state)
envp[env_offset++] = state_buf;
}
envp[env_offset] = NULL;
+ /* Unlock early before uevent */
+ spin_unlock_irqrestore(&edev->lock, flags);
+
kobject_uevent_env(&edev->dev->kobj, KOBJ_CHANGE, envp);
free_page((unsigned long)prop_buf);
} else {
+ /* Unlock early before uevent */
+ spin_unlock_irqrestore(&edev->lock, flags);
+
dev_err(edev->dev, "out of memory in extcon_set_state\n");
kobject_uevent(&edev->dev->kobj, KOBJ_CHANGE);
}
+ } else {
+ /* No changes */
+ spin_unlock_irqrestore(&edev->lock, flags);
}
}
+EXPORT_SYMBOL_GPL(extcon_update_state);
+
+/**
+ * extcon_set_state() - Set the cable attach states of the extcon device.
+ * @edev: the extcon device
+ * @state: new cable attach status for @edev
+ *
+ * Note that notifier provides which bits are changed in the state
+ * variable with the val parameter (second) to the callback.
+ */
+void extcon_set_state(struct extcon_dev *edev, u32 state)
+{
+ extcon_update_state(edev, 0xffffffff, state);
+}
EXPORT_SYMBOL_GPL(extcon_set_state);

/**
+ * extcon_find_cable_index() - Get the cable index based on the cable name.
+ * @edev: the extcon device that has the cable.
+ * @cable_name: cable name to be searched.
+ *
+ * Note that accessing a cable state based on cable_index is faster than
+ * cable_name because using cable_name induces a loop with strncmp().
+ * Thus, when get/set_cable_state is repeatedly used, using cable_index
+ * is recommended.
+ */
+int extcon_find_cable_index(struct extcon_dev *edev, const char *cable_name)
+{
+ int i;
+
+ if (edev->supported_cable) {
+ for (i = 0; edev->supported_cable[i]; i++) {
+ if (!strncmp(edev->supported_cable[i],
+ cable_name, CABLE_NAME_MAX))
+ return i;
+ }
+ }
+
+ return -EINVAL;
+}
+EXPORT_SYMBOL_GPL(extcon_find_cable_index);
+
+/**
+ * extcon_get_cable_state_() - Get the status of a specific cable.
+ * @edev: the extcon device that has the cable.
+ * @index: cable index that can be retrieved by extcon_find_cable_index().
+ */
+int extcon_get_cable_state_(struct extcon_dev *edev, int index)
+{
+ if (index < 0 || (edev->max_supported && edev->max_supported <= index))
+ return -EINVAL;
+
+ return !!(edev->state & (1 << index));
+}
+EXPORT_SYMBOL_GPL(extcon_get_cable_state_);
+
+/**
+ * extcon_get_cable_state() - Get the status of a specific cable.
+ * @edev: the extcon device that has the cable.
+ * @cable_name: cable name.
+ *
+ * Note that this is slower than extcon_get_cable_state_.
+ */
+int extcon_get_cable_state(struct extcon_dev *edev, const char *cable_name)
+{
+ return extcon_get_cable_state_(edev, extcon_find_cable_index
+ (edev, cable_name));
+}
+EXPORT_SYMBOL_GPL(extcon_get_cable_state);
+
+/**
+ * extcon_get_cable_state_() - Set the status of a specific cable.
+ * @edev: the extcon device that has the cable.
+ * @index: cable index that can be retrieved by extcon_find_cable_index().
+ * @cable_state: the new cable status. The default semantics is
+ * true: attached / false: detached.
+ */
+int extcon_set_cable_state_(struct extcon_dev *edev,
+ int index, bool cable_state)
+{
+ u32 state;
+
+ if (index < 0 || (edev->max_supported && edev->max_supported <= index))
+ return -EINVAL;
+
+ state = cable_state ? (1 << index) : 0;
+ extcon_update_state(edev, 1 << index, state);
+ return 0;
+}
+EXPORT_SYMBOL_GPL(extcon_set_cable_state_);
+
+/**
+ * extcon_get_cable_state() - Set the status of a specific cable.
+ * @edev: the extcon device that has the cable.
+ * @cable_name: cable name.
+ * @cable_state: the new cable status. The default semantics is
+ * true: attached / false: detached.
+ *
+ * Note that this is slower than extcon_set_cable_state_.
+ */
+int extcon_set_cable_state(struct extcon_dev *edev,
+ const char *cable_name, bool cable_state)
+{
+ return extcon_set_cable_state_(edev, extcon_find_cable_index
+ (edev, cable_name), cable_state);
+}
+EXPORT_SYMBOL_GPL(extcon_set_cable_state);
+
+/**
* extcon_get_extcon_dev() - Get the extcon device instance from the name
* @extcon_name: The extcon name provided with extcon_dev_register()
*/
@@ -145,11 +335,88 @@ out:
}
EXPORT_SYMBOL_GPL(extcon_get_extcon_dev);

+static int _call_per_cable(struct notifier_block *nb, unsigned long val,
+ void *ptr)
+{
+ struct extcon_specific_cable_nb *obj = container_of(nb,
+ struct extcon_specific_cable_nb, internal_nb);
+ struct extcon_dev *edev = ptr;
+
+ if ((val & (1 << obj->cable_index)) !=
+ (edev->state & (1 << obj->cable_index))) {
+ obj->previous_value = val;
+ return obj->user_nb->notifier_call(nb, val, ptr);
+ }
+
+ return NOTIFY_OK;
+}
+
+/**
+ * extcon_register_interest() - Register a notifier for a state change of a
+ * specific cable, not a entier set of cables of a
+ * extcon device.
+ * @obj: an empty extcon_specific_cable_nb object to be returned.
+ * @extcon_name: the name of extcon device.
+ * @cable_name: the target cable name.
+ * @nb: the notifier block to get notified.
+ *
+ * Provide an empty extcon_specific_cable_nb. extcon_register_interest() sets
+ * the struct for you.
+ *
+ * extcon_register_interest is a helper function for those who want to get
+ * notification for a single specific cable's status change. If a user wants
+ * to get notification for any changes of all cables of a extcon device,
+ * he/she should use the general extcon_register_notifier().
+ *
+ * Note that the second parameter given to the callback of nb (val) is
+ * "old_state", not the current state. The current state can be retrieved
+ * by looking at the third pameter (edev pointer)'s state value.
+ */
+int extcon_register_interest(struct extcon_specific_cable_nb *obj,
+ const char *extcon_name, const char *cable_name,
+ struct notifier_block *nb)
+{
+ if (!obj || !extcon_name || !cable_name || !nb)
+ return -EINVAL;
+
+ obj->edev = extcon_get_extcon_dev(extcon_name);
+ if (!obj->edev)
+ return -ENODEV;
+
+ obj->cable_index = extcon_find_cable_index(obj->edev, cable_name);
+ if (obj->cable_index < 0)
+ return -ENODEV;
+
+ obj->user_nb = nb;
+
+ obj->internal_nb.notifier_call = _call_per_cable;
+
+ return raw_notifier_chain_register(&obj->edev->nh, &obj->internal_nb);
+}
+
+/**
+ * extcon_unregister_interest() - Unregister the notifier registered by
+ * extcon_register_interest().
+ * @obj: the extcon_specific_cable_nb object returned by
+ * extcon_register_interest().
+ */
+int extcon_unregister_interest(struct extcon_specific_cable_nb *obj)
+{
+ if (!obj)
+ return -EINVAL;
+
+ return raw_notifier_chain_unregister(&obj->edev->nh, &obj->internal_nb);
+}
+
/**
* 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.
+ *
+ * Note that the second parameter given to the callback of nb (val) is
+ * "old_state", not the current state. The current state can be retrieved
+ * by looking at the third pameter (edev pointer)'s state value.
*/
int extcon_register_notifier(struct extcon_dev *edev,
struct notifier_block *nb)
@@ -171,8 +438,9 @@ int extcon_unregister_notifier(struct extcon_dev *edev,
EXPORT_SYMBOL_GPL(extcon_unregister_notifier);

static struct device_attribute extcon_attrs[] = {
- __ATTR_RO(state),
+ __ATTR(state, S_IRUGO | S_IWUSR, state_show, state_store),
__ATTR_RO(name),
+ __ATTR_NULL,
};

static int create_extcon_class(void)
@@ -231,7 +499,7 @@ static void extcon_dev_release(struct device *dev)
*/
int extcon_dev_register(struct extcon_dev *edev, struct device *dev)
{
- int ret;
+ int ret, index = 0;

if (!extcon_class && !edev->use_class_name_switch) {
ret = create_extcon_class();
@@ -244,6 +512,20 @@ int extcon_dev_register(struct extcon_dev *edev, struct device *dev)
return ret;
}

+ if (edev->supported_cable) {
+ /* Get size of array */
+ for (index = 0; edev->supported_cable[index]; index++)
+ ;
+ edev->max_supported = index;
+ } else {
+ edev->max_supported = 0;
+ }
+
+ if (index > SUPPORTED_CABLE_MAX) {
+ dev_err(edev->dev, "extcon: maximum number of supported cables exceeded.\n");
+ return -EINVAL;
+ }
+
edev->dev = kzalloc(sizeof(struct device), GFP_KERNEL);
edev->dev->parent = dev;
if (edev->use_class_name_switch)
@@ -259,6 +541,8 @@ int extcon_dev_register(struct extcon_dev *edev, struct device *dev)
goto err_dev;
}

+ spin_lock_init(&edev->lock);
+
RAW_INIT_NOTIFIER_HEAD(&edev->nh);

dev_set_drvdata(edev->dev, edev);
diff --git a/include/linux/extcon.h b/include/linux/extcon.h
index 1e47e3b..4384d8f 100644
--- a/include/linux/extcon.h
+++ b/include/linux/extcon.h
@@ -24,6 +24,47 @@
#define __LINUX_EXTCON_H__

#include <linux/notifier.h>
+
+#define SUPPORTED_CABLE_MAX 32
+#define CABLE_NAME_MAX 30
+
+/*
+ * The standard cable name is to help support general notifier
+ * and notifee device drivers to share the common names.
+ * Please use standard cable names unless your notifier device has
+ * a very unique and abnormal cable or
+ * the cable type is supposed to be used with only one unique
+ * pair of notifier/notifee devices.
+ *
+ * Please add any other "standard" cables used with extcon dev.
+ *
+ * You may add a dot and number to specify version or specification
+ * of the specific cable if it is required. (e.g., "Fast-charger.18"
+ * and "Fast-charger.10" for 1.8A and 1.0A chargers)
+ * However, the notifee and notifier should be able to handle such
+ * string and if the notifee can negotiate the protocol or idenify,
+ * you don't need such convention. This convention is helpful when
+ * notifier can distinguish but notifiee cannot.
+ */
+enum extcon_cable_name {
+ EXTCON_USB = 0,
+ EXTCON_USB_HOST,
+ EXTCON_TA, /* Travel Adaptor */
+ EXTCON_FAST_CHARGER,
+ EXTCON_SLOW_CHARGER,
+ EXTCON_CHARGE_DOWNSTREAM, /* Charging an external device */
+ EXTCON_HDMI,
+ EXTCON_MHL,
+ EXTCON_DVI,
+ EXTCON_VGA,
+ EXTCON_DOCK,
+ EXTCON_AUDIO_IN,
+ EXTCON_AUDIO_OUT,
+ EXTCON_VIDEO_IN,
+ EXTCON_VIDEO_OUT,
+};
+extern const char *extcon_cable_name[];
+
/**
* struct extcon_dev - An extcon device represents one external connector.
* @name The name of this extcon device. Parent device name is used
@@ -31,6 +72,9 @@
* @use_class_name_switch set true in order to be compatible with
* Android platform, which uses "switch"
* for the class name.
+ * @supported_cable Array of supported cable name ending with NULL.
+ * If supported_cable is NULL, cable name related APIs
+ * are disabled.
* @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
@@ -41,6 +85,8 @@
* @nh Notifier for the state change events from this extcon
* @entry To support list of extcon devices so that uses can search
* for extcon devices based on the extcon name.
+ * @lock
+ * @max_supported Internal value to store the number of cables.
*
* In most cases, users only need to provide "User initializing data" of
* this struct when registering an extcon. In some exceptional cases,
@@ -51,6 +97,7 @@ struct extcon_dev {
/* --- Optional user initializing data --- */
const char *name;
bool use_class_name_switch;
+ const char **supported_cable;

/* --- Optional callbacks to override class functions --- */
ssize_t (*print_name)(struct extcon_dev *edev, char *buf);
@@ -61,6 +108,8 @@ struct extcon_dev {
u32 state;
struct raw_notifier_head nh;
struct list_head entry;
+ spinlock_t lock; /* could be called by irq handler */
+ int max_supported;
};

/**
@@ -81,6 +130,23 @@ struct gpio_extcon_platform_data {
const char *state_off;
};

+/**
+ * struct extcon_specific_cable_nb - An internal data for
+ * extcon_register_interest().
+ * @internal_nb a notifier block bridging extcon notifier and cable notifier.
+ * @user_nb user provided notifier block for events from a specific cable.
+ * @cable_index the target cable.
+ * @edev the target extcon device.
+ * @previous_value the saved previous event value.
+ */
+struct extcon_specific_cable_nb {
+ struct notifier_block internal_nb;
+ struct notifier_block *user_nb;
+ int cable_index;
+ struct extcon_dev *edev;
+ unsigned long previous_value;
+};
+
#ifdef CONFIG_EXTCON

/*
@@ -91,16 +157,54 @@ extern int extcon_dev_register(struct extcon_dev *edev, struct device *dev);
extern void extcon_dev_unregister(struct extcon_dev *edev);
extern struct extcon_dev *extcon_get_extcon_dev(const char *extcon_name);

+/*
+ * get/set/update_state access the 32b encoded state value, which represents
+ * states of all possible cables of the multistate port. For example, if one
+ * calls extcon_set_state(edev, 0x7), it may mean that all the three cables
+ * are attached to the port.
+ */
static inline u32 extcon_get_state(struct extcon_dev *edev)
{
return edev->state;
}

extern void extcon_set_state(struct extcon_dev *edev, u32 state);
+extern void extcon_update_state(struct extcon_dev *edev, u32 mask, u32 state);
+
+/*
+ * get/set_cable_state access each bit of the 32b encoded state value.
+ * They are used to access the status of each cable based on the cable_name
+ * or cable_index, which is retrived by extcon_find_cable_index
+ */
+extern int extcon_find_cable_index(struct extcon_dev *sdev,
+ const char *cable_name);
+extern int extcon_get_cable_state_(struct extcon_dev *edev, int cable_index);
+extern int extcon_set_cable_state_(struct extcon_dev *edev, int cable_index,
+ bool cable_state);
+
+extern int extcon_get_cable_state(struct extcon_dev *edev,
+ const char *cable_name);
+extern int extcon_set_cable_state(struct extcon_dev *edev,
+ const char *cable_name, bool cable_state);
+
+/*
+ * Following APIs are for notifiees (those who want to be notified)
+ * to register a callback for events from a specific cable of the extcon.
+ * Notifiees are the connected device drivers wanting to get notified by
+ * a specific external port of a connection device.
+ */
+extern int extcon_register_interest(struct extcon_specific_cable_nb *obj,
+ const char *extcon_name,
+ const char *cable_name,
+ struct notifier_block *nb);
+extern int extcon_unregister_interest(struct extcon_specific_cable_nb *nb);

/*
* Following APIs are to monitor every action of a notifier.
* Registerer gets notified for every external port of a connection device.
+ * Probably this could be used to debug an action of notifier; however,
+ * we do not recommend to use this at normal 'notifiee' device drivers who
+ * want to be notified by a specific external port of the notifier.
*/
extern int extcon_register_notifier(struct extcon_dev *edev,
struct notifier_block *nb);
@@ -121,6 +225,41 @@ static inline u32 extcon_get_state(struct extcon_dev *edev)
}

static inline void extcon_set_state(struct extcon_dev *edev, u32 state) { }
+
+static inline void extcon_update_state(struct extcon_dev *edev, u32 mask,
+ u32 state)
+{ }
+
+static inline int extcon_find_cable_index(struct extcon_dev *edev,
+ const char *cable_name)
+{
+ return 0;
+}
+
+static inline int extcon_get_cable_state_(struct extcon_dev *edev,
+ int cable_index)
+{
+ return 0;
+}
+
+static inline int extcon_set_cable_state_(struct extcon_dev *edev,
+ int cable_index, bool cable_state)
+{
+ return 0;
+}
+
+static inline int extcon_get_cable_state(struct extcon_dev *edev,
+ const char *cable_name)
+{
+ return 0;
+}
+
+static inline int extcon_set_cable_state(struct extcon_dev *edev,
+ const char *cable_name, int state)
+{
+ return 0;
+}
+
static inline struct extcon_dev *extcon_get_extcon_dev(const char *extcon_name)
{
return NULL;
@@ -138,5 +277,17 @@ static inline int extcon_unregister_notifier(struct extcon_dev *edev,
return 0;
}

+static inline int extcon_register_interest(struct extcon_specific_cable_nb *obj,
+ const char *extcon_name,
+ const char *cable_name,
+ struct notifier_block *nb)
+{
+ return 0;
+}
+
+static inline int extcon_unregister_interest(struct extcon_specific_cable_nb *)
+{
+ return 0;
+}
#endif /* CONFIG_EXTCON */
#endif /* __LINUX_EXTCON_H__ */
--
1.7.4.1


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