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extcon: Update the prototype of extcon_register_notifier() with enum …
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…extcon

Previously, extcon consumer driver used the extcon_register_interest()
to register the notifier chain and then to receive the notifier event
when external connector's state is changed. When registering the notifier chain
for specific external connector with extcon_register_interest(), it used the
the string name of external connector directly. There are potential problem
because of unclear, non-standard and inconsequent cable name. Namely,
it is not appropriate method to identify each external connector.

So, this patch modify the prototype of extcon_register_notifier() by using
the 'enum extcon' which are the unique id for each external connector
instead of unclear string method.

- Previously, the extcon consumer driver used the extcon_register_interest()
with 'cable_name' to point out the specific external connector. Also. it used
the un-needed structure (struct extcon_specific_cable_nb).
: int extcon_register_interest(struct extcon_specific_cable_nb *obj,
			     const char *extcon_name, const char *cable_name,
			     struct notifier_block *nb)

- Newly, the updated extcon_register_notifier() would definitely support
the same feature to detech the changed state of external connector without
any specific structure (struct extcon_specific_cable_nb).
: int extcon_register_notifier(struct extcon_dev *edev, enum extcon id,
			     struct notifier_block *nb)

This patch support the both extcon_register_interest() and new extcon_register_
notifier(). But the extcon_{register|unregister}_interest() will be deprecated
because extcon core would support the notifier event for extcon consumer driver
with only updated extcon_register_notifier() and 'extcon_specific_cable_nb'
will be removed if there are no extcon consumer driver with legacy
extcon_{register|unregister}_interest().

Signed-off-by: Chanwoo Choi <[email protected]>
Reviewed-by: Krzysztof Kozlowski <[email protected]>
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@chanwoochoi
chanwoochoi committed May 22, 2015
1 parent 8e9bc36 commit 046050f
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Showing 2 changed files with 56 additions and 52 deletions.
91 changes: 48 additions & 43 deletions drivers/extcon/extcon.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -146,6 +146,16 @@ static int find_cable_index_by_name(struct extcon_dev *edev, const char *name)
return find_cable_index_by_id(edev, id);
}

static bool is_extcon_changed(u32 prev, u32 new, int idx, bool *attached)
{
if (((prev >> idx) & 0x1) != ((new >> idx) & 0x1)) {
*attached = new ? true : false;
return true;
}

return false;
}

static ssize_t state_show(struct device *dev, struct device_attribute *attr,
char *buf)
{
Expand Down Expand Up @@ -254,23 +264,27 @@ int extcon_update_state(struct extcon_dev *edev, u32 mask, u32 state)
char *envp[3];
int env_offset = 0;
int length;
int index;
unsigned long flags;
bool attached;

spin_lock_irqsave(&edev->lock, flags);

if (edev->state != ((edev->state & ~mask) | (state & mask))) {
u32 old_state = edev->state;

if (check_mutually_exclusive(edev, (edev->state & ~mask) |
(state & mask))) {
spin_unlock_irqrestore(&edev->lock, flags);
return -EPERM;
}

for (index = 0; index < edev->max_supported; index++) {
if (is_extcon_changed(edev->state, state, index, &attached))
raw_notifier_call_chain(&edev->nh[index], attached, edev);
}

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) {
Expand Down Expand Up @@ -423,29 +437,6 @@ struct extcon_dev *extcon_get_extcon_dev(const char *extcon_name)
}
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))) {
bool cable_state = true;

obj->previous_value = val;

if (val & (1 << obj->cable_index))
cable_state = false;

return obj->user_nb->notifier_call(obj->user_nb,
cable_state, ptr);
}

return NOTIFY_OK;
}

/**
* extcon_register_interest() - Register a notifier for a state change of a
* specific cable, not an entier set of cables of a
Expand Down Expand Up @@ -491,11 +482,10 @@ int extcon_register_interest(struct extcon_specific_cable_nb *obj,

obj->user_nb = nb;

obj->internal_nb.notifier_call = _call_per_cable;

spin_lock_irqsave(&obj->edev->lock, flags);
ret = raw_notifier_chain_register(&obj->edev->nh,
&obj->internal_nb);
ret = raw_notifier_chain_register(
&obj->edev->nh[obj->cable_index],
obj->user_nb);
spin_unlock_irqrestore(&obj->edev->lock, flags);
} else {
struct class_dev_iter iter;
Expand Down Expand Up @@ -538,7 +528,8 @@ int extcon_unregister_interest(struct extcon_specific_cable_nb *obj)
return -EINVAL;

spin_lock_irqsave(&obj->edev->lock, flags);
ret = raw_notifier_chain_unregister(&obj->edev->nh, &obj->internal_nb);
ret = raw_notifier_chain_unregister(
&obj->edev->nh[obj->cable_index], obj->user_nb);
spin_unlock_irqrestore(&obj->edev->lock, flags);

return ret;
Expand All @@ -548,21 +539,24 @@ EXPORT_SYMBOL_GPL(extcon_unregister_interest);
/**
* extcon_register_notifier() - Register a notifiee to get notified by
* any attach status changes from the extcon.
* @edev: the extcon device.
* @edev: the extcon device that has the external connecotr.
* @id: the unique id of each external connector in extcon enumeration.
* @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)
int extcon_register_notifier(struct extcon_dev *edev, enum extcon id,
struct notifier_block *nb)
{
unsigned long flags;
int ret;
int ret, idx;

idx = find_cable_index_by_id(edev, id);

spin_lock_irqsave(&edev->lock, flags);
ret = raw_notifier_chain_register(&edev->nh, nb);
ret = raw_notifier_chain_register(&edev->nh[idx], nb);
spin_unlock_irqrestore(&edev->lock, flags);

return ret;
Expand All @@ -571,17 +565,20 @@ EXPORT_SYMBOL_GPL(extcon_register_notifier);

/**
* extcon_unregister_notifier() - Unregister a notifiee from the extcon device.
* @edev: the extcon device.
* @nb: a registered notifier block to be unregistered.
* @edev: the extcon device that has the external connecotr.
* @id: the unique id of each external connector in extcon enumeration.
* @nb: a notifier block to be registered.
*/
int extcon_unregister_notifier(struct extcon_dev *edev,
struct notifier_block *nb)
int extcon_unregister_notifier(struct extcon_dev *edev, enum extcon id,
struct notifier_block *nb)
{
unsigned long flags;
int ret;
int ret, idx;

idx = find_cable_index_by_id(edev, id);

spin_lock_irqsave(&edev->lock, flags);
ret = raw_notifier_chain_unregister(&edev->nh, nb);
ret = raw_notifier_chain_unregister(&edev->nh[idx], nb);
spin_unlock_irqrestore(&edev->lock, flags);

return ret;
Expand Down Expand Up @@ -893,7 +890,15 @@ int extcon_dev_register(struct extcon_dev *edev)

spin_lock_init(&edev->lock);

RAW_INIT_NOTIFIER_HEAD(&edev->nh);
edev->nh = devm_kzalloc(&edev->dev,
sizeof(*edev->nh) * edev->max_supported, GFP_KERNEL);
if (!edev->nh) {
ret = -ENOMEM;
goto err_dev;
}

for (index = 0; index < edev->max_supported; index++)
RAW_INIT_NOTIFIER_HEAD(&edev->nh[index]);

dev_set_drvdata(&edev->dev, edev);
edev->state = 0;
Expand Down
17 changes: 8 additions & 9 deletions include/linux/extcon.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -116,7 +116,7 @@ struct extcon_dev {

/* Internal data. Please do not set. */
struct device dev;
struct raw_notifier_head nh;
struct raw_notifier_head *nh;
struct list_head entry;
int max_supported;
spinlock_t lock; /* could be called by irq handler */
Expand Down Expand Up @@ -155,16 +155,13 @@ struct extcon_cable {
/**
* 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;
Expand Down Expand Up @@ -240,10 +237,10 @@ extern int extcon_unregister_interest(struct extcon_specific_cable_nb *nb);
* we do not recommend to use this for 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,
extern int extcon_register_notifier(struct extcon_dev *edev, enum extcon id,
struct notifier_block *nb);
extern int extcon_unregister_notifier(struct extcon_dev *edev, enum extcon id,
struct notifier_block *nb);
extern int extcon_unregister_notifier(struct extcon_dev *edev,
struct notifier_block *nb);

/*
* Following API get the extcon device from devicetree.
Expand Down Expand Up @@ -333,13 +330,15 @@ static inline struct extcon_dev *extcon_get_extcon_dev(const char *extcon_name)
}

static inline int extcon_register_notifier(struct extcon_dev *edev,
struct notifier_block *nb)
enum extcon id,
struct notifier_block *nb)
{
return 0;
}

static inline int extcon_unregister_notifier(struct extcon_dev *edev,
struct notifier_block *nb)
enum extcon id,
struct notifier_block *nb)
{
return 0;
}
Expand Down

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