[PATCH 2/2] extcon: Update the prototype of extcon_register_notifier() with enum extcon

Chanwoo Choi
2015-05-15T14:31:36Z

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 <cw00.choi@samsung.com>
Cc: MyungJoo Ham <myungjoo.ham@samsung.com>
Cc: George Cherian <george.cherian@ti.com>
Cc: Felipe Balbi <balbi@ti.com>
Cc: Aaro Koskinen <aaro.koskinen@iki.fi>
---
drivers/extcon/extcon.c | 91 ++++++++++++++++++++++++++-----------------------
include/linux/extcon.h | 17 +++++----
2 files changed, 56 insertions(+), 52 deletions(-)

diff --git a/drivers/extcon/extcon.c b/drivers/extcon/extcon.c
index 4aeb585..14c8c95 100644
--- a/drivers/extcon/extcon.c
+++ b/drivers/extcon/extcon.c
@@ -111,6 +111,16 @@ static int check_mutually_exclusive(struct extcon_dev *edev, u32 new_state)
return 0;
}

+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)
{
@@ -219,23 +229,27 @@ 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) {
@@ -433,29 +447,6 @@ 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))) {
- 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
@@ -501,11 +492,10 @@ 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;
@@ -548,7 +538,8 @@ 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;
@@ -558,21 +549,24 @@ 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 = extcon_find_cable_index(edev, extcon_name[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;
@@ -581,17 +575,20 @@ 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 = extcon_find_cable_index(edev, extcon_name[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;
@@ -903,7 +900,15 @@ 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;
diff --git a/include/linux/extcon.h b/include/linux/extcon.h
index de158a1..918ba89 100644
--- a/include/linux/extcon.h
+++ b/include/linux/extcon.h
@@ -135,7 +135,7 @@ 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 */
@@ -174,8 +174,6 @@ 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.
@@ -183,7 +181,6 @@ struct extcon_cable {
* @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;
@@ -259,10 +256,10 @@ 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.
@@ -352,13 +349,15 @@ 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;
}
--
1.8.5.5