[PATCH 08/13] extcon: extcon-class: simplify extcon_updata_state() function

From: Robert Baldyga
Date: Thu Apr 10 2014 - 09:20:05 EST


This patch simplifies extcon_updata_state() function. There is greatly
simplified kobject_uevent preparation. Also meaning of variable passed
to raw_notifier_call_chain() (and in effect to _call_per_cable()) has
changed. Now positions on ones in variable 'val' in _call_per_cable()
indicates numbers of cables which changed their status. It allowed
to simplify also _call_per_cable() function.

Signed-off-by: Robert Baldyga <r.baldyga@xxxxxxxxxxx>
---
drivers/extcon/extcon-class.c | 81 ++++++++++++++++-------------------------
include/linux/extcon.h | 1 -
2 files changed, 31 insertions(+), 51 deletions(-)

diff --git a/drivers/extcon/extcon-class.c b/drivers/extcon/extcon-class.c
index 2659805..ce76c08 100644
--- a/drivers/extcon/extcon-class.c
+++ b/drivers/extcon/extcon-class.c
@@ -206,59 +206,48 @@ int extcon_update_state(struct extcon_dev *edev, u32 mask, u32 state)
{
char name_buf[120];
char state_buf[120];
- char *prop_buf;
+ char *tmp;
char *envp[3];
int env_offset = 0;
int length;
unsigned long flags;
+ u32 change;

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))) {
+ change = (edev->state & mask) ^ (state & mask);
+ if (change) {
+ if (check_mutually_exclusive(edev, edev->state ^ change)) {
spin_unlock_irqrestore(&edev->lock, flags);
return -EPERM;
}

- 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) {
- 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;
- /* Unlock early before uevent */
- spin_unlock_irqrestore(&edev->lock, flags);
+ edev->state ^= change;

- 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);
+ raw_notifier_call_chain(&edev->nh, change, edev);
+
+ tmp = name_buf + sprintf(name_buf, "NAME=");
+ length = name_show(&edev->dev, NULL, tmp);
+ if (length > 0) {
+ if (tmp[length - 1] == '\n')
+ tmp[length - 1] = 0;
+ envp[env_offset++] = name_buf;
+ }

- dev_err(&edev->dev, "out of memory in extcon_set_state\n");
- kobject_uevent(&edev->dev.kobj, KOBJ_CHANGE);
+ tmp = state_buf + sprintf(state_buf, "STATE=");
+ length = state_show(&edev->dev, NULL, tmp);
+ if (length > 0) {
+ if (tmp[length - 1] == '\n')
+ tmp[length - 1] = 0;
+ 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);
} else {
/* No changes */
spin_unlock_irqrestore(&edev->lock, flags);
@@ -464,18 +453,10 @@ static int _call_per_cable(struct notifier_block *nb, unsigned long val,
{
struct extcon_cable_nb *obj = container_of(nb,
struct extcon_cable_nb, internal_nb);
- struct extcon_dev *edev = ptr;
-
- if ((val & (1 << obj->cable->cable_index)) !=
- (edev->state & (1 << obj->cable->cable_index))) {
- bool cable_state = true;
-
- obj->previous_value = val;
-
- if (val & (1 << obj->cable->cable_index))
- cable_state = false;

- return obj->notifier_function(obj, cable_state);
+ if ((1 << obj->cable->cable_index) & val) {
+ int state = extcon_get_cable_state(obj->cable);
+ return obj->notifier_function(obj, !!state);
}

return NOTIFY_OK;
diff --git a/include/linux/extcon.h b/include/linux/extcon.h
index 939a7b0..4194931 100644
--- a/include/linux/extcon.h
+++ b/include/linux/extcon.h
@@ -177,7 +177,6 @@ typedef int (*extcon_notifier_fn_t)(struct extcon_cable_nb *cable_nb,
*/
struct extcon_cable_nb {
struct notifier_block internal_nb;
- unsigned long previous_value;
extcon_notifier_fn_t notifier_function;
struct extcon_cable *cable;
};
--
1.7.9.5

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/