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video / backlight: add two APIs for drivers to use

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It is useful to get the backlight device's pointer and use it to set
backlight in some cases(the following patch will make use of it) so add
the two APIs and export them.

Signed-off-by: Aaron Lu <aaron.lu@intel.com>
Acked-by: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Aaron Lu 2016-04-27 20:45:02 +08:00 committed by Rafael J. Wysocki
parent 04974df804
commit f6a4790a54
2 changed files with 36 additions and 19 deletions
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53
drivers/video/backlight/backlight.c
View File

@ -164,6 +164,30 @@ static ssize_t brightness_show(struct device *dev,
return sprintf(buf, "%d\n", bd->props.brightness);
}
int backlight_device_set_brightness(struct backlight_device *bd,
unsigned long brightness)
{
int rc = -ENXIO;
mutex_lock(&bd->ops_lock);
if (bd->ops) {
if (brightness > bd->props.max_brightness)
rc = -EINVAL;
else {
pr_debug("set brightness to %lu\n", brightness);
bd->props.brightness = brightness;
backlight_update_status(bd);
rc = 0;
}
}
mutex_unlock(&bd->ops_lock);
backlight_generate_event(bd, BACKLIGHT_UPDATE_SYSFS);
return rc;
}
EXPORT_SYMBOL(backlight_device_set_brightness);
static ssize_t brightness_store(struct device *dev,
struct device_attribute *attr, const char *buf, size_t count)
{
@ -175,24 +199,9 @@ static ssize_t brightness_store(struct device *dev,
if (rc)
return rc;
rc = -ENXIO;
rc = backlight_device_set_brightness(bd, brightness);
mutex_lock(&bd->ops_lock);
if (bd->ops) {
if (brightness > bd->props.max_brightness)
rc = -EINVAL;
else {
pr_debug("set brightness to %lu\n", brightness);
bd->props.brightness = brightness;
backlight_update_status(bd);
rc = count;
}
}
mutex_unlock(&bd->ops_lock);
backlight_generate_event(bd, BACKLIGHT_UPDATE_SYSFS);
return rc;
return rc ? rc : count;
}
static DEVICE_ATTR_RW(brightness);
@ -380,7 +389,7 @@ struct backlight_device *backlight_device_register(const char *name,
}
EXPORT_SYMBOL(backlight_device_register);
bool backlight_device_registered(enum backlight_type type)
struct backlight_device *backlight_device_get_by_type(enum backlight_type type)
{
bool found = false;
struct backlight_device *bd;
@ -394,7 +403,13 @@ bool backlight_device_registered(enum backlight_type type)
}
mutex_unlock(&backlight_dev_list_mutex);
return found;
return found ? bd : NULL;
}
EXPORT_SYMBOL(backlight_device_get_by_type);
bool backlight_device_registered(enum backlight_type type)
{
return backlight_device_get_by_type(type) ? true : false;
}
EXPORT_SYMBOL(backlight_device_registered);

2
include/linux/backlight.h
View File

@ -144,6 +144,8 @@ extern void backlight_force_update(struct backlight_device *bd,
extern bool backlight_device_registered(enum backlight_type type);
extern int backlight_register_notifier(struct notifier_block *nb);
extern int backlight_unregister_notifier(struct notifier_block *nb);
extern struct backlight_device *backlight_device_get_by_type(enum backlight_type type);
extern int backlight_device_set_brightness(struct backlight_device *bd, unsigned long brightness);
#define to_backlight_device(obj) container_of(obj, struct backlight_device, dev)