/*
* Backlight Lowlevel Control Abstraction
*
* Copyright (C) 2003,2004 Hewlett-Packard Company
*
*/
#include <linux/module.h>
#include <linux/init.h>
#include <linux/device.h>
#include <linux/backlight.h>
#include <linux/notifier.h>
#include <linux/ctype.h>
#include <linux/err.h>
#include <linux/fb.h>
#if defined(CONFIG_FB) || (defined(CONFIG_FB_MODULE) && \
defined(CONFIG_BACKLIGHT_CLASS_DEVICE_MODULE))
/* This callback gets called when something important happens inside a
* framebuffer driver. We're looking if that important event is blanking,
* and if it is, we're switching backlight power as well ...
*/
static int fb_notifier_callback(struct notifier_block *self,
unsigned long event, void *data)
{
struct backlight_device *bd;
struct fb_event *evdata = data;
/* If we aren't interested in this event, skip it immediately ... */
if (event != FB_EVENT_BLANK)
return 0;
bd = container_of(self, struct backlight_device, fb_notif);
down(&bd->sem);
if (bd->props)
if (!bd->props->check_fb ||
bd->props->check_fb(evdata->info)) {
bd->props->fb_blank = *(int *)evdata->data;
if (likely(bd->props && bd->props->update_status))
bd->props->update_status(bd);
}
up(&bd->sem);
return 0;
}
static int backlight_register_fb(struct backlight_device *bd)
{
memset(&bd->fb_notif, 0, sizeof(bd->fb_notif));
bd->fb_notif.notifier_call = fb_notifier_callback;
return fb_register_client(&bd->fb_notif);
}
static void backlight_unregister_fb(struct backlight_device *bd)
{
fb_unregister_client(&bd->fb_notif);
}
#else
static inline int backlight_register_fb(struct backlight_device *bd)
{
return 0;
}
static inline void backlight_unregister_fb(struct backlight_device *bd)
{
}
#endif /* CONFIG_FB */
static ssize_t backlight_show_power(struct class_device *cdev, char *buf)
{
int rc = -ENXIO;
struct backlight_device *bd = to_backlight_device(cdev);
down(&bd->sem);
if (likely(bd->props))
rc = sprintf(buf, "%d\n", bd->props->power);
up(&bd->sem);
return rc;
}
static ssize_t backlight_store_power(struct class_device *cdev, const char *buf, size_t count)
{
int rc = -ENXIO;
char *endp;
struct backlight_device *bd = to_backlight_device(cdev);
int power = simple_strtoul(buf, &endp, 0);
size_t size = endp - buf;
if (*endp && isspace(*endp))
size++;
if (size != count)
return -EINVAL;
down(&bd->sem);
if (likely(bd->props)) {
pr_debug("backlight: set power to %d\n", power);
bd->props->power = power;
if (likely(bd->props->update_status))
bd->props->update_status(bd);
rc = count;
}
up(&bd->sem);
return rc;
}
static ssize_t backlight_show_brightness(struct class_device *cdev, char *buf)
{
int rc = -ENXIO;
struct backlight_device *bd = to_backlight_device(cdev);
down(&bd->sem);
if (likely(bd->props))
rc = sprintf(buf, "%d\n", bd->props->brightness);
up(&bd->sem);
return rc;
}
static ssize_t backlight_store_brightness(struct class_device *cdev, const char *buf, size_t count)
{
int rc = -ENXIO;
char *endp;
struct backlight_device *bd = to_backlight_device(cdev);
int brightness = simple_strtoul(buf, &endp, 0);
size_t size = endp - buf;
if (*endp && isspace(*endp))
size++;
if (size != count)
return -EINVAL;
down(&bd->sem);
if (likely(bd->props)) {
if (brightness > bd->props->max_brightness)
rc = -EINVAL;
else {
pr_debug("backlight: set brightness to %d\n",
brightness);
bd->props->brightness = brightness;
if (likely(bd->props->update_status))
bd->props->update_status(bd);
rc = count;
}
}
up(&bd->sem);
return rc;
}
static ssize_t backlight_show_max_brightness(struct class_device *cdev, char *buf)
{
int rc = -ENXIO;
struct backlight_device *bd = to_backlight_device(cdev);
down(&bd->sem);
if (likely(bd->props))
rc = sprintf(buf, "%d\n", bd->props->max_brightness);
up(&bd->sem);
return rc;
}
static ssize_t backlight_show_actual_brightness(struct class_device *cdev,
char *buf)
{
int rc = -ENXIO;
struct backlight_device *bd = to_backlight_device(cdev);
down(&bd->sem);
if (likely(bd->props && bd->props->get_brightness))
rc = sprintf(buf, "%d\n", bd->props->get_brightness(bd));
up(&bd->sem);
return rc;
}
static void backlight_class_release(struct class_device *dev)
{
struct backlight_device *bd = to_backlight_device(dev);
kfree(bd);
}
static struct class backlight_class = {
.name = "backlight",
.release = backlight_class_release,
};
#define DECLARE_ATTR(_name,_mode,_show,_store) \
{ \
.attr = { .name = __stringify(_name), .mode = _mode, .owner = THIS_MODULE }, \
.show = _show, \
.store = _store, \
}
static const struct class_device_attribute bl_class_device_attributes[] = {
DECLARE_ATTR(power, 0644, backlight_show_power, backlight_store_power),
DECLARE_ATTR(brightness, 0644, backlight_show_brightness,
backlight_store_brightness),
DECLARE_ATTR(actual_brightness, 0444, backlight_show_actual_brightness,
NULL),
DECLARE_ATTR(max_brightness, 0444, backlight_show_max_brightness, NULL),
};
/**
* backlight_device_register - create and register a new object of
* backlight_device class.
* @name: the name of the new object(must be the same as the name of the
* respective framebuffer device).
* @devdata: an optional pointer to be stored in the class_device. The
* methods may retrieve it by using class_get_devdata(&bd->class_dev).
* @bp: the backlight properties structure.
*
* Creates and registers new backlight class_device. Returns either an
* ERR_PTR() or a pointer to the newly allocated device.
*/
struct backlight_device *backlight_device_register(const char *name, void *devdata,
struct backlight_properties *bp)
{
int i, rc;
struct backlight_device *new_bd;
pr_debug("backlight_device_alloc: name=%s\n", name);
new_bd = kmalloc(sizeof(struct backlight_device), GFP_KERNEL);
if (unlikely(!new_bd))
return ERR_PTR(-ENOMEM);
init_MUTEX(&new_bd->sem);
new_bd->props = bp;
memset(&new_bd->class_dev, 0, sizeof(new_bd->class_dev));
new_bd->class_dev.class = &backlight_class;
strlcpy(new_bd->class_dev.class_id, name, KOBJ_NAME_LEN);
class_set_devdata(&new_bd->class_dev, devdata);
rc = class_device_register(&new_bd->class_dev);
if (unlikely(rc)) {
error: kfree(new_bd);
return ERR_PTR(rc);
}
rc = backlight_register_fb(new_bd);
if (unlikely(rc))
goto error;
for (i = 0; i < ARRAY_SIZE(bl_class_device_attributes); i++) {
rc = class_device_create_file(&new_bd->class_dev,
&bl_class_device_attributes[i]);
if (unlikely(rc)) {
while (--i >= 0)
class_device_remove_file(&new_bd->class_dev,
&bl_class_device_attributes[i]);
class_device_unregister(&new_bd->class_dev);
/* No need to kfree(new_bd) since release() method was called */
return ERR_PTR(rc);
}
}
return new_bd;
}
EXPORT_SYMBOL(backlight_device_register);
/**
* backlight_device_unregister - unregisters a backlight device object.
* @bd: the backlight device object to be unregistered and freed.
*
* Unregisters a previously registered via backlight_device_register object.
*/
void backlight_device_unregister(struct backlight_device *bd)
{
int i;
if (!bd)
return;
pr_debug("backlight_device_unregister: name=%s\n", bd->class_dev.class_id);
for (i = 0; i < ARRAY_SIZE(bl_class_device_attributes); i++)
class_device_remove_file(&bd->class_dev,
&bl_class_device_attributes[i]);
down(&bd->sem);
bd->props = NULL;
up(&bd->sem);
backlight_unregister_fb(bd);
class_device_unregister(&bd->class_dev);
}
EXPORT_SYMBOL(backlight_device_unregister);
static void __exit backlight_class_exit(void)
{
class_unregister(&backlight_class);
}
static int __init backlight_class_init(void)
{
return class_register(&backlight_class);
}
/*
* if this is compiled into the kernel, we need to ensure that the
* class is registered before users of the class try to register lcd's
*/
postcore_initcall(backlight_class_init);
module_exit(backlight_class_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Jamey Hicks <jamey.hicks@hp.com>, Andrew Zabolotny <zap@homelink.ru>");
MODULE_DESCRIPTION("Backlight Lowlevel Control Abstraction");
