linux/drivers/video/backlight/backlight.c
Richard Purdie 599a52d126 backlight: Separate backlight properties from backlight ops pointers
Per device data such as brightness belongs to the indivdual device
and should therefore be separate from the the backlight operation
function pointers. This patch splits the two types of data and
allows simplifcation of some code.

Signed-off-by: Richard Purdie <rpurdie@rpsys.net>
2007-02-20 09:26:53 +00:00

315 lines
8.1 KiB
C

/*
* 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>
#ifdef CONFIG_PMAC_BACKLIGHT
#include <asm/backlight.h>
#endif
#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 && event != FB_EVENT_CONBLANK)
return 0;
bd = container_of(self, struct backlight_device, fb_notif);
mutex_lock(&bd->ops_lock);
if (bd->ops)
if (!bd->ops->check_fb ||
bd->ops->check_fb(evdata->info)) {
bd->props.fb_blank = *(int *)evdata->data;
backlight_update_status(bd);
}
mutex_unlock(&bd->ops_lock);
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)
{
struct backlight_device *bd = to_backlight_device(cdev);
return sprintf(buf, "%d\n", bd->props.power);
}
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;
mutex_lock(&bd->ops_lock);
if (bd->ops) {
pr_debug("backlight: set power to %d\n", power);
bd->props.power = power;
backlight_update_status(bd);
rc = count;
}
mutex_unlock(&bd->ops_lock);
return rc;
}
static ssize_t backlight_show_brightness(struct class_device *cdev, char *buf)
{
struct backlight_device *bd = to_backlight_device(cdev);
return sprintf(buf, "%d\n", bd->props.brightness);
}
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;
mutex_lock(&bd->ops_lock);
if (bd->ops) {
if (brightness > bd->props.max_brightness)
rc = -EINVAL;
else {
pr_debug("backlight: set brightness to %d\n",
brightness);
bd->props.brightness = brightness;
backlight_update_status(bd);
rc = count;
}
}
mutex_unlock(&bd->ops_lock);
return rc;
}
static ssize_t backlight_show_max_brightness(struct class_device *cdev, char *buf)
{
struct backlight_device *bd = to_backlight_device(cdev);
return sprintf(buf, "%d\n", bd->props.max_brightness);
}
static ssize_t backlight_show_actual_brightness(struct class_device *cdev,
char *buf)
{
int rc = -ENXIO;
struct backlight_device *bd = to_backlight_device(cdev);
mutex_lock(&bd->ops_lock);
if (bd->ops && bd->ops->get_brightness)
rc = sprintf(buf, "%d\n", bd->ops->get_brightness(bd));
mutex_unlock(&bd->ops_lock);
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).
* @ops: the backlight operations 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,
struct device *dev,
void *devdata,
struct backlight_ops *ops)
{
int i, rc;
struct backlight_device *new_bd;
pr_debug("backlight_device_alloc: name=%s\n", name);
new_bd = kzalloc(sizeof(struct backlight_device), GFP_KERNEL);
if (!new_bd)
return ERR_PTR(-ENOMEM);
mutex_init(&new_bd->update_lock);
mutex_init(&new_bd->ops_lock);
new_bd->ops = ops;
new_bd->class_dev.class = &backlight_class;
new_bd->class_dev.dev = dev;
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 (rc) {
kfree(new_bd);
return ERR_PTR(rc);
}
rc = backlight_register_fb(new_bd);
if (rc) {
class_device_unregister(&new_bd->class_dev);
return ERR_PTR(rc);
}
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 (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);
}
}
#ifdef CONFIG_PMAC_BACKLIGHT
mutex_lock(&pmac_backlight_mutex);
if (!pmac_backlight)
pmac_backlight = new_bd;
mutex_unlock(&pmac_backlight_mutex);
#endif
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);
#ifdef CONFIG_PMAC_BACKLIGHT
mutex_lock(&pmac_backlight_mutex);
if (pmac_backlight == bd)
pmac_backlight = NULL;
mutex_unlock(&pmac_backlight_mutex);
#endif
for (i = 0; i < ARRAY_SIZE(bl_class_device_attributes); i++)
class_device_remove_file(&bd->class_dev,
&bl_class_device_attributes[i]);
mutex_lock(&bd->ops_lock);
bd->ops = NULL;
mutex_unlock(&bd->ops_lock);
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");