linux/drivers/video/backlight/lcd.c
James Simmons 3d5eeaddad [PATCH] backlight: lcd: Remove dependenct from the framebuffer layer
The backlight layer should be independent from the framebuffer layer.  It
can use the services offered by the framebuffer, but its absence should not
prevent the backlight/lcd layer from functioning.

[akpm@osdl.org: cleanups]
Signed-off-by: James Simmons <jsimmons@infradead.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-08 08:29:07 -08:00

282 lines
6.9 KiB
C

/*
* LCD Lowlevel Control Abstraction
*
* Copyright (C) 2003,2004 Hewlett-Packard Company
*
*/
#include <linux/module.h>
#include <linux/init.h>
#include <linux/device.h>
#include <linux/lcd.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_LCD_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 lcd power as well ...
*/
static int fb_notifier_callback(struct notifier_block *self,
unsigned long event, void *data)
{
struct lcd_device *ld;
struct fb_event *evdata = data;
/* If we aren't interested in this event, skip it immediately ... */
if (event != FB_EVENT_BLANK)
return 0;
ld = container_of(self, struct lcd_device, fb_notif);
down(&ld->sem);
if (ld->props)
if (!ld->props->check_fb || ld->props->check_fb(evdata->info))
ld->props->set_power(ld, *(int *)evdata->data);
up(&ld->sem);
return 0;
}
static int lcd_register_fb(struct lcd_device *ld)
{
memset(&ld->fb_notif, 0, sizeof(&ld->fb_notif));
ld->fb_notif.notifier_call = fb_notifier_callback;
return fb_register_client(&ld->fb_notif);
}
static void lcd_unregister_fb(struct lcd_device *ld)
{
fb_unregister_client(&ld->fb_notif);
}
#else
static int lcd_register_fb(struct lcd_device *ld)
{
return 0;
}
static inline void lcd_unregister_fb(struct lcd_device *ld)
{
}
#endif /* CONFIG_FB */
static ssize_t lcd_show_power(struct class_device *cdev, char *buf)
{
int rc;
struct lcd_device *ld = to_lcd_device(cdev);
down(&ld->sem);
if (likely(ld->props && ld->props->get_power))
rc = sprintf(buf, "%d\n", ld->props->get_power(ld));
else
rc = -ENXIO;
up(&ld->sem);
return rc;
}
static ssize_t lcd_store_power(struct class_device *cdev, const char *buf, size_t count)
{
int rc = -ENXIO;
char *endp;
struct lcd_device *ld = to_lcd_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(&ld->sem);
if (likely(ld->props && ld->props->set_power)) {
pr_debug("lcd: set power to %d\n", power);
ld->props->set_power(ld, power);
rc = count;
}
up(&ld->sem);
return rc;
}
static ssize_t lcd_show_contrast(struct class_device *cdev, char *buf)
{
int rc = -ENXIO;
struct lcd_device *ld = to_lcd_device(cdev);
down(&ld->sem);
if (likely(ld->props && ld->props->get_contrast))
rc = sprintf(buf, "%d\n", ld->props->get_contrast(ld));
up(&ld->sem);
return rc;
}
static ssize_t lcd_store_contrast(struct class_device *cdev, const char *buf, size_t count)
{
int rc = -ENXIO;
char *endp;
struct lcd_device *ld = to_lcd_device(cdev);
int contrast = simple_strtoul(buf, &endp, 0);
size_t size = endp - buf;
if (*endp && isspace(*endp))
size++;
if (size != count)
return -EINVAL;
down(&ld->sem);
if (likely(ld->props && ld->props->set_contrast)) {
pr_debug("lcd: set contrast to %d\n", contrast);
ld->props->set_contrast(ld, contrast);
rc = count;
}
up(&ld->sem);
return rc;
}
static ssize_t lcd_show_max_contrast(struct class_device *cdev, char *buf)
{
int rc = -ENXIO;
struct lcd_device *ld = to_lcd_device(cdev);
down(&ld->sem);
if (likely(ld->props))
rc = sprintf(buf, "%d\n", ld->props->max_contrast);
up(&ld->sem);
return rc;
}
static void lcd_class_release(struct class_device *dev)
{
struct lcd_device *ld = to_lcd_device(dev);
kfree(ld);
}
static struct class lcd_class = {
.name = "lcd",
.release = lcd_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 lcd_class_device_attributes[] = {
DECLARE_ATTR(power, 0644, lcd_show_power, lcd_store_power),
DECLARE_ATTR(contrast, 0644, lcd_show_contrast, lcd_store_contrast),
DECLARE_ATTR(max_contrast, 0444, lcd_show_max_contrast, NULL),
};
/**
* lcd_device_register - register a new object of lcd_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(ld->class_dev).
* @lp: the lcd properties structure.
*
* Creates and registers a new lcd class_device. Returns either an ERR_PTR()
* or a pointer to the newly allocated device.
*/
struct lcd_device *lcd_device_register(const char *name, void *devdata,
struct lcd_properties *lp)
{
int i, rc;
struct lcd_device *new_ld;
pr_debug("lcd_device_register: name=%s\n", name);
new_ld = kmalloc(sizeof(struct lcd_device), GFP_KERNEL);
if (unlikely(!new_ld))
return ERR_PTR(-ENOMEM);
init_MUTEX(&new_ld->sem);
new_ld->props = lp;
memset(&new_ld->class_dev, 0, sizeof(new_ld->class_dev));
new_ld->class_dev.class = &lcd_class;
strlcpy(new_ld->class_dev.class_id, name, KOBJ_NAME_LEN);
class_set_devdata(&new_ld->class_dev, devdata);
rc = class_device_register(&new_ld->class_dev);
if (unlikely(rc)) {
error: kfree(new_ld);
return ERR_PTR(rc);
}
rc = lcd_register_fb(new_ld);
if (unlikely(rc))
goto error;
for (i = 0; i < ARRAY_SIZE(lcd_class_device_attributes); i++) {
rc = class_device_create_file(&new_ld->class_dev,
&lcd_class_device_attributes[i]);
if (unlikely(rc)) {
while (--i >= 0)
class_device_remove_file(&new_ld->class_dev,
&lcd_class_device_attributes[i]);
class_device_unregister(&new_ld->class_dev);
/* No need to kfree(new_ld) since release() method was called */
return ERR_PTR(rc);
}
}
return new_ld;
}
EXPORT_SYMBOL(lcd_device_register);
/**
* lcd_device_unregister - unregisters a object of lcd_device class.
* @ld: the lcd device object to be unregistered and freed.
*
* Unregisters a previously registered via lcd_device_register object.
*/
void lcd_device_unregister(struct lcd_device *ld)
{
int i;
if (!ld)
return;
pr_debug("lcd_device_unregister: name=%s\n", ld->class_dev.class_id);
for (i = 0; i < ARRAY_SIZE(lcd_class_device_attributes); i++)
class_device_remove_file(&ld->class_dev,
&lcd_class_device_attributes[i]);
down(&ld->sem);
ld->props = NULL;
up(&ld->sem);
lcd_unregister_fb(ld);
class_device_unregister(&ld->class_dev);
}
EXPORT_SYMBOL(lcd_device_unregister);
static void __exit lcd_class_exit(void)
{
class_unregister(&lcd_class);
}
static int __init lcd_class_init(void)
{
return class_register(&lcd_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(lcd_class_init);
module_exit(lcd_class_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Jamey Hicks <jamey.hicks@hp.com>, Andrew Zabolotny <zap@homelink.ru>");
MODULE_DESCRIPTION("LCD Lowlevel Control Abstraction");