linux/drivers/video/backlight/lcd.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * LCD Lowlevel Control Abstraction
 *
 * Copyright (C) 2003,2004 Hewlett-Packard Company
 *
 */

#define pr_fmt(fmt) …

#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>
#include <linux/slab.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)
{ … }

static int lcd_register_fb(struct lcd_device *ld)
{ … }

static void lcd_unregister_fb(struct lcd_device *ld)
{ … }
#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_power_show(struct device *dev, struct device_attribute *attr,
		char *buf)
{ … }

static ssize_t lcd_power_store(struct device *dev,
		struct device_attribute *attr, const char *buf, size_t count)
{ … }
static DEVICE_ATTR_RW(lcd_power);

static ssize_t contrast_show(struct device *dev,
		struct device_attribute *attr, char *buf)
{ … }

static ssize_t contrast_store(struct device *dev,
		struct device_attribute *attr, const char *buf, size_t count)
{ … }
static DEVICE_ATTR_RW(contrast);

static ssize_t max_contrast_show(struct device *dev,
		struct device_attribute *attr, char *buf)
{ … }
static DEVICE_ATTR_RO(max_contrast);

static void lcd_device_release(struct device *dev)
{ … }

static struct attribute *lcd_device_attrs[] = …;
ATTRIBUTE_GROUPS(…);

static const struct class lcd_class = …;

/**
 * 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).
 * @parent: pointer to the parent's struct device .
 * @devdata: an optional pointer to be stored in the device. The
 *   methods may retrieve it by using lcd_get_data(ld).
 * @ops: the lcd operations structure.
 *
 * Creates and registers a new lcd device. Returns either an ERR_PTR()
 * or a pointer to the newly allocated device.
 */
struct lcd_device *lcd_device_register(const char *name, struct device *parent,
		void *devdata, const struct lcd_ops *ops)
{ … }
EXPORT_SYMBOL(…);

/**
 * 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)
{ … }
EXPORT_SYMBOL(…);

static void devm_lcd_device_release(struct device *dev, void *res)
{ … }

static int devm_lcd_device_match(struct device *dev, void *res, void *data)
{ … }

/**
 * devm_lcd_device_register - resource managed lcd_device_register()
 * @dev: the device to register
 * @name: the name of the device
 * @parent: a pointer to the parent device
 * @devdata: an optional pointer to be stored for private driver use
 * @ops: the lcd operations structure
 *
 * @return a struct lcd on success, or an ERR_PTR on error
 *
 * Managed lcd_device_register(). The lcd_device returned from this function
 * are automatically freed on driver detach. See lcd_device_register()
 * for more information.
 */
struct lcd_device *devm_lcd_device_register(struct device *dev,
		const char *name, struct device *parent,
		void *devdata, const struct lcd_ops *ops)
{ … }
EXPORT_SYMBOL(…);

/**
 * devm_lcd_device_unregister - resource managed lcd_device_unregister()
 * @dev: the device to unregister
 * @ld: the lcd device to unregister
 *
 * Deallocated a lcd allocated with devm_lcd_device_register(). Normally
 * this function will not need to be called and the resource management
 * code will ensure that the resource is freed.
 */
void devm_lcd_device_unregister(struct device *dev, struct lcd_device *ld)
{ … }
EXPORT_SYMBOL(…);


static void __exit lcd_class_exit(void)
{ … }

static int __init lcd_class_init(void)
{ … }

/*
 * 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(…) …;
MODULE_AUTHOR(…) …;
MODULE_DESCRIPTION(…) …;