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