/* * 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); mutex_lock(&ld->ops_lock); if (ld->ops) if (!ld->ops->check_fb || ld->ops->check_fb(ld, evdata->info)) ld->ops->set_power(ld, *(int *)evdata->data); mutex_unlock(&ld->ops_lock); 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 device *dev, struct device_attribute *attr, char *buf) { int rc; struct lcd_device *ld = to_lcd_device(dev); mutex_lock(&ld->ops_lock); if (ld->ops && ld->ops->get_power) rc = sprintf(buf, "%d\n", ld->ops->get_power(ld)); else rc = -ENXIO; mutex_unlock(&ld->ops_lock); return rc; } static ssize_t lcd_store_power(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) { int rc = -ENXIO; char *endp; struct lcd_device *ld = to_lcd_device(dev); int power = simple_strtoul(buf, &endp, 0); size_t size = endp - buf; if (*endp && isspace(*endp)) size++; if (size != count) return -EINVAL; mutex_lock(&ld->ops_lock); if (ld->ops && ld->ops->set_power) { pr_debug("lcd: set power to %d\n", power); ld->ops->set_power(ld, power); rc = count; } mutex_unlock(&ld->ops_lock); return rc; } static ssize_t lcd_show_contrast(struct device *dev, struct device_attribute *attr, char *buf) { int rc = -ENXIO; struct lcd_device *ld = to_lcd_device(dev); mutex_lock(&ld->ops_lock); if (ld->ops && ld->ops->get_contrast) rc = sprintf(buf, "%d\n", ld->ops->get_contrast(ld)); mutex_unlock(&ld->ops_lock); return rc; } static ssize_t lcd_store_contrast(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) { int rc = -ENXIO; char *endp; struct lcd_device *ld = to_lcd_device(dev); int contrast = simple_strtoul(buf, &endp, 0); size_t size = endp - buf; if (*endp && isspace(*endp)) size++; if (size != count) return -EINVAL; mutex_lock(&ld->ops_lock); if (ld->ops && ld->ops->set_contrast) { pr_debug("lcd: set contrast to %d\n", contrast); ld->ops->set_contrast(ld, contrast); rc = count; } mutex_unlock(&ld->ops_lock); return rc; } static ssize_t lcd_show_max_contrast(struct device *dev, struct device_attribute *attr, char *buf) { struct lcd_device *ld = to_lcd_device(dev); return sprintf(buf, "%d\n", ld->props.max_contrast); } static struct class *lcd_class; static void lcd_device_release(struct device *dev) { struct lcd_device *ld = to_lcd_device(dev); kfree(ld); } static struct device_attribute lcd_device_attributes[] = { __ATTR(lcd_power, 0644, lcd_show_power, lcd_store_power), __ATTR(contrast, 0644, lcd_show_contrast, lcd_store_contrast), __ATTR(max_contrast, 0444, lcd_show_max_contrast, NULL), __ATTR_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 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, struct lcd_ops *ops) { struct lcd_device *new_ld; int rc; pr_debug("lcd_device_register: name=%s\n", name); new_ld = kzalloc(sizeof(struct lcd_device), GFP_KERNEL); if (!new_ld) return ERR_PTR(-ENOMEM); mutex_init(&new_ld->ops_lock); mutex_init(&new_ld->update_lock); new_ld->dev.class = lcd_class; new_ld->dev.parent = parent; new_ld->dev.release = lcd_device_release; strlcpy(new_ld->dev.bus_id, name, BUS_ID_SIZE); dev_set_drvdata(&new_ld->dev, devdata); rc = device_register(&new_ld->dev); if (rc) { kfree(new_ld); return ERR_PTR(rc); } rc = lcd_register_fb(new_ld); if (rc) { device_unregister(&new_ld->dev); return ERR_PTR(rc); } new_ld->ops = ops; 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) { if (!ld) return; mutex_lock(&ld->ops_lock); ld->ops = NULL; mutex_unlock(&ld->ops_lock); lcd_unregister_fb(ld); device_unregister(&ld->dev); } EXPORT_SYMBOL(lcd_device_unregister); static void __exit lcd_class_exit(void) { class_destroy(lcd_class); } static int __init lcd_class_init(void) { lcd_class = class_create(THIS_MODULE, "lcd"); if (IS_ERR(lcd_class)) { printk(KERN_WARNING "Unable to create backlight class; errno = %ld\n", PTR_ERR(lcd_class)); return PTR_ERR(lcd_class); } lcd_class->dev_attrs = lcd_device_attributes; return 0; } /* * 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");