/* * Backlight Lowlevel Control Abstraction * * Copyright (C) 2003,2004 Hewlett-Packard Company * */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #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> #include <linux/slab.h> #ifdef CONFIG_PMAC_BACKLIGHT #include <asm/backlight.h> #endif static struct list_head backlight_dev_list; static struct mutex backlight_dev_list_mutex; static struct blocking_notifier_head backlight_notifier; static const char *const backlight_types[] = { [BACKLIGHT_RAW] = "raw", [BACKLIGHT_PLATFORM] = "platform", [BACKLIGHT_FIRMWARE] = "firmware", }; #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 and necessary, 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; int node = evdata->info->node; int fb_blank = 0; /* 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(bd, evdata->info)) { fb_blank = *(int *)evdata->data; if (fb_blank == FB_BLANK_UNBLANK && !bd->fb_bl_on[node]) { bd->fb_bl_on[node] = true; if (!bd->use_count++) { bd->props.state &= ~BL_CORE_FBBLANK; bd->props.fb_blank = FB_BLANK_UNBLANK; backlight_update_status(bd); } } else if (fb_blank != FB_BLANK_UNBLANK && bd->fb_bl_on[node]) { bd->fb_bl_on[node] = false; if (!(--bd->use_count)) { bd->props.state |= BL_CORE_FBBLANK; bd->props.fb_blank = fb_blank; 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 void backlight_generate_event(struct backlight_device *bd, enum backlight_update_reason reason) { char *envp[2]; switch (reason) { case BACKLIGHT_UPDATE_SYSFS: envp[0] = "SOURCE=sysfs"; break; case BACKLIGHT_UPDATE_HOTKEY: envp[0] = "SOURCE=hotkey"; break; default: envp[0] = "SOURCE=unknown"; break; } envp[1] = NULL; kobject_uevent_env(&bd->dev.kobj, KOBJ_CHANGE, envp); sysfs_notify(&bd->dev.kobj, NULL, "actual_brightness"); } static ssize_t bl_power_show(struct device *dev, struct device_attribute *attr, char *buf) { struct backlight_device *bd = to_backlight_device(dev); return sprintf(buf, "%d\n", bd->props.power); } static ssize_t bl_power_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) { int rc; struct backlight_device *bd = to_backlight_device(dev); unsigned long power; rc = kstrtoul(buf, 0, &power); if (rc) return rc; rc = -ENXIO; mutex_lock(&bd->ops_lock); if (bd->ops) { pr_debug("set power to %lu\n", power); if (bd->props.power != power) { bd->props.power = power; backlight_update_status(bd); } rc = count; } mutex_unlock(&bd->ops_lock); return rc; } static DEVICE_ATTR_RW(bl_power); static ssize_t brightness_show(struct device *dev, struct device_attribute *attr, char *buf) { struct backlight_device *bd = to_backlight_device(dev); return sprintf(buf, "%d\n", bd->props.brightness); } int backlight_device_set_brightness(struct backlight_device *bd, unsigned long brightness) { int rc = -ENXIO; mutex_lock(&bd->ops_lock); if (bd->ops) { if (brightness > bd->props.max_brightness) rc = -EINVAL; else { pr_debug("set brightness to %lu\n", brightness); bd->props.brightness = brightness; backlight_update_status(bd); rc = 0; } } mutex_unlock(&bd->ops_lock); backlight_generate_event(bd, BACKLIGHT_UPDATE_SYSFS); return rc; } EXPORT_SYMBOL(backlight_device_set_brightness); static ssize_t brightness_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) { int rc; struct backlight_device *bd = to_backlight_device(dev); unsigned long brightness; rc = kstrtoul(buf, 0, &brightness); if (rc) return rc; rc = backlight_device_set_brightness(bd, brightness); return rc ? rc : count; } static DEVICE_ATTR_RW(brightness); static ssize_t type_show(struct device *dev, struct device_attribute *attr, char *buf) { struct backlight_device *bd = to_backlight_device(dev); return sprintf(buf, "%s\n", backlight_types[bd->props.type]); } static DEVICE_ATTR_RO(type); static ssize_t max_brightness_show(struct device *dev, struct device_attribute *attr, char *buf) { struct backlight_device *bd = to_backlight_device(dev); return sprintf(buf, "%d\n", bd->props.max_brightness); } static DEVICE_ATTR_RO(max_brightness); static ssize_t actual_brightness_show(struct device *dev, struct device_attribute *attr, char *buf) { int rc = -ENXIO; struct backlight_device *bd = to_backlight_device(dev); mutex_lock(&bd->ops_lock); if (bd->ops && bd->ops->get_brightness) rc = sprintf(buf, "%d\n", bd->ops->get_brightness(bd)); else rc = sprintf(buf, "%d\n", bd->props.brightness); mutex_unlock(&bd->ops_lock); return rc; } static DEVICE_ATTR_RO(actual_brightness); static struct class *backlight_class; #ifdef CONFIG_PM_SLEEP static int backlight_suspend(struct device *dev) { struct backlight_device *bd = to_backlight_device(dev); mutex_lock(&bd->ops_lock); if (bd->ops && bd->ops->options & BL_CORE_SUSPENDRESUME) { bd->props.state |= BL_CORE_SUSPENDED; backlight_update_status(bd); } mutex_unlock(&bd->ops_lock); return 0; } static int backlight_resume(struct device *dev) { struct backlight_device *bd = to_backlight_device(dev); mutex_lock(&bd->ops_lock); if (bd->ops && bd->ops->options & BL_CORE_SUSPENDRESUME) { bd->props.state &= ~BL_CORE_SUSPENDED; backlight_update_status(bd); } mutex_unlock(&bd->ops_lock); return 0; } #endif static SIMPLE_DEV_PM_OPS(backlight_class_dev_pm_ops, backlight_suspend, backlight_resume); static void bl_device_release(struct device *dev) { struct backlight_device *bd = to_backlight_device(dev); kfree(bd); } static struct attribute *bl_device_attrs[] = { &dev_attr_bl_power.attr, &dev_attr_brightness.attr, &dev_attr_actual_brightness.attr, &dev_attr_max_brightness.attr, &dev_attr_type.attr, NULL, }; ATTRIBUTE_GROUPS(bl_device); /** * backlight_force_update - tell the backlight subsystem that hardware state * has changed * @bd: the backlight device to update * * Updates the internal state of the backlight in response to a hardware event, * and generate a uevent to notify userspace */ void backlight_force_update(struct backlight_device *bd, enum backlight_update_reason reason) { mutex_lock(&bd->ops_lock); if (bd->ops && bd->ops->get_brightness) bd->props.brightness = bd->ops->get_brightness(bd); mutex_unlock(&bd->ops_lock); backlight_generate_event(bd, reason); } EXPORT_SYMBOL(backlight_force_update); /** * 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). * @parent: a pointer to the parent device * @devdata: an optional pointer to be stored for private driver use. The * methods may retrieve it by using bl_get_data(bd). * @ops: the backlight operations structure. * * Creates and registers new backlight 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 *parent, void *devdata, const struct backlight_ops *ops, const struct backlight_properties *props) { struct backlight_device *new_bd; int rc; pr_debug("backlight_device_register: 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->dev.class = backlight_class; new_bd->dev.parent = parent; new_bd->dev.release = bl_device_release; dev_set_name(&new_bd->dev, "%s", name); dev_set_drvdata(&new_bd->dev, devdata); /* Set default properties */ if (props) { memcpy(&new_bd->props, props, sizeof(struct backlight_properties)); if (props->type <= 0 || props->type >= BACKLIGHT_TYPE_MAX) { WARN(1, "%s: invalid backlight type", name); new_bd->props.type = BACKLIGHT_RAW; } } else { new_bd->props.type = BACKLIGHT_RAW; } rc = device_register(&new_bd->dev); if (rc) { put_device(&new_bd->dev); return ERR_PTR(rc); } rc = backlight_register_fb(new_bd); if (rc) { device_unregister(&new_bd->dev); return ERR_PTR(rc); } new_bd->ops = ops; #ifdef CONFIG_PMAC_BACKLIGHT mutex_lock(&pmac_backlight_mutex); if (!pmac_backlight) pmac_backlight = new_bd; mutex_unlock(&pmac_backlight_mutex); #endif mutex_lock(&backlight_dev_list_mutex); list_add(&new_bd->entry, &backlight_dev_list); mutex_unlock(&backlight_dev_list_mutex); blocking_notifier_call_chain(&backlight_notifier, BACKLIGHT_REGISTERED, new_bd); return new_bd; } EXPORT_SYMBOL(backlight_device_register); struct backlight_device *backlight_device_get_by_type(enum backlight_type type) { bool found = false; struct backlight_device *bd; mutex_lock(&backlight_dev_list_mutex); list_for_each_entry(bd, &backlight_dev_list, entry) { if (bd->props.type == type) { found = true; break; } } mutex_unlock(&backlight_dev_list_mutex); return found ? bd : NULL; } EXPORT_SYMBOL(backlight_device_get_by_type); /** * 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) { if (!bd) return; mutex_lock(&backlight_dev_list_mutex); list_del(&bd->entry); mutex_unlock(&backlight_dev_list_mutex); #ifdef CONFIG_PMAC_BACKLIGHT mutex_lock(&pmac_backlight_mutex); if (pmac_backlight == bd) pmac_backlight = NULL; mutex_unlock(&pmac_backlight_mutex); #endif blocking_notifier_call_chain(&backlight_notifier, BACKLIGHT_UNREGISTERED, bd); mutex_lock(&bd->ops_lock); bd->ops = NULL; mutex_unlock(&bd->ops_lock); backlight_unregister_fb(bd); device_unregister(&bd->dev); } EXPORT_SYMBOL(backlight_device_unregister); static void devm_backlight_device_release(struct device *dev, void *res) { struct backlight_device *backlight = *(struct backlight_device **)res; backlight_device_unregister(backlight); } static int devm_backlight_device_match(struct device *dev, void *res, void *data) { struct backlight_device **r = res; return *r == data; } /** * backlight_register_notifier - get notified of backlight (un)registration * @nb: notifier block with the notifier to call on backlight (un)registration * * @return 0 on success, otherwise a negative error code * * Register a notifier to get notified when backlight devices get registered * or unregistered. */ int backlight_register_notifier(struct notifier_block *nb) { return blocking_notifier_chain_register(&backlight_notifier, nb); } EXPORT_SYMBOL(backlight_register_notifier); /** * backlight_unregister_notifier - unregister a backlight notifier * @nb: notifier block to unregister * * @return 0 on success, otherwise a negative error code * * Register a notifier to get notified when backlight devices get registered * or unregistered. */ int backlight_unregister_notifier(struct notifier_block *nb) { return blocking_notifier_chain_unregister(&backlight_notifier, nb); } EXPORT_SYMBOL(backlight_unregister_notifier); /** * devm_backlight_device_register - resource managed backlight_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 backlight operations structure * @props: the backlight properties * * @return a struct backlight on success, or an ERR_PTR on error * * Managed backlight_device_register(). The backlight_device returned * from this function are automatically freed on driver detach. * See backlight_device_register() for more information. */ struct backlight_device *devm_backlight_device_register(struct device *dev, const char *name, struct device *parent, void *devdata, const struct backlight_ops *ops, const struct backlight_properties *props) { struct backlight_device **ptr, *backlight; ptr = devres_alloc(devm_backlight_device_release, sizeof(*ptr), GFP_KERNEL); if (!ptr) return ERR_PTR(-ENOMEM); backlight = backlight_device_register(name, parent, devdata, ops, props); if (!IS_ERR(backlight)) { *ptr = backlight; devres_add(dev, ptr); } else { devres_free(ptr); } return backlight; } EXPORT_SYMBOL(devm_backlight_device_register); /** * devm_backlight_device_unregister - resource managed backlight_device_unregister() * @dev: the device to unregister * @bd: the backlight device to unregister * * Deallocated a backlight allocated with devm_backlight_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_backlight_device_unregister(struct device *dev, struct backlight_device *bd) { int rc; rc = devres_release(dev, devm_backlight_device_release, devm_backlight_device_match, bd); WARN_ON(rc); } EXPORT_SYMBOL(devm_backlight_device_unregister); #ifdef CONFIG_OF static int of_parent_match(struct device *dev, const void *data) { return dev->parent && dev->parent->of_node == data; } /** * of_find_backlight_by_node() - find backlight device by device-tree node * @node: device-tree node of the backlight device * * Returns a pointer to the backlight device corresponding to the given DT * node or NULL if no such backlight device exists or if the device hasn't * been probed yet. * * This function obtains a reference on the backlight device and it is the * caller's responsibility to drop the reference by calling put_device() on * the backlight device's .dev field. */ struct backlight_device *of_find_backlight_by_node(struct device_node *node) { struct device *dev; dev = class_find_device(backlight_class, NULL, node, of_parent_match); return dev ? to_backlight_device(dev) : NULL; } EXPORT_SYMBOL(of_find_backlight_by_node); #endif static void __exit backlight_class_exit(void) { class_destroy(backlight_class); } static int __init backlight_class_init(void) { backlight_class = class_create(THIS_MODULE, "backlight"); if (IS_ERR(backlight_class)) { pr_warn("Unable to create backlight class; errno = %ld\n", PTR_ERR(backlight_class)); return PTR_ERR(backlight_class); } backlight_class->dev_groups = bl_device_groups; backlight_class->pm = &backlight_class_dev_pm_ops; INIT_LIST_HEAD(&backlight_dev_list); mutex_init(&backlight_dev_list_mutex); BLOCKING_INIT_NOTIFIER_HEAD(&backlight_notifier); 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(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");