| // SPDX-License-Identifier: GPL-2.0-only |
| /* |
| * LCD 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/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) |
| { |
| struct lcd_device *ld; |
| struct fb_event *evdata = data; |
| |
| ld = container_of(self, struct lcd_device, fb_notif); |
| if (!ld->ops) |
| return 0; |
| |
| mutex_lock(&ld->ops_lock); |
| if (!ld->ops->check_fb || ld->ops->check_fb(ld, evdata->info)) { |
| if (event == FB_EVENT_BLANK) { |
| if (ld->ops->set_power) |
| ld->ops->set_power(ld, *(int *)evdata->data); |
| } else { |
| if (ld->ops->set_mode) |
| ld->ops->set_mode(ld, 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_power_show(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_power_store(struct device *dev, |
| struct device_attribute *attr, const char *buf, size_t count) |
| { |
| int rc; |
| struct lcd_device *ld = to_lcd_device(dev); |
| unsigned long power; |
| |
| rc = kstrtoul(buf, 0, &power); |
| if (rc) |
| return rc; |
| |
| rc = -ENXIO; |
| |
| mutex_lock(&ld->ops_lock); |
| if (ld->ops && ld->ops->set_power) { |
| pr_debug("set power to %lu\n", power); |
| ld->ops->set_power(ld, power); |
| rc = count; |
| } |
| mutex_unlock(&ld->ops_lock); |
| |
| return rc; |
| } |
| static DEVICE_ATTR_RW(lcd_power); |
| |
| static ssize_t contrast_show(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 contrast_store(struct device *dev, |
| struct device_attribute *attr, const char *buf, size_t count) |
| { |
| int rc; |
| struct lcd_device *ld = to_lcd_device(dev); |
| unsigned long contrast; |
| |
| rc = kstrtoul(buf, 0, &contrast); |
| if (rc) |
| return rc; |
| |
| rc = -ENXIO; |
| |
| mutex_lock(&ld->ops_lock); |
| if (ld->ops && ld->ops->set_contrast) { |
| pr_debug("set contrast to %lu\n", contrast); |
| ld->ops->set_contrast(ld, contrast); |
| rc = count; |
| } |
| mutex_unlock(&ld->ops_lock); |
| |
| return rc; |
| } |
| static DEVICE_ATTR_RW(contrast); |
| |
| static ssize_t max_contrast_show(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 DEVICE_ATTR_RO(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 attribute *lcd_device_attrs[] = { |
| &dev_attr_lcd_power.attr, |
| &dev_attr_contrast.attr, |
| &dev_attr_max_contrast.attr, |
| NULL, |
| }; |
| ATTRIBUTE_GROUPS(lcd_device); |
| |
| /** |
| * 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, 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; |
| dev_set_name(&new_ld->dev, "%s", name); |
| dev_set_drvdata(&new_ld->dev, devdata); |
| |
| new_ld->ops = ops; |
| |
| rc = device_register(&new_ld->dev); |
| if (rc) { |
| put_device(&new_ld->dev); |
| return ERR_PTR(rc); |
| } |
| |
| rc = lcd_register_fb(new_ld); |
| if (rc) { |
| device_unregister(&new_ld->dev); |
| 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) |
| { |
| 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 devm_lcd_device_release(struct device *dev, void *res) |
| { |
| struct lcd_device *lcd = *(struct lcd_device **)res; |
| |
| lcd_device_unregister(lcd); |
| } |
| |
| static int devm_lcd_device_match(struct device *dev, void *res, void *data) |
| { |
| struct lcd_device **r = res; |
| |
| return *r == 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, struct lcd_ops *ops) |
| { |
| struct lcd_device **ptr, *lcd; |
| |
| ptr = devres_alloc(devm_lcd_device_release, sizeof(*ptr), GFP_KERNEL); |
| if (!ptr) |
| return ERR_PTR(-ENOMEM); |
| |
| lcd = lcd_device_register(name, parent, devdata, ops); |
| if (!IS_ERR(lcd)) { |
| *ptr = lcd; |
| devres_add(dev, ptr); |
| } else { |
| devres_free(ptr); |
| } |
| |
| return lcd; |
| } |
| EXPORT_SYMBOL(devm_lcd_device_register); |
| |
| /** |
| * 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) |
| { |
| int rc; |
| |
| rc = devres_release(dev, devm_lcd_device_release, |
| devm_lcd_device_match, ld); |
| WARN_ON(rc); |
| } |
| EXPORT_SYMBOL(devm_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)) { |
| pr_warn("Unable to create backlight class; errno = %ld\n", |
| PTR_ERR(lcd_class)); |
| return PTR_ERR(lcd_class); |
| } |
| |
| lcd_class->dev_groups = lcd_device_groups; |
| 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"); |