1 files changed, 346 insertions, 0 deletions
diff --git a/drivers/video/backlight/lcd.c b/drivers/video/backlight/lcd.c
new file mode 100644
index 0000000000..77c5cb2a44
--- /dev/null
+++ b/drivers/video/backlight/lcd.c
@@ -0,0 +1,346 @@
+// 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("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");