/* SPDX-License-Identifier: GPL-2.0 */

  /*
   * LCD Lowlevel Control Abstraction
   *
   * Copyright (C) 2003,2004 Hewlett-Packard Company
   *
   */
  
  #ifndef _LINUX_LCD_H
  #define _LINUX_LCD_H
  
  #include <linux/device.h>

  #include <linux/mutex.h>

  #include <linux/notifier.h>

  #include <linux/fb.h>

  /* Notes on locking:
   *

   * lcd_device->ops_lock is an internal backlight lock protecting the ops

   * field and no code outside the core should need to touch it.
   *
   * Access to set_power() is serialised by the update_lock mutex since
   * most drivers seem to need this and historically get it wrong.
   *
   * Most drivers don't need locking on their get_power() method.
   * If yours does, you need to implement it in the driver. You can use the
   * update_lock mutex if appropriate.
   *
   * Any other use of the locks below is probably wrong.
   */

  struct lcd_device;
  struct fb_info;

  struct lcd_properties {

  	/* The maximum value for contrast (read-only) */
  	int max_contrast;
  };
  
  struct lcd_ops {

  	/* Get the LCD panel power status (0: full on, 1..3: controller
  	   power on, flat panel power off, 4: full off), see FB_BLANK_XXX */
  	int (*get_power)(struct lcd_device *);

  	/*
  	 * Enable or disable power to the LCD(0: on; 4: off, see FB_BLANK_XXX)
  	 * and this callback would be called proir to fb driver's callback.
  	 *
  	 * P.S. note that if early_set_power is not NULL then early fb notifier
  	 *	would be registered.
  	 */
  	int (*early_set_power)(struct lcd_device *, int power);
  	/* revert the effects of the early blank event. */
  	int (*r_early_set_power)(struct lcd_device *, int power);

  	/* Enable or disable power to the LCD (0: on; 4: off, see FB_BLANK_XXX) */
  	int (*set_power)(struct lcd_device *, int power);

  	/* Get the current contrast setting (0-max_contrast) */
  	int (*get_contrast)(struct lcd_device *);
  	/* Set LCD panel contrast */
          int (*set_contrast)(struct lcd_device *, int contrast);

  	/* Set LCD panel mode (resolutions ...) */
  	int (*set_mode)(struct lcd_device *, struct fb_videomode *);

  	/* Check if given framebuffer device is the one LCD is bound to;
  	   return 0 if not, !=0 if it is. If NULL, lcd always matches the fb. */

  	int (*check_fb)(struct lcd_device *, struct fb_info *);

  };
  
  struct lcd_device {

  	struct lcd_properties props;
  	/* This protects the 'ops' field. If 'ops' is NULL, the driver that

  	   registered this device has been unloaded, and if class_get_devdata()
  	   points to something in the body of that driver, it is also invalid. */

  	struct mutex ops_lock;

  	/* If this is NULL, the backing module is unloaded */

  	struct lcd_ops *ops;

  	/* Serialise access to set_power method */
  	struct mutex update_lock;

  	/* The framebuffer notifier block */
  	struct notifier_block fb_notif;

  
  	struct device dev;

  };

  struct lcd_platform_data {
  	/* reset lcd panel device. */
  	int (*reset)(struct lcd_device *ld);
  	/* on or off to lcd panel. if 'enable' is 0 then
  	   lcd power off and 1, lcd power on. */
  	int (*power_on)(struct lcd_device *ld, int enable);
  
  	/* it indicates whether lcd panel was enabled
  	   from bootloader or not. */
  	int lcd_enabled;
  	/* it means delay for stable time when it becomes low to high
  	   or high to low that is dependent on whether reset gpio is
  	   low active or high active. */
  	unsigned int reset_delay;
  	/* stable time needing to become lcd power on. */
  	unsigned int power_on_delay;
  	/* stable time needing to become lcd power off. */
  	unsigned int power_off_delay;
  
  	/* it could be used for any purpose. */
  	void *pdata;
  };

  static inline void lcd_set_power(struct lcd_device *ld, int power)
  {
  	mutex_lock(&ld->update_lock);

  	if (ld->ops && ld->ops->set_power)
  		ld->ops->set_power(ld, power);

  	mutex_unlock(&ld->update_lock);
  }

  extern struct lcd_device *lcd_device_register(const char *name,

  	struct device *parent, void *devdata, struct lcd_ops *ops);

  extern struct lcd_device *devm_lcd_device_register(struct device *dev,
  	const char *name, struct device *parent,
  	void *devdata, struct lcd_ops *ops);

  extern void lcd_device_unregister(struct lcd_device *ld);

  extern void devm_lcd_device_unregister(struct device *dev,
  	struct lcd_device *ld);

  #define to_lcd_device(obj) container_of(obj, struct lcd_device, dev)
  
  static inline void * lcd_get_data(struct lcd_device *ld_dev)
  {
  	return dev_get_drvdata(&ld_dev->dev);
  }

  
  #endif