/*
   * Backlight code for via-pmu
   *
   * Copyright (C) 1998 Paul Mackerras and Fabio Riccardi.
   * Copyright (C) 2001-2002 Benjamin Herrenschmidt
   * Copyright (C) 2006      Michael Hanselmann <linux-kernel@hansmi.ch>
   *
   */
  
  #include <asm/ptrace.h>
  #include <linux/adb.h>
  #include <linux/pmu.h>
  #include <asm/backlight.h>
  #include <asm/prom.h>
  
  #define MAX_PMU_LEVEL 0xFF

  static const struct backlight_ops pmu_backlight_data;

  static DEFINE_SPINLOCK(pmu_backlight_lock);

  static int sleeping, uses_pmu_bl;

  static u8 bl_curve[FB_BACKLIGHT_LEVELS];

  static void pmu_backlight_init_curve(u8 off, u8 min, u8 max)
  {

  	int i, flat, count, range = (max - min);

  
  	bl_curve[0] = off;
  
  	for (flat = 1; flat < (FB_BACKLIGHT_LEVELS / 16); ++flat)
  		bl_curve[flat] = min;
  
  	count = FB_BACKLIGHT_LEVELS * 15 / 16;
  	for (i = 0; i < count; ++i)
  		bl_curve[flat + i] = min + (range * (i + 1) / count);
  }
  
  static int pmu_backlight_curve_lookup(int value)
  {
  	int level = (FB_BACKLIGHT_LEVELS - 1);
  	int i, max = 0;
  
  	/* Look for biggest value */
  	for (i = 0; i < FB_BACKLIGHT_LEVELS; i++)
  		max = max((int)bl_curve[i], max);
  
  	/* Look for nearest value */
  	for (i = 0; i < FB_BACKLIGHT_LEVELS; i++) {
  		int diff = abs(bl_curve[i] - value);
  		if (diff < max) {
  			max = diff;
  			level = i;
  		}
  	}
  	return level;
  }
  
  static int pmu_backlight_get_level_brightness(int level)

  {
  	int pmulevel;
  
  	/* Get and convert the value */

  	pmulevel = bl_curve[level] * FB_BACKLIGHT_MAX / MAX_PMU_LEVEL;

  	if (pmulevel < 0)
  		pmulevel = 0;
  	else if (pmulevel > MAX_PMU_LEVEL)
  		pmulevel = MAX_PMU_LEVEL;
  
  	return pmulevel;
  }

  static int __pmu_backlight_update_status(struct backlight_device *bd)

  {

  	struct adb_request req;

  	int level = bd->props.brightness;

  	if (bd->props.power != FB_BLANK_UNBLANK ||
  	    bd->props.fb_blank != FB_BLANK_UNBLANK)

  		level = 0;

  	if (level > 0) {

  		int pmulevel = pmu_backlight_get_level_brightness(level);

  		pmu_request(&req, NULL, 2, PMU_BACKLIGHT_BRIGHT, pmulevel);
  		pmu_wait_complete(&req);

  		pmu_request(&req, NULL, 2, PMU_POWER_CTRL,
  			PMU_POW_BACKLIGHT | PMU_POW_ON);
  		pmu_wait_complete(&req);
  	} else {
  		pmu_request(&req, NULL, 2, PMU_POWER_CTRL,
  			PMU_POW_BACKLIGHT | PMU_POW_OFF);
  		pmu_wait_complete(&req);
  	}

  	return 0;
  }

  static int pmu_backlight_update_status(struct backlight_device *bd)
  {
  	unsigned long flags;
  	int rc = 0;
  
  	spin_lock_irqsave(&pmu_backlight_lock, flags);
  	/* Don't update brightness when sleeping */
  	if (!sleeping)
  		rc = __pmu_backlight_update_status(bd);
  	spin_unlock_irqrestore(&pmu_backlight_lock, flags);
  	return rc;
  }

  static int pmu_backlight_get_brightness(struct backlight_device *bd)
  {

  	return bd->props.brightness;

  }

  static const struct backlight_ops pmu_backlight_data = {

  	.get_brightness	= pmu_backlight_get_brightness,
  	.update_status	= pmu_backlight_update_status,

  };

  #ifdef CONFIG_PM

  void pmu_backlight_set_sleep(int sleep)

  {
  	unsigned long flags;
  
  	spin_lock_irqsave(&pmu_backlight_lock, flags);

  	sleeping = sleep;

  	if (pmac_backlight && uses_pmu_bl) {

  		if (sleep) {
  			struct adb_request req;
  
  			pmu_request(&req, NULL, 2, PMU_POWER_CTRL,
  				    PMU_POW_BACKLIGHT | PMU_POW_OFF);
  			pmu_wait_complete(&req);
  		} else
  			__pmu_backlight_update_status(pmac_backlight);
  	}

  	spin_unlock_irqrestore(&pmu_backlight_lock, flags);

  }

  #endif /* CONFIG_PM */

  
  void __init pmu_backlight_init()

  {

  	struct backlight_properties props;

  	struct backlight_device *bd;

  	char name[10];
  	int level, autosave;

  	/* Special case for the old PowerBook since I can't test on it */
  	autosave =

  		of_machine_is_compatible("AAPL,3400/2400") ||
  		of_machine_is_compatible("AAPL,3500");

  
  	if (!autosave &&
  	    !pmac_has_backlight_type("pmu") &&

  	    !of_machine_is_compatible("AAPL,PowerBook1998") &&
  	    !of_machine_is_compatible("PowerBook1,1"))

  		return;

  	snprintf(name, sizeof(name), "pmubl");

  	memset(&props, 0, sizeof(struct backlight_properties));

  	props.type = BACKLIGHT_PLATFORM;

  	props.max_brightness = FB_BACKLIGHT_LEVELS - 1;
  	bd = backlight_device_register(name, NULL, NULL, &pmu_backlight_data,
  				       &props);

  	if (IS_ERR(bd)) {

  		printk(KERN_ERR "PMU Backlight registration failed
  ");
  		return;

  	}

  	uses_pmu_bl = 1;

  	pmu_backlight_init_curve(0x7F, 0x46, 0x0E);

  	level = bd->props.max_brightness;

  
  	if (autosave) {
  		/* read autosaved value if available */
  		struct adb_request req;
  		pmu_request(&req, NULL, 2, 0xd9, 0);
  		pmu_wait_complete(&req);

  		level = pmu_backlight_curve_lookup(

  				(req.reply[0] >> 4) *

  				bd->props.max_brightness / 15);

  	}

  	bd->props.brightness = level;
  	bd->props.power = FB_BLANK_UNBLANK;

  	backlight_update_status(bd);

  	printk(KERN_INFO "PMU Backlight initialized (%s)
  ", name);

  }