drivers/macintosh/via-pmu-backlight.c

   1 /*
   2  * Backlight code for via-pmu
   3  *
   4  * Copyright (C) 1998 Paul Mackerras and Fabio Riccardi.
   5  * Copyright (C) 2001-2002 Benjamin Herrenschmidt
   6  * Copyright (C) 2006      Michael Hanselmann <linux-kernel@hansmi.ch>
   7  *
   8  */
   9
  10 #include <asm/ptrace.h>
  11 #include <linux/adb.h>
  12 #include <linux/pmu.h>
  13 #include <asm/backlight.h>
  14 #include <asm/prom.h>
  15
  16 #define MAX_PMU_LEVEL 0xFF
  17
  18 static struct backlight_ops pmu_backlight_data;
  19 static DEFINE_SPINLOCK(pmu_backlight_lock);
  20 static int sleeping;
  21 static u8 bl_curve[FB_BACKLIGHT_LEVELS];
  22
  23 static void pmu_backlight_init_curve(u8 off, u8 min, u8 max)
  24 {
  25         unsigned int i, flat, count, range = (max - min);
  26
  27         bl_curve[0] = off;
  28
  29         for (flat = 1; flat < (FB_BACKLIGHT_LEVELS / 16); ++flat)
  30                 bl_curve[flat] = min;
  31
  32         count = FB_BACKLIGHT_LEVELS * 15 / 16;
  33         for (i = 0; i < count; ++i)
  34                 bl_curve[flat + i] = min + (range * (i + 1) / count);
  35 }
  36
  37 static int pmu_backlight_curve_lookup(int value)
  38 {
  39         int level = (FB_BACKLIGHT_LEVELS - 1);
  40         int i, max = 0;
  41
  42         /* Look for biggest value */
  43         for (i = 0; i < FB_BACKLIGHT_LEVELS; i++)
  44                 max = max((int)bl_curve[i], max);
  45
  46         /* Look for nearest value */
  47         for (i = 0; i < FB_BACKLIGHT_LEVELS; i++) {
  48                 int diff = abs(bl_curve[i] - value);
  49                 if (diff < max) {
  50                         max = diff;
  51                         level = i;
  52                 }
  53         }
  54         return level;
  55 }
  56
  57 static int pmu_backlight_get_level_brightness(int level)
  58 {
  59         int pmulevel;
  60
  61         /* Get and convert the value */
  62         pmulevel = bl_curve[level] * FB_BACKLIGHT_MAX / MAX_PMU_LEVEL;
  63         if (pmulevel < 0)
  64                 pmulevel = 0;
  65         else if (pmulevel > MAX_PMU_LEVEL)
  66                 pmulevel = MAX_PMU_LEVEL;
  67
  68         return pmulevel;
  69 }
  70
  71 static int pmu_backlight_update_status(struct backlight_device *bd)
  72 {
  73         struct adb_request req;
  74         unsigned long flags;
  75         int level = bd->props.brightness;
  76
  77         spin_lock_irqsave(&pmu_backlight_lock, flags);
  78
  79         /* Don't update brightness when sleeping */
  80         if (sleeping)
  81                 goto out;
  82
  83         if (bd->props.power != FB_BLANK_UNBLANK ||
  84             bd->props.fb_blank != FB_BLANK_UNBLANK)
  85                 level = 0;
  86
  87         if (level > 0) {
  88                 int pmulevel = pmu_backlight_get_level_brightness(level);
  89
  90                 pmu_request(&req, NULL, 2, PMU_BACKLIGHT_BRIGHT, pmulevel);
  91                 pmu_wait_complete(&req);
  92
  93                 pmu_request(&req, NULL, 2, PMU_POWER_CTRL,
  94                         PMU_POW_BACKLIGHT | PMU_POW_ON);
  95                 pmu_wait_complete(&req);
  96         } else {
  97                 pmu_request(&req, NULL, 2, PMU_POWER_CTRL,
  98                         PMU_POW_BACKLIGHT | PMU_POW_OFF);
  99                 pmu_wait_complete(&req);
 100         }
 101
 102 out:
 103         spin_unlock_irqrestore(&pmu_backlight_lock, flags);
 104
 105         return 0;
 106 }
 107
 108 static int pmu_backlight_get_brightness(struct backlight_device *bd)
 109 {
 110         return bd->props.brightness;
 111 }
 112
 113 static struct backlight_ops pmu_backlight_data = {
 114         .get_brightness = pmu_backlight_get_brightness,
 115         .update_status  = pmu_backlight_update_status,
 116
 117 };
 118
 119 #ifdef CONFIG_PM
 120 void pmu_backlight_set_sleep(int sleep)
 121 {
 122         unsigned long flags;
 123
 124         spin_lock_irqsave(&pmu_backlight_lock, flags);
 125         sleeping = sleep;
 126         spin_unlock_irqrestore(&pmu_backlight_lock, flags);
 127 }
 128 #endif /* CONFIG_PM */
 129
 130 void __init pmu_backlight_init()
 131 {
 132         struct backlight_device *bd;
 133         char name[10];
 134         int level, autosave;
 135
 136         /* Special case for the old PowerBook since I can't test on it */
 137         autosave =
 138                 machine_is_compatible("AAPL,3400/2400") ||
 139                 machine_is_compatible("AAPL,3500");
 140
 141         if (!autosave &&
 142             !pmac_has_backlight_type("pmu") &&
 143             !machine_is_compatible("AAPL,PowerBook1998") &&
 144             !machine_is_compatible("PowerBook1,1"))
 145                 return;
 146
 147         snprintf(name, sizeof(name), "pmubl");
 148
 149         bd = backlight_device_register(name, NULL, NULL, &pmu_backlight_data);
 150         if (IS_ERR(bd)) {
 151                 printk("pmubl: Backlight registration failed\n");
 152                 goto error;
 153         }
 154         bd->props.max_brightness = FB_BACKLIGHT_LEVELS - 1;
 155         pmu_backlight_init_curve(0x7F, 0x46, 0x0E);
 156
 157         level = bd->props.max_brightness;
 158
 159         if (autosave) {
 160                 /* read autosaved value if available */
 161                 struct adb_request req;
 162                 pmu_request(&req, NULL, 2, 0xd9, 0);
 163                 pmu_wait_complete(&req);
 164
 165                 level = pmu_backlight_curve_lookup(
 166                                 (req.reply[0] >> 4) *
 167                                 bd->props.max_brightness / 15);
 168         }
 169
 170         bd->props.brightness = level;
 171         bd->props.power = FB_BLANK_UNBLANK;
 172         backlight_update_status(bd);
 173
 174         printk("pmubl: Backlight initialized (%s)\n", name);
 175
 176         return;
 177
 178 error:
 179         return;
 180 }