drivers/macintosh/via-pmu-backlight.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Backlight code for via-pmu
   4  *
   5  * Copyright (C) 1998 Paul Mackerras and Fabio Riccardi.
   6  * Copyright (C) 2001-2002 Benjamin Herrenschmidt
   7  * Copyright (C) 2006      Michael Hanselmann <linux-kernel@hansmi.ch>
   8  *
   9  */
  10
  11 #include <asm/ptrace.h>
  12 #include <linux/adb.h>
  13 #include <linux/pmu.h>
  14 #include <asm/backlight.h>
  15
  16 #define MAX_PMU_LEVEL 0xFF
  17
  18 static const struct backlight_ops pmu_backlight_data;
  19 static DEFINE_SPINLOCK(pmu_backlight_lock);
  20 static int sleeping, uses_pmu_bl;
  21 static u8 bl_curve[FB_BACKLIGHT_LEVELS];
  22
  23 static void pmu_backlight_init_curve(u8 off, u8 min, u8 max)
  24 {
  25         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         int level = backlight_get_brightness(bd);
  75
  76         if (level > 0) {
  77                 int pmulevel = pmu_backlight_get_level_brightness(level);
  78
  79                 pmu_request(&req, NULL, 2, PMU_BACKLIGHT_BRIGHT, pmulevel);
  80                 pmu_wait_complete(&req);
  81
  82                 pmu_request(&req, NULL, 2, PMU_POWER_CTRL,
  83                         PMU_POW_BACKLIGHT | PMU_POW_ON);
  84                 pmu_wait_complete(&req);
  85         } else {
  86                 pmu_request(&req, NULL, 2, PMU_POWER_CTRL,
  87                         PMU_POW_BACKLIGHT | PMU_POW_OFF);
  88                 pmu_wait_complete(&req);
  89         }
  90
  91         return 0;
  92 }
  93
  94 static int pmu_backlight_update_status(struct backlight_device *bd)
  95 {
  96         unsigned long flags;
  97         int rc = 0;
  98
  99         spin_lock_irqsave(&pmu_backlight_lock, flags);
 100         /* Don't update brightness when sleeping */
 101         if (!sleeping)
 102                 rc = __pmu_backlight_update_status(bd);
 103         spin_unlock_irqrestore(&pmu_backlight_lock, flags);
 104         return rc;
 105 }
 106
 107
 108 static const struct backlight_ops pmu_backlight_data = {
 109         .update_status  = pmu_backlight_update_status,
 110
 111 };
 112
 113 #ifdef CONFIG_PM
 114 void pmu_backlight_set_sleep(int sleep)
 115 {
 116         unsigned long flags;
 117
 118         spin_lock_irqsave(&pmu_backlight_lock, flags);
 119         sleeping = sleep;
 120         if (pmac_backlight && uses_pmu_bl) {
 121                 if (sleep) {
 122                         struct adb_request req;
 123
 124                         pmu_request(&req, NULL, 2, PMU_POWER_CTRL,
 125                                     PMU_POW_BACKLIGHT | PMU_POW_OFF);
 126                         pmu_wait_complete(&req);
 127                 } else
 128                         __pmu_backlight_update_status(pmac_backlight);
 129         }
 130         spin_unlock_irqrestore(&pmu_backlight_lock, flags);
 131 }
 132 #endif /* CONFIG_PM */
 133
 134 void __init pmu_backlight_init(void)
 135 {
 136         struct backlight_properties props;
 137         struct backlight_device *bd;
 138         char name[10];
 139         int level, autosave;
 140
 141         /* Special case for the old PowerBook since I can't test on it */
 142         autosave =
 143                 of_machine_is_compatible("AAPL,3400/2400") ||
 144                 of_machine_is_compatible("AAPL,3500");
 145
 146         if (!autosave &&
 147             !pmac_has_backlight_type("pmu") &&
 148             !of_machine_is_compatible("AAPL,PowerBook1998") &&
 149             !of_machine_is_compatible("PowerBook1,1"))
 150                 return;
 151
 152         snprintf(name, sizeof(name), "pmubl");
 153
 154         memset(&props, 0, sizeof(struct backlight_properties));
 155         props.type = BACKLIGHT_PLATFORM;
 156         props.max_brightness = FB_BACKLIGHT_LEVELS - 1;
 157         bd = backlight_device_register(name, NULL, NULL, &pmu_backlight_data,
 158                                        &props);
 159         if (IS_ERR(bd)) {
 160                 printk(KERN_ERR "PMU Backlight registration failed\n");
 161                 return;
 162         }
 163         uses_pmu_bl = 1;
 164         pmu_backlight_init_curve(0x7F, 0x46, 0x0E);
 165
 166         level = bd->props.max_brightness;
 167
 168         if (autosave) {
 169                 /* read autosaved value if available */
 170                 struct adb_request req;
 171                 pmu_request(&req, NULL, 2, 0xd9, 0);
 172                 pmu_wait_complete(&req);
 173
 174                 level = pmu_backlight_curve_lookup(
 175                                 (req.reply[0] >> 4) *
 176                                 bd->props.max_brightness / 15);
 177         }
 178
 179         bd->props.brightness = level;
 180         bd->props.power = FB_BLANK_UNBLANK;
 181         backlight_update_status(bd);
 182
 183         printk(KERN_INFO "PMU Backlight initialized (%s)\n", name);
 184 }