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/backlight.h>
  14 #include <linux/pmu.h>
  15 #include <asm/backlight.h>
  16
  17 #define MAX_PMU_LEVEL 0xFF
  18
  19 static const struct backlight_ops pmu_backlight_data;
  20 static DEFINE_SPINLOCK(pmu_backlight_lock);
  21 static int sleeping, uses_pmu_bl;
  22 static u8 bl_curve[FB_BACKLIGHT_LEVELS];
  23
  24 static void pmu_backlight_init_curve(u8 off, u8 min, u8 max)
  25 {
  26         int i, flat, count, range = (max - min);
  27
  28         bl_curve[0] = off;
  29
  30         for (flat = 1; flat < (FB_BACKLIGHT_LEVELS / 16); ++flat)
  31                 bl_curve[flat] = min;
  32
  33         count = FB_BACKLIGHT_LEVELS * 15 / 16;
  34         for (i = 0; i < count; ++i)
  35                 bl_curve[flat + i] = min + (range * (i + 1) / count);
  36 }
  37
  38 static int pmu_backlight_curve_lookup(int value)
  39 {
  40         int level = (FB_BACKLIGHT_LEVELS - 1);
  41         int i, max = 0;
  42
  43         /* Look for biggest value */
  44         for (i = 0; i < FB_BACKLIGHT_LEVELS; i++)
  45                 max = max((int)bl_curve[i], max);
  46
  47         /* Look for nearest value */
  48         for (i = 0; i < FB_BACKLIGHT_LEVELS; i++) {
  49                 int diff = abs(bl_curve[i] - value);
  50                 if (diff < max) {
  51                         max = diff;
  52                         level = i;
  53                 }
  54         }
  55         return level;
  56 }
  57
  58 static int pmu_backlight_get_level_brightness(int level)
  59 {
  60         int pmulevel;
  61
  62         /* Get and convert the value */
  63         pmulevel = bl_curve[level] * FB_BACKLIGHT_MAX / MAX_PMU_LEVEL;
  64         if (pmulevel < 0)
  65                 pmulevel = 0;
  66         else if (pmulevel > MAX_PMU_LEVEL)
  67                 pmulevel = MAX_PMU_LEVEL;
  68
  69         return pmulevel;
  70 }
  71
  72 static int __pmu_backlight_update_status(struct backlight_device *bd)
  73 {
  74         struct adb_request req;
  75         int level = backlight_get_brightness(bd);
  76
  77         if (level > 0) {
  78                 int pmulevel = pmu_backlight_get_level_brightness(level);
  79
  80                 pmu_request(&req, NULL, 2, PMU_BACKLIGHT_BRIGHT, pmulevel);
  81                 pmu_wait_complete(&req);
  82
  83                 pmu_request(&req, NULL, 2, PMU_POWER_CTRL,
  84                         PMU_POW_BACKLIGHT | PMU_POW_ON);
  85                 pmu_wait_complete(&req);
  86         } else {
  87                 pmu_request(&req, NULL, 2, PMU_POWER_CTRL,
  88                         PMU_POW_BACKLIGHT | PMU_POW_OFF);
  89                 pmu_wait_complete(&req);
  90         }
  91
  92         return 0;
  93 }
  94
  95 static int pmu_backlight_update_status(struct backlight_device *bd)
  96 {
  97         unsigned long flags;
  98         int rc = 0;
  99
 100         spin_lock_irqsave(&pmu_backlight_lock, flags);
 101         /* Don't update brightness when sleeping */
 102         if (!sleeping)
 103                 rc = __pmu_backlight_update_status(bd);
 104         spin_unlock_irqrestore(&pmu_backlight_lock, flags);
 105         return rc;
 106 }
 107
 108
 109 static const struct backlight_ops pmu_backlight_data = {
 110         .update_status  = pmu_backlight_update_status,
 111
 112 };
 113
 114 #ifdef CONFIG_PM
 115 void pmu_backlight_set_sleep(int sleep)
 116 {
 117         unsigned long flags;
 118
 119         spin_lock_irqsave(&pmu_backlight_lock, flags);
 120         sleeping = sleep;
 121         if (pmac_backlight && uses_pmu_bl) {
 122                 if (sleep) {
 123                         struct adb_request req;
 124
 125                         pmu_request(&req, NULL, 2, PMU_POWER_CTRL,
 126                                     PMU_POW_BACKLIGHT | PMU_POW_OFF);
 127                         pmu_wait_complete(&req);
 128                 } else
 129                         __pmu_backlight_update_status(pmac_backlight);
 130         }
 131         spin_unlock_irqrestore(&pmu_backlight_lock, flags);
 132 }
 133 #endif /* CONFIG_PM */
 134
 135 void __init pmu_backlight_init(void)
 136 {
 137         struct backlight_properties props;
 138         struct backlight_device *bd;
 139         char name[10];
 140         int level, autosave;
 141
 142         /* Special case for the old PowerBook since I can't test on it */
 143         autosave =
 144                 of_machine_is_compatible("AAPL,3400/2400") ||
 145                 of_machine_is_compatible("AAPL,3500");
 146
 147         if (!autosave &&
 148             !pmac_has_backlight_type("pmu") &&
 149             !of_machine_is_compatible("AAPL,PowerBook1998") &&
 150             !of_machine_is_compatible("PowerBook1,1"))
 151                 return;
 152
 153         snprintf(name, sizeof(name), "pmubl");
 154
 155         memset(&props, 0, sizeof(struct backlight_properties));
 156         props.type = BACKLIGHT_PLATFORM;
 157         props.max_brightness = FB_BACKLIGHT_LEVELS - 1;
 158         bd = backlight_device_register(name, NULL, NULL, &pmu_backlight_data,
 159                                        &props);
 160         if (IS_ERR(bd)) {
 161                 printk(KERN_ERR "PMU Backlight registration failed\n");
 162                 return;
 163         }
 164         uses_pmu_bl = 1;
 165         pmu_backlight_init_curve(0x7F, 0x46, 0x0E);
 166
 167         level = bd->props.max_brightness;
 168
 169         if (autosave) {
 170                 /* read autosaved value if available */
 171                 struct adb_request req;
 172                 pmu_request(&req, NULL, 2, 0xd9, 0);
 173                 pmu_wait_complete(&req);
 174
 175                 level = pmu_backlight_curve_lookup(
 176                                 (req.reply[0] >> 4) *
 177                                 bd->props.max_brightness / 15);
 178         }
 179
 180         bd->props.brightness = level;
 181         bd->props.power = BACKLIGHT_POWER_ON;
 182         backlight_update_status(bd);
 183
 184         printk(KERN_INFO "PMU Backlight initialized (%s)\n", name);
 185 }