arch/powerpc/platforms/powermac/backlight.c

   1 /*
   2  * Miscellaneous procedures for dealing with the PowerMac hardware.
   3  * Contains support for the backlight.
   4  *
   5  *   Copyright (C) 2000 Benjamin Herrenschmidt
   6  *
   7  */
   8
   9 #include <linux/config.h>
  10 #include <linux/kernel.h>
  11 #include <linux/module.h>
  12 #include <linux/stddef.h>
  13 #include <linux/reboot.h>
  14 #include <linux/nvram.h>
  15 #include <linux/console.h>
  16 #include <asm/sections.h>
  17 #include <asm/ptrace.h>
  18 #include <asm/io.h>
  19 #include <asm/pgtable.h>
  20 #include <asm/system.h>
  21 #include <asm/prom.h>
  22 #include <asm/machdep.h>
  23 #include <asm/nvram.h>
  24 #include <asm/backlight.h>
  25
  26 #include <linux/adb.h>
  27 #include <linux/pmu.h>
  28
  29 static struct backlight_controller *backlighter;
  30 static void* backlighter_data;
  31 static int backlight_autosave;
  32 static int backlight_level = BACKLIGHT_MAX;
  33 static int backlight_enabled = 1;
  34 static int backlight_req_level = -1;
  35 static int backlight_req_enable = -1;
  36
  37 static void backlight_callback(void *);
  38 static DECLARE_WORK(backlight_work, backlight_callback, NULL);
  39
  40 void register_backlight_controller(struct backlight_controller *ctrler,
  41                                           void *data, char *type)
  42 {
  43         struct device_node* bk_node;
  44         char *prop;
  45         int valid = 0;
  46
  47         /* There's already a matching controller, bail out */
  48         if (backlighter != NULL)
  49                 return;
  50
  51         bk_node = find_devices("backlight");
  52
  53 #ifdef CONFIG_ADB_PMU
  54         /* Special case for the old PowerBook since I can't test on it */
  55         backlight_autosave = machine_is_compatible("AAPL,3400/2400")
  56                 || machine_is_compatible("AAPL,3500");
  57         if ((backlight_autosave
  58              || machine_is_compatible("AAPL,PowerBook1998")
  59              || machine_is_compatible("PowerBook1,1"))
  60             && !strcmp(type, "pmu"))
  61                 valid = 1;
  62 #endif
  63         if (bk_node) {
  64                 prop = get_property(bk_node, "backlight-control", NULL);
  65                 if (prop && !strncmp(prop, type, strlen(type)))
  66                         valid = 1;
  67         }
  68         if (!valid)
  69                 return;
  70         backlighter = ctrler;
  71         backlighter_data = data;
  72
  73         if (bk_node && !backlight_autosave)
  74                 prop = get_property(bk_node, "bklt", NULL);
  75         else
  76                 prop = NULL;
  77         if (prop) {
  78                 backlight_level = ((*prop)+1) >> 1;
  79                 if (backlight_level > BACKLIGHT_MAX)
  80                         backlight_level = BACKLIGHT_MAX;
  81         }
  82
  83 #ifdef CONFIG_ADB_PMU
  84         if (backlight_autosave) {
  85                 struct adb_request req;
  86                 pmu_request(&req, NULL, 2, 0xd9, 0);
  87                 while (!req.complete)
  88                         pmu_poll();
  89                 backlight_level = req.reply[0] >> 4;
  90         }
  91 #endif
  92         acquire_console_sem();
  93         if (!backlighter->set_enable(1, backlight_level, data))
  94                 backlight_enabled = 1;
  95         release_console_sem();
  96
  97         printk(KERN_INFO "Registered \"%s\" backlight controller,"
  98                "level: %d/15\n", type, backlight_level);
  99 }
 100 EXPORT_SYMBOL(register_backlight_controller);
 101
 102 void unregister_backlight_controller(struct backlight_controller
 103                                             *ctrler, void *data)
 104 {
 105         /* We keep the current backlight level (for now) */
 106         if (ctrler == backlighter && data == backlighter_data)
 107                 backlighter = NULL;
 108 }
 109 EXPORT_SYMBOL(unregister_backlight_controller);
 110
 111 static int __set_backlight_enable(int enable)
 112 {
 113         int rc;
 114
 115         if (!backlighter)
 116                 return -ENODEV;
 117         acquire_console_sem();
 118         rc = backlighter->set_enable(enable, backlight_level,
 119                                      backlighter_data);
 120         if (!rc)
 121                 backlight_enabled = enable;
 122         release_console_sem();
 123         return rc;
 124 }
 125 int set_backlight_enable(int enable)
 126 {
 127         if (!backlighter)
 128                 return -ENODEV;
 129         backlight_req_enable = enable;
 130         schedule_work(&backlight_work);
 131         return 0;
 132 }
 133
 134 EXPORT_SYMBOL(set_backlight_enable);
 135
 136 int get_backlight_enable(void)
 137 {
 138         if (!backlighter)
 139                 return -ENODEV;
 140         return backlight_enabled;
 141 }
 142 EXPORT_SYMBOL(get_backlight_enable);
 143
 144 static int __set_backlight_level(int level)
 145 {
 146         int rc = 0;
 147
 148         if (!backlighter)
 149                 return -ENODEV;
 150         if (level < BACKLIGHT_MIN)
 151                 level = BACKLIGHT_OFF;
 152         if (level > BACKLIGHT_MAX)
 153                 level = BACKLIGHT_MAX;
 154         acquire_console_sem();
 155         if (backlight_enabled)
 156                 rc = backlighter->set_level(level, backlighter_data);
 157         if (!rc)
 158                 backlight_level = level;
 159         release_console_sem();
 160         if (!rc && !backlight_autosave) {
 161                 level <<=1;
 162                 if (level & 0x10)
 163                         level |= 0x01;
 164                 // -- todo: save to property "bklt"
 165         }
 166         return rc;
 167 }
 168 int set_backlight_level(int level)
 169 {
 170         if (!backlighter)
 171                 return -ENODEV;
 172         backlight_req_level = level;
 173         schedule_work(&backlight_work);
 174         return 0;
 175 }
 176
 177 EXPORT_SYMBOL(set_backlight_level);
 178
 179 int get_backlight_level(void)
 180 {
 181         if (!backlighter)
 182                 return -ENODEV;
 183         return backlight_level;
 184 }
 185 EXPORT_SYMBOL(get_backlight_level);
 186
 187 static void backlight_callback(void *dummy)
 188 {
 189         int level, enable;
 190
 191         do {
 192                 level = backlight_req_level;
 193                 enable = backlight_req_enable;
 194                 mb();
 195
 196                 if (level >= 0)
 197                         __set_backlight_level(level);
 198                 if (enable >= 0)
 199                         __set_backlight_enable(enable);
 200         } while(cmpxchg(&backlight_req_level, level, -1) != level ||
 201                 cmpxchg(&backlight_req_enable, enable, -1) != enable);
 202 }