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 } 181