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 #include <asm/prom.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 = bd->props.brightness; 76 77 78 if (bd->props.power != FB_BLANK_UNBLANK || 79 bd->props.fb_blank != FB_BLANK_UNBLANK) 80 level = 0; 81 82 if (level > 0) { 83 int pmulevel = pmu_backlight_get_level_brightness(level); 84 85 pmu_request(&req, NULL, 2, PMU_BACKLIGHT_BRIGHT, pmulevel); 86 pmu_wait_complete(&req); 87 88 pmu_request(&req, NULL, 2, PMU_POWER_CTRL, 89 PMU_POW_BACKLIGHT | PMU_POW_ON); 90 pmu_wait_complete(&req); 91 } else { 92 pmu_request(&req, NULL, 2, PMU_POWER_CTRL, 93 PMU_POW_BACKLIGHT | PMU_POW_OFF); 94 pmu_wait_complete(&req); 95 } 96 97 return 0; 98 } 99 100 static int pmu_backlight_update_status(struct backlight_device *bd) 101 { 102 unsigned long flags; 103 int rc = 0; 104 105 spin_lock_irqsave(&pmu_backlight_lock, flags); 106 /* Don't update brightness when sleeping */ 107 if (!sleeping) 108 rc = __pmu_backlight_update_status(bd); 109 spin_unlock_irqrestore(&pmu_backlight_lock, flags); 110 return rc; 111 } 112 113 114 static const struct backlight_ops pmu_backlight_data = { 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 if (pmac_backlight && uses_pmu_bl) { 127 if (sleep) { 128 struct adb_request req; 129 130 pmu_request(&req, NULL, 2, PMU_POWER_CTRL, 131 PMU_POW_BACKLIGHT | PMU_POW_OFF); 132 pmu_wait_complete(&req); 133 } else 134 __pmu_backlight_update_status(pmac_backlight); 135 } 136 spin_unlock_irqrestore(&pmu_backlight_lock, flags); 137 } 138 #endif /* CONFIG_PM */ 139 140 void __init pmu_backlight_init(void) 141 { 142 struct backlight_properties props; 143 struct backlight_device *bd; 144 char name[10]; 145 int level, autosave; 146 147 /* Special case for the old PowerBook since I can't test on it */ 148 autosave = 149 of_machine_is_compatible("AAPL,3400/2400") || 150 of_machine_is_compatible("AAPL,3500"); 151 152 if (!autosave && 153 !pmac_has_backlight_type("pmu") && 154 !of_machine_is_compatible("AAPL,PowerBook1998") && 155 !of_machine_is_compatible("PowerBook1,1")) 156 return; 157 158 snprintf(name, sizeof(name), "pmubl"); 159 160 memset(&props, 0, sizeof(struct backlight_properties)); 161 props.type = BACKLIGHT_PLATFORM; 162 props.max_brightness = FB_BACKLIGHT_LEVELS - 1; 163 bd = backlight_device_register(name, NULL, NULL, &pmu_backlight_data, 164 &props); 165 if (IS_ERR(bd)) { 166 printk(KERN_ERR "PMU Backlight registration failed\n"); 167 return; 168 } 169 uses_pmu_bl = 1; 170 pmu_backlight_init_curve(0x7F, 0x46, 0x0E); 171 172 level = bd->props.max_brightness; 173 174 if (autosave) { 175 /* read autosaved value if available */ 176 struct adb_request req; 177 pmu_request(&req, NULL, 2, 0xd9, 0); 178 pmu_wait_complete(&req); 179 180 level = pmu_backlight_curve_lookup( 181 (req.reply[0] >> 4) * 182 bd->props.max_brightness / 15); 183 } 184 185 bd->props.brightness = level; 186 bd->props.power = FB_BLANK_UNBLANK; 187 backlight_update_status(bd); 188 189 printk(KERN_INFO "PMU Backlight initialized (%s)\n", name); 190 } 191