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 } 185