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 = FB_BLANK_UNBLANK; 182 backlight_update_status(bd); 183 184 printk(KERN_INFO "PMU Backlight initialized (%s)\n", name); 185 } 186