/* * Miscellaneous procedures for dealing with the PowerMac hardware. * Contains support for the backlight. * * Copyright (C) 2000 Benjamin Herrenschmidt * Copyright (C) 2006 Michael Hanselmann <linux-kernel@hansmi.ch> * */ #include <linux/kernel.h> #include <linux/fb.h> #include <linux/backlight.h> #include <linux/adb.h> #include <linux/pmu.h> #include <asm/atomic.h> #include <asm/prom.h> #include <asm/backlight.h> #define OLD_BACKLIGHT_MAX 15 static void pmac_backlight_key_worker(struct work_struct *work); static void pmac_backlight_set_legacy_worker(struct work_struct *work); static DECLARE_WORK(pmac_backlight_key_work, pmac_backlight_key_worker); static DECLARE_WORK(pmac_backlight_set_legacy_work, pmac_backlight_set_legacy_worker); /* Although these variables are used in interrupt context, it makes no sense to * protect them. No user is able to produce enough key events per second and * notice the errors that might happen. */ static int pmac_backlight_key_queued; static int pmac_backlight_set_legacy_queued; /* The via-pmu code allows the backlight to be grabbed, in which case the * in-kernel control of the brightness needs to be disabled. This should * only be used by really old PowerBooks. */ static atomic_t kernel_backlight_disabled = ATOMIC_INIT(0); /* Protect the pmac_backlight variable below. You should hold this lock when using the pmac_backlight pointer to prevent its potential removal. */ DEFINE_MUTEX(pmac_backlight_mutex); /* Main backlight storage * * Backlight drivers in this variable are required to have the "ops" * attribute set and to have an update_status function. * * We can only store one backlight here, but since Apple laptops have only one * internal display, it doesn't matter. Other backlight drivers can be used * independently. * */ struct backlight_device *pmac_backlight; int pmac_has_backlight_type(const char *type) { struct device_node* bk_node = of_find_node_by_name(NULL, "backlight"); if (bk_node) { const char *prop = of_get_property(bk_node, "backlight-control", NULL); if (prop && strncmp(prop, type, strlen(type)) == 0) { of_node_put(bk_node); return 1; } of_node_put(bk_node); } return 0; } int pmac_backlight_curve_lookup(struct fb_info *info, int value) { int level = (FB_BACKLIGHT_LEVELS - 1); if (info && info->bl_dev) { int i, max = 0; /* Look for biggest value */ for (i = 0; i < FB_BACKLIGHT_LEVELS; i++) max = max((int)info->bl_curve[i], max); /* Look for nearest value */ for (i = 0; i < FB_BACKLIGHT_LEVELS; i++) { int diff = abs(info->bl_curve[i] - value); if (diff < max) { max = diff; level = i; } } } return level; } static void pmac_backlight_key_worker(struct work_struct *work) { if (atomic_read(&kernel_backlight_disabled)) return; mutex_lock(&pmac_backlight_mutex); if (pmac_backlight) { struct backlight_properties *props; int brightness; props = &pmac_backlight->props; brightness = props->brightness + ((pmac_backlight_key_queued?-1:1) * (props->max_brightness / 15)); if (brightness < 0) brightness = 0; else if (brightness > props->max_brightness) brightness = props->max_brightness; props->brightness = brightness; backlight_update_status(pmac_backlight); } mutex_unlock(&pmac_backlight_mutex); } /* This function is called in interrupt context */ void pmac_backlight_key(int direction) { if (atomic_read(&kernel_backlight_disabled)) return; /* we can receive multiple interrupts here, but the scheduled work * will run only once, with the last value */ pmac_backlight_key_queued = direction; schedule_work(&pmac_backlight_key_work); } static int __pmac_backlight_set_legacy_brightness(int brightness) { int error = -ENXIO; mutex_lock(&pmac_backlight_mutex); if (pmac_backlight) { struct backlight_properties *props; props = &pmac_backlight->props; props->brightness = brightness * (props->max_brightness + 1) / (OLD_BACKLIGHT_MAX + 1); if (props->brightness > props->max_brightness) props->brightness = props->max_brightness; else if (props->brightness < 0) props->brightness = 0; backlight_update_status(pmac_backlight); error = 0; } mutex_unlock(&pmac_backlight_mutex); return error; } static void pmac_backlight_set_legacy_worker(struct work_struct *work) { if (atomic_read(&kernel_backlight_disabled)) return; __pmac_backlight_set_legacy_brightness(pmac_backlight_set_legacy_queued); } /* This function is called in interrupt context */ void pmac_backlight_set_legacy_brightness_pmu(int brightness) { if (atomic_read(&kernel_backlight_disabled)) return; pmac_backlight_set_legacy_queued = brightness; schedule_work(&pmac_backlight_set_legacy_work); } int pmac_backlight_set_legacy_brightness(int brightness) { return __pmac_backlight_set_legacy_brightness(brightness); } int pmac_backlight_get_legacy_brightness() { int result = -ENXIO; mutex_lock(&pmac_backlight_mutex); if (pmac_backlight) { struct backlight_properties *props; props = &pmac_backlight->props; result = props->brightness * (OLD_BACKLIGHT_MAX + 1) / (props->max_brightness + 1); } mutex_unlock(&pmac_backlight_mutex); return result; } void pmac_backlight_disable() { atomic_inc(&kernel_backlight_disabled); } void pmac_backlight_enable() { atomic_dec(&kernel_backlight_disabled); } EXPORT_SYMBOL_GPL(pmac_backlight); EXPORT_SYMBOL_GPL(pmac_backlight_mutex); EXPORT_SYMBOL_GPL(pmac_has_backlight_type);