diff options
Diffstat (limited to 'arch/powerpc/platforms/powermac/backlight.c')
| -rw-r--r-- | arch/powerpc/platforms/powermac/backlight.c | 220 |
1 files changed, 220 insertions, 0 deletions
diff --git a/arch/powerpc/platforms/powermac/backlight.c b/arch/powerpc/platforms/powermac/backlight.c new file mode 100644 index 000000000..aeb79a8b3 --- /dev/null +++ b/arch/powerpc/platforms/powermac/backlight.c @@ -0,0 +1,220 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * 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 <linux/atomic.h> +#include <linux/export.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(void) +{ + 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(void) +{ + atomic_inc(&kernel_backlight_disabled); +} + +void pmac_backlight_enable(void) +{ + atomic_dec(&kernel_backlight_disabled); +} + +EXPORT_SYMBOL_GPL(pmac_backlight); +EXPORT_SYMBOL_GPL(pmac_backlight_mutex); +EXPORT_SYMBOL_GPL(pmac_has_backlight_type); |