e6c6fea5c3
Framebuffer drivers for devices with dedicated backlight are supposed to set struct fb_info.bl_dev to the backlight's respective device. Use the value to match backlight and framebuffer in the backlight core code. The code first tests against struct backlight_ops.check_ops. If this test succeeds, it performs the test against fbdev. So backlight drivers can override the later test as before. Fbdev's backlight support depends on CONFIG_FB_BACKLIGHT. To avoid ifdef in the code, the new helper fb_bl_device() returns the backlight device, or NULL if the config option has been disabled. The test in the backlight code will then do nothing. v4: * declare empty fb_bl_device() as static inline * export fb_bl_device() v3: * hide ifdef in fb_bl_device() (Lee) * no if-else blocks (Andy) Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de> Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org> Reviewed-by: Javier Martinez Canillas <javierm@redhat.com> Link: https://lore.kernel.org/r/20240305162425.23845-2-tzimmermann@suse.de Signed-off-by: Lee Jones <lee@kernel.org>
39 lines
911 B
C
39 lines
911 B
C
// SPDX-License-Identifier: GPL-2.0-or-later
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#include <linux/export.h>
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#include <linux/fb.h>
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#include <linux/mutex.h>
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#if IS_ENABLED(CONFIG_FB_BACKLIGHT)
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/*
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* This function generates a linear backlight curve
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*
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* 0: off
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* 1-7: min
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* 8-127: linear from min to max
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*/
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void fb_bl_default_curve(struct fb_info *fb_info, u8 off, u8 min, u8 max)
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{
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unsigned int i, flat, count, range = (max - min);
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mutex_lock(&fb_info->bl_curve_mutex);
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fb_info->bl_curve[0] = off;
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for (flat = 1; flat < (FB_BACKLIGHT_LEVELS / 16); ++flat)
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fb_info->bl_curve[flat] = min;
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count = FB_BACKLIGHT_LEVELS * 15 / 16;
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for (i = 0; i < count; ++i)
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fb_info->bl_curve[flat + i] = min + (range * (i + 1) / count);
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mutex_unlock(&fb_info->bl_curve_mutex);
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}
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EXPORT_SYMBOL_GPL(fb_bl_default_curve);
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struct backlight_device *fb_bl_device(struct fb_info *info)
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{
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return info->bl_dev;
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}
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EXPORT_SYMBOL(fb_bl_device);
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#endif
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