Commit dc2139c0 authored by Thomas Zimmermann's avatar Thomas Zimmermann Committed by Lee Jones
Browse files

leds: backlight trigger: Replace fb events with a dedicated function call 



Remove support for fb events from the led backlight trigger. Provide
the helper ledtrig_backlight_blank() instead. Call it from fbdev to
inform the trigger of changes to a display's blank state.

Fbdev maintains a list of all installed notifiers. Instead of the fbdev
notifiers, maintain an internal list of led backlight triggers.

v3:
- export ledtrig_backlight_blank()
v2:
- maintain global list of led backlight triggers (Lee)
- avoid IS_REACHABLE() in source file (Lee)
- notify on changes to blank state instead of display state
- use lock guards
- initialize led list and list mutex

Signed-off-by: default avatarThomas Zimmermann <tzimmermann@suse.de>
Acked-by: default avatarSimona Vetter <simona.vetter@ffwll.ch>
Link: https://lore.kernel.org/r/20250321095517.313713-11-tzimmermann@suse.de


Signed-off-by: default avatarLee Jones <lee@kernel.org>
parent 28f8bab7

drivers/leds/trigger/ledtrig-backlight.c

+17 −25
Original line number Diff line number Diff line
@@ -10,7 +10,6 @@ 
#include <linux/kernel.h>

#include <linux/slab.h>

#include <linux/init.h>

#include <linux/fb.h>

#include <linux/leds.h>

#include "../leds.h"
@@ -21,10 +20,14 @@ struct bl_trig_notifier { 
	struct led_classdev *led;

	int brightness;

	int old_status;

	struct notifier_block notifier;

	unsigned invert;



	struct list_head entry;

};



static DEFINE_MUTEX(ledtrig_backlight_list_mutex);

static LIST_HEAD(ledtrig_backlight_list);



static void ledtrig_backlight_notify_blank(struct bl_trig_notifier *n, int new_status)

{

	struct led_classdev *led = n->led;
@@ -42,26 +45,17 @@ static void ledtrig_backlight_notify_blank(struct bl_trig_notifier *n, int new_s 
	n->old_status = new_status;

}



static int fb_notifier_callback(struct notifier_block *p,

				unsigned long event, void *data)

void ledtrig_backlight_blank(bool blank)

{

	struct bl_trig_notifier *n = container_of(p,

					struct bl_trig_notifier, notifier);

	struct fb_event *fb_event = data;

	int *blank;

	int new_status;



	/* If we aren't interested in this event, skip it immediately ... */

	if (event != FB_EVENT_BLANK)

		return 0;

	struct bl_trig_notifier *n;

	int new_status = blank ? BLANK : UNBLANK;



	blank = fb_event->data;

	new_status = *blank ? BLANK : UNBLANK;

	guard(mutex)(&ledtrig_backlight_list_mutex);



	list_for_each_entry(n, &ledtrig_backlight_list, entry)

		ledtrig_backlight_notify_blank(n, new_status);



	return 0;

}

EXPORT_SYMBOL(ledtrig_backlight_blank);



static ssize_t bl_trig_invert_show(struct device *dev,

		struct device_attribute *attr, char *buf)
@@ -106,8 +100,6 @@ ATTRIBUTE_GROUPS(bl_trig); 


static int bl_trig_activate(struct led_classdev *led)

{

	int ret;



	struct bl_trig_notifier *n;



	n = kzalloc(sizeof(struct bl_trig_notifier), GFP_KERNEL);
@@ -118,11 +110,9 @@ static int bl_trig_activate(struct led_classdev *led) 
	n->led = led;

	n->brightness = led->brightness;

	n->old_status = UNBLANK;

	n->notifier.notifier_call = fb_notifier_callback;



	ret = fb_register_client(&n->notifier);

	if (ret)

		dev_err(led->dev, "unable to register backlight trigger\n");

	guard(mutex)(&ledtrig_backlight_list_mutex);

	list_add(&n->entry, &ledtrig_backlight_list);



	return 0;

}
@@ -131,7 +121,9 @@ static void bl_trig_deactivate(struct led_classdev *led) 
{

	struct bl_trig_notifier *n = led_get_trigger_data(led);



	fb_unregister_client(&n->notifier);

	guard(mutex)(&ledtrig_backlight_list_mutex);

	list_del(&n->entry);



	kfree(n);

}

drivers/video/fbdev/core/fbmem.c

+10 −9
Original line number Diff line number Diff line
@@ -16,6 +16,7 @@ 
#include <linux/fb.h>

#include <linux/fbcon.h>

#include <linux/lcd.h>

#include <linux/leds.h>



#include <video/nomodeset.h>
@@ -369,11 +370,17 @@ static void fb_lcd_notify_blank(struct fb_info *info) 
	lcd_notify_blank_all(info->device, power);

}



static void fb_ledtrig_backlight_notify_blank(struct fb_info *info)

{

	if (info->blank == FB_BLANK_UNBLANK)

		ledtrig_backlight_blank(false);

	else

		ledtrig_backlight_blank(true);

}



int fb_blank(struct fb_info *info, int blank)

{

	int old_blank = info->blank;

	struct fb_event event;

	int data[2];

	int ret;



	if (!info->fbops->fb_blank)
@@ -382,11 +389,6 @@ int fb_blank(struct fb_info *info, int blank) 
	if (blank > FB_BLANK_POWERDOWN)

		blank = FB_BLANK_POWERDOWN;



	data[0] = blank;

	data[1] = old_blank;

	event.info = info;

	event.data = data;



	info->blank = blank;



	ret = info->fbops->fb_blank(blank, info);
@@ -395,8 +397,7 @@ int fb_blank(struct fb_info *info, int blank) 


	fb_bl_notify_blank(info, old_blank);

	fb_lcd_notify_blank(info);



	fb_notifier_call_chain(FB_EVENT_BLANK, &event);

	fb_ledtrig_backlight_notify_blank(info);



	return 0;

include/linux/leds.h

+6 −0
Original line number Diff line number Diff line
@@ -640,6 +640,12 @@ static inline void ledtrig_flash_ctrl(bool on) {} 
static inline void ledtrig_torch_ctrl(bool on) {}

#endif



#if IS_REACHABLE(CONFIG_LEDS_TRIGGER_BACKLIGHT)

void ledtrig_backlight_blank(bool blank);

#else

static inline void ledtrig_backlight_blank(bool blank) {}

#endif



/*

 * Generic LED platform data for describing LED names and default triggers.

 */