Commit 7aa7d608 authored by Linus Torvalds's avatar Linus Torvalds

Merge tag 'leds_for_4.11' of git://git.kernel.org/pub/scm/linux/kernel/git/j.anaszewski/linux-leds

Pull LED updates from Jacek Anaszewski:
 "New features and improvements:

   - add new optional brightness_hw_changed attribute for the LEDs that
     may have their brightness level changed autonomously (outside of
     kernel control) by hardware / firmware. The attribute supports
     userspace notifications through POLLPRI events

   - add led_brightness_hw_mon tool that demonstrates how to use the
     aforementioned feature

   - add LED_ON enum for LEDs that can be only turned on/off, and don't
     allow setting other brightness levels

   - allow for adjusting heartbeat trigger blink brightness level

  Fixes and cleanups:

   - avoid harmless maybe-uninitialized warning in leds-ktd2692.c

   - add context to the existing example entries in common LED bindings
     to make the documentation more clear"

* tag 'leds_for_4.11' of git://git.kernel.org/pub/scm/linux/kernel/git/j.anaszewski/linux-leds:
  leds: ledtrig-heartbeat: Make top brightness adjustable
  tools/leds: Add led_hw_brightness_mon program
  leds: class: Add new optional brightness_hw_changed attribute
  leds: ktd2692: avoid harmless maybe-uninitialized warning
  leds: add LED_ON brightness as boolean value
  DT: leds: Improve examples by adding some context
parents 85adbcd5 fb3d7691
......@@ -23,6 +23,23 @@ Description:
If the LED does not support different brightness levels, this
should be 1.
What: /sys/class/leds/<led>/brightness_hw_changed
Date: January 2017
KernelVersion: 4.11
Description:
Last hardware set brightness level for this LED. Some LEDs
may be changed autonomously by hardware/firmware. Only LEDs
where this happens and the driver can detect this, will have
this file.
This file supports poll() to detect when the hardware changes
the brightness.
Reading this file will return the last brightness level set
by the hardware, this may be different from the current
brightness. Reading this file when no hw brightness change
event has happened will return an ENODATA error.
What: /sys/class/leds/<led>/trigger
Date: March 2006
KernelVersion: 2.6.17
......
......@@ -61,16 +61,24 @@ property can be omitted.
Examples:
system-status {
label = "Status";
linux,default-trigger = "heartbeat";
...
gpio-leds {
compatible = "gpio-leds";
system-status {
label = "Status";
linux,default-trigger = "heartbeat";
gpios = <&gpio0 0 GPIO_ACTIVE_HIGH>;
};
};
camera-flash {
label = "Flash";
led-sources = <0>, <1>;
led-max-microamp = <50000>;
flash-max-microamp = <320000>;
flash-max-timeout-us = <500000>;
max77693-led {
compatible = "maxim,max77693-led";
camera-flash {
label = "Flash";
led-sources = <0>, <1>;
led-max-microamp = <50000>;
flash-max-microamp = <320000>;
flash-max-timeout-us = <500000>;
};
};
......@@ -65,6 +65,21 @@ LED subsystem core exposes following API for setting brightness:
blinking, returns -EBUSY if software blink fallback is enabled.
LED registration API
====================
A driver wanting to register a LED classdev for use by other drivers /
userspace needs to allocate and fill a led_classdev struct and then call
[devm_]led_classdev_register. If the non devm version is used the driver
must call led_classdev_unregister from its remove function before
free-ing the led_classdev struct.
If the driver can detect hardware initiated brightness changes and thus
wants to have a brightness_hw_changed attribute then the LED_BRIGHT_HW_CHANGED
flag must be set in flags before registering. Calling
led_classdev_notify_brightness_hw_changed on a classdev not registered with
the LED_BRIGHT_HW_CHANGED flag is a bug and will trigger a WARN_ON.
Hardware accelerated blink of LEDs
==================================
......
......@@ -29,6 +29,15 @@ config LEDS_CLASS_FLASH
for the flash related features of a LED device. It can be built
as a module.
config LEDS_BRIGHTNESS_HW_CHANGED
bool "LED Class brightness_hw_changed attribute support"
depends on LEDS_CLASS
help
This option enables support for the brightness_hw_changed attribute
for led sysfs class devices under /sys/class/leds.
See Documentation/ABI/testing/sysfs-class-led for details.
comment "LED drivers"
config LEDS_88PM860X
......
......@@ -103,6 +103,68 @@ static const struct attribute_group *led_groups[] = {
NULL,
};
#ifdef CONFIG_LEDS_BRIGHTNESS_HW_CHANGED
static ssize_t brightness_hw_changed_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct led_classdev *led_cdev = dev_get_drvdata(dev);
if (led_cdev->brightness_hw_changed == -1)
return -ENODATA;
return sprintf(buf, "%u\n", led_cdev->brightness_hw_changed);
}
static DEVICE_ATTR_RO(brightness_hw_changed);
static int led_add_brightness_hw_changed(struct led_classdev *led_cdev)
{
struct device *dev = led_cdev->dev;
int ret;
ret = device_create_file(dev, &dev_attr_brightness_hw_changed);
if (ret) {
dev_err(dev, "Error creating brightness_hw_changed\n");
return ret;
}
led_cdev->brightness_hw_changed_kn =
sysfs_get_dirent(dev->kobj.sd, "brightness_hw_changed");
if (!led_cdev->brightness_hw_changed_kn) {
dev_err(dev, "Error getting brightness_hw_changed kn\n");
device_remove_file(dev, &dev_attr_brightness_hw_changed);
return -ENXIO;
}
return 0;
}
static void led_remove_brightness_hw_changed(struct led_classdev *led_cdev)
{
sysfs_put(led_cdev->brightness_hw_changed_kn);
device_remove_file(led_cdev->dev, &dev_attr_brightness_hw_changed);
}
void led_classdev_notify_brightness_hw_changed(struct led_classdev *led_cdev,
enum led_brightness brightness)
{
if (WARN_ON(!led_cdev->brightness_hw_changed_kn))
return;
led_cdev->brightness_hw_changed = brightness;
sysfs_notify_dirent(led_cdev->brightness_hw_changed_kn);
}
EXPORT_SYMBOL_GPL(led_classdev_notify_brightness_hw_changed);
#else
static int led_add_brightness_hw_changed(struct led_classdev *led_cdev)
{
return 0;
}
static void led_remove_brightness_hw_changed(struct led_classdev *led_cdev)
{
}
#endif
/**
* led_classdev_suspend - suspend an led_classdev.
* @led_cdev: the led_classdev to suspend.
......@@ -204,9 +266,20 @@ int led_classdev_register(struct device *parent, struct led_classdev *led_cdev)
dev_warn(parent, "Led %s renamed to %s due to name collision",
led_cdev->name, dev_name(led_cdev->dev));
if (led_cdev->flags & LED_BRIGHT_HW_CHANGED) {
ret = led_add_brightness_hw_changed(led_cdev);
if (ret) {
device_unregister(led_cdev->dev);
return ret;
}
}
led_cdev->work_flags = 0;
#ifdef CONFIG_LEDS_TRIGGERS
init_rwsem(&led_cdev->trigger_lock);
#endif
#ifdef CONFIG_LEDS_BRIGHTNESS_HW_CHANGED
led_cdev->brightness_hw_changed = -1;
#endif
mutex_init(&led_cdev->led_access);
/* add to the list of leds */
......@@ -256,6 +329,9 @@ void led_classdev_unregister(struct led_classdev *led_cdev)
flush_work(&led_cdev->set_brightness_work);
if (led_cdev->flags & LED_BRIGHT_HW_CHANGED)
led_remove_brightness_hw_changed(led_cdev);
device_unregister(led_cdev->dev);
down_write(&leds_list_lock);
......
......@@ -270,15 +270,15 @@ static int ktd2692_parse_dt(struct ktd2692_context *led, struct device *dev,
return -ENXIO;
led->ctrl_gpio = devm_gpiod_get(dev, "ctrl", GPIOD_ASIS);
if (IS_ERR(led->ctrl_gpio)) {
ret = PTR_ERR(led->ctrl_gpio);
ret = PTR_ERR_OR_ZERO(led->ctrl_gpio);
if (ret) {
dev_err(dev, "cannot get ctrl-gpios %d\n", ret);
return ret;
}
led->aux_gpio = devm_gpiod_get(dev, "aux", GPIOD_ASIS);
if (IS_ERR(led->aux_gpio)) {
ret = PTR_ERR(led->aux_gpio);
ret = PTR_ERR_OR_ZERO(led->aux_gpio);
if (ret) {
dev_err(dev, "cannot get aux-gpios %d\n", ret);
return ret;
}
......
......@@ -43,6 +43,9 @@ static void led_heartbeat_function(unsigned long data)
return;
}
if (test_and_clear_bit(LED_BLINK_BRIGHTNESS_CHANGE, &led_cdev->work_flags))
led_cdev->blink_brightness = led_cdev->new_blink_brightness;
/* acts like an actual heart beat -- ie thump-thump-pause... */
switch (heartbeat_data->phase) {
case 0:
......@@ -59,26 +62,26 @@ static void led_heartbeat_function(unsigned long data)
delay = msecs_to_jiffies(70);
heartbeat_data->phase++;
if (!heartbeat_data->invert)
brightness = led_cdev->max_brightness;
brightness = led_cdev->blink_brightness;
break;
case 1:
delay = heartbeat_data->period / 4 - msecs_to_jiffies(70);
heartbeat_data->phase++;
if (heartbeat_data->invert)
brightness = led_cdev->max_brightness;
brightness = led_cdev->blink_brightness;
break;
case 2:
delay = msecs_to_jiffies(70);
heartbeat_data->phase++;
if (!heartbeat_data->invert)
brightness = led_cdev->max_brightness;
brightness = led_cdev->blink_brightness;
break;
default:
delay = heartbeat_data->period - heartbeat_data->period / 4 -
msecs_to_jiffies(70);
heartbeat_data->phase = 0;
if (heartbeat_data->invert)
brightness = led_cdev->max_brightness;
brightness = led_cdev->blink_brightness;
break;
}
......@@ -133,7 +136,10 @@ static void heartbeat_trig_activate(struct led_classdev *led_cdev)
setup_timer(&heartbeat_data->timer,
led_heartbeat_function, (unsigned long) led_cdev);
heartbeat_data->phase = 0;
if (!led_cdev->blink_brightness)
led_cdev->blink_brightness = led_cdev->max_brightness;
led_heartbeat_function(heartbeat_data->timer.data);
set_bit(LED_BLINK_SW, &led_cdev->work_flags);
led_cdev->activated = true;
}
......@@ -145,6 +151,7 @@ static void heartbeat_trig_deactivate(struct led_classdev *led_cdev)
del_timer_sync(&heartbeat_data->timer);
device_remove_file(led_cdev->dev, &dev_attr_invert);
kfree(heartbeat_data);
clear_bit(LED_BLINK_SW, &led_cdev->work_flags);
led_cdev->activated = false;
}
}
......
......@@ -13,6 +13,7 @@
#define __LINUX_LEDS_H_INCLUDED
#include <linux/device.h>
#include <linux/kernfs.h>
#include <linux/list.h>
#include <linux/mutex.h>
#include <linux/rwsem.h>
......@@ -27,6 +28,7 @@ struct device;
enum led_brightness {
LED_OFF = 0,
LED_ON = 1,
LED_HALF = 127,
LED_FULL = 255,
};
......@@ -46,6 +48,7 @@ struct led_classdev {
#define LED_DEV_CAP_FLASH (1 << 18)
#define LED_HW_PLUGGABLE (1 << 19)
#define LED_PANIC_INDICATOR (1 << 20)
#define LED_BRIGHT_HW_CHANGED (1 << 21)
/* set_brightness_work / blink_timer flags, atomic, private. */
unsigned long work_flags;
......@@ -110,6 +113,11 @@ struct led_classdev {
bool activated;
#endif
#ifdef CONFIG_LEDS_BRIGHTNESS_HW_CHANGED
int brightness_hw_changed;
struct kernfs_node *brightness_hw_changed_kn;
#endif
/* Ensures consistent access to the LED Flash Class device */
struct mutex led_access;
};
......@@ -422,4 +430,12 @@ static inline void ledtrig_cpu(enum cpu_led_event evt)
}
#endif
#ifdef CONFIG_LEDS_BRIGHTNESS_HW_CHANGED
extern void led_classdev_notify_brightness_hw_changed(
struct led_classdev *led_cdev, enum led_brightness brightness);
#else
static inline void led_classdev_notify_brightness_hw_changed(
struct led_classdev *led_cdev, enum led_brightness brightness) { }
#endif
#endif /* __LINUX_LEDS_H_INCLUDED */
......@@ -3,11 +3,11 @@
CC = $(CROSS_COMPILE)gcc
CFLAGS = -Wall -Wextra -g -I../../include/uapi
all: uledmon
all: uledmon led_hw_brightness_mon
%: %.c
$(CC) $(CFLAGS) -o $@ $^
clean:
$(RM) uledmon
$(RM) uledmon led_hw_brightness_mon
.PHONY: all clean
/*
* led_hw_brightness_mon.c
*
* This program monitors LED brightness level changes having its origin
* in hardware/firmware, i.e. outside of kernel control.
* A timestamp and brightness value is printed each time the brightness changes.
*
* Usage: led_hw_brightness_mon <device-name>
*
* <device-name> is the name of the LED class device to be monitored. Pressing
* CTRL+C will exit.
*/
#include <errno.h>
#include <fcntl.h>
#include <poll.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <unistd.h>
#include <linux/uleds.h>
int main(int argc, char const *argv[])
{
int fd, ret;
char brightness_file_path[LED_MAX_NAME_SIZE + 11];
struct pollfd pollfd;
struct timespec ts;
char buf[11];
if (argc != 2) {
fprintf(stderr, "Requires <device-name> argument\n");
return 1;
}
snprintf(brightness_file_path, LED_MAX_NAME_SIZE,
"/sys/class/leds/%s/brightness_hw_changed", argv[1]);
fd = open(brightness_file_path, O_RDONLY);
if (fd == -1) {
printf("Failed to open %s file\n", brightness_file_path);
return 1;
}
/*
* read may fail if no hw brightness change has occurred so far,
* but it is required to avoid spurious poll notifications in
* the opposite case.
*/
read(fd, buf, sizeof(buf));
pollfd.fd = fd;
pollfd.events = POLLPRI;
while (1) {
ret = poll(&pollfd, 1, -1);
if (ret == -1) {
printf("Failed to poll %s file (%d)\n",
brightness_file_path, ret);
ret = 1;
break;
}
clock_gettime(CLOCK_MONOTONIC, &ts);
ret = read(fd, buf, sizeof(buf));
if (ret < 0)
break;
ret = lseek(pollfd.fd, 0, SEEK_SET);
if (ret < 0) {
printf("lseek failed (%d)\n", ret);
break;
}
printf("[%ld.%09ld] %d\n", ts.tv_sec, ts.tv_nsec, atoi(buf));
}
close(fd);
return ret;
}
Markdown is supported
0% or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment