LED updates for 4.15rc1

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Merge tag 'leds_for_4.15rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/j.anaszewski/linux-leds

Pull LED updates from Jacek Anaszewski:
 "New LED class driver:
   - add a driver for PC Engines APU/APU2 LEDs

  New LED trigger:
   - add a system activity LED trigger

  LED core improvements:
   - replace flags bit shift with BIT() macros

  Convert timers to use timer_setup() in:
   - led-core
   - ledtrig-activity
   - ledtrig-heartbeat
   - ledtrig-transient

  LED class drivers fixes:
   - lp55xx: fix spelling mistake: 'cound' -> 'could'
   - tca6507: Remove unnecessary reg check
   - pca955x: Don't invert requested value in pca955x_gpio_set_value()

  LED documentation improvements:
   - update 00-INDEX file"

* tag 'leds_for_4.15rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/j.anaszewski/linux-leds:
  leds: Add driver for PC Engines APU/APU2 LEDs
  leds: lp55xx: fix spelling mistake: 'cound' -> 'could'
  leds: Convert timers to use timer_setup()
  Documentation: leds: Update 00-INDEX file
  leds: tca6507: Remove unnecessary reg check
  leds: ledtrig-heartbeat: Convert timers to use timer_setup()
  leds: Replace flags bit shift with BIT() macros
  leds: pca955x: Don't invert requested value in pca955x_gpio_set_value()
  leds: ledtrig-activity: Add a system activity LED trigger

Documentation/leds/00-INDEX

@@ -4,6 +4,10 @@ leds-blinkm.txt
 	- Driver for BlinkM LED-devices.
 leds-class.txt
 	- documents LED handling under Linux.
+leds-class-flash.txt
+	- documents flash LED handling under Linux.
+leds-lm3556.txt
+	- notes on how to use the leds-lm3556 driver.
 leds-lp3944.txt
 	- notes on how to use the leds-lp3944 driver.
 leds-lp5521.txt
@@ -16,7 +20,13 @@ leds-lp55xx.txt
 	- description about lp55xx common driver.
 leds-lm3556.txt
 	- notes on how to use the leds-lm3556 driver.
+leds-mlxcpld.txt
+	- notes on how to use the leds-mlxcpld driver.
 ledtrig-oneshot.txt
 	- One-shot LED trigger for both sporadic and dense events.
 ledtrig-transient.txt
 	- LED Transient Trigger, one shot timer activation.
+ledtrig-usbport.txt
+	- notes on how to use the drivers/usb/core/ledtrig-usbport.c trigger.
+uleds.txt
+	- notes on how to use the uleds driver.

drivers/leds/Kconfig

@@ -57,6 +57,16 @@ config LEDS_AAT1290
 	depends on PINCTRL
 	help
 	 This option enables support for the LEDs on the AAT1290.
+config LEDS_APU
+	tristate "Front panel LED support for PC Engines APU/APU2 boards"
+	depends on LEDS_CLASS
+	depends on X86 && DMI
+	help
+	  This driver makes the PC Engines APU/APU2 front panel LEDs
+	  accessible from userspace programs through the LED subsystem.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called leds-apu.
 
 config LEDS_AS3645A
 	tristate "AS3645A LED flash controller support"

drivers/leds/Makefile

@@ -9,6 +9,7 @@ obj-$(CONFIG_LEDS_TRIGGERS)		+= led-triggers.o
 # LED Platform Drivers
 obj-$(CONFIG_LEDS_88PM860X)		+= leds-88pm860x.o
 obj-$(CONFIG_LEDS_AAT1290)		+= leds-aat1290.o
+obj-$(CONFIG_LEDS_APU)			+= leds-apu.o
 obj-$(CONFIG_LEDS_AS3645A)		+= leds-as3645a.o
 obj-$(CONFIG_LEDS_BCM6328)		+= leds-bcm6328.o
 obj-$(CONFIG_LEDS_BCM6358)		+= leds-bcm6358.o

drivers/leds/led-core.c

@@ -45,9 +45,9 @@ static int __led_set_brightness_blocking(struct led_classdev *led_cdev,
 	return led_cdev->brightness_set_blocking(led_cdev, value);
 }
 
-static void led_timer_function(unsigned long data)
+static void led_timer_function(struct timer_list *t)
 {
-	struct led_classdev *led_cdev = (void *)data;
+	struct led_classdev *led_cdev = from_timer(led_cdev, t, blink_timer);
 	unsigned long brightness;
 	unsigned long delay;
 
@@ -178,8 +178,7 @@ void led_init_core(struct led_classdev *led_cdev)
 {
 	INIT_WORK(&led_cdev->set_brightness_work, set_brightness_delayed);
 
-	setup_timer(&led_cdev->blink_timer, led_timer_function,
+	timer_setup(&led_cdev->blink_timer, led_timer_function, 0);
-		    (unsigned long)led_cdev);
 }
 EXPORT_SYMBOL_GPL(led_init_core);
 

drivers/leds/leds-apu.c

@@ -0,0 +1,278 @@
+/*
+ * drivers/leds/leds-apu.c
+ * Copyright (C) 2017 Alan Mizrahi, alan at mizrahi dot com dot ve
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the names of the copyright holders nor the names of its
+ *    contributors may be used to endorse or promote products derived from
+ *    this software without specific prior written permission.
+ *
+ * Alternatively, this software may be distributed under the terms of the
+ * GNU General Public License ("GPL") version 2 as published by the Free
+ * Software Foundation.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <linux/dmi.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/leds.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+
+#define APU1_FCH_ACPI_MMIO_BASE 0xFED80000
+#define APU1_FCH_GPIO_BASE      (APU1_FCH_ACPI_MMIO_BASE + 0x01BD)
+#define APU1_LEDON              0x08
+#define APU1_LEDOFF             0xC8
+#define APU1_NUM_GPIO           3
+#define APU1_IOSIZE             sizeof(u8)
+
+#define APU2_FCH_ACPI_MMIO_BASE 0xFED80000
+#define APU2_FCH_GPIO_BASE      (APU2_FCH_ACPI_MMIO_BASE + 0x1500)
+#define APU2_GPIO_BIT_WRITE     22
+#define APU2_APU2_NUM_GPIO      4
+#define APU2_IOSIZE             sizeof(u32)
+
+/* LED access parameters */
+struct apu_param {
+	void __iomem *addr; /* for ioread/iowrite */
+};
+
+/* LED private data */
+struct apu_led_priv {
+	struct led_classdev cdev;
+	struct apu_param param;
+};
+#define cdev_to_priv(c) container_of(c, struct apu_led_priv, cdev)
+
+/* LED profile */
+struct apu_led_profile {
+	const char *name;
+	enum led_brightness brightness;
+	unsigned long offset; /* for devm_ioremap */
+};
+
+/* Supported platform types */
+enum apu_led_platform_types {
+	APU1_LED_PLATFORM,
+	APU2_LED_PLATFORM,
+};
+
+struct apu_led_pdata {
+	struct platform_device *pdev;
+	struct apu_led_priv *pled;
+	const struct apu_led_profile *profile;
+	enum apu_led_platform_types platform;
+	int num_led_instances;
+	int iosize; /* for devm_ioremap() */
+	spinlock_t lock;
+};
+
+static struct apu_led_pdata *apu_led;
+
+static const struct apu_led_profile apu1_led_profile[] = {
+	{ "apu:green:1", LED_ON,  APU1_FCH_GPIO_BASE + 0 * APU1_IOSIZE },
+	{ "apu:green:2", LED_OFF, APU1_FCH_GPIO_BASE + 1 * APU1_IOSIZE },
+	{ "apu:green:3", LED_OFF, APU1_FCH_GPIO_BASE + 2 * APU1_IOSIZE },
+};
+
+static const struct apu_led_profile apu2_led_profile[] = {
+	{ "apu2:green:1", LED_ON,  APU2_FCH_GPIO_BASE + 68 * APU2_IOSIZE },
+	{ "apu2:green:2", LED_OFF, APU2_FCH_GPIO_BASE + 69 * APU2_IOSIZE },
+	{ "apu2:green:3", LED_OFF, APU2_FCH_GPIO_BASE + 70 * APU2_IOSIZE },
+};
+
+static const struct dmi_system_id apu_led_dmi_table[] __initconst = {
+	{
+		.ident = "apu",
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "PC Engines"),
+			DMI_MATCH(DMI_PRODUCT_NAME, "APU")
+		}
+	},
+	{
+		.ident = "apu2",
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "PC Engines"),
+			DMI_MATCH(DMI_BOARD_NAME, "APU2")
+		}
+	},
+	{}
+};
+MODULE_DEVICE_TABLE(dmi, apu_led_dmi_table);
+
+static void apu1_led_brightness_set(struct led_classdev *led, enum led_brightness value)
+{
+	struct apu_led_priv *pled = cdev_to_priv(led);
+
+	spin_lock(&apu_led->lock);
+	iowrite8(value ? APU1_LEDON : APU1_LEDOFF, pled->param.addr);
+	spin_unlock(&apu_led->lock);
+}
+
+static void apu2_led_brightness_set(struct led_classdev *led, enum led_brightness value)
+{
+	struct apu_led_priv *pled = cdev_to_priv(led);
+	u32 value_new;
+
+	spin_lock(&apu_led->lock);
+
+	value_new = ioread32(pled->param.addr);
+
+	if (value)
+		value_new &= ~BIT(APU2_GPIO_BIT_WRITE);
+	else
+		value_new |= BIT(APU2_GPIO_BIT_WRITE);
+
+	iowrite32(value_new, pled->param.addr);
+
+	spin_unlock(&apu_led->lock);
+}
+
+static int apu_led_config(struct device *dev, struct apu_led_pdata *apuld)
+{
+	int i;
+	int err;
+
+	apu_led->pled = devm_kzalloc(dev,
+		sizeof(struct apu_led_priv) * apu_led->num_led_instances,
+		GFP_KERNEL);
+
+	if (!apu_led->pled)
+		return -ENOMEM;
+
+	for (i = 0; i < apu_led->num_led_instances; i++) {
+		struct apu_led_priv *pled = &apu_led->pled[i];
+		struct led_classdev *led_cdev = &pled->cdev;
+
+		led_cdev->name = apu_led->profile[i].name;
+		led_cdev->brightness = apu_led->profile[i].brightness;
+		led_cdev->max_brightness = 1;
+		led_cdev->flags = LED_CORE_SUSPENDRESUME;
+		if (apu_led->platform == APU1_LED_PLATFORM)
+			led_cdev->brightness_set = apu1_led_brightness_set;
+		else if (apu_led->platform == APU2_LED_PLATFORM)
+			led_cdev->brightness_set = apu2_led_brightness_set;
+
+		pled->param.addr = devm_ioremap(dev,
+				apu_led->profile[i].offset, apu_led->iosize);
+		if (!pled->param.addr) {
+			err = -ENOMEM;
+			goto error;
+		}
+
+		err = led_classdev_register(dev, led_cdev);
+		if (err)
+			goto error;
+
+		led_cdev->brightness_set(led_cdev, apu_led->profile[i].brightness);
+	}
+
+	return 0;
+
+error:
+	while (i-- > 0)
+		led_classdev_unregister(&apu_led->pled[i].cdev);
+
+	return err;
+}
+
+static int __init apu_led_probe(struct platform_device *pdev)
+{
+	apu_led = devm_kzalloc(&pdev->dev, sizeof(*apu_led), GFP_KERNEL);
+
+	if (!apu_led)
+		return -ENOMEM;
+
+	apu_led->pdev = pdev;
+
+	if (dmi_match(DMI_BOARD_NAME, "APU")) {
+		apu_led->profile = apu1_led_profile;
+		apu_led->platform = APU1_LED_PLATFORM;
+		apu_led->num_led_instances = ARRAY_SIZE(apu1_led_profile);
+		apu_led->iosize = APU1_IOSIZE;
+	} else if (dmi_match(DMI_BOARD_NAME, "APU2")) {
+		apu_led->profile = apu2_led_profile;
+		apu_led->platform = APU2_LED_PLATFORM;
+		apu_led->num_led_instances = ARRAY_SIZE(apu2_led_profile);
+		apu_led->iosize = APU2_IOSIZE;
+	}
+
+	spin_lock_init(&apu_led->lock);
+	return apu_led_config(&pdev->dev, apu_led);
+}
+
+static struct platform_driver apu_led_driver = {
+	.driver = {
+		.name = KBUILD_MODNAME,
+	},
+};
+
+static int __init apu_led_init(void)
+{
+	struct platform_device *pdev;
+	int err;
+
+	if (!dmi_match(DMI_SYS_VENDOR, "PC Engines")) {
+		pr_err("No PC Engines board detected\n");
+		return -ENODEV;
+	}
+	if (!(dmi_match(DMI_PRODUCT_NAME, "APU") || dmi_match(DMI_PRODUCT_NAME, "APU2"))) {
+		pr_err("Unknown PC Engines board: %s\n",
+				dmi_get_system_info(DMI_PRODUCT_NAME));
+		return -ENODEV;
+	}
+
+	pdev = platform_device_register_simple(KBUILD_MODNAME, -1, NULL, 0);
+	if (IS_ERR(pdev)) {
+		pr_err("Device allocation failed\n");
+		return PTR_ERR(pdev);
+	}
+
+	err = platform_driver_probe(&apu_led_driver, apu_led_probe);
+	if (err) {
+		pr_err("Probe platform driver failed\n");
+		platform_device_unregister(pdev);
+	}
+
+	return err;
+}
+
+static void __exit apu_led_exit(void)
+{
+	int i;
+
+	for (i = 0; i < apu_led->num_led_instances; i++)
+		led_classdev_unregister(&apu_led->pled[i].cdev);
+
+	platform_device_unregister(apu_led->pdev);
+	platform_driver_unregister(&apu_led_driver);
+}
+
+module_init(apu_led_init);
+module_exit(apu_led_exit);
+
+MODULE_AUTHOR("Alan Mizrahi");
+MODULE_DESCRIPTION("PC Engines APU family LED driver");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:leds_apu");

drivers/leds/leds-lp5523.c

@@ -323,7 +323,7 @@ static int lp5523_init_program_engine(struct lp55xx_chip *chip)
 
 	if (status != LP5523_ENG_STATUS_MASK) {
 		dev_err(&chip->cl->dev,
-			"cound not configure LED engine, status = 0x%.2x\n",
+			"could not configure LED engine, status = 0x%.2x\n",
 			status);
 		ret = -1;
 	}

drivers/leds/leds-pca955x.c

@@ -61,6 +61,10 @@
 #define PCA955X_LS_BLINK0	0x2	/* Blink at PWM0 rate */
 #define PCA955X_LS_BLINK1	0x3	/* Blink at PWM1 rate */
 
+#define PCA955X_GPIO_INPUT	LED_OFF
+#define PCA955X_GPIO_HIGH	LED_OFF
+#define PCA955X_GPIO_LOW	LED_FULL
+
 enum pca955x_type {
 	pca9550,
 	pca9551,
@@ -329,9 +333,9 @@ static int pca955x_set_value(struct gpio_chip *gc, unsigned int offset,
 	struct pca955x_led *led = &pca955x->leds[offset];
 
 	if (val)
-		return pca955x_led_set(&led->led_cdev, LED_FULL);
+		return pca955x_led_set(&led->led_cdev, PCA955X_GPIO_HIGH);
-	else
+
-		return pca955x_led_set(&led->led_cdev, LED_OFF);
+	return pca955x_led_set(&led->led_cdev, PCA955X_GPIO_LOW);
 }
 
 static void pca955x_gpio_set_value(struct gpio_chip *gc, unsigned int offset,
@@ -355,8 +359,11 @@ static int pca955x_gpio_get_value(struct gpio_chip *gc, unsigned int offset)
 static int pca955x_gpio_direction_input(struct gpio_chip *gc,
 					unsigned int offset)
 {
-	/* To use as input ensure pin is not driven */
+	struct pca955x *pca955x = gpiochip_get_data(gc);
-	return pca955x_set_value(gc, offset, 0);
+	struct pca955x_led *led = &pca955x->leds[offset];
+
+	/* To use as input ensure pin is not driven. */
+	return pca955x_led_set(&led->led_cdev, PCA955X_GPIO_INPUT);
 }
 
 static int pca955x_gpio_direction_output(struct gpio_chip *gc,

drivers/leds/leds-tca6507.c

@@ -715,7 +715,7 @@ tca6507_led_dt_init(struct i2c_client *client)
 		if (of_property_match_string(child, "compatible", "gpio") >= 0)
 			led.flags |= TCA6507_MAKE_GPIO;
 		ret = of_property_read_u32(child, "reg", &reg);
-		if (ret != 0 || reg < 0 || reg >= NUM_LEDS)
+		if (ret != 0 || reg >= NUM_LEDS)
 			continue;
 
 		tca_leds[reg] = led;

drivers/leds/trigger/Kconfig

@@ -77,6 +77,15 @@ config LEDS_TRIGGER_CPU
 
 	  If unsure, say N.
 
+config LEDS_TRIGGER_ACTIVITY
+	tristate "LED activity Trigger"
+	depends on LEDS_TRIGGERS
+	help
+	  This allows LEDs to be controlled by a immediate CPU usage.
+	  The flash frequency and duty cycle varies from faint flashes to
+	  intense brightness depending on the instant CPU load.
+	  If unsure, say N.
+
 config LEDS_TRIGGER_GPIO
 	tristate "LED GPIO Trigger"
 	depends on LEDS_TRIGGERS

drivers/leds/trigger/Makefile

@@ -7,6 +7,7 @@ obj-$(CONFIG_LEDS_TRIGGER_HEARTBEAT)	+= ledtrig-heartbeat.o
 obj-$(CONFIG_LEDS_TRIGGER_BACKLIGHT)	+= ledtrig-backlight.o
 obj-$(CONFIG_LEDS_TRIGGER_GPIO)		+= ledtrig-gpio.o
 obj-$(CONFIG_LEDS_TRIGGER_CPU)		+= ledtrig-cpu.o
+obj-$(CONFIG_LEDS_TRIGGER_ACTIVITY)	+= ledtrig-activity.o
 obj-$(CONFIG_LEDS_TRIGGER_DEFAULT_ON)	+= ledtrig-default-on.o
 obj-$(CONFIG_LEDS_TRIGGER_TRANSIENT)	+= ledtrig-transient.o
 obj-$(CONFIG_LEDS_TRIGGER_CAMERA)	+= ledtrig-camera.o

drivers/leds/trigger/ledtrig-activity.c

@@ -0,0 +1,275 @@
+/*
+ * Activity LED trigger
+ *
+ * Copyright (C) 2017 Willy Tarreau <w@1wt.eu>
+ * Partially based on Atsushi Nemoto's ledtrig-heartbeat.c.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ */
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/kernel_stat.h>
+#include <linux/leds.h>
+#include <linux/module.h>
+#include <linux/reboot.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/timer.h>
+#include "../leds.h"
+
+static int panic_detected;
+
+struct activity_data {
+	struct timer_list timer;
+	struct led_classdev *led_cdev;
+	u64 last_used;
+	u64 last_boot;
+	int time_left;
+	int state;
+	int invert;
+};
+
+static void led_activity_function(struct timer_list *t)
+{
+	struct activity_data *activity_data = from_timer(activity_data, t,
+							 timer);
+	struct led_classdev *led_cdev = activity_data->led_cdev;
+	struct timespec boot_time;
+	unsigned int target;
+	unsigned int usage;
+	int delay;
+	u64 curr_used;
+	u64 curr_boot;
+	s32 diff_used;
+	s32 diff_boot;
+	int cpus;
+	int i;
+
+	if (test_and_clear_bit(LED_BLINK_BRIGHTNESS_CHANGE, &led_cdev->work_flags))
+		led_cdev->blink_brightness = led_cdev->new_blink_brightness;
+
+	if (unlikely(panic_detected)) {
+		/* full brightness in case of panic */
+		led_set_brightness_nosleep(led_cdev, led_cdev->blink_brightness);
+		return;
+	}
+
+	get_monotonic_boottime(&boot_time);
+
+	cpus = 0;
+	curr_used = 0;
+
+	for_each_possible_cpu(i) {
+		curr_used += kcpustat_cpu(i).cpustat[CPUTIME_USER]
+			  +  kcpustat_cpu(i).cpustat[CPUTIME_NICE]
+			  +  kcpustat_cpu(i).cpustat[CPUTIME_SYSTEM]
+			  +  kcpustat_cpu(i).cpustat[CPUTIME_SOFTIRQ]
+			  +  kcpustat_cpu(i).cpustat[CPUTIME_IRQ];
+		cpus++;
+	}
+
+	/* We come here every 100ms in the worst case, so that's 100M ns of
+	 * cumulated time. By dividing by 2^16, we get the time resolution
+	 * down to 16us, ensuring we won't overflow 32-bit computations below
+	 * even up to 3k CPUs, while keeping divides cheap on smaller systems.
+	 */
+	curr_boot = timespec_to_ns(&boot_time) * cpus;
+	diff_boot = (curr_boot - activity_data->last_boot) >> 16;
+	diff_used = (curr_used - activity_data->last_used) >> 16;
+	activity_data->last_boot = curr_boot;
+	activity_data->last_used = curr_used;
+
+	if (diff_boot <= 0 || diff_used < 0)
+		usage = 0;
+	else if (diff_used >= diff_boot)
+		usage = 100;
+	else
+		usage = 100 * diff_used / diff_boot;
+
+	/*
+	 * Now we know the total boot_time multiplied by the number of CPUs, and
+	 * the total idle+wait time for all CPUs. We'll compare how they evolved
+	 * since last call. The % of overall CPU usage is :
+	 *
+	 *      1 - delta_idle / delta_boot
+	 *
+	 * What we want is that when the CPU usage is zero, the LED must blink
+	 * slowly with very faint flashes that are detectable but not disturbing
+	 * (typically 10ms every second, or 10ms ON, 990ms OFF). Then we want
+	 * blinking frequency to increase up to the point where the load is
+	 * enough to saturate one core in multi-core systems or 50% in single
+	 * core systems. At this point it should reach 10 Hz with a 10/90 duty
+	 * cycle (10ms ON, 90ms OFF). After this point, the blinking frequency
+	 * remains stable (10 Hz) and only the duty cycle increases to report
+	 * the activity, up to the point where we have 90ms ON, 10ms OFF when
+	 * all cores are saturated. It's important that the LED never stays in
+	 * a steady state so that it's easy to distinguish an idle or saturated
+	 * machine from a hung one.
+	 *
+	 * This gives us :
+	 *   - a target CPU usage of min(50%, 100%/#CPU) for a 10% duty cycle
+	 *     (10ms ON, 90ms OFF)
+	 *   - below target :
+	 *      ON_ms  = 10
+	 *      OFF_ms = 90 + (1 - usage/target) * 900
+	 *   - above target :
+	 *      ON_ms  = 10 + (usage-target)/(100%-target) * 80
+	 *      OFF_ms = 90 - (usage-target)/(100%-target) * 80
+	 *
+	 * In order to keep a good responsiveness, we cap the sleep time to
+	 * 100 ms and keep track of the sleep time left. This allows us to
+	 * quickly change it if needed.
+	 */
+
+	activity_data->time_left -= 100;
+	if (activity_data->time_left <= 0) {
+		activity_data->time_left = 0;
+		activity_data->state = !activity_data->state;
+		led_set_brightness_nosleep(led_cdev,
+			(activity_data->state ^ activity_data->invert) ?
+			led_cdev->blink_brightness : LED_OFF);
+	}
+
+	target = (cpus > 1) ? (100 / cpus) : 50;
+
+	if (usage < target)
+		delay = activity_data->state ?
+			10 :                        /* ON  */
+			990 - 900 * usage / target; /* OFF */
+	else
+		delay = activity_data->state ?
+			10 + 80 * (usage - target) / (100 - target) : /* ON  */
+			90 - 80 * (usage - target) / (100 - target);  /* OFF */
+
+
+	if (!activity_data->time_left || delay <= activity_data->time_left)
+		activity_data->time_left = delay;
+
+	delay = min_t(int, activity_data->time_left, 100);
+	mod_timer(&activity_data->timer, jiffies + msecs_to_jiffies(delay));
+}
+
+static ssize_t led_invert_show(struct device *dev,
+                               struct device_attribute *attr, char *buf)
+{
+	struct led_classdev *led_cdev = dev_get_drvdata(dev);
+	struct activity_data *activity_data = led_cdev->trigger_data;
+
+	return sprintf(buf, "%u\n", activity_data->invert);
+}
+
+static ssize_t led_invert_store(struct device *dev,
+                                struct device_attribute *attr,
+                                const char *buf, size_t size)
+{
+	struct led_classdev *led_cdev = dev_get_drvdata(dev);
+	struct activity_data *activity_data = led_cdev->trigger_data;
+	unsigned long state;
+	int ret;
+
+	ret = kstrtoul(buf, 0, &state);
+	if (ret)
+		return ret;
+
+	activity_data->invert = !!state;
+
+	return size;
+}
+
+static DEVICE_ATTR(invert, 0644, led_invert_show, led_invert_store);
+
+static void activity_activate(struct led_classdev *led_cdev)
+{
+	struct activity_data *activity_data;
+	int rc;
+
+	activity_data = kzalloc(sizeof(*activity_data), GFP_KERNEL);
+	if (!activity_data)
+		return;
+
+	led_cdev->trigger_data = activity_data;
+	rc = device_create_file(led_cdev->dev, &dev_attr_invert);
+	if (rc) {
+		kfree(led_cdev->trigger_data);
+		return;
+	}
+
+	activity_data->led_cdev = led_cdev;
+	timer_setup(&activity_data->timer, led_activity_function, 0);
+	if (!led_cdev->blink_brightness)
+		led_cdev->blink_brightness = led_cdev->max_brightness;
+	led_activity_function(&activity_data->timer);
+	set_bit(LED_BLINK_SW, &led_cdev->work_flags);
+	led_cdev->activated = true;
+}
+
+static void activity_deactivate(struct led_classdev *led_cdev)
+{
+	struct activity_data *activity_data = led_cdev->trigger_data;
+
+	if (led_cdev->activated) {
+		del_timer_sync(&activity_data->timer);
+		device_remove_file(led_cdev->dev, &dev_attr_invert);
+		kfree(activity_data);
+		clear_bit(LED_BLINK_SW, &led_cdev->work_flags);
+		led_cdev->activated = false;
+	}
+}
+
+static struct led_trigger activity_led_trigger = {
+	.name       = "activity",
+	.activate   = activity_activate,
+	.deactivate = activity_deactivate,
+};
+
+static int activity_reboot_notifier(struct notifier_block *nb,
+                                    unsigned long code, void *unused)
+{
+	led_trigger_unregister(&activity_led_trigger);
+	return NOTIFY_DONE;
+}
+
+static int activity_panic_notifier(struct notifier_block *nb,
+                                   unsigned long code, void *unused)
+{
+	panic_detected = 1;
+	return NOTIFY_DONE;
+}
+
+static struct notifier_block activity_reboot_nb = {
+	.notifier_call = activity_reboot_notifier,
+};
+
+static struct notifier_block activity_panic_nb = {
+	.notifier_call = activity_panic_notifier,
+};
+
+static int __init activity_init(void)
+{
+	int rc = led_trigger_register(&activity_led_trigger);
+
+	if (!rc) {
+		atomic_notifier_chain_register(&panic_notifier_list,
+					       &activity_panic_nb);
+		register_reboot_notifier(&activity_reboot_nb);
+	}
+	return rc;
+}
+
+static void __exit activity_exit(void)
+{
+	unregister_reboot_notifier(&activity_reboot_nb);
+	atomic_notifier_chain_unregister(&panic_notifier_list,
+					 &activity_panic_nb);
+	led_trigger_unregister(&activity_led_trigger);
+}
+
+module_init(activity_init);
+module_exit(activity_exit);
+
+MODULE_AUTHOR("Willy Tarreau <w@1wt.eu>");
+MODULE_DESCRIPTION("Activity LED trigger");
+MODULE_LICENSE("GPL");

drivers/leds/trigger/ledtrig-heartbeat.c

@@ -25,19 +25,23 @@
 static int panic_heartbeats;
 
 struct heartbeat_trig_data {
+	struct led_classdev *led_cdev;
 	unsigned int phase;
 	unsigned int period;
 	struct timer_list timer;
 	unsigned int invert;
 };
 
-static void led_heartbeat_function(unsigned long data)
+static void led_heartbeat_function(struct timer_list *t)
 {
-	struct led_classdev *led_cdev = (struct led_classdev *) data;
+	struct heartbeat_trig_data *heartbeat_data =
-	struct heartbeat_trig_data *heartbeat_data = led_cdev->trigger_data;
+		from_timer(heartbeat_data, t, timer);
+	struct led_classdev *led_cdev;
 	unsigned long brightness = LED_OFF;
 	unsigned long delay = 0;
 
+	led_cdev = heartbeat_data->led_cdev;
+
 	if (unlikely(panic_heartbeats)) {
 		led_set_brightness_nosleep(led_cdev, LED_OFF);
 		return;
@@ -127,18 +131,18 @@ static void heartbeat_trig_activate(struct led_classdev *led_cdev)
 		return;
 
 	led_cdev->trigger_data = heartbeat_data;
+	heartbeat_data->led_cdev = led_cdev;
 	rc = device_create_file(led_cdev->dev, &dev_attr_invert);
 	if (rc) {
 		kfree(led_cdev->trigger_data);
 		return;
 	}
 
-	setup_timer(&heartbeat_data->timer,
+	timer_setup(&heartbeat_data->timer, led_heartbeat_function, 0);
-		    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);
+	led_heartbeat_function(&heartbeat_data->timer);
 	set_bit(LED_BLINK_SW, &led_cdev->work_flags);
 	led_cdev->activated = true;
 }

drivers/leds/trigger/ledtrig-transient.c

@@ -33,12 +33,14 @@ struct transient_trig_data {
 	int restore_state;
 	unsigned long duration;
 	struct timer_list timer;
+	struct led_classdev *led_cdev;
 };
 
-static void transient_timer_function(unsigned long data)
+static void transient_timer_function(struct timer_list *t)
 {
-	struct led_classdev *led_cdev = (struct led_classdev *) data;
+	struct transient_trig_data *transient_data =
-	struct transient_trig_data *transient_data = led_cdev->trigger_data;
+		from_timer(transient_data, t, timer);
+	struct led_classdev *led_cdev = transient_data->led_cdev;
 
 	transient_data->activate = 0;
 	led_set_brightness_nosleep(led_cdev, transient_data->restore_state);
@@ -169,6 +171,7 @@ static void transient_trig_activate(struct led_classdev *led_cdev)
 		return;
 	}
 	led_cdev->trigger_data = tdata;
+	tdata->led_cdev = led_cdev;
 
 	rc = device_create_file(led_cdev->dev, &dev_attr_activate);
 	if (rc)
@@ -182,8 +185,7 @@ static void transient_trig_activate(struct led_classdev *led_cdev)
 	if (rc)
 		goto err_out_state;
 
-	setup_timer(&tdata->timer, transient_timer_function,
+	timer_setup(&tdata->timer, transient_timer_function, 0);
-		    (unsigned long) led_cdev);
 	led_cdev->activated = true;
 
 	return;

include/linux/leds.h

@@ -40,16 +40,16 @@ struct led_classdev {
 	int			 flags;
 
 	/* Lower 16 bits reflect status */
-#define LED_SUSPENDED		(1 << 0)
+#define LED_SUSPENDED		BIT(0)
-#define LED_UNREGISTERING	(1 << 1)
+#define LED_UNREGISTERING	BIT(1)
 	/* Upper 16 bits reflect control information */
-#define LED_CORE_SUSPENDRESUME	(1 << 16)
+#define LED_CORE_SUSPENDRESUME	BIT(16)
-#define LED_SYSFS_DISABLE	(1 << 17)
+#define LED_SYSFS_DISABLE	BIT(17)
-#define LED_DEV_CAP_FLASH	(1 << 18)
+#define LED_DEV_CAP_FLASH	BIT(18)
-#define LED_HW_PLUGGABLE	(1 << 19)
+#define LED_HW_PLUGGABLE	BIT(19)
-#define LED_PANIC_INDICATOR	(1 << 20)
+#define LED_PANIC_INDICATOR	BIT(20)
-#define LED_BRIGHT_HW_CHANGED	(1 << 21)
+#define LED_BRIGHT_HW_CHANGED	BIT(21)
-#define LED_RETAIN_AT_SHUTDOWN	(1 << 22)
+#define LED_RETAIN_AT_SHUTDOWN	BIT(22)
 
 	/* set_brightness_work / blink_timer flags, atomic, private. */
 	unsigned long		work_flags;