From e64b8cc72bf9958efd4f38e55d2980c95e0ce679 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= Date: Tue, 6 Dec 2016 09:32:03 +0100 Subject: [PATCH 1/6] DT: leds: Improve examples by adding some context MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit During my work on some new LED trigger I tried adding example similar to the existing ones which received following comment from Rob: > It's not really clear in the example this is an LED node as it is > incomplete. Keeping that in mind I suggest adding context for the existing example entries in hope to make documentation more clear. Signed-off-by: Rafał Miłecki Signed-off-by: Jacek Anaszewski --- .../devicetree/bindings/leds/common.txt | 28 ++++++++++++------- 1 file changed, 18 insertions(+), 10 deletions(-) diff --git a/Documentation/devicetree/bindings/leds/common.txt b/Documentation/devicetree/bindings/leds/common.txt index 696be5792625..24b656014089 100644 --- a/Documentation/devicetree/bindings/leds/common.txt +++ b/Documentation/devicetree/bindings/leds/common.txt @@ -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>; + }; }; From 4e552c8cb5bc9137e67e035bab8df6dddbca7384 Mon Sep 17 00:00:00 2001 From: Andi Shyti Date: Thu, 5 Jan 2017 11:34:12 +0900 Subject: [PATCH 2/6] leds: add LED_ON brightness as boolean value Some devices do not handle the led brightness or simply don't care about it. Conceptually said devices want to just switch on or off the led. It is useless in this case to have a 255 range of brightness, while just having an LED_ON and LED_OFF improves the boolean meaning of the led status. Signed-off-by: Andi Shyti Acked-by: Pavel Machek Signed-off-by: Jacek Anaszewski --- include/linux/leds.h | 1 + 1 file changed, 1 insertion(+) diff --git a/include/linux/leds.h b/include/linux/leds.h index 569cb531094c..bb50d0151e75 100644 --- a/include/linux/leds.h +++ b/include/linux/leds.h @@ -27,6 +27,7 @@ struct device; enum led_brightness { LED_OFF = 0, + LED_ON = 1, LED_HALF = 127, LED_FULL = 255, }; From cbe99c538d1776009e8710755bb6e726f7fffa9b Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Wed, 25 Jan 2017 23:22:36 +0100 Subject: [PATCH 3/6] leds: ktd2692: avoid harmless maybe-uninitialized warning gcc gets confused about the control flow in ktd2692_parse_dt(), causing it to warn about what seems like a potential bug: drivers/leds/leds-ktd2692.c: In function 'ktd2692_probe': drivers/leds/leds-ktd2692.c:244:15: error: '*((void *)&led_cfg+8)' may be used uninitialized in this function [-Werror=maybe-uninitialized] drivers/leds/leds-ktd2692.c:225:7: error: 'led_cfg.flash_max_microamp' may be used uninitialized in this function [-Werror=maybe-uninitialized] drivers/leds/leds-ktd2692.c:232:3: error: 'led_cfg.movie_max_microamp' may be used uninitialized in this function [-Werror=maybe-uninitialized] The code is fine, and slightly reworking it in an equivalent way lets gcc figure that out too, which gets rid of the warning. Fixes: 77e7915b15bb ("leds: ktd2692: Add missing of_node_put") Signed-off-by: Arnd Bergmann Acked-by: Pavel Machek Signed-off-by: Jacek Anaszewski --- drivers/leds/leds-ktd2692.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/drivers/leds/leds-ktd2692.c b/drivers/leds/leds-ktd2692.c index bf23ba191ad0..45296aaca9da 100644 --- a/drivers/leds/leds-ktd2692.c +++ b/drivers/leds/leds-ktd2692.c @@ -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; } From 0cb8eb30d425d2d2ae28ab630596c44a158784c4 Mon Sep 17 00:00:00 2001 From: Hans de Goede Date: Sun, 29 Jan 2017 14:42:52 +0100 Subject: [PATCH 4/6] leds: class: Add new optional brightness_hw_changed attribute Some LEDs may have their brightness level changed autonomously (outside of kernel control) by hardware / firmware. This commit adds support for an optional brightness_hw_changed attribute to signal such changes to userspace (if a driver can detect them): What: /sys/class/leds//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. Drivers which want to support this, simply add LED_BRIGHT_HW_CHANGED to their flags field and call led_classdev_notify_brightness_hw_changed() with the hardware set brightness when they detect a hardware / firmware triggered brightness change. Signed-off-by: Hans de Goede Acked-by: Pavel Machek Signed-off-by: Jacek Anaszewski --- Documentation/ABI/testing/sysfs-class-led | 17 +++++ Documentation/leds/leds-class.txt | 15 +++++ drivers/leds/Kconfig | 9 +++ drivers/leds/led-class.c | 76 +++++++++++++++++++++++ include/linux/leds.h | 15 +++++ 5 files changed, 132 insertions(+) diff --git a/Documentation/ABI/testing/sysfs-class-led b/Documentation/ABI/testing/sysfs-class-led index 491cdeedc195..5f67f7ab277b 100644 --- a/Documentation/ABI/testing/sysfs-class-led +++ b/Documentation/ABI/testing/sysfs-class-led @@ -23,6 +23,23 @@ Description: If the LED does not support different brightness levels, this should be 1. +What: /sys/class/leds//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//trigger Date: March 2006 KernelVersion: 2.6.17 diff --git a/Documentation/leds/leds-class.txt b/Documentation/leds/leds-class.txt index f1f7ec9f5cc5..836cb16d6f09 100644 --- a/Documentation/leds/leds-class.txt +++ b/Documentation/leds/leds-class.txt @@ -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 ================================== diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig index c621cbbb5768..275f467956ee 100644 --- a/drivers/leds/Kconfig +++ b/drivers/leds/Kconfig @@ -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 diff --git a/drivers/leds/led-class.c b/drivers/leds/led-class.c index 326ee6e925a2..f2b0a80a62b4 100644 --- a/drivers/leds/led-class.c +++ b/drivers/leds/led-class.c @@ -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); diff --git a/include/linux/leds.h b/include/linux/leds.h index bb50d0151e75..38c0bd7ca107 100644 --- a/include/linux/leds.h +++ b/include/linux/leds.h @@ -13,6 +13,7 @@ #define __LINUX_LEDS_H_INCLUDED #include +#include #include #include #include @@ -47,6 +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; @@ -111,6 +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; }; @@ -423,4 +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 */ From ae3473231e77a3f1909d48cd144cebe5e1d049b3 Mon Sep 17 00:00:00 2001 From: Jacek Anaszewski Date: Sun, 29 Jan 2017 12:52:31 +0100 Subject: [PATCH 5/6] tools/leds: Add led_hw_brightness_mon program LED subsystem supports POLLPRI on "brightness_hw_changed" sysfs file of LED class devices. This tool demonstrates how to use the feature. Signed-off-by: Jacek Anaszewski Acked-by: Hans de Goede Acked-by: Pavel Machek --- tools/leds/Makefile | 4 +- tools/leds/led_hw_brightness_mon.c | 84 ++++++++++++++++++++++++++++++ 2 files changed, 86 insertions(+), 2 deletions(-) create mode 100644 tools/leds/led_hw_brightness_mon.c diff --git a/tools/leds/Makefile b/tools/leds/Makefile index c03a79ebf9c8..078b666fd78b 100644 --- a/tools/leds/Makefile +++ b/tools/leds/Makefile @@ -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 diff --git a/tools/leds/led_hw_brightness_mon.c b/tools/leds/led_hw_brightness_mon.c new file mode 100644 index 000000000000..64642ccfe442 --- /dev/null +++ b/tools/leds/led_hw_brightness_mon.c @@ -0,0 +1,84 @@ +/* + * 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 + * + * is the name of the LED class device to be monitored. Pressing + * CTRL+C will exit. + */ + +#include +#include +#include +#include +#include +#include +#include +#include + +#include + +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 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; +} From fb3d769173d26268d7bf068094a599bb28b2ac63 Mon Sep 17 00:00:00 2001 From: Jacek Anaszewski Date: Wed, 9 Nov 2016 11:43:46 +0100 Subject: [PATCH 6/6] leds: ledtrig-heartbeat: Make top brightness adjustable LED class heartbeat trigger allowed only for blinking with max_brightness value. This patch adds more flexibility by exploiting part of LED core software blink infrastructure. Signed-off-by: Jacek Anaszewski Acked-by: Pavel Machek Reviewed-by: Hans de Goede --- drivers/leds/trigger/ledtrig-heartbeat.c | 15 +++++++++++---- 1 file changed, 11 insertions(+), 4 deletions(-) diff --git a/drivers/leds/trigger/ledtrig-heartbeat.c b/drivers/leds/trigger/ledtrig-heartbeat.c index c9f386213e9e..e6f2f8b9f09a 100644 --- a/drivers/leds/trigger/ledtrig-heartbeat.c +++ b/drivers/leds/trigger/ledtrig-heartbeat.c @@ -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; } }