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
diff --git a/Documentation/ABI/testing/sysfs-class-led b/Documentation/ABI/testing/sysfs-class-led
index 491cdee..5f67f7a 100644
--- a/Documentation/ABI/testing/sysfs-class-led
+++ b/Documentation/ABI/testing/sysfs-class-led
@@ -23,6 +23,23 @@
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
diff --git a/Documentation/devicetree/bindings/leds/common.txt b/Documentation/devicetree/bindings/leds/common.txt
index 696be57..24b6560 100644
--- a/Documentation/devicetree/bindings/leds/common.txt
+++ b/Documentation/devicetree/bindings/leds/common.txt
@@ -61,16 +61,24 @@
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>;
+ };
};
diff --git a/Documentation/leds/leds-class.txt b/Documentation/leds/leds-class.txt
index f1f7ec9..836cb16 100644
--- a/Documentation/leds/leds-class.txt
+++ b/Documentation/leds/leds-class.txt
@@ -65,6 +65,21 @@
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 c621cbb..275f467 100644
--- a/drivers/leds/Kconfig
+++ b/drivers/leds/Kconfig
@@ -29,6 +29,15 @@
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 326ee6e..f2b0a80 100644
--- a/drivers/leds/led-class.c
+++ b/drivers/leds/led-class.c
@@ -103,6 +103,68 @@
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.
@@ -204,10 +266,21 @@
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 */
down_write(&leds_list_lock);
@@ -256,6 +329,9 @@
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/drivers/leds/leds-ktd2692.c b/drivers/leds/leds-ktd2692.c
index bf23ba1..45296aa 100644
--- a/drivers/leds/leds-ktd2692.c
+++ b/drivers/leds/leds-ktd2692.c
@@ -270,15 +270,15 @@
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;
}
diff --git a/drivers/leds/trigger/ledtrig-heartbeat.c b/drivers/leds/trigger/ledtrig-heartbeat.c
index c9f3862..e6f2f8b 100644
--- a/drivers/leds/trigger/ledtrig-heartbeat.c
+++ b/drivers/leds/trigger/ledtrig-heartbeat.c
@@ -43,6 +43,9 @@
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 @@
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 @@
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 @@
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;
}
}
diff --git a/include/linux/leds.h b/include/linux/leds.h
index 569cb53..38c0bd7 100644
--- a/include/linux/leds.h
+++ b/include/linux/leds.h
@@ -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 @@
enum led_brightness {
LED_OFF = 0,
+ LED_ON = 1,
LED_HALF = 127,
LED_FULL = 255,
};
@@ -46,6 +48,7 @@
#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 @@
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 @@
}
#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 */
diff --git a/tools/leds/Makefile b/tools/leds/Makefile
index c03a79e..078b666 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 0000000..64642cc
--- /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 <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;
+}
