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authorStephen Rothwell <sfr@canb.auug.org.au>2017-02-09 14:53:35 +1100
committerStephen Rothwell <sfr@canb.auug.org.au>2017-02-09 14:53:35 +1100
commit904f8b0174a37cc10f97b5517e20911f762887a5 (patch)
tree59a89c846cd8692b472efdfc7fd7aeeaf56d2591 /Documentation
parent3af0212130665293c2610050e68d71fc3cfaf237 (diff)
parent8bb1de680dac8bcd8a1d60be12080bb9b89c16d0 (diff)
Merge remote-tracking branch 'leds/for-next'
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/ABI/testing/sysfs-class-led17
-rw-r--r--Documentation/devicetree/bindings/leds/common.txt28
-rw-r--r--Documentation/leds/leds-class.txt15
3 files changed, 50 insertions, 10 deletions
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/<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 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>;
+ };
};
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
==================================