diff options
Diffstat (limited to 'target/linux/bcm27xx/patches-5.10/950-0507-overlays-gpio-led-new-overlay.patch')
| -rw-r--r-- | target/linux/bcm27xx/patches-5.10/950-0507-overlays-gpio-led-new-overlay.patch | 191 |
1 files changed, 191 insertions, 0 deletions
diff --git a/target/linux/bcm27xx/patches-5.10/950-0507-overlays-gpio-led-new-overlay.patch b/target/linux/bcm27xx/patches-5.10/950-0507-overlays-gpio-led-new-overlay.patch new file mode 100644 index 0000000000..0450e26bbf --- /dev/null +++ b/target/linux/bcm27xx/patches-5.10/950-0507-overlays-gpio-led-new-overlay.patch @@ -0,0 +1,191 @@ +From 095bad7f310809a951735d03be9d06938524a6bc Mon Sep 17 00:00:00 2001 +From: Assaf Gordon <assafgordon@gmail.com> +Date: Fri, 12 Mar 2021 00:13:07 -0700 +Subject: [PATCH] overlays: gpio-led: new overlay + +Add generic connection between the kernel's LED framework and +RPI's GPIO pins. + +Signed-off-by: Assaf Gordon <assafgordon@gmail.com> +--- + arch/arm/boot/dts/overlays/Makefile | 1 + + arch/arm/boot/dts/overlays/README | 56 +++++++++++ + .../boot/dts/overlays/gpio-led-overlay.dts | 97 +++++++++++++++++++ + 3 files changed, 154 insertions(+) + create mode 100755 arch/arm/boot/dts/overlays/gpio-led-overlay.dts + +--- a/arch/arm/boot/dts/overlays/Makefile ++++ b/arch/arm/boot/dts/overlays/Makefile +@@ -54,6 +54,7 @@ dtbo-$(CONFIG_ARCH_BCM2835) += \ + gpio-ir.dtbo \ + gpio-ir-tx.dtbo \ + gpio-key.dtbo \ ++ gpio-led.dtbo \ + gpio-no-bank0-irq.dtbo \ + gpio-no-irq.dtbo \ + gpio-poweroff.dtbo \ +--- a/arch/arm/boot/dts/overlays/README ++++ b/arch/arm/boot/dts/overlays/README +@@ -914,6 +914,62 @@ Params: gpio GPIO pin + keycode Set the key code for the button + + ++ ++Name: gpio-led ++Info: This is a generic overlay for activating LEDs (or any other component) ++ by a GPIO pin. Multiple LEDs can be set up using multiple calls to the ++ overlay. While there are many existing methods to activate LEDs on the ++ RPi, this method offers some advantages: ++ 1) Does not require any userspace programs. ++ 2) LEDs can be connected to the kernel's led-trigger framework, ++ and drive the LED based on triggers such as cpu load, heartbeat, ++ kernel panic, key input, timers and others. ++ 3) LED can be tied to the input state of another GPIO pin. ++ 4) The LED is setup early during the kernel boot process (useful ++ for cpu/heartbeat/panic triggers). ++ ++ Typical electrical connection is: ++ RPI-GPIO.19 -> LED -> 300ohm resister -> RPI-GND ++ The GPIO pin number can be changed with the 'gpio=' parameter. ++ ++ To control an LED from userspace, write a 0 or 1 value: ++ echo 1 > /sys/class/leds/myled1/brightness ++ The 'myled1' name can be changed with the 'label=' parameter. ++ ++ To connect the LED to a kernel trigger from userspace: ++ echo cpu > /sys/class/leds/myled1/trigger ++ echo heartbeat > /sys/class/leds/myled1/trigger ++ echo none > /sys/class/leds/myled1/trigger ++ To connect the LED to GPIO.26 pin (physical pin 37): ++ echo gpio > /sys/class/leds/myled1/trigger ++ echo 26 > /sys/class/leds/myled1/gpio ++ Available triggers: ++ cat /sys/class/leds/myled1/trigger ++ ++ More information about the Linux kernel LED/Trigger system: ++ https://www.kernel.org/doc/Documentation/leds/leds-class.rst ++ https://www.kernel.org/doc/Documentation/leds/ledtrig-oneshot.rst ++Load: dtoverlay=gpio-led,<param>=<val> ++Params: gpio GPIO pin connected to the LED (default 19) ++ label The label for this LED. It will appear under ++ /sys/class/leds/<label> . Default 'myled1'. ++ trigger Set the led-trigger to connect to this LED. ++ default 'none' (LED is user-controlled). ++ Some possible triggers: ++ cpu - CPU load (all CPUs) ++ cpu0 - CPU load of first CPU. ++ mmc - disk activity (all disks) ++ panic - turn on on kernel panic ++ heartbeat - indicate system health ++ gpio - connect to a GPIO input pin (note: ++ currently the GPIO PIN can not be set ++ using overlay parameters, must be ++ done in userspace, see examples above. ++ active_low Set to 1 to turn invert the LED control ++ (writing 0 to /sys/class/leds/XXX/brightness ++ will turn on the GPIO/LED). Default '0'. ++ ++ + Name: gpio-no-bank0-irq + Info: Use this overlay to disable GPIO interrupts for GPIOs in bank 0 (0-27), + which can be useful for UIO drivers. +--- /dev/null ++++ b/arch/arm/boot/dts/overlays/gpio-led-overlay.dts +@@ -0,0 +1,97 @@ ++// SPDX-License-Identifier: GPL-2.0-or-later ++/* ++ * gpio-led - generic connection of kernel's LED framework to the RPI's GPIO. ++ * Copyright (C) 2021 House Gordon Software Company Ltd. <assafgordon@gmail.com> ++ * ++ * Based on information from: ++ * https://mjoldfield.com/atelier/2017/03/rpi-devicetree.html ++ * https://www.raspberrypi.org/documentation/configuration/device-tree.md ++ * https://www.kernel.org/doc/html/latest/leds/index.html ++ * ++ * compile with: ++ * dtc -@ -Hepapr -I dts -O dtb -o gpio-led.dtbo gpio-led-overlay.dts ++ * ++ * There will be some warnings (can be ignored): ++ * Warning (label_is_string): /__overrides__:label: property is not a string ++ * Warning (unit_address_vs_reg): /fragment@0/__overlay__/led_pins@0: ++ * node has a unit name, but no reg property ++ * Warning (unit_address_vs_reg): /fragment@1/__overlay__/leds@0: ++ * node has a unit name, but no reg property ++ * Warning (gpios_property): /__overrides__: Missing property ++ * '#gpio-cells' in node /fragment@1/__overlay__/leds@0/led ++ * or bad phandle (referred from gpio[0]) ++ * ++ * Typical electrical connection is: ++ * RPI-GPIO.19 -> LED -> 300ohm resister -> RPI-GND ++ * The GPIO pin number can be changed with the 'gpio=' parameter. ++ * ++ * Test from user-space with: ++ * # if nothing is shown, the overlay file isn't found in /boot/overlays ++ * dtoverlay -a | grep gpio-led ++ * ++ * # Load the overlay ++ * dtoverlay gpio-led label=moo gpio=19 ++ * ++ * # if nothing is shown, the overlay wasn't loaded successfully ++ * dtoverlay -l | grep gpio-led ++ * ++ * echo 1 > /sys/class/leds/moo/brightness ++ * echo 0 > /sys/class/leds/moo/brightness ++ * echo cpu > /sys/class/leds/moo/trigger ++ * echo heartbeat > /sys/class/leds/moo/trigger ++ * ++ * # unload the overlay ++ * dtoverlay -r gpio-led ++ * ++ * To load in /boot/config.txt add lines such as: ++ * dtoverlay=gpio-led,gpio=19,label=heart,trigger=heartbeat ++ * dtoverlay=gpio-led,gpio=26,label=brain,trigger=cpu ++ */ ++ ++/dts-v1/; ++/plugin/; ++ ++/ { ++ compatible = "brcm,bcm2835"; ++ ++ fragment@0 { ++ // Configure the gpio pin controller ++ target = <&gpio>; ++ __overlay__ { ++ led_pin: led_pins@19 { ++ brcm,pins = <19>; // gpio number ++ brcm,function = <1>; // 0 = input, 1 = output ++ brcm,pull = <0>; // 0 = none, 1 = pull down, 2 = pull up ++ }; ++ }; ++ }; ++ fragment@1 { ++ target-path = "/"; ++ __overlay__ { ++ leds: leds@0 { ++ compatible = "gpio-leds"; ++ pinctrl-names = "default"; ++ pinctrl-0 = <&led_pin>; ++ status = "okay"; ++ ++ led: led { ++ label = "myled1"; ++ gpios = <&gpio 19 0>; ++ linux,default-trigger = "none"; ++ }; ++ }; ++ }; ++ }; ++ ++ __overrides__ { ++ gpio = <&led>,"gpios:4", ++ <&leds>,"reg:0", ++ <&led_pin>,"brcm,pins:0", ++ <&led_pin>,"reg:0"; ++ label = <&led>,"label"; ++ active_low = <&led>,"gpios:8"; ++ trigger = <&led>,"linux,default-trigger"; ++ }; ++ ++}; ++ |