Attempting to consolidate the ARM LED code, this removes the custom RealView LED trigger code to turn LEDs on and off in response to CPU activity and replace it with a standard trigger. (bryan.wu@xxxxxxxxxxxxx: It introduces several syscore stubs into this trigger. It also provides ledtrig_cpu trigger event stub in <linux/leds.h>. Although it was inspired by ARM work, it can be used in other arch.) Cc: Richard Purdie <rpurdie@xxxxxxxxx> Signed-off-by: Linus Walleij <linus.walleij@xxxxxxxxxx> Signed-off-by: Bryan Wu <bryan.wu@xxxxxxxxxxxxx> Reviewed-by: Jamie Iles <jamie@xxxxxxxxxxxxx> Tested-by: Jochen Friedrich <jochen@xxxxxxxx> --- drivers/leds/Kconfig | 10 +++ drivers/leds/Makefile | 1 + drivers/leds/ledtrig-cpu.c | 150 ++++++++++++++++++++++++++++++++++++++++++++ include/linux/leds.h | 16 +++++ 4 files changed, 177 insertions(+) create mode 100644 drivers/leds/ledtrig-cpu.c diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig index 5f12659..dbf8a4c 100644 --- a/drivers/leds/Kconfig +++ b/drivers/leds/Kconfig @@ -465,6 +465,16 @@ config LEDS_TRIGGER_BACKLIGHT If unsure, say N. +config LEDS_TRIGGER_CPU + tristate "LED CPU Trigger" + depends on LEDS_TRIGGERS + help + This allows LEDs to be controlled by active CPUs. This shows + the active CPUs across an array of LEDs so you can see which + CPUs are active on the system at any given moment. + + If unsure, say N. + config LEDS_TRIGGER_GPIO tristate "LED GPIO Trigger" depends on LEDS_TRIGGERS diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile index 9475bbb..ea1efb2 100644 --- a/drivers/leds/Makefile +++ b/drivers/leds/Makefile @@ -56,4 +56,5 @@ obj-$(CONFIG_LEDS_TRIGGER_IDE_DISK) += ledtrig-ide-disk.o obj-$(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_DEFAULT_ON) += ledtrig-default-on.o diff --git a/drivers/leds/ledtrig-cpu.c b/drivers/leds/ledtrig-cpu.c new file mode 100644 index 0000000..1f752e1 --- /dev/null +++ b/drivers/leds/ledtrig-cpu.c @@ -0,0 +1,150 @@ +/* + * ledtrig-cpu.c - LED trigger based on CPU activity + * + * This LED trigger will be registered for each possible CPU and named as + * cpu0, cpu1, cpu2, cpu3, etc. + * + * It can be bound to any LED just like other triggers using either a + * board file or via sysfs interface. + * + * An API named ledtrig_cpu is exported for any user, who want to add CPU + * activity indication in their code + * + * Copyright 2011 Linus Walleij <linus.walleij@xxxxxxxxxx> + * Copyright 2011 - 2012 Bryan Wu <bryan.wu@xxxxxxxxxxxxx> + * + * 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/module.h> +#include <linux/kernel.h> +#include <linux/init.h> +#include <linux/slab.h> +#include <linux/percpu.h> +#include <linux/syscore_ops.h> +#include <linux/rwsem.h> +#include "leds.h" + +#define MAX_NAME_LEN 8 + +static DEFINE_PER_CPU(struct led_trigger *, cpu_trig); +static DEFINE_PER_CPU(char [MAX_NAME_LEN], trig_name); +static DEFINE_PER_CPU(struct rw_semaphore, trig_lock); + +/** + * ledtrig_cpu - emit a CPU event as a trigger + * @evt: CPU event to be emitted + * + * Emit a CPU event on a CPU core, which will trigger a + * binded LED to turn on or turn off. + */ +void ledtrig_cpu(enum cpu_led_event ledevt) +{ + struct led_trigger *trig = __get_cpu_var(cpu_trig); + + if (!trig) + return; + + /* Locate the correct CPU LED */ + switch (ledevt) { + case CPU_LED_IDLE_END: + case CPU_LED_START: + /* Will turn the LED on, max brightness */ + led_trigger_event(trig, LED_FULL); + break; + + case CPU_LED_IDLE_START: + case CPU_LED_STOP: + case CPU_LED_HALTED: + /* Will turn the LED off */ + led_trigger_event(trig, LED_OFF); + break; + + default: + /* Will leave the LED as it is */ + break; + } +} +EXPORT_SYMBOL(ledtrig_cpu); + +static int ledtrig_cpu_syscore_suspend(void) +{ + ledtrig_cpu(CPU_LED_STOP); + return 0; +} + +static void ledtrig_cpu_syscore_resume(void) +{ + ledtrig_cpu(CPU_LED_START); +} + +static void ledtrig_cpu_syscore_shutdown(void) +{ + ledtrig_cpu(CPU_LED_HALTED); +} + +static struct syscore_ops ledtrig_cpu_syscore_ops = { + .shutdown = ledtrig_cpu_syscore_shutdown, + .suspend = ledtrig_cpu_syscore_suspend, + .resume = ledtrig_cpu_syscore_resume, +}; + +static int __init ledtrig_cpu_init(void) +{ + int cpu; + + /* Supports up to 9999 cpu cores */ + BUILD_BUG_ON(CONFIG_NR_CPUS > 9999); + + /* + * Registering CPU led trigger for each CPU core here + * ignores CPU hotplug, but after this CPU hotplug works + * fine with this trigger. + */ + for_each_possible_cpu(cpu) { + struct led_trigger *trig; + char *name = per_cpu(trig_name, cpu); + struct rw_semaphore *lock = &per_cpu(trig_lock, cpu); + + init_rwsem(lock); + + snprintf(name, MAX_NAME_LEN, "cpu%d", cpu); + + down_write(lock); + led_trigger_register_simple(name, &trig); + per_cpu(cpu_trig, cpu) = trig; + up_write(lock); + } + + register_syscore_ops(&ledtrig_cpu_syscore_ops); + + pr_info("ledtrig-cpu: registered to indicate activity on CPUs\n"); + + return 0; +} +module_init(ledtrig_cpu_init); + +static void __exit ledtrig_cpu_exit(void) +{ + int cpu; + + for_each_possible_cpu(cpu) { + struct led_trigger *trig = per_cpu(cpu_trig, cpu); + char *name = per_cpu(trig_name, cpu); + + led_trigger_unregister_simple(trig); + per_cpu(cpu_trig, cpu) = NULL; + memset(name, 0, MAX_NAME_LEN); + } + + unregister_syscore_ops(&ledtrig_cpu_syscore_ops); +} +module_exit(ledtrig_cpu_exit); + +MODULE_AUTHOR("Linus Walleij <linus.walleij@xxxxxxxxxx>"); +MODULE_AUTHOR("Bryan Wu <bryan.wu@xxxxxxxxxxxxx>"); +MODULE_DESCRIPTION("CPU LED trigger"); +MODULE_LICENSE("GPL"); diff --git a/include/linux/leds.h b/include/linux/leds.h index 39eee41..aaf88b0 100644 --- a/include/linux/leds.h +++ b/include/linux/leds.h @@ -212,4 +212,20 @@ struct gpio_led_platform_data { struct platform_device *gpio_led_register_device( int id, const struct gpio_led_platform_data *pdata); +enum cpu_led_event { + CPU_LED_IDLE_START, /* CPU enters idle */ + CPU_LED_IDLE_END, /* CPU idle ends */ + CPU_LED_START, /* Machine starts, especially resume */ + CPU_LED_STOP, /* Machine stops, especially suspend */ + CPU_LED_HALTED, /* Machine shutdown */ +}; +#if defined(CONFIG_LEDS_TRIGGER_CPU) || defined(CONFIG_LEDS_TRIGGER_CPU_MODULE) +extern void ledtrig_cpu(enum cpu_led_event evt); +#else +static inline void ledtrig_cpu(enum cpu_led_event evt) +{ + return; +} +#endif + #endif /* __LINUX_LEDS_H_INCLUDED */ -- 1.7.9.5 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@xxxxxxxxxxxxxxxxxxx http://lists.infradead.org/mailman/listinfo/linux-arm-kernel