From 44e1e9f8e70506728b02a18e6d03599a6485d67f Mon Sep 17 00:00:00 2001 From: Shuah Khan Date: Tue, 29 May 2012 15:07:30 -0700 Subject: leds: add new transient trigger for one shot timer activation The leds timer trigger does not currently have an interface to activate a one shot timer. The current support allows for setting two timers, one for specifying how long a state to be on, and the second for how long the state to be off. The delay_on value specifies the time period an LED should stay in on state, followed by a delay_off value that specifies how long the LED should stay in off state. The on and off cycle repeats until the trigger gets deactivated. There is no provision for one time activation to implement features that require an on or off state to be held just once and then stay in the original state forever. Without one shot timer interface, user space can still use timer trigger to set a timer to hold a state, however when user space application crashes or goes away without deactivating the timer, the hardware will be left in that state permanently. As a specific example of this use-case, let's look at vibrate feature on phones. Vibrate function on phones is implemented using PWM pins on SoC or PMIC. There is a need to activate one shot timer to control the vibrate feature, to prevent user space crashes leaving the phone in vibrate mode permanently causing the battery to drain. This trigger exports three properties, activate, state, and duration When transient trigger is activated these properties are set to default values. - duration allows setting timer value in msecs. The initial value is 0. - activate allows activating and deactivating the timer specified by duration as needed. The initial and default value is 0. This will allow duration to be set after trigger activation. - state allows user to specify a transient state to be held for the specified duration. Signed-off-by: Shuah Khan Cc: Jonas Bonn Cc: Richard Purdie Cc: NeilBrown Cc: Bryan Wu Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/leds/Kconfig | 8 ++ drivers/leds/Makefile | 1 + drivers/leds/ledtrig-transient.c | 237 +++++++++++++++++++++++++++++++++++++++ 3 files changed, 246 insertions(+) create mode 100644 drivers/leds/ledtrig-transient.c (limited to 'drivers/leds') diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig index cede3397bb1..6b2e1e4fdeb 100644 --- a/drivers/leds/Kconfig +++ b/drivers/leds/Kconfig @@ -479,4 +479,12 @@ config LEDS_TRIGGER_DEFAULT_ON comment "iptables trigger is under Netfilter config (LED target)" depends on LEDS_TRIGGERS +config LEDS_TRIGGER_TRANSIENT + tristate "LED Transient Trigger" + depends on LEDS_TRIGGERS + help + This allows one time activation of a transient state on + GPIO/PWM based hadrware. + If unsure, say Y. + endif # NEW_LEDS diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile index 900f9294bd8..4a4b96e8c3e 100644 --- a/drivers/leds/Makefile +++ b/drivers/leds/Makefile @@ -57,3 +57,4 @@ 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_DEFAULT_ON) += ledtrig-default-on.o +obj-$(CONFIG_LEDS_TRIGGER_TRANSIENT) += ledtrig-transient.o diff --git a/drivers/leds/ledtrig-transient.c b/drivers/leds/ledtrig-transient.c new file mode 100644 index 00000000000..83179f435e1 --- /dev/null +++ b/drivers/leds/ledtrig-transient.c @@ -0,0 +1,237 @@ +/* + * LED Kernel Transient Trigger + * + * Copyright (C) 2012 Shuah Khan + * + * Based on Richard Purdie's ledtrig-timer.c and Atsushi Nemoto's + * ledtrig-heartbeat.c + * Design and use-case input from Jonas Bonn and + * Neil Brown + * + * 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. + * + */ +/* + * Transient trigger allows one shot timer activation. Please refer to + * Documentation/leds/ledtrig-transient.txt for details +*/ + +#include +#include +#include +#include +#include +#include +#include +#include "leds.h" + +struct transient_trig_data { + int activate; + int state; + int restore_state; + unsigned long duration; + struct timer_list timer; +}; + +static void transient_timer_function(unsigned long data) +{ + struct led_classdev *led_cdev = (struct led_classdev *) data; + struct transient_trig_data *transient_data = led_cdev->trigger_data; + + transient_data->activate = 0; + led_set_brightness(led_cdev, transient_data->restore_state); +} + +static ssize_t transient_activate_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct led_classdev *led_cdev = dev_get_drvdata(dev); + struct transient_trig_data *transient_data = led_cdev->trigger_data; + + return sprintf(buf, "%d\n", transient_data->activate); +} + +static ssize_t transient_activate_store(struct device *dev, + struct device_attribute *attr, const char *buf, size_t size) +{ + struct led_classdev *led_cdev = dev_get_drvdata(dev); + struct transient_trig_data *transient_data = led_cdev->trigger_data; + unsigned long state; + ssize_t ret; + + ret = kstrtoul(buf, 10, &state); + if (ret) + return ret; + + if (state != 1 && state != 0) + return -EINVAL; + + /* cancel the running timer */ + if (state == 0 && transient_data->activate == 1) { + del_timer(&transient_data->timer); + transient_data->activate = state; + led_set_brightness(led_cdev, transient_data->restore_state); + return size; + } + + /* start timer if there is no active timer */ + if (state == 1 && transient_data->activate == 0 && + transient_data->duration != 0) { + transient_data->activate = state; + led_set_brightness(led_cdev, transient_data->state); + transient_data->restore_state = + (transient_data->state == LED_FULL) ? LED_OFF : LED_FULL; + mod_timer(&transient_data->timer, + jiffies + transient_data->duration); + } + + /* state == 0 && transient_data->activate == 0 + timer is not active - just return */ + /* state == 1 && transient_data->activate == 1 + timer is already active - just return */ + + return size; +} + +static ssize_t transient_duration_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct led_classdev *led_cdev = dev_get_drvdata(dev); + struct transient_trig_data *transient_data = led_cdev->trigger_data; + + return sprintf(buf, "%lu\n", transient_data->duration); +} + +static ssize_t transient_duration_store(struct device *dev, + struct device_attribute *attr, const char *buf, size_t size) +{ + struct led_classdev *led_cdev = dev_get_drvdata(dev); + struct transient_trig_data *transient_data = led_cdev->trigger_data; + unsigned long state; + ssize_t ret; + + ret = kstrtoul(buf, 10, &state); + if (ret) + return ret; + + transient_data->duration = state; + return size; +} + +static ssize_t transient_state_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct led_classdev *led_cdev = dev_get_drvdata(dev); + struct transient_trig_data *transient_data = led_cdev->trigger_data; + int state; + + state = (transient_data->state == LED_FULL) ? 1 : 0; + return sprintf(buf, "%d\n", state); +} + +static ssize_t transient_state_store(struct device *dev, + struct device_attribute *attr, const char *buf, size_t size) +{ + struct led_classdev *led_cdev = dev_get_drvdata(dev); + struct transient_trig_data *transient_data = led_cdev->trigger_data; + unsigned long state; + ssize_t ret; + + ret = kstrtoul(buf, 10, &state); + if (ret) + return ret; + + if (state != 1 && state != 0) + return -EINVAL; + + transient_data->state = (state == 1) ? LED_FULL : LED_OFF; + return size; +} + +static DEVICE_ATTR(activate, 0644, transient_activate_show, + transient_activate_store); +static DEVICE_ATTR(duration, 0644, transient_duration_show, + transient_duration_store); +static DEVICE_ATTR(state, 0644, transient_state_show, transient_state_store); + +static void transient_trig_activate(struct led_classdev *led_cdev) +{ + int rc; + struct transient_trig_data *tdata; + + tdata = kzalloc(sizeof(struct transient_trig_data), GFP_KERNEL); + if (!tdata) { + dev_err(led_cdev->dev, + "unable to allocate transient trigger\n"); + return; + } + led_cdev->trigger_data = tdata; + + rc = device_create_file(led_cdev->dev, &dev_attr_activate); + if (rc) + goto err_out; + + rc = device_create_file(led_cdev->dev, &dev_attr_duration); + if (rc) + goto err_out_duration; + + rc = device_create_file(led_cdev->dev, &dev_attr_state); + if (rc) + goto err_out_state; + + setup_timer(&tdata->timer, transient_timer_function, + (unsigned long) led_cdev); + led_cdev->activated = true; + + return; + +err_out_state: + device_remove_file(led_cdev->dev, &dev_attr_duration); +err_out_duration: + device_remove_file(led_cdev->dev, &dev_attr_activate); +err_out: + dev_err(led_cdev->dev, "unable to register transient trigger\n"); + led_cdev->trigger_data = NULL; + kfree(tdata); +} + +static void transient_trig_deactivate(struct led_classdev *led_cdev) +{ + struct transient_trig_data *transient_data = led_cdev->trigger_data; + + if (led_cdev->activated) { + del_timer_sync(&transient_data->timer); + led_set_brightness(led_cdev, transient_data->restore_state); + device_remove_file(led_cdev->dev, &dev_attr_activate); + device_remove_file(led_cdev->dev, &dev_attr_duration); + device_remove_file(led_cdev->dev, &dev_attr_state); + led_cdev->trigger_data = NULL; + led_cdev->activated = false; + kfree(transient_data); + } +} + +static struct led_trigger transient_trigger = { + .name = "transient", + .activate = transient_trig_activate, + .deactivate = transient_trig_deactivate, +}; + +static int __init transient_trig_init(void) +{ + return led_trigger_register(&transient_trigger); +} + +static void __exit transient_trig_exit(void) +{ + led_trigger_unregister(&transient_trigger); +} + +module_init(transient_trig_init); +module_exit(transient_trig_exit); + +MODULE_AUTHOR("Shuah Khan "); +MODULE_DESCRIPTION("Transient LED trigger"); +MODULE_LICENSE("GPL"); -- cgit v1.2.3