[PATCH] LED: add LED class
Richard Purdie [Fri, 31 Mar 2006 10:31:04 +0000 (02:31 -0800)]
Add the foundations of a new LEDs subsystem.  This patch adds a class which
presents LED devices within sysfs and allows their brightness to be
controlled.

Signed-off-by: Richard Purdie <rpurdie@rpsys.net>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

arch/arm/Kconfig
drivers/Kconfig
drivers/Makefile
drivers/leds/Kconfig [new file with mode: 0644]
drivers/leds/Makefile [new file with mode: 0644]
drivers/leds/led-class.c [new file with mode: 0644]
drivers/leds/led-core.c [new file with mode: 0644]
drivers/leds/leds.h [new file with mode: 0644]
include/linux/leds.h [new file with mode: 0644]

index ba46d77..e91db54 100644 (file)
@@ -839,6 +839,8 @@ source "drivers/misc/Kconfig"
 
 source "drivers/mfd/Kconfig"
 
+source "drivers/leds/Kconfig"
+
 source "drivers/media/Kconfig"
 
 source "drivers/video/Kconfig"
index 9f5c0da..5c91d6a 100644 (file)
@@ -64,6 +64,8 @@ source "drivers/usb/Kconfig"
 
 source "drivers/mmc/Kconfig"
 
+source "drivers/leds/Kconfig"
+
 source "drivers/infiniband/Kconfig"
 
 source "drivers/sn/Kconfig"
index 4249552..d6e8ffb 100644 (file)
@@ -69,6 +69,7 @@ obj-$(CONFIG_MCA)             += mca/
 obj-$(CONFIG_EISA)             += eisa/
 obj-$(CONFIG_CPU_FREQ)         += cpufreq/
 obj-$(CONFIG_MMC)              += mmc/
+obj-$(CONFIG_NEW_LEDS)         += leds/
 obj-$(CONFIG_INFINIBAND)       += infiniband/
 obj-$(CONFIG_SGI_SN)           += sn/
 obj-y                          += firmware/
diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
new file mode 100644 (file)
index 0000000..106f9ae
--- /dev/null
@@ -0,0 +1,18 @@
+
+menu "LED devices"
+
+config NEW_LEDS
+       bool "LED Support"
+       help
+         Say Y to enable Linux LED support.  This is not related to standard
+         keyboard LEDs which are controlled via the input system.
+
+config LEDS_CLASS
+       tristate "LED Class Support"
+       depends NEW_LEDS
+       help
+         This option enables the led sysfs class in /sys/class/leds.  You'll
+         need this to do anything useful with LEDs.  If unsure, say N.
+
+endmenu
+
diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile
new file mode 100644 (file)
index 0000000..8a62871
--- /dev/null
@@ -0,0 +1,4 @@
+
+# LED Core
+obj-$(CONFIG_NEW_LEDS)                 += led-core.o
+obj-$(CONFIG_LEDS_CLASS)               += led-class.o
diff --git a/drivers/leds/led-class.c b/drivers/leds/led-class.c
new file mode 100644 (file)
index 0000000..0292df4
--- /dev/null
@@ -0,0 +1,147 @@
+/*
+ * LED Class Core
+ *
+ * Copyright (C) 2005 John Lenz <lenz@cs.wisc.edu>
+ * Copyright (C) 2005-2006 Richard Purdie <rpurdie@openedhand.com>
+ *
+ * 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/config.h>
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/list.h>
+#include <linux/spinlock.h>
+#include <linux/device.h>
+#include <linux/sysdev.h>
+#include <linux/timer.h>
+#include <linux/err.h>
+#include <linux/leds.h>
+#include "leds.h"
+
+static struct class *leds_class;
+
+static ssize_t led_brightness_show(struct class_device *dev, char *buf)
+{
+       struct led_classdev *led_cdev = class_get_devdata(dev);
+       ssize_t ret = 0;
+
+       /* no lock needed for this */
+       sprintf(buf, "%u\n", led_cdev->brightness);
+       ret = strlen(buf) + 1;
+
+       return ret;
+}
+
+static ssize_t led_brightness_store(struct class_device *dev,
+                               const char *buf, size_t size)
+{
+       struct led_classdev *led_cdev = class_get_devdata(dev);
+       ssize_t ret = -EINVAL;
+       char *after;
+       unsigned long state = simple_strtoul(buf, &after, 10);
+
+       if (after - buf > 0) {
+               ret = after - buf;
+               led_set_brightness(led_cdev, state);
+       }
+
+       return ret;
+}
+
+static CLASS_DEVICE_ATTR(brightness, 0644, led_brightness_show,
+                       led_brightness_store);
+
+/**
+ * led_classdev_suspend - suspend an led_classdev.
+ * @led_cdev: the led_classdev to suspend.
+ */
+void led_classdev_suspend(struct led_classdev *led_cdev)
+{
+       led_cdev->flags |= LED_SUSPENDED;
+       led_cdev->brightness_set(led_cdev, 0);
+}
+EXPORT_SYMBOL_GPL(led_classdev_suspend);
+
+/**
+ * led_classdev_resume - resume an led_classdev.
+ * @led_cdev: the led_classdev to resume.
+ */
+void led_classdev_resume(struct led_classdev *led_cdev)
+{
+       led_cdev->brightness_set(led_cdev, led_cdev->brightness);
+       led_cdev->flags &= ~LED_SUSPENDED;
+}
+EXPORT_SYMBOL_GPL(led_classdev_resume);
+
+/**
+ * led_classdev_register - register a new object of led_classdev class.
+ * @dev: The device to register.
+ * @led_cdev: the led_classdev structure for this device.
+ */
+int led_classdev_register(struct device *parent, struct led_classdev *led_cdev)
+{
+       led_cdev->class_dev = class_device_create(leds_class, NULL, 0,
+                                               parent, "%s", led_cdev->name);
+       if (unlikely(IS_ERR(led_cdev->class_dev)))
+               return PTR_ERR(led_cdev->class_dev);
+
+       class_set_devdata(led_cdev->class_dev, led_cdev);
+
+       /* register the attributes */
+       class_device_create_file(led_cdev->class_dev,
+                               &class_device_attr_brightness);
+
+       /* add to the list of leds */
+       write_lock(&leds_list_lock);
+       list_add_tail(&led_cdev->node, &leds_list);
+       write_unlock(&leds_list_lock);
+
+       printk(KERN_INFO "Registered led device: %s\n",
+                       led_cdev->class_dev->class_id);
+
+       return 0;
+}
+EXPORT_SYMBOL_GPL(led_classdev_register);
+
+/**
+ * led_classdev_unregister - unregisters a object of led_properties class.
+ * @led_cdev: the led device to unreigister
+ *
+ * Unregisters a previously registered via led_classdev_register object.
+ */
+void led_classdev_unregister(struct led_classdev *led_cdev)
+{
+       class_device_remove_file(led_cdev->class_dev,
+                               &class_device_attr_brightness);
+
+       class_device_unregister(led_cdev->class_dev);
+
+       write_lock(&leds_list_lock);
+       list_del(&led_cdev->node);
+       write_unlock(&leds_list_lock);
+}
+EXPORT_SYMBOL_GPL(led_classdev_unregister);
+
+static int __init leds_init(void)
+{
+       leds_class = class_create(THIS_MODULE, "leds");
+       if (IS_ERR(leds_class))
+               return PTR_ERR(leds_class);
+       return 0;
+}
+
+static void __exit leds_exit(void)
+{
+       class_destroy(leds_class);
+}
+
+subsys_initcall(leds_init);
+module_exit(leds_exit);
+
+MODULE_AUTHOR("John Lenz, Richard Purdie");
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("LED Class Interface");
diff --git a/drivers/leds/led-core.c b/drivers/leds/led-core.c
new file mode 100644 (file)
index 0000000..fe65413
--- /dev/null
@@ -0,0 +1,25 @@
+/*
+ * LED Class Core
+ *
+ * Copyright 2005-2006 Openedhand Ltd.
+ *
+ * Author: Richard Purdie <rpurdie@openedhand.com>
+ *
+ * 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/kernel.h>
+#include <linux/list.h>
+#include <linux/module.h>
+#include <linux/spinlock.h>
+#include <linux/leds.h>
+#include "leds.h"
+
+rwlock_t leds_list_lock = RW_LOCK_UNLOCKED;
+LIST_HEAD(leds_list);
+
+EXPORT_SYMBOL_GPL(leds_list);
+EXPORT_SYMBOL_GPL(leds_list_lock);
diff --git a/drivers/leds/leds.h b/drivers/leds/leds.h
new file mode 100644 (file)
index 0000000..d26ca2f
--- /dev/null
@@ -0,0 +1,31 @@
+/*
+ * LED Core
+ *
+ * Copyright 2005 Openedhand Ltd.
+ *
+ * Author: Richard Purdie <rpurdie@openedhand.com>
+ *
+ * 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.
+ *
+ */
+#ifndef __LEDS_H_INCLUDED
+#define __LEDS_H_INCLUDED
+
+#include <linux/leds.h>
+
+static inline void led_set_brightness(struct led_classdev *led_cdev,
+                                       enum led_brightness value)
+{
+       if (value > LED_FULL)
+               value = LED_FULL;
+       led_cdev->brightness = value;
+       if (!(led_cdev->flags & LED_SUSPENDED))
+               led_cdev->brightness_set(led_cdev, value);
+}
+
+extern rwlock_t leds_list_lock;
+extern struct list_head leds_list;
+
+#endif /* __LEDS_H_INCLUDED */
diff --git a/include/linux/leds.h b/include/linux/leds.h
new file mode 100644 (file)
index 0000000..6812640
--- /dev/null
@@ -0,0 +1,51 @@
+/*
+ * Driver model for leds and led triggers
+ *
+ * Copyright (C) 2005 John Lenz <lenz@cs.wisc.edu>
+ * Copyright (C) 2005 Richard Purdie <rpurdie@openedhand.com>
+ *
+ * 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.
+ *
+ */
+#ifndef __LINUX_LEDS_H_INCLUDED
+#define __LINUX_LEDS_H_INCLUDED
+
+struct device;
+struct class_device;
+/*
+ * LED Core
+ */
+
+enum led_brightness {
+       LED_OFF = 0,
+       LED_HALF = 127,
+       LED_FULL = 255,
+};
+
+struct led_classdev {
+       const char *name;
+       int brightness;
+       int flags;
+#define LED_SUSPENDED       (1 << 0)
+
+       /* A function to set the brightness of the led */
+       void (*brightness_set)(struct led_classdev *led_cdev,
+                               enum led_brightness brightness);
+
+       struct class_device *class_dev;
+       /* LED Device linked list */
+       struct list_head node;
+
+       /* Trigger data */
+       char *default_trigger;
+};
+
+extern int led_classdev_register(struct device *parent,
+                               struct led_classdev *led_cdev);
+extern void led_classdev_unregister(struct led_classdev *led_cdev);
+extern void led_classdev_suspend(struct led_classdev *led_cdev);
+extern void led_classdev_resume(struct led_classdev *led_cdev);
+
+#endif         /* __LINUX_LEDS_H_INCLUDED */