[PATCH 2/11] LED: Add LED Class

[Richard Purdie <rpurdie@rpsys.net>]

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>

Index: linux-2.6.15/drivers/leds/Kconfig
===================================================================
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ linux-2.6.15/drivers/leds/Kconfig	2006-01-29 16:02:38.000000000 +0000
@@ -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
+
Index: linux-2.6.15/drivers/leds/Makefile
===================================================================
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ linux-2.6.15/drivers/leds/Makefile	2006-01-29 16:02:38.000000000 +0000
@@ -0,0 +1,4 @@
+
+# LED Core
+obj-$(CONFIG_NEW_LEDS)			+= led-core.o
+obj-$(CONFIG_LEDS_CLASS)		+= led-class.o
Index: linux-2.6.15/include/linux/leds.h
===================================================================
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ linux-2.6.15/include/linux/leds.h	2006-01-29 16:03:21.000000000 +0000
@@ -0,0 +1,48 @@
+/*
+ * 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.
+ *
+ */
+
+struct device;
+struct class_device;
+/*
+ * LED Core
+ */
+
+enum led_brightness {
+	LED_OFF = 0,
+	LED_HALF = 127,
+	LED_FULL = 255,
+};
+
+struct led_device {
+	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_device *led_dev, enum led_brightness brightness);
+
+	struct class_device *class_dev;
+	/* LED Device linked list */
+	struct list_head node;
+
+	/* Trigger data */
+	char *default_trigger;
+
+	/* This protects the data in this structure */
+	rwlock_t lock;
+};
+
+extern int led_device_register(struct device *dev, struct led_device *led_dev);
+extern void led_device_unregister(struct led_device *led_dev);
+extern void led_device_suspend(struct led_device *led_dev);
+extern void led_device_resume(struct led_device *led_dev);
Index: linux-2.6.15/arch/arm/Kconfig
===================================================================
--- linux-2.6.15.orig/arch/arm/Kconfig	2006-01-29 14:37:31.000000000 +0000
+++ linux-2.6.15/arch/arm/Kconfig	2006-01-29 16:02:15.000000000 +0000
@@ -774,6 +774,8 @@
 
 source "drivers/mfd/Kconfig"
 
+source "drivers/leds/Kconfig"
+
 source "drivers/media/Kconfig"
 
 source "drivers/video/Kconfig"
Index: linux-2.6.15/drivers/Makefile
===================================================================
--- linux-2.6.15.orig/drivers/Makefile	2006-01-29 14:42:52.000000000 +0000
+++ linux-2.6.15/drivers/Makefile	2006-01-29 14:43:11.000000000 +0000
@@ -68,6 +68,7 @@
 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_IOC4)		+= sn/
 obj-y				+= firmware/
Index: linux-2.6.15/drivers/Kconfig
===================================================================
--- linux-2.6.15.orig/drivers/Kconfig	2006-01-29 14:42:51.000000000 +0000
+++ linux-2.6.15/drivers/Kconfig	2006-01-29 14:43:11.000000000 +0000
@@ -64,6 +64,8 @@
 
 source "drivers/mmc/Kconfig"
 
+source "drivers/leds/Kconfig"
+
 source "drivers/infiniband/Kconfig"
 
 source "drivers/sn/Kconfig"
Index: linux-2.6.15/drivers/leds/leds.h
===================================================================
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ linux-2.6.15/drivers/leds/leds.h	2006-01-29 16:02:38.000000000 +0000
@@ -0,0 +1,26 @@
+/*
+ * 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.
+ *
+ */
+
+/* led_dev->lock must be held as write */
+static inline void led_set_brightness(struct led_device *led_dev, enum led_brightness value)
+{
+	if (value > LED_FULL)
+		value = LED_FULL;
+	led_dev->brightness = value;
+	if (!(led_dev->flags & LED_SUSPENDED))
+		led_dev->brightness_set(led_dev, value);
+}
+
+extern rwlock_t leds_list_lock;
+extern struct list_head leds_list;
+
Index: linux-2.6.15/drivers/leds/led-class.c
===================================================================
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ linux-2.6.15/drivers/leds/led-class.c	2006-01-29 16:02:38.000000000 +0000
@@ -0,0 +1,150 @@
+/*
+ * 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_device *led_dev = dev->class_data;
+	ssize_t ret = 0;
+
+	/* no lock needed for this */
+	sprintf(buf, "%u\n", led_dev->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_device *led_dev = dev->class_data;
+	ssize_t ret = -EINVAL;
+	char *after;
+
+	unsigned long state = simple_strtoul(buf, &after, 10);
+	if (after - buf > 0) {
+		ret = after - buf;
+		write_lock(&led_dev->lock);
+		led_set_brightness(led_dev, state);
+		write_unlock(&led_dev->lock);
+	}
+
+	return ret;
+}
+
+static CLASS_DEVICE_ATTR(brightness, 0644, led_brightness_show, led_brightness_store);
+
+
+/**
+ * led_device_suspend - suspend an led_device.
+ * @led_dev: the led_device to suspend.
+ */
+void led_device_suspend(struct led_device *led_dev)
+{
+	write_lock(&led_dev->lock);
+	led_dev->flags |= LED_SUSPENDED;
+	led_dev->brightness_set(led_dev, 0);
+	write_unlock(&led_dev->lock);
+}
+
+/**
+ * led_device_resume - resume an led_device.
+ * @led_dev: the led_device to resume.
+ */
+void led_device_resume(struct led_device *led_dev)
+{
+	write_lock(&led_dev->lock);
+	led_dev->flags &= ~LED_SUSPENDED;
+	led_dev->brightness_set(led_dev, led_dev->brightness);
+	write_unlock(&led_dev->lock);
+}
+
+/**
+ * led_device_register - register a new object of led_device class.
+ * @dev: The device to register.
+ * @led_dev: the led_device structure for this device.
+ */
+int led_device_register(struct device *dev, struct led_device *led_dev)
+{
+	led_dev->class_dev = class_device_create(leds_class, NULL, 0, dev, "%s", led_dev->name);
+	if (unlikely(IS_ERR(led_dev->class_dev)))
+		return PTR_ERR(led_dev->class_dev);
+
+	rwlock_init(&led_dev->lock);
+	led_dev->class_dev->class_data = led_dev;
+
+	/* register the attributes */
+	class_device_create_file(led_dev->class_dev, &class_device_attr_brightness);
+
+	/* add to the list of leds */
+	write_lock(&leds_list_lock);
+	list_add_tail(&led_dev->node, &leds_list);
+	write_unlock(&leds_list_lock);
+
+	printk(KERN_INFO "Registered led device: %s\n", led_dev->class_dev->class_id);
+
+	return 0;
+}
+
+/**
+ * led_device_unregister - unregisters a object of led_properties class.
+ * @led_dev: the led device to unreigister
+ *
+ * Unregisters a previously registered via led_device_register object.
+ */
+void led_device_unregister(struct led_device *led_dev)
+{
+	class_device_remove_file(led_dev->class_dev, &class_device_attr_brightness);
+
+	class_device_unregister(led_dev->class_dev);
+
+	write_lock(&leds_list_lock);
+	list_del(&led_dev->node);
+	write_unlock(&leds_list_lock);
+}
+
+EXPORT_SYMBOL_GPL(led_device_suspend);
+EXPORT_SYMBOL_GPL(led_device_resume);
+EXPORT_SYMBOL_GPL(led_device_register);
+EXPORT_SYMBOL_GPL(led_device_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");
Index: linux-2.6.15/drivers/leds/led-core.c
===================================================================
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ linux-2.6.15/drivers/leds/led-core.c	2006-01-29 14:43:11.000000000 +0000
@@ -0,0 +1,24 @@
+/*
+ * 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);