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-rw-r--r--drivers/leds/Kconfig8
-rw-r--r--drivers/leds/Makefile3
-rw-r--r--drivers/leds/uleds.c235
3 files changed, 246 insertions, 0 deletions
diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
index 7a628c6516f6..5fd3f4ca0c3c 100644
--- a/drivers/leds/Kconfig
+++ b/drivers/leds/Kconfig
@@ -659,6 +659,14 @@ config LEDS_MLXCPLD
This option enabled support for the LEDs on the Mellanox
boards. Say Y to enabled these.
+config LEDS_USER
+ tristate "Userspace LED support"
+ depends on LEDS_CLASS
+ help
+ This option enables support for userspace LEDs. Say 'y' to enable this
+ support in kernel. To compile this driver as a module, choose 'm' here:
+ the module will be called uleds.
+
comment "LED Triggers"
source "drivers/leds/trigger/Kconfig"
diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile
index 3965070190f5..d5331ff5b563 100644
--- a/drivers/leds/Makefile
+++ b/drivers/leds/Makefile
@@ -75,5 +75,8 @@ obj-$(CONFIG_LEDS_MLXCPLD) += leds-mlxcpld.o
# LED SPI Drivers
obj-$(CONFIG_LEDS_DAC124S085) += leds-dac124s085.o
+# LED Userspace Drivers
+obj-$(CONFIG_LEDS_USER) += uleds.o
+
# LED Triggers
obj-$(CONFIG_LEDS_TRIGGERS) += trigger/
diff --git a/drivers/leds/uleds.c b/drivers/leds/uleds.c
new file mode 100644
index 000000000000..5e9e8a1fdefb
--- /dev/null
+++ b/drivers/leds/uleds.c
@@ -0,0 +1,235 @@
+/*
+ * Userspace driver for the LED subsystem
+ *
+ * Copyright (C) 2016 David Lechner <david@lechnology.com>
+ *
+ * Based on uinput.c: Aristeu Sergio Rozanski Filho <aris@cathedrallabs.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+#include <linux/fs.h>
+#include <linux/init.h>
+#include <linux/leds.h>
+#include <linux/miscdevice.h>
+#include <linux/module.h>
+#include <linux/poll.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+
+#include <uapi/linux/uleds.h>
+
+#define ULEDS_NAME "uleds"
+
+enum uleds_state {
+ ULEDS_STATE_UNKNOWN,
+ ULEDS_STATE_REGISTERED,
+};
+
+struct uleds_device {
+ struct uleds_user_dev user_dev;
+ struct led_classdev led_cdev;
+ struct mutex mutex;
+ enum uleds_state state;
+ wait_queue_head_t waitq;
+ int brightness;
+ bool new_data;
+};
+
+static struct miscdevice uleds_misc;
+
+static void uleds_brightness_set(struct led_classdev *led_cdev,
+ enum led_brightness brightness)
+{
+ struct uleds_device *udev = container_of(led_cdev, struct uleds_device,
+ led_cdev);
+
+ if (udev->brightness != brightness) {
+ udev->brightness = brightness;
+ udev->new_data = true;
+ wake_up_interruptible(&udev->waitq);
+ }
+}
+
+static int uleds_open(struct inode *inode, struct file *file)
+{
+ struct uleds_device *udev;
+
+ udev = kzalloc(sizeof(*udev), GFP_KERNEL);
+ if (!udev)
+ return -ENOMEM;
+
+ udev->led_cdev.name = udev->user_dev.name;
+ udev->led_cdev.brightness_set = uleds_brightness_set;
+
+ mutex_init(&udev->mutex);
+ init_waitqueue_head(&udev->waitq);
+ udev->state = ULEDS_STATE_UNKNOWN;
+
+ file->private_data = udev;
+ nonseekable_open(inode, file);
+
+ return 0;
+}
+
+static ssize_t uleds_write(struct file *file, const char __user *buffer,
+ size_t count, loff_t *ppos)
+{
+ struct uleds_device *udev = file->private_data;
+ const char *name;
+ int ret;
+
+ if (count == 0)
+ return 0;
+
+ ret = mutex_lock_interruptible(&udev->mutex);
+ if (ret)
+ return ret;
+
+ if (udev->state == ULEDS_STATE_REGISTERED) {
+ ret = -EBUSY;
+ goto out;
+ }
+
+ if (count != sizeof(struct uleds_user_dev)) {
+ ret = -EINVAL;
+ goto out;
+ }
+
+ if (copy_from_user(&udev->user_dev, buffer,
+ sizeof(struct uleds_user_dev))) {
+ ret = -EFAULT;
+ goto out;
+ }
+
+ name = udev->user_dev.name;
+ if (!name[0] || !strcmp(name, ".") || !strcmp(name, "..") ||
+ strchr(name, '/')) {
+ ret = -EINVAL;
+ goto out;
+ }
+
+ if (udev->user_dev.max_brightness <= 0) {
+ ret = -EINVAL;
+ goto out;
+ }
+ udev->led_cdev.max_brightness = udev->user_dev.max_brightness;
+
+ ret = devm_led_classdev_register(uleds_misc.this_device,
+ &udev->led_cdev);
+ if (ret < 0)
+ goto out;
+
+ udev->new_data = true;
+ udev->state = ULEDS_STATE_REGISTERED;
+ ret = count;
+
+out:
+ mutex_unlock(&udev->mutex);
+
+ return ret;
+}
+
+static ssize_t uleds_read(struct file *file, char __user *buffer, size_t count,
+ loff_t *ppos)
+{
+ struct uleds_device *udev = file->private_data;
+ ssize_t retval;
+
+ if (count < sizeof(udev->brightness))
+ return 0;
+
+ do {
+ retval = mutex_lock_interruptible(&udev->mutex);
+ if (retval)
+ return retval;
+
+ if (udev->state != ULEDS_STATE_REGISTERED) {
+ retval = -ENODEV;
+ } else if (!udev->new_data && (file->f_flags & O_NONBLOCK)) {
+ retval = -EAGAIN;
+ } else if (udev->new_data) {
+ retval = copy_to_user(buffer, &udev->brightness,
+ sizeof(udev->brightness));
+ udev->new_data = false;
+ retval = sizeof(udev->brightness);
+ }
+
+ mutex_unlock(&udev->mutex);
+
+ if (retval)
+ break;
+
+ if (!(file->f_flags & O_NONBLOCK))
+ retval = wait_event_interruptible(udev->waitq,
+ udev->new_data ||
+ udev->state != ULEDS_STATE_REGISTERED);
+ } while (retval == 0);
+
+ return retval;
+}
+
+static unsigned int uleds_poll(struct file *file, poll_table *wait)
+{
+ struct uleds_device *udev = file->private_data;
+
+ poll_wait(file, &udev->waitq, wait);
+
+ if (udev->new_data)
+ return POLLIN | POLLRDNORM;
+
+ return 0;
+}
+
+static int uleds_release(struct inode *inode, struct file *file)
+{
+ struct uleds_device *udev = file->private_data;
+
+ if (udev->state == ULEDS_STATE_REGISTERED) {
+ udev->state = ULEDS_STATE_UNKNOWN;
+ devm_led_classdev_unregister(uleds_misc.this_device,
+ &udev->led_cdev);
+ }
+ kfree(udev);
+
+ return 0;
+}
+
+static const struct file_operations uleds_fops = {
+ .owner = THIS_MODULE,
+ .open = uleds_open,
+ .release = uleds_release,
+ .read = uleds_read,
+ .write = uleds_write,
+ .poll = uleds_poll,
+ .llseek = no_llseek,
+};
+
+static struct miscdevice uleds_misc = {
+ .fops = &uleds_fops,
+ .minor = MISC_DYNAMIC_MINOR,
+ .name = ULEDS_NAME,
+};
+
+static int __init uleds_init(void)
+{
+ return misc_register(&uleds_misc);
+}
+module_init(uleds_init);
+
+static void __exit uleds_exit(void)
+{
+ misc_deregister(&uleds_misc);
+}
+module_exit(uleds_exit);
+
+MODULE_AUTHOR("David Lechner <david@lechnology.com>");
+MODULE_DESCRIPTION("Userspace driver for the LED subsystem");
+MODULE_LICENSE("GPL");
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-21 12:46:24 +0000