Input: add skeleton for simple polled devices
input-polldev provides a skeleton for supporting simple input
devices that need to be periodically scanned or polled to
detect changes in their state.
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
diff --git a/drivers/input/misc/input-polldev.c b/drivers/input/misc/input-polldev.c
new file mode 100644
index 0000000..1b2b9c9
--- /dev/null
+++ b/drivers/input/misc/input-polldev.c
@@ -0,0 +1,171 @@
+/*
+ * Generic implementation of a polled input device
+
+ * Copyright (c) 2007 Dmitry Torokhov
+ *
+ * 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/jiffies.h>
+#include <linux/mutex.h>
+#include <linux/input-polldev.h>
+
+static DEFINE_MUTEX(polldev_mutex);
+static int polldev_users;
+static struct workqueue_struct *polldev_wq;
+
+static int input_polldev_start_workqueue(void)
+{
+ int retval;
+
+ retval = mutex_lock_interruptible(&polldev_mutex);
+ if (retval)
+ return retval;
+
+ if (!polldev_users) {
+ polldev_wq = create_singlethread_workqueue("ipolldevd");
+ if (!polldev_wq) {
+ printk(KERN_ERR "input-polldev: failed to create "
+ "ipolldevd workqueue\n");
+ retval = -ENOMEM;
+ goto out;
+ }
+ }
+
+ polldev_users++;
+
+ out:
+ mutex_unlock(&polldev_mutex);
+ return retval;
+}
+
+static void input_polldev_stop_workqueue(void)
+{
+ mutex_lock(&polldev_mutex);
+
+ if (!--polldev_users)
+ destroy_workqueue(polldev_wq);
+
+ mutex_unlock(&polldev_mutex);
+}
+
+static void input_polled_device_work(struct work_struct *work)
+{
+ struct input_polled_dev *dev =
+ container_of(work, struct input_polled_dev, work.work);
+
+ dev->poll(dev);
+ queue_delayed_work(polldev_wq, &dev->work,
+ msecs_to_jiffies(dev->poll_interval));
+}
+
+static int input_open_polled_device(struct input_dev *input)
+{
+ struct input_polled_dev *dev = input->private;
+ int error;
+
+ error = input_polldev_start_workqueue();
+ if (error)
+ return error;
+
+ if (dev->flush)
+ dev->flush(dev);
+
+ queue_delayed_work(polldev_wq, &dev->work,
+ msecs_to_jiffies(dev->poll_interval));
+
+ return 0;
+}
+
+static void input_close_polled_device(struct input_dev *input)
+{
+ struct input_polled_dev *dev = input->private;
+
+ cancel_rearming_delayed_workqueue(polldev_wq, &dev->work);
+ input_polldev_stop_workqueue();
+}
+
+/**
+ * input_allocate_polled_device - allocated memory polled device
+ *
+ * The function allocates memory for a polled device and also
+ * for an input device associated with this polled device.
+ */
+struct input_polled_dev *input_allocate_polled_device(void)
+{
+ struct input_polled_dev *dev;
+
+ dev = kzalloc(sizeof(struct input_polled_dev), GFP_KERNEL);
+ if (!dev)
+ return NULL;
+
+ dev->input = input_allocate_device();
+ if (!dev->input) {
+ kfree(dev);
+ return NULL;
+ }
+
+ return dev;
+}
+EXPORT_SYMBOL(input_allocate_polled_device);
+
+/**
+ * input_free_polled_device - free memory allocated for polled device
+ * @dev: device to free
+ *
+ * The function frees memory allocated for polling device and drops
+ * reference to the associated input device (if present).
+ */
+void input_free_polled_device(struct input_polled_dev *dev)
+{
+ if (dev) {
+ input_free_device(dev->input);
+ kfree(dev);
+ }
+}
+EXPORT_SYMBOL(input_free_polled_device);
+
+/**
+ * input_register_polled_device - register polled device
+ * @dev: device to register
+ *
+ * The function registers previously initialized polled input device
+ * with input layer. The device should be allocated with call to
+ * input_allocate_polled_device(). Callers should also set up poll()
+ * method and set up capabilities (id, name, phys, bits) of the
+ * corresponing input_dev structure.
+ */
+int input_register_polled_device(struct input_polled_dev *dev)
+{
+ struct input_dev *input = dev->input;
+
+ INIT_DELAYED_WORK(&dev->work, input_polled_device_work);
+ if (!dev->poll_interval)
+ dev->poll_interval = 500;
+ input->private = dev;
+ input->open = input_open_polled_device;
+ input->close = input_close_polled_device;
+
+ return input_register_device(input);
+}
+EXPORT_SYMBOL(input_register_polled_device);
+
+/**
+ * input_unregister_polled_device - unregister polled device
+ * @dev: device to unregister
+ *
+ * The function unregisters previously registered polled input
+ * device from input layer. Polling is stopped and device is
+ * ready to be freed with call to input_free_polled_device().
+ * Callers should not attempt to access dev->input pointer
+ * after calling this function.
+ */
+void input_unregister_polled_device(struct input_polled_dev *dev)
+{
+ input_unregister_device(dev->input);
+ dev->input = NULL;
+}
+EXPORT_SYMBOL(input_unregister_polled_device);
+