1 files changed, 130 insertions, 0 deletions
diff --git a/drivers/hid/hid-wiimote-ext.c b/drivers/hid/hid-wiimote-ext.c
new file mode 100644
index 000000000000..fa9c67722aca
--- /dev/null
+++ b/drivers/hid/hid-wiimote-ext.c
@@ -0,0 +1,130 @@
+/*
+ * HID driver for Nintendo Wiimote extension devices
+ * Copyright (c) 2011 David Herrmann
+ */
+
+/*
+ * 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.
+ */
+
+#include <linux/atomic.h>
+#include <linux/module.h>
+#include <linux/spinlock.h>
+#include <linux/workqueue.h>
+#include "hid-wiimote.h"
+
+struct wiimote_ext {
+	struct wiimote_data *wdata;
+	struct work_struct worker;
+
+	atomic_t opened;
+	atomic_t mp_opened;
+	bool plugged;
+	bool motionp;
+	__u8 ext_type;
+};
+
+enum wiiext_type {
+	WIIEXT_NONE,		/* placeholder */
+	WIIEXT_CLASSIC,		/* Nintendo classic controller */
+	WIIEXT_NUNCHUCK,	/* Nintendo nunchuck controller */
+};
+
+static void wiiext_worker(struct work_struct *work)
+{
+	struct wiimote_ext *ext = container_of(work, struct wiimote_ext,
+									worker);
+}
+
+/* schedule work only once, otherwise mark for reschedule */
+static void wiiext_schedule(struct wiimote_ext *ext)
+{
+	queue_work(system_nrt_wq, &ext->worker);
+}
+
+/*
+ * Reacts on extension port events
+ * Whenever the driver gets an event from the wiimote that an extension has been
+ * plugged or unplugged, this funtion shall be called. It checks what extensions
+ * are connected and initializes and activates them.
+ * This can be called in atomic context. The initialization is done in a
+ * separate worker thread. The state.lock spinlock must be held by the caller.
+ */
+void wiiext_event(struct wiimote_data *wdata, bool plugged)
+{
+	if (!wdata->ext)
+		return;
+
+	if (wdata->ext->plugged == plugged)
+		return;
+
+	wdata->ext->plugged = plugged;
+	/*
+	 * We need to call wiiext_schedule(wdata->ext) here, however, the
+	 * extension initialization logic is not fully understood and so
+	 * automatic initialization is not supported, yet.
+	 */
+}
+
+/*
+ * Returns true if the current DRM mode should contain extension data and false
+ * if there is no interest in extension data.
+ * All supported extensions send 6 byte extension data so any DRM that contains
+ * extension bytes is fine.
+ * The caller must hold the state.lock spinlock.
+ */
+bool wiiext_active(struct wiimote_data *wdata)
+{
+	if (!wdata->ext)
+		return false;
+
+	return wdata->ext->motionp || wdata->ext->ext_type;
+}
+
+/* Initializes the extension driver of a wiimote */
+int wiiext_init(struct wiimote_data *wdata)
+{
+	struct wiimote_ext *ext;
+	unsigned long flags;
+
+	ext = kzalloc(sizeof(*ext), GFP_KERNEL);
+	if (!ext)
+		return -ENOMEM;
+
+	ext->wdata = wdata;
+	INIT_WORK(&ext->worker, wiiext_worker);
+
+	spin_lock_irqsave(&wdata->state.lock, flags);
+	wdata->ext = ext;
+	spin_unlock_irqrestore(&wdata->state.lock, flags);
+
+	return 0;
+}
+
+/* Deinitializes the extension driver of a wiimote */
+void wiiext_deinit(struct wiimote_data *wdata)
+{
+	struct wiimote_ext *ext = wdata->ext;
+	unsigned long flags;
+
+	if (!ext)
+		return;
+
+	/*
+	 * We first unset wdata->ext to avoid further input from the wiimote
+	 * core. The worker thread does not access this pointer so it is not
+	 * affected by this.
+	 * We kill the worker after this so it does not get respawned during
+	 * deinitialization.
+	 */
+
+	spin_lock_irqsave(&wdata->state.lock, flags);
+	wdata->ext = NULL;
+	spin_unlock_irqrestore(&wdata->state.lock, flags);
+
+	cancel_work_sync(&ext->worker);
+	kfree(ext);
+}