HID: add ACRUX game controller force feedback support

Adds force feedback support for ACRUX USB game controllers.
These devices are mass produced in China by several vendors.

Signed-off-by: Sergei Kolzun <x0r@dv-life.ru>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
diff --git a/drivers/hid/hid-axff.c b/drivers/hid/hid-axff.c
new file mode 100644
index 0000000..f42ee14
--- /dev/null
+++ b/drivers/hid/hid-axff.c
@@ -0,0 +1,172 @@
+/*
+ * Force feedback support for ACRUX game controllers
+ *
+ * From what I have gathered, these devices are mass produced in China
+ * by several vendors. They often share the same design as the original
+ * Xbox 360 controller.
+ *
+ * 1a34:0802 "ACRUX USB GAMEPAD 8116"
+ *  - tested with a EXEQ EQ-PCU-02090 game controller.
+ *
+ * Copyright (c) 2010 Sergei Kolzun <x0r@dv-life.ru>
+ */
+
+/*
+ * 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+#include <linux/input.h>
+#include <linux/slab.h>
+#include <linux/usb.h>
+#include <linux/hid.h>
+
+#include "hid-ids.h"
+#include "usbhid/usbhid.h"
+
+struct axff_device {
+	struct hid_report *report;
+};
+
+static int axff_play(struct input_dev *dev, void *data, struct ff_effect *effect)
+{
+	struct hid_device *hid = input_get_drvdata(dev);
+	struct axff_device *axff = data;
+	int left, right;
+
+	left = effect->u.rumble.strong_magnitude;
+	right = effect->u.rumble.weak_magnitude;
+
+	dbg_hid("called with 0x%04x 0x%04x", left, right);
+
+	left = left * 0xff / 0xffff;
+	right = right * 0xff / 0xffff;
+
+	axff->report->field[0]->value[0] = left;
+	axff->report->field[1]->value[0] = right;
+	axff->report->field[2]->value[0] = left;
+	axff->report->field[3]->value[0] = right;
+	dbg_hid("running with 0x%02x 0x%02x", left, right);
+	usbhid_submit_report(hid, axff->report, USB_DIR_OUT);
+
+	return 0;
+}
+
+static int axff_init(struct hid_device *hid)
+{
+	struct axff_device *axff;
+	struct hid_report *report;
+	struct hid_input *hidinput = list_first_entry(&hid->inputs, struct hid_input, list);
+	struct list_head *report_list =&hid->report_enum[HID_OUTPUT_REPORT].report_list;
+	struct input_dev *dev = hidinput->input;
+	int error;
+
+	if (list_empty(report_list)) {
+		dev_err(&hid->dev, "no output reports found\n");
+		return -ENODEV;
+	}
+
+	report = list_first_entry(report_list, struct hid_report, list);
+
+	if (report->maxfield < 4) {
+		dev_err(&hid->dev, "no fields in the report: %d\n", report->maxfield);
+		return -ENODEV;
+	}
+
+	axff = kzalloc(sizeof(struct axff_device), GFP_KERNEL);
+	if (!axff)
+		return -ENOMEM;
+
+	set_bit(FF_RUMBLE, dev->ffbit);
+
+	error = input_ff_create_memless(dev, axff, axff_play);
+	if (error)
+		goto err_free_mem;
+
+	axff->report = report;
+	axff->report->field[0]->value[0] = 0x00;
+	axff->report->field[1]->value[0] = 0x00;
+	axff->report->field[2]->value[0] = 0x00;
+	axff->report->field[3]->value[0] = 0x00;
+	usbhid_submit_report(hid, axff->report, USB_DIR_OUT);
+
+	dev_info(&hid->dev, "Force Feedback for ACRUX game controllers by Sergei Kolzun<x0r@dv-life.ru>\n");
+
+	return 0;
+
+err_free_mem:
+	kfree(axff);
+	return error;
+}
+
+static int ax_probe(struct hid_device *hdev, const struct hid_device_id *id)
+{
+	int error;
+
+	dev_dbg(&hdev->dev, "ACRUX HID hardware probe...");
+
+	error = hid_parse(hdev);
+	if (error) {
+		dev_err(&hdev->dev, "parse failed\n");
+		return error;
+	}
+
+	error = hid_hw_start(hdev, HID_CONNECT_DEFAULT & ~HID_CONNECT_FF);
+	if (error) {
+		dev_err(&hdev->dev, "hw start failed\n");
+		return error;
+	}
+
+	error = axff_init(hdev);
+	if (error) {
+		/*
+		 * Do not fail device initialization completely as device
+		 * may still be partially operable, just warn.
+		 */
+		dev_warn(&hdev->dev,
+			 "Failed to enable force feedback support, error: %d\n",
+			 error);
+	}
+
+	return 0;
+}
+
+static const struct hid_device_id ax_devices[] = {
+	{ HID_USB_DEVICE(USB_VENDOR_ID_ACRUX, 0x0802), },
+	{ }
+};
+MODULE_DEVICE_TABLE(hid, ax_devices);
+
+static struct hid_driver ax_driver = {
+	.name = "acrux",
+	.id_table = ax_devices,
+	.probe = ax_probe,
+};
+
+static int __init ax_init(void)
+{
+	return hid_register_driver(&ax_driver);
+}
+
+static void __exit ax_exit(void)
+{
+	hid_unregister_driver(&ax_driver);
+}
+
+module_init(ax_init);
+module_exit(ax_exit);
+
+MODULE_AUTHOR("Sergei Kolzun");
+MODULE_DESCRIPTION("Force feedback support for ACRUX game controllers");
+MODULE_LICENSE("GPL");