HID: hid-google-stadiaff: add support for Stadia force feedback
Add a hid-google-stadiaff module to support rumble based force feedback
on the Google Stadia controller. This works using the HID output
endpoint exposed on both the USB and BLE interface.
Signed-off-by: Fabio Baltieri <fabiobaltieri@chromium.org>
Reviewed-by: Rahul Rameshbabu <rrameshbabu@nvidia.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
diff --git a/drivers/hid/hid-google-stadiaff.c b/drivers/hid/hid-google-stadiaff.c
new file mode 100644
index 0000000..3731575
--- /dev/null
+++ b/drivers/hid/hid-google-stadiaff.c
@@ -0,0 +1,158 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Stadia controller rumble support.
+ *
+ * Copyright 2023 Google LLC
+ */
+
+#include <linux/hid.h>
+#include <linux/input.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+
+#include "hid-ids.h"
+
+#define STADIA_FF_REPORT_ID 5
+
+struct stadiaff_device {
+ struct hid_device *hid;
+ struct hid_report *report;
+ spinlock_t lock;
+ bool removed;
+ uint16_t strong_magnitude;
+ uint16_t weak_magnitude;
+ struct work_struct work;
+};
+
+static void stadiaff_work(struct work_struct *work)
+{
+ struct stadiaff_device *stadiaff =
+ container_of(work, struct stadiaff_device, work);
+ struct hid_field *rumble_field = stadiaff->report->field[0];
+ unsigned long flags;
+
+ spin_lock_irqsave(&stadiaff->lock, flags);
+ rumble_field->value[0] = stadiaff->strong_magnitude;
+ rumble_field->value[1] = stadiaff->weak_magnitude;
+ spin_unlock_irqrestore(&stadiaff->lock, flags);
+
+ hid_hw_request(stadiaff->hid, stadiaff->report, HID_REQ_SET_REPORT);
+}
+
+static int stadiaff_play(struct input_dev *dev, void *data,
+ struct ff_effect *effect)
+{
+ struct hid_device *hid = input_get_drvdata(dev);
+ struct stadiaff_device *stadiaff = hid_get_drvdata(hid);
+ unsigned long flags;
+
+ spin_lock_irqsave(&stadiaff->lock, flags);
+ if (!stadiaff->removed) {
+ stadiaff->strong_magnitude = effect->u.rumble.strong_magnitude;
+ stadiaff->weak_magnitude = effect->u.rumble.weak_magnitude;
+ schedule_work(&stadiaff->work);
+ }
+ spin_unlock_irqrestore(&stadiaff->lock, flags);
+
+ return 0;
+}
+
+static int stadiaff_init(struct hid_device *hid)
+{
+ struct stadiaff_device *stadiaff;
+ struct hid_report *report;
+ struct hid_input *hidinput;
+ struct input_dev *dev;
+ int error;
+
+ if (list_empty(&hid->inputs)) {
+ hid_err(hid, "no inputs found\n");
+ return -ENODEV;
+ }
+ hidinput = list_entry(hid->inputs.next, struct hid_input, list);
+ dev = hidinput->input;
+
+ report = hid_validate_values(hid, HID_OUTPUT_REPORT,
+ STADIA_FF_REPORT_ID, 0, 2);
+ if (!report)
+ return -ENODEV;
+
+ stadiaff = devm_kzalloc(&hid->dev, sizeof(struct stadiaff_device),
+ GFP_KERNEL);
+ if (!stadiaff)
+ return -ENOMEM;
+
+ hid_set_drvdata(hid, stadiaff);
+
+ input_set_capability(dev, EV_FF, FF_RUMBLE);
+
+ error = input_ff_create_memless(dev, NULL, stadiaff_play);
+ if (error)
+ return error;
+
+ stadiaff->removed = false;
+ stadiaff->hid = hid;
+ stadiaff->report = report;
+ INIT_WORK(&stadiaff->work, stadiaff_work);
+ spin_lock_init(&stadiaff->lock);
+
+ hid_info(hid, "Force Feedback for Google Stadia controller\n");
+
+ return 0;
+}
+
+static int stadia_probe(struct hid_device *hdev, const struct hid_device_id *id)
+{
+ int ret;
+
+ ret = hid_parse(hdev);
+ if (ret) {
+ hid_err(hdev, "parse failed\n");
+ return ret;
+ }
+
+ ret = hid_hw_start(hdev, HID_CONNECT_DEFAULT & ~HID_CONNECT_FF);
+ if (ret) {
+ hid_err(hdev, "hw start failed\n");
+ return ret;
+ }
+
+ ret = stadiaff_init(hdev);
+ if (ret) {
+ hid_err(hdev, "force feedback init failed\n");
+ hid_hw_stop(hdev);
+ return ret;
+ }
+
+ return 0;
+}
+
+static void stadia_remove(struct hid_device *hid)
+{
+ struct stadiaff_device *stadiaff = hid_get_drvdata(hid);
+ unsigned long flags;
+
+ spin_lock_irqsave(&stadiaff->lock, flags);
+ stadiaff->removed = true;
+ spin_unlock_irqrestore(&stadiaff->lock, flags);
+
+ cancel_work_sync(&stadiaff->work);
+ hid_hw_stop(hid);
+}
+
+static const struct hid_device_id stadia_devices[] = {
+ { HID_USB_DEVICE(USB_VENDOR_ID_GOOGLE, USB_DEVICE_ID_GOOGLE_STADIA) },
+ { HID_BLUETOOTH_DEVICE(USB_VENDOR_ID_GOOGLE, USB_DEVICE_ID_GOOGLE_STADIA) },
+ { }
+};
+MODULE_DEVICE_TABLE(hid, stadia_devices);
+
+static struct hid_driver stadia_driver = {
+ .name = "stadia",
+ .id_table = stadia_devices,
+ .probe = stadia_probe,
+ .remove = stadia_remove,
+};
+module_hid_driver(stadia_driver);
+
+MODULE_LICENSE("GPL");
