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/Kconfig b/drivers/hid/Kconfig
index e11c1c8..545e81c 100644 (file)
--- a/drivers/hid/Kconfig
+++ b/drivers/hid/Kconfig
@@ -412,6 +412,13 @@ config HID_GOOGLE_HAMMER
        help
        Say Y here if you have a Google Hammer device.
 
+config HID_GOOGLE_STADIA_FF
+       tristate "Google Stadia force feedback"
+       select INPUT_FF_MEMLESS
+       help
+       Say Y here if you want to enable force feedback support for the Google
+       Stadia controller.
+
 config HID_VIVALDI
        tristate "Vivaldi Keyboard"
        select HID_VIVALDI_COMMON

diff --git a/drivers/hid/Makefile b/drivers/hid/Makefile
index 7a9e160..8a06d0f 100644 (file)
--- a/drivers/hid/Makefile
+++ b/drivers/hid/Makefile
@@ -55,6 +55,7 @@ obj-$(CONFIG_HID_GFRM)                += hid-gfrm.o
 obj-$(CONFIG_HID_GLORIOUS)  += hid-glorious.o
 obj-$(CONFIG_HID_VIVALDI_COMMON) += hid-vivaldi-common.o
 obj-$(CONFIG_HID_GOOGLE_HAMMER)        += hid-google-hammer.o
+obj-$(CONFIG_HID_GOOGLE_STADIA_FF)     += hid-google-stadiaff.o
 obj-$(CONFIG_HID_VIVALDI)      += hid-vivaldi.o
 obj-$(CONFIG_HID_GT683R)       += hid-gt683r.o
 obj-$(CONFIG_HID_GYRATION)     += hid-gyration.o

diff --git a/drivers/hid/hid-google-stadiaff.c b/drivers/hid/hid-google-stadiaff.c
new file mode 100644 (file)
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");

diff --git a/drivers/hid/hid-ids.h b/drivers/hid/hid-ids.h
index 8a310f8..42c43d3 100644 (file)
--- a/drivers/hid/hid-ids.h
+++ b/drivers/hid/hid-ids.h
@@ -531,6 +531,7 @@
 #define USB_DEVICE_ID_GOOGLE_DON       0x5050
 #define USB_DEVICE_ID_GOOGLE_EEL       0x5057
 #define USB_DEVICE_ID_GOOGLE_JEWEL     0x5061
+#define USB_DEVICE_ID_GOOGLE_STADIA    0x9400
 
 #define USB_VENDOR_ID_GOTOP            0x08f2
 #define USB_DEVICE_ID_SUPER_Q2         0x007f