[PATCH] HID: hid-steam: Add Deck IMU support

From: Max Maisel
Date: Sun Apr 07 2024 - 08:20:31 EST

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The Deck's controller features an accelerometer and gyroscope which
send their measurement values by default in the main HID input report.
Expose both sensors to userspace through a separate evdev node as it
is done by the hid-nintendo and hid-playstation drivers.

Signed-off-by: Max Maisel <mmm-1@xxxxxxxxxx>
---

This patch was tested on a Steam Deck running Arch Linux. With it,
applications using latest SDL2/3 git libraries will pick up the sensors
without hidraw access. This was tested against the antimicrox gamepad mapper.

Measurement value scaling was tested by moving the deck and a dualsense
controller simultaneously and comparing their reported values in
userspace with SDL3's testcontroller tool.

drivers/hid/hid-steam.c | 158 ++++++++++++++++++++++++++++++++++++++--
1 file changed, 150 insertions(+), 8 deletions(-)

diff --git a/drivers/hid/hid-steam.c b/drivers/hid/hid-steam.c
index b08a5ab58528..af6e6c3b1356 100644
--- a/drivers/hid/hid-steam.c
+++ b/drivers/hid/hid-steam.c
@@ -66,6 +66,12 @@ static LIST_HEAD(steam_devices);
#define STEAM_DECK_TRIGGER_RESOLUTION 5461
/* Joystick runs are about 5 mm and 32768 units */
#define STEAM_DECK_JOYSTICK_RESOLUTION 6553
+/* Accelerometer has 16 bit resolution and a range of +/- 2g */
+#define STEAM_DECK_ACCEL_RES_PER_G 16384
+#define STEAM_DECK_ACCEL_RANGE 32768
+/* Gyroscope has 16 bit resolution and a range of +/- 2000 dps */
+#define STEAM_DECK_GYRO_RES_PER_DPS 16
+#define STEAM_DECK_GYRO_RANGE 32000

#define STEAM_PAD_FUZZ 256

@@ -288,6 +294,7 @@ struct steam_device {
struct mutex report_mutex;
unsigned long client_opened;
struct input_dev __rcu *input;
+ struct input_dev __rcu *sensors;
unsigned long quirks;
struct work_struct work_connect;
bool connected;
@@ -302,6 +309,7 @@ struct steam_device {
struct work_struct rumble_work;
u16 rumble_left;
u16 rumble_right;
+ unsigned int sensor_timestamp_us;
};

static int steam_recv_report(struct steam_device *steam,
@@ -825,6 +833,74 @@ static int steam_input_register(struct steam_device *steam)
return ret;
}

+static int steam_sensors_register(struct steam_device *steam)
+{
+ struct hid_device *hdev = steam->hdev;
+ struct input_dev *sensors;
+ int ret;
+
+ if (!(steam->quirks & STEAM_QUIRK_DECK))
+ return 0;
+
+ rcu_read_lock();
+ sensors = rcu_dereference(steam->sensors);
+ rcu_read_unlock();
+ if (sensors) {
+ dbg_hid("%s: already connected\n", __func__);
+ return 0;
+ }
+
+ sensors = input_allocate_device();
+ if (!sensors)
+ return -ENOMEM;
+
+ input_set_drvdata(sensors, steam);
+ sensors->dev.parent = &hdev->dev;
+
+ sensors->name = "Steam Deck Motion Sensors";
+ sensors->phys = hdev->phys;
+ sensors->uniq = steam->serial_no;
+ sensors->id.bustype = hdev->bus;
+ sensors->id.vendor = hdev->vendor;
+ sensors->id.product = hdev->product;
+ sensors->id.version = hdev->version;
+
+ __set_bit(INPUT_PROP_ACCELEROMETER, sensors->propbit);
+ __set_bit(EV_MSC, sensors->evbit);
+ __set_bit(MSC_TIMESTAMP, sensors->mscbit);
+
+ input_set_abs_params(sensors, ABS_X, -STEAM_DECK_ACCEL_RANGE,
+ STEAM_DECK_ACCEL_RANGE, 16, 0);
+ input_set_abs_params(sensors, ABS_Y, -STEAM_DECK_ACCEL_RANGE,
+ STEAM_DECK_ACCEL_RANGE, 16, 0);
+ input_set_abs_params(sensors, ABS_Z, -STEAM_DECK_ACCEL_RANGE,
+ STEAM_DECK_ACCEL_RANGE, 16, 0);
+ input_abs_set_res(sensors, ABS_X, STEAM_DECK_ACCEL_RES_PER_G);
+ input_abs_set_res(sensors, ABS_Y, STEAM_DECK_ACCEL_RES_PER_G);
+ input_abs_set_res(sensors, ABS_Z, STEAM_DECK_ACCEL_RES_PER_G);
+
+ input_set_abs_params(sensors, ABS_RX, -STEAM_DECK_GYRO_RANGE,
+ STEAM_DECK_GYRO_RANGE, 16, 0);
+ input_set_abs_params(sensors, ABS_RY, -STEAM_DECK_GYRO_RANGE,
+ STEAM_DECK_GYRO_RANGE, 16, 0);
+ input_set_abs_params(sensors, ABS_RZ, -STEAM_DECK_GYRO_RANGE,
+ STEAM_DECK_GYRO_RANGE, 16, 0);
+ input_abs_set_res(sensors, ABS_RX, STEAM_DECK_GYRO_RES_PER_DPS);
+ input_abs_set_res(sensors, ABS_RY, STEAM_DECK_GYRO_RES_PER_DPS);
+ input_abs_set_res(sensors, ABS_RZ, STEAM_DECK_GYRO_RES_PER_DPS);
+
+ ret = input_register_device(sensors);
+ if (ret)
+ goto sensors_register_fail;
+
+ rcu_assign_pointer(steam->sensors, sensors);
+ return 0;
+
+sensors_register_fail:
+ input_free_device(sensors);
+ return ret;
+}
+
static void steam_input_unregister(struct steam_device *steam)
{
struct input_dev *input;
@@ -838,6 +914,24 @@ static void steam_input_unregister(struct steam_device *steam)
input_unregister_device(input);
}

+static void steam_sensors_unregister(struct steam_device *steam)
+{
+ struct input_dev *sensors;
+
+ if (!(steam->quirks & STEAM_QUIRK_DECK))
+ return;
+
+ rcu_read_lock();
+ sensors = rcu_dereference(steam->sensors);
+ rcu_read_unlock();
+
+ if (!sensors)
+ return;
+ RCU_INIT_POINTER(steam->sensors, NULL);
+ synchronize_rcu();
+ input_unregister_device(sensors);
+}
+
static void steam_battery_unregister(struct steam_device *steam)
{
struct power_supply *battery;
@@ -890,18 +984,28 @@ static int steam_register(struct steam_device *steam)
spin_lock_irqsave(&steam->lock, flags);
client_opened = steam->client_opened;
spin_unlock_irqrestore(&steam->lock, flags);
+
if (!client_opened) {
steam_set_lizard_mode(steam, lizard_mode);
ret = steam_input_register(steam);
- } else
- ret = 0;
+ if (ret != 0)
+ goto steam_register_input_fail;
+ ret = steam_sensors_register(steam);
+ if (ret != 0)
+ goto steam_register_sensors_fail;
+ }
+ return 0;

+steam_register_sensors_fail:
+ steam_input_unregister(steam);
+steam_register_input_fail:
return ret;
}

static void steam_unregister(struct steam_device *steam)
{
steam_battery_unregister(steam);
+ steam_sensors_unregister(steam);
steam_input_unregister(steam);
if (steam->serial_no[0]) {
hid_info(steam->hdev, "Steam Controller '%s' disconnected",
@@ -1010,6 +1114,7 @@ static int steam_client_ll_open(struct hid_device *hdev)
steam->client_opened++;
spin_unlock_irqrestore(&steam->lock, flags);

+ steam_sensors_unregister(steam);
steam_input_unregister(steam);

return 0;
@@ -1030,6 +1135,7 @@ static void steam_client_ll_close(struct hid_device *hdev)
if (connected) {
steam_set_lizard_mode(steam, lizard_mode);
steam_input_register(steam);
+ steam_sensors_register(steam);
}
}

@@ -1121,6 +1227,7 @@ static int steam_probe(struct hid_device *hdev,
INIT_DELAYED_WORK(&steam->mode_switch, steam_mode_switch_cb);
INIT_LIST_HEAD(&steam->list);
INIT_WORK(&steam->rumble_work, steam_haptic_rumble_cb);
+ steam->sensor_timestamp_us = 0;

/*
* With the real steam controller interface, do not connect hidraw.
@@ -1380,12 +1487,12 @@ static void steam_do_input_event(struct steam_device *steam,
* 18-19 | s16 | ABS_HAT0Y | left-pad Y value
* 20-21 | s16 | ABS_HAT1X | right-pad X value
* 22-23 | s16 | ABS_HAT1Y | right-pad Y value
- * 24-25 | s16 | -- | accelerometer X value
- * 26-27 | s16 | -- | accelerometer Y value
- * 28-29 | s16 | -- | accelerometer Z value
- * 30-31 | s16 | -- | gyro X value
- * 32-33 | s16 | -- | gyro Y value
- * 34-35 | s16 | -- | gyro Z value
+ * 24-25 | s16 | IMU ABS_X | accelerometer X value
+ * 26-27 | s16 | IMU ABS_Z | accelerometer Y value
+ * 28-29 | s16 | IMU ABS_Y | accelerometer Z value
+ * 30-31 | s16 | IMU ABS_RX | gyro X value
+ * 32-33 | s16 | IMU ABS_RZ | gyro Y value
+ * 34-35 | s16 | IMU ABS_RY | gyro Z value
* 36-37 | s16 | -- | quaternion W value
* 38-39 | s16 | -- | quaternion X value
* 40-41 | s16 | -- | quaternion Y value
@@ -1546,6 +1653,32 @@ static void steam_do_deck_input_event(struct steam_device *steam,
input_sync(input);
}

+static void steam_do_deck_sensors_event(struct steam_device *steam,
+ struct input_dev *sensors, u8 *data)
+{
+ /*
+ * The deck input report is received every 4 ms on average,
+ * with a jitter of +/- 4 ms even though the USB descriptor claims
+ * that it uses 1 kHz.
+ * Since the HID report does not include a sensor timestamp,
+ * use a fixed increment here.
+ *
+ * The reported sensors data is factory calibrated by default so
+ * no extra logic for handling calibratrion is necessary.
+ */
+ steam->sensor_timestamp_us += 4000;
+ input_event(sensors, EV_MSC, MSC_TIMESTAMP, steam->sensor_timestamp_us);
+
+ input_report_abs(sensors, ABS_X, steam_le16(data + 24));
+ input_report_abs(sensors, ABS_Z, -steam_le16(data + 26));
+ input_report_abs(sensors, ABS_Y, steam_le16(data + 28));
+ input_report_abs(sensors, ABS_RX, steam_le16(data + 30));
+ input_report_abs(sensors, ABS_RZ, -steam_le16(data + 32));
+ input_report_abs(sensors, ABS_RY, steam_le16(data + 34));
+
+ input_sync(sensors);
+}
+
/*
* The size for this message payload is 11.
* The known values are:
@@ -1583,6 +1716,7 @@ static int steam_raw_event(struct hid_device *hdev,
{
struct steam_device *steam = hid_get_drvdata(hdev);
struct input_dev *input;
+ struct input_dev *sensors;
struct power_supply *battery;

if (!steam)
@@ -1629,6 +1763,14 @@ static int steam_raw_event(struct hid_device *hdev,
if (likely(input))
steam_do_deck_input_event(steam, input, data);
rcu_read_unlock();
+
+ if (steam->quirks & STEAM_QUIRK_DECK) {
+ rcu_read_lock();
+ sensors = rcu_dereference(steam->sensors);
+ if (likely(sensors))
+ steam_do_deck_sensors_event(steam, sensors, data);
+ rcu_read_unlock();
+ }
break;
case ID_CONTROLLER_WIRELESS:
/*

base-commit: 39cd87c4eb2b893354f3b850f916353f2658ae6f
--
2.44.0

Next message: Vinod Koul: "Re: [PATCH v8 1/1] dmaengine: switchtec-dma: Introduce Switchtec DMA engine PCI driver"
Previous message: Dominique Martinet: "[PATCH 3/3] perf parse: Allow names to start with digits"
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