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From:   Emmanuel Gil Peyrot <linkmauve@linkmauve.fr>
To:     linux-input@vger.kernel.org
Cc:     Emmanuel Gil Peyrot <linkmauve@linkmauve.fr>,
        Ash Logan <ash@heyquark.com>,
        =?UTF-8?q?Jonathan=20Neusch=C3=A4fer?= <j.ne@posteo.net>,
        =?UTF-8?q?Barnab=C3=A1s=20P=C5=91cze?= <pobrn@protonmail.com>,
        Jiri Kosina <jikos@kernel.org>,
        Benjamin Tissoires <benjamin.tissoires@redhat.com>,
        linux-kernel@vger.kernel.org
Subject: [PATCH v3 3/4] HID: wiiu-drc: Add accelerometer, gyroscope and magnetometer readings
Date:   Wed, 19 May 2021 10:59:23 +0200
Message-Id: <20210519085924.1636-4-linkmauve@linkmauve.fr>
In-Reply-To: <20210519085924.1636-1-linkmauve@linkmauve.fr>
References: <20210502232836.26134-1-linkmauve@linkmauve.fr>
 <20210519085924.1636-1-linkmauve@linkmauve.fr>
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These are mostly untested so far, because I have no idea which userland
to test against, but evtest at least seems to give sensible values.

The magnetometer doesn’t have dedicated INPUT_PROP_ACCELEROMETER
buttons, so I used three clearly invalid absolute values, in the hope
that someone will fix that eventually.  Another solution might be to go
for the iio subsystem instead, but then it wouldn’t be tied to the HID
any longer and I would feel uneasy about that.  Especially because
multiple such gamepads could be connected to a single computer.

Signed-off-by: Ash Logan <ash@heyquark.com>
Signed-off-by: Emmanuel Gil Peyrot <linkmauve@linkmauve.fr>
---
 drivers/hid/hid-wiiu-drc.c | 77 ++++++++++++++++++++++++++++++++++++--
 1 file changed, 74 insertions(+), 3 deletions(-)

diff --git a/drivers/hid/hid-wiiu-drc.c b/drivers/hid/hid-wiiu-drc.c
index a5d347d5f662..0cf5b657fec9 100644
--- a/drivers/hid/hid-wiiu-drc.c
+++ b/drivers/hid/hid-wiiu-drc.c
@@ -63,15 +63,25 @@
 #define TOUCH_BORDER_X	100
 #define TOUCH_BORDER_Y	200
 
+/* Accelerometer, gyroscope and magnetometer constants */
+#define ACCEL_MIN	-(1 << 15)
+#define ACCEL_MAX	((1 << 15) - 1)
+#define GYRO_MIN	-(1 << 23)
+#define GYRO_MAX	((1 << 23) - 1)
+#define MAGNET_MIN	-(1 << 15)
+#define MAGNET_MAX	((1 << 15) - 1)
+
 /*
  * The device is setup with multiple input devices:
  * - A joypad with the buttons and sticks.
  * - The touch area which works as a touchscreen.
+ * - An accelerometer + gyroscope + magnetometer device.
  */
 
 struct drc {
 	struct input_dev *joy_input_dev;
 	struct input_dev *touch_input_dev;
+	struct input_dev *accel_input_dev;
 	struct hid_device *hdev;
 };
 
@@ -87,7 +97,7 @@ static int drc_raw_event(struct hid_device *hdev, struct hid_report *report,
 			 u8 *data, int len)
 {
 	struct drc *drc = hid_get_drvdata(hdev);
-	int i, x, y, pressure, base;
+	int i, x, y, z, pressure, base;
 	u32 buttons;
 
 	if (len != 128)
@@ -182,6 +192,31 @@ static int drc_raw_event(struct hid_device *hdev, struct hid_report *report,
 	}
 	input_sync(drc->touch_input_dev);
 
+	/* accelerometer */
+	x = (data[16] << 8) | data[15];
+	y = (data[18] << 8) | data[17];
+	z = (data[20] << 8) | data[19];
+	input_report_abs(drc->accel_input_dev, ABS_X, (int16_t)x);
+	input_report_abs(drc->accel_input_dev, ABS_Y, (int16_t)y);
+	input_report_abs(drc->accel_input_dev, ABS_Z, (int16_t)z);
+
+	/* gyroscope */
+	x = (data[23] << 24) | (data[22] << 16) | (data[21] << 8);
+	y = (data[26] << 24) | (data[25] << 16) | (data[24] << 8);
+	z = (data[29] << 24) | (data[28] << 16) | (data[27] << 8);
+	input_report_abs(drc->accel_input_dev, ABS_RX, x >> 8);
+	input_report_abs(drc->accel_input_dev, ABS_RY, y >> 8);
+	input_report_abs(drc->accel_input_dev, ABS_RZ, z >> 8);
+
+	/* magnetometer */
+	x = (data[31] << 8) | data[30];
+	y = (data[33] << 8) | data[32];
+	z = (data[35] << 8) | data[34];
+	input_report_abs(drc->accel_input_dev, ABS_THROTTLE, (int16_t)x);
+	input_report_abs(drc->accel_input_dev, ABS_RUDDER, (int16_t)y);
+	input_report_abs(drc->accel_input_dev, ABS_WHEEL, (int16_t)z);
+	input_sync(drc->accel_input_dev);
+
 	/* let hidraw and hiddev handle the report */
 	return 0;
 }
@@ -297,6 +332,40 @@ static bool drc_setup_touch(struct drc *drc,
 	return true;
 }
 
+static bool drc_setup_accel(struct drc *drc,
+			    struct hid_device *hdev)
+{
+	struct input_dev *input_dev;
+
+	input_dev = allocate_and_setup(hdev, DEVICE_NAME " accelerometer, gyroscope and magnetometer");
+	if (!input_dev)
+		return false;
+
+	drc->accel_input_dev = input_dev;
+
+	set_bit(INPUT_PROP_ACCELEROMETER, input_dev->propbit);
+
+	/* 1G accel is reported as about -7900 */
+	input_set_abs_params(input_dev, ABS_X, ACCEL_MIN, ACCEL_MAX, 0, 0);
+	input_set_abs_params(input_dev, ABS_Y, ACCEL_MIN, ACCEL_MAX, 0, 0);
+	input_set_abs_params(input_dev, ABS_Z, ACCEL_MIN, ACCEL_MAX, 0, 0);
+
+	/* gyroscope */
+	input_set_abs_params(input_dev, ABS_RX, GYRO_MIN, GYRO_MAX, 0, 0);
+	input_set_abs_params(input_dev, ABS_RY, GYRO_MIN, GYRO_MAX, 0, 0);
+	input_set_abs_params(input_dev, ABS_RZ, GYRO_MIN, GYRO_MAX, 0, 0);
+
+	/* magnetometer */
+	/* TODO: Figure out which ABS_* would make more sense to expose, or
+	 * maybe go for the iio subsystem?
+	 */
+	input_set_abs_params(input_dev, ABS_THROTTLE, MAGNET_MIN, MAGNET_MAX, 0, 0);
+	input_set_abs_params(input_dev, ABS_RUDDER, MAGNET_MIN, MAGNET_MAX, 0, 0);
+	input_set_abs_params(input_dev, ABS_WHEEL, MAGNET_MIN, MAGNET_MAX, 0, 0);
+
+	return true;
+}
+
 static int drc_probe(struct hid_device *hdev, const struct hid_device_id *id)
 {
 	struct drc *drc;
@@ -317,7 +386,8 @@ static int drc_probe(struct hid_device *hdev, const struct hid_device_id *id)
 	}
 
 	if (!drc_setup_joypad(drc, hdev) ||
-	    !drc_setup_touch(drc, hdev)) {
+	    !drc_setup_touch(drc, hdev) ||
+	    !drc_setup_accel(drc, hdev)) {
 		hid_err(hdev, "could not allocate interfaces\n");
 		return -ENOMEM;
 	}
@@ -329,7 +399,8 @@ static int drc_probe(struct hid_device *hdev, const struct hid_device_id *id)
 	}
 
 	ret = input_register_device(drc->joy_input_dev) ||
-	      input_register_device(drc->touch_input_dev);
+	      input_register_device(drc->touch_input_dev) ||
+	      input_register_device(drc->accel_input_dev);
 	if (ret) {
 		hid_err(hdev, "failed to register interfaces\n");
 		return ret;
-- 
2.31.1