[PATCH 1/2] Alps HID I2C T4 device support

[Masaki Ota]

>From Masaki Ota <masai.ota@xxxxxxxxxxx>

-Support Alps HID I2C T4 Touchpad device.
-Laptop names that use this Touchpad:HP Zbook Studio, Elitebook Folio G1, Elitebook 1030 G1, Elitebook 1040 G3

Signed-off-by: Masaki Ota <masaki.ota@xxxxxxxxxxx>
---
 drivers/hid/hid-alps.c | 500 +++++++++++++++++++++++++++++++++++++++----------
 drivers/hid/hid-core.c |   3 +-
 drivers/hid/hid-ids.h  |   1 +
 3 files changed, 403 insertions(+), 101 deletions(-)

diff --git a/drivers/hid/hid-alps.c b/drivers/hid/hid-alps.c
index ed9c0ea..13a6db1 100644
--- a/drivers/hid/hid-alps.c
+++ b/drivers/hid/hid-alps.c
@@ -52,8 +52,30 @@
 #define ADDRESS_U1_PAD_BTN		0x00800052
 #define ADDRESS_U1_SP_BTN		0x0080009F
 
+#define T4_INPUT_REPORT_LEN			sizeof(T4_INPUT_REPORT)
+#define T4_FEATURE_REPORT_LEN		T4_INPUT_REPORT_LEN
+#define T4_FEATURE_REPORT_ID		7
+#define T4_CMD_REGISTER_READ			0x08
+#define T4_CMD_REGISTER_WRITE			0x07
+
+#define T4_ADDRESS_BASE				0xC2C0
+#define PRM_SYS_CONFIG_1			(T4_ADDRESS_BASE + 0x0002)
+#define T4_PRM_FEED_CONFIG_1		(T4_ADDRESS_BASE + 0x0004)
+#define T4_PRM_FEED_CONFIG_4		(T4_ADDRESS_BASE + 0x001A)
+#define T4_PRM_ID_CONFIG_3			(T4_ADDRESS_BASE + 0x00B0)
+
+
+#define T4_FEEDCFG4_ADVANCED_ABS_ENABLE			0x01
+#define T4_I2C_ABS	0x78
+
+#define T4_COUNT_PER_ELECTRODE		256
 #define MAX_TOUCHES	5
 
+typedef enum {
+	U1,
+	T4,
+	UNKNOWN,
+} DEV_TYPE;
 /**
  * struct u1_data
  *
@@ -61,43 +83,168 @@
  * @input2: pointer to the kernel input2 device
  * @hdev: pointer to the struct hid_device
  *
- * @dev_ctrl: device control parameter
  * @dev_type: device type
- * @sen_line_num_x: number of sensor line of X
- * @sen_line_num_y: number of sensor line of Y
- * @pitch_x: sensor pitch of X
- * @pitch_y: sensor pitch of Y
- * @resolution: resolution
- * @btn_info: button information
+ * @max_fingers: total number of fingers
+ * @has_sp: boolean of sp existense
+ * @sp_btn_info: button information
  * @x_active_len_mm: active area length of X (mm)
  * @y_active_len_mm: active area length of Y (mm)
  * @x_max: maximum x coordinate value
  * @y_max: maximum y coordinate value
+ * @x_min: minimum x coordinate value
+ * @y_min: minimum y coordinate value
  * @btn_cnt: number of buttons
  * @sp_btn_cnt: number of stick buttons
  */
-struct u1_dev {
+struct alps_dev {
 	struct input_dev *input;
 	struct input_dev *input2;
 	struct hid_device *hdev;
 
-	u8	dev_ctrl;
-	u8	dev_type;
-	u8	sen_line_num_x;
-	u8	sen_line_num_y;
-	u8	pitch_x;
-	u8	pitch_y;
-	u8	resolution;
-	u8	btn_info;
+	DEV_TYPE dev_type;
+	u8  max_fingers;
+	u8  has_sp;
 	u8	sp_btn_info;
 	u32	x_active_len_mm;
 	u32	y_active_len_mm;
 	u32	x_max;
 	u32	y_max;
+	u32	x_min;
+	u32	y_min;
 	u32	btn_cnt;
 	u32	sp_btn_cnt;
 };
 
+typedef struct _T4_CONTACT_DATA {
+	u8  Palm;
+	u8	x_lo;
+	u8	x_hi;
+	u8	y_lo;
+	u8	y_hi;
+} T4_CONTACT_DATA, *PT4_CONTACT_DATA;
+
+typedef struct _T4_INPUT_REPORT {
+	u8  ReportID;
+	u8  NumContacts;
+	T4_CONTACT_DATA Contact[5];
+	u8  Button;
+	u8  Track[5];
+	u8  ZX[5], ZY[5];
+	u8  PalmTime[5];
+	u8  Kilroy;
+	u16 TimeStamp;
+} T4_INPUT_REPORT, *PT4_INPUT_REPORT;
+
+static u16 t4_calc_check_sum(u8 *buffer,
+		unsigned long offset, unsigned long length)
+{
+	u16 sum1 = 0xFF, sum2 = 0xFF;
+	unsigned long i = 0;
+
+	if (offset + length >= 50)
+		return 0;
+
+	while (length > 0) {
+		u32 tlen = length > 20 ? 20 : length;
+
+		length -= tlen;
+
+		do {
+			sum1 += buffer[offset + i];
+			sum2 += sum1;
+			i++;
+		} while (--tlen > 0);
+
+		sum1 = (sum1 & 0xFF) + (sum1 >> 8);
+		sum2 = (sum2 & 0xFF) + (sum2 >> 8);
+	}
+
+	sum1 = (sum1 & 0xFF) + (sum1 >> 8);
+	sum2 = (sum2 & 0xFF) + (sum2 >> 8);
+
+	return(sum2 << 8 | sum1);
+}
+
+static int T4_read_write_register(struct hid_device *hdev, u32 address,
+	u8 *read_val, u8 write_val, bool read_flag)
+{
+	int ret;
+	u16 check_sum;
+	u8 *input;
+	u8 *readbuf;
+
+	input = kzalloc(T4_FEATURE_REPORT_LEN, GFP_KERNEL);
+	if (!input)
+		return -ENOMEM;
+
+	input[0] = T4_FEATURE_REPORT_ID;
+	if (read_flag) {
+		input[1] = T4_CMD_REGISTER_READ;
+		input[8] = 0x00;
+	} else {
+		input[1] = T4_CMD_REGISTER_WRITE;
+		input[8] = write_val;
+	}
+	put_unaligned_le32(address, input + 2);
+	//input[4] = 0;
+	//input[5] = 0;
+	input[6] = 1;
+	input[7] = 0;
+
+	// Calculate amd append the checksum
+	check_sum = t4_calc_check_sum(input, 1, 8);
+	input[9] = (u8)check_sum;
+	input[10] = (u8)(check_sum >> 8);
+	input[11] = 0;
+
+	ret = hid_hw_raw_request(hdev, T4_FEATURE_REPORT_ID, input,
+			T4_FEATURE_REPORT_LEN,
+			HID_FEATURE_REPORT, HID_REQ_SET_REPORT);
+
+	if (ret < 0) {
+		dev_err(&hdev->dev, "failed to read command (%d)\n", ret);
+		goto exit;
+	}
+
+	if (read_flag) {
+		readbuf = kzalloc(T4_FEATURE_REPORT_LEN, GFP_KERNEL);
+		if (!readbuf) {
+			kfree(input);
+			return -ENOMEM;
+		}
+
+		ret = hid_hw_raw_request(hdev, T4_FEATURE_REPORT_ID, readbuf,
+				T4_FEATURE_REPORT_LEN,
+				HID_FEATURE_REPORT, HID_REQ_GET_REPORT);
+		if (ret < 0) {
+			dev_err(&hdev->dev, "failed read register (%d)\n", ret);
+			goto exit;
+		}
+		if (*(u32 *)&readbuf[6] != address)
+			hid_alert(hdev, "T4_read_write_register address error %x %x\n",
+				*(u32 *)&readbuf[6], address);
+
+		if (*(u16 *)&readbuf[10] != 1)
+			hid_alert(hdev, "T4_read_write_register size error %x\n",
+				*(u16 *)&readbuf[10]);
+
+		check_sum = t4_calc_check_sum(readbuf, 6, 7);
+		if (*(u16 *)&readbuf[13] != check_sum)
+			hid_alert(hdev, "T4_read_write_register checksum error %x %x\n",
+				*(u16 *)&readbuf[13], check_sum);
+
+		*read_val = readbuf[12];
+
+		kfree(readbuf);
+	}
+
+	ret = 0;
+
+exit:
+	kfree(input);
+	return ret;
+}
+
 static int u1_read_write_register(struct hid_device *hdev, u32 address,
 	u8 *read_val, u8 write_val, bool read_flag)
 {
@@ -165,21 +312,63 @@ static int u1_read_write_register(struct hid_device *hdev, u32 address,
 	return ret;
 }
 
-static int alps_raw_event(struct hid_device *hdev,
-		struct hid_report *report, u8 *data, int size)
+static int T4_raw_event(struct alps_dev *hdata, u8 *data, int size)
+{
+	unsigned int x, y, z;
+	int i;
+	PT4_INPUT_REPORT p_report = (PT4_INPUT_REPORT)data;
+
+	if (!data)
+		return 0;
+	for (i = 0; i < hdata->max_fingers; i++) {
+		x = p_report->Contact[i].x_hi<<8 | p_report->Contact[i].x_lo;
+		y = p_report->Contact[i].y_hi<<8 | p_report->Contact[i].y_lo;
+		y = hdata->y_max - y + hdata->y_min;
+		z = (p_report->Contact[i].Palm < 0x80 &&
+			p_report->Contact[i].Palm > 0) * 62;
+		if (x == 0xffff) {
+			x = 0;
+			y = 0;
+			z = 0;
+		}
+		input_mt_slot(hdata->input, i);
+
+		if (z != 0) {
+			input_mt_report_slot_state(hdata->input,
+				MT_TOOL_FINGER, 1);
+		} else {
+			input_mt_report_slot_state(hdata->input,
+				MT_TOOL_FINGER, 0);
+			continue;
+		}
+
+		input_report_abs(hdata->input, ABS_MT_POSITION_X, x);
+		input_report_abs(hdata->input, ABS_MT_POSITION_Y, y);
+		input_report_abs(hdata->input, ABS_MT_PRESSURE, z);
+	}
+	input_mt_sync_frame(hdata->input);
+
+	input_report_key(hdata->input, BTN_LEFT,	p_report->Button);
+
+	input_sync(hdata->input);
+	return 1;
+}
+
+static int U1_raw_event(struct alps_dev *hdata, u8 *data, int size)
 {
 	unsigned int x, y, z;
 	int i;
 	short sp_x, sp_y;
-	struct u1_dev *hdata = hid_get_drvdata(hdev);
 
+	if (!data)
+		return 0;
 	switch (data[0]) {
 	case U1_MOUSE_REPORT_ID:
 		break;
 	case U1_FEATURE_REPORT_ID:
 		break;
 	case U1_ABSOLUTE_REPORT_ID:
-		for (i = 0; i < MAX_TOUCHES; i++) {
+		for (i = 0; i < hdata->max_fingers; i++) {
 			u8 *contact = &data[i * 5];
 
 			x = get_unaligned_le16(contact + 3);
@@ -241,122 +430,246 @@ static int alps_raw_event(struct hid_device *hdev,
 	return 0;
 }
 
+static int alps_raw_event(struct hid_device *hdev,
+		struct hid_report *report, u8 *data, int size)
+{
+	int ret = 0;
+	struct alps_dev *hdata = hid_get_drvdata(hdev);
+
+	if (hdev->product == HID_PRODUCT_ID_T4_BTNLESS)
+		ret = T4_raw_event(hdata, data, size);
+	else
+		ret = U1_raw_event(hdata, data, size);
+
+	return ret;
+}
+
 #ifdef CONFIG_PM
 static int alps_post_reset(struct hid_device *hdev)
 {
-	return u1_read_write_register(hdev, ADDRESS_U1_DEV_CTRL_1,
-				NULL, U1_TP_ABS_MODE | U1_SP_ABS_MODE, false);
+	int ret = -1;
+	struct alps_dev *data = hid_get_drvdata(hdev);
+
+	switch (data->dev_type) {
+	case T4:
+		ret = T4_read_write_register(hdev, T4_PRM_FEED_CONFIG_1,
+			NULL, T4_I2C_ABS, false);
+		ret = T4_read_write_register(hdev, T4_PRM_FEED_CONFIG_4,
+			NULL, T4_FEEDCFG4_ADVANCED_ABS_ENABLE, false);
+		break;
+	case U1:
+		ret = u1_read_write_register(hdev,
+			ADDRESS_U1_DEV_CTRL_1, NULL,
+			U1_TP_ABS_MODE | U1_SP_ABS_MODE, false);
+		break;
+	default:
+		break;
+	}
+	return ret;
 }
 
 static int alps_post_resume(struct hid_device *hdev)
 {
-	return u1_read_write_register(hdev, ADDRESS_U1_DEV_CTRL_1,
-				NULL, U1_TP_ABS_MODE | U1_SP_ABS_MODE, false);
+	return alps_post_reset(hdev);
 }
 #endif /* CONFIG_PM */
 
-static int alps_input_configured(struct hid_device *hdev, struct hid_input *hi)
+static int u1_init(struct hid_device *hdev, struct alps_dev *pri_data)
 {
-	struct u1_dev *data = hid_get_drvdata(hdev);
-	struct input_dev *input = hi->input, *input2;
-	struct u1_dev devInfo;
 	int ret;
-	int res_x, res_y, i;
-
-	data->input = input;
-
-	hid_dbg(hdev, "Opening low level driver\n");
-	ret = hid_hw_open(hdev);
-	if (ret)
-		return ret;
-
-	/* Allow incoming hid reports */
-	hid_device_io_start(hdev);
+	u8 tmp, dev_ctrl, sen_line_num_x, sen_line_num_y;
+	u8 pitch_x, pitch_y, resolution;
 
 	/* Device initialization */
 	ret = u1_read_write_register(hdev, ADDRESS_U1_DEV_CTRL_1,
-			&devInfo.dev_ctrl, 0, true);
+			&dev_ctrl, 0, true);
 	if (ret < 0) {
 		dev_err(&hdev->dev, "failed U1_DEV_CTRL_1 (%d)\n", ret);
 		goto exit;
 	}
 
-	devInfo.dev_ctrl &= ~U1_DISABLE_DEV;
-	devInfo.dev_ctrl |= U1_TP_ABS_MODE;
+	dev_ctrl &= ~U1_DISABLE_DEV;
+	dev_ctrl |= U1_TP_ABS_MODE;
 	ret = u1_read_write_register(hdev, ADDRESS_U1_DEV_CTRL_1,
-			NULL, devInfo.dev_ctrl, false);
+			NULL, dev_ctrl, false);
 	if (ret < 0) {
 		dev_err(&hdev->dev, "failed to change TP mode (%d)\n", ret);
 		goto exit;
 	}
 
 	ret = u1_read_write_register(hdev, ADDRESS_U1_NUM_SENS_X,
-			&devInfo.sen_line_num_x, 0, true);
+			&sen_line_num_x, 0, true);
 	if (ret < 0) {
 		dev_err(&hdev->dev, "failed U1_NUM_SENS_X (%d)\n", ret);
 		goto exit;
 	}
 
 	ret = u1_read_write_register(hdev, ADDRESS_U1_NUM_SENS_Y,
-			&devInfo.sen_line_num_y, 0, true);
+			&sen_line_num_y, 0, true);
 		if (ret < 0) {
 		dev_err(&hdev->dev, "failed U1_NUM_SENS_Y (%d)\n", ret);
 		goto exit;
 	}
 
 	ret = u1_read_write_register(hdev, ADDRESS_U1_PITCH_SENS_X,
-			&devInfo.pitch_x, 0, true);
+			&pitch_x, 0, true);
 	if (ret < 0) {
 		dev_err(&hdev->dev, "failed U1_PITCH_SENS_X (%d)\n", ret);
 		goto exit;
 	}
 
 	ret = u1_read_write_register(hdev, ADDRESS_U1_PITCH_SENS_Y,
-			&devInfo.pitch_y, 0, true);
+			&pitch_y, 0, true);
 	if (ret < 0) {
 		dev_err(&hdev->dev, "failed U1_PITCH_SENS_Y (%d)\n", ret);
 		goto exit;
 	}
 
 	ret = u1_read_write_register(hdev, ADDRESS_U1_RESO_DWN_ABS,
-		&devInfo.resolution, 0, true);
+		&resolution, 0, true);
 	if (ret < 0) {
 		dev_err(&hdev->dev, "failed U1_RESO_DWN_ABS (%d)\n", ret);
 		goto exit;
 	}
+	pri_data->x_active_len_mm =
+		(pitch_x * (sen_line_num_x - 1)) / 10;
+	pri_data->y_active_len_mm =
+		(pitch_y * (sen_line_num_y - 1)) / 10;
+
+	pri_data->x_max =
+		(resolution << 2) * (sen_line_num_x - 1);
+	pri_data->x_min = 1;
+	pri_data->y_max =
+		(resolution << 2) * (sen_line_num_y - 1);
+	pri_data->y_min = 1;
 
 	ret = u1_read_write_register(hdev, ADDRESS_U1_PAD_BTN,
-			&devInfo.btn_info, 0, true);
+			&tmp, 0, true);
 	if (ret < 0) {
 		dev_err(&hdev->dev, "failed U1_PAD_BTN (%d)\n", ret);
 		goto exit;
 	}
+	if ((tmp & 0x0F) == (tmp & 0xF0) >> 4) {
+		pri_data->btn_cnt = (tmp & 0x0F);
+	} else {
+		/* Button pad */
+		pri_data->btn_cnt = 1;
+	}
 
+	pri_data->has_sp = 0;
 	/* Check StickPointer device */
 	ret = u1_read_write_register(hdev, ADDRESS_U1_DEVICE_TYP,
-			&devInfo.dev_type, 0, true);
+			&tmp, 0, true);
 	if (ret < 0) {
 		dev_err(&hdev->dev, "failed U1_DEVICE_TYP (%d)\n", ret);
 		goto exit;
 	}
+	if (tmp & U1_DEVTYPE_SP_SUPPORT) {
+		dev_ctrl |= U1_SP_ABS_MODE;
+		ret = u1_read_write_register(hdev, ADDRESS_U1_DEV_CTRL_1,
+			NULL, dev_ctrl, false);
+		if (ret < 0) {
+			dev_err(&hdev->dev, "failed SP mode (%d)\n", ret);
+			goto exit;
+		}
+
+		ret = u1_read_write_register(hdev, ADDRESS_U1_SP_BTN,
+			&pri_data->sp_btn_info, 0, true);
+		if (ret < 0) {
+			dev_err(&hdev->dev, "failed U1_SP_BTN (%d)\n", ret);
+			goto exit;
+		}
+		pri_data->has_sp = 1;
+	}
+	pri_data->max_fingers = 5;
+exit:
+	return ret;
+}
+
+static int T4_init(struct hid_device *hdev, struct alps_dev *pri_data)
+{
+	int ret;
+	u8 tmp, sen_line_num_x, sen_line_num_y;
+
+	ret = T4_read_write_register(hdev, T4_PRM_ID_CONFIG_3, &tmp, 0, true);
+	if (ret < 0) {
+		dev_err(&hdev->dev, "failed T4_PRM_ID_CONFIG_3 (%d)\n", ret);
+		goto exit;
+	}
+	sen_line_num_x = 16+((tmp & 0x0F)  | (tmp & 0x08 ? 0xF0 : 0));
+	sen_line_num_y = 12+(((tmp & 0xF0) >> 4)  | (tmp & 0x80 ? 0xF0 : 0));
+
+	pri_data->x_max = sen_line_num_x * T4_COUNT_PER_ELECTRODE;
+	pri_data->x_min = T4_COUNT_PER_ELECTRODE;
+	pri_data->y_max = sen_line_num_y * T4_COUNT_PER_ELECTRODE;
+	pri_data->y_min = T4_COUNT_PER_ELECTRODE;
+	pri_data->x_active_len_mm = pri_data->y_active_len_mm = 0;
+	pri_data->btn_cnt = 1;
+
+	ret = T4_read_write_register(hdev, PRM_SYS_CONFIG_1, &tmp, 0, true);
+	if (ret < 0) {
+		dev_err(&hdev->dev, "failed PRM_SYS_CONFIG_1 (%d)\n", ret);
+		goto exit;
+	}
+	tmp |= 0x02;
+	ret = T4_read_write_register(hdev, PRM_SYS_CONFIG_1, NULL, tmp, false);
+	if (ret < 0) {
+		dev_err(&hdev->dev, "failed PRM_SYS_CONFIG_1 (%d)\n", ret);
+		goto exit;
+	}
 
-	devInfo.x_active_len_mm =
-		(devInfo.pitch_x * (devInfo.sen_line_num_x - 1)) / 10;
-	devInfo.y_active_len_mm =
-		(devInfo.pitch_y * (devInfo.sen_line_num_y - 1)) / 10;
+	ret = T4_read_write_register(hdev, T4_PRM_FEED_CONFIG_1,
+					NULL, T4_I2C_ABS, false);
+	if (ret < 0) {
+		dev_err(&hdev->dev, "failed T4_PRM_FEED_CONFIG_1 (%d)\n", ret);
+		goto exit;
+	}
 
-	devInfo.x_max =
-		(devInfo.resolution << 2) * (devInfo.sen_line_num_x - 1);
-	devInfo.y_max =
-		(devInfo.resolution << 2) * (devInfo.sen_line_num_y - 1);
+	ret = T4_read_write_register(hdev, T4_PRM_FEED_CONFIG_4, NULL,
+				T4_FEEDCFG4_ADVANCED_ABS_ENABLE, false);
+	if (ret < 0) {
+		dev_err(&hdev->dev, "failed T4_PRM_FEED_CONFIG_4 (%d)\n", ret);
+		goto exit;
+	}
+	pri_data->max_fingers = 5;
+	pri_data->has_sp = 0;
+exit:
+	return ret;
+}
+
+static int alps_input_configured(struct hid_device *hdev, struct hid_input *hi)
+{
+	struct alps_dev *data = hid_get_drvdata(hdev);
+	struct input_dev *input = hi->input, *input2;
+	int ret;
+	int res_x, res_y, i;
+
+	data->input = input;
+
+	hid_dbg(hdev, "Opening low level driver\n");
+	ret = hid_hw_open(hdev);
+	if (ret)
+		return ret;
+
+	/* Allow incoming hid reports */
+	hid_device_io_start(hdev);
+	if (data->dev_type == T4)
+		ret = T4_init(hdev, data);
+	else
+		ret = u1_init(hdev, data);
+
+	if (ret)
+		goto exit;
 
 	__set_bit(EV_ABS, input->evbit);
-	input_set_abs_params(input, ABS_MT_POSITION_X, 1, devInfo.x_max, 0, 0);
-	input_set_abs_params(input, ABS_MT_POSITION_Y, 1, devInfo.y_max, 0, 0);
+	input_set_abs_params(input, ABS_MT_POSITION_X,
+						data->x_min, data->x_max, 0, 0);
+	input_set_abs_params(input, ABS_MT_POSITION_Y,
+						data->y_min, data->y_max, 0, 0);
 
-	if (devInfo.x_active_len_mm && devInfo.y_active_len_mm) {
-		res_x = (devInfo.x_max - 1) / devInfo.x_active_len_mm;
-		res_y = (devInfo.y_max - 1) / devInfo.y_active_len_mm;
+	if (data->x_active_len_mm && data->y_active_len_mm) {
+		res_x = (data->x_max - 1) / data->x_active_len_mm;
+		res_y = (data->y_max - 1) / data->y_active_len_mm;
 
 		input_abs_set_res(input, ABS_MT_POSITION_X, res_x);
 		input_abs_set_res(input, ABS_MT_POSITION_Y, res_y);
@@ -364,49 +677,25 @@ static int alps_input_configured(struct hid_device *hdev, struct hid_input *hi)
 
 	input_set_abs_params(input, ABS_MT_PRESSURE, 0, 64, 0, 0);
 
-	input_mt_init_slots(input, MAX_TOUCHES, INPUT_MT_POINTER);
+	input_mt_init_slots(input, data->max_fingers, INPUT_MT_POINTER);
 
 	__set_bit(EV_KEY, input->evbit);
-	if ((devInfo.btn_info & 0x0F) == (devInfo.btn_info & 0xF0) >> 4) {
-		devInfo.btn_cnt = (devInfo.btn_info & 0x0F);
-	} else {
-		/* Button pad */
-		devInfo.btn_cnt = 1;
+
+	if (data->btn_cnt == 1)
 		__set_bit(INPUT_PROP_BUTTONPAD, input->propbit);
-	}
 
-	for (i = 0; i < devInfo.btn_cnt; i++)
+	for (i = 0; i < data->btn_cnt; i++)
 		__set_bit(BTN_LEFT + i, input->keybit);
 
-
 	/* Stick device initialization */
-	if (devInfo.dev_type & U1_DEVTYPE_SP_SUPPORT) {
-
+	if (data->has_sp) {
 		input2 = input_allocate_device();
 		if (!input2) {
-			ret = -ENOMEM;
-			goto exit;
-		}
-
-		data->input2 = input2;
-
-		devInfo.dev_ctrl |= U1_SP_ABS_MODE;
-		ret = u1_read_write_register(hdev, ADDRESS_U1_DEV_CTRL_1,
-			NULL, devInfo.dev_ctrl, false);
-		if (ret < 0) {
-			dev_err(&hdev->dev, "failed SP mode (%d)\n", ret);
-			input_free_device(input2);
-			goto exit;
-		}
-
-		ret = u1_read_write_register(hdev, ADDRESS_U1_SP_BTN,
-			&devInfo.sp_btn_info, 0, true);
-		if (ret < 0) {
-			dev_err(&hdev->dev, "failed U1_SP_BTN (%d)\n", ret);
 			input_free_device(input2);
 			goto exit;
 		}
 
+		data->input2 = input2;
 		input2->phys = input->phys;
 		input2->name = "DualPoint Stick";
 		input2->id.bustype = BUS_I2C;
@@ -416,8 +705,8 @@ static int alps_input_configured(struct hid_device *hdev, struct hid_input *hi)
 		input2->dev.parent = input->dev.parent;
 
 		__set_bit(EV_KEY, input2->evbit);
-		devInfo.sp_btn_cnt = (devInfo.sp_btn_info & 0x0F);
-		for (i = 0; i < devInfo.sp_btn_cnt; i++)
+		data->sp_btn_cnt = (data->sp_btn_info & 0x0F);
+		for (i = 0; i < data->sp_btn_cnt; i++)
 			__set_bit(BTN_LEFT + i, input2->keybit);
 
 		__set_bit(EV_REL, input2->evbit);
@@ -426,8 +715,7 @@ static int alps_input_configured(struct hid_device *hdev, struct hid_input *hi)
 		__set_bit(INPUT_PROP_POINTER, input2->propbit);
 		__set_bit(INPUT_PROP_POINTING_STICK, input2->propbit);
 
-		ret = input_register_device(data->input2);
-		if (ret) {
+		if (input_register_device(data->input2)) {
 			input_free_device(input2);
 			goto exit;
 		}
@@ -448,10 +736,9 @@ static int alps_input_mapping(struct hid_device *hdev,
 
 static int alps_probe(struct hid_device *hdev, const struct hid_device_id *id)
 {
-	struct u1_dev *data = NULL;
+	struct alps_dev *data = NULL;
 	int ret;
-
-	data = devm_kzalloc(&hdev->dev, sizeof(struct u1_dev), GFP_KERNEL);
+	data = devm_kzalloc(&hdev->dev, sizeof(struct alps_dev), GFP_KERNEL);
 	if (!data)
 		return -ENOMEM;
 
@@ -466,6 +753,17 @@ static int alps_probe(struct hid_device *hdev, const struct hid_device_id *id)
 		return ret;
 	}
 
+	switch (hdev->product) {
+	case HID_DEVICE_ID_ALPS_T4_BTNLESS:
+		data->dev_type = T4;
+		break;
+	case HID_DEVICE_ID_ALPS_U1_DUAL:
+		data->dev_type = U1;
+		break;
+	default:
+		data->dev_type = UNKNOWN;
+	}
+
 	ret = hid_hw_start(hdev, HID_CONNECT_DEFAULT);
 	if (ret) {
 		hid_err(hdev, "hw start failed\n");
@@ -483,6 +781,8 @@ static void alps_remove(struct hid_device *hdev)
 static const struct hid_device_id alps_id[] = {
 	{ HID_DEVICE(HID_BUS_ANY, HID_GROUP_ANY,
 		USB_VENDOR_ID_ALPS_JP, HID_DEVICE_ID_ALPS_U1_DUAL) },
+	{ HID_DEVICE(HID_BUS_ANY, HID_GROUP_ANY,
+		USB_VENDOR_ID_ALPS_JP, HID_DEVICE_ID_ALPS_T4_BTNLESS) },
 	{ }
 };
 MODULE_DEVICE_TABLE(hid, alps_id);
diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c
index 3ceb4a2..f315192 100644
--- a/drivers/hid/hid-core.c
+++ b/drivers/hid/hid-core.c
@@ -1769,7 +1769,8 @@ static const struct hid_device_id hid_have_special_driver[] = {
 	{ HID_USB_DEVICE(USB_VENDOR_ID_A4TECH, USB_DEVICE_ID_A4TECH_RP_649) },
 	{ HID_USB_DEVICE(USB_VENDOR_ID_ACRUX, 0x0802) },
 	{ HID_USB_DEVICE(USB_VENDOR_ID_ACRUX, 0xf705) },
-	{ HID_DEVICE(HID_BUS_ANY, HID_GROUP_ANY, USB_VENDOR_ID_ALPS_JP, HID_DEVICE_ID_ALPS_U1_DUAL) },
+	{ HID_I2C_DEVICE(USB_VENDOR_ID_ALPS_JP, HID_DEVICE_ID_ALPS_U1_DUAL) },
+	{ HID_I2C_DEVICE(USB_VENDOR_ID_ALPS_JP, HID_DEVICE_ID_ALPS_T4_BTNLESS) },
 	{ HID_USB_DEVICE(USB_VENDOR_ID_APPLE, USB_DEVICE_ID_APPLE_MIGHTYMOUSE) },
 	{ HID_BLUETOOTH_DEVICE(USB_VENDOR_ID_APPLE, USB_DEVICE_ID_APPLE_MAGICMOUSE) },
 	{ HID_BLUETOOTH_DEVICE(USB_VENDOR_ID_APPLE, USB_DEVICE_ID_APPLE_MAGICTRACKPAD) },
diff --git a/drivers/hid/hid-ids.h b/drivers/hid/hid-ids.h
index 0e2e7c5..9239543 100644
--- a/drivers/hid/hid-ids.h
+++ b/drivers/hid/hid-ids.h
@@ -75,6 +75,7 @@
 
 #define USB_VENDOR_ID_ALPS_JP		0x044E
 #define HID_DEVICE_ID_ALPS_U1_DUAL	0x120B
+#define HID_DEVICE_ID_ALPS_T4_BTNLESS	0x120C
 
 #define USB_VENDOR_ID_AMI		0x046b
 #define USB_DEVICE_ID_AMI_VIRT_KEYBOARD_AND_MOUSE	0xff10
-- 
2.9.3