Input: atmel_mxt_ts - implement support for T100 touch object

Add support for the new T100 object which replaces the previous T9
multitouch touchscreen object in recent maXTouch devices. T100 provides
improved reporting with selectable auxiliary information, and a type field
for hover/stylus/glove reporting.

The hovering finger support was based on Chung-Yih's work in the ChromiumOS
downstream kernel:

https://chromium-review.googlesource.com/#/c/219280/Signed-off-by: Nick Dyer <nick.dyer@itdev.co.uk>
Acked-by: Yufeng Shen <miletus@chromium.org>
[javier: Factor out T9 and T100 init functions and rework hover support]
Signed-off-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

drivers/input/touchscreen/atmel_mxt_ts.c

@@ -25,6 +25,7 @@
 #include <linux/interrupt.h>
 #include <linux/of.h>
 #include <linux/slab.h>
+#include <asm/unaligned.h>
 
 /* Version */
 #define MXT_VER_20		20
@@ -79,6 +80,7 @@
 #define MXT_SPT_DIGITIZER_T43		43
 #define MXT_SPT_MESSAGECOUNT_T44	44
 #define MXT_SPT_CTECONFIG_T46		46
+#define MXT_TOUCH_MULTITOUCHSCREEN_T100 100
 
 /* MXT_GEN_MESSAGE_T5 object */
 #define MXT_RPTID_NOMSG		0xff
@@ -185,6 +187,36 @@ struct t9_range {
 #define MXT_RESET_VALUE		0x01
 #define MXT_BACKUP_VALUE	0x55
 
+/* T100 Multiple Touch Touchscreen */
+#define MXT_T100_CTRL		0
+#define MXT_T100_CFG1		1
+#define MXT_T100_TCHAUX		3
+#define MXT_T100_XRANGE		13
+#define MXT_T100_YRANGE		24
+
+#define MXT_T100_CFG_SWITCHXY	BIT(5)
+
+#define MXT_T100_TCHAUX_VECT	BIT(0)
+#define MXT_T100_TCHAUX_AMPL	BIT(1)
+#define MXT_T100_TCHAUX_AREA	BIT(2)
+
+#define MXT_T100_DETECT		BIT(7)
+#define MXT_T100_TYPE_MASK	0x70
+
+enum t100_type {
+	MXT_T100_TYPE_FINGER		= 1,
+	MXT_T100_TYPE_PASSIVE_STYLUS	= 2,
+	MXT_T100_TYPE_HOVERING_FINGER	= 4,
+	MXT_T100_TYPE_GLOVE		= 5,
+	MXT_T100_TYPE_LARGE_TOUCH	= 6,
+};
+
+#define MXT_DISTANCE_ACTIVE_TOUCH	0
+#define MXT_DISTANCE_HOVERING		1
+
+#define MXT_TOUCH_MAJOR_DEFAULT		1
+#define MXT_PRESSURE_DEFAULT		1
+
 /* Delay times */
 #define MXT_BACKUP_TIME		50	/* msec */
 #define MXT_RESET_TIME		200	/* msec */
@@ -244,6 +276,9 @@ struct mxt_data {
 	unsigned int max_y;
 	bool in_bootloader;
 	u16 mem_size;
+	u8 t100_aux_ampl;
+	u8 t100_aux_area;
+	u8 t100_aux_vect;
 	u8 max_reportid;
 	u32 config_crc;
 	u32 info_crc;
@@ -253,6 +288,7 @@ struct mxt_data {
 	bool update_input;
 	u8 last_message_count;
 	u8 num_touchids;
+	u8 multitouch;
 
 	/* Cached parameters from object table */
 	u16 T5_address;
@@ -264,6 +300,8 @@ struct mxt_data {
 	u8 T9_reportid_max;
 	u8 T19_reportid;
 	u16 T44_address;
+	u8 T100_reportid_min;
+	u8 T100_reportid_max;
 
 	/* for fw update in bootloader */
 	struct completion bl_completion;
@@ -771,6 +809,114 @@ static void mxt_proc_t9_message(struct mxt_data *data, u8 *message)
 	data->update_input = true;
 }
 
+static void mxt_proc_t100_message(struct mxt_data *data, u8 *message)
+{
+	struct device *dev = &data->client->dev;
+	struct input_dev *input_dev = data->input_dev;
+	int id;
+	u8 status;
+	u8 type = 0;
+	u16 x;
+	u16 y;
+	int distance = 0;
+	int tool = 0;
+	u8 major = 0;
+	u8 pressure = 0;
+	u8 orientation = 0;
+
+	id = message[0] - data->T100_reportid_min - 2;
+
+	/* ignore SCRSTATUS events */
+	if (id < 0)
+		return;
+
+	status = message[1];
+	x = get_unaligned_le16(&message[2]);
+	y = get_unaligned_le16(&message[4]);
+
+	if (status & MXT_T100_DETECT) {
+		type = (status & MXT_T100_TYPE_MASK) >> 4;
+
+		switch (type) {
+		case MXT_T100_TYPE_HOVERING_FINGER:
+			tool = MT_TOOL_FINGER;
+			distance = MXT_DISTANCE_HOVERING;
+
+			if (data->t100_aux_vect)
+				orientation = message[data->t100_aux_vect];
+
+			break;
+
+		case MXT_T100_TYPE_FINGER:
+		case MXT_T100_TYPE_GLOVE:
+			tool = MT_TOOL_FINGER;
+			distance = MXT_DISTANCE_ACTIVE_TOUCH;
+
+			if (data->t100_aux_area)
+				major = message[data->t100_aux_area];
+
+			if (data->t100_aux_ampl)
+				pressure = message[data->t100_aux_ampl];
+
+			if (data->t100_aux_vect)
+				orientation = message[data->t100_aux_vect];
+
+			break;
+
+		case MXT_T100_TYPE_PASSIVE_STYLUS:
+			tool = MT_TOOL_PEN;
+
+			/*
+			 * Passive stylus is reported with size zero so
+			 * hardcode.
+			 */
+			major = MXT_TOUCH_MAJOR_DEFAULT;
+
+			if (data->t100_aux_ampl)
+				pressure = message[data->t100_aux_ampl];
+
+			break;
+
+		case MXT_T100_TYPE_LARGE_TOUCH:
+			/* Ignore suppressed touch */
+			break;
+
+		default:
+			dev_dbg(dev, "Unexpected T100 type\n");
+			return;
+		}
+	}
+
+	/*
+	 * Values reported should be non-zero if tool is touching the
+	 * device
+	 */
+	if (!pressure && type != MXT_T100_TYPE_HOVERING_FINGER)
+		pressure = MXT_PRESSURE_DEFAULT;
+
+	input_mt_slot(input_dev, id);
+
+	if (status & MXT_T100_DETECT) {
+		dev_dbg(dev, "[%u] type:%u x:%u y:%u a:%02X p:%02X v:%02X\n",
+			id, type, x, y, major, pressure, orientation);
+
+		input_mt_report_slot_state(input_dev, tool, 1);
+		input_report_abs(input_dev, ABS_MT_POSITION_X, x);
+		input_report_abs(input_dev, ABS_MT_POSITION_Y, y);
+		input_report_abs(input_dev, ABS_MT_TOUCH_MAJOR, major);
+		input_report_abs(input_dev, ABS_MT_PRESSURE, pressure);
+		input_report_abs(input_dev, ABS_MT_DISTANCE, distance);
+		input_report_abs(input_dev, ABS_MT_ORIENTATION, orientation);
+	} else {
+		dev_dbg(dev, "[%u] release\n", id);
+
+		/* close out slot */
+		input_mt_report_slot_state(input_dev, 0, 0);
+	}
+
+	data->update_input = true;
+}
+
 static int mxt_proc_message(struct mxt_data *data, u8 *message)
 {
 	u8 report_id = message[0];
@@ -786,9 +932,12 @@ static int mxt_proc_message(struct mxt_data *data, u8 *message)
 		 * is not yet registered.
 		 */
 		mxt_dump_message(data, message);
-	} else if (report_id >= data->T9_reportid_min
-	    && report_id <= data->T9_reportid_max) {
+	} else if (report_id >= data->T9_reportid_min &&
+		   report_id <= data->T9_reportid_max) {
 		mxt_proc_t9_message(data, message);
+	} else if (report_id >= data->T100_reportid_min &&
+		   report_id <= data->T100_reportid_max) {
+		mxt_proc_t100_message(data, message);
 	} else if (report_id == data->T19_reportid) {
 		mxt_input_button(data, message);
 		data->update_input = true;
@@ -1411,6 +1560,8 @@ static void mxt_free_object_table(struct mxt_data *data)
 	data->T9_reportid_max = 0;
 	data->T19_reportid = 0;
 	data->T44_address = 0;
+	data->T100_reportid_min = 0;
+	data->T100_reportid_max = 0;
 	data->max_reportid = 0;
 }
 
@@ -1487,6 +1638,7 @@ static int mxt_get_object_table(struct mxt_data *data)
 			data->T7_address = object->start_address;
 			break;
 		case MXT_TOUCH_MULTI_T9:
+			data->multitouch = MXT_TOUCH_MULTI_T9;
 			data->T9_reportid_min = min_id;
 			data->T9_reportid_max = max_id;
 			data->num_touchids = object->num_report_ids
@@ -1498,6 +1650,13 @@ static int mxt_get_object_table(struct mxt_data *data)
 		case MXT_SPT_GPIOPWM_T19:
 			data->T19_reportid = min_id;
 			break;
+		case MXT_TOUCH_MULTITOUCHSCREEN_T100:
+			data->multitouch = MXT_TOUCH_MULTITOUCHSCREEN_T100;
+			data->T100_reportid_min = min_id;
+			data->T100_reportid_max = max_id;
+			/* first two report IDs reserved */
+			data->num_touchids = object->num_report_ids - 2;
+			break;
 		}
 
 		end_address = object->start_address
@@ -1582,10 +1741,88 @@ static int mxt_read_t9_resolution(struct mxt_data *data)
 	return 0;
 }
 
+static int mxt_read_t100_config(struct mxt_data *data)
+{
+	struct i2c_client *client = data->client;
+	int error;
+	struct mxt_object *object;
+	u16 range_x, range_y;
+	u8 cfg, tchaux;
+	u8 aux;
+
+	object = mxt_get_object(data, MXT_TOUCH_MULTITOUCHSCREEN_T100);
+	if (!object)
+		return -EINVAL;
+
+	error = __mxt_read_reg(client,
+			       object->start_address + MXT_T100_XRANGE,
+			       sizeof(range_x), &range_x);
+	if (error)
+		return error;
+
+	le16_to_cpus(&range_x);
+
+	error = __mxt_read_reg(client,
+			       object->start_address + MXT_T100_YRANGE,
+			       sizeof(range_y), &range_y);
+	if (error)
+		return error;
+
+	le16_to_cpus(&range_y);
+
+	error =  __mxt_read_reg(client,
+				object->start_address + MXT_T100_CFG1,
+				1, &cfg);
+	if (error)
+		return error;
+
+	error =  __mxt_read_reg(client,
+				object->start_address + MXT_T100_TCHAUX,
+				1, &tchaux);
+	if (error)
+		return error;
+
+	/* Handle default values */
+	if (range_x == 0)
+		range_x = 1023;
+
+	if (range_y == 0)
+		range_y = 1023;
+
+	if (cfg & MXT_T100_CFG_SWITCHXY) {
+		data->max_x = range_y;
+		data->max_y = range_x;
+	} else {
+		data->max_x = range_x;
+		data->max_y = range_y;
+	}
+
+	/* allocate aux bytes */
+	aux = 6;
+
+	if (tchaux & MXT_T100_TCHAUX_VECT)
+		data->t100_aux_vect = aux++;
+
+	if (tchaux & MXT_T100_TCHAUX_AMPL)
+		data->t100_aux_ampl = aux++;
+
+	if (tchaux & MXT_T100_TCHAUX_AREA)
+		data->t100_aux_area = aux++;
+
+	dev_dbg(&client->dev,
+		"T100 aux mappings vect:%u ampl:%u area:%u\n",
+		data->t100_aux_vect, data->t100_aux_ampl, data->t100_aux_area);
+
+	dev_info(&client->dev,
+		 "T100 Touchscreen size X%uY%u\n", data->max_x, data->max_y);
+
+	return 0;
+}
+
 static int mxt_input_open(struct input_dev *dev);
 static void mxt_input_close(struct input_dev *dev);
 
-static int mxt_initialize_t9_input_device(struct mxt_data *data)
+static int mxt_initialize_input_device(struct mxt_data *data)
 {
 	struct device *dev = &data->client->dev;
 	const struct mxt_platform_data *pdata = data->pdata;
@@ -1595,9 +1832,25 @@ static int mxt_initialize_t9_input_device(struct mxt_data *data)
 	unsigned int mt_flags = 0;
 	int i;
 
+	switch (data->multitouch) {
+	case MXT_TOUCH_MULTI_T9:
+		num_mt_slots = data->T9_reportid_max - data->T9_reportid_min + 1;
 		error = mxt_read_t9_resolution(data);
 		if (error)
 			dev_warn(dev, "Failed to initialize T9 resolution\n");
+		break;
+
+	case MXT_TOUCH_MULTITOUCHSCREEN_T100:
+		num_mt_slots = data->num_touchids;
+		error = mxt_read_t100_config(data);
+		if (error)
+			dev_warn(dev, "Failed to read T100 config\n");
+		break;
+
+	default:
+		dev_err(dev, "Invalid multitouch object\n");
+		return -EINVAL;
+	}
 
 	input_dev = input_allocate_device();
 	if (!input_dev) {
@@ -1612,9 +1865,7 @@ static int mxt_initialize_t9_input_device(struct mxt_data *data)
 	input_dev->open = mxt_input_open;
 	input_dev->close = mxt_input_close;
 
-	__set_bit(EV_ABS, input_dev->evbit);
-	__set_bit(EV_KEY, input_dev->evbit);
-	__set_bit(BTN_TOUCH, input_dev->keybit);
+	input_set_capability(input_dev, EV_KEY, BTN_TOUCH);
 
 	if (pdata->t19_num_keys) {
 		__set_bit(INPUT_PROP_BUTTONPAD, input_dev->propbit);
@@ -1637,29 +1888,67 @@ static int mxt_initialize_t9_input_device(struct mxt_data *data)
 	}
 
 	/* For single touch */
-	input_set_abs_params(input_dev, ABS_X,
-			     0, data->max_x, 0, 0);
-	input_set_abs_params(input_dev, ABS_Y,
-			     0, data->max_y, 0, 0);
-	input_set_abs_params(input_dev, ABS_PRESSURE,
-			     0, 255, 0, 0);
+	input_set_abs_params(input_dev, ABS_X, 0, data->max_x, 0, 0);
+	input_set_abs_params(input_dev, ABS_Y, 0, data->max_y, 0, 0);
+
+	if (data->multitouch == MXT_TOUCH_MULTI_T9 ||
+	    (data->multitouch == MXT_TOUCH_MULTITOUCHSCREEN_T100 &&
+	     data->t100_aux_ampl)) {
+		input_set_abs_params(input_dev, ABS_PRESSURE, 0, 255, 0, 0);
+	}
 
 	/* For multi touch */
-	num_mt_slots = data->T9_reportid_max - data->T9_reportid_min + 1;
 	error = input_mt_init_slots(input_dev, num_mt_slots, mt_flags);
 	if (error) {
 		dev_err(dev, "Error %d initialising slots\n", error);
 		goto err_free_mem;
 	}
 
-	input_set_abs_params(input_dev, ABS_MT_TOUCH_MAJOR,
-			     0, MXT_MAX_AREA, 0, 0);
+	if (data->multitouch == MXT_TOUCH_MULTITOUCHSCREEN_T100) {
+		input_set_abs_params(input_dev, ABS_MT_TOOL_TYPE,
+				     0, MT_TOOL_MAX, 0, 0);
+		input_set_abs_params(input_dev, ABS_MT_DISTANCE,
+				     MXT_DISTANCE_ACTIVE_TOUCH,
+				     MXT_DISTANCE_HOVERING,
+				     0, 0);
+	}
+
 	input_set_abs_params(input_dev, ABS_MT_POSITION_X,
 			     0, data->max_x, 0, 0);
 	input_set_abs_params(input_dev, ABS_MT_POSITION_Y,
 			     0, data->max_y, 0, 0);
+
+	if (data->multitouch == MXT_TOUCH_MULTI_T9 ||
+	    (data->multitouch == MXT_TOUCH_MULTITOUCHSCREEN_T100 &&
+	     data->t100_aux_area)) {
+		input_set_abs_params(input_dev, ABS_MT_TOUCH_MAJOR,
+				     0, MXT_MAX_AREA, 0, 0);
+	}
+
+	if (data->multitouch == MXT_TOUCH_MULTI_T9 ||
+	    (data->multitouch == MXT_TOUCH_MULTITOUCHSCREEN_T100 &&
+	     data->t100_aux_ampl)) {
 		input_set_abs_params(input_dev, ABS_MT_PRESSURE,
 				     0, 255, 0, 0);
+	}
+
+	if (data->multitouch == MXT_TOUCH_MULTITOUCHSCREEN_T100 &&
+	    data->t100_aux_vect) {
+		input_set_abs_params(input_dev, ABS_MT_ORIENTATION,
+				     0, 255, 0, 0);
+	}
+
+	if (data->multitouch == MXT_TOUCH_MULTITOUCHSCREEN_T100 &&
+	    data->t100_aux_ampl) {
+		input_set_abs_params(input_dev, ABS_MT_PRESSURE,
+				     0, 255, 0, 0);
+	}
+
+	if (data->multitouch == MXT_TOUCH_MULTITOUCHSCREEN_T100 &&
+	    data->t100_aux_vect) {
+		input_set_abs_params(input_dev, ABS_MT_ORIENTATION,
+				     0, 255, 0, 0);
+	}
 
 	input_set_drvdata(input_dev, data);
 
@@ -1765,9 +2054,13 @@ static int mxt_configure_objects(struct mxt_data *data,
 			dev_warn(dev, "Error %d updating config\n", error);
 	}
 
-	error = mxt_initialize_t9_input_device(data);
+	if (data->multitouch) {
+		error = mxt_initialize_input_device(data);
 		if (error)
 			return error;
+	} else {
+		dev_warn(dev, "No touch object detected\n");
+	}
 
 	dev_info(dev,
 		 "Family: %u Variant: %u Firmware V%u.%u.%02X Objects: %u\n",
@@ -2044,15 +2337,13 @@ static const struct attribute_group mxt_attr_group = {
 static void mxt_start(struct mxt_data *data)
 {
 	/* Touch enable */
-	mxt_write_object(data,
-			MXT_TOUCH_MULTI_T9, MXT_TOUCH_CTRL, 0x83);
+	mxt_write_object(data, data->multitouch, MXT_TOUCH_CTRL, 0x83);
 }
 
 static void mxt_stop(struct mxt_data *data)
 {
 	/* Touch disable */
-	mxt_write_object(data,
-			MXT_TOUCH_MULTI_T9, MXT_TOUCH_CTRL, 0);
+	mxt_write_object(data, data->multitouch, MXT_TOUCH_CTRL, 0);
 }
 
 static int mxt_input_open(struct input_dev *dev)