Input: pixcir_i2c_ts - support up to 5 fingers and hardware tracking IDs

Some variants of the Pixcir touch controller support up to 5 simultaneous
fingers and hardware tracking IDs. Prepare the driver for that.
Signed-off-by: Roger Quadros <rogerq@ti.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

drivers/input/touchscreen/pixcir_i2c_ts.c

@@ -27,18 +27,20 @@
 #include <linux/input/pixcir_ts.h>
 #include <linux/gpio.h>
 
-#define PIXCIR_MAX_SLOTS       2
+#define PIXCIR_MAX_SLOTS       5 /* Max fingers supported by driver */
 
 struct pixcir_i2c_ts_data {
 	struct i2c_client *client;
 	struct input_dev *input;
-	const struct pixcir_ts_platform_data *chip;
+	const struct pixcir_ts_platform_data *pdata;
 	bool running;
+	int max_fingers;	/* Max fingers supported in this instance */
 };
 
 struct pixcir_touch {
 	int x;
 	int y;
+	int id;
 };
 
 struct pixcir_report_data {
@@ -49,13 +51,21 @@ struct pixcir_report_data {
 static void pixcir_ts_parse(struct pixcir_i2c_ts_data *tsdata,
 			    struct pixcir_report_data *report)
 {
-	u8 rdbuf[10], wrbuf[1] = { 0 };
+	u8 rdbuf[2 + PIXCIR_MAX_SLOTS * 5];
+	u8 wrbuf[1] = { 0 };
 	u8 *bufptr;
 	u8 touch;
 	int ret, i;
+	int readsize;
+	const struct pixcir_i2c_chip_data *chip = &tsdata->pdata->chip;
 
 	memset(report, 0, sizeof(struct pixcir_report_data));
 
+	i = chip->has_hw_ids ? 1 : 0;
+	readsize = 2 + tsdata->max_fingers * (4 + i);
+	if (readsize > sizeof(rdbuf))
+		readsize = sizeof(rdbuf);
+
 	ret = i2c_master_send(tsdata->client, wrbuf, sizeof(wrbuf));
 	if (ret != sizeof(wrbuf)) {
 		dev_err(&tsdata->client->dev,
@@ -64,7 +74,7 @@ static void pixcir_ts_parse(struct pixcir_i2c_ts_data *tsdata,
 		return;
 	}
 
-	ret = i2c_master_recv(tsdata->client, rdbuf, sizeof(rdbuf));
+	ret = i2c_master_recv(tsdata->client, rdbuf, readsize);
 	if (ret != sizeof(rdbuf)) {
 		dev_err(&tsdata->client->dev,
 			"%s: i2c_master_recv failed(), ret=%d\n",
@@ -73,8 +83,8 @@ static void pixcir_ts_parse(struct pixcir_i2c_ts_data *tsdata,
 	}
 
 	touch = rdbuf[0] & 0x7;
-	if (touch > PIXCIR_MAX_SLOTS)
-		touch = PIXCIR_MAX_SLOTS;
+	if (touch > tsdata->max_fingers)
+		touch = tsdata->max_fingers;
 
 	report->num_touches = touch;
 	bufptr = &rdbuf[2];
@@ -83,7 +93,12 @@ static void pixcir_ts_parse(struct pixcir_i2c_ts_data *tsdata,
 		report->touches[i].x = (bufptr[1] << 8) | bufptr[0];
 		report->touches[i].y = (bufptr[3] << 8) | bufptr[2];
 
-		bufptr = bufptr + 4;
+		if (chip->has_hw_ids) {
+			report->touches[i].id = bufptr[4];
+			bufptr = bufptr + 5;
+		} else {
+			bufptr = bufptr + 4;
+		}
 	}
 }
 
@@ -95,22 +110,35 @@ static void pixcir_ts_report(struct pixcir_i2c_ts_data *ts,
 	struct pixcir_touch *touch;
 	int n, i, slot;
 	struct device *dev = &ts->client->dev;
+	const struct pixcir_i2c_chip_data *chip = &ts->pdata->chip;
 
 	n = report->num_touches;
 	if (n > PIXCIR_MAX_SLOTS)
 		n = PIXCIR_MAX_SLOTS;
 
-	for (i = 0; i < n; i++) {
-		touch = &report->touches[i];
-		pos[i].x = touch->x;
-		pos[i].y = touch->y;
-	}
+	if (!chip->has_hw_ids) {
+		for (i = 0; i < n; i++) {
+			touch = &report->touches[i];
+			pos[i].x = touch->x;
+			pos[i].y = touch->y;
+		}
 
-	input_mt_assign_slots(ts->input, slots, pos, n);
+		input_mt_assign_slots(ts->input, slots, pos, n);
+	}
 
 	for (i = 0; i < n; i++) {
 		touch = &report->touches[i];
-		slot = slots[i];
+
+		if (chip->has_hw_ids) {
+			slot = input_mt_get_slot_by_key(ts->input, touch->id);
+			if (slot < 0) {
+				dev_dbg(dev, "no free slot for id 0x%x\n",
+					touch->id);
+				continue;
+			}
+		} else {
+			slot = slots[i];
+		}
 
 		input_mt_slot(ts->input, slot);
 		input_mt_report_slot_state(ts->input,
@@ -130,7 +158,7 @@ static void pixcir_ts_report(struct pixcir_i2c_ts_data *ts,
 static irqreturn_t pixcir_ts_isr(int irq, void *dev_id)
 {
 	struct pixcir_i2c_ts_data *tsdata = dev_id;
-	const struct pixcir_ts_platform_data *pdata = tsdata->chip;
+	const struct pixcir_ts_platform_data *pdata = tsdata->pdata;
 	struct pixcir_report_data report;
 
 	while (tsdata->running) {
@@ -399,6 +427,11 @@ static int pixcir_i2c_ts_probe(struct i2c_client *client,
 		return -EINVAL;
 	}
 
+	if (!pdata->chip.max_fingers) {
+		dev_err(dev, "Invalid max_fingers in pdata\n");
+		return -EINVAL;
+	}
+
 	tsdata = devm_kzalloc(dev, sizeof(*tsdata), GFP_KERNEL);
 	if (!tsdata)
 		return -ENOMEM;
@@ -411,7 +444,7 @@ static int pixcir_i2c_ts_probe(struct i2c_client *client,
 
 	tsdata->client = client;
 	tsdata->input = input;
-	tsdata->chip = pdata;
+	tsdata->pdata = pdata;
 
 	input->name = client->name;
 	input->id.bustype = BUS_I2C;
@@ -427,7 +460,14 @@ static int pixcir_i2c_ts_probe(struct i2c_client *client,
 	input_set_abs_params(input, ABS_MT_POSITION_X, 0, pdata->x_max, 0, 0);
 	input_set_abs_params(input, ABS_MT_POSITION_Y, 0, pdata->y_max, 0, 0);
 
-	error = input_mt_init_slots(input, PIXCIR_MAX_SLOTS,
+	tsdata->max_fingers = tsdata->pdata->chip.max_fingers;
+	if (tsdata->max_fingers > PIXCIR_MAX_SLOTS) {
+		tsdata->max_fingers = PIXCIR_MAX_SLOTS;
+		dev_info(dev, "Limiting maximum fingers to %d\n",
+			 tsdata->max_fingers);
+	}
+
+	error = input_mt_init_slots(input, tsdata->max_fingers,
 				    INPUT_MT_DIRECT | INPUT_MT_DROP_UNUSED);
 	if (error) {
 		dev_err(dev, "Error initializing Multi-Touch slots\n");

include/linux/input/pixcir_ts.h

@@ -43,10 +43,22 @@ enum pixcir_int_mode {
 #define PIXCIR_INT_ENABLE	(1UL << 3)
 #define PIXCIR_INT_POL_HIGH	(1UL << 2)
 
+/**
+ * struct pixcir_irc_chip_data - chip related data
+ * @max_fingers:	Max number of fingers reported simultaneously by h/w
+ * @has_hw_ids:		Hardware supports finger tracking IDs
+ *
+ */
+struct pixcir_i2c_chip_data {
+	u8 max_fingers;
+	bool has_hw_ids;
+};
+
 struct pixcir_ts_platform_data {
 	int x_max;
 	int y_max;
 	int gpio_attb;		/* GPIO connected to ATTB line */
+	struct pixcir_i2c_chip_data chip;
 };
 
 #endif