Input: atmel_mxt_ts - Support for touchpad variant

This same driver can be used by atmel based touchscreens and touchpads
(buttonpads). Platform data may specify a device is a touchpad
using the is_tp flag.

This will cause the driver to perform some touchpad specific
initializations, such as:
  * register input device name "Atmel maXTouch Touchpad" instead of
  Touchscreen.
  * register BTN_LEFT & BTN_TOOL_* event types.
  * register axis resolution (as a fixed constant, for now)
  * register BUTTONPAD property
  * process GPIO buttons using reportid T19

Input event GPIO mapping is done by the platform data key_map array.

key_map[x] should contain the KEY or BTN code to send when processing
GPIOx from T19. To specify a GPIO as not an input source, populate
with KEY_RESERVED, or 0.
Signed-off-by: NDaniel Kurtz <djkurtz@chromium.org>
Signed-off-by: NBenson Leung <bleung@chromium.org>
Signed-off-by: NNick Dyer <nick.dyer@itdev.co.uk>
Tested-by: NOlof Johansson <olof@lixom.net>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

drivers/input/touchscreen/atmel_mxt_ts.c

@@ -181,6 +181,12 @@
 
 #define MXT_FWRESET_TIME	175	/* msec */
 
+/* MXT_SPT_GPIOPWM_T19 field */
+#define MXT_GPIO0_MASK		0x04
+#define MXT_GPIO1_MASK		0x08
+#define MXT_GPIO2_MASK		0x10
+#define MXT_GPIO3_MASK		0x20
+
 /* Command to unlock bootloader */
 #define MXT_UNLOCK_CMD_MSB	0xaa
 #define MXT_UNLOCK_CMD_LSB	0xdc
@@ -212,6 +218,8 @@
 /* Touchscreen absolute values */
 #define MXT_MAX_AREA		0xff
 
+#define MXT_PIXELS_PER_MM	20
+
 struct mxt_info {
 	u8 family_id;
 	u8 variant_id;
@@ -243,6 +251,8 @@ struct mxt_data {
 	const struct mxt_platform_data *pdata;
 	struct mxt_object *object_table;
 	struct mxt_info info;
+	bool is_tp;
+
 	unsigned int irq;
 	unsigned int max_x;
 	unsigned int max_y;
@@ -251,6 +261,7 @@ struct mxt_data {
 	u8 T6_reportid;
 	u8 T9_reportid_min;
 	u8 T9_reportid_max;
+	u8 T19_reportid;
 };
 
 static bool mxt_object_readable(unsigned int type)
@@ -502,6 +513,21 @@ static int mxt_write_object(struct mxt_data *data,
 	return mxt_write_reg(data->client, reg + offset, val);
 }
 
+static void mxt_input_button(struct mxt_data *data, struct mxt_message *message)
+{
+	struct input_dev *input = data->input_dev;
+	bool button;
+	int i;
+
+	/* Active-low switch */
+	for (i = 0; i < MXT_NUM_GPIO; i++) {
+		if (data->pdata->key_map[i] == KEY_RESERVED)
+			continue;
+		button = !(message->message[0] & MXT_GPIO0_MASK << i);
+		input_report_key(input, data->pdata->key_map[i], button);
+	}
+}
+
 static void mxt_input_touchevent(struct mxt_data *data,
 				      struct mxt_message *message, int id)
 {
@@ -585,6 +611,9 @@ static irqreturn_t mxt_interrupt(int irq, void *dev_id)
 			int id = reportid - data->T9_reportid_min;
 			mxt_input_touchevent(data, &message, id);
 			update_input = true;
+		} else if (message.reportid == data->T19_reportid) {
+			mxt_input_button(data, &message);
+			update_input = true;
 		} else {
 			mxt_dump_message(dev, &message);
 		}
@@ -764,6 +793,9 @@ static int mxt_get_object_table(struct mxt_data *data)
 			data->T9_reportid_min = min_id;
 			data->T9_reportid_max = max_id;
 			break;
+		case MXT_SPT_GPIOPWM_T19:
+			data->T19_reportid = min_id;
+			break;
 		}
 	}
 
@@ -777,7 +809,7 @@ static void mxt_free_object_table(struct mxt_data *data)
 	data->T6_reportid = 0;
 	data->T9_reportid_min = 0;
 	data->T9_reportid_max = 0;
-
+	data->T19_reportid = 0;
 }
 
 static int mxt_initialize(struct mxt_data *data)
@@ -1115,9 +1147,13 @@ static int mxt_probe(struct i2c_client *client,
 		goto err_free_mem;
 	}
 
-	input_dev->name = "Atmel maXTouch Touchscreen";
+	data->is_tp = pdata && pdata->is_tp;
+
+	input_dev->name = (data->is_tp) ? "Atmel maXTouch Touchpad" :
+					  "Atmel maXTouch Touchscreen";
 	snprintf(data->phys, sizeof(data->phys), "i2c-%u-%04x/input0",
 		 client->adapter->nr, client->addr);
+
 	input_dev->phys = data->phys;
 
 	input_dev->id.bustype = BUS_I2C;
@@ -1140,6 +1176,29 @@ static int mxt_probe(struct i2c_client *client,
 	__set_bit(EV_KEY, input_dev->evbit);
 	__set_bit(BTN_TOUCH, input_dev->keybit);
 
+	if (data->is_tp) {
+		int i;
+		__set_bit(INPUT_PROP_POINTER, input_dev->propbit);
+		__set_bit(INPUT_PROP_BUTTONPAD, input_dev->propbit);
+
+		for (i = 0; i < MXT_NUM_GPIO; i++)
+			if (pdata->key_map[i] != KEY_RESERVED)
+				__set_bit(pdata->key_map[i], input_dev->keybit);
+
+		__set_bit(BTN_TOOL_FINGER, input_dev->keybit);
+		__set_bit(BTN_TOOL_DOUBLETAP, input_dev->keybit);
+		__set_bit(BTN_TOOL_TRIPLETAP, input_dev->keybit);
+		__set_bit(BTN_TOOL_QUADTAP, input_dev->keybit);
+		__set_bit(BTN_TOOL_QUINTTAP, input_dev->keybit);
+
+		input_abs_set_res(input_dev, ABS_X, MXT_PIXELS_PER_MM);
+		input_abs_set_res(input_dev, ABS_Y, MXT_PIXELS_PER_MM);
+		input_abs_set_res(input_dev, ABS_MT_POSITION_X,
+				  MXT_PIXELS_PER_MM);
+		input_abs_set_res(input_dev, ABS_MT_POSITION_Y,
+				  MXT_PIXELS_PER_MM);
+	}
+
 	/* For single touch */
 	input_set_abs_params(input_dev, ABS_X,
 			     0, data->max_x, 0, 0);
@@ -1258,6 +1317,7 @@ static SIMPLE_DEV_PM_OPS(mxt_pm_ops, mxt_suspend, mxt_resume);
 static const struct i2c_device_id mxt_id[] = {
 	{ "qt602240_ts", 0 },
 	{ "atmel_mxt_ts", 0 },
+	{ "atmel_mxt_tp", 0 },
 	{ "mXT224", 0 },
 	{ }
 };

include/linux/i2c/atmel_mxt_ts.h

@@ -15,6 +15,9 @@
 
 #include <linux/types.h>
 
+/* For key_map array */
+#define MXT_NUM_GPIO		4
+
 /* Orient */
 #define MXT_NORMAL		0x0
 #define MXT_DIAGONAL		0x1
@@ -39,6 +42,8 @@ struct mxt_platform_data {
 	unsigned int voltage;
 	unsigned char orient;
 	unsigned long irqflags;
+	bool is_tp;
+	const unsigned int key_map[MXT_NUM_GPIO];
 };
 
 #endif /* __LINUX_ATMEL_MXT_TS_H */