[PATCH] Add support for touch screens using the General Touch ST6001S controller.

[Gareth Randall <gareth.randall@xxxxxxxxxx>]

Add support for touch screens using the General Touch ST6001S controller,
as found in the GPEG model AOD22WZ-ST monitor. This controller can output
the ELO 10-byte protocol, but requires different initialisation.

Signed-off-by: Gareth Randall <gareth@xxxxxxxxxxxxxxxxx>
---
 drivers/input/touchscreen/elo.c | 81 ++++++++++++++++++++++++++++++++-
 1 file changed, 80 insertions(+), 1 deletion(-)

diff --git a/drivers/input/touchscreen/elo.c b/drivers/input/touchscreen/elo.c
index 96173232e53f..b233869ffa2a 100644
--- a/drivers/input/touchscreen/elo.c
+++ b/drivers/input/touchscreen/elo.c
@@ -26,6 +26,27 @@ MODULE_AUTHOR("Vojtech Pavlik <vojtech@xxxxxx>");
 MODULE_DESCRIPTION(DRIVER_DESC);
 MODULE_LICENSE("GPL");

+static uint gt_abs_x_min;
+module_param(gt_abs_x_min, uint, 0444);
+MODULE_PARM_DESC(gt_abs_x_min, "abs_x min value in General Touch mode (default: 0)");
+
+static uint gt_abs_x_max = 4095;
+module_param(gt_abs_x_max, uint, 0444);
+MODULE_PARM_DESC(gt_abs_x_max, "abs_x max value in General Touch mode (default: 4095)");
+
+static uint gt_abs_y_min;
+module_param(gt_abs_y_min, uint, 0444);
+MODULE_PARM_DESC(gt_abs_y_min, "abs_y min value in General Touch mode (default: 0)");
+
+static uint gt_abs_y_max = 4095;
+module_param(gt_abs_y_max, uint, 0444);
+MODULE_PARM_DESC(gt_abs_y_max, "abs_y max value in General Touch mode (default: 4095)");
+
+static bool gt_mode_override;
+module_param(gt_mode_override, bool, 0444);
+MODULE_PARM_DESC(gt_mode_override, "force the use of General Touch mode (default: false)");
+
+
 /*
  * Definitions & global arrays.
  */
@@ -44,6 +65,8 @@ MODULE_LICENSE("GPL");
 #define ELO10_ACK_PACKET	'A'
 #define ELI10_ID_PACKET		'I'

+#define ELO_GT_INIT_PACKET	"\001XfE\r"
+
 /*
  * Per-touchscreen data.
  */
@@ -201,6 +224,7 @@ static irqreturn_t elo_interrupt(struct serio *serio,

 	switch (elo->id) {
 	case 0:
+	case 4:
 		elo_process_data_10(elo, data);
 		break;

@@ -255,6 +279,50 @@ static int elo_command_10(struct elo *elo, unsigned char *packet)
 	return rc;
 }

+/*
+ * Initialise the General Touch ST6001S controller.
+ */
+static int elo_command_10_gt(struct elo *elo)
+{
+	int rc = -1;
+	int i;
+	unsigned char *packet = ELO_GT_INIT_PACKET;
+
+	mutex_lock(&elo->cmd_mutex);
+
+	serio_pause_rx(elo->serio);
+	init_completion(&elo->cmd_done);
+	serio_continue_rx(elo->serio);
+
+	for (i = 0; i < (int)strlen(packet); i++) {
+		if (serio_write(elo->serio, packet[i]))
+			goto out;
+	}
+
+	wait_for_completion_timeout(&elo->cmd_done, HZ);
+	rc = 0;
+
+ out:
+	mutex_unlock(&elo->cmd_mutex);
+	return rc;
+}
+
+static int elo_setup_10_gt(struct elo *elo)
+{
+	struct input_dev *dev = elo->dev;
+
+	if (elo_command_10_gt(elo))
+		return -EIO;
+
+	input_set_abs_params(dev, ABS_X, gt_abs_x_min, gt_abs_x_max, 0, 0);
+	input_set_abs_params(dev, ABS_Y, gt_abs_y_min, gt_abs_y_max, 0, 0);
+
+	dev_info(&elo->serio->dev,
+		 "GeneralTouch ST6001S touchscreen");
+
+	return 0;
+}
+
 static int elo_setup_10(struct elo *elo)
 {
 	static const char *elo_types[] = { "Accu", "Dura", "Intelli", "Carroll" };
@@ -273,7 +341,7 @@ static int elo_setup_10(struct elo *elo)

 	dev_info(&elo->serio->dev,
 		 "%sTouch touchscreen, fw: %02x.%02x, features: 0x%02x, controller: 0x%02x\n",
-		 elo_types[(packet[1] -'0') & 0x03],
+		 elo_types[(packet[1] - '0') & 0x03],
 		 packet[5], packet[4], packet[3], packet[7]);

 	return 0;
@@ -332,12 +400,16 @@ static int elo_connect(struct serio *serio, struct serio_driver *drv)

 	input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
 	input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
+	__set_bit(INPUT_PROP_DIRECT, input_dev->propbit);

 	serio_set_drvdata(serio, elo);
 	err = serio_open(serio, drv);
 	if (err)
 		goto fail2;

+	if (gt_mode_override)
+		elo->id = 4;
+
 	switch (elo->id) {

 	case 0: /* 10-byte protocol */
@@ -361,6 +433,13 @@ static int elo_connect(struct serio *serio, struct serio_driver *drv)
 		input_set_abs_params(input_dev, ABS_X, 0, 255, 0, 0);
 		input_set_abs_params(input_dev, ABS_Y, 0, 255, 0, 0);
 		break;
+
+	case 4: /* 10-byte protocol with General Touch initialisation */
+		if (elo_setup_10_gt(elo)) {
+			err = -EIO;
+			goto fail3;
+		}
+		break;
 	}

 	err = input_register_device(elo->dev);
--
2.27.0