ENGR00120162 Add calibration support to touchscreen driver

Add touchscreen calibration support and the BTN_TOUCH.
The calibration algorithm is from Carlos E. Vidales.
and the calibration data is passed to driver by module param.
This driver passes test on ubuntu and android.

Signed-off-by: Xinyu Chen <xinyu.chen@freescale.com>
Signed-off-by: Alejandro Gonzalez <alex.gonzalez@digi.com>

1 files changed, 94 insertions, 23 deletions

diff --git a/drivers/input/touchscreen/mxc_ts.c b/drivers/input/touchscreen/mxc_ts.c
index d60cd51a535e..02b34aceac47 100644
--- a/drivers/input/touchscreen/mxc_ts.c
+++ b/drivers/input/touchscreen/mxc_ts.c
@@ -1,20 +1,27 @@
 /*
- * Copyright 2007-2009 Freescale Semiconductor, Inc. All Rights Reserved.
- */
-
-/*
- * The code contained herein is licensed under the GNU General Public
- * License. You may obtain a copy of the GNU General Public License
- * Version 2 or later at the following locations:
+ * Freescale touchscreen driver
+ *
+ * Copyright (C) 2007-2010 Freescale Semiconductor, Inc. All Rights Reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
  *
- * http://www.opensource.org/licenses/gpl-license.html
- * http://www.gnu.org/copyleft/gpl.html
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
  */
 
 /*!
  * @file mxc_ts.c
  *
- * @brief Driver for the Freescale Semiconductor MXC touchscreen.
+ * @brief Driver for the Freescale Semiconductor MXC touchscreen with calibration support.
  *
  * The touchscreen driver is designed as a standard input driver which is a
  * wrapper over low level PMIC driver. Most of the hardware configuration and
@@ -35,20 +42,33 @@
 #include <linux/freezer.h>
 #include <linux/pmic_external.h>
 #include <linux/pmic_adc.h>
+#include <linux/kthread.h>
 
 #define MXC_TS_NAME	"mxc_ts"
 
-static struct input_dev *mxc_inputdev = NULL;
-static u32 input_ts_installed;
+static struct input_dev *mxc_inputdev;
+static struct task_struct *tstask;
+/**
+ * calibration array refers to
+ * (delta_x[0], delta_x[1], delta_x[2], delta_y[0], delta_y[1], delta_y[2], delta).
+ * Which generated by calibration service.
+ * In this driver when we got touch pointer (x', y') from PMIC ADC,
+ * we calculate the display pointer (x,y) by:
+ * x = (delta_x[0] * x' + delta_x[1] * y' + delta_x[2]) / delta;
+ * y = (delta_y[0] * x' + delta_y[1] * y' + delta_y[2]) / delta;
+ */
+static int calibration[7];
+module_param_array(calibration, int, NULL, S_IRUGO | S_IWUSR);
 
 static int ts_thread(void *arg)
 {
 	t_touch_screen ts_sample;
 	s32 wait = 0, wait2 = 0;
 
-	daemonize("mxc_ts");
-	while (input_ts_installed) {
-		try_to_freeze();
+	do {
+		int x, y;
+		static int last_x = -1, last_y = -1, last_press = -1;
+
 		memset(&ts_sample, 0, sizeof(t_touch_screen));
 		
 		/* After 2 consecutive samples with the pen up, enable irq waiting */
@@ -58,15 +78,59 @@ static int ts_thread(void *arg)
 		if (!(ts_sample.contact_resistance || wait))
 			continue;
 
-		input_report_abs(mxc_inputdev, ABS_X, ts_sample.x_position);
-		input_report_abs(mxc_inputdev, ABS_Y, ts_sample.y_position);
+		if (ts_sample.x_position == 0 && ts_sample.y_position == 0 &&
+			ts_sample.contact_resistance == 0) {
+			x = last_x;
+			y = last_y;
+		} else if (calibration[6] == 0) {
+			x = ts_sample.x_position;
+			y = ts_sample.y_position;
+		} else {
+			x = calibration[0] * (int)ts_sample.x_position +
+				calibration[1] * (int)ts_sample.y_position +
+				calibration[2];
+			x /= calibration[6];
+			if (x < 0)
+				x = 0;
+			y = calibration[3] * (int)ts_sample.x_position +
+				calibration[4] * (int)ts_sample.y_position +
+				calibration[5];
+			y /= calibration[6];
+			if (y < 0)
+				y = 0;
+		}
+
+		if (x != last_x) {
+			input_report_abs(mxc_inputdev, ABS_X, x);
+			last_x = x;
+		}
+		if (y != last_y) {
+			input_report_abs(mxc_inputdev, ABS_Y, y);
+			last_y = y;
+		}
+
+		/* report pressure */
 		input_report_abs(mxc_inputdev, ABS_PRESSURE,
 				 ts_sample.contact_resistance);
+
+#ifdef CONFIG_MXC_PMIC_MC13892
+		/* workaround for aplite ADC resistance large range value */
+		if (ts_sample.contact_resistance > 22)
+			ts_sample.contact_resistance = 1;
+		else
+			ts_sample.contact_resistance = 0;
+#endif
+		/* report the BTN_TOUCH */
+		if (ts_sample.contact_resistance != last_press)
+			input_event(mxc_inputdev, EV_KEY,
+					BTN_TOUCH, ts_sample.contact_resistance);
+
 		input_sync(mxc_inputdev);
+		last_press = ts_sample.contact_resistance;
 		wait2 = wait;
 		wait = ts_sample.contact_resistance;
 		msleep(20);
-	}
+	} while (!kthread_should_stop());
 
 	return 0;
 }
@@ -81,7 +145,7 @@ static int __init mxc_ts_init(void)
 	mxc_inputdev = input_allocate_device();
 	if (!mxc_inputdev) {
 		printk(KERN_ERR
-		       "mxc_ts_init: not enough memory for input device\n");
+		       "mxc_ts_init: not enough memory\n");
 		return -ENOMEM;
 	}
 
@@ -96,15 +160,22 @@ static int __init mxc_ts_init(void)
 		return retval;
 	}
 
-	input_ts_installed = 1;
-	kernel_thread(ts_thread, NULL, CLONE_VM | CLONE_FS);
+	tstask = kthread_run(ts_thread, NULL, "mxc_ts");
+	if (IS_ERR(tstask)) {
+		printk(KERN_ERR
+			"mxc_ts_init: failed to create kthread");
+		tstask = NULL;
+		return -1;
+	}
 	printk("mxc input touchscreen loaded\n");
 	return 0;
 }
 
 static void __exit mxc_ts_exit(void)
 {
-	input_ts_installed = 0;
+	if (tstask)
+		kthread_stop(tstask);
+
 	input_unregister_device(mxc_inputdev);
 
 	if (mxc_inputdev) {
@@ -116,6 +187,6 @@ static void __exit mxc_ts_exit(void)
 late_initcall(mxc_ts_init);
 module_exit(mxc_ts_exit);
 
-MODULE_DESCRIPTION("MXC input touchscreen driver");
+MODULE_DESCRIPTION("MXC touchscreen driver with calibration");
 MODULE_AUTHOR("Freescale Semiconductor, Inc.");
 MODULE_LICENSE("GPL");