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/*
* 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.
*
* 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 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
* touchscreen functionality is implemented in the low level PMIC driver. During
* initialization, this driver creates a kernel thread. This thread then calls
* PMIC driver to obtain touchscreen values continously. These values are then
* passed to the input susbsystem.
*
* @ingroup touchscreen
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/input.h>
#include <linux/init.h>
#include <linux/delay.h>
#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;
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;
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 */
if (0 != pmic_adc_get_touch_sample(&ts_sample, !(wait + wait2))) {
msleep(20);
continue;
}
if (!(ts_sample.contact_resistance || wait))
{
msleep(20);
continue;
}
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;
}
static int __init mxc_ts_init(void)
{
int retval;
if (!is_pmic_adc_ready())
return -ENODEV;
mxc_inputdev = input_allocate_device();
if (!mxc_inputdev) {
printk(KERN_ERR
"mxc_ts_init: not enough memory\n");
return -ENOMEM;
}
mxc_inputdev->name = MXC_TS_NAME;
mxc_inputdev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
mxc_inputdev->keybit[BIT_WORD(BTN_TOUCH)] |= BIT_MASK(BTN_TOUCH);
mxc_inputdev->absbit[0] =
BIT_MASK(ABS_X) | BIT_MASK(ABS_Y) | BIT_MASK(ABS_PRESSURE);
retval = input_register_device(mxc_inputdev);
if (retval < 0) {
input_free_device(mxc_inputdev);
return retval;
}
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)
{
if (tstask)
kthread_stop(tstask);
input_unregister_device(mxc_inputdev);
if (mxc_inputdev) {
input_free_device(mxc_inputdev);
mxc_inputdev = NULL;
}
}
late_initcall(mxc_ts_init);
module_exit(mxc_ts_exit);
MODULE_DESCRIPTION("MXC touchscreen driver with calibration");
MODULE_AUTHOR("Freescale Semiconductor, Inc.");
MODULE_LICENSE("GPL");
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