/****************************************************************************
* configs/freedom-kl25z/src/kl_tsi.c
*
* Copyright (C) 2013 Alan Carvalho de Assis
* Author: Alan Carvalho de Assis <acassis@gmail.com>
* with adaptions from Gregory Nutt <gnutt@nuttx.org>
*
* Reference: https://community.freescale.com/community/
* the-embedded-beat/blog/2012/10/15/
* using-the-touch-interface-on-the-freescale-freedom-development-platform
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* 3. Neither the name NuttX nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <stdint.h>
#include <errno.h>
#include <debug.h>
#include <nuttx/fs/fs.h>
#include "up_arch.h"
#include "kl_gpio.h"
#include "chip/kl_tsi.h"
#include "chip/kl_pinmux.h"
#include "chip/kl_sim.h"
#ifdef CONFIG_KL_TSI
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/* The touchpad on the Freedom KL25Z board connects to the MCU via:
*
* PTB16 TWI0_CH9
* PTB17 TSI0_CH10
*/
#define NSENSORS 2
/****************************************************************************
* Private Function Prototypes
****************************************************************************/
static void tsi_calibrate(void);
static ssize_t tsi_read(FAR struct file *filep, FAR char *buffer, size_t buflen);
/****************************************************************************
* Private Data
****************************************************************************/
static uint16_t g_defcap[NSENSORS]; /* Default capacitance for each sensor */
static uint16_t g_currdelta = 0; /* Current delta for the current button */
static uint8_t g_channel = 0; /* Current g_channel */
/* Channel assigned to each sensor */
static uint8_t const g_chsensor[NSENSORS] = { 9, 10 };
/* Character driver operations */
static const struct file_operations tsi_ops =
{
0, /* open */
0, /* close */
tsi_read, /* read */
0, /* write */
0, /* seek */
0, /* ioctl */
};
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: tsi_calibrate
****************************************************************************/
static void tsi_calibrate(void)
{
uint32_t regval;
int i;
for (i = 0; i < NSENSORS; i++)
{
/* Clear end of scan flag */
regval = getreg32(KL_TSI_GENCS);
regval |= TSI_GENCS_EOSF;
putreg32(regval, KL_TSI_GENCS);
/* Scan the next electrode */
regval = TSI_DATA_TSICH(g_chsensor[i]);
putreg32(regval, KL_TSI_DATA);
regval |= TSI_DATA_SWTS;
putreg32(regval, KL_TSI_DATA);
/* Wait until the conversion is done */
while (!(getreg32(KL_TSI_GENCS) & TSI_GENCS_EOSF));
g_defcap[i] = getreg32(KL_TSI_DATA) & TSI_DATA_TSICNT_MASK;
ivdbg("Sensor %d = %d\n", i+1, g_defcap[i]);
}
}
/****************************************************************************
* Name: tsi_read
****************************************************************************/
static ssize_t tsi_read(FAR struct file *filep, FAR char *buf, size_t buflen)
{
static int deltacap = 0;
uint32_t regval;
if (buf == NULL || buflen < 1)
{
/* Well... nothing to do */
return -EINVAL;
}
deltacap = 0;
/* Clear end of scan flag */
regval = getreg32(KL_TSI_GENCS);
regval |= TSI_GENCS_EOSF;
putreg32(regval, KL_TSI_GENCS);
/* Scan the next electrode */
regval = TSI_DATA_TSICH(g_chsensor[g_channel]);
putreg32(regval, KL_TSI_DATA);
regval |= TSI_DATA_SWTS;
putreg32(regval, KL_TSI_DATA);
/* Wait until the conversion is done*/
while (!(getreg32(KL_TSI_GENCS) & TSI_GENCS_EOSF));
/* Compute delta using calibration reference counts */
deltacap = getreg32(KL_TSI_DATA) & TSI_DATA_TSICNT_MASK;
deltacap -= g_defcap[g_channel];
if (deltacap < 0)
{
deltacap = 0;
}
g_currdelta = (uint16_t)deltacap;
ivdbg("Delta for g_channel %d = %d\n", g_channel, g_currdelta);
buf[0] = g_currdelta & 0xff;
buf[1] = (g_currdelta & 0xff00) >> 8;
buf[2] = g_channel;
/* Increment the channel index to sample the next sensor on the next timer
* that read() is called.
*/
g_channel++;
if (g_channel >= NSENSORS)
{
g_channel = 0;
}
return 3;
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: kl_tsi_initialize
*
* Description:
* Initialize the TSI hardware and interface for the sliders on board the
* Freedom KL25Z board. Register a character driver at /dev/tsi that may
* be used to read from each sensor.
*
****************************************************************************/
void kl_tsi_initialize(void)
{
uint32_t regval;
/* Enable access to the TSI module */
regval = getreg32(KL_SIM_SCGC5);
regval |= SIM_SCGC5_TSI;
putreg32(regval, KL_SIM_SCGC5);
/* Configure PINs used on TSI */
kl_configgpio(PIN_TSI0_CH9);
kl_configgpio(PIN_TSI0_CH10);
/* Configure TSI parameter */
regval = getreg32(KL_TSI_GENCS);
regval |= TSI_GENCS_MODE_CAPSENSING | TSI_GENCS_REFCHRG_8UA |
TSI_GENCS_DVOLT_1p03V | TSI_GENCS_EXTCHRG_64A |
TSI_GENCS_PS_DIV16 | TSI_GENCS_NSCN_TIMES(12) | TSI_GENCS_STPE;
putreg32(regval, KL_TSI_GENCS);
/* Only after setting TSI we should enable it */
regval = getreg32(KL_TSI_GENCS);
regval |= TSI_GENCS_TSIEN;
putreg32(regval, KL_TSI_GENCS);
/* Calibrate it before to use */
tsi_calibrate();
/* And finally register the TSI character driver */
(void)register_driver("/dev/tsi", &tsi_ops, 0444, NULL);
}
#endif /* CONFIG_KL_TSI */
