257 lines
6.9 KiB
C
257 lines
6.9 KiB
C
/****************************************************************************
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* boards/arm/kl/freedom-kl26z/src/kl_tsi.c
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*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership. The
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* ASF licenses this file to you under the Apache License, Version 2.0 (the
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* "License"); you may not use this file except in compliance with the
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* License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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*
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****************************************************************************/
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/* Reference:
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* https://community.freescale.com/community/
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* the-embedded-beat/blog/2012/10/15/
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* using-the-touch-interface-on-the-freescale-freedom-development-platform
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*/
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <nuttx/config.h>
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#include <stdint.h>
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#include <errno.h>
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#include <debug.h>
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#include <nuttx/fs/fs.h>
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#include "arm_internal.h"
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#include "kl_gpio.h"
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#include "hardware/kl_tsi.h"
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#include "hardware/kl_pinmux.h"
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#include "hardware/kl_sim.h"
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#ifdef CONFIG_KL_TSI
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/****************************************************************************
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* Pre-processor Definitions
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****************************************************************************/
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/* The touchpad on the Freedom KL26Z board connects to the MCU via:
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*
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* PTB16 TWI0_CH9
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* PTB17 TSI0_CH10
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*/
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#define NSENSORS 2
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/****************************************************************************
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* Private Function Prototypes
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****************************************************************************/
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static void tsi_calibrate(void);
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static ssize_t tsi_read(struct file *filep,
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char *buffer, size_t buflen);
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/****************************************************************************
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* Private Data
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****************************************************************************/
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static uint16_t g_defcap[NSENSORS]; /* Default capacitance for each sensor */
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static uint16_t g_currdelta = 0; /* Current delta for the current button */
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static uint8_t g_channel = 0; /* Current g_channel */
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/* Channel assigned to each sensor */
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static uint8_t const g_chsensor[NSENSORS] =
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{
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9,
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10
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};
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/* Character driver operations */
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static const struct file_operations tsi_ops =
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{
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NULL, /* open */
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NULL, /* close */
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tsi_read, /* read */
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NULL, /* write */
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NULL, /* seek */
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NULL, /* ioctl */
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NULL /* poll */
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#ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS
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, NULL /* unlink */
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#endif
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};
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/****************************************************************************
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* Private Functions
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****************************************************************************/
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/****************************************************************************
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* Name: tsi_calibrate
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****************************************************************************/
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static void tsi_calibrate(void)
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{
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uint32_t regval;
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int i;
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for (i = 0; i < NSENSORS; i++)
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{
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/* Clear end of scan flag */
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regval = getreg32(KL_TSI_GENCS);
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regval |= TSI_GENCS_EOSF;
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putreg32(regval, KL_TSI_GENCS);
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/* Scan the next electrode */
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regval = TSI_DATA_TSICH(g_chsensor[i]);
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putreg32(regval, KL_TSI_DATA);
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regval |= TSI_DATA_SWTS;
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putreg32(regval, KL_TSI_DATA);
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/* Wait until the conversion is done */
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while (!(getreg32(KL_TSI_GENCS) & TSI_GENCS_EOSF));
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g_defcap[i] = getreg32(KL_TSI_DATA) & TSI_DATA_TSICNT_MASK;
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iinfo("Sensor %d = %d\n", i + 1, g_defcap[i]);
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}
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}
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/****************************************************************************
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* Name: tsi_read
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****************************************************************************/
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static ssize_t tsi_read(struct file *filep, char *buf, size_t buflen)
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{
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static int deltacap = 0;
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uint32_t regval;
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if (buf == NULL || buflen < 1)
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{
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/* Well... nothing to do */
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return -EINVAL;
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}
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deltacap = 0;
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/* Clear end of scan flag */
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regval = getreg32(KL_TSI_GENCS);
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regval |= TSI_GENCS_EOSF;
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putreg32(regval, KL_TSI_GENCS);
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/* Scan the next electrode */
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regval = TSI_DATA_TSICH(g_chsensor[g_channel]);
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putreg32(regval, KL_TSI_DATA);
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regval |= TSI_DATA_SWTS;
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putreg32(regval, KL_TSI_DATA);
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/* Wait until the conversion is done */
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while (!(getreg32(KL_TSI_GENCS) & TSI_GENCS_EOSF));
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/* Compute delta using calibration reference counts */
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deltacap = getreg32(KL_TSI_DATA) & TSI_DATA_TSICNT_MASK;
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deltacap -= g_defcap[g_channel];
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if (deltacap < 0)
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{
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deltacap = 0;
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}
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g_currdelta = (uint16_t)deltacap;
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iinfo("Delta for g_channel %d = %d\n", g_channel, g_currdelta);
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buf[0] = g_currdelta & 0xff;
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buf[1] = (g_currdelta & 0xff00) >> 8;
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buf[2] = g_channel;
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/* Increment the channel index to sample the next sensor on the next timer
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* that read() is called.
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*/
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g_channel++;
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if (g_channel >= NSENSORS)
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{
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g_channel = 0;
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}
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return 3;
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}
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: kl_tsi_initialize
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*
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* Description:
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* Initialize the TSI hardware and interface for the sliders on board the
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* Freedom KL26Z board. Register a character driver at /dev/tsi that may
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* be used to read from each sensor.
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*
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****************************************************************************/
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void kl_tsi_initialize(void)
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{
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uint32_t regval;
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/* Enable access to the TSI module */
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regval = getreg32(KL_SIM_SCGC5);
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regval |= SIM_SCGC5_TSI;
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putreg32(regval, KL_SIM_SCGC5);
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/* Configure PINs used on TSI */
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kl_configgpio(PIN_TSI0_CH9);
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kl_configgpio(PIN_TSI0_CH10);
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/* Configure TSI parameter */
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regval = getreg32(KL_TSI_GENCS);
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regval |= TSI_GENCS_MODE_CAPSENSING | TSI_GENCS_REFCHRG_8UA |
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TSI_GENCS_DVOLT_1p03V | TSI_GENCS_EXTCHRG_64A |
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TSI_GENCS_PS_DIV16 | TSI_GENCS_NSCN_TIMES(12) | TSI_GENCS_STPE;
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putreg32(regval, KL_TSI_GENCS);
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/* Only after setting TSI we should enable it */
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regval = getreg32(KL_TSI_GENCS);
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regval |= TSI_GENCS_TSIEN;
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putreg32(regval, KL_TSI_GENCS);
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/* Calibrate it before to use */
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tsi_calibrate();
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/* And finally register the TSI character driver */
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register_driver("/dev/tsi", &tsi_ops, 0444, NULL);
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}
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#endif /* CONFIG_KL_TSI */
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