238 lines
6.2 KiB
C
238 lines
6.2 KiB
C
/*
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ChibiOS-LCD-Driver - Copyright (C) 2012
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Joel Bodenmann aka Tectu <joel@unormal.org>
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This file is part of ChibiOS-LCD-Driver.
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ChibiOS-LCD-Driver is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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ChibiOS-LCD-Driver is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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/**
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* @file touchpadADS7843/touchpad_lld.c
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* @brief Touchpad Driver subsystem low level driver source.
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*
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* @addtogroup TOUCHPAD
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* @{
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*/
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#include "ch.h"
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#include "hal.h"
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#include "touchpad.h"
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#if HAL_USE_TOUCHPAD || defined(__DOXYGEN__)
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/*===========================================================================*/
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/* Driver local definitions. */
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/*===========================================================================*/
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#ifdef UNUSED
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#elif defined(__GNUC__)
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# define UNUSED(x) UNUSED_ ## x __attribute__((unused))
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#elif defined(__LCLINT__)
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# define UNUSED(x) /*@unused@*/ x
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#else
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# define UNUSED(x) x
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#endif
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/*===========================================================================*/
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/* Driver exported variables. */
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/*===========================================================================*/
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/*===========================================================================*/
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/* Driver local variables. */
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/*===========================================================================*/
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#if !defined(__DOXYGEN__)
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/* Local copy of the current touchpad driver */
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static const TOUCHPADDriver *tpDriver;
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static uint16_t sampleBuf[7];
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#endif
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/*===========================================================================*/
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/* Driver local functions. */
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/*===========================================================================*/
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/*===========================================================================*/
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/* Driver interrupt handlers. */
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/*===========================================================================*/
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/*===========================================================================*/
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/* Driver exported functions. */
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/*===========================================================================*/
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/* ---- Required Routines ---- */
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/**
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* @brief Low level Touchpad driver initialization.
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*
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* @notapi
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*/
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void tp_lld_init(const TOUCHPADDriver *tp) {
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tpDriver=tp;
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if (tpDriver->direct_init)
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spiStart(tpDriver->spip, tpDriver->spicfg);
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}
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/**
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* @brief Reads a conversion from the touchpad
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*
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* @param[in] cmd The command bits to send to the touchpad
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*
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* @return The read value 12-bit right-justified
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*
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* @note This function only reads data, it is assumed that the pins are
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* configured properly and the bus has been acquired beforehand
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*
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* @notapi
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*/
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uint16_t tp_lld_read_value(uint8_t cmd) {
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static uint8_t txbuf[3]={0};
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static uint8_t rxbuf[3]={0};
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uint16_t ret;
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txbuf[0]=cmd;
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spiExchange(tpDriver->spip, 3, txbuf, rxbuf);
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ret = (rxbuf[1] << 5) | (rxbuf[2] >> 3);
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return ret;
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}
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/**
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* @brief 7-point median filtering code for touchpad samples
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*
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* @note This is an internally used routine only.
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*
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* @notapi
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*/
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static void tp_lld_filter(void) {
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uint16_t temp;
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int i,j;
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for (i=0; i<4; i++) {
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for (j=i; j<7; j++) {
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if (sampleBuf[i] > sampleBuf[j]) {
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/* Swap the values */
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temp=sampleBuf[i];
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sampleBuf[i]=sampleBuf[j];
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sampleBuf[j]=temp;
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}
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}
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}
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}
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/**
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* @brief Reads out the X direction.
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*
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* @note The samples are median filtered for greater noise reduction
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*
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* @notapi
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*/
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uint16_t tp_lld_read_x(void) {
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int i;
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#if defined(SPI_USE_MUTUAL_EXCLUSION)
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spiAcquireBus(tpDriver->spip);
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#endif
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TOUCHPAD_SPI_PROLOGUE();
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palClearPad(tpDriver->spicfg->ssport, tpDriver->spicfg->sspad);
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/* Discard the first conversion - very noisy and keep the ADC on hereafter
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* till we are done with the sampling. Note that PENIRQ is disabled.
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*/
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tp_lld_read_value(0xD1);
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for (i=0;i<7;i++) {
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sampleBuf[i]=tp_lld_read_value(0xD1);
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}
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/* Switch on PENIRQ once again - perform a dummy read */
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tp_lld_read_value(0xD0);
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palSetPad(tpDriver->spicfg->ssport, tpDriver->spicfg->sspad);
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TOUCHPAD_SPI_EPILOGUE();
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#if defined(SPI_USE_MUTUAL_EXCLUSION)
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spiReleaseBus(tpDriver->spip);
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#endif
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/* Find the median - use selection sort */
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tp_lld_filter();
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return sampleBuf[3];
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}
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/*
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* @brief Reads out the Y direction.
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*
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* @notapi
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*/
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uint16_t tp_lld_read_y(void) {
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int i;
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#if defined(SPI_USE_MUTUAL_EXCLUSION)
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spiAcquireBus(tpDriver->spip);
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#endif
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TOUCHPAD_SPI_PROLOGUE();
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palClearPad(tpDriver->spicfg->ssport, tpDriver->spicfg->sspad);
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/* Discard the first conversion - very noisy and keep the ADC on hereafter
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* till we are done with the sampling. Note that PENIRQ is disabled.
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*/
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tp_lld_read_value(0x91);
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for (i=0;i<7;i++) {
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sampleBuf[i]=tp_lld_read_value(0x91);
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}
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/* Switch on PENIRQ once again - perform a dummy read */
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tp_lld_read_value(0x90);
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palSetPad(tpDriver->spicfg->ssport, tpDriver->spicfg->sspad);
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TOUCHPAD_SPI_EPILOGUE();
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#ifdef SPI_USE_MUTUAL_EXCLUSION
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spiReleaseBus(tpDriver->spip);
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#endif
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/* Find the median - use selection sort */
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tp_lld_filter();
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return sampleBuf[3];
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}
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/* ---- Optional Routines ---- */
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#if TOUCHPAD_HAS_IRQ || defined(__DOXYGEN__)
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/*
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* @brief for checking if touchpad is pressed or not.
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*
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* @return 1 if pressed / 0 if not pressed
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*
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* @notapi
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*/
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uint8_t tp_lld_irq(void) {
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return (!palReadPad(tpDriver->tpIRQPort, tpDriver->tpIRQPin));
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}
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#endif
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#endif /* HAL_USE_TOUCHPAD */
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/** @} */
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