383 lines
11 KiB
C
383 lines
11 KiB
C
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/*
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ChibiOS/HAL - Copyright (C) 2006-2014 Giovanni Di Sirio
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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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,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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/**
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* @file KINETIS/spi_lld.c
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* @brief KINETIS SPI subsystem low level driver source.
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*
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* @addtogroup SPI
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* @{
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*/
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#include "hal.h"
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#if HAL_USE_SPI || defined(__DOXYGEN__)
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/*===========================================================================*/
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/* Driver local definitions. */
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/*===========================================================================*/
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/*===========================================================================*/
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/* Driver exported variables. */
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/*===========================================================================*/
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/** @brief SPI0 driver identifier.*/
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#if KINETIS_SPI_USE_SPI0 || defined(__DOXYGEN__)
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SPIDriver SPID1;
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#endif
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/*===========================================================================*/
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/* Driver local variables and types. */
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/*===========================================================================*/
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/*===========================================================================*/
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/* Driver local functions. */
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/*===========================================================================*/
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static void spi_start_xfer(SPIDriver *spip, bool polling)
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{
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/*
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* Enable the DSPI peripheral in master mode.
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* On receive overflow, new data will overwrite old data.
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* Set slave selects to be active low.
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* Clear the TX and RX FIFOs.
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* */
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spip->spi->MCR = SPIx_MCR_MSTR |
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SPIx_MCR_ROOE |
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SPIx_MCR_PCSIS(KINETIS_SPI_PCS_ALL) |
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SPIx_MCR_CLR_TXF | SPIx_MCR_CLR_RXF;
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/* If we are not polling then enable interrupts */
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if (!polling) {
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/* Enable transmit fill, receive and end of queue interrupts */
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spip->spi->RSER = SPIx_RSER_TFFF_RE | SPIx_RSER_RFDF_RE |
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SPIx_RSER_EOQF_RE;
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}
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}
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static void spi_stop_xfer(SPIDriver *spip)
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{
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/* Halt the DSPI peripheral */
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spip->spi->MCR = SPIx_MCR_MSTR |
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SPIx_MCR_ROOE |
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SPIx_MCR_PCSIS(KINETIS_SPI_PCS_ALL) |
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SPIx_MCR_CLR_TXF | SPIx_MCR_CLR_RXF |
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SPIx_MCR_HALT;
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/* Clear all interrupt enables */
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spip->spi->RSER = 0;
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/* Clear all the flags which are currently set. */
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spip->spi->SR |= spip->spi->SR;
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}
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/*===========================================================================*/
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/* Driver interrupt handlers. */
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/*===========================================================================*/
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OSAL_IRQ_HANDLER(Vector70) {
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OSAL_IRQ_PROLOGUE();
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SPIDriver *spip = &SPID1;
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uint32_t sr = spip->spi->SR;
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/* Handle Receive FIFO Drain interrupt */
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if (sr & SPIx_SR_RFDF) {
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/* Pop the data out of the fifo */
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uint8_t data = spip->spi->POPR;
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/* If we have an rxbuf and it has space then store the data */
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if (spip->rxbuf && spip->rxidx < spip->nbytes) {
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spip->rxbuf[spip->rxidx++] = data;
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}
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/* Clear the Receive FIFO Drain Flag */
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spip->spi->SR = SPIx_SR_RFDF;
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}
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/* Handle End of Queue interrupt */
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if (sr & SPIx_SR_EOQF) {
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spip->spi->SR = SPIx_SR_EOQF;
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spi_stop_xfer(spip);
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_spi_isr_code(spip);
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}
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/* Handle Transmit FIFO Fill interrupt */
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if (sr & SPIx_SR_TFFF) {
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/* The data to send is either the next tx byte or a filler byte */
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uint8_t data = spip->txbuf ? spip->txbuf[spip->txidx] : 0x00;
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/* Calculate the number of bytes remaining and increment the index */
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size_t n = spip->nbytes - spip->txidx++;
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/* Push the data into the FIFO, CONT if more bytes, EOQ if last byte */
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spip->spi->PUSHR = (n > 1 ? SPIx_PUSHR_CONT : SPIx_PUSHR_EOQ) |
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SPIx_PUSHR_PCS(spip->config->pcs) |
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SPIx_PUSHR_TXDATA(data);
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/* Clear the Transmit FIFO Fill Flag */
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spip->spi->SR = SPIx_SR_TFFF;
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}
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OSAL_IRQ_EPILOGUE();
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}
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/*===========================================================================*/
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/* Driver exported functions. */
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/*===========================================================================*/
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/**
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* @brief Low level SPI driver initialization.
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*
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* @notapi
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*/
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void spi_lld_init(void) {
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nvicEnableVector(SPI0_IRQn, KINETIS_SPI_SPI0_IRQ_PRIORITY);
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#if KINETIS_SPI_USE_SPI0
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spiObjectInit(&SPID1);
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#endif
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}
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/**
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* @brief Configures and activates the SPI peripheral.
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*
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* @param[in] spip pointer to the @p SPIDriver object
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*
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* @notapi
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*/
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void spi_lld_start(SPIDriver *spip) {
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/* If in stopped state then enables the SPI and DMA clocks.*/
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if (spip->state == SPI_STOP) {
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#if KINETIS_SPI_USE_SPI0
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if (&SPID1 == spip) {
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/* Enable the clock for SPI0 */
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SIM->SCGC6 |= SIM_SCGC6_SPI0;
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SPID1.spi = SPI0;
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if (spip->config->tar0) {
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spip->spi->CTAR[0] = spip->config->tar0;
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} else {
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spip->spi->CTAR[0] = KINETIS_SPI_TAR0_DEFAULT;
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}
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spip->spi->CTAR[1] = KINETIS_SPI_TAR1_DEFAULT;
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}
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#endif
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}
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/* SPI setup and enable.*/
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}
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/**
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* @brief Deactivates the SPI peripheral.
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*
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* @param[in] spip pointer to the @p SPIDriver object
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*
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* @notapi
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*/
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void spi_lld_stop(SPIDriver *spip) {
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/* If in ready state then disables the SPI clock.*/
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if (spip->state == SPI_READY) {
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/* Disable the clock for SPI0 */
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SIM->SCGC6 &= ~SIM_SCGC6_SPI0;
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#if KINETIS_SPI_USE_SPI0
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if (&SPID1 == spip) {
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/* SPI halt.*/
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spip->spi->MCR |= SPIx_MCR_HALT;
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}
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#endif
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}
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}
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/**
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* @brief Asserts the slave select signal and prepares for transfers.
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*
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* @param[in] spip pointer to the @p SPIDriver object
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*
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* @notapi
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*/
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void spi_lld_select(SPIDriver *spip) {
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/* If we are not using the DSPI managed chip select then assert the SS */
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if (!spip->config->pcs) {
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palClearPad(spip->config->ssport, spip->config->sspad);
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}
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}
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/**
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* @brief Deasserts the slave select signal.
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* @details The previously selected peripheral is unselected.
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* This has no effect if we are using the KINETIS PCS mode to
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* manage slave select.
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*
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* @param[in] spip pointer to the @p SPIDriver object
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*
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* @notapi
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*/
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void spi_lld_unselect(SPIDriver *spip) {
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/* If we are not using the DSPI managed chip select then deassert the SS */
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if (!spip->config->pcs) {
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palSetPad(spip->config->ssport, spip->config->sspad);
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}
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}
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/**
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* @brief Ignores data on the SPI bus.
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* @details This asynchronous function starts the transmission of a series of
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* idle words on the SPI bus and ignores the received data.
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* @post At the end of the operation the configured callback is invoked.
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*
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* @param[in] spip pointer to the @p SPIDriver object
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* @param[in] n number of words to be ignored
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*
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* @notapi
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*/
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void spi_lld_ignore(SPIDriver *spip, size_t n) {
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spip->nbytes = n;
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spip->rxbuf = NULL;
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spip->rxidx = 0;
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spip->txbuf = NULL;
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spip->txidx = 0;
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spi_start_xfer(spip, false);
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}
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/**
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* @brief Exchanges data on the SPI bus.
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* @details This asynchronous function starts a simultaneous transmit/receive
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* operation.
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* @post At the end of the operation the configured callback is invoked.
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* @note The buffers are organized as uint8_t arrays for data sizes below or
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* equal to 8 bits else it is organized as uint16_t arrays.
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*
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* @param[in] spip pointer to the @p SPIDriver object
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* @param[in] n number of words to be exchanged
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* @param[in] txbuf the pointer to the transmit buffer
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* @param[out] rxbuf the pointer to the receive buffer
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*
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* @notapi
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*/
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void spi_lld_exchange(SPIDriver *spip, size_t n,
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const void *txbuf, void *rxbuf) {
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spip->nbytes = n;
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spip->rxbuf = rxbuf;
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spip->rxidx = 0;
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spip->txbuf = txbuf;
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spip->txidx = 0;
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spi_start_xfer(spip, false);
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}
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/**
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* @brief Sends data over the SPI bus.
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* @details This asynchronous function starts a transmit operation.
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* @post At the end of the operation the configured callback is invoked.
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* @note The buffers are organized as uint8_t arrays for data sizes below or
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* equal to 8 bits else it is organized as uint16_t arrays.
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*
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* @param[in] spip pointer to the @p SPIDriver object
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* @param[in] n number of words to send
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* @param[in] txbuf the pointer to the transmit buffer
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*
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* @notapi
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*/
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void spi_lld_send(SPIDriver *spip, size_t n, const void *txbuf) {
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spip->nbytes = n;
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spip->rxbuf = NULL;
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spip->rxidx = 0;
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spip->txbuf = (void *)txbuf;
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spip->txidx = 0;
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spi_start_xfer(spip, false);
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}
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/**
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* @brief Receives data from the SPI bus.
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* @details This asynchronous function starts a receive operation.
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* @post At the end of the operation the configured callback is invoked.
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* @note The buffers are organized as uint8_t arrays for data sizes below or
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* equal to 8 bits else it is organized as uint16_t arrays.
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*
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* @param[in] spip pointer to the @p SPIDriver object
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* @param[in] n number of words to receive
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* @param[out] rxbuf the pointer to the receive buffer
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*
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* @notapi
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*/
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void spi_lld_receive(SPIDriver *spip, size_t n, void *rxbuf) {
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spip->nbytes = n;
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spip->rxbuf = rxbuf;
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spip->rxidx = 0;
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spip->txbuf = NULL;
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spip->txidx = 0;
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spi_start_xfer(spip, false);
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}
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/**
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* @brief Exchanges one frame using a polled wait.
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* @details This synchronous function exchanges one frame using a polled
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* synchronization method. This function is useful when exchanging
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* small amount of data on high speed channels, usually in this
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* situation is much more efficient just wait for completion using
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* polling than suspending the thread waiting for an interrupt.
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*
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* @param[in] spip pointer to the @p SPIDriver object
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* @param[in] frame the data frame to send over the SPI bus
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* @return The received data frame from the SPI bus.
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*/
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uint16_t spi_lld_polled_exchange(SPIDriver *spip, uint16_t frame) {
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spi_start_xfer(spip, true);
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spip->spi->PUSHR = SPIx_PUSHR_PCS(0x10) | SPIx_PUSHR_TXDATA(frame);
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while ((spip->spi->SR & SPIx_SR_RFDF) == 0)
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;
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frame = spip->spi->POPR;
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spi_stop_xfer(spip);
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return frame;
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}
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#endif /* HAL_USE_SPI */
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/** @} */
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