206 lines
8.8 KiB
C
206 lines
8.8 KiB
C
/*
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* Copyright (c) 2015, Freescale Semiconductor, Inc.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without modification,
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* are permitted provided that the following conditions are met:
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*
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* o Redistributions of source code must retain the above copyright notice, this list
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* of conditions and the following disclaimer.
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*
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* o Redistributions in binary form must reproduce the above copyright notice, this
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* list of conditions and the following disclaimer in the documentation and/or
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* other materials provided with the distribution.
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*
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* o Neither the name of Freescale Semiconductor, Inc. nor the names of its
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* contributors may be used to endorse or promote products derived from this
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* software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR
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* ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
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* ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include "ecspi.h"
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/*******************************************************************************
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* Code
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******************************************************************************/
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/*******************************************************************************
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* eCSPI Initialization and Configuration functions
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******************************************************************************/
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/*FUNCTION**********************************************************************
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*
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* Function Name : ECSPI_Init
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* Description : Initializes the eCSPI module according to the specified
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* parameters in the initConfig.
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*
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*END**************************************************************************/
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void ECSPI_Init(ECSPI_Type* base, const ecspi_init_config_t* initConfig)
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{
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/* Disable eCSPI module */
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ECSPI_CONREG_REG(base) = 0;
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/* Enable the eCSPI module before write to other registers */
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ECSPI_Enable(base);
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/* eCSPI CONREG Configuration */
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ECSPI_CONREG_REG(base) |= ECSPI_CONREG_BURST_LENGTH(initConfig->burstLength) |
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ECSPI_CONREG_CHANNEL_SELECT(initConfig->channelSelect);
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ECSPI_CONREG_REG(base) |= initConfig->ecspiAutoStart ? ECSPI_CONREG_SMC_MASK : 0;
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/* eCSPI CONFIGREG Configuration */
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ECSPI_CONFIGREG_REG(base) = ECSPI_CONFIGREG_SCLK_PHA(((initConfig->clockPhase) & 1) << (initConfig->channelSelect)) |
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ECSPI_CONFIGREG_SCLK_POL(((initConfig->clockPolarity) & 1) << (initConfig->channelSelect));
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/* Master or Slave mode Configuration */
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if(initConfig->mode == ecspiMasterMode)
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{
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/* Set baud rate in bits per second */
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ECSPI_CONREG_REG(base) |= ECSPI_CONREG_CHANNEL_MODE(1 << (initConfig->channelSelect));
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ECSPI_SetBaudRate(base, initConfig->clockRate, initConfig->baudRate);
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}
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else
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ECSPI_CONREG_REG(base) &= ~ECSPI_CONREG_CHANNEL_MODE(1 << (initConfig->channelSelect));
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}
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/*FUNCTION**********************************************************************
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*
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* Function Name : ECSPI_SetSampClockSource
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* Description : Configure the clock source for the sample period counter.
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*
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*END**************************************************************************/
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void ECSPI_SetSampClockSource(ECSPI_Type* base, uint32_t source)
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{
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/* Select the clock source */
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if(source == ecspiSclk)
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ECSPI_PERIODREG_REG(base) &= ~ECSPI_PERIODREG_CSRC_MASK;
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else
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ECSPI_PERIODREG_REG(base) |= ECSPI_PERIODREG_CSRC_MASK;
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}
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/*FUNCTION**********************************************************************
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*
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* Function Name : ECSPI_SetBaudRate
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* Description : Calculated the eCSPI baud rate in bits per second.
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*
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*END**************************************************************************/
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uint32_t ECSPI_SetBaudRate(ECSPI_Type* base, uint32_t sourceClockInHz, uint32_t bitsPerSec)
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{
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uint32_t div, pre_div;
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uint32_t post_baud; /* baud rate after post divider */
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uint32_t pre_baud; /* baud rate before pre divider */
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if(sourceClockInHz <= bitsPerSec)
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{
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ECSPI_CONREG_REG(base) &= ~ECSPI_CONREG_PRE_DIVIDER_MASK;
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ECSPI_CONREG_REG(base) &= ~ECSPI_CONREG_POST_DIVIDER_MASK;
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return sourceClockInHz;
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}
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div = sourceClockInHz / bitsPerSec;
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if(div < 16) /* pre_divider is enough */
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{
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if((sourceClockInHz - bitsPerSec * div) < ((bitsPerSec * (div + 1)) - sourceClockInHz))
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pre_div = div - 1; /* pre_divider value is one less than the real divider */
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else
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pre_div = div;
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ECSPI_CONREG_REG(base) = (ECSPI_CONREG_REG(base) & (~ECSPI_CONREG_PRE_DIVIDER_MASK)) |
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ECSPI_CONREG_PRE_DIVIDER(pre_div);
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ECSPI_CONREG_REG(base) = (ECSPI_CONREG_REG(base) & (~ECSPI_CONREG_POST_DIVIDER_MASK)) |
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ECSPI_CONREG_POST_DIVIDER(0);
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return sourceClockInHz / (pre_div + 1);
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}
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pre_baud = bitsPerSec * 16;
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for(div = 1; div < 16; div++)
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{
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post_baud = sourceClockInHz >> div;
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if(post_baud < pre_baud)
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break;
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}
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if(div == 16) /* divider is not enough, set the biggest ones */
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{
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ECSPI_CONREG_REG(base) |= ECSPI_CONREG_PRE_DIVIDER(15);
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ECSPI_CONREG_REG(base) |= ECSPI_CONREG_POST_DIVIDER(15);
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return post_baud / 16;
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}
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/* find the closed one */
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if((post_baud - bitsPerSec * (post_baud / bitsPerSec)) < ((bitsPerSec * ((post_baud / bitsPerSec) + 1)) - post_baud))
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pre_div = post_baud / bitsPerSec - 1;
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else
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pre_div = post_baud / bitsPerSec;
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ECSPI_CONREG_REG(base) = (ECSPI_CONREG_REG(base) & (~ECSPI_CONREG_PRE_DIVIDER_MASK)) |
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ECSPI_CONREG_PRE_DIVIDER(pre_div);
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ECSPI_CONREG_REG(base) = (ECSPI_CONREG_REG(base) & (~ECSPI_CONREG_POST_DIVIDER_MASK)) |
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ECSPI_CONREG_POST_DIVIDER(div);
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return post_baud / (pre_div + 1);
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}
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/*******************************************************************************
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* DMA management functions
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******************************************************************************/
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/*FUNCTION**********************************************************************
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*
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* Function Name : ECSPI_SetDMACmd
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* Description : Enable or disable the specified DMA Source.
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*
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*END**************************************************************************/
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void ECSPI_SetDMACmd(ECSPI_Type* base, uint32_t source, bool enable)
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{
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/* Configure the DAM source */
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if(enable)
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ECSPI_DMAREG_REG(base) |= ((uint32_t)(1 << source));
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else
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ECSPI_DMAREG_REG(base) &= ~((uint32_t)(1 << source));
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}
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/*FUNCTION**********************************************************************
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*
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* Function Name : ECSPI_SetFIFOThreshold
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* Description : Set the RXFIFO or TXFIFO threshold.
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*
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*END**************************************************************************/
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void ECSPI_SetFIFOThreshold(ECSPI_Type* base, uint32_t fifo, uint32_t threshold)
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{
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/* configure the RXFIFO and TXFIFO threshold that can triggers a DMA/INT request */
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if(fifo == ecspiTxfifoThreshold)
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ECSPI_DMAREG_REG(base) = (ECSPI_DMAREG_REG(base) & (~ECSPI_DMAREG_TX_THRESHOLD_MASK)) |
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ECSPI_DMAREG_TX_THRESHOLD(threshold);
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else
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ECSPI_DMAREG_REG(base) = (ECSPI_DMAREG_REG(base) & (~ECSPI_DMAREG_RX_THRESHOLD_MASK)) |
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ECSPI_DMAREG_RX_THRESHOLD(threshold);
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}
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/*******************************************************************************
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* Interrupts and flags management functions
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******************************************************************************/
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/*FUNCTION**********************************************************************
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*
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* Function Name : ECSPI_SetIntCmd
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* Description : Enable or disable eCSPI interrupts.
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*
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*END**************************************************************************/
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void ECSPI_SetIntCmd(ECSPI_Type* base, uint32_t flags, bool enable)
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{
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/* Configure the Interrupt source */
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if(enable)
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ECSPI_INTREG_REG(base) |= flags;
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else
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ECSPI_INTREG_REG(base) &= ~flags;
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}
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/*******************************************************************************
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* EOF
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******************************************************************************/
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