contiki/cpu/cc2538/dev/spi.c
Benoît Thébaudeau e8a8870d1d cc2538: spi: Add enable and disable functions
This makes it possible to reduce the power consumption when the SPI is unused.

Signed-off-by: Benoît Thébaudeau <benoit.thebaudeau@advansee.com>
2013-11-20 14:20:50 +01:00

127 lines
4.9 KiB
C

/*
* Copyright (c) 2013, University of Michigan.
* All rights reserved.
*
* 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 of the University 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 INSTITUTE 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 INSTITUTE 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.
*/
/**
* \addtogroup cc2538-spi
* @{
*
* \file
* Implementation of the cc2538 SPI peripheral
*/
#include "contiki.h"
#include "reg.h"
#include "spi-arch.h"
#include "dev/ioc.h"
#include "dev/sys-ctrl.h"
#include "dev/spi.h"
#include "dev/ssi.h"
#include "dev/gpio.h"
/* Default: Motorola mode 3 with 8-bit data words */
#ifndef SPI_CONF_PHASE
#define SPI_CONF_PHASE SSI_CR0_SPH
#endif
#ifndef SPI_CONF_POLARITY
#define SPI_CONF_POLARITY SSI_CR0_SPO
#endif
#ifndef SPI_CONF_DATA_SIZE
#define SPI_CONF_DATA_SIZE 8
#endif
#if SPI_CONF_DATA_SIZE < 4 || SPI_CONF_DATA_SIZE > 16
#error SPI_CONF_DATA_SIZE must be set between 4 and 16 inclusive.
#endif
/**
* \brief Initialize the SPI bus.
*
* This SPI init() function uses the following #defines to set the pins:
* CC2538_SPI_CLK_PORT_NUM CC2538_SPI_CLK_PIN_NUM
* CC2538_SPI_MOSI_PORT_NUM CC2538_SPI_MOSI_PIN_NUM
* CC2538_SPI_MISO_PORT_NUM CC2538_SPI_MISO_PIN_NUM
* CC2538_SPI_SEL_PORT_NUM CC2538_SPI_SEL_PIN_NUM
*
* This sets the mode to Motorola SPI with the following format options:
* SPI_CONF_PHASE: 0 or SSI_CR0_SPH
* SPI_CONF_POLARITY: 0 or SSI_CR0_SPO
* SPI_CONF_DATA_SIZE: 4 to 16 bits
*/
void
spi_init(void)
{
spi_enable();
/* Start by disabling the peripheral before configuring it */
REG(SSI0_BASE + SSI_CR1) = 0;
/* Set the IO clock as the SSI clock */
REG(SSI0_BASE + SSI_CC) = 1;
/* Set the mux correctly to connect the SSI pins to the correct GPIO pins */
ioc_set_sel(CC2538_SPI_CLK_PORT_NUM, CC2538_SPI_CLK_PIN_NUM, IOC_PXX_SEL_SSI0_CLKOUT);
ioc_set_sel(CC2538_SPI_MOSI_PORT_NUM, CC2538_SPI_MOSI_PIN_NUM, IOC_PXX_SEL_SSI0_TXD);
REG(IOC_SSIRXD_SSI0) = (CC2538_SPI_MISO_PORT_NUM * 8) + CC2538_SPI_MISO_PIN_NUM;
ioc_set_sel(CC2538_SPI_SEL_PORT_NUM, CC2538_SPI_SEL_PIN_NUM, IOC_PXX_SEL_SSI0_FSSOUT);
/* Put all the SSI gpios into peripheral mode */
GPIO_PERIPHERAL_CONTROL(GPIO_PORT_TO_BASE(CC2538_SPI_CLK_PORT_NUM), GPIO_PIN_MASK(CC2538_SPI_CLK_PIN_NUM));
GPIO_PERIPHERAL_CONTROL(GPIO_PORT_TO_BASE(CC2538_SPI_MOSI_PORT_NUM), GPIO_PIN_MASK(CC2538_SPI_MOSI_PIN_NUM));
GPIO_PERIPHERAL_CONTROL(GPIO_PORT_TO_BASE(CC2538_SPI_MISO_PORT_NUM), GPIO_PIN_MASK(CC2538_SPI_MISO_PIN_NUM));
GPIO_PERIPHERAL_CONTROL(GPIO_PORT_TO_BASE(CC2538_SPI_SEL_PORT_NUM), GPIO_PIN_MASK(CC2538_SPI_SEL_PIN_NUM));
/* Disable any pull ups or the like */
ioc_set_over(CC2538_SPI_CLK_PORT_NUM, CC2538_SPI_CLK_PIN_NUM, IOC_OVERRIDE_DIS);
ioc_set_over(CC2538_SPI_MOSI_PORT_NUM, CC2538_SPI_MOSI_PIN_NUM, IOC_OVERRIDE_DIS);
ioc_set_over(CC2538_SPI_MISO_PORT_NUM, CC2538_SPI_MISO_PIN_NUM, IOC_OVERRIDE_DIS);
ioc_set_over(CC2538_SPI_SEL_PORT_NUM, CC2538_SPI_SEL_PIN_NUM, IOC_OVERRIDE_DIS);
/* Configure the clock */
REG(SSI0_BASE + SSI_CPSR) = 2;
/* Put the ssi in Motorola SPI mode using the provided format options */
REG(SSI0_BASE + SSI_CR0) = SPI_CONF_PHASE | SPI_CONF_POLARITY | (SPI_CONF_DATA_SIZE - 1);
/* Enable the SSI */
REG(SSI0_BASE + SSI_CR1) |= SSI_CR1_SSE;
}
/*---------------------------------------------------------------------------*/
void
spi_enable(void)
{
/* Enable the clock for the SSI peripheral */
REG(SYS_CTRL_RCGCSSI) |= 1;
}
/*---------------------------------------------------------------------------*/
void
spi_disable(void)
{
/* Gate the clock for the SSI peripheral */
REG(SYS_CTRL_RCGCSSI) &= ~1;
}
/** @} */