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RIOT/cpu/samd21/periph/spi.c
Hauke Petersen ac6b73a35c cpu/samd21(common): cleaned up pad selection macros
- renamed uart and spi pad selection macros to consistent style
- adapted uart and spi implementation to use new names
2016-10-07 11:02:14 +02:00

321 lines
7.5 KiB
C

/*
* Copyright (C) 2014 Freie Universität Berlin
*
* This file is subject to the terms and conditions of the GNU Lesser General
* Public License v2.1. See the file LICENSE in the top level directory for more
* details.
*/
/**
* @ingroup cpu_samd21
* @{
*
* @file
* @brief Low-level SPI driver implementation
*
* @author Thomas Eichinger <thomas.eichinger@fu-berlin.de>
* @author Troels Hoffmeyer <troels.d.hoffmeyer@gmail.com>
* @author Hauke Petersen <hauke.petersen@fu-berlin.de>
* @author Joakim Nohlgård <joakim.nohlgard@eistec.se>
*
* @}
*/
#include "cpu.h"
#include "mutex.h"
#include "periph/gpio.h"
#include "periph/spi.h"
#include "periph_conf.h"
#include "board.h"
#define ENABLE_DEBUG (0)
#include "debug.h"
#if SPI_0_EN || SPI_1_EN
/**
* @brief Internal helper function to do the actual work for spi_poweroff
*/
static void _spi_poweroff(SercomSpi* spi_dev);
/**
* @brief Internal helper function to do the actual work for spi_poweron
*/
static void _spi_poweron(SercomSpi* spi_dev);
/**
* @brief Array holding one pre-initialized mutex for each SPI device
*/
static mutex_t locks[] = {
#if SPI_0_EN
[SPI_0] = MUTEX_INIT,
#endif
#if SPI_1_EN
[SPI_1] = MUTEX_INIT,
#endif
#if SPI_2_EN
[SPI_2] = MUTEX_INIT
#endif
};
int spi_init_master(spi_t dev, spi_conf_t conf, spi_speed_t speed)
{
SercomSpi* spi_dev = 0;
uint8_t sercom_gclk_id = 0;
gpio_t pin_sclk = 0;
gpio_t pin_miso = 0;
gpio_t pin_mosi = 0;
gpio_mux_t mux_sclk = 0;
gpio_mux_t mux_miso = 0;
gpio_mux_t mux_mosi = 0;
spi_mosipad_t mosi_pad = 0;
spi_misopad_t miso_pad = 0;
uint32_t cpha = 0;
uint32_t cpol = 0;
uint32_t f_baud = 0;
switch (speed)
{
case SPI_SPEED_100KHZ:
f_baud = 100000;
break;
case SPI_SPEED_400KHZ:
f_baud = 400000;
break;
case SPI_SPEED_1MHZ:
f_baud = 1000000;
break;
case SPI_SPEED_5MHZ:
#if CLOCK_CORECLOCK >= 5000000
f_baud = 5000000;
break;
#else
return -1;
#endif
case SPI_SPEED_10MHZ:
#if CLOCK_CORECLOCK >= 10000000
f_baud = 10000000;
break;
#else
return -1;
#endif
}
switch (conf)
{
case SPI_CONF_FIRST_RISING: /**< first data bit is transacted on the first rising SCK edge */
cpha = 0;
cpol = 0;
break;
case SPI_CONF_SECOND_RISING: /**< first data bit is transacted on the second rising SCK edge */
cpha = SERCOM_SPI_CTRLA_CPHA;
cpol = 0;
break;
case SPI_CONF_FIRST_FALLING: /**< first data bit is transacted on the first falling SCK edge */
cpha = 0;
cpol = SERCOM_SPI_CTRLA_CPOL;
break;
case SPI_CONF_SECOND_FALLING: /**< first data bit is transacted on the second falling SCK edge */
cpha = SERCOM_SPI_CTRLA_CPHA;
cpol = SERCOM_SPI_CTRLA_CPOL;
break;
}
switch (dev)
{
#if SPI_0_EN
case SPI_0:
spi_dev = &SPI_0_DEV;
sercom_gclk_id = SPI_0_GCLK_ID;
pin_sclk = SPI_0_SCLK;
mux_sclk = SPI_0_SCLK_MUX;
pin_miso = SPI_0_MISO;
mux_miso = SPI_0_MISO_MUX;
pin_mosi = SPI_0_MOSI;
mux_mosi = SPI_0_MOSI_MUX;
mosi_pad = SPI_0_MOSI_PAD;
miso_pad = SPI_0_MISO_PAD;
break;
#endif
#if SPI_1_EN
case SPI_1:
spi_dev = &SPI_1_DEV;
sercom_gclk_id = SPI_1_GCLK_ID;
pin_sclk = SPI_1_SCLK;
mux_sclk = SPI_1_SCLK_MUX;
pin_miso = SPI_1_MISO;
mux_miso = SPI_1_MISO_MUX;
pin_mosi = SPI_1_MOSI;
mux_mosi = SPI_1_MOSI_MUX;
mosi_pad = SPI_1_MOSI_PAD;
miso_pad = SPI_1_MISO_PAD;
break;
#endif
default:
return -1;
}
/* Use the same sequence as ArduinoCore
* - setup pins
* - disable SPI
* - init SPI (reset, init clock NVIC, CTRLA, CTRLB)
* - init cpha/cpol, BAUD.reg
* - enable SPI
*/
gpio_init(pin_miso, GPIO_IN_PD);
gpio_init_mux(pin_sclk, mux_sclk);
gpio_init_mux(pin_miso, mux_miso);
gpio_init_mux(pin_mosi, mux_mosi);
/* Disable spi to write confs */
_spi_poweroff(spi_dev);
/* reset */
// Setting the Software Reset bit to 1
spi_dev->CTRLA.bit.SWRST = 1;
// Wait both bits Software Reset from CTRLA and SYNCBUSY are equal to 0
while (spi_dev->CTRLA.bit.SWRST || spi_dev->SYNCBUSY.bit.SWRST) {}
/* Turn on power manager for sercom */
PM->APBCMASK.reg |= (PM_APBCMASK_SERCOM0 << (sercom_gclk_id - GCLK_CLKCTRL_ID_SERCOM0_CORE_Val));
/* Setup clock */
/* SPI using CLK GEN 0 */
GCLK->CLKCTRL.reg = (GCLK_CLKCTRL_CLKEN |
GCLK_CLKCTRL_GEN_GCLK0 |
GCLK_CLKCTRL_ID(sercom_gclk_id));
while (GCLK->STATUS.bit.SYNCBUSY) {}
/* ???? init NVIC. Maybe not needed in master mode. */
/* Master mode */
spi_dev->CTRLA.reg |= SERCOM_SPI_CTRLA_MODE_SPI_MASTER;
while (spi_dev->SYNCBUSY.reg) {}// ???? not needed
spi_dev->BAUD.bit.BAUD = (uint8_t) (((uint32_t)CLOCK_CORECLOCK) / (2 * f_baud) - 1); /* Synchronous mode*/
spi_dev->CTRLA.reg |= SERCOM_SPI_CTRLA_DOPO(mosi_pad)
| SERCOM_SPI_CTRLA_DIPO(miso_pad)
| cpha
| cpol;
while (spi_dev->SYNCBUSY.reg) {} // ???? not needed
/* datasize 0 => 8 bits */
spi_dev->CTRLB.reg = (SERCOM_SPI_CTRLB_CHSIZE(0) | SERCOM_SPI_CTRLB_RXEN);
while (spi_dev->SYNCBUSY.reg) {} // ???? Only wait for clear of spi_dev->SYNCBUSY.bit.CTRLB
/* enable */
_spi_poweron(spi_dev);
return 0;
}
int spi_init_slave(spi_t dev, spi_conf_t conf, char (*cb)(char))
{
/* TODO */
return -1;
}
void spi_transmission_begin(spi_t dev, char reset_val)
{
/* TODO*/
}
int spi_acquire(spi_t dev)
{
if ((unsigned int)dev >= SPI_NUMOF) {
return -1;
}
mutex_lock(&locks[dev]);
return 0;
}
int spi_release(spi_t dev)
{
if ((unsigned int)dev >= SPI_NUMOF) {
return -1;
}
mutex_unlock(&locks[dev]);
return 0;
}
int spi_transfer_byte(spi_t dev, char out, char *in)
{
SercomSpi* spi_dev = 0;
char tmp;
switch(dev)
{
#if SPI_0_EN
case SPI_0:
spi_dev = &(SPI_0_DEV);
break;
#endif
#if SPI_1_EN
case SPI_1:
spi_dev = &(SPI_1_DEV);
break;
#endif
}
while (!spi_dev->INTFLAG.bit.DRE) {} /* while data register is not empty*/
spi_dev->DATA.bit.DATA = out;
while (!spi_dev->INTFLAG.bit.DRE || !spi_dev->INTFLAG.bit.RXC) {} /* while receive is not complete*/
tmp = (char)spi_dev->DATA.bit.DATA;
if (in != NULL)
{
in[0] = tmp;
}
return 1;
}
static void _spi_poweron(SercomSpi* spi_dev)
{
if (spi_dev == NULL) {
return;
}
spi_dev->CTRLA.reg |= SERCOM_SPI_CTRLA_ENABLE;
while (spi_dev->SYNCBUSY.bit.ENABLE) {}
}
void spi_poweron(spi_t dev)
{
switch(dev) {
#if SPI_0_EN
case SPI_0:
_spi_poweron(&SPI_0_DEV);
break;
#endif
#if SPI_1_EN
case SPI_1:
_spi_poweron(&SPI_1_DEV);
break;
#endif
}
}
static void _spi_poweroff(SercomSpi* spi_dev)
{
if (spi_dev == NULL) {
return;
}
spi_dev->CTRLA.bit.ENABLE = 0; /* Disable spi */
while (spi_dev->SYNCBUSY.bit.ENABLE) {}
}
void spi_poweroff(spi_t dev)
{
switch(dev) {
#if SPI_0_EN
case SPI_0:
_spi_poweroff(&SPI_0_DEV);
break;
#endif
#if SPI_1_EN
case SPI_1:
_spi_poweroff(&SPI_1_DEV);
break;
#endif
}
}
#endif /* SPI_0_EN || SPI_1_EN */