gpio.c
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/*
* Copyright (C) 2014-2015 Freie Universität Berlin
* 2015 Kaspar Schleiser <kaspar@schleiser.de>
* 2015 FreshTemp, LLC.
*
* 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 driver_periph
* @{
*
* @file gpio.c
* @brief Low-level GPIO driver implementation
*
* @author Troels Hoffmeyer <troels.d.hoffmeyer@gmail.com>
* @author Thomas Eichinger <thomas.eichinger@fu-berlin.de>
* @author Kaspar Schleiser <kaspar@schleiser.de>
* @author Hauke Petersen <hauke.petersen@fu-berlin.de>
*
* @}
*/
#include "cpu.h"
#include "periph/gpio.h"
#define ENABLE_DEBUG (0)
#include "debug.h"
/**
* @brief Number of external interrupt lines
*/
#define NUMOF_IRQS (16U)
/**
* @brief Mask to get PINCFG reg value from mode value
*/
#define MODE_PINCFG_MASK (0x06)
/**
* @brief Mapping of pins to EXTI lines, -1 means not EXTI possible
*/
static const int8_t exti_config[2][32] = {
{ 0, 1, 2, 3, 4, 5, 6, 7, -1, 9, 10, 11, 12, 13, 14, 15,
0, 1, 2, 3, 4, 5, 6, 7, 12, 13, -1, 15, -1, -1, 10, 11},
{-1, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15,
0, 1, -1, -1, -1, -1, 6, 7, -1, -1, -1, -1, -1, -1, 14, 15},
};
static gpio_isr_ctx_t gpio_config[NUMOF_IRQS];
static inline PortGroup *_port(gpio_t pin)
{
return (PortGroup *)(pin & ~(0x1f));
}
static inline int _pin_pos(gpio_t pin)
{
return (pin & 0x1f);
}
static inline int _pin_mask(gpio_t pin)
{
return (1 << _pin_pos(pin));
}
static int _exti(gpio_t pin)
{
int port_num = ((pin >> 7) & 0x03);
if (port_num > 1) {
return -1;
}
return exti_config[port_num][_pin_pos(pin)];
}
void gpio_init_mux(gpio_t pin, gpio_mux_t mux)
{
PortGroup* port = _port(pin);
int pin_pos = _pin_pos(pin);
port->PINCFG[pin_pos].reg |= PORT_PINCFG_PMUXEN;
port->PMUX[pin_pos >> 1].reg &= ~(0xf << (4 * (pin_pos & 0x1)));
port->PMUX[pin_pos >> 1].reg |= (mux << (4 * (pin_pos & 0x1)));
}
int gpio_init(gpio_t pin, gpio_mode_t mode)
{
PortGroup* port = _port(pin);
int pin_pos = _pin_pos(pin);
int pin_mask = _pin_mask(pin);
/* make sure pin mode is applicable */
if (mode > 0x7) {
return -1;
}
/* set pin direction */
if (mode & 0x2) {
port->DIRCLR.reg = pin_mask;
}
else {
port->DIRSET.reg = pin_mask;
}
/* configure the pin cfg and clear output register */
port->PINCFG[pin_pos].reg = (mode & MODE_PINCFG_MASK);
port->OUTCLR.reg = pin_mask;
/* and set pull-up/pull-down if applicable */
if (mode == 0x7) {
port->OUTSET.reg = pin_mask;
}
return 0;
}
int gpio_init_int(gpio_t pin, gpio_mode_t mode, gpio_flank_t flank,
gpio_cb_t cb, void *arg)
{
int exti = _exti(pin);
/* make sure EIC channel is valid */
if (exti == -1) {
return -1;
}
/* save callback */
gpio_config[exti].cb = cb;
gpio_config[exti].arg = arg;
/* configure pin as input and set MUX to peripheral function A */
gpio_init(pin, mode);
gpio_init_mux(pin, GPIO_MUX_A);
/* enable clocks for the EIC module */
MCLK->APBAMASK.reg |= MCLK_APBAMASK_EIC;
GCLK->PCHCTRL[EIC_GCLK_ID].reg = GCLK_PCHCTRL_CHEN | GCLK_PCHCTRL_GEN_GCLK0;
/* configure the active flank */
EIC->CONFIG[exti >> 3].reg &= ~(0xf << ((exti & 0x7) * 4));
EIC->CONFIG[exti >> 3].reg |= (flank << ((exti & 0x7) * 4));
/* enable the global EIC interrupt */
NVIC_EnableIRQ(EIC_IRQn);
/*Enable pin interrupt */
EIC->INTFLAG.reg = (1 << exti);
EIC->INTENSET.reg = (1 << exti);
/* enable the EIC module*/
EIC->CTRLA.reg = EIC_CTRLA_ENABLE;
while (EIC->SYNCBUSY.reg & EIC_SYNCBUSY_ENABLE) {}
return 0;
}
void gpio_irq_enable(gpio_t pin)
{
int exti = _exti(pin);
if (exti == -1) {
return;
}
EIC->INTENSET.reg = (1 << exti);
}
void gpio_irq_disable(gpio_t pin)
{
int exti = _exti(pin);
if (exti == -1) {
return;
}
EIC->INTENCLR.reg = (1 << exti);
}
int gpio_read(gpio_t pin)
{
PortGroup *port = _port(pin);
int mask = _pin_mask(pin);
if (port->DIR.reg & mask) {
return (port->OUT.reg & mask) ? 1 : 0;
}
else {
return (port->IN.reg & mask) ? 1 : 0;
}
}
void gpio_set(gpio_t pin)
{
_port(pin)->OUTSET.reg = _pin_mask(pin);
}
void gpio_clear(gpio_t pin)
{
_port(pin)->OUTCLR.reg = _pin_mask(pin);
}
void gpio_toggle(gpio_t pin)
{
_port(pin)->OUTTGL.reg = _pin_mask(pin);
}
void gpio_write(gpio_t pin, int value)
{
if (value) {
_port(pin)->OUTSET.reg = _pin_mask(pin);
} else {
_port(pin)->OUTCLR.reg = _pin_mask(pin);
}
}
void isr_eic(void)
{
for (int i = 0; i < NUMOF_IRQS; i++) {
if (EIC->INTFLAG.reg & (1 << i)) {
EIC->INTFLAG.reg = (1 << i);
gpio_config[i].cb(gpio_config[i].arg);
}
}
cortexm_isr_end();
}