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// samd21 gpio functions
//
// Copyright (C) 2018 Kevin O'Connor <kevin@koconnor.net>
//
// This file may be distributed under the terms of the GNU GPLv3 license.
#include <string.h> // ffs
#include "board/irq.h" // irq_save
#include "command.h" // shutdown
#include "gpio.h" // gpio_out_setup
#include "internal.h" // gpio_peripheral
#include "samd21.h" // PORT
#include "sched.h" // sched_shutdown
/****************************************************************
* Pin multiplexing
****************************************************************/
void
gpio_peripheral(char bank, uint32_t bit, char ptype, uint32_t pull_up)
{
int group = bank == 'A' ? 0 : 1;
PortGroup *pg = &PORT->Group[group];
if (ptype) {
volatile uint8_t *pmux = &pg->PMUX[bit/2].reg;
uint8_t shift = (bit & 1) ? 4 : 0, mask = ~(0xf << shift);
*pmux = (*pmux & mask) | ((ptype - 'A') << shift);
}
pg->PINCFG[bit].reg = ((ptype ? PORT_PINCFG_PMUXEN : 0)
| (pull_up ? PORT_PINCFG_PULLEN : 0));
}
/****************************************************************
* General Purpose Input Output (GPIO) pins
****************************************************************/
#define GPIO(PORT, NUM) (((PORT)-'A') * 32 + (NUM))
#define GPIO2PORT(PIN) ((PIN) / 32)
#define GPIO2BIT(PIN) (1<<((PIN) % 32))
#define NUM_PORT 2
struct gpio_out
gpio_out_setup(uint8_t pin, uint8_t val)
{
if (GPIO2PORT(pin) >= NUM_PORT)
goto fail;
PortGroup *pg = &PORT->Group[GPIO2PORT(pin)];
struct gpio_out g = { .regs=pg, .bit=GPIO2BIT(pin) };
gpio_out_reset(g, val);
return g;
fail:
shutdown("Not an output pin");
}
static void
set_pincfg(PortGroup *pg, uint32_t bit, uint8_t cfg)
{
pg->PINCFG[ffs(bit)-1].reg = cfg;
}
void
gpio_out_reset(struct gpio_out g, uint8_t val)
{
PortGroup *pg = g.regs;
irqstatus_t flag = irq_save();
if (val)
pg->OUTSET.reg = g.bit;
else
pg->OUTCLR.reg = g.bit;
pg->DIRSET.reg = g.bit;
set_pincfg(pg, g.bit, 0);
irq_restore(flag);
}
void
gpio_out_toggle_noirq(struct gpio_out g)
{
PortGroup *pg = g.regs;
pg->OUTTGL.reg = g.bit;
}
void
gpio_out_toggle(struct gpio_out g)
{
gpio_out_toggle_noirq(g);
}
void
gpio_out_write(struct gpio_out g, uint8_t val)
{
PortGroup *pg = g.regs;
if (val)
pg->OUTSET.reg = g.bit;
else
pg->OUTCLR.reg = g.bit;
}
struct gpio_in
gpio_in_setup(uint8_t pin, int8_t pull_up)
{
if (GPIO2PORT(pin) >= NUM_PORT)
goto fail;
PortGroup *pg = &PORT->Group[GPIO2PORT(pin)];
struct gpio_in g = { .regs=pg, .bit=GPIO2BIT(pin) };
gpio_in_reset(g, pull_up);
return g;
fail:
shutdown("Not an input pin");
}
void
gpio_in_reset(struct gpio_in g, int8_t pull_up)
{
PortGroup *pg = g.regs;
irqstatus_t flag = irq_save();
set_pincfg(pg, g.bit, pull_up > 0 ? PORT_PINCFG_PULLEN : 0);
pg->DIRCLR.reg = g.bit;
irq_restore(flag);
}
uint8_t
gpio_in_read(struct gpio_in g)
{
PortGroup *pg = g.regs;
return !!(pg->IN.reg & g.bit);
}
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