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/*
* Copyright (c) 2018 Richard Braun.
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
* DEALINGS IN THE SOFTWARE.
*/
#include <stdbool.h>
#include <stdint.h>
#include "gpio.h"
#define GPIO_C_BASE_ADDR 0x40020800
struct gpio_regs {
uint32_t moder;
uint32_t otyper;
uint32_t ospeedr;
uint32_t pupdr;
uint32_t idr;
uint32_t odr;
uint32_t bsrr;
uint32_t lckr;
uint32_t afrl;
uint32_t afrh;
};
static volatile struct gpio_regs *gpio_c_regs = (void *)GPIO_C_BASE_ADDR;
static void
gpio_compute_location(unsigned int io, unsigned int nr_bits,
uint32_t *shift, uint32_t *mask)
{
*shift = (io * nr_bits);
*mask = ((1 << nr_bits) - 1) << *shift;
}
static void
gpio_set_af(volatile struct gpio_regs *regs, unsigned int io,
uint32_t af, uint32_t speed, uint32_t pupd)
{
uint32_t shift, mask, value;
volatile uint32_t *reg;
gpio_compute_location(io, 2, &shift, &mask);
value = (af == 15) ? 1 : 2;
regs->moder &= ~mask;
regs->moder |= value << shift;
gpio_compute_location(io, 2, &shift, &mask);
regs->ospeedr &= ~mask;
regs->ospeedr |= speed << shift;
gpio_compute_location(io, 2, &shift, &mask);
regs->pupdr &= ~mask;
regs->pupdr |= pupd << shift;
if (io < 8) {
reg = ®s->afrl;
} else {
reg = ®s->afrh;
io -= 8;
}
gpio_compute_location(io, 4, &shift, &mask);
*reg &= ~mask;
*reg |= af << shift;
}
static void
gpio_set_output(volatile struct gpio_regs *regs, unsigned int io, bool high)
{
uint32_t shift, mask;
gpio_compute_location(io, 1, &shift, &mask);
if (high) {
regs->odr |= high << shift;
} else {
regs->odr &= ~mask;
}
}
void
gpio_setup(void)
{
gpio_set_af(gpio_c_regs, 6, 8, 1, 1); /* UART6 TX */
gpio_set_af(gpio_c_regs, 7, 8, 1, 1); /* UART6 RX */
gpio_set_af(gpio_c_regs, 13, 15, 0, 0); /* LED */
}
void
gpio_led_on(void)
{
gpio_set_output(gpio_c_regs, 13, false);
}
void
gpio_led_off(void)
{
gpio_set_output(gpio_c_regs, 13, true);
}
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