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/*
* Copyright (c) 2016 Adam Barth
*
* 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 <dev/gpio.h>
#include <errno.h>
#include <platform/bcm28xx.h>
#include <reg.h>
#define NUM_PINS 54
#define BITS_PER_REG 32
#define BITS_PER_PIN 3
#define PINS_PER_REG (BITS_PER_REG / BITS_PER_PIN)
#define GPIOREG(base, nr) (REG32(base) + (nr / BITS_PER_REG))
int gpio_config(unsigned nr, unsigned flags)
{
unsigned mask = 0x7;
if (nr >= NUM_PINS || flags & ~mask)
return -EINVAL;
unsigned register_number = nr / PINS_PER_REG;
unsigned offset = (nr % PINS_PER_REG) * BITS_PER_PIN;
unsigned shifted_mask = mask << offset;
volatile uint32_t *reg = REG32(GPIO_GPFSEL0) + register_number;
*reg = (*reg & ~shifted_mask) | (flags << offset);
return 0;
}
void gpio_set(unsigned nr, unsigned on)
{
unsigned offset = nr % BITS_PER_REG;
*GPIOREG(on ? GPIO_GPSET0 : GPIO_GPCLR0, nr) = 1 << offset;
}
int gpio_get(unsigned nr)
{
unsigned offset = nr % BITS_PER_REG;
return (*GPIOREG(GPIO_GPLEV0, nr) & (1 << offset)) >> offset;
}
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