rt-thread/bsp/at91sam9g45/drivers/at91_i2c_gpio.c

/*
 * Copyright (c) 2006-2021, RT-Thread Development Team
 *
 * SPDX-License-Identifier: Apache-2.0
 *
 * Change Logs:
 * Date           Author        Notes
 * 2012-04-25     weety     first version
 */

#include <rtdevice.h>
#include <rthw.h>
#include <at91sam9g45.h>


static void at91_i2c_gpio_init()
{
    AT91C_BASE_PMC->PMC_PCER  = 1 << AT91C_ID_PIOA; //enable PIOA clock
    AT91C_BASE_PIOA->PIO_PUER = (1 << 23);
    AT91C_BASE_PIOA->PIO_PER  = (1 << 23);
    AT91C_BASE_PIOA->PIO_MDER = (1 << 23);
    AT91C_BASE_PIOA->PIO_PUER = (1 << 24);
    AT91C_BASE_PIOA->PIO_PER  = (1 << 24);
    AT91C_BASE_PIOA->PIO_MDER = (1 << 24);

    AT91C_BASE_PIOA->PIO_OER  = (1 << 23);
    AT91C_BASE_PIOA->PIO_OER  = (1 << 24);

    AT91C_BASE_PIOA->PIO_SODR = (1 << 23);
    AT91C_BASE_PIOA->PIO_SODR = (1 << 24);
}

static void at91_set_sda(void *data, rt_int32_t state)
{
    if (state)
    {
        AT91C_BASE_PIOA->PIO_SODR = (1 << 23);
    }
    else
    {
        AT91C_BASE_PIOA->PIO_CODR = (1 << 23);
    }
}

static void at91_set_scl(void *data, rt_int32_t state)
{
    if (state)
    {
        AT91C_BASE_PIOA->PIO_SODR = (1 << 24);
    }
    else
    {
        AT91C_BASE_PIOA->PIO_CODR = (1 << 24);
    }
}

static rt_int32_t  at91_get_sda(void *data)
{
    return AT91C_BASE_PIOA->PIO_PDSR & (1 << 23);
}

static rt_int32_t  at91_get_scl(void *data)
{
    return AT91C_BASE_PIOA->PIO_PDSR & (1 << 24);
}

static void at91_udelay (rt_uint32_t us)
{
    rt_int32_t i;
    for (; us > 0; us--)
    {
        i = 50000;
        while(i > 0)
        {
            i--;
        }
    }
}

static const struct rt_i2c_bit_ops bit_ops = {
    RT_NULL,
    at91_set_sda,
    at91_set_scl,
    at91_get_sda,
    at91_get_scl,

    at91_udelay,

    5,
    100
};

int at91_i2c_init(void)
{
    struct rt_i2c_bus_device *bus;

    bus = rt_malloc(sizeof(struct rt_i2c_bus_device));
    if (bus == RT_NULL)
    {
        rt_kprintf("rt_malloc failed\n");
        return -RT_ENOMEM;
    }

    rt_memset((void *)bus, 0, sizeof(struct rt_i2c_bus_device));

    bus->priv = (void *)&bit_ops;

    at91_i2c_gpio_init();

    rt_i2c_bit_add_bus(bus, "i2c0");

    return 0;
}

INIT_DEVICE_EXPORT(at91_i2c_init);