spicmds.c

// Commands for sending messages on an SPI bus
//
// Copyright (C) 2016  Kevin O'Connor <[email protected]>
//
// This file may be distributed under the terms of the GNU GPLv3 license.

#include <string.h> // memcpy
#include "board/gpio.h" // gpio_out_write
#include "basecmd.h" // oid_alloc
#include "command.h" // DECL_COMMAND
#include "sched.h" // sched_add_timer

#define SPI_BUFFER_SIZE 32

static struct task_wake spi_wake;

struct spi_dev_s {
    struct spi_config spi_config;
    struct gpio_out pin;
    char msg[SPI_BUFFER_SIZE];
    uint8_t len;
};

void
command_config_spi(uint32_t *args) {
    struct spi_dev_s *spi =
        oid_alloc(args[0], command_config_spi, sizeof(*spi));
    spi->pin = gpio_out_setup(args[1], 1);
    spi_config_init(&spi->spi_config, args[2], args[3], args[4]);
}
DECL_COMMAND(command_config_spi,
             "config_spi oid=%c bus=%u pin=%u mode=%u clock=%u");

void
command_spi_transfer(uint32_t *args)
{
    struct spi_dev_s *spi = oid_lookup(args[0], command_config_spi);

    if (args[1] > SPI_BUFFER_SIZE) {
        shutdown("SPI message larger then max size");
    }

    spi->len = args[1];
    memcpy(spi->msg, (void*)(size_t)args[2], spi->len);

    sched_wake_task(&spi_wake);
}
DECL_COMMAND(command_spi_transfer, "spi_transfer oid=%c data=%*s");

void
spi_task(void)
{
    if (!sched_check_wake(&spi_wake))
        return;

    uint8_t oid;
    struct spi_dev_s *spi;
    foreach_oid(oid, spi, command_config_spi) {
        spi_start(&spi->spi_config);
        gpio_out_write(spi->pin, 0);
        spi_exchange(&spi->spi_config, spi->len, spi->msg, spi->msg);
        gpio_out_write(spi->pin, 1);
        spi_stop(&spi->spi_config);
        sendf("spi_transfer_response oid=%c data=%*s", oid, spi->len, spi->msg);
    }
}
DECL_TASK(spi_task);

void
spi_shutdown(void) {
    uint8_t oid;
    struct spi_dev_s *spi;
    foreach_oid(oid, spi, command_config_spi) {
        gpio_out_write(spi->pin, 1);
    }
}
DECL_SHUTDOWN(spi_shutdown);