drv_spi.c

/*
 * Copyright (c) 2006-2021, RT-Thread Development Team
 *
 * SPDX-License-Identifier: Apache-2.0
 *
 * Change Logs:
 * Date           Author                   Notes
 * 2020-10-28     0xcccccccccccc           Initial Version
 * 2021-01-17     0xcccccccccccc           Bug Fixed : clock division cannot been adjusted as expected due to wrong register configuration.
 */

/**
 * @addtogroup ls2k
 */
/*@{*/

#include <stdlib.h>
#include <ctype.h>
#include <stdint.h>
#include <rtthread.h>
#include <drivers/spi.h>
#include "drv_spi.h"

#ifdef RT_USING_SPI
#ifdef RT_USING_SPI_GPIOCS
#include <drivers/pin.h>
#endif

static void spi_init(uint8_t spre_spr, uint8_t copl, uint8_t cpha)
{
    SET_SPI(SPSR, 0xc0);
    SET_SPI(PARAM, 0x40);
    SET_SPI(PARAM2, 0x01);
    SET_SPI(SPER, (spre_spr & 0b00001100) >> 2);
    SET_SPI(SPCR, 0x50 | copl << 3 | cpha << 2 | (spre_spr & 0b00000011));
    SET_SPI(SOFTCS, 0xff);
}

rt_inline void spi_set_csn(uint8_t val)
{
    SET_SPI(SOFTCS, val);
}

static void spi_set_cs(unsigned char cs, int new_status)
{
    if (cs < 4)
    {
        unsigned char val = 0;
        val = GET_SPI(SOFTCS);
        val |= 0x01 << cs ;     // csen=1
        if (new_status)         // cs = 1
        {
            val |= (0x10 << cs);            // csn=1
        }
        else                    // cs = 0
        {
            val &= ~(0x10 << cs);           // csn=0
        }
        SET_SPI(SOFTCS, val);
        return ;
    }
#ifdef RT_USING_SPI_GPIOCS
    else
    {
        rt_pin_mode(cs, PIN_MODE_OUTPUT); // with RT_USING_SPI_GPIOCS feature enabled, gpio will be used as csn pin.
        rt_pin_write(cs, new_status);
    }
#endif
}

static uint8_t spi_write_for_response(uint8_t data)
{
    uint8_t val;
    SET_SPI(TXFIFO, data);
    while ((GET_SPI(SPSR))&RFEMPTY); //wait for echo
    val = GET_SPI(RXFIFO);
    return val;
}

static int cmd_spi_init(int argc, char *argv[])
{
    uint8_t spre_spr, cpol, cpha;
    switch (argc)
    {
    case 2:
        spre_spr = strtoul(argv[1], NULL, 0);
        spi_init(spre_spr, 0, 0);
        break;
    case 4:
        spre_spr = strtoul(argv[1], NULL, 0);
        cpol = strtoul(argv[2], NULL, 0);
        cpha = strtoul(argv[3], NULL, 0);
        spi_init(spre_spr, 0, 0);
        break;
    default:
        printf("\nusage : cmd_spi_init spre_spr <cpol> <cpha>\n(cmd_spi_init 0x4 0x0 0x0)\n0x4:div8 0xb:div4096\n");
        break;
    }
}
MSH_CMD_EXPORT(cmd_spi_init, cmd_spi_init);

static int cmd_spi_set_csn(int argc, char *argv[])
{
    uint8_t val, csn;
    switch (argc)
    {
    case 3:
        csn = strtoul(argv[1], NULL, 0);
        val = strtoul(argv[2], NULL, 0);
        spi_set_cs(csn, val);
        break;
    default:
        printf("usage:cmd_spi_set_csn csn val\n(0xbf for csn1 enable,0xff for csn1 disable)\n");
        break;
    }
}
MSH_CMD_EXPORT(cmd_spi_set_csn, cmd_spi_set_csn);

static int cmd_spi_write(int argc, char *argv[])
{
    uint8_t data, resp;
    switch (argc)
    {
    case 2:
        data = strtoul(argv[1], NULL, 0);
        resp = spi_write_for_response(data);
        printf("resp:%2X\n", resp);
        break;
    default:
        printf("usage:cmd_spi_write data\n");
        break;
    }
}
MSH_CMD_EXPORT(cmd_spi_write, cmd_spi_write);

static rt_err_t configure(struct rt_spi_device *device, struct rt_spi_configuration *configuration);
static rt_uint32_t xfer(struct rt_spi_device *device, struct rt_spi_message *message);

const static unsigned char SPI_DIV_TABLE[] = {0b0000, 0b0001, 0b0100, 0b0010, 0b0011, 0b0101, 0b0110, 0b0111, 0b1000, 0b1001, 0b1010, 0b1011};
// 2      4      8      16     32     64      128   256    512    1024   2048   4096
static rt_err_t configure(struct rt_spi_device *device,
                          struct rt_spi_configuration *configuration)
{

    unsigned char cpol = 0;
    unsigned char cpha = 0;

    RT_ASSERT(NULL != device);
    RT_ASSERT(NULL != configuration);

    // baudrate
    if (configuration->mode & RT_SPI_CPOL)      // cpol
    {
        cpol = 1;
    }
    else
    {
        cpol = 0;
    }
    if (configuration->mode & RT_SPI_CPHA)      // cpha
    {
        cpha = 1;
    }
    else
    {
        cpha = 0;
    }

    float spi_max_speed = ((float)APB_MAX_SPEED) / (8.0 / (float)APB_FREQSCALE);
    uint64_t div = (uint64_t)(spi_max_speed / (float)configuration->max_hz);
    int ctr = 0;
    while (div != 1 && ctr < 12)
    {
        ctr++;
        div = div >> 1;
    }
    spi_init(SPI_DIV_TABLE[ctr], cpol, cpha);

    return RT_EOK;
}

static rt_uint32_t xfer(struct rt_spi_device *device, struct rt_spi_message *message)
{

    unsigned char cs = 0;
    rt_uint32_t size = 0;
    const rt_uint8_t *send_ptr = NULL;
    rt_uint8_t *recv_ptr = NULL;
    rt_uint8_t data = 0;
    RT_ASSERT(NULL != device);
    RT_ASSERT(NULL != message);
    cs = (unsigned char)(device->parent.user_data);
    size = message->length;
    if (message->cs_take)
    {
        spi_set_cs(cs, 0);
    }
    // send data
    send_ptr = message->send_buf;
    recv_ptr = message->recv_buf;
    while (size--)
    {
        data = 0xFF;
        if (NULL != send_ptr)
        {
            data = *send_ptr++;
        }
        if (NULL != recv_ptr)
        {
            *recv_ptr++ = spi_write_for_response(data);
        }
        else
        {
            spi_write_for_response(data);
        }
    }
    // release cs
    if (message->cs_release)
    {
        spi_set_cs(cs, 1);
    }
    return message->length;
}

static struct rt_spi_ops loongson_spi_ops =
{
    .configure  = configure,
    .xfer       = xfer
};
static struct rt_spi_bus loongson_spi;

static int loongson_spi_init()
{
    //rt_kprintf("spi_init\n");
    return rt_spi_bus_register(&loongson_spi, "spi", &loongson_spi_ops);
}
INIT_BOARD_EXPORT(loongson_spi_init);
#endif
/*@}*/