RK3588 spi 读写测试程序

根据提供的引用内容，以下是RK3568 SPI读写测试程序的步骤：

1. 首先，需要在设备树中配置SPI控制器。可以在设备树中添加类似以下的节点：

spi@ff1d0000 {
    compatible = "rockchip,rk3568-spi";
    reg = <0x0 0xff1d0000 0x0 0x10000>;
    interrupts = <GIC_SPI 123 IRQ_TYPE_LEVEL_HIGH>;
    dmas = <&pdma0 0 2 0>, <&pdma0 1 2 0>;
    dma-names = "rx", "tx";
    #address-cells = <1>;
    #size-cells = <0>;
    status = "okay";
};

2. 然后，需要在内核中注册SPI设备。可以使用以下代码：

#include <linux/spi/spi.h>

static struct spi_board_info spi_board_info = {
    .modalias = "spidev",
    .max_speed_hz = 5000000,
    .bus_num = 0,
    .chip_select = 0,
};

static struct spi_device *spi_dev;

int spi_init(void)
{
    struct spi_master *master;
    int ret;

    master = spi_busnum_to_master(spi_board_info.bus_num);
    if (!master) {
        printk(KERN_ERR "Failed to get SPI master\n");
        return -ENODEV;
    }

    spi_dev = spi_new_device(master, &spi_board_info);
    if (!spi_dev) {
        printk(KERN_ERR "Failed to create SPI device\n");
        return -ENODEV;
    }

    spi_dev->bits_per_word = 8;
    spi_dev->mode = SPI_MODE_0;
    spi_dev->max_speed_hz = spi_board_info.max_speed_hz;

    ret = spi_setup(spi_dev);
    if (ret) {
        printk(KERN_ERR "Failed to setup SPI device\n");
        spi_unregister_device(spi_dev);
        return ret;
    }

    return 0;
}

void spi_exit(void)
{
    spi_unregister_device(spi_dev);}

3. 接下来，可以使用SPI设备进行读写操作。可以使用以下代码：

#include <linux/spi/spi.h>

int spi_read_write(unsigned char *tx_buf, unsigned char *rx_buf, unsigned int len)
{
    struct spi_transfer transfer = {
        .tx_buf = tx_buf,
        .rx_buf = rx_buf,
        .len = len,
    };
    struct spi_message message;
    int ret;

    spi_message_init(&message);
    spi_message_add_tail(&transfer, &message);

    ret = spi_sync(spi_dev, &message);
    if (ret) {
        printk(KERN_ERR "SPI transfer failed\n");
        return ret;
    }

    return 0;
}

4. 最后，可以编写一个测试程序来测试SPI设备的读写功能。可以使用以下代码：

#include <linux/module.h>
#include <linux/kernel.h>

static unsigned char tx_buf[] = {0x01, 0x02, 0x03, 0x04};
static unsigned char rx_buf[4];

static int __init spi_test_init(void)
{
    int ret;

    ret = spi_init();
    if (ret) {
        return ret;
    }

    ret = spi_read_write(tx_buf, rx_buf, sizeof(tx_buf));
    if (ret) {
        spi_exit();
        return ret;
    }

    printk(KERN_INFO "SPI read/write test passed\n");

    spi_exit();

    return 0;
}

static void __exit spi_test_exit(void)
{
}

module_init(spi_test_init);
module_exit(spi_test_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Your Name");
MODULE_DESCRIPTION("SPI read/write test");