Linux w5500驱动调用代码

以下是一个使用Linux SPI总线和W5500芯片的驱动程序示例，可供参考：

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/spi/spi.h>
#include <linux/of_gpio.h>
#include <linux/gpio.h>

#define W5500_SPI_MODE (SPI_MODE_0)
#define W5500_SPI_BITS_PER_WORD (8)
#define W5500_SPI_MAX_SPEED_HZ (10 * 1000 * 1000)

struct w5500_data {
    struct spi_device *spi;
    struct gpio_desc *reset_gpio;
};

static int w5500_reset(struct w5500_data *w5500)
{
    if (!w5500->reset_gpio)
        return -ENODEV;

    gpiod_set_value_cansleep(w5500->reset_gpio, 1);
    msleep(10);
    gpiod_set_value_cansleep(w5500->reset_gpio, 0);
    msleep(10);
    gpiod_set_value_cansleep(w5500->reset_gpio, 1);
    msleep(150);

    return 0;
}

static int w5500_probe(struct spi_device *spi)
{
    struct device *dev = &spi->dev;
    struct w5500_data *w5500;
    int ret;

    w5500 = devm_kzalloc(dev, sizeof(*w5500), GFP_KERNEL);
    if (!w5500)
        return -ENOMEM;

    spi->bits_per_word = W5500_SPI_BITS_PER_WORD;
    spi_setup(spi);

    w5500->spi = spi;

    w5500->reset_gpio = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH);
    if (IS_ERR(w5500->reset_gpio)) {
        ret = PTR_ERR(w5500->reset_gpio);
        dev_err(dev, "Failed to get reset GPIO: %d\n", ret);
        return ret;
    }

    ret = w5500_reset(w5500);
    if (ret) {
        dev_err(dev, "Failed to reset W5500: %d\n", ret);
        return ret;
    }

    return 0;
}

static int w5500_remove(struct spi_device *spi)
{
    struct w5500_data *w5500 = spi_get_drvdata(spi);

    if (w5500_reset(w5500)) {
        dev_warn(&spi->dev, "Failed to reset W5500 on removal\n");
    }

    return 0;
}

static const struct of_device_id w5500_of_match[] = {
    { .compatible = "wiznet,w5500", },
    { },
};
MODULE_DEVICE_TABLE(of, w5500_of_match);

static struct spi_driver w5500_driver = {
    .driver = {
        .name = "w5500",
        .of_match_table = w5500_of_match,
    },
    .probe = w5500_probe,
    .remove = w5500_remove,
};

module_spi_driver(w5500_driver);
MODULE_AUTHOR("Your Name");
MODULE_DESCRIPTION("W5500 SPI driver");
MODULE_LICENSE("GPL");

此驱动程序在设备树中使用以下属性：

spi {
    #address-cells = <1>;
    #size-cells = <0>;

    w5500@0 {
        compatible = "wiznet,w5500";
        reg = <0>;
        spi-max-frequency = <10000000>;
        reset-gpios = <&gpio1 2 GPIO_ACTIVE_HIGH>;
    };
};

该驱动程序使用 `devm_gpiod_get()` 函数获取重置 GPIO 引脚，以及 `gpiod_set_value_cansleep()` 函数将 GPIO 引脚设置为适当的值。它还使用 SPI API 函数来设置 SPI 总线并进行数据传输。