w25q32的spi驱动

下面是一个简单的w25q32的SPI驱动示例，可以用来读取芯片中的数据：

#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#include <linux/types.h>
#include <linux/spi/spidev.h>

#define SPI_MODE SPI_MODE_0
#define SPI_BITS_PER_WORD 8
#define SPI_SPEED 1000000 // 1MHz

int main(int argc, char *argv[]) {
    int fd;
    uint8_t tx[4], rx[4];
    struct spi_ioc_transfer spi;

    // Open the SPI device
    fd = open("/dev/spidev0.0", O_RDWR);
    if (fd < 0) {
        perror("Error opening SPI device");
        exit(EXIT_FAILURE);
    }

    // Configure the SPI mode, bits per word, and speed
    uint8_t mode = SPI_MODE;
    if (ioctl(fd, SPI_IOC_WR_MODE, &mode) < 0) {
        perror("Error setting SPI mode");
        exit(EXIT_FAILURE);
    }
    uint8_t bits_per_word = SPI_BITS_PER_WORD;
    if (ioctl(fd, SPI_IOC_WR_BITS_PER_WORD, &bits_per_word) < 0) {
        perror("Error setting SPI bits per word");
        exit(EXIT_FAILURE);
    }
    uint32_t speed = SPI_SPEED;
    if (ioctl(fd, SPI_IOC_WR_MAX_SPEED_HZ, &speed) < 0) {
        perror("Error setting SPI speed");
        exit(EXIT_FAILURE);
    }

    // Read data from the W25Q32 SPI flash chip
    tx[0] = 0x03; // Read command
    tx[1] = 0x00; // Address byte 1
    tx[2] = 0x00; // Address byte 2
    tx[3] = 0x00; // Address byte 3
    memset(rx, 0, sizeof(rx));
    spi.tx_buf = (unsigned long) tx;
    spi.rx_buf = (unsigned long) rx;
    spi.len = 4;
    spi.delay_usecs = 0;
    spi.speed_hz = speed;
    spi.bits_per_word = bits_per_word;
    if (ioctl(fd, SPI_IOC_MESSAGE(1), &spi) < 0) {
        perror("Error reading from SPI flash chip");
        exit(EXIT_FAILURE);
    }

    // Print the read data
    printf("Read data: %02X %02X %02X %02X\n", rx[0], rx[1], rx[2], rx[3]);

    // Close the SPI device
    close(fd);

    return 0;
}

在该示例中，我们使用Linux的SPI设备驱动程序来与W25Q32 SPI闪存芯片通信。我们打开SPI设备文件`/dev/spidev0.0`，然后使用`ioctl()`函数来设置SPI模式、字长和速度。然后，我们将读取命令和地址发送到芯片，并使用`ioctl()`函数读取数据。最后，我们打印读取的数据并关闭SPI设备。